Space travel: the health effects of space radiation and building a lunar GPS

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Hello, and welcome to the Physics World Weekly

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podcast.

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I'm Hamish Johnston.

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We are entering a second golden age of

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space travel

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with human missions to the moon and Mars

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planned for the near future.

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In this podcast, we explore 2 very different

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challenges facing the next generation

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of cosmic explorers.

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Coming up, I'm in conversation with 2 physicists

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about how we could implement

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a universal

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time standard for the moon

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which would come in handy for navigating

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lunar environments.

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But first, Physics World's Tammy Freeman is in

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conversation

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with an expert on the biological

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effects of radiation

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on space travelers.

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Radiation from space is all around us,

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whether this is solar radiation from the sun

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or the constant bombardment by galactic cosmic rays.

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On Earth, we're protected from most of this

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radiation

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by our planet's geomagnetic field and thick atmosphere.

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But for those who venture beyond the protection

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of the Earth,

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exposure to space radiation can have a significant

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impact on the human body.

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And with future missions planned to return astronauts

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to the moon or beyond,

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the radiation associated risks of such space travel

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are a serious consideration.

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A newly published ebook

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entitled Space Radiation

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takes an in-depth look at the astrophysical

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origins of this radiation,

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its biological effects, and the implications for space

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travelers.

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I'm speaking today with the book's author,

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James Welsh,

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from Loyola Medical School in Illinois, USA

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to find out more. Welcome to the podcast,

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James.

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Thank you.

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So you've written an extremely comprehensive book looking

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at all aspects of space radiation.

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What motivated you to write this?

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Well, thank you very much, Tammy, for this

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opportunity to speak with you today.

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And that might be the toughest question

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of all

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because to this day, I still don't know

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what truly

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provided the motivation to embark on such a

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monumental task. But

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number of years back, I had the opportunity

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to teach an astrobiology

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honors course

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at Northern Illinois University.

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And astrobiology

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got me very interested in this topic of

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space radiation.

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I then had the chance to give a

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couple of lectures at Fermilab,

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Fermilab National Accelerator Laboratory in Illinois,

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on the Ask A Scientist program.

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One of the

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topics I chose to, talk about was called

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radiation from outer space, gamma rays of death,

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doom, and destruction.

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And then I did a follow-up one on

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the sky's the limit,

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radiation hazards of space travel.

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Preparing for and delivering those lectures really got

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me fascinated in the subject, and so I

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wanted to maybe tabulate all my ideas

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in the form of a book.

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But what started out as a a small

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project

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in which I was planning to collect and

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edit a series of chapters from,

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colleagues,

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the whole concept deteriorated

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during the COVID 19 pandemic,

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and I could no longer get my colleagues

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to contribute

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chapters.

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So I wound up writing the whole

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book myself.

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It developed into a very stressful

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several year project in which the 800 pages,

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were finally completed,

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earlier this year. And so this product of

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the pandemic is now completed and available.

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That's the best answer I have for

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got me going and this project.

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Oh, that's a great answer. So, and who

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are the targeted readers for the book?

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So

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perhaps

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based on the idea that, this really got

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started after teaching the honors undergraduate

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course at Northern Illinois University,

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I suppose that the book,

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could be

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geared for undergraduate level

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physics majors,

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biology majors,

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astronomy majors. It is largely written at the

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introductory level, so it could be for undergraduate

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students in those subjects. But it could also

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be useful for graduate students

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and even active researchers

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who might benefit from a refresher,

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on some of the interdisciplinary

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aspects of

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this work. For instance,

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a radio biology researcher might want some basics

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on the relevant astrophysics

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and the nature of the origins of the

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radiation that they're studying.

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Similarly,

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astronomers might seek some basics on

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radiation science, radiation chemistry,

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and the biological

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effects

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of the radiation that stems from the astrophysical

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phenomenon that they study, such as solar flares,

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supernovas,

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gamma ray bursts, and related events.

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Okay. So so on that note, let's let's

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move on to the key themes in the

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book.

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Can you briefly describe the main sources of

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space radiation?

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Sure. I don't know about briefly explaining them,

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but,

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basically,

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some of the sources of radiation,

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that

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come from outer space and affect us here

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on Earth include cosmic rays.

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And, cosmic rays are charged particles. They're atomic

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nuclei ranging from ranging from,

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protons, which are hydrogen nuclei, all the way

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up to uranium

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nuclei.

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These cosmic rays can be classified as

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primary cosmic rays

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that come from the sun and beyond our

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solar system,

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and secondary cosmic rays that stem from spallation,

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which is the shattering

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of atomic nuclei

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in our atmosphere after they are struck by

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the speeding primaries.

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The secondary cosmic rays

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spread out in our atmosphere far and wide,

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kinda like a shotgun

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as opposed to the,

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the laser

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like or rifle bullet nature of the original

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incoming primary cosmic ray. So while primary cosmic

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rays are atomic nuclei,

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secondary cosmic rays are

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smaller atomic nuclei, protons, neutrons,

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pions,

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muons, and other entities.

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Here at the surface, most of the cosmic

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radiation that we are exposed to is in

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the form of muons, which can be thought

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of as

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the big brother of the electron,

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since muons are about 200 times as massive

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as electrons but are otherwise very similar.

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They're both,

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negatively charged leptons.

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The muons can arise through the decay of

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pions, which were formed even higher in the

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atmosphere, but decay extremely rapidly

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and can't reach our surface.

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But thanks to the slightly longer half life

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of the muons

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and

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the time dilatation

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of special relativity,

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some muons do make it here to the

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surface.

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Another way of classifying cosmic rays is through

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their site of origin.

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Cosmic, rays sent come some cosmic rays come

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from the sun and

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others come from beyond the solar system. Those

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coming from beyond the solar system are collectively

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called galactic cosmic rays.

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But the the name galactic cosmic rays may

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be a bit too restrictive

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since some of the ultra high energy

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cosmic rays,

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which

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get to phenomenal energies,

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10 to the 18th

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e v, for instance,

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seem to, originate from beyond our Milky Way

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galaxy altogether.

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So the the solar charge particles come in

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4 from 4 basic sources.

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There's

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a steady but low energy

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solar wind,

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then there are sporadic

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explosions on the sun that release large amounts

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of energy

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in the form of solar prominences,

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coronal mass ejections, and solar flares.

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But our atmosphere is able to attenuate

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most of this cosmic radiation,

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and our geomagnetic

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field

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deflects a large fraction of the incoming cosmic

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rays,

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because they are charged particles, and they are

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influenced by magnetic fields, including our geomagnetic

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fields. So just as electrons, protons, and carbon

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ions

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that are used in medical radiation therapy and

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produced,

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by linear accelerators,

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cyclotrons, and synchrotrons,

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the earth's geomagnetic

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field is able to deflect these

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incoming charged particles

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and,

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and,

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protect us that way.

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But this deflection

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leads to another

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source of radiation,

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the Van Allen belts. The Van Allen belts

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are 2 radiation belts

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made of trapped charged particles.

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They're arranged around the earth like giant donuts

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or bagels

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with the earth in the center.

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The outer belt is where the most energetic

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electrons reside,

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and the inner belt is where the most

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energetic protons live.

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Some of the protons in this

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inner Van Allen belt are produced through a

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process called CRAN,

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c r a n d, or cosmic ray

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albedo neutron decay.

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So like I said before, incoming primary cosmic

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rays smash into atmospheric molecules

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and atoms and shatter their nuclei through spallation.

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When this happens,

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free neutrons can be liberated.

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Free neutrons are unstable.

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They decay with a half life of around

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10 minutes, and the decay products include

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high energy protons.

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The high energy protons get accelerated to even

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higher energies, get trapped in the Van Allen

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belt,

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and contribute to the, that,

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the source of protons there.

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And on rare occasions, there could even be

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a third,

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Van Allen belt. This can happen after severe

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space weather like coronal

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mass ejections,

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And the 3rd belt is transient, typically lasting

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just a few weeks or so,

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and there's probably a splitting of the outer

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belt.

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I just read recently that a third belt,

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may have formed earlier this month.

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And another

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oddity about the Van Allen belts is the

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presence of antimatter.

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Among the, the truly exotic radiation species in

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00:11:42,129 --> 00:11:43,910
the Van Allen belts are,

287
00:11:44,370 --> 00:11:44,870
antiprotons.

288
00:11:45,524 --> 00:11:47,764
So we've learned a great deal about the

289
00:11:47,764 --> 00:11:50,264
Earth's radiation belts through NASA's,

290
00:11:51,045 --> 00:11:54,404
Van Allen probes, and we continue learning more

291
00:11:54,404 --> 00:11:56,485
each and every year. That's a long winded

292
00:11:56,485 --> 00:11:58,504
way of saying that the three main sources

293
00:11:58,929 --> 00:12:02,450
of space radiation in our vicinity are solar

294
00:12:02,450 --> 00:12:05,649
cosmic rays, galactic cosmic rays, and the Van

295
00:12:05,649 --> 00:12:08,870
Allen Belts. But beyond our local environment

296
00:12:09,250 --> 00:12:11,170
here in the solar system, there are numerous

297
00:12:11,170 --> 00:12:11,910
other weird

298
00:12:12,335 --> 00:12:14,995
exotic sources of radiation such as supernovas,

299
00:12:15,615 --> 00:12:19,315
soft gamma repeaters, gamma ray bursts, x-ray pulsers,

300
00:12:20,254 --> 00:12:22,735
the Fermi bubbles, and a host of other

301
00:12:22,735 --> 00:12:24,750
oddities that are discussed in the text.

302
00:12:25,309 --> 00:12:27,409
What are the main health issues associated

303
00:12:27,710 --> 00:12:30,049
with the exposure to all this space radiation?

304
00:12:30,669 --> 00:12:32,830
So that's an important question, and it is

305
00:12:32,830 --> 00:12:35,490
a a main topic of the text.

306
00:12:36,110 --> 00:12:37,745
Of course, whole body

307
00:12:38,445 --> 00:12:42,144
radiation exposure to any form of penetrating ionizing

308
00:12:42,365 --> 00:12:42,865
radiation

309
00:12:43,325 --> 00:12:46,365
can be hazardous and could even lead to

310
00:12:46,365 --> 00:12:49,004
acute radiation syndrome as the if the dose

311
00:12:49,004 --> 00:12:49,825
is high enough.

312
00:12:50,285 --> 00:12:51,585
And given the

313
00:12:51,889 --> 00:12:54,690
high energy of cosmic rays, which can get

314
00:12:54,690 --> 00:12:56,870
well into the, well above

315
00:12:57,889 --> 00:13:01,190
the GEV and even TEV range and higher,

316
00:13:01,490 --> 00:13:04,210
this form of radiation is very penetrating. And

317
00:13:04,210 --> 00:13:04,695
since

318
00:13:05,095 --> 00:13:06,154
atomic nuclei

319
00:13:06,615 --> 00:13:07,754
are highly charged,

320
00:13:08,535 --> 00:13:11,035
these cosmic rays are highly ionizing.

321
00:13:11,735 --> 00:13:13,995
So acute radiation syndrome

322
00:13:14,375 --> 00:13:15,595
is certainly possible,

323
00:13:15,975 --> 00:13:16,475
and

324
00:13:16,855 --> 00:13:20,470
acute radiation syndrome can be fatal. So awareness

325
00:13:20,470 --> 00:13:22,730
of this space radiation is important.

326
00:13:23,190 --> 00:13:23,690
But

327
00:13:24,230 --> 00:13:27,290
the reality is that here on Earth's surface,

328
00:13:27,750 --> 00:13:28,970
we're well protected

329
00:13:29,430 --> 00:13:32,570
from this. Our atmosphere and our geomagnetic

330
00:13:32,950 --> 00:13:33,450
field

331
00:13:33,975 --> 00:13:36,075
absorb or deflect a lot of the radiation.

332
00:13:36,134 --> 00:13:38,714
And at sea level, at most places,

333
00:13:39,014 --> 00:13:40,235
depending on the latitude,

334
00:13:40,615 --> 00:13:43,014
the higher the latitude, the more radiation we

335
00:13:43,014 --> 00:13:43,995
get from space,

336
00:13:44,534 --> 00:13:45,514
because of the

337
00:13:45,870 --> 00:13:48,929
the channeling and funneling of these charged particles

338
00:13:48,990 --> 00:13:51,870
by our magnetic poles. But depending on the

339
00:13:51,870 --> 00:13:52,370
latitude,

340
00:13:53,149 --> 00:13:57,330
space radiation contributes to about 0.3, maybe 0.4

341
00:13:57,470 --> 00:13:57,970
millisieverts

342
00:13:58,350 --> 00:14:00,750
per year or 30 to 40 millirem per

343
00:14:00,750 --> 00:14:01,995
year to use the older units.

344
00:14:04,454 --> 00:14:06,235
This is generally inconsequential

345
00:14:06,855 --> 00:14:08,634
in terms of its health impact.

346
00:14:09,254 --> 00:14:09,754
But

347
00:14:10,454 --> 00:14:12,235
interestingly, there are times

348
00:14:12,855 --> 00:14:15,495
when the dose here on the surface could

349
00:14:15,495 --> 00:14:16,235
be significantly

350
00:14:16,615 --> 00:14:19,360
higher. For example, when the north and south

351
00:14:19,360 --> 00:14:19,860
poles,

352
00:14:21,120 --> 00:14:23,860
reverse their polarity and the geomagnetic

353
00:14:24,399 --> 00:14:26,259
field transiently collapses.

354
00:14:26,799 --> 00:14:30,579
This happens on average now about every 200,

355
00:14:30,639 --> 00:14:31,139
300000

356
00:14:31,759 --> 00:14:32,259
years,

357
00:14:32,664 --> 00:14:34,504
But the last time this happened was the

358
00:14:34,504 --> 00:14:36,044
so called Brunus Macayama

359
00:14:36,664 --> 00:14:38,605
reversal. That was about 780,000

360
00:14:39,945 --> 00:14:40,684
years ago,

361
00:14:41,065 --> 00:14:43,565
and so we're well past due now.

362
00:14:44,105 --> 00:14:45,404
And by some estimates,

363
00:14:46,269 --> 00:14:49,389
when this happens, the weakened magnetic field might

364
00:14:49,389 --> 00:14:52,049
fall to only about 10% of its original

365
00:14:52,110 --> 00:14:52,610
strength,

366
00:14:53,230 --> 00:14:55,889
and this might last for about a century

367
00:14:55,950 --> 00:14:56,690
or so.

368
00:14:57,789 --> 00:15:01,045
But that's, here on Earth. Out in space,

369
00:15:01,045 --> 00:15:01,545
astronauts

370
00:15:02,004 --> 00:15:02,504
who,

371
00:15:03,524 --> 00:15:05,605
are out there are exposed to a lot

372
00:15:05,605 --> 00:15:07,845
more radiation than we'll ever be here on

373
00:15:07,845 --> 00:15:09,625
the surface, regardless of

374
00:15:09,925 --> 00:15:10,425
geomagnetic

375
00:15:10,804 --> 00:15:11,285
field,

376
00:15:11,684 --> 00:15:12,004
and,

377
00:15:12,644 --> 00:15:13,465
and atmosphere.

378
00:15:15,690 --> 00:15:18,429
In addition to the constant low level,

379
00:15:19,769 --> 00:15:23,210
radiation from galactic cosmic ray exposure and the

380
00:15:23,210 --> 00:15:26,509
solar winds, astronauts in space could be exposed

381
00:15:26,730 --> 00:15:29,230
to and at the mercy of high dose

382
00:15:29,290 --> 00:15:30,590
unpredictable solar

383
00:15:30,975 --> 00:15:33,375
particle events that are caused by things like

384
00:15:33,375 --> 00:15:34,674
coronal mass ejections

385
00:15:35,054 --> 00:15:36,274
or solar flares.

386
00:15:36,654 --> 00:15:38,914
If astronauts were out on a spacewalk

387
00:15:39,294 --> 00:15:41,714
during a strong solar particle event,

388
00:15:42,575 --> 00:15:46,070
they could get significant and potentially dangerous doses

389
00:15:46,070 --> 00:15:46,929
of radiation.

390
00:15:47,710 --> 00:15:49,330
But even in

391
00:15:50,590 --> 00:15:53,629
outer space, depending on the dose and depending

392
00:15:53,629 --> 00:15:54,769
on the dose rate,

393
00:15:55,230 --> 00:15:57,009
I don't think that this radiation

394
00:15:58,545 --> 00:16:01,285
is really as harmful as one might expect.

395
00:16:01,825 --> 00:16:03,205
In fact, one of the

396
00:16:03,665 --> 00:16:07,205
most fascinating topics that's being researched right now

397
00:16:07,745 --> 00:16:08,245
is,

398
00:16:08,705 --> 00:16:09,205
further

399
00:16:10,159 --> 00:16:11,539
investigation and evaluation,

400
00:16:12,559 --> 00:16:14,740
of the so called adaptive response.

401
00:16:15,600 --> 00:16:16,659
In this model,

402
00:16:17,199 --> 00:16:18,819
small doses of radiation

403
00:16:19,360 --> 00:16:22,639
serve as a primer that prepares the body,

404
00:16:22,639 --> 00:16:23,940
so to speak, for

405
00:16:24,365 --> 00:16:25,264
larger, otherwise

406
00:16:26,284 --> 00:16:29,105
hazardous doses of radiation. It's as if the

407
00:16:29,245 --> 00:16:31,725
the small dose gears the body up for

408
00:16:31,725 --> 00:16:34,284
a subsequent high dose challenge so that the

409
00:16:34,284 --> 00:16:35,024
high dose

410
00:16:35,325 --> 00:16:37,084
is no longer as dangerous as it would

411
00:16:37,084 --> 00:16:37,904
have been otherwise.

412
00:16:38,549 --> 00:16:40,730
This is sometimes called the, Yanazawa

413
00:16:41,029 --> 00:16:41,529
effect,

414
00:16:42,070 --> 00:16:42,470
and,

415
00:16:43,350 --> 00:16:44,649
that's one of the fascinating,

416
00:16:45,669 --> 00:16:48,470
subjects that I and others are studying. Another

417
00:16:48,470 --> 00:16:50,309
thing that we're studying is,

418
00:16:51,750 --> 00:16:53,370
based on some of the observations

419
00:16:54,105 --> 00:16:56,684
coming from the so called NASA twin study,

420
00:16:57,144 --> 00:16:57,884
in which,

421
00:16:59,384 --> 00:17:01,945
Scott Kelly stayed on board the ISS for

422
00:17:01,945 --> 00:17:04,424
about a year, International Space Station for about

423
00:17:04,424 --> 00:17:07,529
a year, while his identical twin brother, Mark

424
00:17:07,690 --> 00:17:10,029
Kelly, remained on Earth during that same period,

425
00:17:10,170 --> 00:17:11,230
and some fascinating

426
00:17:11,930 --> 00:17:14,029
biological changes were noticed

427
00:17:14,410 --> 00:17:17,070
in areas such as Scott's microbiome

428
00:17:17,930 --> 00:17:20,990
and, most curiously, in my opinion, in chromosomal

429
00:17:21,289 --> 00:17:23,474
telomere lanes. Since telomeres

430
00:17:24,095 --> 00:17:25,075
tend to progressively

431
00:17:26,015 --> 00:17:28,434
shorten with age and serve as biological

432
00:17:28,815 --> 00:17:29,315
clocks,

433
00:17:30,015 --> 00:17:33,134
and since radiation is considered to accelerate the

434
00:17:33,134 --> 00:17:34,194
aging process,

435
00:17:34,619 --> 00:17:37,740
it was really surprising to see that Scott's

436
00:17:37,740 --> 00:17:38,240
telomeres

437
00:17:38,619 --> 00:17:40,319
seem to actually lengthen

438
00:17:40,619 --> 00:17:43,339
relative to his brother, Marx, during this year

439
00:17:43,339 --> 00:17:45,900
in space. This is the opposite of what,

440
00:17:46,654 --> 00:17:48,494
might have been predicted. I like to call

441
00:17:48,494 --> 00:17:49,794
it a twin paradox

442
00:17:50,095 --> 00:17:52,255
of another sort. It's not the one that

443
00:17:52,255 --> 00:17:54,894
we learn about in school when we're studying

444
00:17:54,894 --> 00:17:55,875
special relativity.

445
00:17:56,414 --> 00:17:56,654
But,

446
00:17:58,095 --> 00:17:58,914
but confusingly,

447
00:18:00,335 --> 00:18:01,234
his telomeres

448
00:18:02,529 --> 00:18:05,410
shortened back to the normal anticipated length after

449
00:18:05,410 --> 00:18:06,710
he returned to earth.

450
00:18:07,250 --> 00:18:10,130
So the implications on health and longevity are

451
00:18:10,130 --> 00:18:12,150
still unknown, but the initial results

452
00:18:12,609 --> 00:18:13,750
seem reassuring.

453
00:18:14,769 --> 00:18:15,269
And

454
00:18:15,744 --> 00:18:18,544
importantly, I say that they assuaged the fears

455
00:18:18,544 --> 00:18:20,625
that otherwise might be faced by,

456
00:18:21,025 --> 00:18:22,644
astronauts Tooney Williams

457
00:18:23,025 --> 00:18:26,784
and but Butch Wilmore, who are presently on

458
00:18:26,784 --> 00:18:27,845
the ISS

459
00:18:28,609 --> 00:18:31,109
and might have to wait on another another

460
00:18:31,330 --> 00:18:32,150
8 months

461
00:18:32,769 --> 00:18:33,809
to get the

462
00:18:34,289 --> 00:18:37,109
a ride back with SpaceX in early 2025.

463
00:18:38,450 --> 00:18:41,090
Yeah. I don't think that their health is

464
00:18:41,090 --> 00:18:44,265
gonna be compromised by this long duration trip,

465
00:18:45,704 --> 00:18:48,664
but, what was supposed to be an 8

466
00:18:48,664 --> 00:18:49,164
day,

467
00:18:50,265 --> 00:18:50,765
adventure

468
00:18:51,065 --> 00:18:53,005
is turning into an 8 months,

469
00:18:55,305 --> 00:18:58,285
episode in outer space. It's kinda a severe

470
00:18:58,424 --> 00:18:59,704
form of a modern,

471
00:19:00,420 --> 00:19:01,880
Gilligan's Island story.

472
00:19:02,259 --> 00:19:03,619
I was gonna ask you about, you know,

473
00:19:03,619 --> 00:19:05,460
that we've already got people living in space

474
00:19:05,460 --> 00:19:06,360
on the ISS

475
00:19:06,980 --> 00:19:09,320
and sort of how this space radiation

476
00:19:09,700 --> 00:19:10,840
affects them.

477
00:19:11,220 --> 00:19:13,539
Is there a time limit? You you said

478
00:19:13,539 --> 00:19:15,700
that, the astronauts were out there for a

479
00:19:15,700 --> 00:19:16,654
year. Is

480
00:19:17,355 --> 00:19:18,875
do we have a time limit to how

481
00:19:18,875 --> 00:19:21,115
long we let people live on the space

482
00:19:21,115 --> 00:19:21,615
station?

483
00:19:22,394 --> 00:19:24,095
Well, if we do,

484
00:19:24,634 --> 00:19:25,375
it remains

485
00:19:25,755 --> 00:19:26,255
unknown

486
00:19:26,715 --> 00:19:28,894
how long that duration might be.

487
00:19:29,299 --> 00:19:30,259
And one of the,

488
00:19:30,900 --> 00:19:33,240
the things that I'm most curious about

489
00:19:33,619 --> 00:19:35,559
is the adaptive response

490
00:19:36,019 --> 00:19:37,400
and the body's

491
00:19:37,859 --> 00:19:39,160
ability to repair

492
00:19:39,619 --> 00:19:42,359
biological damage induced by space radiation.

493
00:19:44,015 --> 00:19:44,515
Unlike

494
00:19:45,454 --> 00:19:45,954
electronics,

495
00:19:47,214 --> 00:19:47,714
which

496
00:19:48,255 --> 00:19:51,934
if damaged by radiation cannot repair themselves for

497
00:19:51,934 --> 00:19:52,835
the most part,

498
00:19:53,375 --> 00:19:55,954
cells, tissues, organs, and organisms

499
00:19:56,730 --> 00:19:57,390
are capable

500
00:19:58,250 --> 00:19:58,829
of effecting,

501
00:20:01,210 --> 00:20:01,710
repair

502
00:20:02,250 --> 00:20:03,069
of damaged

503
00:20:03,450 --> 00:20:03,950
DNA,

504
00:20:04,490 --> 00:20:04,990
proteins,

505
00:20:05,609 --> 00:20:06,109
membranes,

506
00:20:06,410 --> 00:20:06,910
lipids,

507
00:20:07,690 --> 00:20:08,190
enzymes,

508
00:20:08,569 --> 00:20:10,269
or replace those damaged

509
00:20:12,524 --> 00:20:14,065
entities if necessary.

510
00:20:14,444 --> 00:20:14,944
That's

511
00:20:15,404 --> 00:20:16,304
a key difference

512
00:20:16,605 --> 00:20:17,105
between

513
00:20:17,644 --> 00:20:19,744
biological entities and inanimate

514
00:20:20,204 --> 00:20:23,644
objects. And that's why I'm not convinced at

515
00:20:23,644 --> 00:20:24,944
this time that

516
00:20:26,159 --> 00:20:28,799
the duration is gonna be very short. I

517
00:20:28,799 --> 00:20:31,359
think that the, the limit, if there is

518
00:20:31,359 --> 00:20:31,859
one,

519
00:20:32,319 --> 00:20:33,279
might be quite,

520
00:20:33,839 --> 00:20:34,659
quite lengthy

521
00:20:35,599 --> 00:20:38,295
in healthy individuals who are capable of

522
00:20:38,775 --> 00:20:39,275
repairing,

523
00:20:40,375 --> 00:20:41,994
DNA in a normal fashion.

524
00:20:42,695 --> 00:20:44,934
Are there ways that we can things that

525
00:20:44,934 --> 00:20:46,394
we can do to help protect

526
00:20:46,934 --> 00:20:47,994
the space travelers,

527
00:20:49,575 --> 00:20:53,730
via perhaps shielding or even sort of radio

528
00:20:53,730 --> 00:20:54,789
protector agents?

529
00:20:55,809 --> 00:20:56,309
Sure.

530
00:20:58,049 --> 00:20:59,269
Radiation protectors

531
00:20:59,650 --> 00:21:00,150
are,

532
00:21:01,250 --> 00:21:03,170
one of the things one of the topics

533
00:21:03,170 --> 00:21:04,309
that are being investigated

534
00:21:05,265 --> 00:21:06,724
intensely at this time.

535
00:21:07,265 --> 00:21:08,884
And among the,

536
00:21:10,144 --> 00:21:11,285
novel radiation

537
00:21:11,825 --> 00:21:12,325
protectors

538
00:21:12,705 --> 00:21:13,445
being investigated

539
00:21:14,224 --> 00:21:15,125
is apigenin.

540
00:21:17,025 --> 00:21:17,525
Apigenin

541
00:21:18,210 --> 00:21:19,349
and other polyphenols,

542
00:21:20,450 --> 00:21:21,269
like curcumin,

543
00:21:23,009 --> 00:21:25,429
work through a variety of different mechanisms

544
00:21:26,529 --> 00:21:29,250
and work through mechanisms that differ from some

545
00:21:29,250 --> 00:21:30,150
of the classic

546
00:21:31,169 --> 00:21:31,669
entities,

547
00:21:32,565 --> 00:21:33,625
such as amiphosphine.

548
00:21:34,404 --> 00:21:34,904
Amiphosphine

549
00:21:35,284 --> 00:21:37,065
works as a salt hydrol

550
00:21:37,365 --> 00:21:37,865
containing

551
00:21:38,724 --> 00:21:39,224
radiation

552
00:21:40,644 --> 00:21:42,024
free radical scavenger.

553
00:21:42,644 --> 00:21:43,144
But,

554
00:21:45,284 --> 00:21:46,184
these polyphenols

555
00:21:46,724 --> 00:21:47,544
work through

556
00:21:48,410 --> 00:21:49,309
different mechanisms,

557
00:21:49,690 --> 00:21:50,190
including,

558
00:21:51,450 --> 00:21:54,029
one of the mechanisms that we were surprised

559
00:21:54,089 --> 00:21:55,230
to observe ourselves,

560
00:21:55,609 --> 00:21:57,309
which is a modification

561
00:21:57,849 --> 00:21:59,309
of the gut microbiome.

562
00:22:00,494 --> 00:22:00,994
And

563
00:22:03,134 --> 00:22:03,634
radiation

564
00:22:04,095 --> 00:22:05,154
can alter

565
00:22:05,615 --> 00:22:06,595
the gut microbiome

566
00:22:07,295 --> 00:22:09,875
leading to what we call gut dysbiosis.

567
00:22:10,974 --> 00:22:12,835
And it appears that

568
00:22:13,695 --> 00:22:15,714
apigenin and probably other

569
00:22:16,019 --> 00:22:16,519
polyphenols

570
00:22:16,820 --> 00:22:18,119
and other agents

571
00:22:18,580 --> 00:22:22,359
are able to effectively reverse this gut dysbiosis

572
00:22:22,820 --> 00:22:23,559
and restore

573
00:22:24,019 --> 00:22:25,240
gut microbiome

574
00:22:25,859 --> 00:22:26,359
balance,

575
00:22:26,740 --> 00:22:27,240
which

576
00:22:27,619 --> 00:22:29,880
probably is helpful in recovery

577
00:22:30,420 --> 00:22:34,024
of radiation damage from the organismal level. This

578
00:22:34,024 --> 00:22:36,845
is a topic that hasn't really been actively

579
00:22:36,984 --> 00:22:39,085
investigated up until this point.

580
00:22:39,464 --> 00:22:39,964
So

581
00:22:40,345 --> 00:22:41,244
in the past,

582
00:22:42,664 --> 00:22:44,440
most of the the

583
00:22:44,740 --> 00:22:47,859
radiation protecting agents have been examined on the

584
00:22:47,859 --> 00:22:51,400
molecular and cellular level, but we now appreciate

585
00:22:51,539 --> 00:22:53,779
a bit better that, you have to look

586
00:22:53,779 --> 00:22:56,359
at the whole organism, and the whole organism

587
00:22:56,500 --> 00:22:57,000
includes

588
00:22:58,075 --> 00:22:59,134
gut microbiota

589
00:23:00,154 --> 00:23:03,035
that may be affected by radiation. And if,

590
00:23:03,515 --> 00:23:04,335
if dysbiosis

591
00:23:04,795 --> 00:23:05,295
occurs,

592
00:23:05,835 --> 00:23:07,215
balance may be reestablished

593
00:23:08,875 --> 00:23:09,275
by,

594
00:23:09,755 --> 00:23:11,375
agents such as apogenin.

595
00:23:13,119 --> 00:23:15,039
Okay. And then looking at sort of the

596
00:23:15,039 --> 00:23:16,180
idea of shielding,

597
00:23:17,279 --> 00:23:19,700
I see that the NASA Artemis missions

598
00:23:20,079 --> 00:23:22,259
include returning to the moon and even,

599
00:23:22,799 --> 00:23:24,880
they have a proposal for a lunar space

600
00:23:24,880 --> 00:23:25,380
station.

601
00:23:26,054 --> 00:23:28,474
I would imagine living on the moon, perhaps

602
00:23:28,534 --> 00:23:30,875
the risks from radiation will be greater.

603
00:23:31,414 --> 00:23:33,575
How could they sort of create the shielding

604
00:23:33,575 --> 00:23:35,914
required to protect people living there?

605
00:23:36,615 --> 00:23:36,934
So,

606
00:23:38,500 --> 00:23:39,799
yes, indeed. The,

607
00:23:40,179 --> 00:23:41,000
the shielding

608
00:23:41,380 --> 00:23:42,279
on the moon

609
00:23:42,819 --> 00:23:45,380
and on Mars and in deep space would

610
00:23:45,380 --> 00:23:46,839
have to be far different

611
00:23:47,299 --> 00:23:48,440
from the shielding

612
00:23:48,980 --> 00:23:51,240
even on the International Space Station

613
00:23:51,619 --> 00:23:52,119
because

614
00:23:53,365 --> 00:23:55,144
the International Space Station

615
00:23:55,845 --> 00:23:56,345
is,

616
00:23:58,484 --> 00:23:59,865
on average about 250

617
00:24:00,404 --> 00:24:03,065
miles above the Earth's surface, and

618
00:24:03,765 --> 00:24:05,464
that puts it well above

619
00:24:05,924 --> 00:24:07,419
the the troposphere

620
00:24:07,720 --> 00:24:10,279
and the stratosphere and even the mesosphere, but

621
00:24:10,279 --> 00:24:10,779
technically,

622
00:24:11,160 --> 00:24:13,019
it's still within the atmosphere

623
00:24:13,640 --> 00:24:14,519
orbiting in the,

624
00:24:15,000 --> 00:24:16,619
in the the, thermosphere.

625
00:24:17,480 --> 00:24:17,980
And

626
00:24:18,279 --> 00:24:18,779
while

627
00:24:19,640 --> 00:24:20,460
there's no,

628
00:24:22,095 --> 00:24:22,595
significant

629
00:24:23,375 --> 00:24:23,875
atmospheric

630
00:24:24,174 --> 00:24:25,875
friction at that level,

631
00:24:26,494 --> 00:24:27,234
it's still

632
00:24:28,095 --> 00:24:28,595
within

633
00:24:28,894 --> 00:24:29,795
the atmosphere

634
00:24:30,174 --> 00:24:30,914
and still

635
00:24:31,934 --> 00:24:33,955
within the confines and the protection

636
00:24:34,529 --> 00:24:36,150
of the, the geomagnetic

637
00:24:36,690 --> 00:24:39,809
field. There's no significant amounts of air that

638
00:24:39,809 --> 00:24:43,109
are attenuating the radiation above, but the geomagnetic

639
00:24:43,490 --> 00:24:45,910
field does offer some deflective

640
00:24:46,210 --> 00:24:46,710
protection.

641
00:24:47,265 --> 00:24:49,984
That is all lost when you're beyond the

642
00:24:49,984 --> 00:24:50,484
geomagnetic

643
00:24:50,785 --> 00:24:51,285
field

644
00:24:51,744 --> 00:24:53,285
and, in interplanetary

645
00:24:53,904 --> 00:24:56,384
space or on the moon or on Mars,

646
00:24:56,384 --> 00:24:59,445
which does not have a significant atmosphere or

647
00:24:59,505 --> 00:25:01,445
magnetic field for shielding.

648
00:25:02,089 --> 00:25:02,910
And therefore,

649
00:25:04,570 --> 00:25:07,549
radiation protectors become more important biologically,

650
00:25:08,170 --> 00:25:10,349
shielding becomes more important,

651
00:25:12,410 --> 00:25:13,309
for astronauts

652
00:25:13,769 --> 00:25:14,269
and

653
00:25:14,570 --> 00:25:15,470
in the future

654
00:25:15,934 --> 00:25:16,434
maybe

655
00:25:16,815 --> 00:25:17,315
exploration

656
00:25:18,174 --> 00:25:18,674
and

657
00:25:19,015 --> 00:25:19,515
exploitation

658
00:25:19,855 --> 00:25:20,355
of

659
00:25:22,654 --> 00:25:26,434
geological phenomenon or structures such as lava tubes,

660
00:25:26,575 --> 00:25:28,674
which could serve as shelters

661
00:25:29,160 --> 00:25:29,660
if,

662
00:25:30,359 --> 00:25:33,480
a radiation event is on its way. Then

663
00:25:33,480 --> 00:25:37,340
maybe, these would become more important to avail,

664
00:25:37,960 --> 00:25:39,019
ourselves of.

665
00:25:39,480 --> 00:25:42,220
You mentioned briefly as well how radiation can

666
00:25:42,519 --> 00:25:43,660
impact electronics.

667
00:25:45,005 --> 00:25:47,325
Is this a problem for current space travel

668
00:25:47,325 --> 00:25:49,505
or perhaps for future long duration

669
00:25:49,964 --> 00:25:50,464
missions?

670
00:25:51,085 --> 00:25:51,585
Both.

671
00:25:52,204 --> 00:25:52,704
So,

672
00:25:53,964 --> 00:25:54,784
like I said,

673
00:25:55,325 --> 00:25:56,544
biological entities

674
00:25:57,119 --> 00:25:58,019
such as cells,

675
00:25:58,960 --> 00:26:02,660
and tissues are capable of of repair

676
00:26:03,039 --> 00:26:06,099
of damaged DNA or disposal and,

677
00:26:06,480 --> 00:26:06,980
replacement

678
00:26:07,599 --> 00:26:07,920
of,

679
00:26:08,400 --> 00:26:10,259
irreparably damaged enzymes.

680
00:26:11,154 --> 00:26:13,654
Electronic equipment, for the most part, is

681
00:26:14,674 --> 00:26:15,575
unable to

682
00:26:16,355 --> 00:26:19,015
affect its own repair. And therefore,

683
00:26:21,954 --> 00:26:23,095
many of the electronic

684
00:26:23,474 --> 00:26:23,974
devices

685
00:26:24,275 --> 00:26:26,320
have to be so called hardened

686
00:26:26,779 --> 00:26:27,759
against radiation.

687
00:26:28,059 --> 00:26:29,980
One of the things that's very interesting to

688
00:26:29,980 --> 00:26:31,359
me is the fact that

689
00:26:31,740 --> 00:26:33,519
electronic radiation hardening

690
00:26:34,619 --> 00:26:37,980
is studied and investigated in-depth and and,

691
00:26:38,460 --> 00:26:38,960
tested

692
00:26:39,325 --> 00:26:41,505
at radiotherapy facilities because

693
00:26:41,805 --> 00:26:43,805
after all, if much of the space radiation

694
00:26:43,805 --> 00:26:45,265
is in the form of protons,

695
00:26:45,565 --> 00:26:47,105
and we use protons,

696
00:26:47,484 --> 00:26:47,984
for,

697
00:26:48,684 --> 00:26:49,664
cancer radiotherapy,

698
00:26:50,365 --> 00:26:51,105
those facilities

699
00:26:51,484 --> 00:26:53,025
are a gold mine for

700
00:26:53,440 --> 00:26:55,700
conducting tests on hardened,

701
00:26:56,720 --> 00:26:57,220
electronics.

702
00:26:57,840 --> 00:26:58,340
So,

703
00:26:59,519 --> 00:27:01,299
the computer hardware,

704
00:27:01,759 --> 00:27:02,900
electronic hardware

705
00:27:03,359 --> 00:27:06,660
must be hardened against, space radiation,

706
00:27:07,519 --> 00:27:07,680
and,

707
00:27:08,559 --> 00:27:11,434
this could become a limiting factor. So I

708
00:27:11,434 --> 00:27:12,575
do believe that,

709
00:27:14,394 --> 00:27:16,174
now and in the future,

710
00:27:16,954 --> 00:27:18,734
it's not going to be

711
00:27:19,274 --> 00:27:19,774
the

712
00:27:21,434 --> 00:27:22,174
the biological

713
00:27:22,474 --> 00:27:24,335
consequences of space radiation

714
00:27:24,849 --> 00:27:26,389
so much as the,

715
00:27:28,450 --> 00:27:28,950
durability

716
00:27:30,210 --> 00:27:31,669
of our electronics

717
00:27:31,970 --> 00:27:32,629
and computers

718
00:27:33,329 --> 00:27:35,250
in the long term. So if we were

719
00:27:35,250 --> 00:27:38,450
to go on a long term deep space

720
00:27:38,450 --> 00:27:39,429
mission where,

721
00:27:40,055 --> 00:27:41,434
like in the science fiction

722
00:27:41,815 --> 00:27:42,315
stories,

723
00:27:42,694 --> 00:27:44,875
people are put into suspended animation

724
00:27:45,255 --> 00:27:46,954
for years on end.

725
00:27:47,575 --> 00:27:49,734
I don't think that it's gonna be the

726
00:27:49,734 --> 00:27:50,234
radiation

727
00:27:50,855 --> 00:27:52,634
effect on the biology

728
00:27:53,015 --> 00:27:55,700
of the people so much as the radiation

729
00:27:55,759 --> 00:27:58,019
effect on the electronics and computers

730
00:27:58,559 --> 00:28:01,779
that proves to be the, the limiting factor.

731
00:28:04,160 --> 00:28:04,900
In fact,

732
00:28:05,519 --> 00:28:08,079
if you recall the, the great Arthur c

733
00:28:08,079 --> 00:28:08,579
Clark

734
00:28:09,105 --> 00:28:10,325
book and movie,

735
00:28:10,785 --> 00:28:12,305
2001, a space odyssey,

736
00:28:13,025 --> 00:28:16,865
I think the computer, Hal, goes nuts and,

737
00:28:17,345 --> 00:28:18,565
becomes a homicidal

738
00:28:18,865 --> 00:28:21,045
maniac and kills the astronauts.

739
00:28:21,769 --> 00:28:24,329
Literary experts always tell me that, oh, you

740
00:28:24,329 --> 00:28:26,329
know, this is a great allegory. Arthur c

741
00:28:26,329 --> 00:28:27,849
Clark was talking about,

742
00:28:28,329 --> 00:28:31,950
how the conflict in Hal's mind about him,

743
00:28:32,569 --> 00:28:33,390
having to,

744
00:28:37,005 --> 00:28:37,904
be subservient

745
00:28:38,284 --> 00:28:39,664
to these intellectually

746
00:28:40,044 --> 00:28:43,644
inferior humans or the fact that he wasn't

747
00:28:43,644 --> 00:28:45,825
fully told about the real

748
00:28:46,284 --> 00:28:46,784
underlying

749
00:28:47,960 --> 00:28:49,019
cause of the mission.

750
00:28:49,559 --> 00:28:51,559
The the main purpose of the mission led

751
00:28:51,559 --> 00:28:53,099
to some psychic

752
00:28:53,799 --> 00:28:55,740
conflict, and he broke down.

753
00:28:56,119 --> 00:28:59,000
Nah. In my opinion, nobody was talking about

754
00:28:59,000 --> 00:29:00,700
the fact that they were near Jupiter,

755
00:29:01,294 --> 00:29:05,214
and Jupiter has intense radiation belts that put

756
00:29:05,214 --> 00:29:07,775
our Van Allen belts to shame, and he

757
00:29:07,775 --> 00:29:09,954
just suffered from radiation sickness

758
00:29:10,335 --> 00:29:12,275
and went crazy for that reason.

759
00:29:12,815 --> 00:29:14,680
But that's just my interpretation.

760
00:29:15,460 --> 00:29:17,940
Excellent. That's really interesting. I mean, you've you

761
00:29:17,940 --> 00:29:20,339
kind of answered my final question, which was,

762
00:29:20,339 --> 00:29:21,240
you know, looking

763
00:29:21,539 --> 00:29:23,799
beyond the moon to Mars or long distance

764
00:29:23,859 --> 00:29:24,359
travel.

765
00:29:24,820 --> 00:29:28,019
Will space radiation be the limiting factor in

766
00:29:28,019 --> 00:29:29,595
how far we can explore?

767
00:29:30,154 --> 00:29:32,075
I was asking that from the point of

768
00:29:32,075 --> 00:29:34,394
view of, you know, the human body, but

769
00:29:34,394 --> 00:29:36,255
perhaps, like you say, it will be the

770
00:29:36,634 --> 00:29:38,654
electronics that's the limiting factor.

771
00:29:39,355 --> 00:29:41,194
I think it could be at this point.

772
00:29:41,194 --> 00:29:41,694
So,

773
00:29:42,474 --> 00:29:43,375
in my opinion,

774
00:29:45,809 --> 00:29:46,950
radiation biology

775
00:29:47,250 --> 00:29:50,630
is a fascinating subject and is very different

776
00:29:51,089 --> 00:29:54,069
from space electronics and computer hardware

777
00:29:54,529 --> 00:29:55,029
electronics

778
00:29:55,410 --> 00:29:56,150
in that

779
00:29:57,315 --> 00:30:01,315
cells and biological molecules are capable of being

780
00:30:01,315 --> 00:30:02,934
replaced or repaired,

781
00:30:03,394 --> 00:30:06,214
and the current generation of electronics

782
00:30:06,515 --> 00:30:06,994
is not,

783
00:30:08,434 --> 00:30:09,255
self repairing.

784
00:30:09,634 --> 00:30:12,214
But perhaps that could be something that

785
00:30:12,690 --> 00:30:14,849
will be affected by,

786
00:30:15,809 --> 00:30:19,490
by artificial intelligence as it detects damage to

787
00:30:19,490 --> 00:30:19,990
itself

788
00:30:20,369 --> 00:30:22,389
and directs its own repair.

789
00:30:22,849 --> 00:30:25,190
So perhaps there could be interesting

790
00:30:26,714 --> 00:30:30,095
horizons that, have never been considered before.

791
00:30:30,954 --> 00:30:32,875
Thanks very much for joining us today in

792
00:30:32,875 --> 00:30:34,734
discussing this fascinating subject.

793
00:30:35,355 --> 00:30:37,355
If listeners want to find out more, I'd

794
00:30:37,355 --> 00:30:39,509
recommend taking a look at James' ebook.

795
00:30:39,910 --> 00:30:41,450
It can be found on the IOPscience

796
00:30:41,829 --> 00:30:42,329
website,

797
00:30:42,630 --> 00:30:45,210
and it's part of the IPEM IOP series

798
00:30:45,349 --> 00:30:47,849
in Physics and Engineering in Medicine and Biology.

799
00:30:48,630 --> 00:30:51,130
Thanks again, James, for speaking with us today.

800
00:30:51,190 --> 00:30:53,109
Well, thank you very much, Tammy. It's been

801
00:30:53,109 --> 00:30:53,769
a pleasure.

802
00:31:02,065 --> 00:31:05,585
That was Tammy Freeman in conversation with James

803
00:31:05,585 --> 00:31:06,085
Welsh,

804
00:31:06,464 --> 00:31:08,964
the author of Space Radiation,

805
00:31:10,009 --> 00:31:10,509
Astrophysical

806
00:31:10,970 --> 00:31:11,470
Origins,

807
00:31:12,169 --> 00:31:12,669
Radiobiological

808
00:31:13,690 --> 00:31:14,190
Effects,

809
00:31:14,490 --> 00:31:15,470
and the Implications

810
00:31:16,009 --> 00:31:17,230
for Space Travelers.

811
00:31:17,690 --> 00:31:18,750
Global navigation

812
00:31:19,210 --> 00:31:21,710
satellite systems such as GPS

813
00:31:22,404 --> 00:31:23,224
have revolutionized

814
00:31:23,684 --> 00:31:25,865
how we get around on Earth.

815
00:31:26,565 --> 00:31:28,884
As well as telling us exactly where we

816
00:31:28,884 --> 00:31:29,384
are,

817
00:31:29,765 --> 00:31:31,704
the atomic clock precision

818
00:31:32,164 --> 00:31:33,944
of GPS time signals

819
00:31:34,404 --> 00:31:36,505
have a wide range of applications,

820
00:31:37,549 --> 00:31:40,369
including the coordination of telecoms

821
00:31:40,670 --> 00:31:41,170
networks,

822
00:31:42,029 --> 00:31:44,769
energy grids, and financial markets.

823
00:31:45,630 --> 00:31:48,349
Humans look set to return to the moon

824
00:31:48,349 --> 00:31:49,065
very shortly,

825
00:31:49,625 --> 00:31:52,924
and the creation and operation of lunar bases

826
00:31:53,304 --> 00:31:54,524
and other infrastructure

827
00:31:55,065 --> 00:31:57,004
would benefit from a universal

828
00:31:57,384 --> 00:31:58,284
time system

829
00:31:58,984 --> 00:32:00,904
just like the one we have here on

830
00:32:00,904 --> 00:32:01,404
Earth.

831
00:32:01,944 --> 00:32:04,589
To find out more, I caught up with

832
00:32:04,589 --> 00:32:07,330
Neil Ashby and Biju Patla

833
00:32:07,710 --> 00:32:11,250
of the National Institute of Standards and Technology

834
00:32:11,630 --> 00:32:12,529
in the US.

835
00:32:13,309 --> 00:32:16,049
They've written a paper called a Relativistic

836
00:32:16,589 --> 00:32:17,089
Framework

837
00:32:17,565 --> 00:32:20,304
to estimate clock rates on the moon,

838
00:32:20,605 --> 00:32:23,005
and they join me down the line from

839
00:32:23,005 --> 00:32:24,224
Boulder, Colorado.

840
00:32:31,960 --> 00:32:34,619
Hi Bijou and Neil. Welcome to the podcast.

841
00:32:35,799 --> 00:32:37,340
Thank you for having us

842
00:32:37,720 --> 00:32:38,779
on your podcast.

843
00:32:39,480 --> 00:32:41,660
So my first question is

844
00:32:41,960 --> 00:32:44,440
why would it be useful to create a

845
00:32:44,440 --> 00:32:46,380
lunar standard time

846
00:32:46,795 --> 00:32:49,115
as opposed to using a time signal from

847
00:32:49,115 --> 00:32:49,615
Earth,

848
00:32:50,154 --> 00:32:51,375
when you're on the moon?

849
00:32:51,674 --> 00:32:52,174
Well,

850
00:32:52,555 --> 00:32:53,055
we're,

851
00:32:53,595 --> 00:32:54,974
at a stage where

852
00:32:55,275 --> 00:32:56,815
people are envisioning,

853
00:32:58,394 --> 00:33:00,015
a much larger presence

854
00:33:00,390 --> 00:33:03,190
of humans on the moon and robots as

855
00:33:03,190 --> 00:33:03,690
well.

856
00:33:04,150 --> 00:33:06,089
So if there are many assets

857
00:33:06,390 --> 00:33:08,410
on and near the moon,

858
00:33:08,869 --> 00:33:10,089
then they would

859
00:33:10,390 --> 00:33:10,890
saturate

860
00:33:11,509 --> 00:33:12,250
the communications

861
00:33:12,710 --> 00:33:13,210
channels,

862
00:33:14,549 --> 00:33:17,345
between the moon and the earth. And so,

863
00:33:18,285 --> 00:33:20,464
it's it's better to have an independent,

864
00:33:22,525 --> 00:33:23,025
time

865
00:33:23,404 --> 00:33:24,785
system for navigation

866
00:33:25,565 --> 00:33:26,464
near the moon,

867
00:33:27,724 --> 00:33:29,484
so that one does not have to worry

868
00:33:29,484 --> 00:33:29,984
about

869
00:33:30,759 --> 00:33:34,200
communications problems with the earth, and as well

870
00:33:34,200 --> 00:33:35,740
as the time delay

871
00:33:36,119 --> 00:33:36,619
between,

872
00:33:37,480 --> 00:33:39,720
what happens on the moon and the,

873
00:33:40,119 --> 00:33:40,619
news

874
00:33:41,000 --> 00:33:43,724
that that has happened that arrives at the

875
00:33:43,724 --> 00:33:44,224
Earth.

876
00:33:45,484 --> 00:33:48,065
And and in your recent work, you also

877
00:33:48,285 --> 00:33:49,164
talk about,

878
00:33:49,964 --> 00:33:52,125
time dilation, which is a which is a

879
00:33:52,125 --> 00:33:52,625
relativistic

880
00:33:53,005 --> 00:33:53,505
effect.

881
00:33:53,884 --> 00:33:55,025
The fact that,

882
00:33:55,805 --> 00:33:56,545
a clock

883
00:33:56,924 --> 00:33:58,285
on the moon would run

884
00:33:58,819 --> 00:34:01,640
is it faster than a clock on Earth?

885
00:34:02,099 --> 00:34:04,200
It would that affect how

886
00:34:04,579 --> 00:34:06,599
timekeeping is done on the moon?

887
00:34:06,900 --> 00:34:09,559
And, you you know, any sort of comparisons

888
00:34:09,699 --> 00:34:11,719
to to clocks on Earth?

889
00:34:13,619 --> 00:34:14,675
Yeah. Yeah.

890
00:34:15,055 --> 00:34:16,675
The clocks on the moon

891
00:34:17,135 --> 00:34:20,335
tend to run faster because they'll they're away

892
00:34:20,335 --> 00:34:21,315
from the Earth.

893
00:34:21,614 --> 00:34:24,195
And Earth is a heavier object, and so

894
00:34:24,735 --> 00:34:27,375
heavier objects slows down time. And so moon

895
00:34:27,375 --> 00:34:29,375
is away from the Earth, so the time

896
00:34:29,375 --> 00:34:31,989
ticks, clocks tick faster there.

897
00:34:32,929 --> 00:34:33,429
But

898
00:34:33,730 --> 00:34:35,109
the main reason

899
00:34:35,489 --> 00:34:38,530
why we need to know the difference, the

900
00:34:38,530 --> 00:34:39,510
rate offset

901
00:34:40,369 --> 00:34:42,550
between these two bodies is

902
00:34:43,644 --> 00:34:46,364
that the command and control of all the

903
00:34:46,364 --> 00:34:46,864
operations,

904
00:34:47,404 --> 00:34:49,505
robotic operations on the moon,

905
00:34:50,204 --> 00:34:51,184
is on earth.

906
00:34:52,045 --> 00:34:53,505
So we would want to

907
00:34:54,444 --> 00:34:54,944
local

908
00:34:56,284 --> 00:34:57,744
transfer all the local

909
00:34:58,579 --> 00:35:01,480
information on the moon to the earth,

910
00:35:02,099 --> 00:35:03,480
using a broadband

911
00:35:04,420 --> 00:35:05,239
and a communication

912
00:35:05,940 --> 00:35:07,480
line. And so

913
00:35:07,940 --> 00:35:11,880
the time stamping of information is essential in

914
00:35:12,085 --> 00:35:13,945
the packets not being dropped.

915
00:35:14,405 --> 00:35:16,644
So that's why we have to synchronize the

916
00:35:16,644 --> 00:35:17,144
time

917
00:35:17,844 --> 00:35:20,485
and then use a common time so that

918
00:35:20,485 --> 00:35:23,204
the order of arrival and transmission back and

919
00:35:23,204 --> 00:35:25,525
forth, you know, do not run into some

920
00:35:25,525 --> 00:35:28,930
causal issues with time and pack and resulting

921
00:35:28,930 --> 00:35:30,950
in packet losses and things like that.

922
00:35:31,329 --> 00:35:31,989
And also

923
00:35:32,369 --> 00:35:32,849
to,

924
00:35:33,250 --> 00:35:35,510
the previous point that Neil made,

925
00:35:36,369 --> 00:35:39,349
the why why we need a time,

926
00:35:40,210 --> 00:35:42,194
for the moon of its own. So

927
00:35:42,815 --> 00:35:43,315
imagine

928
00:35:44,335 --> 00:35:45,554
there are so many,

929
00:35:46,174 --> 00:35:48,194
you know, robots or,

930
00:35:49,054 --> 00:35:52,255
electronic devices on the moon. Every electronic device

931
00:35:52,255 --> 00:35:54,594
has a oscillator, a clock in it.

932
00:35:55,054 --> 00:35:56,755
And so the local

933
00:35:58,079 --> 00:35:58,900
clocks there

934
00:35:59,519 --> 00:36:03,300
tend to be showing the natural time of

935
00:36:03,360 --> 00:36:05,920
the of the moon lunar surface, and that

936
00:36:05,920 --> 00:36:07,300
is different than the Earth.

937
00:36:07,840 --> 00:36:08,660
And so

938
00:36:09,200 --> 00:36:11,380
it is easier to have

939
00:36:12,014 --> 00:36:13,074
robotic communication

940
00:36:14,014 --> 00:36:17,135
and GPS like system on the moon to

941
00:36:17,135 --> 00:36:19,614
use the lunar time because the assets will

942
00:36:19,614 --> 00:36:21,394
be running on the moon time.

943
00:36:21,855 --> 00:36:24,815
And then if we extend this time to

944
00:36:24,815 --> 00:36:28,250
everywhere around the moon, then you have established

945
00:36:28,469 --> 00:36:29,610
a common time.

946
00:36:30,070 --> 00:36:31,869
And once you have the time and this

947
00:36:31,869 --> 00:36:34,170
is the common time in the physics textbooks

948
00:36:34,710 --> 00:36:35,449
when you,

949
00:36:35,909 --> 00:36:39,210
learn about time and space. The time axis,

950
00:36:39,269 --> 00:36:40,784
that is a coordinate time.

951
00:36:41,264 --> 00:36:43,344
So, essentially, this is a time that we

952
00:36:43,344 --> 00:36:45,184
want to have. And so that we can

953
00:36:45,184 --> 00:36:47,605
solve the navigation equations and then

954
00:36:48,704 --> 00:36:49,204
locate,

955
00:36:49,585 --> 00:36:50,565
you know, different,

956
00:36:51,424 --> 00:36:53,585
assets. And, you know, they then they can

957
00:36:53,585 --> 00:36:54,085
just,

958
00:36:55,079 --> 00:36:58,460
help with the PNT position navigation and timing

959
00:36:58,760 --> 00:36:59,579
on these,

960
00:37:00,920 --> 00:37:02,940
I know, these celestial bodies.

961
00:37:04,280 --> 00:37:05,340
And and so

962
00:37:05,640 --> 00:37:07,820
how how would we go about creating

963
00:37:08,335 --> 00:37:10,894
a lunar standard? I mean, here on Earth,

964
00:37:11,535 --> 00:37:13,155
we use atomic clocks,

965
00:37:13,695 --> 00:37:16,195
both on the Earth and also in orbit

966
00:37:16,494 --> 00:37:18,035
to create sort of a network

967
00:37:18,574 --> 00:37:20,114
of of very accurate

968
00:37:20,460 --> 00:37:20,960
timekeepers.

969
00:37:21,420 --> 00:37:22,780
Would we do the same,

970
00:37:23,179 --> 00:37:25,039
on on the moon? Would we replace

971
00:37:25,340 --> 00:37:27,739
atomic clocks on the moon and and perhaps

972
00:37:27,739 --> 00:37:28,239
also

973
00:37:28,619 --> 00:37:31,519
at Earth Moon Lagrange points,

974
00:37:32,539 --> 00:37:34,480
to to sort of afford

975
00:37:34,875 --> 00:37:37,855
the communication of time between Earth and moon?

976
00:37:38,875 --> 00:37:41,355
Yes. You would have assets on the moon's

977
00:37:41,355 --> 00:37:41,855
surface

978
00:37:42,554 --> 00:37:45,375
and also in orbit around the moon.

979
00:37:45,755 --> 00:37:48,094
Because if you have an asset in orbit,

980
00:37:48,389 --> 00:37:51,289
you can cover more of the moon's surface

981
00:37:51,909 --> 00:37:52,409
than,

982
00:37:53,109 --> 00:37:55,449
than if if you have a fixed asset,

983
00:37:56,309 --> 00:37:57,529
on the moon's surface.

984
00:37:58,389 --> 00:37:59,529
Lagrange points

985
00:38:00,069 --> 00:38:01,529
might not be usable

986
00:38:01,829 --> 00:38:02,809
in this way

987
00:38:03,644 --> 00:38:05,025
because they're so far

988
00:38:05,405 --> 00:38:07,265
from the Earth and the moon.

989
00:38:07,885 --> 00:38:09,585
It's more likely you would want,

990
00:38:10,765 --> 00:38:13,744
something in orbit around the moon. The Lagrange

991
00:38:13,804 --> 00:38:16,065
points, like l4 and l5

992
00:38:16,969 --> 00:38:17,469
are,

993
00:38:19,130 --> 00:38:20,889
are so far that they're more likely to

994
00:38:20,889 --> 00:38:22,109
be used as communication

995
00:38:23,130 --> 00:38:23,630
links,

996
00:38:24,489 --> 00:38:26,030
between the Earth and the moon.

997
00:38:27,449 --> 00:38:30,089
There's one Lagrange point between the Earth and

998
00:38:30,089 --> 00:38:30,750
the moon,

999
00:38:32,525 --> 00:38:33,025
which,

1000
00:38:33,804 --> 00:38:35,424
which would be subject to,

1001
00:38:36,364 --> 00:38:36,864
interference,

1002
00:38:38,525 --> 00:38:41,005
with direct communication between the moon and the

1003
00:38:41,005 --> 00:38:41,505
Earth.

1004
00:38:42,364 --> 00:38:45,489
Summarizing, I think, it's it's that you want

1005
00:38:45,789 --> 00:38:47,089
assets on the moon

1006
00:38:47,389 --> 00:38:47,889
surface

1007
00:38:48,589 --> 00:38:49,089
and,

1008
00:38:50,030 --> 00:38:51,969
widely distributed if possible,

1009
00:38:52,269 --> 00:38:53,010
and assets,

1010
00:38:54,750 --> 00:38:56,449
in orbit around the moon.

1011
00:38:57,924 --> 00:38:59,764
And and today, there, you know, there are

1012
00:38:59,764 --> 00:39:01,224
lots of atomic clocks,

1013
00:39:01,684 --> 00:39:04,164
in orbit. You know, that's that's what makes

1014
00:39:04,164 --> 00:39:05,304
GPS work.

1015
00:39:06,565 --> 00:39:08,505
So would it be fairly straightforward

1016
00:39:08,964 --> 00:39:09,464
to,

1017
00:39:10,005 --> 00:39:11,704
to put atomic clocks

1018
00:39:12,099 --> 00:39:14,760
on the moon, seeing that we we've already

1019
00:39:15,139 --> 00:39:17,460
put them into space? Or or would you

1020
00:39:17,460 --> 00:39:19,639
have to or are there other considerations

1021
00:39:20,099 --> 00:39:21,699
that that you would have to deal with

1022
00:39:21,699 --> 00:39:22,199
before

1023
00:39:22,579 --> 00:39:24,359
you could build such a network?

1024
00:39:25,844 --> 00:39:27,864
Well, I think there are space qualified,

1025
00:39:28,485 --> 00:39:31,125
atomic clocks available. Some of them off the

1026
00:39:31,125 --> 00:39:32,585
shelf, like, rubidium

1027
00:39:33,204 --> 00:39:33,704
clocks

1028
00:39:34,164 --> 00:39:36,885
are generally available. They would probably have to

1029
00:39:36,885 --> 00:39:37,625
be modified,

1030
00:39:39,789 --> 00:39:41,489
because they would now be

1031
00:39:42,589 --> 00:39:45,309
so far from the earth rather than rather

1032
00:39:45,309 --> 00:39:46,130
than a few

1033
00:39:46,589 --> 00:39:49,489
1000 miles or kilometers. They would be

1034
00:39:50,030 --> 00:39:52,429
100 of 1000 of kilometers away from the

1035
00:39:52,429 --> 00:39:54,914
earth. So the antennas would have to be

1036
00:39:55,375 --> 00:39:56,434
probably redesigned,

1037
00:39:58,175 --> 00:40:00,974
and other modifications would probably have to be

1038
00:40:00,974 --> 00:40:01,474
made.

1039
00:40:02,094 --> 00:40:04,675
So one of the main roadblocks or constraints

1040
00:40:04,894 --> 00:40:06,114
is the power requirement

1041
00:40:06,730 --> 00:40:09,309
for, running this operation from the moon.

1042
00:40:10,570 --> 00:40:11,070
And

1043
00:40:11,450 --> 00:40:11,950
so

1044
00:40:12,329 --> 00:40:13,710
right now, it

1045
00:40:14,969 --> 00:40:17,869
the agencies like NASA have a staggered approach.

1046
00:40:18,410 --> 00:40:20,349
1 is to test a demonstration,

1047
00:40:21,974 --> 00:40:23,114
in the near term

1048
00:40:23,574 --> 00:40:24,074
with,

1049
00:40:25,335 --> 00:40:28,234
oscillator or crystal oscillator and similar,

1050
00:40:28,614 --> 00:40:29,755
you know, oscillators

1051
00:40:30,534 --> 00:40:32,954
and use them as clocks and then

1052
00:40:33,255 --> 00:40:35,034
just demo it from

1053
00:40:35,344 --> 00:40:35,844
send

1054
00:40:36,819 --> 00:40:38,839
the earth time there and,

1055
00:40:39,699 --> 00:40:40,199
downlink,

1056
00:40:40,500 --> 00:40:43,000
the moon time using a two way communication.

1057
00:40:43,699 --> 00:40:45,480
It's, it's it's, satellite

1058
00:40:45,780 --> 00:40:47,000
communication channels.

1059
00:40:48,019 --> 00:40:50,760
And that is a technology demonstration mission,

1060
00:40:51,885 --> 00:40:52,605
kind of,

1061
00:40:52,925 --> 00:40:54,945
type of thing. And next would be,

1062
00:40:55,405 --> 00:40:57,824
a combination of clocks as Neil suggested

1063
00:40:58,605 --> 00:40:59,425
with rubidium,

1064
00:40:59,724 --> 00:41:00,224
cesium,

1065
00:41:00,844 --> 00:41:03,659
and aggregate it, and then keep track of

1066
00:41:03,819 --> 00:41:06,000
the Earth and the moon time differences,

1067
00:41:06,539 --> 00:41:09,579
and then beam the moon time back into

1068
00:41:09,579 --> 00:41:10,639
cislunar space,

1069
00:41:11,179 --> 00:41:13,039
and then use that for,

1070
00:41:14,139 --> 00:41:14,639
recreating

1071
00:41:15,019 --> 00:41:16,159
GPS like

1072
00:41:16,585 --> 00:41:17,085
environment,

1073
00:41:18,025 --> 00:41:18,905
on the moon

1074
00:41:19,224 --> 00:41:20,525
around moon 2.

1075
00:41:20,985 --> 00:41:21,644
And also,

1076
00:41:22,184 --> 00:41:23,724
for the Lagrange points,

1077
00:41:24,425 --> 00:41:25,164
are necessary

1078
00:41:28,679 --> 00:41:31,239
there is you cannot use it just like

1079
00:41:31,239 --> 00:41:32,699
a point. You have to,

1080
00:41:33,639 --> 00:41:36,519
define orbit around it, and they can be

1081
00:41:36,519 --> 00:41:38,460
from fairly large orbits,

1082
00:41:39,000 --> 00:41:39,659
in cases.

1083
00:41:40,519 --> 00:41:41,659
Mostly, they,

1084
00:41:42,679 --> 00:41:43,179
some

1085
00:41:43,594 --> 00:41:45,534
satellites are parked there

1086
00:41:45,835 --> 00:41:46,974
as a relay.

1087
00:41:47,914 --> 00:41:49,934
So if you want to extend

1088
00:41:50,234 --> 00:41:50,734
the

1089
00:41:51,034 --> 00:41:52,094
Earth's infrastructure

1090
00:41:52,795 --> 00:41:54,815
out into the cislunar space,

1091
00:41:55,514 --> 00:41:57,375
you can imagine these as

1092
00:41:57,890 --> 00:42:01,250
space or a setting up communication towers or,

1093
00:42:01,250 --> 00:42:04,210
like, for the cell phone situation on earth

1094
00:42:04,210 --> 00:42:06,150
where there are big towers and then,

1095
00:42:06,849 --> 00:42:09,910
they relay and and sync with each other.

1096
00:42:10,255 --> 00:42:13,135
And so using Lagrange points, you can get

1097
00:42:13,135 --> 00:42:13,795
a full

1098
00:42:14,175 --> 00:42:14,675
view

1099
00:42:15,295 --> 00:42:16,014
the of,

1100
00:42:16,494 --> 00:42:17,295
the Earth,

1101
00:42:17,775 --> 00:42:19,554
moon, and everywhere else.

1102
00:42:20,255 --> 00:42:21,875
So that is, networking

1103
00:42:22,760 --> 00:42:23,639
and, relaying,

1104
00:42:25,000 --> 00:42:25,719
type of,

1105
00:42:27,639 --> 00:42:28,139
setup.

1106
00:42:29,159 --> 00:42:30,440
I see. And,

1107
00:42:30,760 --> 00:42:32,780
you you've already touched on how,

1108
00:42:33,159 --> 00:42:34,539
this lunar timekeeping

1109
00:42:34,920 --> 00:42:36,219
system could be used.

1110
00:42:37,114 --> 00:42:37,775
I mean,

1111
00:42:38,155 --> 00:42:39,614
I'm sort of thinking the 2

1112
00:42:40,074 --> 00:42:41,835
main applications would be,

1113
00:42:42,635 --> 00:42:43,614
sort of coordinating

1114
00:42:44,074 --> 00:42:46,014
communication systems, coordinating

1115
00:42:46,954 --> 00:42:50,360
robots, as you mentioned. But would also a

1116
00:42:50,360 --> 00:42:52,780
sort of a lunar GPS system

1117
00:42:53,480 --> 00:42:54,860
be possible where,

1118
00:42:55,400 --> 00:42:57,739
you could you could accurately,

1119
00:42:58,519 --> 00:42:59,019
locate,

1120
00:43:00,360 --> 00:43:03,099
robotic systems, for example, or even human

1121
00:43:03,744 --> 00:43:06,005
explorers on the surface of the moon?

1122
00:43:07,344 --> 00:43:08,324
Yes. It's entirely

1123
00:43:09,025 --> 00:43:11,844
feasible and and most likely would will happen

1124
00:43:12,224 --> 00:43:12,724
ultimately.

1125
00:43:14,304 --> 00:43:16,405
If you have, lots of assets

1126
00:43:17,059 --> 00:43:17,880
on the moon,

1127
00:43:18,340 --> 00:43:19,639
whether they'd be robotic,

1128
00:43:20,659 --> 00:43:21,960
or or human,

1129
00:43:23,139 --> 00:43:23,639
assets,

1130
00:43:24,980 --> 00:43:26,119
you want to avoid

1131
00:43:27,619 --> 00:43:28,119
collisions.

1132
00:43:28,905 --> 00:43:30,585
You want to be able to go back

1133
00:43:30,585 --> 00:43:33,244
to the same place. For example, if you're

1134
00:43:34,184 --> 00:43:34,684
exploring

1135
00:43:35,065 --> 00:43:36,765
for minerals or water,

1136
00:43:37,625 --> 00:43:38,765
or something else,

1137
00:43:39,625 --> 00:43:41,724
and you find something that's interesting,

1138
00:43:42,339 --> 00:43:44,659
you may not have all of the all

1139
00:43:44,659 --> 00:43:45,480
of the tools

1140
00:43:45,940 --> 00:43:48,659
or instruments you need to investigate. So you

1141
00:43:48,659 --> 00:43:50,500
want to be able to go back to

1142
00:43:50,500 --> 00:43:54,099
the base and get it and and return

1143
00:43:54,099 --> 00:43:55,319
to the same spot.

1144
00:43:55,744 --> 00:43:57,364
So you need accurate

1145
00:43:57,905 --> 00:43:58,405
navigation.

1146
00:43:59,105 --> 00:44:00,785
And for that, you need to you need

1147
00:44:00,785 --> 00:44:02,785
to be able to be in the line

1148
00:44:02,785 --> 00:44:05,344
of sight of a number of assets that

1149
00:44:05,344 --> 00:44:06,085
have clocks.

1150
00:44:07,730 --> 00:44:10,369
I see. And and, you know, the moon,

1151
00:44:10,369 --> 00:44:12,710
I suppose, is is on the near horizon.

1152
00:44:13,730 --> 00:44:17,409
NASA is very keen on on returning to

1153
00:44:17,409 --> 00:44:20,049
the moon very shortly. But what what about

1154
00:44:20,049 --> 00:44:20,549
Mars?

1155
00:44:22,085 --> 00:44:24,804
For Mars ex exploration, I would imagine it's

1156
00:44:24,804 --> 00:44:27,144
it's that much further away from Earth.

1157
00:44:27,605 --> 00:44:30,324
Communicating back and forth between Mars and Earth

1158
00:44:30,324 --> 00:44:32,404
is is going to be difficult. There's gonna

1159
00:44:32,404 --> 00:44:34,484
be a big time lag. I would imagine

1160
00:44:34,484 --> 00:44:35,464
that a a

1161
00:44:35,789 --> 00:44:37,090
a time a Martian,

1162
00:44:37,869 --> 00:44:40,610
time system would would also be important.

1163
00:44:42,269 --> 00:44:44,289
And that's true. This is seen

1164
00:44:44,829 --> 00:44:47,570
over the long term as a step toward,

1165
00:44:48,875 --> 00:44:51,075
a test step toward the,

1166
00:44:51,954 --> 00:44:53,255
establishment of the independent

1167
00:44:53,555 --> 00:44:54,375
time system

1168
00:44:54,755 --> 00:44:55,494
or Mars.

1169
00:44:55,875 --> 00:44:57,974
And one could envision, in fact,

1170
00:44:58,835 --> 00:45:00,215
with assets around

1171
00:45:00,515 --> 00:45:02,994
planets like Venus, I doubt if there's ever

1172
00:45:02,994 --> 00:45:03,869
gonna be any,

1173
00:45:04,910 --> 00:45:06,450
any, human presence

1174
00:45:06,990 --> 00:45:08,930
or even robots much

1175
00:45:09,309 --> 00:45:10,690
on Venus or other,

1176
00:45:12,110 --> 00:45:13,010
other planets.

1177
00:45:13,630 --> 00:45:16,065
You could have assets in orbit

1178
00:45:17,184 --> 00:45:19,505
around other planets and have the independent time

1179
00:45:19,505 --> 00:45:20,005
systems

1180
00:45:20,385 --> 00:45:21,204
or positioning

1181
00:45:22,144 --> 00:45:22,885
and navigation

1182
00:45:23,264 --> 00:45:23,764
around

1183
00:45:24,385 --> 00:45:25,284
around them.

1184
00:45:26,224 --> 00:45:27,444
And and what about,

1185
00:45:28,304 --> 00:45:29,764
using these clocks

1186
00:45:30,869 --> 00:45:32,170
for for science,

1187
00:45:33,190 --> 00:45:34,809
you you know, rather than communications

1188
00:45:35,829 --> 00:45:36,650
and navigation?

1189
00:45:37,909 --> 00:45:40,309
Could, I mean, could could these clocks be

1190
00:45:40,309 --> 00:45:43,304
used to, I don't know, make more accurate

1191
00:45:43,445 --> 00:45:43,945
measurements

1192
00:45:44,244 --> 00:45:46,724
of the motions of the moon and the

1193
00:45:46,724 --> 00:45:46,965
planets,

1194
00:45:48,644 --> 00:45:49,144
and,

1195
00:45:49,684 --> 00:45:52,085
you know, tell us tell us something about

1196
00:45:52,085 --> 00:45:55,285
that? Or or would that require some some

1197
00:45:55,285 --> 00:45:56,425
very, very accurate

1198
00:45:57,900 --> 00:45:59,199
clocks that maybe

1199
00:45:59,500 --> 00:46:01,359
it wouldn't be possible to send,

1200
00:46:01,980 --> 00:46:03,359
to the moon or Mars?

1201
00:46:05,260 --> 00:46:06,400
It's it's possible,

1202
00:46:07,420 --> 00:46:08,719
but I think that,

1203
00:46:10,059 --> 00:46:13,184
in in talking about using them for science,

1204
00:46:13,184 --> 00:46:14,405
you're talking more

1205
00:46:15,184 --> 00:46:15,924
more about,

1206
00:46:17,025 --> 00:46:18,405
using them for scientific

1207
00:46:18,784 --> 00:46:20,324
investigations on the moon

1208
00:46:20,625 --> 00:46:23,204
or on Mars rather than rather than

1209
00:46:23,664 --> 00:46:24,324
the intrinsic

1210
00:46:25,000 --> 00:46:26,380
science of timekeeping,

1211
00:46:27,640 --> 00:46:29,900
which is which is not interesting,

1212
00:46:30,680 --> 00:46:31,180
but,

1213
00:46:32,280 --> 00:46:33,660
probably of a less,

1214
00:46:34,039 --> 00:46:35,019
of less interest.

1215
00:46:37,000 --> 00:46:37,739
I see.

1216
00:46:38,315 --> 00:46:40,315
Okay. So so would you be talking about

1217
00:46:40,315 --> 00:46:42,414
there, you know, for example, measuring,

1218
00:46:43,355 --> 00:46:45,695
making a very accurate measurement of the gravitational

1219
00:46:46,394 --> 00:46:48,655
field of the moon or Mars

1220
00:46:49,115 --> 00:46:50,335
using very

1221
00:46:51,090 --> 00:46:52,070
precise clocks,

1222
00:46:53,329 --> 00:46:55,730
and and learning something about the interior, for

1223
00:46:55,730 --> 00:46:56,230
example,

1224
00:46:56,610 --> 00:46:57,430
from that.

1225
00:46:59,809 --> 00:47:02,470
I think it's quite possible that that could

1226
00:47:02,610 --> 00:47:05,035
occur, but you would need what you need

1227
00:47:05,035 --> 00:47:05,355
is,

1228
00:47:06,074 --> 00:47:08,494
in times is that gives you very precise

1229
00:47:08,715 --> 00:47:09,215
positioning

1230
00:47:09,835 --> 00:47:12,655
so that you can study things like motion

1231
00:47:13,835 --> 00:47:16,579
of the surface of the moon or motion

1232
00:47:16,579 --> 00:47:17,880
of the surface of Mars.

1233
00:47:18,500 --> 00:47:19,159
For example,

1234
00:47:19,619 --> 00:47:20,920
one of the early

1235
00:47:21,940 --> 00:47:24,280
applications of GPS was to study

1236
00:47:24,739 --> 00:47:26,679
the motion of crustal plates

1237
00:47:27,460 --> 00:47:28,965
on the earth, which are

1238
00:47:30,644 --> 00:47:32,664
many thousands of kilometers apart,

1239
00:47:32,965 --> 00:47:33,945
but you could still

1240
00:47:34,244 --> 00:47:35,465
measure the motion,

1241
00:47:36,405 --> 00:47:38,344
of the order of a few centimeters

1242
00:47:38,644 --> 00:47:39,385
per year

1243
00:47:39,684 --> 00:47:42,260
using these systems. So you can get very

1244
00:47:42,260 --> 00:47:42,760
accurate,

1245
00:47:43,539 --> 00:47:44,039
measurements

1246
00:47:44,340 --> 00:47:45,079
of motion

1247
00:47:45,539 --> 00:47:48,039
of other objects using a very good,

1248
00:47:48,659 --> 00:47:50,440
positioning and timing system.

1249
00:47:51,139 --> 00:47:52,760
The first point is

1250
00:47:53,699 --> 00:47:55,835
the even on earth,

1251
00:47:56,614 --> 00:47:59,034
the best atomic clocks using,

1252
00:47:59,974 --> 00:48:01,355
the best atomic clock,

1253
00:48:01,974 --> 00:48:04,474
the geodesy and aspects like that

1254
00:48:05,414 --> 00:48:08,074
are still in the very nascent stages.

1255
00:48:08,429 --> 00:48:10,510
I mean, there is a possibility of doing

1256
00:48:10,510 --> 00:48:12,989
better measurements with good clock. And these are

1257
00:48:12,989 --> 00:48:14,130
very good clocks,

1258
00:48:14,989 --> 00:48:16,369
with very high stability,

1259
00:48:17,710 --> 00:48:20,050
at the 10 raise to minus 18 level.

1260
00:48:21,824 --> 00:48:23,045
Otherwise, mostly,

1261
00:48:23,824 --> 00:48:24,324
gravimeters

1262
00:48:24,864 --> 00:48:28,224
are used for mapping surfaces and, things like

1263
00:48:28,224 --> 00:48:28,724
that.

1264
00:48:29,025 --> 00:48:32,005
But for the moon, that having a good

1265
00:48:32,065 --> 00:48:35,684
time standard or local time for the moon

1266
00:48:36,410 --> 00:48:36,730
is,

1267
00:48:37,610 --> 00:48:40,190
is, especially useful for astronomy,

1268
00:48:40,970 --> 00:48:43,769
for the using them and, you know, other

1269
00:48:43,769 --> 00:48:44,989
dark side of the moon.

1270
00:48:45,610 --> 00:48:48,190
It's a very quiet environment for astronomers,

1271
00:48:49,275 --> 00:48:52,094
And, a certain very large baseline,

1272
00:48:52,954 --> 00:48:53,934
kind of experiments

1273
00:48:54,234 --> 00:48:55,775
can be done simultaneously

1274
00:48:56,155 --> 00:48:58,175
using the Earth and the moon locations,

1275
00:48:59,114 --> 00:48:59,594
for,

1276
00:49:01,835 --> 00:49:03,454
observation no astronomy.

1277
00:49:05,239 --> 00:49:05,980
For clocks

1278
00:49:06,519 --> 00:49:07,019
itself,

1279
00:49:07,800 --> 00:49:08,859
if you have,

1280
00:49:11,000 --> 00:49:13,639
excellent clocks, which I think would be a

1281
00:49:13,639 --> 00:49:14,139
little,

1282
00:49:14,839 --> 00:49:16,380
too soon at this time,

1283
00:49:17,434 --> 00:49:19,675
We would we would be looking at 10

1284
00:49:19,675 --> 00:49:20,974
raised to minus 16

1285
00:49:21,755 --> 00:49:23,135
ish stability clocks

1286
00:49:23,514 --> 00:49:24,894
because you need,

1287
00:49:25,514 --> 00:49:28,974
the the technology is not ready to launch

1288
00:49:29,114 --> 00:49:30,335
and operate,

1289
00:49:30,795 --> 00:49:33,440
some of the best clocks on earth in

1290
00:49:33,579 --> 00:49:34,400
these environments.

1291
00:49:35,739 --> 00:49:38,539
So but the time standard for the moon

1292
00:49:38,539 --> 00:49:40,000
using lunar gravity

1293
00:49:40,380 --> 00:49:41,839
is useful for,

1294
00:49:42,780 --> 00:49:43,760
other applications,

1295
00:49:45,099 --> 00:49:45,760
for astronomy.

1296
00:49:46,265 --> 00:49:48,364
Also, the link the communication

1297
00:49:48,824 --> 00:49:51,244
link between Earth and moon

1298
00:49:51,545 --> 00:49:53,324
would help a little bit

1299
00:49:53,625 --> 00:49:54,125
with,

1300
00:49:55,305 --> 00:49:55,885
you know,

1301
00:49:56,425 --> 00:49:58,230
equivalence principle kind of test

1302
00:49:59,030 --> 00:49:59,349
and,

1303
00:49:59,989 --> 00:50:02,469
aspects like that. But we already have the

1304
00:50:02,469 --> 00:50:02,969
retroreflectors

1305
00:50:03,989 --> 00:50:04,949
there, and,

1306
00:50:05,349 --> 00:50:08,070
we are shooting lasers from Earth here to

1307
00:50:08,070 --> 00:50:08,969
the moon back.

1308
00:50:09,349 --> 00:50:10,389
So I would

1309
00:50:11,109 --> 00:50:12,309
it it would help,

1310
00:50:13,030 --> 00:50:13,965
not as much

1311
00:50:14,445 --> 00:50:16,765
to further this cost because we already have

1312
00:50:16,765 --> 00:50:17,505
very good,

1313
00:50:18,445 --> 00:50:18,945
setup,

1314
00:50:19,724 --> 00:50:21,644
for the earth moon. But we can learn

1315
00:50:21,644 --> 00:50:22,305
a lot,

1316
00:50:23,005 --> 00:50:23,505
going,

1317
00:50:24,125 --> 00:50:24,864
from this,

1318
00:50:25,724 --> 00:50:28,139
to extend it to Mars and other,

1319
00:50:28,940 --> 00:50:29,440
future,

1320
00:50:30,460 --> 00:50:32,159
inner solar system exploration

1321
00:50:32,699 --> 00:50:35,019
would be this moon would be a stepping

1322
00:50:35,019 --> 00:50:36,799
stone in that sense for,

1323
00:50:37,339 --> 00:50:39,119
establishing a coordinate time

1324
00:50:39,420 --> 00:50:40,319
and doing

1325
00:50:42,905 --> 00:50:44,125
measuring local experiments

1326
00:50:44,505 --> 00:50:45,545
using, this,

1327
00:50:46,105 --> 00:50:46,605
constellation

1328
00:50:47,304 --> 00:50:49,644
GPS like constellation around the moon.

1329
00:50:50,105 --> 00:50:52,824
And with what we learn, we can, you

1330
00:50:52,824 --> 00:50:54,125
know, we can

1331
00:50:54,425 --> 00:50:56,630
extend it to other. So this would be

1332
00:50:56,630 --> 00:50:59,590
the first time that humans would do anything

1333
00:50:59,590 --> 00:51:00,250
like this,

1334
00:51:02,469 --> 00:51:04,390
away from the earth. And so that in

1335
00:51:04,390 --> 00:51:05,530
itself is a very,

1336
00:51:06,630 --> 00:51:07,110
new,

1337
00:51:07,590 --> 00:51:08,090
enterprise.

1338
00:51:09,184 --> 00:51:11,105
Yeah. That is I mean, it is very

1339
00:51:11,105 --> 00:51:12,644
exciting, isn't it, the idea

1340
00:51:13,265 --> 00:51:14,885
of putting precision timekeepers

1341
00:51:15,585 --> 00:51:16,405
on the moon?

1342
00:51:17,105 --> 00:51:19,664
So yeah. Thanks, Biju and Neil. Thanks for

1343
00:51:19,664 --> 00:51:20,804
coming on the podcast

1344
00:51:21,280 --> 00:51:23,539
and, and talking about your research.

1345
00:51:25,200 --> 00:51:25,860
You're welcome.

1346
00:51:26,400 --> 00:51:27,860
Thank you very much for

1347
00:51:28,480 --> 00:51:31,380
having us. It was a delight to explain

1348
00:51:32,000 --> 00:51:34,820
these notions of, you know, the time itself

1349
00:51:34,960 --> 00:51:37,074
having a change and the rate. Is hard

1350
00:51:37,074 --> 00:51:38,594
to conceive, but,

1351
00:51:39,474 --> 00:51:41,795
this would be a good demonstration. This is

1352
00:51:41,795 --> 00:51:44,275
the opposite of usually, people know about time

1353
00:51:44,275 --> 00:51:45,875
in the sense of going to the black

1354
00:51:45,875 --> 00:51:48,114
hole, but time slows down. This is the

1355
00:51:48,114 --> 00:51:50,135
opposite case where the time actually

1356
00:51:50,434 --> 00:51:51,574
is running faster.

1357
00:51:53,239 --> 00:51:53,800
So that

1358
00:51:54,840 --> 00:51:57,480
it's a very strange situation because because of

1359
00:51:57,480 --> 00:51:59,639
the earth, our time is slightly slower. So

1360
00:52:00,039 --> 00:52:01,980
Mhmm. So thank you for having us.

1361
00:52:02,280 --> 00:52:04,380
Yeah. It was my pleasure. Thanks, guys.

1362
00:52:10,894 --> 00:52:14,994
That was NIST's Biju Patla and Neil Ashby.

1363
00:52:15,535 --> 00:52:16,914
Their paper is published

1364
00:52:17,295 --> 00:52:18,275
in the Astronomical

1365
00:52:18,735 --> 00:52:21,315
Journal, and it's called a relativistic

1366
00:52:21,775 --> 00:52:22,275
framework

1367
00:52:22,750 --> 00:52:25,489
to estimate clock rates on the moon.

1368
00:52:25,869 --> 00:52:27,969
And you can find it at IOPscience.

1369
00:52:29,390 --> 00:52:31,230
I'm afraid that's all the time we have

1370
00:52:31,230 --> 00:52:32,450
for this week's podcast.

1371
00:52:32,829 --> 00:52:34,369
Thanks to James Welsh,

1372
00:52:34,750 --> 00:52:35,730
Neil Ashby,

1373
00:52:36,110 --> 00:52:39,505
Biju Patla, and Tammy Freeman for joining me

1374
00:52:39,505 --> 00:52:40,005
today.

1375
00:52:40,625 --> 00:52:42,945
We'll be back again next week when I'm

1376
00:52:42,945 --> 00:52:43,765
in conversation

1377
00:52:44,144 --> 00:52:45,125
with a physicist

1378
00:52:45,585 --> 00:52:48,405
who has won a King Charles the third

1379
00:52:48,704 --> 00:52:49,204
Coronation

1380
00:52:49,585 --> 00:52:51,844
medal for her outreach work.

1381
00:52:52,329 --> 00:52:55,050
And I also chat about the future of

1382
00:52:55,050 --> 00:52:55,550
graphene

1383
00:52:55,929 --> 00:52:58,190
with the director of the sustainable

1384
00:52:58,809 --> 00:52:59,309
advanced

1385
00:52:59,609 --> 00:53:00,109
materials

1386
00:53:00,569 --> 00:53:02,510
research group at Turkey's

1387
00:53:03,130 --> 00:53:03,630
Sabanciu

1388
00:53:04,409 --> 00:53:04,909
University.