Our universe is humming with gravitational waves

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Physics.

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World. Hello and welcome to the
Physics World Stories Podcast.

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I'm Andre Glasser,

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and although last month I did promise
you that we'd be looking at the

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international Year of basic
sciences for sustainability.

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Something has happened
in the world of physics,

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which has shifted that down the schedule
a bit. We will bring you that podcast.

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But on June the 29th, 2023,

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the North American Nano Hertz
Observatory for gravitational waves,

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otherwise known as Nano Graph,

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made a major announcement during a
live streamed event from the National

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Science Foundation.

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The official press release reads
astrophysicists using large radio

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telescopes to observe a collection
of cosmic clocks in our galaxy have

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found evidence for gravitational waves
that oscillate with periods of years

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to decades,

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according to a set of papers published
in the Astrophysical Journal.

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Letters from the press
conference. Here's Dr. Sean Jones,

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the assistant director for the Director
of Mathematical and Physical Sciences

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at the National Science Foundation.

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In 1995, the Hubble Space Telescope
revealed the Hubble Deep Field,

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a tiny sliver of the night sky brimming
with a veritable zoo of galaxies in

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various stages of evolution. In 2022,

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the James Webb Space Telescope refined
and deepened that image fantastically

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displaying galaxies more than 13
billion light years away from earth.

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Aided by the state-of-the-art optical
and infrared telescopes and decades of

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advancement and instrumentation
and data processing,

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we perceive a static
image of distant galaxies.

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Today's announcement
shatters that perception of a
static universe through the

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direct observation of gigantic
gravitational waves washing across our

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Milky Way galaxy, spawned by
cataclysmic events, including some,

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some from the most distant
regions of the cosmos.

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These observations reveal a rolling,

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noisy universe alive with a
cosmic symphony of gravitational

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waves.

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In the recent announcement,

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the nano graph team announced
the detection of shockwaves
from what they believe

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could be the merger of
super massive black holes.

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You may be thinking, hang on,

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didn't they already detect gravitational
waves at the Ligo Virgo observatories a

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few years ago? And if you've been
listening to this podcast for a few years,

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then you'll know that
they sounded like this.

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The difference here is that
rather than one-off events,

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nano graph has detected a consistent
hum triggered by gravitational

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waves.

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It could be the first direct
evidence of the stretching and

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squeezing of space time
due to black holes,

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and it opens a new window on
the universe speaking to physics

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world, his Ben Steppers from
the University of Manchester.

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The gravitational wave, um,

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is often referred to as
being a ripple in space time.

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So it's something which is
generated when, uh, well,

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it's most easily detected when you
have massive objects, for example,

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orbiting each other. And
so that generates a, a,

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a so-called ripple in space time. But
like if I throw a stone into a, uh,

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into a pond and you see the water ripples,
um, we have the equivalent of, uh,

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of what gravity does to a space time.

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Nano graphs started as a group of
about a dozen scientists back in

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2007. It's now grown to 194 members,

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including 77 graduate students
at over 80 institutions,

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not only in the US but around the world.

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Cherry Young was involved
in the early stages of nano.

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I am a radio astronomer,

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and my research interest is
in everything transient things

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that, um, uh,

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like explosions and fast
time scales or things like

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pulsars that we can
detect their, um, posters,

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radio posters very well using
radio telescope facilities. Uh,

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during my PhD,

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I've worked on a pulsar all
Skye blind search using the

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Australian Parks radio telescope,

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and then I moved to Canada
where I spent eight years, um,

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of my time on the Chime
radio telescope, uh,

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helping to commission this new facilities,

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which has led to a large
number of fast radio burst

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discoveries.

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And it is also involved
in Pulsar research. Uh,

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very recently moved to
France where I took up a

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permanent astronomer position
at the C N R S National Research

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Institute.

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And so I'm hoping to continue my
work on Pulsar Fast Radio Burst and

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set, as well as my
other research interest.

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I think we're need to
talk about those things,

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but maybe we'll talk about
them later because, um,

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there's a particular
topic for this podcast.

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The Pulsar Community.

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We are very excited to share with
the public the discovery wave of

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evidence of gravitational waves
from the Pulsar Timing experiment,

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basically using, uh,

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the fastest spinning millisecond pulsar
in a pulsar timing array experiment to

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detect gravitational waves. And
this is a really long time effort.

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We have been doing this
experiment for over a decade now.

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The idea is to observe an ensemble
of these millisecond pulsars,

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and they have extreme
rotational stability.

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We can pre predict the arrival
time of their pulses to a extremely

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high precision. Normally the pulses, um,

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stably ticking away that,

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but the idea is if there
is a gravitational wave,

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some distortion of the space time
in the background, we will see,

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uh, the arrival time of the pulsars
from a certain region of the sky.

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We'll see the pulses arriving
a bit earlier and maybe the,

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and the another direction of the sky
might be a bit later due to the passing of

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this gravitational wave
from the background.

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So the idea is to use
these pulsar pulsar pulses

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to, to work backwards to detect
the underlying gravitational waves.

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And after over a decade of analysis,

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we think we have finally reached the
significance threshold to say that we have

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seen the first evidence of these waves.

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Pulsars were first detected in
1967 by Northern Irish physicist

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Jocelyn Bell.

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You are probably familiar if you've been
listening to this podcast recently with

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the story of how she was
overlooked in the 1974 Nobel Prize,

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celebrating that discovery,

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which was shared by her supervisor
Anthony Hewish and the radio

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astronomer Martin Ryle.
That podcast, by the way,

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was the Physics World Stories
Podcast from back in May,

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in which we look at the impacts of the
Belbin El Graduate Scholarship Fund

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funded by money generously
donated by Jocelyn from prizes.

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She has subsequently won. I asked
Cherry to remind me what pulsars are.

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Uh, basically pulsars are
rapidly spinning neutron stars,

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and they, they are extremely
dense. Um, and they,

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they have a size of, um,

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a city like London, probab probably,
I would say the, the diameter,

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um, of a pulsar could
be the size of London,

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but it has the mass of mod,

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like one and a half times
our sun all squeezed into the

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size of London. So it's really dense.

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And this is what contributes to the very

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extreme rotational
stability. These pulsars, um,

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have emission coming from the two poles.

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And an interesting fact is that
the rotational axis and the

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emission axis are misaligned,

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just like how it is in a lighthouse,
if you know what that is.

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So as the pollar spins, we,

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we see a pulse when the emission
passes our line of sight.

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So this is what causes the, um,

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apparent pulsation. It doesn't mean the
side is pulsating, it's just rotating.

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And we see, um, the signal and
whenever it comes to us, us.

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Using pulsars for the detection
of gravitational waves,

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where's this fit in the
history of the hunt for them.

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The idea of gravitational
waves first brought up,

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it was by Einstein in 1916, right?
So that was really a long time ago.

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And although there has
been some proofs, um,

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so some evidence of
gravitational waves in the past,

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they were not the same as what
we have seen now with the postal

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timing wave. The first
proof of gravitational waves
was about 60 years after

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Einstein first talked about it.

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And that was from one
pulsar binary system.

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The astronomers realized that there is
a pulsar that is in a binary system with

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a white dwa and, uh, the, the fact
that they are operating each other,

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but as time goes by, they are getting
closer and closer to them, to each other,

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uh, at a rate predicted
by general relativity.

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If they are radiating gravitational
waves losing energy as they

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get closer to, to each
other. So this was, uh,

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an evidence of gravitational wave,

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but only indirectly because we could
only say on dance maybe the waves because

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the, the two objects are
getting closer to each other.

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It was however very exciting
and this analysis won

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a Nobel prize, um, as well.

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And then the next breakthrough
was from li g o, um,

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was also quite recent in the
last few, 2015 I believe,

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was when LIGO first detected gravitational
waves by two colliding still a mass

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black hole. How now, um,

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fast forward into 2023
posts are timing array

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has now contributed to yet and other
evidence of gravitational waste.

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But this time from, um,

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the pre-merger of super massive
black hole. So these are even more,

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um,

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much more massive objects
compared to what LIGO has seen.

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Super massive black hole as is named,
such as its name suggests, uh, really,

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really massive black holes. And, um,

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let's say they are sort of
millions to even billion times, um,

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the size of our sun.

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And we believe that in
the center of most galaxy,

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there should be a black hole and
throughout the cosmic history,

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galaxies merge and the black hole
in the center collide to form

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bigger galaxies and bigger black holes.

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And eventually we'll get to these
super massive monster black,

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black holes and they should
eventually merge as well. And the,

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the signals we are detecting from the
Pulsar timing array experiment is actually

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not from individual merger
because these events are

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from so far away.

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The amplitude of it is
really, really tiny.

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And what pulsar timing array we currently
has the ability to detect with belief

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at least is the, um,
background of these waves.

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That is the distortion
in space time caused by

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many of these supermassive
black hole pre-merger,

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all through the cosmic
history and the, yeah,

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the signal of them combining
adding together is what,

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um, led to this little distortion,

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a little humming in the
signal in the, in the,

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in the deviation of the pulsar
arrival time that we see.

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Why do we think that it is specifically
those mergers over time that's caused

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this hum? What's, what tells us that.

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In fact we are not a hundred
percent sure what we are detecting

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is from super massive black hole.

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It is however the very most likely reason

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because.

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It's sort of so big that it has to be
something that catastrophic if you.

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Well, I think it's smart that, you know,

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from Einstein has predicted when
massive objects come together,

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they will lead to the emission
of gravitational wave.

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So we think super massive black hole
merger will definitely cause this.

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And from simulation we under,

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well we have some idea of how many of
these events might have happened during

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the cosmic time and if we,
if they emit in this way,

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we see that they would add up to such a
kind of signal that Tulsa timing array

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would have detect something
by now. And we did,

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we indeed detect features in our
data that is consistent with this,

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these predictions.

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This is why we think supermarket black
hole merge pre-merger is the best

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explanation. However,

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there are other possible
courses for these background

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gravitational waves that could
lead to this humming that we see

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now data including dark matter axion,

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black holes left from the
beginning of the universe,

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the so-called primo black holes
and even cosmic strains. So

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it's not a, yeah, it's not a, it's not
a done deal yet. We are still, we will,

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we will need to improve the, um,

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sensitivity of the postal timing array
experiment to really pinpoint, um,

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the exact, uh, origin of these signals.

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And I think we will be able to achieve
that in the next years because,

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um, so the, the recent discoveries is
published by diff individual different,

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um, postal timing communities.

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There are a number of collaborations
that have been working on this postal

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timing array experiments.

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So there's a large North American
collaboration called nanogram.

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There is the European Timing Array,

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there is the Australian
Pulsar Timing Array.

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There is a group in India and there's
a group in China and they have all

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sort of seen the same signals now.

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But the next step is really to combine
data from all these individual groups

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that this is what we're called the
International Postal Timing Array,

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and which will have the
most sensitive detection,

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00:15:19,100 --> 00:15:21,320
the best sensitivity of all,

236
00:15:21,500 --> 00:15:24,240
and hopefully we'll be able to
answer some of these questions. So.

237
00:15:24,240 --> 00:15:26,120
Are there particular pulse
cells that you're looking at?

238
00:15:26,150 --> 00:15:27,400
Yeah, personally, uh,

239
00:15:27,540 --> 00:15:31,320
my role in the Pulsar timing array
experiment is that I have, um,

240
00:15:32,470 --> 00:15:36,920
conducted many of the
nanogram pulsar observations

241
00:15:37,170 --> 00:15:41,760
using the R receivable and the
green bank telescope. Um, uh,

242
00:15:41,880 --> 00:15:43,040
a nanogram for example,

243
00:15:43,100 --> 00:15:47,040
we have about 80 millisecond
pulsars that we monitor

244
00:15:47,630 --> 00:15:51,960
regularly. Uh, well our receivable
has been decommissioned, uh,

245
00:15:52,140 --> 00:15:57,040
two years ago, I think now it's
been two years. Um, but uh, with,

246
00:15:57,620 --> 00:15:57,890
uh,

247
00:15:57,890 --> 00:16:02,640
green Bank we get these regular
scheduled time to monitor the pulsar

248
00:16:03,940 --> 00:16:08,680
in the array experiment. I also
use the chime radio telescope,

249
00:16:08,860 --> 00:16:12,840
the, um, one in Canada that
I mentioned earlier. Um,

250
00:16:13,050 --> 00:16:18,000
chime gets to see, um,
the sky every single day.

251
00:16:18,420 --> 00:16:23,200
So we have really high
cadence observations of all of

252
00:16:23,520 --> 00:16:27,000
these 80 pulsar, some of
them every single day,

253
00:16:27,030 --> 00:16:30,200
some of them every few days. So, um,

254
00:16:31,080 --> 00:16:35,840
we analyze all these data and
add them to the pulsar timing

255
00:16:36,290 --> 00:16:37,280
every experiment.

256
00:16:37,780 --> 00:16:42,000
So something quite probably
colliding super massive black holes

257
00:16:42,700 --> 00:16:47,480
is sending out gravitational waves
across space and disturbing the

258
00:16:47,720 --> 00:16:51,000
pulsars and our reading of
them back here on Earth.

259
00:16:51,380 --> 00:16:55,000
But how significant is that? What
can we use that discovery for?

260
00:16:55,130 --> 00:17:00,000
These objects that ate
gravitational waves such as super

261
00:17:00,000 --> 00:17:04,560
massive black hole? It's, they
are, they are invisible to most,

262
00:17:04,820 --> 00:17:09,040
uh, electromagnetic waves
because they do not, um,

263
00:17:09,140 --> 00:17:13,400
we cannot detect them in another
way. So using reputational waves,

264
00:17:13,400 --> 00:17:18,000
it really opens up a new window to
study these sources that we cannot

265
00:17:18,610 --> 00:17:19,680
probe otherwise.

266
00:17:21,100 --> 00:17:26,000
The reason is that gravitate
gravitational waves interacts very weakly

267
00:17:26,150 --> 00:17:30,720
with matter, so they
basically pass through, uh,

268
00:17:31,060 --> 00:17:34,600
the cosmic history untouched.

269
00:17:35,910 --> 00:17:39,490
And so studying the, studying
these gravitational waves,

270
00:17:39,510 --> 00:17:44,250
we can really learn about these objects
that emitted them from the first place.

271
00:17:44,630 --> 00:17:49,170
We are also hoping to get
a better understanding of
these merger of supermassive

272
00:17:49,490 --> 00:17:51,640
hole, of how, um,

273
00:17:51,990 --> 00:17:56,880
they merge together forming the
bigger galaxy and how, um, these

274
00:17:58,490 --> 00:18:03,210
hierarchical merging events lead to
the universe as we know it today.

275
00:18:03,600 --> 00:18:04,433
Okay.

276
00:18:04,490 --> 00:18:06,570
Brilliant. How can we use those pul sars?

277
00:18:06,640 --> 00:18:09,170
They act as almost like a cosmic clock.

278
00:18:10,330 --> 00:18:13,190
We know exactly when the
next pulse is going to come.

279
00:18:14,010 --> 00:18:18,830
And so by studying the arrival
time of these pulses and

280
00:18:18,970 --> 00:18:19,410
to,

281
00:18:19,410 --> 00:18:24,390
and by paying attention to whether there's
any deviations from what we expect,

282
00:18:24,970 --> 00:18:27,430
we can work backward to see, ah,

283
00:18:27,540 --> 00:18:32,420
what might have caused these
distortion in the arrival time or

284
00:18:32,520 --> 00:18:35,900
why are these pulses coming
earlier? And some are the later,

285
00:18:36,170 --> 00:18:39,580
some other ones later. And this
is exactly what we have done.

286
00:18:39,630 --> 00:18:42,940
We've studied many pulsers in
different part of the skies,

287
00:18:42,960 --> 00:18:47,660
and by realizing that some
of these pulses comes earlier

288
00:18:47,800 --> 00:18:49,660
and some of these pulses come later,

289
00:18:50,080 --> 00:18:54,060
we figured out that there must have
been a gravitational waves that has

290
00:18:54,060 --> 00:18:58,660
distorted the space time between
the earth and these pulsars.

291
00:18:58,680 --> 00:19:02,580
That's brilliant. So you were involved
in this fairly early on. Does it,

292
00:19:02,760 --> 00:19:06,420
is it something that you've been
desperately waiting to hear the news?

293
00:19:06,530 --> 00:19:09,340
What does it, what makes you
want to go back to study?

294
00:19:09,490 --> 00:19:13,620
Yeah, pulsar is very, um,

295
00:19:14,040 --> 00:19:16,940
how do I say it's, uh,
very dear to me. It's, um,

296
00:19:16,940 --> 00:19:20,060
what I did my PhD thesis on.

297
00:19:21,950 --> 00:19:26,680
I've, um, um, spent a lot of my
research time studying pulsars.

298
00:19:27,080 --> 00:19:30,320
I was involved in monograph mostly, uh,

299
00:19:30,510 --> 00:19:35,240
between 2015 and 17 where
I collected a lot of these

300
00:19:35,440 --> 00:19:36,920
pulsar observations during the time.

301
00:19:37,260 --> 00:19:41,800
So it was really exciting
to see these decade long

302
00:19:41,800 --> 00:19:46,800
efforts finally coming to fruition
that we could finally say we have seen

303
00:19:47,260 --> 00:19:49,600
the evidence of gravitational waves.

304
00:19:49,600 --> 00:19:54,440
But I think the cool thing is
this is just the beginning. Um,

305
00:19:54,700 --> 00:19:58,720
we know that the next step is to combine
the data set from all these different

306
00:19:58,810 --> 00:20:02,160
experiment and for sure the
sensitivity will increase.

307
00:20:02,650 --> 00:20:06,800
We'll hopefully be able to really
study the astrophysics of these

308
00:20:07,120 --> 00:20:11,440
superman black hole and how the merger
history throughout the universe.

309
00:20:12,130 --> 00:20:13,400
We'll return to cherry shortly,

310
00:20:13,740 --> 00:20:18,480
but this news has caused perturbations
beyond the Pulsar community.

311
00:20:19,360 --> 00:20:24,240
Al Cordova describes herself as a
writer of words, maker of videos,

312
00:20:24,770 --> 00:20:28,960
lover of the cosmos, sci-fi
tv, movies and literature.

313
00:20:29,260 --> 00:20:31,120
And she posted this on Instagram.

314
00:20:31,900 --> 00:20:33,840
We got space time compressions,
gravitational waves,

315
00:20:33,990 --> 00:20:36,040
signals coming from the
Pulser timing array.

316
00:20:36,250 --> 00:20:40,080
We're using spinning stars as a telescope
to watch some old black holes doing do

317
00:20:40,080 --> 00:20:43,480
to dose. Now these waves could be coming
from dozens of things, dark mattered,

318
00:20:43,560 --> 00:20:46,080
worm holes, even cosmic strains
because the universe is old,

319
00:20:46,080 --> 00:20:49,200
it's been busy as hell. So where the
ripples come from is kind of hard to tell,

320
00:20:49,340 --> 00:20:52,280
but the drumming and the drumming of the
waves that are coming is the summing of

321
00:20:52,280 --> 00:20:55,760
a humming that's becoming so stunning
and it really paints a beautiful tapestry

322
00:20:55,860 --> 00:20:58,240
of the ancient cosmos
and its majesty. Look,

323
00:20:58,240 --> 00:21:01,000
we're just a little planet in the Milky
way of burbs trying to understand the

324
00:21:01,200 --> 00:21:04,360
universe and how it occurred and now
we have a brand new way to observe.

325
00:21:04,460 --> 00:21:07,840
So it's just another win for the
whole planet Earth. Well done guys.

326
00:21:13,290 --> 00:21:17,080
Vasel Cordova and the beat is
by Cato producer on Instagram.

327
00:21:17,420 --> 00:21:21,080
My own foray into the world
of physics began by studying

328
00:21:22,230 --> 00:21:26,840
Seti, the search for extraterrestrial
intelligence at Chadro Bank linked to the

329
00:21:26,840 --> 00:21:31,120
Manchester University. So when Cherry
said that she's now working with Seti,

330
00:21:31,480 --> 00:21:36,480
I wanted to know more about what
she's up to since working on the

331
00:21:36,680 --> 00:21:38,200
Pulsar timing array. Yeah.

332
00:21:38,200 --> 00:21:41,480
It was actually very interesting how, uh,

333
00:21:41,800 --> 00:21:44,480
I got involved in Seti. Like I said,

334
00:21:44,480 --> 00:21:49,320
my background is in Pulsar and I worked
on Phos Fast fast radio burst as well.

335
00:21:49,900 --> 00:21:54,800
It turned out that the study of Pulsar
Fast Radio burst and Seti actually have

336
00:21:54,830 --> 00:21:56,760
some common ground. Um,

337
00:21:56,760 --> 00:22:01,520
basically we are detecting very
small signals in the radio, uh, data.

338
00:22:02,180 --> 00:22:03,840
And so I started, uh,

339
00:22:04,150 --> 00:22:08,640
working with the Breakthrough
Listen initiatives in

340
00:22:08,700 --> 00:22:10,320
2021, I think.

341
00:22:10,620 --> 00:22:15,120
And I was leading the
commissioning of two city

342
00:22:15,320 --> 00:22:17,440
projects on one on the,

343
00:22:17,700 --> 00:22:22,240
on the very luxury in the US and
MECA telescope in South Africa.

344
00:22:22,620 --> 00:22:25,400
We are hoping to use this really, um,

345
00:22:26,060 --> 00:22:28,840
state-of-the-art radio telescope to

346
00:22:31,090 --> 00:22:35,590
do a systematic search for
set signal in the sky. Um,

347
00:22:36,080 --> 00:22:40,470
these telescope are
interferometric facilities and

348
00:22:41,060 --> 00:22:45,990
what that means is that they can give
us a really large sky mapping speed so

349
00:22:45,990 --> 00:22:50,310
that we can scan a large part
of the sky, um, all at once.

350
00:22:51,130 --> 00:22:53,870
In my opinion, we
haven't detected any, um,

351
00:22:56,380 --> 00:23:00,410
convincing e t I signals yet, but

352
00:23:02,490 --> 00:23:05,410
I don't think they necessarily not exist.

353
00:23:05,570 --> 00:23:07,690
I think we just haven't looked enough.

354
00:23:08,350 --> 00:23:11,850
If you take a look at the parameter space,

355
00:23:11,950 --> 00:23:15,690
we have searched for steady
signal throughout, um,

356
00:23:17,250 --> 00:23:21,090
the time we haven't, we have
only, um, well we haven't,

357
00:23:21,090 --> 00:23:22,490
we haven't looked much really,

358
00:23:23,110 --> 00:23:27,650
we have only searched for a very small
range of emitting frequency range and the

359
00:23:27,650 --> 00:23:32,570
number of stars that we have observed is
only to the other of a thousand or so.

360
00:23:32,670 --> 00:23:36,930
And this is tiny fraction compared to
the total number of stars even in our

361
00:23:36,980 --> 00:23:39,370
Milky Way galaxy. So, um,

362
00:23:39,890 --> 00:23:44,210
I think with the V L A and the
MECA study project, this will,

363
00:23:44,210 --> 00:23:49,110
they will really bring a game changer
to the set field by hugely increasing

364
00:23:49,170 --> 00:23:53,590
the number of stars we can
monitor for any setty signal.

365
00:23:54,050 --> 00:23:54,270
If.

366
00:23:54,270 --> 00:23:59,270
You did find an extra terrestrial
intelligence and you could

367
00:23:59,550 --> 00:24:03,710
communicate with it, what would you
ask is what would you ask it? You know,

368
00:24:03,710 --> 00:24:07,830
whether these gravitational waves were
caused by super massive black holes

369
00:24:07,900 --> 00:24:09,030
combining, for example.

370
00:24:09,590 --> 00:24:13,870
<Laugh>. I think

371
00:24:15,870 --> 00:24:19,670
I know if I can only ask for one,
if I can only ask one question,

372
00:24:19,870 --> 00:24:24,710
I think it won't be this one because I
think we are quite sure that it should be

373
00:24:24,800 --> 00:24:26,910
super massive like h
causing the gravitational.

374
00:24:27,190 --> 00:24:31,830
I think if I to wanna ask my
question probably be how can humanity

375
00:24:32,020 --> 00:24:33,750
survive climate change <laugh>.

376
00:24:33,970 --> 00:24:36,950
I'd like to thank Jenny Eng for talking
to me for this episode of the Physics

377
00:24:36,950 --> 00:24:41,830
World Stories podcast and I can't help
but wonder whether we will find signs of

378
00:24:41,890 --> 00:24:46,350
extraterrestrial intelligence or a
solution to climate change. First,

379
00:24:47,050 --> 00:24:47,883
in any case,

380
00:24:48,010 --> 00:24:51,990
the next steps for NANOGrav and the other
gravitational wave groups around the

381
00:24:51,990 --> 00:24:56,310
world is to try and sift through the
background to distinguish specific

382
00:24:56,310 --> 00:25:00,870
gravitational waves and trace them
back to their sources and they can then

383
00:25:01,100 --> 00:25:04,550
combine that data with the
observations that have been made in the

384
00:25:04,550 --> 00:25:06,710
electromagnetic areas of light.

385
00:25:07,130 --> 00:25:11,790
And the potential is there for new
and exciting discoveries to be made

386
00:25:12,090 --> 00:25:16,750
in this new frontier for astronomy.
Speaking at that nano GR announcement,

387
00:25:17,410 --> 00:25:19,550
here's Dr. Maura McLaughlin,

388
00:25:19,890 --> 00:25:24,030
the Ely Distinguished Professor of
physics and astronomy at West Virginia

389
00:25:24,120 --> 00:25:24,953
University.

390
00:25:25,220 --> 00:25:28,110
Well this is not at all the
end of the story <laugh>.

391
00:25:28,380 --> 00:25:30,710
This is just the end of the beginning.

392
00:25:32,250 --> 00:25:34,570
Nanogram is already working
on our next dataset,

393
00:25:34,940 --> 00:25:38,810
which we'll have 17 to 18
years of pulsar timing data.

394
00:25:39,910 --> 00:25:43,450
And we expect that the evidence for the
gravitational wave background that we

395
00:25:43,450 --> 00:25:46,690
have found in this dataset to
be much stronger in that one.

396
00:25:48,190 --> 00:25:52,370
And we're going to become even more
sensitive with time as we increase the

397
00:25:52,370 --> 00:25:56,440
length of our dataset as we
add more pulsars to our array,

398
00:25:56,940 --> 00:25:58,040
and most importantly,

399
00:25:58,270 --> 00:26:03,200
gain access to bigger and better new
radio telescopes with more dedicated

400
00:26:03,560 --> 00:26:06,890
nanogram observing time. In addition,

401
00:26:07,670 --> 00:26:12,010
we are very proud to be a member of
the International Pulsar Timing Array.

402
00:26:13,790 --> 00:26:18,770
The I P T A was formed 15 years
ago and consists of Pulsar

403
00:26:18,770 --> 00:26:23,010
timing array collaborations
worldwide today

404
00:26:23,630 --> 00:26:26,970
groups in Europe, Australia, India,

405
00:26:27,590 --> 00:26:32,410
and China have also released results
from their most recent gravitational wave

406
00:26:32,730 --> 00:26:33,563
analysis.

407
00:26:34,170 --> 00:26:38,150
And we all see similar features
in our independent data sets,

408
00:26:38,800 --> 00:26:42,950
which of course is reassuring
and also incredibly exciting.

409
00:26:44,600 --> 00:26:45,320
Furthermore,

410
00:26:45,320 --> 00:26:49,610
through this collaboration and partially
supported through an N S F Excel net

411
00:26:49,610 --> 00:26:50,443
Award,

412
00:26:50,830 --> 00:26:55,210
we are working with colleagues around
the world to combine our current dataset

413
00:26:55,600 --> 00:27:00,370
with Pulsar timing datasets from large
radio telescopes in Europe, India,

414
00:27:00,820 --> 00:27:02,690
South Africa, and Australia,

415
00:27:03,510 --> 00:27:08,050
to form an Uber dataset that will be
much more sensitive than any of the

416
00:27:08,050 --> 00:27:09,850
individual data sets alone.

417
00:27:10,950 --> 00:27:15,690
We aim to announce results
from a gravitational wave
analysis of this combined

418
00:27:15,890 --> 00:27:18,370
I P T A dataset within
the next year or two.

419
00:27:20,360 --> 00:27:23,690
This analysis will be
truly transformative.

420
00:27:24,710 --> 00:27:29,370
It should result in a significant
detection of this gravitational wave.

421
00:27:29,370 --> 00:27:33,610
Background hum. In this
combined I P T A dataset,

422
00:27:34,120 --> 00:27:38,860
we may even detect our first individual
supermassive black hole binary

423
00:27:38,920 --> 00:27:43,920
source and likely also be able to
observe it with electromagnetic

424
00:27:43,930 --> 00:27:48,560
telescopes at optical x-ray
or other wavelengths truly

425
00:27:48,560 --> 00:27:53,160
ringing in the era of multi messenger
ano hertz gravitational wave

426
00:27:53,600 --> 00:27:57,240
astronomy. Ultimately,

427
00:27:57,780 --> 00:28:02,400
we will produce an incredible map
of invisible gravitational waves

428
00:28:02,550 --> 00:28:06,480
from gargantuan black holes
spread across cosmic time.

429
00:28:07,920 --> 00:28:12,780
We will also probe some other exotic and
less well understood sources for this

430
00:28:12,780 --> 00:28:13,613
background.

431
00:28:14,750 --> 00:28:19,410
We are so thrilled that you are
joining us on this journey. Thank you.

432
00:28:20,830 --> 00:28:25,130
At one time, all we knew about the
universe resulted from visible light,

433
00:28:25,130 --> 00:28:26,370
light we can see with our eyes.

434
00:28:27,120 --> 00:28:30,930
Then when radio and x-ray and
gamma ray telescopes came online,

435
00:28:31,470 --> 00:28:34,570
we learned so much about the universe
that we just couldn't have imagined

436
00:28:34,750 --> 00:28:38,570
before, like the radio pulsars that
Jocelyn discovered over 50 years ago.

437
00:28:39,960 --> 00:28:44,660
Now we can only dream about what we'll
learn with observations and a different

438
00:28:44,690 --> 00:28:48,620
part of the gravitational wave
spectrum from the LIGO detections that

439
00:28:48,620 --> 00:28:53,500
visionaries like KIPP made possible with
continued investment in our science,

440
00:28:53,650 --> 00:28:55,580
science and in large radio telescopes.

441
00:28:56,360 --> 00:28:59,180
And we are certainly
expecting the unexpected.

442
00:29:00,000 --> 00:29:02,520
All we have to do is keep listening.

443
00:29:07,650 --> 00:29:12,080
We'll be back in September when
we'll be looking at Green energy,

444
00:29:12,710 --> 00:29:16,640
including an intriguing new project
from the European Space Agency called

445
00:29:16,870 --> 00:29:18,880
Solaris. I dunno about you,

446
00:29:19,060 --> 00:29:21,920
but that makes me want to watch an
old Russian science fiction film.

447
00:29:22,300 --> 00:29:27,120
But this is about solar
panels in space feeding

448
00:29:27,190 --> 00:29:31,480
back their energy to earth. And if
that sounds like science fiction,

449
00:29:31,900 --> 00:29:36,480
that's because it is. I can recommend
News from Gardenia by Robert Lou Ellen,

450
00:29:36,980 --> 00:29:40,280
who you might remember as
Creighton from Red Dwarf.

451
00:29:41,210 --> 00:29:44,190
His science fiction novel
contains that very idea.

452
00:29:44,650 --> 00:29:47,830
And if you are looking for some reading
this August ahead of that podcast,

453
00:29:48,140 --> 00:29:52,510
next September News from the Squares
and the book that comes before it,

454
00:29:52,780 --> 00:29:55,710
news from Gardenia, from
Robert Lu Ellen. Good.

455
00:29:55,710 --> 00:29:58,270
Make a welcome edition
to your summer reading.

456
00:29:58,760 --> 00:30:03,150
We'll be back with more on Solaris and
some other fascinating projects next

457
00:30:03,150 --> 00:30:06,710
month. But for now, thank
you very much for listening.

458
00:30:11,340 --> 00:30:13,350
Physics world. I.