
The Absurdity of Detecting Gravitational Waves (2017) [video] - basicplus2
https://www.youtube.com/watch?v=iphcyNWFD10
======
sillysaurus3
Happy to see Veritasium getting some attention on HN. You may have seen his
previous video from 2014, Facebook Fraud:
[https://www.youtube.com/watch?v=oVfHeWTKjag](https://www.youtube.com/watch?v=oVfHeWTKjag)

One of my favorite videos is on his alternate channel, 2veritasum. Survivor
Bias:
[https://www.youtube.com/watch?v=_Qd3erAPI9w](https://www.youtube.com/watch?v=_Qd3erAPI9w)

~~~
RachelF
He's a great presenter, not the normal dumbed down documentaries that are
fashionable these days. He actually tries to explain things, not just waffle
and make the watcher feel good.

He recently made a full length movie:

[https://www.vitamaniathemovie.com/](https://www.vitamaniathemovie.com/)

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acranox
I got to visit LIGO in Louisiana a few years back. I remember they lamented
that it was not as remote as they really wanted. The detector picked up nearby
hunting activity, and logging activity in the woods. And they had to shut down
measurements for a couple hours every week when the liquid nitrogen truck
drove in due to the road vibrations it created.

It’s an awesome experiment. And it requires huge computational resources to
process all the data they take in.

~~~
pinko
The seismic isolation is much better since the Advanced LIGO upgrade completed
in 2014 -- when were you there? (I'm also happy to answer any computing
questions; that's my area.)

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TomMckenny
I wonder if gravity wave detection could be ever be precise enough for
communication.

I wonder this because it occurs to me that one possible answer to Fermi's
paradox is that aliens don't use Radio or other EM to chat.

And maybe they don't leak it because they move energy and information around
more efficiently than we do.

~~~
sillysaurus3
Another answer to the Fermi paradox is that a Kardashev Type 4 civilization is
able to harness the power of an entire universe. We wouldn't be able to detect
this by definition, since they exist outside of our perceived reality.

At first glance, this seems to be a useless theory, since it's not refutable.
But it lends itself to a belief system: by studying the universe, we gain an
understanding of whatever created it. This is helpful as a _motive_ : a reason
for studying any of this at all, in absence of economic or social incentives.

This seems important. As the centuries tick by, and as we confirm and re-
confirm that we are indeed alone and that we do indeed have a mostly-complete
model of physics, there will become less and less incentive to analyze the
corner cases. It's costly, and takes decades. But at one time, it was costly
and took decades to build a cathedral. Yet we accomplished these impressive
feats due to a shared belief system.

The reason I brought this up is that we often like to believe there is an
advanced alien civilization tucked away in some corner of some galaxy, sending
out messages via gravitational waves or neutrinos. But why do humans find this
idea so seductive? It's because of an underlying loneliness: we want to
believe that we are connected with the universe in some fashion, that our
existence has a point, and that there is reason to do anything at all in a
universe that will exist long after we've gone, long after our solar system
and sun has gone. Because if there were an alien civilization, at least we
would not be so alone.

In that context, a solution to Fermi's paradox is simply to believe that our
very universe exists due to some higher-order phenomena not knowable within
our reality. And by studying the laws of physics, we gain a glimpse into the
boundary between our universe and its hypervisor.

~~~
ci5er
> But why do humans find this idea so seductive? It's because of an underlying
> loneliness: we want to believe that we are connected with the universe in
> some fashion, that our existence has a point [...]

No. It's simply that statistically, we can't believe we are the first, nor
that we are unique. It would be (statistically) extremely odd if we were, and
there is a bias against anthropo-centric theories.

Heck, I'd be happier if we are alone (less risk and more free land), but if we
appear to be, that seems odd, and worthy of investigation. No?

EDIT: Why do you claim to speak for all our hopes/dreams/desires? "We need
this" or "We want that". Frankly, that's a little collectivist and creepy.

~~~
spuz
> No. It's simply that statistically, we can't believe we are the first, nor
> that we are unique. It would be (statistically) extremely odd if we were,
> and there is a bias against anthropo-centric theories.

Fermi's paradox does not ask about civilisations like ours. It asks about
interstellar travelling or at least interstellar communicating species. We
have not achieved this level yet so we are not the 'first' as you say. You
might claim that our radio signals should be able to be detected, but they are
so weak and have been travelling for such a short period of time that they may
as well not exist to an outside observer. There may be millions of our type of
civilisation out there presently and throughout history but they would all be
undetectable to us and hence our civilisation doesn't play into the paradox.

~~~
akvadrako
Well one answer to the Fermi paradox is we get wiped out but barring that it
seems unlikely we won't reach the stars in millions of years.

And you seem to ignore it, but the other part of the paradox is if we can
achieve interstellar travel in millions of years, that's like no time at all
on a galactic scale. So it would be a major coincidence if we are within 1
million years of the first.

~~~
spuz
As far as the Fermi paradox is concerned it's a much safer assumption to make
that advanced civilisations will achieve interstellar communication before
they achieve interstellar travel.

Even so, my point is that human technology tells us nothing about the
probility of a civilisation ever developing interstellar communication because
we haven't seen it happen yet. We are still at the 0 stage when going from 0
to 1. It doesn't make sense to extrapolate from our position on the
technological timeline. It makes more sense to assume tabula rasa that aliens
have developed this technology and then explore the implications of that.

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mysterypie
I figured that one tube is stretched by the gravitational waves and the
perpendicular tube is unaffected, so you're measuring the difference between
the two tubes. Simple and easy to understand. However, the video mentioned
that both light and the detection apparatus are stretched by the same degree
and the physicist says "the light does get stretched and that part _doesn 't_
do the measurement for us"[1] -- which makes me think that the simple and easy
explanation is not quite right. There's some subtlety that I think I'm
missing.

[1]
[https://m.youtube.com/watch?v=iphcyNWFD10&t=376s](https://m.youtube.com/watch?v=iphcyNWFD10&t=376s)
(6min 16sec into the video)

~~~
AnsisMalins
Light takes different amounts of time to travel down the stretched vs squeezed
tube.

~~~
stultifying
Yes, the speed of light cannot exceed its limitation, and as one channel
stretches in length, it simply requires more time to travel that length at the
constant maximum speed.

The fixed channel remains the same, and covers the unstretched distance, so
the light, traveling at the same constant speed reaches the end of the
unchanged channel within less time than the other channel.

Or invert the same effect for cases where one channel is compressed to a
shorter length, since waves oscillate. So both circumstances may be
encountered. Some photons will traverse a compressed distance at a fixed
speed, other photons will traverse a stretched distance. Meanwhile, the other
perpedicular path is neither stretched nor squashed, and the photons in that
channel demostrate the difference when compared to the effected channel.

So no matter what happens, the rate of travel is locked at the upper limit of
186,000 miles per second, whether all of space, energy and matter is squashed
in a slightly smaller volume, or expanded to fill a slightly larger volume,
the relativistic distances do not change, and the rate of passage of time does
not change.

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ArtWomb
No concrete data on actual funding increases, but it appears the success of
LIGO and gravity wave detection has kicked off a renaissance in basic research
into fundamental theories of gravitation itself. With a space-based gravity
wave detector in various stages of development. And the possibility that
gravitons have been indirectly observed already.

Is Gravity Quantum?

[https://www.scientificamerican.com/article/is-gravity-
quantu...](https://www.scientificamerican.com/article/is-gravity-quantum/)

~~~
v_lisivka
LIGO is scaled up version of Michelson-Morley experiment, so we should ask
very different kind of question.

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bajsejohannes
One thing the book Black Hole Blues (Janna Levin) brought home to me was the
absurdity of actually getting this project done. Now that it's complete, it's
easy to say that it was obviously a good idea. It's another thing entirely to
bet huge budgets on something that doesn't seem very likely to succeed.

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phkahler
This seems like a thing to build on the moon.

~~~
_Microft
Or even better - make it space based:
[https://en.wikipedia.org/wiki/Laser_Interferometer_Space_Ant...](https://en.wikipedia.org/wiki/Laser_Interferometer_Space_Antenna)

~~~
imnobody
Unfortunate to see NASA was forced to withdrawal (for budgetary concerns).

~~~
sleavey
LISA has now been funded by ESA with a small contribution from NASA. It is
slated for launch in the late 2020s / early 2030s.

