
ESO Telescopes Observe First Light from Gravitational Wave Source - acqq
https://www.eso.org/public/news/eso1733/
======
WD-42
If any of you are interested in some of the software that made this discovery
possible, check out two of the papers from Las Cumbres Observatory:

[http://www.nature.com/nature/journal/vaop/ncurrent/full/natu...](http://www.nature.com/nature/journal/vaop/ncurrent/full/nature24291.html?foxtrotcallback=true)

[http://iopscience.iop.org/article/10.3847/2041-8213/aa910f/m...](http://iopscience.iop.org/article/10.3847/2041-8213/aa910f/meta;jsessionid=24CB64879B5A141DC8F45A67DC33EAA0.c2.iopscience.cld.iop.org#apjlaa910fs2)

We run a network of 20 telescopes that are triggered remotely (mostly via
API). Because of our ability to schedule observations quickly, we were the
only ones able to observe the peak luminosity of the kilonova.

Disclosure: I am a software engineer at LCO.

~~~
mads
How did you get this job?

I studied astrophysics, but I mainly try to lure people into clicking on ads
these days, when I am not doing consulting.

~~~
WD-42
Random internet browsing! I have a previous interest in astronomy and I
stumbled upon our website, which had a jobs page. They were looking for
someone with Django experience.

The field has an increasingly large demand for people with software
engineering experience due to the complexity of modern observatories,
instrumentation and data analysis. It's only going to grow from here. The
problem is competing with SV, which tends to be a black hole for talented
software engineers.

~~~
thecrazyone
Just curious, do you mean that SV's a dead end for talented software
engineers? or just that it tracts most of them?

~~~
kamaal
I think the meaning implied is in terms of quality of work. Even the best
Silicon Valley company you might join, the big ones that pay well, will
largely have you parsing xmls or other mundane programming ritual done and
demonstrated to death.

Controlling telescopes, photographing once in a billion year astronomical
events obviously has its coolness factor associated with it.

------
knice
A team from UC Santa Cruz used the data from the Swope telescope in Chile to
locate the source of the gravitation waves and observe the light from the
event. The data provides evidence of how gold and other heavy elements formed
in the universe.

[http://reports.news.ucsc.edu/neutron-star-
merger/](http://reports.news.ucsc.edu/neutron-star-merger/)

[https://www.youtube.com/watch?v=R5EkI5qbYYc](https://www.youtube.com/watch?v=R5EkI5qbYYc)

Full disclosure: I work at UC Santa Cruz and built the site linked above. :-)

~~~
espadrine
Congrats!

How do you automate screening the sky?

Do you have robots that map stars, diff the images, and send an email when the
diff has a new spot of light?

How frequently does the sky get fully screened? Could there be events fast
enough that we don't detect them?

~~~
knice
Apologies, I'm not one of the researchers involved in the discovery. I'm just
the web developer who built the announcement site for UCSC. Ryan Foley will
participate in a Reddit AMA tomorrow (Tuesday, 10/17). I imagine your
questions might get answered there.

------
hliyan
To put this in perspective:

Since the first hominids looked up at the stars, till literally yesterday,
mankind had only one fundamental force to observe the universe with:
electromagnetic waves, be it light, radio waves or infrared. From today, we
have two. The other two remaining fundamental forces do not operate at
astronomical scales.

Of course, we had LIGO before yesterday, but for me, the confirmation through
electromagnetic wave observations is key. This is an historic day!

~~~
semaphoreP
We've also been observing the universe using neutrinos (generated by the weak
force). In fact, there have even been one neutrino event linked to a possible
astrophysical source[1], but with less certainty than this gravitational
wave/EM detection.

[1]: [https://www.nasa.gov/feature/goddard/2016/nasas-fermi-
telesc...](https://www.nasa.gov/feature/goddard/2016/nasas-fermi-telescope-
helps-link-cosmic-neutrino-to-blazar-blast/)

~~~
pvg
Supernovae neutrinos have been detected for 30 years, it's not just one event.

------
epberry
This is so cool because we used our ears (the LIGO detectors) to hear/feel the
gravitational wave hit then used our eyes (electromagnetic radiation
telescopes) to focus in on where we thought we felt the ripple. And what's
more, machines all over the planet were involved. Just awe-inspiring.

~~~
zyngaro
Wonderfully summed up. Thank you. By the way I thought gravitational waves
have only been a theory. How can they be detected and is there such a thing as
a gravitational quantum ?

~~~
jasonwatkinspdx
Gravitational wave detectors like LIGO
([https://www.ligo.caltech.edu/page/what-is-
ligo](https://www.ligo.caltech.edu/page/what-is-ligo)) are very precise laser
range finders used as rulers. They can measure extremely small expansions and
contractions of space itself.

Discovering a quantized theory of gravity is possibly _the_ major open
question in physics atm. We presume there's a 'graviton' of some sort, but
have not observed it yet.

~~~
peeters
If I'm remembering the analogy in the livestream correctly, if you applied the
laser's precision to astronomical scales, it would be the equivalent of
measuring the distance to the moon with a tolerance the width of a human hair.
And in the scales they deal with, a tolerance one-tenth the diameter of a
proton.

------
zymhan
The Gravitational wave was detected 2 seconds before the Gamma Ray Burst. I
wonder why it is faster?

> On 17 August 2017 the NSF's Laser Interferometer Gravitational-Wave
> Observatory (LIGO) in the United States, working with the Virgo
> Interferometer in Italy, detected gravitational waves passing the Earth.
> This event, the fifth ever detected, was named GW170817. About two seconds
> later, two space observatories, NASA’s Fermi Gamma-ray Space Telescope and
> ESA’s INTErnational Gamma Ray Astrophysics Laboratory (INTEGRAL), detected a
> short gamma-ray burst from the same area of the sky.

~~~
davidhyde
The gravitational waves here were measured for about 100 seconds (as opposed
to the much shorter 'chirp' from the first gravitational wave detection made
in 2016) so the whole event took some time to unfold.

The 2 second delay was due to the fact that gamma rays were generated by
matter slowing down after it was ejected from the system and which collided
with galactic gas. That matter was ejected from the black hole's axis of
rotation and the black hole formed some time after the gravity waves were
detected.

Take a look at this article:
[http://physicsworld.com/cws/article/news/2017/oct/16/spectac...](http://physicsworld.com/cws/article/news/2017/oct/16/spectacular-
collision-of-two-neutron-stars-observed-for-first-time)

"As this material was sucked into the black hole, a fast-moving jet of
material blasted outward along the black hole's axis of rotation. When this
jet collided with gas in the galaxy, it started slowing down and the lost
kinetic energy was broadcast as gamma rays"

~~~
rocqua
Is that essentially cherenkov radiation? That does seem to require charged
particles, so it seems unlikely.

If not, is it black body radiation due to the heat, or just excess energy from
nuclear reactions that are caused by the high-speed neutrons.

~~~
raverbashing
It seems to me it's Bremsstrahlung turned to 11 -
[https://en.wikipedia.org/wiki/Bremsstrahlung](https://en.wikipedia.org/wiki/Bremsstrahlung)

------
azizsaya
NPR article does a good job of simplifying this, I hope it is technically
correct!

[http://thin.npr.org/s.php?sId=557557544](http://thin.npr.org/s.php?sId=557557544)

------
apetresc
It appears this was the discovery, they're talking about it on stream now:
[http://www.eso.org/public/news/eso1733/](http://www.eso.org/public/news/eso1733/)
(ESO Telescopes Observe First Light from Gravitational Wave Source)

The stream is at: [http://www.eso.org/public/](http://www.eso.org/public/)
It's currently being explained right now.

~~~
1001101
Taking a while to load. The summary suggests that GRBs are caused by neutron
star mergers:

"ESO’s fleet of telescopes in Chile have detected the first visible
counterpart to a gravitational wave source. These historic observations
suggest that this unique object is the result of the merger of two neutron
stars. The cataclysmic aftermaths of this kind of merger — long-predicted
events called kilonovae — disperse heavy elements such as gold and platinum
throughout the Universe. This discovery, published in several papers in the
journal Nature and elsewhere, also provides the strongest evidence yet that
short-duration gamma-ray bursts are caused by mergers of neutron stars."

------
cromwellian
Veritasium summary is one of the best easily digestable I've seen.

[https://www.youtube.com/watch?v=EAyk2OsKvtU](https://www.youtube.com/watch?v=EAyk2OsKvtU)

~~~
acqq
I like much more this one by the Science Magazine:

[https://www.youtube.com/watch?v=e_uIOKfv710](https://www.youtube.com/watch?v=e_uIOKfv710)

and this one by The Georgia Institute of Technology:

[https://www.youtube.com/watch?v=pLivjAoDrTg](https://www.youtube.com/watch?v=pLivjAoDrTg)

~~~
spuz
I disagree, the Veritasium video has way more information than the two videos
you linked. It shows how the gamma ray telescopes and gravitational wave
detectors worked together to narrow the source in the sky of event. What a
gravitational wave signal looks like, what a gamma ray signal looks like. The
fact that the optical signal was made 11 hours after that. Etc. There is a lot
more info on top of that which makes the video worth watching.

~~~
cromwellian
Yes, the fact that the negative detection by Virgo was actually significant
was interesting.

------
bd
Here is LIGO live stream:

[https://www.youtube.com/user/VideosatNSF/live](https://www.youtube.com/user/VideosatNSF/live)

This was LIGO (US) + Virgo (EU) + 70 ground- and space-based observatories
collaboration:

[http://www.ligo.org/](http://www.ligo.org/)

[http://www.virgo-gw.eu/](http://www.virgo-gw.eu/)

------
smortaz
Relevant: if you want run their actual code via your browser, check out their
jupyter notebooks:

[https://notebooks.azure.com/roywilliams/libraries/LIGOOpenSc...](https://notebooks.azure.com/roywilliams/libraries/LIGOOpenScienceCenter)

Click View to read or Clone to make your own copy and run.

------
occultist_throw
BTW, this is also the basis of a story by Greg Egan. Diaspora. (Aside: I
highly recommend Greg Egan's work, especially Diaspora)

The claim he makes in the fiction novel, is that a neutron star-neutron star
collision event would be enough energy to sterilize 100 light year radius
around the event. The one in the novel happens closer than 100ly.

[http://www.gregegan.net/DIASPORA/DIASPORA.html](http://www.gregegan.net/DIASPORA/DIASPORA.html)

------
gigatexal
As a fan of the Astro-sciences I am so glad to be alive. I have all the
confidence that within my lifetime hopefully (next 50 years hopefully) we will
see great things maybe even a unification relativity and quantum mechanics.

------
Gravityloss
Can some astronomer or physicist actually make an image where the source is
marked? All I see is some stars and a galaxy which is basically and some
textual explanation where I should look for it.

~~~
WD-42
Here is a nice image
[https://lco.global/files/blog/lco_skymap_logo.jpg](https://lco.global/files/blog/lco_skymap_logo.jpg)

------
acqq
The main paper about the detections:

[http://iopscience.iop.org/article/10.3847/2041-8213/aa91c9](http://iopscience.iop.org/article/10.3847/2041-8213/aa91c9)

"Multi-messenger Observations of a Binary Neutron Star Merger"

published in The Astrophysical Journal Letters.

PDF:

[http://iopscience.iop.org/article/10.3847/2041-8213/aa91c9/p...](http://iopscience.iop.org/article/10.3847/2041-8213/aa91c9/pdf)

ePub:

[http://iopscience.iop.org/article/10.3847/2041-8213/aa91c9/e...](http://iopscience.iop.org/article/10.3847/2041-8213/aa91c9/epub)

"Some researchers say it has 4600 authors," I haven't counted myself.

------
quickthrower2
Was about to submit [https://qz.com/1102917/observing-the-merger-of-neutron-
stars...](https://qz.com/1102917/observing-the-merger-of-neutron-stars-
finally-explains-where-in-the-universe-heavy-elements-are-made/)

------
czardoz
This seems to be the press release:
[https://www.eso.org/public/news/eso1733/](https://www.eso.org/public/news/eso1733/)

Edit: The main link points here as well now.

~~~
acqq
This link here always pointed to the link you have given, you probably
confused this post and another on the first page:

[https://news.ycombinator.com/item?id=15483186](https://news.ycombinator.com/item?id=15483186)

That one is only an announcement of the press event, posted cca 7 minutes
before the start of the event, not what was discovered, which was officially
published exactly at the start of the hour, as the news conferences started.

Anyway, at the moment there are still live streams, like

[https://www.youtube.com/watch?v=mtLPKYl4AHs](https://www.youtube.com/watch?v=mtLPKYl4AHs)

10:00 am EDT - Press Conference (Part 1)

11:00 am EDT - YouTube Q&A (ask us in the chat, we will answer on camera)

11:15 am EDT - Press Conference (Part 2)

12:30 am EDT - YouTube Q&A (Part 2)

Also, in Europe (the European Southern Observatory), (edit: finished, now you
can watch the recorded conference at the same link)

[https://www.youtube.com/watch?v=9ISr4juIkDg](https://www.youtube.com/watch?v=9ISr4juIkDg)
)

There's a nice 1 minute animation:

[https://www.youtube.com/watch?v=nziW8fywwmg](https://www.youtube.com/watch?v=nziW8fywwmg)

There's also Reddit "AskScience AMA Series: European Southern Observatory
announcement concerning groundbreaking observations" unlocked now, starting at
18:30 CEST / 12:30 ET:

[https://www.reddit.com/r/askscience/comments/76ne3p/askscien...](https://www.reddit.com/r/askscience/comments/76ne3p/askscience_ama_series_european_southern/)

------
runeb
After observers found the source of the collision the scientist at the Chile
observatory claims to have spent 45 minutes to locate it in the sky. Do they
not have some sort of coordinate system they could use to pinpoint it?

~~~
scentoni
The resolution of our present gravitational wave observations is very low.
Adding VIRGO to LIGO helps reduce the area of the sky to look in.

------
platz
So, was there a telescope monitoring the light location already, or was the
light only found after the Gr detection... I.e. Was it not truly concurrent?

~~~
nerfhammer
they swung the telescopes around to look for it shortly after the detection
event

------
martyvis
Is it just me, or does anyone else think that its strange that an observatory
press release on the specific subject of the "observed light" can only lead it
with what I assume is an artists'impression? I'm sure that there is oodles of
data to go through, but after 3 months, surely a representation of the actual
data imaged could be presented?

~~~
acqq
The actual images are also on the very same page where you only see an artist
impression: PR Image eso1733b, PR Image eso1733c, PR Image eso1733d, PR Image
eso1733e, PR Image eso1733h, PR Image eso1733k, PR Image eso1733m.

There also are actual pictures in the scientific papers, for example:

[http://www.nature.com/nature/journal/vaop/ncurrent/fig_tab/n...](http://www.nature.com/nature/journal/vaop/ncurrent/fig_tab/nature24291_F2.html)

Also see the actual main paper, written by 4600 scientists together: there
were many more observations and images than these two, but unfortunately they
aren't "sexy" for the general public: a dot which appears and then disappears
later. But the astronomers know how to even detect the presence of gold in
that dot! Note: the chemical element helium, which today is even used to fill
the balloons for the children, was first discovered on the Sun(!), using that
kind of observations and analysis, and only later at our Earth.

There is also a video, directly linked from the page you criticize, and part
of the press release, which was made from the real images taken at different
times, where the changes in time are visible:

[https://www.eso.org/public/videos/eso1733c/](https://www.eso.org/public/videos/eso1733c/)

Also, there are a lot of papers that are published, most observers will
publish or have published their observations.

The galaxy where the kilonova happened is some 130 million light years away,
or 8 billion times more distant than the Sun is away from us, and what's
observed (in different spectrums) is a source of a lot of light (or
electromagnetic radiation) at the edge of that galaxy, and also the
gravitational waves. To compare the sizes, there could be 1000 of our own
galaxies placed one after another to fill the distance to that kilonova. There
are around 400 billion stars just in our own galaxy.

------
sandworm101
Cool, but i want more. All we have so far is confirmations of rather well-
understood interactions. I want "we see these massive waves, but have no idea
what is causing them." If they are being seen, such results aren't published.

~~~
dspillett
_> All we have so far is confirmations of rather well-understood
interactions._

Confirmations of _commonly assumed_ interactions. This is vital, as numbers of
other hypothesise/theories/other rely on that understanding. Without results
like these all that work is on shaky ground, now it looks far more solid.

Confirming current understanding isn't as sexy as discovering new physics, but
just as important, possibly more so.

~~~
sandworm101
That depends. I'd bet money that LIGO was not pitched on the idea that it
would only confirm the existence of waves. New instruments are pitched on the
expectation of novel measurements. the "new physics". The parallels to the LHC
and other massively-expensive instruments are striking. They confirm something
that has already been widely accepted, generate the expected prize and raft of
phds, but when it is all over the universe hasn't changed. I worry that those
greenlighting these projects are being too conservative, only investing in
projects that have clear pathways. This trend matters. Physics needs these
giant instruments to generate something truly new otherwise the billions will
drift towards other disciplines.

~~~
acqq
You are wrong. The LHC was absolutely prepared to observe new "unexpected"
(for the "Standard model") particles. It just didn't happen. A lot of
theorists who had developed the theoretical extensions of the "Standard model"
are disappointed about that, but that's what is observed.

Regarding the gravitational waves, you're also wrong, as the theory and the
observations matched even without the gravitational waves being directly
observed, the science is simply so good that completely unexpected results (in
the sense you talk) are outside of the resulting limits of the previous
measurements and calculations.

The level of the science we have now is really stunning. The only sad part of
the story is that all investments in the science are really minute compared to
all the money spent on armies and weapons (e.g. just as the order of magnitude
one year of the US military budget is at least 30 times bigger than the
NASA's).

There's immense amount of the new information that can be obtained by the
repeated observations. But the expectation of anything to disprove too much of
what we know up to now is simply not realistic.

~~~
sandworm101
LIGO is a new telescope. Everyone is hoping that, like every other form of
telescope ever built, it will 'see' things that we didn't know were out there.
There are lists of unexplained phenomena that telescopes see very regularly.
Trying to explain such observations is the forefront of astronomy and physics
(see dark matter/energy). But this telescope has yet to add to the lists.

[https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_p...](https://en.wikipedia.org/wiki/List_of_unsolved_problems_in_physics#Astronomy_and_astrophysics)

~~~
acqq
This is a huge observation, and many more insights are to come, and that this
one or the previous three didn't add to that list you'd wish to be added to
doesn't in any way diminish the achievement.

------
zitterbewegung
This is awesome! We should be able to find more gravitational wave sources and
it will give us a better picture of the cosmos. Also, that we have more
sources with better correlation and more information.

~~~
cryptonector
The best part is that gravitational waves stand out in a way that events in
the visible spectrum do not, so these gravitational wave observatories will be
helping find events and get them observed in every portion of the
electromagnetic spectrum that we can observe. That means we'll be observing
many more of these kilonovae now. This truly is a new era, as we'll now be
able to use all these observatories at the same time to observe the same
events, and this will yield the highest possible resolution imaging of these
events, as far-flung telescopes are able to function as one really, really
big, virtual one.

~~~
mark-r
How often are these kilonovae expected to occur?

------
CaiGengYang
Why is this post given so many points (521) ? Anyone can explain? Isn't it
simply a post of something someone saw on the internet ?

------
seomint
Non-scientist here, is this a Nobel Prize caliber discovery? Just trying to
get some perspective here. It sounds exciting.

~~~
scentoni
Basically they've made the first direct observations of what causes a
[https://en.wikipedia.org/wiki/Gamma-
ray_burst](https://en.wikipedia.org/wiki/Gamma-ray_burst)

I expect there will be a Nobel, not immediately but after years of
accumulating statistics on many different GRBs.

------
netcraft
awesome discovery. Can't wait to see the pictures. So much closer than the
other detections of black holes - I assume the detection range of neutron
starts is much smaller.

~~~
guelo
Yes. It mentions that in note 4 here
[https://www.eso.org/public/news/eso1733/](https://www.eso.org/public/news/eso1733/)

------
SideburnsOfDoom
And do the gravitational waves propagate at the speed of light?

~~~
fpoling
For 130 million light years the difference between gravitational wave signal
and gamma burst is 2s. That constrains the speed difference to 1.6e-18 m/s.
This is fascinating number especially given that speed of light is 3e8.

~~~
alok-g
Newbie question: While this is a very small fractional difference, could it be
theoretically significant? What is the explanation of this difference? My best
guess is that this difference must also be there in when the waves _started_.

~~~
SideburnsOfDoom
I'm not a physicist, but I did do the 101 course a long time ago. I read "That
constrains the speed difference to 1.6e-18 m/s" as "we measured as accurately
as we could, and if they _do_ differ, they must differ by this amount or less,
which could just be the tolerances of our experiment"

In other words, there's always a confidence interval, the trick is to measure
it and minimise it: The speeds could be identical numbers, but what was
measured was an either no or a very small difference. Larger differences have
been ruled out. Identical numbers are _suggested_.

~~~
alok-g
What is observed is the delay between the two signals. Fractional speed
difference is calculated from it. As I understand, there is little chance that
the 2 second delta isn't real.

~~~
SideburnsOfDoom
OK, but there are other possible explanations besides fundamental physics:
either the order of events at the source, or the effects of the interstellar
medium along the way.

------
johnvega
This stuff makes Elon Musk's plan to colonize Mars relatively less exciting.

------
Boothroid
Am I the only one that's a bit men about this given the pre-conference
hyperbole? I was expecting aliens :(

