The h Bar

tpg2114

3:02 PM

Youtube (and Twitch) chat should just not exist

Nothing productive has ever been said in either

CR Drost

Awesome, @ACuriousMind .

ACuriousMind

@tpg2114 How could Twitch play things without chat? :O

But you're right, my first click was to minimize the youtube chat

tpg2114

The old AOL chatrooms of the '90s were more civilized.

Here's another stream from the NSF: youtube.com/watch?v=c7293kAiPZw

Not sure if one will be better/worse than the other

user116211

> Stand by

guest

24 minutes

Slereah

3:12 PM

I wish I was a famous scientist

So that I could answer "IT WAS ME" on the history of science SE

Secret

Final 1 minute

countdown

Emilio Pisanty

Another link

youtube.com/user/VideosatNSF/live

Balarka Sen

The hell is a LIGO.

user116211

@BalarkaSen Huh??

Jiminion

Do gravity waves say anything about the discreteness/continuousness of spacetime?

Slereah

3:20 PM

No.

Gravitational waves are purely classical

Balarka Sen

@user36790 That's a vague question, so don't expect answers. :)

Jiminion

LIGO was the bad guy in 'Thunderball'

user116211

@BalarkaSen Neither did I expect answers ;P

guest

Was that a 70s movie :P @Jiminion?

Jiminion

LIGO is the sensor system that detected the waves. There are 2 (?) of them.

60's James Bond film.

Balarka Sen

3:22 PM

What's a wave?

Jiminion

Gravity Wave

user116211

@BalarkaSen WTF!

Emilio Pisanty

That side chat is ridiculous

> no sound

> Press Alt+F4 for audio

guest

Something that "waves"

John Rennie

@Jiminion Gravitational wave not gravity wave!

Balarka Sen

3:23 PM

What's a gravitational wave?

John Rennie

We detected gravity waves a long time ago :-)

The Dark Side

:)

user116211

Gravitational wave

In physics, gravitational waves are ripples in the curvature of spacetime which propagate as waves, travelling outward from the source. Predicted in 1916 by Albert Einstein on the basis of his theory of general relativity, gravitational waves theoretically transport energy as gravitational radiation. The existence of gravitational waves is a possible consequence of the Lorentz invariance of general relativity since it brings the concept of a limiting speed of propagation of the physical interactions with it. By contrast, gravitational waves cannot exist in the Newtonian theory of gravitation, which...

John Rennie

Why is there no sound on the stream? Whaaaaaaaaaa!!!!!!

Emilio Pisanty

@JohnRennie Ctrl+W for audio =P

Isaac Moses

3:25 PM

@JohnRennie To hear the sound, you need to set up two special microphones at right angles to each other

mle

Virgo - Cascina (Pisa - Italy): content.jwplatform.com/players/JK3Q6HUT-uRmjM0Xa.html

John Rennie

On a side note, is Crothers just being a twat here?

@John Rennie - Thanks for your comment. However, your comment makes it very clear that you are not familiar with Kirchhoff's Law of Thermal Emission (not uncommon). To know Kirchhoff's Law implies knowledge of its setting, which is not the setting you have adduced. This is a problem. Can anybody on this site state the correct setting of Kirchhoff's Law of Thermal Emission? — Stephen J. Crothers 5 mins ago

Balarka Sen

I read the first two lines in the wikipedia article, and it didn't make sense. I'm only vaguely aware that spacetime is a Riemannian manifold and that gravity induces curvature. But I haven't heard of this wavy business in all my life.

guest

This is THE EVIDENCE for Einstein :D @Slereah

2

Slereah

Isn't Crothers always a twat

user116211

3:29 PM

@JohnRennie: Did sound come?

John Rennie

We got sound :-)

guest

@mle your link works!!!

They detected the waves.

2

user116211

HISTORY!!

Balarka Sen

Oh, so these wavy fellows come from two masses orbiting around each other. Fair enough.

promptly goes back to eating popcorn and thinking about homologous cochains

leongz

who's the lady speaking?

John Rennie

3:33 PM

Head of the NSF

Secret

tpg2114

"So uhhh.... we broke LIGO and we need more money... Don't know why this got so blown out of proportion and we needed to have this whole thing..."

user116211

Buffering ;(

leongz

lol

guest

SNR=24

Secret

3:35 PM

"in two parallel worlds...""

leongz

where did u get the image on the right?

mle

ja, stimmt!

leongz

is there a seperate stream?

mle

content.jwplatform.com/players/JK3Q6HUT-uRmjM0Xa.html (VIRGO)

CR Drost

WOO! They did it. :D

user116211

3:37 PM

Einstein would be happy :P

Slereah

5 sigmas is some good shit

Do we know where the waves come from?

^

Yo momma

Oh snap

Twerkin

3:38 PM

Dat booty's so fine it has a giant quadrupolar moment

guest

The merging of two black holes.

Slereah

is there a paper out about it yet

Secret

guest

This is the FIRST direct evidence.

Secret

The right stream is more techincal the left is more general

Slereah

3:41 PM

can't stream right now

At woerk

skysurf3000

1Gly... In a galaxy far, far away...

mle

Zusammenfassung, I am in German:
LIGO https://www.youtube.com/watch?v=BnQwFtVD5OA
VIRGO http://content.jwplatform.com/players/JK3Q6HUT-uRmjM0Xa.html

FenderLesPaul

journals.aps.org/.../10.1103/PhysRevLett.116.061102

5

^paper link

Slereah

thx

FenderLesPaul

np

dmckee

3:43 PM

No preprint? I'm disappointed in that. I mean, I can log in through fermilab and get the paper, but not everyone has that kind of support.

guest

1000 physicist and engineers took 50 years.

FenderLesPaul

I think there is a pre-print

one sec

dmckee

@FenderLesPaul Link seems to be 404.

Sorry 403. They may be taking anti-flooding measures.

FenderLesPaul

nvm can't find a pre-print

leongz

prl seems to be down

FenderLesPaul

3:44 PM

sorry

the prl link works for me

Secret

dmckee

PRL has been slashdotted.

Secret

Finally, gravitational wave astronomy!

NWard

What a tremendous achievement.

dmckee

That is swweeeeeeettttt.

Slereah

3:47 PM

Eeeeeh

I dunno

The thing is

dmckee

3 m_\sun radiated! Holy cow!

3

Slereah

How often is it gonna happen

Are we gonna have to wait 30 years for another signal

I guess it will be good for funding, at least

It's hard to tell to the moneybags to invest when something has never been detected

NeuroFuzzy

!!!

guest

62 solar masses

dmckee

Note the range. A giga-ly. That encompasses a lot of galaxies.

FenderLesPaul

3:49 PM

@dmckee is the PRL link working for you yet?

Slereah

How often do black hole collisions happen in that range, tho

dmckee

Nada.

mle

National Science Foundation - Live Stream (LIGO Update)

►

Live News Update from Gravitational Wave Detectors

►

0celo7

Am I the only one not excited?

NeuroFuzzy

Yes

Slereah

3:50 PM

I think it's neat

guest

^

ACuriousMind

yes

Slereah

I'm just not terribly excited

3507

@0celo7 Dude you're a GR person.

Slereah

Well yes

But G waves were like

Quantum spaghettification

3:50 PM

Any one got an idea for the reason for the time delay between the detection at the two different sites?

Slereah

v. expected

Emilio Pisanty

Is it me, or is the sound just perfect for a phone notification sound?

Slereah

doesn't change much for GR theory

0celo7

@3507 Meh, all I can think of is how many people they could have put through college with the money they spent on this.

dmckee

@Slereah I've seen estimate but can't recall. Before advanced LIGO they would have been pretty rare. aLIGO is much more sensitive, however.

0celo7

3:51 PM

Does anyone have the cost estimate?

mle

content.jwplatform.com/players/JK3Q6HUT-uRmjM0Xa.html

Slereah

@0celo7 science funding really isn't bleeding the US economy dry

Defense takes up much more money

dmckee

@0celo7 That's exactly where a big chuck of the money went: funding grad students.

0celo7

@Slereah Doesn't make it not a waste.

Slereah

0celo7

3:51 PM

When did I defend defense spending?

leongz

are there actually theories that predict the abscence of grav waves?

Slereah

under 1%

Secret

Slereah

I don't think there's any that are compatible with current observations

0celo7

@ACuriousMind You don't give two shits about GR

guest

3:53 PM

This is EVIDENCE!!!

0celo7

For?

FenderLesPaul

@dmckee let me know if the PRL link eventually ends up working for you

0celo7

Something that has no economic value?

Slereah

Guys let's ban @0celo7

leongz

the whole PRL is still down for me

guest

3:53 PM

EINSTEIN

Emilio Pisanty

@FenderLesPaul I just upgraded from 504 gateway errors to ERR_CONNECTION_RESET chrome errors

0celo7

@Slereah Ask David Z nicely enough and you might get your wish.

mle

virgo-gw.eu

0celo7

@dmckee Please remove that star.

FenderLesPaul

@EmilioPisanty Yeah I can't access the paper anymore I'm getting the same ERR_CONNECTION_RESET error

dmckee

3:54 PM

@Slereah What, again?

John Rennie

@Secret: are you using a different stream? The Youtube one seems very pop science.

Secret

I am actually watching both streams at the same time

with a slight emphasis on the italy one

John Rennie

URL for the tech stream?

ACuriousMind

@0celo7 I do care about major scientific events even if they are not in my field

Secret

@JohnRennie content.jwplatform.com/players/JK3Q6HUT-uRmjM0Xa.html

Emilio Pisanty

3:56 PM

@FenderLesPaul I just got through to the abstract page

dmckee

I'm watching the NSF youtube stream (youtube.com/watch?v=c7293kAiPZw) which is the live conference. And yeah, they've pitched it for the science press.

FenderLesPaul

@EmilioPisanty Can you get through the image verification page?

I keep getting stuck there

Emilio Pisanty

@FenderLesPaul timeout errors there

John Rennie

@Secret Perfect, thanks :-)

FenderLesPaul

@EmilioPisanty I got the paper

is it ok if I upload it here?

0celo7

3:58 PM

I can't open any links anymore

Emilio Pisanty

@FenderLesPaul Yes, it's CC-BY

FenderLesPaul

Ok

skysurf3000

Isn't it strange that there are those two black-holes orbiting one another, and the only thing that we are able to detect is the last second before they collide?

ArtOfCode

@EmilioPisanty BY-SA, actually

0celo7

The link to the paper is completely broken for me

guest

3:59 PM

This is the modern Michelson-Morley experiment

FenderLesPaul

err

how do I upload files on this?

Slereah

heheh

FenderLesPaul

is it just the upload button?

Emilio Pisanty

@ArtOfCode no, it's the full CC-BY

Javier

@skysurf3000 They speed up as they get closer, so the waves are stronger just before the merge

Slereah

3:59 PM

It's One of Those

dmckee

@guest It's a Michelson interferometer, but they don't do the "turn the device" thing that made the MM experiment what it was.

Slereah

A paper with 3 pages of authors

ArtOfCode

@EmilioPisanty aye, but the license on this site is BY-SA.

user116211

0

Q: How are gravitational waves different from space time?

Can anyone tell me how gravitational waves are different to space time and how they affect each other?

0celo7

In more interesting news, I've made the first 10g of that crystal

dmckee

4:00 PM

The instrument is not the experiment. Michelson interferomentors have several uses.

user116211

The influx begins....

0celo7

Turns out 20g will be way too much

Emilio Pisanty

@ArtOfCode It's perfectly fine to republish CC-BY as CC-BY-SA (just not the other way around).

guest

No invite to Stanford for you @0celo7 :P

ArtOfCode

@EmilioPisanty Yeah, just noting. People forget that things get licensed occasionally :)

ACuriousMind

4:01 PM

@FenderLesPaul You can't upload files to chat :P

0celo7

@guest No, the guy who wants me to make it WAY underestimated how much 20g is

Emilio Pisanty

@ArtOfCode Yeah, so you look at the license and you get it right. It's pointless to argue licenses right now though.

Secret

@0celo7 The iron oxide crystal you mentioend previously?

0celo7

The elements are very light

FenderLesPaul

@ACuriousMind well that sucks

:p

0celo7

4:02 PM

@Secret No, this is a Magnesium + Silicon crystal

Secret

I see

0celo7

Don't know why he needs it, I just got the job of making it.

Secret

0celo7

I can't continue with my own work until we get a new furnace.

guest

The numbers in this experiment are amazing :O

Secret

4:04 PM

@ 0celo7 I guess they need silocon to make wafers?

0celo7

@Secret No, the guy is trying to date meteors and we're making meteor-like stuff.

user116211

@Secret Kip Thorne!

leongz

i hate that the two streams are running at the same time. would actually prefer to watch both of them

Emilio Pisanty

@leongz indeed

Secret

you should focus on the italy one, because the youtube can be revisted later\

guest

4:05 PM

^

ACuriousMind

@leongz Well, I'd hope they will both be available afterwards

Emilio Pisanty

@Secret Do we know for sure that they won't re-post the italy one to youtube?

leongz

hopefully

0celo7

They're going to irradiate the MgSiO (don't remember the exact stoichiometry) and see how the structure degrades and compare that to meteor samples

Secret

That I am not sure, because the italy looks very technical, not somehting that will go on youtube readily

@0celo7 Yeah, typical of experiments of that kind they might end up making some glassy stuff of SiO in the process

how does mle secure that italy link?

guest

4:07 PM

So many great accents :D

Emilio Pisanty

> The total energy is what you would get by taking "only" three Suns, and turning them into gravitational waves.

^ wooooot

John Rennie

@guest Dutch isn't a language, it's a respiratory disease :-)

0celo7

Hah

guest

A triumph of global collaboration.

Secret

I am watching both streams because I am an electron

0celo7

4:09 PM

Why so negative, @Secret

John Rennie

@0celo7 Groooooooooooooooaaaaaaaaaaaannnnnn

Secret

I am an electorn, I hate to be confined. Any attempt to do so and you won't know how fast I move

and I end up delocalised through spaceimte

0celo7

Bye. Have to go to class.

Emilio Pisanty

@FenderLesPaul bitbucket / pastebin / whatever?

guest

Hungarian spice :)

John Rennie

4:11 PM

It seems as though the technical stuff has finished. It's all back patting now.

Emilio Pisanty

As long as you give the journal ref & DOI link you're within the license

John Rennie

Well deserved back patting of course!

FenderLesPaul

@EmilioPisanty I can dropbox it

if that's ok

Emilio Pisanty

@FenderLesPaul Yeah, that works

FenderLesPaul

dropbox.com/s/5iraevqdkq97orv/PhysRevLett.116.061102.pdf?dl=0

9

guest

4:12 PM

^great job

John Rennie

@FenderLesPaul grats!

FenderLesPaul

No problem!

I already gave the journal ref above

so it should be fine

leongz

ah.. the benefit of having abbott as your last name

guest

I'm not America, Italian. "I am a physicist"

"A black hole is no longer something written on a page."

Secret

Jiminion

4:16 PM

So, did LIGO record a single event? They just got lucky?

Secret

5.1 sigma lucky, I guess?

John Rennie

@Jiminion aLIGO hasn't been running that long. Unless it was just luck they got an event so soon we should get more detections this year.

Jiminion

I meant they were listening when the 20 ms wave occurred. How often do these things happen?

dmckee

Yes. It's just one event so far. But it's not a statistical measurement so the 5 sigma standard is not applicable.

Jiminion

It's only been running a year or so, right?

Secret

4:18 PM

Q and A in the technical stream alert

guest

It happened 1.3 billion years ago

John Rennie

@Jiminion From Wikipedia: The LIGO Laboratory started the first Observing Run 'O1' with the Advanced LIGO detectors in September 2015 at a sensitivity roughly 4 times greater than Initial LIGO for some classes of sources (e.g., neutron-star binaries), and a much greater sensitivity for larger systems with their peak radiation at lower audio frequencies.[26]

Mark Mitchison

@FenderLesPaul Thanks :)

FenderLesPaul

@MarkMitchison No problem!

Jiminion

So if there are lots of black hole collisions back then? (oops guy is asking similar question)

leongz

4:20 PM

how often are blackhole collisions anyway?

Secret

FenderLesPaul

I think the audio files for the chirp signals can also be similarly accessed.

ACuriousMind

@leongz I don't think we know that, because, as they say, this is the first time we have detected one

Jiminion

Kip Thorne is way smarter than I am.....

Danu

So... I missed it?

Jiminion

4:21 PM

"We should see more in this coming year..."

ACuriousMind

@Danu Yep.

Danu

@ACuriousMind Fuuuuck :P

leongz

@ACuriousMind, is there a way to estimate collision frequency based on the number of blackholes though?

Danu

So was it the 29, 32 merger?

ACuriousMind

@Danu Yes, with 3 solar masses radiated, apparently

Danu

4:22 PM

So exactly as Lubos said in his blog

@JohnRennie Oi!!!

Jiminion

3 solar masses radiated in 20 ms.

@Danu A broke clock is correct twice a day..... :)

Danu

@Jiminion Meh, on low level stuff he's pretty trustworthy.

String theory is his big bias, but okay...

John Rennie

@Danu Sorry :-) Actually I have great affection for the Dutch. When I worked for Unilever I worked in Vlaardingen for a while and loved it.

guest

The Italian president has phoned to congratulate them.

John Rennie

But Dutch is a really hard language. I don't think I ever spoke Dutch without the other person saying "Oh, you're English"!

skysurf3000

4:26 PM

I love how that they estimate the masses of black holes "more or less a few solar masses"... The scale of these things...

user116211

BBC: Mexican Riots. CNN: Trump ; / RT: Officer fainted in discussing the ill-fated F-35 budjet.

user116211

WTF!!

Secret

guest

50 million CPU hours of data analysis

user116211

WoW!! Ultimately, got one discussing LIGO . RT: It was actually Soviet Physicists who discovered LIGO.

user116211

4:31 PM

What???

vzn

(rats just missed the chat session.) anyway was telling some kids about gravity waves and comparing the detection to LHC. told them that maybe ~$1B has been spent on detectors for gravity waves. (total SWAG on my part.) does anyone have any idea how much has been spent on equipment over the years? presumably on detectors not all involved in this current discovery. anyway, another huge FTW for "big science"...

Secret

HELP MY STREAMS ARE FAILLING

ok it works again

vzn

also some have mentioned this is a "for sure" nobel prize... but who to award it to in particular...? quite a quandary...

user54412

@JohnRennie Though I'm not against renaming them in order to remove a couple syllables

Jiminion

"comparing GW form, and einstein equations, can tell if waves were distorted, which could support non-zero rest mass in graviton". 10-55 grams.

Emilio Pisanty

4:38 PM

So what's that in eV?

John Rennie

@ChrisWhite No don't do that. Correcting people when they use the term gravity wave is the GR equivalent of correcting people's grammar. Very annoying but hugely entertaining :-)

vzn

so are gravitons basically quantized gravity waves? (havent seen announcement) ... they arent talking about gravitons are they?

Jiminion

@vzn I'd say KST and the Italian woman and maybe the Russian(s) that proposed it. Are thye limited to 3?

@vzn KST just said something about them. (I guess it's in the paper -- the speculation)

vzn

@Jiminion higgs particle nobel only awarded to a few, dont recall details, but its a rough precedent.

John Rennie

@vzn no, though a gravitational wave is in principle a coherent superposition of gravitons.

Secret

4:39 PM

I missed that important QA in the technical stream (because the answerer is muffled voice) How to explain to a non physics person why today's findings on gravitational waves is so important, is it just because of astronomy?

Emilio Pisanty

So 10^{-23} eV wolframalpha.com/input/…

Jiminion

@Secret The short answer is that it just verifies Einstein in a different way.

guest

Italy looks like the place to be for this kind of research @ChrisWhite :P

Jiminion

@Secret The long answer is we can find out more about gravity (gravitons? maybe?) and perhaps something about the earlier universe where black holes were colliding, apparently.

vzn

@Secret there are many reasons (see recent nature article with "questions this could answer"), it opens up a whole new branch of experimental/ observed astronomy. will be able to tackle some of the big questions like nature of universe expansion, what holds galaxies together, birth/ death of galaxies, etc... cosmic evolution etc

Secret

4:41 PM

Can't wait for them to find another signal that involves intermediate mass balck holes

user54412

@guest uh why?

guest

They have more government interest.

Secret

:27500693

I see, thanks

user54412

@guest The US has far more government spending

Secret

The Washington stream has ended

vzn

4:44 PM

24 hours ago, by John Rennie

http://www.nature.com/news/gravitational-waves-6-cosmic-questions-they-can-tackl‌e-1.19337

user54412

Did anyone else catch the "These are not Hollywood animations but actual simulations" comment with Kip in the room?

Danu

@JohnRennie That's not the Netherlands, though ;)

mle

vorbei auch in Italien

ACuriousMind

@ChrisWhite Hehehe...didn't realize that could've been a jab at him

user54412

@ACuriousMind not sure it was meant to be, but the audience I was watching with all laughed

Secret

4:46 PM

leongz

i thought interstellar used actual equations

Secret

The Italy stream has ended

vzn

@ACuriousMind wasnt kip thorne involved in doing the interstellar movie cgi/ simulations as consultant? (iirc) it was some big-name physicist... (good wired article on that)

ACuriousMind

@vzn Yes, exactly

guest

@ChrisWhite did you take any of his classes?

John Rennie

4:46 PM

@Danu It isn't? Wikipedia says it is. Or is this some obscure Dutch in joke that I'm missing? :-)

user54412

yes, but those simulations were (1) trivial and (2) altered for cinematic purposes

user54412

@guest he was retiring around then; saw him around campus plenty though

vzn

@ChrisWhite not exactly trivial afaik (hollywood cgi chews up a lot of manpower/ cpu cycles), but agree with the cinematic emphasis. (ie not meant to be highly realistic or accurate.)

user54412

well, trivial compared to merging black holes :p

John Rennie

@vzn amazon.co.uk/Science-Interstellar-Kip-Thorne/dp/0393351378

user54412

4:48 PM

the movie was just ray-tracing in kerr spacetime, which amounts to numically intergrating a couple ODEs

Danu

@JohnRennie Vlaanderen = Belgium

John Rennie

Vlaardingen not Vlaanderen

Danu

Hahhaahha

Dat epic Dutchness fail

I'm so sorry. That is in the Netherlands.

user54412

@Danu More Dutch, less Murican

vzn

is kip thorne connected to this announcement somehow? hes at the press conference?

user54412

4:49 PM

@vzn yes

user54412

he spoke

John Rennie

@Danu You had me wondering if I'd been to one too many cafes for a while there

leongz

he's the co-founder of LIGO

user54412

he's been the theorist pushing for LIGO since the 70s or earlier

user54412

@ACuriousMind there was also the "Einstein was not just a theorist" ;)

CR Drost

4:51 PM

I'd love to see a simulation of black holes which includes orbiting rings of matter that are generating all sorts of radiation from infalling mass; did Interstellar have that?

John Rennie

@Danu unilever.com/about/innovation/our-r-and-d-locations/…

ACuriousMind

@ChrisWhite Yeah, I heard that

CR Drost

I like to imagine that black holes would actually be pretty bright and streaky and kaleidoscopic.

Secret

gotta sleep guys. IT's 3:51 here in Syd and I have to wake up at 7:00

Danu

@JohnRennie So what sandwich spreads were you working on?

CR Drost

4:52 PM

Then again maybe all of those effects are redshifted into oblivion.

user54412

@CRDrost that uh... sounds like my thesis

CR Drost

@ChrisWhite: got a linky?

user54412

my unfinished thesis :p

CR Drost

Heh. Ph.D. or Master's?

user54412

PhD

user54412

4:54 PM

also, I don't have a team of Hollywood animators to make my movies look pretty

CR Drost

Cool. I'd like to go back and get one of those some day, kudos to you.

My problem is that my Master's thesis was not very good leading me to kind of rage-quit academia.

guest

Thanks for the great link @mle :-)

mle

Bitte!! ;)

@guest, Bitte! ;)

Emilio Pisanty

@ChrisWhite Do we have good analytical waveforms for the detection?

Or is there a clean way to get the sound they played at the beginning?

vzn

@CRDrost its a huge open question whether black hole radiation is significant and/or can be detected afaik. this is a big question that hawking tried to tackle decades ago, part of his fame. he was (nearly?) 1st to propose maybe they are not invisible & radiate something.

Jiminion

4:58 PM

theatlantic.com/science/archive/2016/02/…

CR Drost

@vzn: well Hawking radiation is also interesting but different, I just want to see the radiation due to infalling matter.

vzn

@CRDrost so do a lot of scientists...?

CR Drost

Much more classical in nature.

I mean in a simulation. :P

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