Einstein, Black Holes and Cosmic Chirps - A Lecture by Barry Barish
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- čas přidán 15. 06. 2016
- Albert Einstein’s theory of general relativity, developed 100 years ago, predicts the existence of gravitational waves. In February 2016, the Laser Interferometer Gravitational-wave Observatory (LIGO) became the first experiment to observe gravitational waves, created by two black holes spiraling into each other. The discovery became known as the chirp heard around the world. Four month later, a few hours before this public lecture, LIGO announced the discovery of a second signal. This lecture, given by Dr. Barry Barish, LIGO director from 1997 to 2006, explains the physics of gravitational waves, the detection technique used by LIGO, the observations made and the implications these discoveries have on our understanding of the cosmos.
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Great story teller. The history of scientific discovery is fascinating and I was captivated at 5am listening to this.
Id really like to thank fermilab for putting these up. I love you guys for your videos. Thanks a lot.
It's been four years and they still haven't responded to you, a simple "you are welcome" is all we needed.
You’re welcome 😉
Absolutely excellent. Thank you so much for publishing this.
This is very nice, thanks. I'm not in the field but can understand the basics of the presentation and that is partly a testament to the good presentation technique.
Having gravity wave detection devices across the earth that are very sensitive can triangulate events and possibly much more in the future.
It's amazing how several decades of work culminated in success, and the engineering out of multiple issues was key to success.
Fascinating! Thanks much for posting!
Phenomenal lecture!
Wickedly detailed, and yet still super-dummed-down, such is the complexity. Physics genius' that truly deserves it's place amongst the greats. Even Einstein said it'd never be done......
+Fermilab Can you please add the links listed at 1:07:00 that lead to the papers (PhysRev, arXiv, etc.) that published the detections made by LIGO?
I like the lectures that are coming out lately.
1:04:20 I've heard about LISA and BICEP 2 (- and this was about LIGO obviously), but now I'd like to learn about "Pulsar timing arrays"...
1:03 :: Lecture start
This is a fantastic presentation by a great man and the technology they developed is amazing.
Thanks Fermilab! The scientist are real superheroes!
This was a great layman's explanation of ligo.
Thanks Fermilab .....
The correct Answer to the question at 1h 22.40s is the same as Faraday's answer to : " Of what use is your discovery in electromagnetism?"
Faraday's answer Was :" "Of what practical use is a baby?"
Some day, my lord, you'll be able to tax them both!
is the delay between the two facilities always 10ms? what if the wave passes somewhere in the middle or at an angle?
Gravity waves are not 2D like waves on the ocean, they are 3D waves in all of spacetime.
A black hole isnt a hole. It has no dimension. What we "see" is an anomaly of two or more converging processes of dense matter colliding, giving the effect of an empty space. What is "in" that "space" is simply the sum of the reaction to the competing particle masses.
I can understand mass loss when you fuse together two nuclei, for example, but can someone explain how mass is lost when fusing two black holes? I get that the mass should generally be lost by way of the energy needed to produce gravitational waves, but given that these are singularities, how can that energy escape?
Is it just incorrect to say that the black holes had initial masses of 36 and 29 solar masses, and that those mass quotes instead only made sense when considering the overall system of both black holes?
In the section where the lecturer talks about Einstein's papers on gravitational waves, he explains that Einstein saw a parallel between his equations and the equations for electromagnetism. When mass is lost in the process of fusing two nuclei, its equivalent in energy is radiated in electromagnetic waves. The parallel is that when mass is lost in the process of fusing black holes, its equivalent energy is radiated in gravitational waves.
There are other ways to create electromagnetic waves (other than nuclei fusing), such as is done for radio transmissions, with an appropriate oscillation of electric charge. The creator of the electromagnetic equations (Maxwell) also predicted waves before anyone knew they existed. The lecturer illustrates an appropriate way of oscillating masses so that they will produce gravitational waves, which unfortunately are far too weak to detect. But in the conditions leading up to the fusing of two black holes orbiting around one another, the waves are so strong the waves are detectable.
I guess the waves are created in a tiny time before the holes unite. It is not after the two holes join. It is the orbiting and not the joining itself.
I guess one has to admit that mass must somehow lie partially outside the event horizon (in the gravitational field), as well as inside, if nothing, including mass, can come back out across the event horizon. But then the same must be true about objects without an event horizon.
Dr. Barish's laser pointer doesn't appear up on the view that tens of thousands of people get on CZcams. Is there a simple, practical technology that would allow for these important indications to show up on the video here?
Agreed; this is true, not just of Barish's talk, but of many lectures/presentations on You Tube: when the speaker is giving a presentation, whether it's a Power Point or with slides or videos, stills, etc. you can hear that they're pointing something out a certain thing on that picture, e.g., a graph of some sort, a chart or a picture of a big section of the sky/space & the stars of which they're speaking, but, though you know they're referring to a particular thing, it can be frustrating when you cannot see what it is they're referring to!!
well now is a perfect occasion to learn about complicated degree level phyisics rather than revising for GCSE level French
Need preliminary lectures but very very important
Leverrier predicted the position of Neptune not Uranus. Uranus was discovered by William Herschel about 65 years earlier.
I was hoping they would zoom in. Turns out they already did, I just had to wait for the light to reach my eyes
I have no idea how someone could prefer to watch 'The Blunderverse' over this.
Nothing short of incredible work! So sad humans squabble so much, they can be so smart if they try.
7:50 I'm guessing that I'm not going to be the first person to notice that this lecturer doesn't know his Uranus from his Neptune?
when you work with black hole theory, the planets are basically all just the same as each other: irrelevant
48:10 into the lecture he says "eV per square centimeter", instead of "eV divided by speed of light squared"... when speaking about the mass of a hypothesised graviton. How does this happen, coming from such a high profile scientist? Other than that I liked the presentation.
Sometimes people misspeak or make typos (I didn't go back to find out which one). Incidentally, "typos" is one reason I lament the general lack of mathematical formula support in text editors. If you could just copy the formula from Matlab (or whatever) and paste it into your presentation software, it'd eliminate a source of error.
nomeegal Many physicists commonly shorten momentum and mass terms to just eV and expect that the rest is implied and understood by context. It doesn't seem right to outsiders but it's just a useful conversational shortcut. At no point did he not know the actual dimensions.
Time dilation while travelling is actually questionable from non isotropic gravitoetherton super fluid give uncertainty in calculation and you end up with a wrong judgement.
I understood you up until "from"
The GPS facts after the 13 minute mark are wrong. GPS flies at half-geosync, 14,000 km/hr, almost a full third slower than 24 kmph shown. The 7 microsecond per day difference for SR is a direct result from the Lorentz transform and easily verified.
Are there as many gravitational waves as black holes?
Wave events occur with each merger of 2 black holes; Or neutron stars; or one of each; Probably other objects too.......space-breaking physics!
Gravitational waves are ubiquitous. We just can’t detect them unless they’re extremely strong like two ridiculously massive bodies flying around each other at a “large” percentage of the speed of light.
Can any one tell, why black hole is circle or ball shape in visual effect.Is it is the true shape.If yes why it is in that shape...? Even light will not escape from black hole, on the edge of space where black hole starts ....the pulling speed is more than light speed...from there to inside black hole the measurement of speed change from light years to some other new unit of measure...
Black holes are spherical because this is the lowest potential energy state. Rotation might give a bulge but I don't know.
11:53 you are not seeing something that isn't there.. you are seeing something behind something you cant see.
good morning
48:09 Gravitons don't exist though, right? Because gravity can't both be caused by geometry AND particles... right? Or is this still extremely debated?
Roughly speaking at least by some interpretations of modern physics all particles are just convenient expressions of fields. That's why they expected the existence of the Higgs Boson as an indicator for the Higgs field. The idea of the graviton changed a lot over the decades with the change of ideas about gravity, I think, but in essence given that something is still causing the effect of gravity there might still be an expectation that on the quantum level it can be found in a particle.
But it is a special case as gravity is shaping spacetime and most other effects happen within that framework and this is a level deeper than that.
I think I stuck out my neck out far enough though because that is probably all very speculative science physicists are still arguing about on all levels.
Just to add to that. The LHC results from the last run should be presented in July-August of this year. If evidence that gravitons exist has been found at the LHC we'll know then, if not, it's probably not going to be possible to determine if they exist with the LHC and we'll have to wait for a more powerful particle accelerator to be built. The successor to LHC is going to be built in Japan and should be completed around 2026.
In the third grade, Einstein ate his crayons.
In the briefest of an instant after the big bang , was the universe infinite?
Good question 🤔
You can't have multiple measures of time or age for the same universe. Time is an expanded fabrication and you can't use expanded time as a valid measure of historical time. Time runs at different rates in different places in the universe and there is no absolute measure of time or distance in the universe. The singularity from where we supposedly came from is no time and no space so the universe is closer to no time than it is to billions of years. You can't see into a black hole because it is literally too far away for us to see because of distance dilation or length contraction observed for the first time by way of gravitational waves.
The use or benefit of interferometers would be in the way of learning more physics and knowing in advance about the various phenomena that we might encounter coming from space. It will likely disprove dark matter and dark energy as well. Already, we have learned that black holes are more massive than previously thought (which I already knew).
"disproving" dark matter/dark energy makes no sense. What the goal is, is to be able to find out just what it is that makes up 26% & 69% of the mass of the universe; the proportions that the Planck spaceprobe recently came up with, which turned out to be a bit different from what the WMAP mission previously came up with. So just saying this off-the-cuff, uninformed stuff really shows a lack of understanding and/or arrogance on your part.
Tires have black holes and so do chocolate donuts. That's how physicists think.
his voice is seem to like Steve jobs.
I think me might have a working model of time now
einstein never said blackhole exist, and hawkings even said it himself, blackholes dont work like a whirlpool in space -_-
Nice for sleeping👍
how can he say interferometer with ninety percent accuracy but miyror with only fifty?
I could have told you there is a lot of room for a lot of matter involved in a black hole.
Maybee black holes are new universes and dark matter and dark energy is maybee vakuum
Additional info on Dark Matter:
czcams.com/video/L4KDCCLTriU/video.html part 1/108
he knocked me over the head in the shower and stole my ideas...
Very funny, well done!
How does all this knowledge benefit mankind?
No
It looks just like my dog's nose...
It is your dog's nose.
Gravity does not exist
neither does your intelligence.
HA hahahahaha!!!! LMAO!!
Gravity is the effect of things spinning in space time fabric. So as an effect it definitely does.
I wonder.....was he bald and so angry-looking when it all began........
it sort of funny when Canadians say aboot but just annoying to hear yanks say miiya although this guy better than most I will admit.😇
For god sake take care of the sound of the videos! Horrible to listen to this with that kind of sound!
He’s not a scientist he’s a thief.
He didn’t come up with anything.
Taking credit for other peoples achievements.
Actually, Eddington's data was _clearly_ fabricated, and although that doesn't nullify the validity of GR in the least, it does mean we need to stop referring to Eddington's falsified measurements as evidence for GR - it is most certainly not.
Any amateur astronomer could tell you that an angular resolution of 0.01 arcseconds (which is what Eddington claimed when he published his results) is absurdly impossible even with the best field astronomy equipment today, much less Eddington's 19th century equipment. He published deviations of the positions of stars close to the sun before and during a solar eclipse which agreed with GR to a level of precision which was not even close to being realistically possible under the conditions of his "experiment." Eddington had also already come out publically as stating he didn't think GR needed proof and that it was self evident - the only reason he bothered to fake his data was because he wanted the fame, and unfortunately scientists are still giving him what he wanted - to the detriment of the integrity of the scientific process.