Wednesday, February 10, 2016

Who Will Win the Nobel Prize for Gravitational Waves?

When the announcement come of the direct detection of gravitational waves comes, probably tomorrow, should it win a Nobel Prize? 


This is very basic physics, core-of-the-Universe type stuff. Something that will be remembered and celebrated 50, 100, 500 years from now.

Clifford Burgess, a theoretical physicist at the Perimeter Institute for Theoretical Physics in Ontario, said:
"If this is true, then you have 90 percent odds that it will win the Nobel Prize in Physics this year. It's off-the-scale huge," Burgess told Science magazine.
So who should get the Nobel Prize?

I've always thought a nice Prize about black holes would be to jointly award it to Stephen Hawking, Kip Thorne, and Roger Penrose, all of whom made fundmental contributions to gravitation on the theoretical side, especially to the properties of black holes.

Kip Thorne in 1972
But of the three, only Kip Thorne would get a Nobel Prize for gravitational waves. There is a great passage in his book Black Holes and Time Warps (well worth reading, with more flavor than Hawking's books), where he writes about walking around Pasadena, California late one night in 1976, trying to decide if he should commit to building a gravitational wave detector and all the work, scientific, political and organizational, that would entail.

He did decide to go for it, so this discovery is his as much as anyone's. He worked hard at it for a long time, and LIGO would probably not have come about without him. So he definitely deserves a piece of the prize.

Who else? The Nobel Committee has always been reluctant to award the prize to an organization as a whole, without giving part of it to an individual who led the projects -- think Al Gore and the IPCC, or Carlo Rubbia and CERN -- but I think this should come to an end soon. Collaborations are just too important now, especially in experimental physics -- the projects are too big, and the influence of any one person too small -- for that award structure to continue.

So I'd like to see half the prize got to Kip Thorne, and half to the LIGO research and engineering team, both in Hanford and Louisiana, of course.

If LIGO announces a detection tomorrow morning, this prize could be awarded as soon as this fall, depending on what collaborating evidence might exist, from astronomers or other, smaller, less resolute gravitational detectors around the world. Though I doubt many physicists would immediately doubt the announcement of a detection.


JoeT said...

David, I just read your excellent article in Physics World. Very clearly written, by the way. Do you know if in fact the gravitational wave discovered was a binary black hole coalescence? Was it just one event or a series of events. Thanks!

Unknown said...

If the Higgs Boson garnered a Nobel Prize, then I do not see why this should not.

Cesar said...

What about Rainer Weiss who conceived of LIGO and had to talk Kip into it? :)

Layzej said...

Greg Laden brings up an interesting point: "I don’t like the fact that the device was turned off and upgraded, then, very soon after being turned on, found a gravitational wave, and apparently hasn’t found another since then. I’m worried that this is similar to when CERN detected faster than light neutrinos. Everybody knew there were no faster than light neutrinos, but the instruments detected them anyway. Eventually, it was discovered that something was going on with the way the instruments were wired up that made the detector wrong." -

We know there should be no faster than light particles, so there would have been a great effort to find an alternate explanation. It sounds like the LIGO folks were extremely cautious, but I wonder if the fact that we know gravitational waves should exist would have some impact on the level of scrutiny.

David Appell said...

Joe, I'm sorry I didn't get to your question sooner.

Yes, the gravitaional waves detected from LIGO were from a black hole coalescence. Each hole was about 30 solar masses, plus or minus (not exactly; that's off the top of my head).

It was just one event. In fact, detectable gravitational waves (at LIGO) only come from the last second of the coalescence, when the gravitational field is very strong and changing fast. IIRC, the grav wave detected by LIGO was only about 10 milliseconds in duration. That will be typical of anything else LIGO detects, according to numerical calculations done via general relativity.

Equally satisfying is that these detailed calculations predicted the wave seen. This is the first time "strong field" calculations of Einstein's equations have been verified. All other examples -- the deflection of starlight, the change in the perihelion of mercury, gravitational redshift, etc -- were done only as first-order perturbations to Newton's law of gravity.

So it's quite amazing that Einstein's theory passed this strong-field test.

David Appell said...

PS: I also wrote a feature article about numerical general relativity, awhile back:

"Relativity's New Revolution," Physics World, October 2011.

It has very nice figures, if nothing else.

David Appell said...

Cesar: Yes, I thought about Rainer Weiss after I wrote this. You're probably right. But I think it'd be a shame if the LIGO project team didn't get at least a piece of the Prize.

David Appell said...


I don't agree with Greg Laden, because the previous versions of LIGO were simply incapable of detecting gravitational waves of the sort that were expected. They were really 10+ years of enhancing a basic machine and getting all its parts to work together.

It may be a little surprising that advanced LIGO found a GW so quickly. Or it may be that there are lots of sources out there that the previous versions of LIGO just could never see. I'm sure lots of people are looking at the odds that this particular wave was detected, and what it means for the number of detectable events out there -- whether they are more like a few per year, or more like dozens per year, or hundreds. No one really knows.

I wouldn't be at all surprised if LIGO is now busily analyzing other signals they saw.

Several years ago, before I know anything about LIGO, I wrote and asked one of their project managers if the fact that enhanced LIGO (the machine as of several years ago) hadn't detected any GWs, if that meant they didn't exist. He said, absolutely not, that they really didn't expect to detect anything (any detection would have been a big surprise), and that everyone was waiting for Advanced LIGO. They had a lot of expectations about where the signals were and weren't.

The detected signal was a pretty close match to theoretical expectations. That's a stronger result than just measuring a time to determine the speed of neutrinos. And I'd bet that neutrino team really regrets letting that all get away from them and their speculating, under pressure, about what their measurement might mean. They really had a lot of verification to do before they should have announced, and they didn't do it. They got caught up in the moment.

By contrast, LIGO looked at their signal for about 5 months before announcing.