Comments on: Future cosmology Nobels

By: « An American Physics Student in England

« An American Physics Student in England — Tue, 03 Oct 2006 15:53:05 +0000

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By: Nobel Prize to Mather and Smoot for CMB Anisotropies | Cosmic Variance

Nobel Prize to Mather and Smoot for CMB Anisotropies | Cosmic Variance — Tue, 03 Oct 2006 15:41:03 +0000

[...] The Nobel Prize in Physics has been awarded to John Mather and George Smoot, for their discovery using the COBE satellite of temperature anisotropies in the cosmic microwave background. These tiny fluctuations in temperature provide a high-precision snapshot of what the universe was like 380,000 years after the Big Bang. They originate in density fluctuations that grow into large-scale structure today, and subsequent careful examination of the properties has revealed a tremendous amount about our universe. It’s a very well-deserved Nobel, which was top on my list of cosmology prizes back in May: The 1992 observation of CMB anisotropies by NASA’s COBE satellite was the first step in a revolution in how cosmology is done, one that has come to dominate a lot of current research. Subsequent measurements by other experiments have obviously led to great improvements in precision, and most importantly extended our understanding of the anisotropies to smaller length scales, but I think the initial finding deserves the Nobel. So to whom should the prize be awarded? On purely scientific grounds, it seems to me that there was an obvious three-way prize that should have been given a while ago, to David Wilkinson, John Mather, and George Smoot. Wilkinson was the grandfather of the project, and was the leading CMB experimentalist for decades. Mather was the Project Manager for the satellite itself (as well as the Principal Investigator for the FIRAS instrument that measured the blackbody spectrum), while Smoot was the PI for the DMR instrument that actually measured the anisotropies. Unfortunately, Wilkinson passed away in 2002. Another complicating factor is that there were various intra-collaboration squabbles, leading to books by both Smoot and Mather that weren’t always completely complimentary toward each other. Still, background noise like that shouldn’t get in the way of great science, and these guys definitely deserve the Nobel. [...]

By: Shaw Prize for the Accelerating Universe | Cosmic Variance

Shaw Prize for the Accelerating Universe | Cosmic Variance — Mon, 26 Jun 2006 13:56:03 +0000

[...] The Shaw Prize in astrophysics has been awarded to Saul Perlmutter, Adam Riess, and Brian Schmidt, for discovering the acceleration of the universe by measuring the Hubble diagram using Type Ia supernovae. The Shaw Prize is relatively new, having first been given in 2004, and is awarded in three areas: Astronomy, Mathematical Sciences, and Life Sciences and Medicine. It comes with a total of US$1 million, split between the three recipients. Competitive with, although not quite as much as, the Nobel prize… Brian Schmidt and Saul Perlmutter come to blows over whose universe is accelerating faster [...]

By: hongbao zhang

hongbao zhang — Mon, 29 May 2006 05:23:15 +0000

Some naive comments:)

I do not think anisotropy and acceleration will be worth of Nobel, Because there are too many problem to be resolved. In other words, these discoveries may be not surprising if we pay more attention to our theoretical framework where our so called discoveries have been explained. It is possible that we have not found any new physics from these discoveries. I think it will take us more time to check.
In addition, If Guth could be provided with Nobel, Hawking may be in a better position to win the Nobel.:)

By: Scott

Scott — Sat, 27 May 2006 02:36:12 +0000

Rob (of comment 10): Santa Cruz is not southern California.

By: Rob Knop

Rob Knop — Fri, 26 May 2006 03:12:28 +0000

Here’s the link to the Knop 2003 paper that I cited above:

http://brahms.phy.vanderbilt.edu/~rknop/research/papers/hstpaper/

By: Sean

Sean — Fri, 26 May 2006 00:18:47 +0000

Rob, I closed the tags, but your link was eaten, if you want to re-post it. Note that stuff beginning with “http://” is automatically turned into a hyperlink, even if you don’t include the html explicitly.

And yeah, detecting the neutrino background would be great, as would finding evidence for Hawking radiation. Neither seems especially promising at the moment.

By: Rob Knop

Rob Knop — Fri, 26 May 2006 00:13:18 +0000

Re: the cosmic neutrino background, it would be really cool if we detected that. We’re quite a ways off from that right now, though. It takes ginormous detectors to make reasonable measurements of neutrinos from the Sun, the atmosphere, and nuclear reactors right now…. And the CMB neutrinos are all *really* low energy, which will make the whole thing a lot harder.

But… damn, that would be cool if we saw that.

-Rob

By: Rob Knop

Rob Knop — Fri, 26 May 2006 00:12:07 +0000

Damn — can one of the mods fix the post I just made? I screwed something up in closing a link tag. Feel free to delete this comment if you manage to fix it.

Sorry :/

-Rob

By: Rob Knop

Rob Knop — Fri, 26 May 2006 00:11:04 +0000

can anyone give the two- or three-sigma confidence interval for some cosmological quantity that parametrizes acceleration â€” a-double-dot/a, or Omega_Lambda

I did it back in 2003. This is based on the SCP supernovae through about 2001. (Well, not all of them, but the ones from the Perlmutter 99 paper plus an additional HST-observed 11 that were the main topic of that paper.) I did lots of fits, and didn’t always assume Omega_Total=1. I did, in practice, always assume *either* that Omega_Total=1 *or* that dark energy is Vacuum energy (i.e. w=-1), although just for kicks at one point I even relaxed that. (There, there was more probability for Omega_w->0, but it also needed values of w that were way less than -1, and as such are really scary.)

Depending on which fit you want to believe, the probability that Omega_Lambda>0 assuming that w=-1, but *not* assuming that Omega_Total=1, is higher than 0.99. (My two favorite fits have 0.9997 and 0.9974, respectively.) This is based on that dataset, which is a few years old now. If you got to the datasets in the ESSENCE and CFHTLS papers that have come out in the last year, I susepect you’ll get an even higher probability for Omega_Lambda>0.

Of course, lots of people have tried to say that there are systematics in supernovae that are causing this…. It’s always something to worry about, but so far none of those arguments have held up. There have been various complaints about dust reddening– those have by and large gone away (indeed, I sort of think between the Knop 2003 and Sullivan 2003 paper they were slain). There have been “grey dust” models, but you need some pretty wacky modesl of grey dust to get anything to work. Supernova Ia evolution is a big question mark, but even there you have to do a lot of fine-tuning to get things to match with some of the work Adam Riess has done with z>1 supernovae, together with the lower-redshift ones.

I think it’s safe to be pretty sure that either the Universe is accelerating and thus has Dark Energy in it, or we’ve found something like the luminiferous ether that will shortly lead to a deeper understanding of Physics, brought to you by find theoretical minds like those of cosmicvariance.com. (Me, I’m just a data monkey.)

-Rob