Comments for Cosmic Variance

Comment on This is What Observing Feels Like by chintan

chintan — Mon, 22 Mar 2010 12:19:57 +0000

Catch bollywood celebrity in IPL. @ http://iplrock.blogspot.com/2010/03/bollywood-celebrity-in-ipl-2010.html

Comment on Shakespeare for Children by CW

CW — Mon, 22 Mar 2010 11:56:51 +0000

I like to think there is a magical island somewhere inhabitated with the balloons that have escaped the clutches of a child’s hand. Live free, balloons. And live well. *sniff sniff*

Comment on Shakespeare for Children by Humble reader

Humble reader — Mon, 22 Mar 2010 09:31:31 +0000

Perhaps there was a failed toplogical sphere-torus transition,
or a local transient inflationary event of the boundary followed
by failed budding off of a new ballon-verse. Tragic indeed, but
on the bright side 10^500 ballons ought to yield one robust enough
to this sort of thing.

Comment on Shakespeare for Children by Mandeep

Mandeep — Mon, 22 Mar 2010 07:02:57 +0000

Hmm — i can guess deflation is one of the sad latter acts, but am not sure of the other..

Comment on Highest energy ever by Jesse M.

Jesse M. — Sun, 21 Mar 2010 23:45:29 +0000

Kessler, it's unlikely micro black holes will actually be created in these collisions in the first place, that would only be possible in models with large extra dimensions which are a speculative extension of string theory (and string theory can itself be used to derive the prediction of Hawking radiation as I understand it). But more to the point, even if micro black holes are created in the LHC, that would imply micro black holes are also being routinely created by cosmic rays whose energies can sometimes be even higher; so even if Hawking radiation is wrong, there must be some physical factor that prevents such micro black holes from eating the Earth, since if there wasn't the Earth (and every other massive body in the universe, like stars) would have been eaten long ago! That logic seems pretty irrefutable, can you suggest a reason micro black holes created by the LHC would behave any differently than those created by high-energy cosmic rays?

Comment on Highest energy ever by JD

JD — Sun, 21 Mar 2010 22:01:54 +0000

Also, I have to echo Jennifer West’s comment. Unlike politics, high-energy physics doesn’t care about equality. Some people’s opinions ARE worth more than others, because they’ve spent years studying the phenomena in play. It’s great that people are getting interested in frontier science, but it’s bad that they’re taking misinformation as truth.

The LHC is a tool which whill help us determine which, of many different models, is the correct one. Those models have been published many, many times. They’ve been read, studied, criticized. If you’re going to say that the LHC is endangering the Earth and you want to be taken seriously, do as the high-energy physicists have done: show your work. So far, I’ve never seen anyone in the LHC-is-dangerous camp do that, but I’ve seen plenty of people show that it’s safe.

Comment on Highest energy ever by JD

JD — Sun, 21 Mar 2010 21:51:05 +0000

Kessler,

Hawking didn’t admit that black holes don’t radiate away energy and evaporate. He admitted that Hawking radiation contains the information that went into the black hole in the first place. Please get your facts straight before fear-mongering.

More information is available in Leonard Susskind’s book:

http://www.amazon.com/Black-Hole-War-Stephen-Mechanics/dp/0316016403

(which is an excellent read for laypeople, but which seems very basic even to this junior undergrad.)

Comment on Physics on TV by Steve

Steve — Sun, 21 Mar 2010 20:59:42 +0000

That was wonderful! And she didn’t even have to read her talking points from the palm of her hand.

Comment on From Eternity to Book Club: Chapter Ten by Sean

Sean — Sun, 21 Mar 2010 15:16:21 +0000

“Large” refers to the size of the entropy fluctuation, which does have a scale — the maximum entropy of our observable patch is something like 10^120, and the actual entropy is something like 10^103, which is enormously smaller. Put another way: to explain us, you don’t need 100 billion other galaxies.

Comment on From Eternity to Book Club: Chapter Ten by P

Sun, 21 Mar 2010 14:58:20 +0000

Sean: “Clifford, it’s certainly possible that a downward fluctuation in entropy could create conditions like we see in the early universe. However, it would create much smaller fluctuations much more often. So this theory predicts very strongly that we should be in a tiny fluctuation, not a large one. Therefore, it’s ruled out.”

That’s a very weak argument, which certainly cannot rule it out. Whose to say our fluctuation is “large” and not “tiny”? There is no such thing as an universal scale, the visible universe can be the whole there is or it can be an infinitesimal part of some superstructure.