Thursday, January 12, 2006

CSL-1 is not a cosmic string

I received two messages about this sad news almost simultaneously - from Mark Jackson and Joe Polchinski. Guiseppe Longo (and maybe his collaborators) has downloaded the pictures from the Hubble Space Telescope, and it is "just a pair of interacting ellipticals sitting in a rather faint cluster," not a cosmic string.

He promised various people to be informed quickly, which is why you are informed so abruptly by a leading physics blog (one hour before our colleagues at Cosmic Variance) even though the news is not the most thrilling outcome you could have hoped for.

At any rate, it is time for science-haters to celebrate. ;-)

Some people ask how the picture would look like if there were a cosmic string. I think that it would look like this one:

Let me add to the main text that Joe Polchinski's estimated probability that a cosmic string could be seen was something about 10%. Joe would have therefore told you a smaller number for this particular case, I think. In this sense, it is not a surprise that the conjecture that CSL-1 was a cosmic string was falsified. While it is not a surprise, it is still a disappointment.

A confirmation that it is a cosmic string would have meant much more obvious progress. This observation has falsified one particular case but it has not falsified the idea of cosmic strings in general. And just to be sure: it has of course told us nothing about the validity of string theory as a fundamental theory.


  1. No, Lubos, what is worth celebrating is that this time, serious experimental science wins over wild speculations of pure crackpot ideas.

    The cosmic string business, brewed to gigantic proportion based merely on pure speculations on one single odd image which contains two insignificant tiny spec of dots each attributable to no more than a dozen stray photons who lost their ways in the universe. That cosmic string business, was never science to start with! Real science is based on solid, credible, repeatable, unbiased and none-disputable objective observations and water-tight derivation of logical reasoning.

    It's entertaining to see what kind of big proportion the CSL-1 business was blown up to, before it un-eventfully burst like a soap bubble. It's predictable that string theorists would continue to blow such cosmic soap bubble because they enjoy it. Never mind CSL-1, there will always be CSL-2, CSL-3, all the way to CSL-10^500, one of those gigantic cosmic bubbles will contain cosmic strings.


  2. You completely misunderstand the sociological structure of science related to these observations.

    Most string theorists have no idea what CSL-1 was and they don't care.

    The hypothesis that we may observe cosmic strings in the skies has been around long before it was shown that these cosmic strings could be identified with strings from string theory. Many people who have nothing to do with string theory have worked on this entirely plausible possibility.

    This finding from HST is first of all a disappointing news for those who are directly working on this subject - Sazhin, Longo, et al. - but more indirectly also Joe Polchinski and others.

    The existence of cosmic strings will be considered less likely after this observation, but of course, you are completely right that research of new physics in general and new physics of string theory in particular will continue, despite people like you who would prefer something else.

    I repeat that this is a disappointing news for everyone who feels uneasy about the lack of new experimental data that could direct our search in the last decades.

    Best wishes

  3. Lubos:

    What you called "entirely plausible possibility", I would call purely speculative ideas, in another word, crackpot ideas. That is not science. Purely speculate ideas that have no connection to experimental facts whatsoever is not science, but crackpots.

    You've got to be able to appreciate that the universe is a huge place full of galaxies of all shape and forms. CSL-1 is just a grain of sand from the ocean and it really doesn't prove anything either positive or negative. Crackpotists would continue to look for CSL-2 and CSL-3 and it is just a matter of luck that pretty soon they will find one or two incidences where two galaxies are so close to each other that even Hubble would not be able to tell them apart. Would you call that scientific proof? I won't.

    The universe is just so darn big that any strange thing you want you bet you can find out in there, with a little patience. If I were you I would wait until they have discovered a couple thousands such stuffs, before concluding that it is not just pure coincidence but contains some new physics.

    Mean while, the super string theory has already been proven to be wrong, for incorrectly predicted the existance of gravitons.

    Here is the gedanken experiment where gravitons spell trouble. Consider a blackhole. All it's mass is behind its event horizon and can not be observed by an outsider. However a blackhole still has gravity from all the mass inside. That means, if the gravity is mediated by gravitons. So some how the gravitons emitted by the mass inside the blackhole can still penetrate the event horizon and reach outside, that totally contradicts the notion that nothing, not even something at light speed, can escape the blackhole.

    What's worse. Since gravitons do escape from the interier of a blackhole, they can be used to carry information from the inside to the outside. For example some one unfortunately falling in could encode some Morse code, like "S.O.S.", using the gravitons, and send the message out, and the message would be detected by the LIGO.

  4. I mean it's true, if your proceeding to incorporate views on early universe formations, and wonder what did the universe look like before it became what it was.

    So one of these ideas is how from a certain background, what arises is given computer validations to perception and in these, I think of Andrey Kravstov's contributions are relevant here.

    Would I say then, that we should be aside his models?

  5. I would consider this good news for the theory, because there still are things to search for...

    In other words, if CSL-1 had somehow shown the correct structure of string theory to us immediately that would be a disaster! (==the disaster for the theoretical physisists) --> Once you correctly formulate the final TOE THEN there will be nothing left to search for...

    God luck with your searches!