Posted on 03/02/2005 10:11:19 AM PST by Michael Barnes
Could two lookalike galaxies, barely a whisker apart in the night sky, herald a revolution in our understanding of fundamental physics? Some physicists believe that the two galaxies are the same - its image has been split into two, they maintain, by a "cosmic string"; a San Andreas Fault in the very fabric of space and time.
If this interpretation is correct, then CSL-1 - the name of the curious double galaxy - is the first concrete evidence for "superstring theory": the best candidate for a "theory of everything", which attempts to encapsulate all the phenomena of nature in one neat set of equations.
Superstring theory views the fundamental building blocks of all matter - the electrons and quarks that make up the atoms in our bodies - as ultra- tiny pieces of vibrating "string". And, just as different vibrations of a violin string correspond to different musical notes, different vibrations of this fundamental string correspond to different fundamental particles.
The problem with string theory is that the strings are fantastically smaller than atoms and, therefore, impossible to detect in any conceivable laboratory experiment. But recently, physicists realised that the extreme conditions that existed in the early universe could have spawned enormously big strings. It is one of these "cosmic superstrings" that some believe is passing between the Earth and CSL- 1, and, in the process, creating the curious double image of the galaxy.
The realisation that big strings are possible has come from exploring the most esoteric implications of the theory. For instance, the only way strings can vibrate in enough different ways to mimic all the known fundamental particles is if the strings vibrate in a space-time of 10 dimensions.
Since we appear to live in a universe with a mere four dimensions - three of space and one of time - string theorists have been forced to postulate the existence of six extra space dimensions "rolled up" so small we have overlooked them.
The existence of the extra dimensions opens up the possibility of more complex objects. In addition to strings, which extend in only one dimension, it is possible to have objects with two, three or more dimensions. These are dubbed branes, or p-branes, where the "p" denotes the number of their dimensions.
This has raised the possibility that our universe is a three- brane - a three- dimensional "island", adrift in a 10-dimensional space. And, if it is, it may not be alone. Some have suggested that the big bang was caused when another brane collided with our own 13.7 billion years ago (See "Highly strung", The Independent, 7 July 2004).
Crucially, a collision between branes creates strings - both within each brane and as a kind of spaghetti connecting the branes. And these can be stretched to cosmic dimensions to make cosmic superstrings. "Cosmic strings turn out to be pretty much inevitable in the brane scenario," says Tom Kibble of Imperial College in London.
Cosmic superstrings would be under enormous tension, like a geological fault in the Earth's crust. But, being free to move, they would attempt to relieve the tension by lashing about through space at almost the speed of light. But their most interesting property is the effect they have on their surroundings. "A string distorts the space around it in a very distinctive way," says Kibble.
One way to visualise this is to imagine a string coming up through this page. Imagine cutting from the paper a narrow triangle whose tip is at the string, then gluing the paper back together again. The result will be a shallow cone centred on the string.
Because of this distortion of space, if a string passes between us and a distant galaxy - a giant collection of stars like our Milky Way - the light of the galaxy can come to Earth along two possible routes: one on either side of the string. Consequently, there will be two identical images of the galaxy only a whisker apart - which is exactly what is seen in the case of CSL-1.
CSL-1 was discovered by a team led by Mikhail Sazhin of Capodimonte Astronomical Observatory in Naples and the Sternberg Astronomical Institute in Moscow. They christened it Capodimonte- Sternberg Lens Candidate 1, which is where the CSL-1 comes from. "It looks like the signature of a string to me," says Kibble. "However, it is always possible we are seeing two galaxies that just happen to look surprisingly similar." This is the view of the sceptics. "CSL- 1 is most likely just a pair of galaxies that happened to be close together on the sky," says Abraham Loeb of the Harvard-Smithsonian Centre for Astrophysics. "We know of many close pairs of galaxies in the local universe, including our own Milky Way and Andromeda." But others are keeping their fingers crossed that Loeb is wrong. "I am hoping nature won't have played such a trick on us," says Tanmay Vachaspati of Case Western Reserve University in Ohio.
If CSL-1 was the only piece of evidence for a cosmic superstring it might be easy to brush it under the carpet. But it isn't. There is the "double quasar" Q0957+561A,B. Discovered at Jodrell Bank near Manchester in 1979, the two images of a super-bright galaxy, or quasar, are formed by a galaxy lying between the quasar and the Earth.
The gravity of the intervening galaxy bends the light of the quasar so that it follows two distinct paths to Earth, creating two images of unequal brightness. Crucially, the two light paths are of different lengths and so the light takes a different time to travel along each. In fact, astronomers find that when one image brightens, the other image brightens 417.1 days later.
But this is not what has been found by a team of astronomers from the US and the Ukraine, led by Rudolph Schild of the Harvard- Smithsonian Centre for Astrophysics. When they studied the two images, they noticed that, between September 1994 and July 1995, the two images brightened and faded at the same time - with no time delay The two images did this four times, on each occasion for a period of about 100 days.
The only way Schild and his colleagues can make sense of this behaviour is if, between September 1994 and July 1995, something moved across our line of sight to the quasar, simultaneously affecting the light coming down both paths to the Earth. The only thing that fits the bill, they claim, is a vibrating loop of cosmic string moving across the line of sight at about 70 per cent of the speed of light.
To oscillate once every 100 days or so, the loop has to be very small - no bigger than 1 per cent of the distance between the Sun and the nearest star. And Schild and his colleagues calculate that the string must be remarkably close to us - well within our Milky Way galaxy.
Most physicists remain sceptical about the evidence for cosmic superstrings. If the case is to be strengthened, it will be necessary to find more candidates like CSL-1 and Q0957+561A,B. Alternatively, it will be necessary to detect the "gravitational waves" coming from a string. These are ripples in the fabric of space, much like the ripples which spread out on a pond from an impacting raindrop.
Strings are travelling very fast. If they get a kink in them, it is possible for this part of the string to crack like a whip. The part producing the crack travels at almost the speed of light and should produce an intense burst of gravitational waves. As first pointed out by Thibault Damour of the Institut des Hautes etudes Scientifiques in Paris and Alex Vilenkin of Tufts Institute of Cosmology in the US, such signals could be detected in the next few years by Europe's Virgo detector or America's Laser Interferometric Gravitational-Wave Observatory.
String theory has long been criticised as that which makes no observable predictions about the universe we live in. If the discovery of cosmic superstrings holds up, the theory may finally have connected with reality and the critics may at last be silenced.
Marcus Chown is the author of `The Universe Next Door' (Headline)
Makes sense. I'm an agnostic and am forever bored by non-believers who pretend to have all the answers. A sour bunch.
Not me. Nothing beats the original radio series.
Hawkins understood at that moment that cosmology had actually been certifying as correct the Catholic Church's understanding of the nature of the universe. From that time on, he has been maniacal in his attempts to undermine the theories he had presented to the Pope, with preposterous results that have been proved wrong at every opportunity to observe excpected consequences.
Odd; I've read "A Brief History of Time," and don't recall anything like that in it. Perhaps you could provide a citation or link to substantiate your claim.
In the meanwhile, the readers may find this quote from the text of interest, as it indicates quite the opposite of what you have claimed.
Throughout the 1970s I had been mainly studying black holes, but in 1981 my interest in questions about the origin and fate of the universe was reawakened when I attended a conference on cosmology organized by the Jesuits in the Vatican. The Catholic Church had made a bad mistake with Galileo when it tried to lay down the law on a question of science, declaring that the sun went around the earth. Now, centuries later, it had decided to invite a number of experts to advise it on cosmology. At the end of the conference the participants were granted an audience with the Pope. He told us that is was all right to study the evolution of the universe after the big bang, but we should not inquire into the big bang itself because that was the moment of Creation and therefore the work of God. I was glad then that he did not know the subject of the talk I had just given at the conference--the possibility that space-time was finite but had no boundary, which means that it had no beginning, no moment of Creation. I had no desire to share the fate of Galileo, with whom I feel a strong sense of identity, partly because of the coincidence of having been born exactly 300 years after his death!
What do you get when you multiply six by nine.
In base 13.
It's a Disney animation, for crying out loud. I did read a very long interview with the screenwriter, and he seemed OK. He said everyone else turned it down for fear of being remembered forever as the one who screwed up the Hitchhiker.
I think the script will be OK, but I fear for the animation. Marvin looks like a gumball machine. But maybe that's the way it should be.
It's possible I have mixed up my Hawking's sources; I no longer have the book (I took it out of the library about a decade ago), so it'll take me a little while to look it up. But it was one of those brief passages I snagged with an "A-ha!"... Not a highlighted turning point from Hawkings' perspective. Perhaps you did read it, but not attaching the same significance to it, you quickly forgot about it?
Who is the source of the quote you provide?
The Church did indeed make an error with Galileo. They went too far, extending Galileo's apostasy into an ad-hominem on all his assertions. But the author's characterizations about the constraints placed on him purport the church to be making an uncharacteristically illogical demand: Why would the Church permit the study of the period following the Big Bang, but put the Big Bang itself off limits? Or maybe what he means to state is that the Church didn't want the symposium to delve into WHY the big bang happened, as many physicists' recent exploration of that (especially Hawkings') tends to be more metaphysics than physics (e.g., Hawkings' infinite numbers of universes in infinite dimensions.)
>>>>Now, what was the question again?<<<<
>>What do you get when you multiply six by nine...In base 13.<<
>>>>What do you get when you multiply nine by five (post 13)<<<<
Doh!
Just so long as the gumballs have big, goofy grins anf wavy arms.
yeah my kids know it all already too
I'd settle for figuring out what you think you said.
I just played fast and loose with the deepest mysteries of physics AND Catholicism according to my cursory understandings and you expect to figure out what I wrote? Naaah. What's scary is there's a couple people who seem to have understood me!
she's 14, right?
To make sure I'm not misunderstood: What I wrote in Paragraph 1 of my post 25 is a synopsis of what Hawking himself wrote. What I wrote after ("From that time on...") is my characterization of what happened next.
[Sigh ...]
No, no, no.
The question Deep Thought provided the answer to (42) is
"What is 6 times 9?"
And it works (potential spoiler):
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it works in base 13. Now, what does THAT imply?
I had forgotten that part....Gonna have to re-read the books...classics they are.
the base 13 stuff is not in the books, though if you do the math it works.
In the old LP record made from the BBC radio scripts (and supposedly in the radio show, as well) someone says in the background "base 13" when Arthur pulls out the "what is 6 times 9" from the bag.
I first got introduced to the BBC TV series, which was 9 half hour episodes made from squishing the first half of the original Hitchhikers Guide To The Galaxy book with the majority of Resteraunt At The End Of The Universe. My wife and I then read the books that were out then, up through "So Long And Thanks For All The Fish," while driving regularly from the Pocono's to NY for doctors visits (she'd read them aloud while I drove).
It's a rare thing to have trouble driving because you're laughing so much from what someone is reading to you.
That would be Hawking, from "A Brief History of Time"....
String Theory jives well my my Theroy of "Infinate Simultaneous Multi-Dimentional Universe and the use of the 'subconcious' to navigate it"
Power of positive will, higher level brain function, deja-vu, the "6th sense", etc...
It is true.
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