March 25, 2010
Universe Still Expanding
The universe is still hurdling toward oblivion.
University of British Columbia astronomer Ludovic Van Waerbeke with an international team has confirmed that the expansion of the universe is accelerating after looking at data from the largest-ever survey conducted by the Hubble Space Telescope.
The astronomers studied more than 446,000 galaxies to map the matter distribution and the expansion history of the universe. This study enabled them to observe precisely how dark matter evolved in the universe and to reconstruct a three-dimensional map of the dark matter and use this to test Albert Einstein's theory of general relativity.
I find the idea of an accelerating universe depressing. Is the universe going to gradually spread out until each atom is by itself? Does the universe sort of end by diffusion where its various parts effectively become disconnected?
The researchers looked at 446 thousand galaxies. Imagine the number of stars in those galaxies.
A group of astronomers , led by Tim Schrabback of the Leiden Observatory, conducted an intensive study of over 446 000 galaxies within the COSMOS field, the result of the largest survey ever conducted with Hubble. In making the COSMOS survey, Hubble photographed 575 slightly overlapping views of the same part of the Universe using the Advanced Camera for Surveys (ACS) onboard Hubble. It took nearly 1000 hours of observations.
Just how many intelligent species have developed in these many galaxies? How many of those species got wiped out by supernovas, colliding stars, colliding galaxies, black holes, or quasars? What fraction of all the intelligent species that ever existed still exist today? How many are effectively unreachable?
Since the galaxies are accelerating away from each other, someday galaxy astronomers will only be able to study the local cluster of galaxies.
"I find the idea of an accelerating universe depressing."
Randall, back away from the computer. Go on outside for a while. It's spring and birds are singing. I don't think you need to worry about becoming a spreading cloud of your constituent atoms anytime soon.
"Does the universe sort of end by diffusion where its various parts effectively become disconnected?"
This is a likely eventuality. In "Cycles of Time", however, [Roger Penrose] moves far beyond this to develop a completely new perspective on cosmology ... to show how the expected ultimate fate of our accelerating, expanding universe can actually be reinterpreted as the 'Big Bang' of a new one.
There was a Woody Allen short film about a young boy who discovered with this telescope a new asteroid that in 2 billion years would undoubtedly destroy the Earth. After that moment, the short film follows the boy as he matures into manhood and to his final days. All he could do his whole life was obsess on the fact that in 2 billion years the Earth would meet its doom, all life destroyed. He was neurotic (what Woody film doesn't have such a character!?), he couldn't make meaningful relationships, etc.
I see this, Randall, because I share your depressing feeling regarding the expansion being stretched to atoms being strewn throughout space... I really do. And when I have such feeling, oddly enough, I think about that young boy with the telescope, and laugh a bit. And then, yeah, since it's spring, will try to go outside.
LAG has a good idea Randall.
My understanding of cosmology is limited to the popular non-scientific press. My understanding is that modern cosmology embodies theories that in some incomprehensibly distant era some catastrophe will occur that will make the universe unsuitable for life. That possibility, dubbed the "Big Rip" by Dennis Overbye is described in the following article:
February 17, 2004
From Space, a New View of Doomsday
By DENNIS OVERBYE
Once upon a time, if you wanted to talk about the end of the universe you had a choice, as Robert Frost put it, between fire and ice. Either the universe would collapse under its own weight one day, in a fiery "big crunch," or the galaxies, now flying outward from each other, would go on coasting outward forever, forever slowing, but never stopping while the cosmos grew darker and darker, colder and colder, as the stars gradually burned out like tired bulbs.
Now there is the Big Rip. Recent astronomical measurements, scientists say, cannot rule out the possibility that in a few billion years a mysterious force permeating space-time will be strong enough to blow everything apart, shred rocks, animals, molecules and finally even atoms in a last seemingly mad instant of cosmic self-abnegation. ... Instead of slowing down from cosmic gravity, as cosmologists had presumed for a century, the galaxies started speeding up about five billion years ago, like a driver hitting the gas pedal after passing a tollbooth. ...
... That number, known as w, is the ratio between the pressure and density of dark energy. Knowing this number and how it changes with time — if it does — might help scientists pick through different explanations of dark energy and thus the future of the universe — "whether it's gonna lead to a Big Rip, a Big Collapse or just a Big Fizzle," as Dr. Adam Riess of the Space Telescope Science Institute in Baltimore put it in an e-mail message.
This version of doomsday would start slowly. Then, billions of years from now, as phantom energy increased its push and the cosmic expansion accelerated, more and more galaxies would start to disappear from the sky as their speeds reached the speed of light. But things would not stop there.
Some billions of years from now, depending on the exact value of w, the phantom force from the phantom energy will be enough to overcome gravity and break up clusters of galaxies. That will happen about a billion years before the Big Rip itself.
After that the apocalypse speeds up. About 900 million years later, about 60 million years before the end, our own Milky Way galaxy will be torn apart. Three months before the rip, the solar system will fly apart. The Earth will explode when there is half an hour left on the cosmic clock.
The last item on Dr. Caldwell's doomsday agenda is the dissolution of atoms, 10^-19 , a tenth of a billionth of a billionth of a second before the Big Rip ends everything. "After the rip is like before the Big Bang," Dr. Caldwell said. "General relativity says: "The end. Time can't evolve."
The cosmos probably still has a lot of life in it, according to recent calculations by Dr. Krauss. Based on the current age of the universe, some 14 billion years, and other data, w cannot be less than about minus 1.2, he said, putting the Big Rip about 55 billion years in the future. ...
A demonstration that these ideas are not new to us:
Lift up your eyes to the heavens,
And look upon the earth beneath:
For the heavens shall vanish away like smoke,
And the earth shall wear out like a garment,
And its inhabitants shall die with them: but
My salvation shall be for ever, and
My righteousness will never fail.
Oh, When the sun refuse to shine.
Lord, I want to be in their number,
When the sun refuse to shine.
I can feel all my atoms expanding. I can.
Or perhaps it is the medication. They will be coming soon to give me more.
I think that, at our present state of knowledge, it makes as much sense to worry about "the big rip", as it did for earlier people to worry that the stars would wear out their paths on the crystal globe, and fall to earth crushing people. Let's give it a few billion years, and then reassess the prospects in light of further research...
Does it make any significant difference if the universe has been expanding for 13.75 billion years as science informs us or 5770 years as the Bible tells us?
Probably not; but I take some comfort in the universe being younger rather than older.
As my wife constantly reminds me: "I'm just a hopeless optimist."
Umm Martin, as a Christian myself, I wonder what some like yourself - who has little respect for science - is doing hanging out on a science blog?
(sorry - it had to be said)
I find your condescending and trite response rather boorish - the predictible argument of the anti-intellectual - what are you doing at a science blog when you could be out burying your head in the sand alongside Martin?
Just another reason we need to go ahead and implement an enlightened scientific world dictatorship now - as galactic engineering will require long term projects and research to accomplish - and the sooner we get to work on this the better the chances for the long term survival of our species.
(and we cannot sincerely have confidence that the Human Race will make it to even the next level of Civilization with our current kleptocratic, anachronistic, social hierarchies as they are presently)
I understand why people want to know the theoretical limits of life, even if they're far away. And, yet, at the end of the day, the sensible thing is to take Brett's point of view: these are still early days for our theoretical understanding of the universe, and our mental health will be better served by not taking limits too seriously that are billions of years away. All we can say is: these limits are possible, but more work is needed.
I've always liked Isaac Asimov's story about this question.
Yes, we need the ability to pursue long term goals. I do not think that'll become possible until genetic engineering for cognitive enhancement enables a much larger portion of the population to understand long term possibilities.
However, there's another possibility: escape to a parallel universe. If they exist and we can find a way to travel between them then the problem becomes how to search thru them to find ones that are at earlier stages of development or at least longer away from becoming dissipated.
Agreed - that certainly is an idea well worth pursuing!
(although it does open a whole new can of worms)
Born to oearly I think many of us were - perhaps we may yet live long enough to see the next renaissance period of man - it can not come frikkin' soon enough!
I'm against Universe expansion and have a blog over it:
For example a question: The universe expand in any radius at light speed: How can accelerate? At what speed expand the diameter (radius x 2)?
This and more questions, doubts, proofs and hypothesis agains Universe expansion in http://bigbangno.wordpress.com