Posted on 03/12/2002 12:01:15 PM PST by RightWhale
Universe Frozen in Time
by Liesbeth de Bakker of our Science Unit, 12 March 2002
You'd better take a good look while you can, because the Universe is going to disappear! As space ages and expands, fewer and fewer galaxies will be visible to us. Even weirder, as we watch these galaxies fade, their appearance will freeze in time. No matter how long we watch , like celluloid heroes in the cinema they will never grow older or change. They will only grow dimmer as they recede from us.
For decades the fate of the Universe was a favourite topic of study for many a distinguished astronomer. There were two main lines of thought. Either the universe would keep on expanding, as it had done for 14 billion years since its ‘Big Bang' birth, or one day gravity would pull all stars and galaxies back together again in a life-ending crunch. It's only recently that consensus was reached thanks to new technology and data: Universal expansion will go on with ever increasing speed.
Bathroom Brilliance
Inspired by these revelations, Avi Loeb - a professor of astronomy at Harvard University in the USA - was thinking about the consequences one morning in his bathroom. "What will people see, looking at the sky billions of years from now?", he wondered. "So I went into my office and did some calculations. They took a day or two but I came up with some very interesting results."
Arrested Development
"50 to 100 billion years from now the universe will be a dark and lonely place," surmises Avi Loeb. We can only see a star if its light can reach us here on Earth. But if the universe is expanding at an ever increasing speed, then one day distant galaxies will be travelling away from us faster than the speed of light - a rare exception to the rule that nothing can go faster than light. When this happens, the light emitted by such galaxies will no longer be able to reach the Earth. "We will see how a star or galaxy develops up to that point," explains Professor Loeb, "and afterwards the source of light will be frozen in time."
Outlook for Astronomy
This has implications for our study of the distant Universe because the amount of information available to us is finite. So not only will the number of visible galaxies gradually shrink, we will also be unable to watch their evolution later in their history. Therefore Prof. Loeb thinks that astronomers should concentrate on the outer reaches of the universe now, rather than focus on what's relatively nearby . "The further away the source, the quicker it'll be gone," he says. "As a matter of fact, if we sent out a signal now, it would not be able to reach some sources that are already outside our reach. So if there are extraterrestrial communities out there, some of them will already be out of contact with us."
Promising Future
Isn't it silly though, to worry about a Universe that will be ‘frozen' in 50 billion years' time, when our own Sun will die much sooner, possibly taking the human race with it? Avi Loeb isn't fazed by such facts. "By that time", he muses, "newer stars will dominate our galaxy. We could venture out and find a new world. Our science is still young. Look at what we have achieved in just 100 years. If we can protect ourselves against destructive forces within our society, I can imagine us doing lots of very unusual things."
Only 50 billion years left!
uh, okay
That assumes that they are moving away from us at the speed of light (or close to it). We may see what happened millions of years ago ... but it won't be frozen. Who knows how many stars we see today, have actually exploded millions or thousands of years ago, it's just that the light of their demise hasn't reached us yet.
However, it is nice to realize that some galaxies are already beyond the event horizon. I'm hoping those are the ones containing the man-eaters.
They'll see 3D holographic sky-projected news flashes about the latest attempts at a Middle East peace plan.
Some may find themselves teaching political astronomy at Harvard.
Some will. Some will even know how to make good spear points.
Chemtrails.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.