Distant future bears bad news for runaway universe

Aug. 10, 2001

Distant future bears bad news for runaway universe



We live in a universe that is expanding away from us, so that eventually all objects outside our own galaxy will be invisible. But, according to Professor Lawrence Krauss, this won’t occur for trillions of years, so there’s no need to worry just yet.

“I’ve tried to argue that the longer we wait, the less we’ll see, so we should fund cosmology now,” Krauss joked. “But the Washington bureaucracy moves even slower than the expanding universe.”

Krauss spoke at the Lab as a part of the Director’s Distinguished Lecturer series. His talk, “Life, The Universe, and Nothing,” explored several theories about the shape of the universe and its imminent demise. Krauss also opened his talk with a tribute to Ernest O. Lawrence, the founder and namesake of the Lawrence Livermore National Laboratory, in honor of the 100th anniversary of Lawrence’s birth.

“Lawrence was a man who captured the public’s imagination,” Krauss said of the Nobel Prize-winning scientist. “His was the idea that every time we open a new window on the universe, we’re surprised by what we find. The idea that science can capture the public’s imagination is a notion I’d like to carry on.”

Krauss, the chair of the Physics Department at Case Western Reserve University, has written numerous books on the early universe and cosmology.
“All the physics points to the fact that we live in a universe that is flat,” Krauss continued. “But we’re trying to find a way to prove that we live in a curved universe.” He noted that what people see when they look at stars is actually the way the star looked 10 billion years ago, as the image has taken that long to reach Earth.

“So in theory, we could look far enough out into space and we’d see the Big Bang,” Krauss said. “But we can’t see that far, because there’s basically a wall of plasma breakdown in the way.” This “wall” of plasma, coupled with satellite imagery, has led scientists to believe that the universe is, indeed, flat. But as Krauss pointed out, “there’s not enough matter in the universe to make the world flat.”

“Where does that matter come from?” Krauss asked. “We look to exploding stars. When a star explodes, it is as bright as the entire galaxy momentarily.”
Krauss also said that astronomers and cosmologists previously believed the universe to be slowing down, or collapsing in on itself.

“But it seems now that the universe is actually speeding up,” he said. “The only way there can be enough ‘empty space’ for all the star matter is if the universe is pulling apart.”

The implication of these theories is, according to Krauss, a miserable future.

“In time, all objects outside our local supercluster of galaxies will become invisible – as the universe expands exponentially, they will literally be pulled too far away to see,” Krauss said.

Krauss ended his talk by stating that cosmologists cannot be sure what the distant future holds for the universe.

“We need infinite time to determine the ultimate fate of the universe, but we have only a finite time left,” he
concluded.