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Physicists describe grim end of the world

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January 15, 1997
Web posted at: 10:20 p.m. EST (0320 GMT)

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TORONTO (CNN) -- Scientists have been pondering for years how the universe will end, and now two University of Michigan astrophysicists have come up with a scenario that may make everyone breathe a little easier.

The good news is that the end is not near. The bad news is that when it does come, it's not going to be pretty.

The stars, the sun and the earth will die -- evaporating into radiation -- and there will be no light, only a vast soup of subatomic particles.

Greg Laughlin

"The fate of the earth is still in some sense not certain," astrophysicist Greg Laughlin says. "It's not clear if it will be destroyed by the sun or whether it will escape being destroyed when the sun turns into a red giant."

Laughlin and his University of Michigan colleague, Fred Adams, were in Toronto to describe their scenario at the winter meeting of the American Astronomical Society.

The universe as we know it, with stars and planets and life, is only temporary and is actually rather young, about 10 billion years old.

'We don't live in a preferred time'

nebula

"We don't live in a preferred time," Adams says. "Our current cosmological epoch has no central place in time." The here and now is but a brief phase, he says, in a sweep of time and change almost unfathomable to the human mind.

Using new information about the nature of the universe, they divided time into segments measured by what they call cosmological decades. Ten billion would be decade 10, or 10 multiplied by itself 10 times.

They call current time the Stelliferous, or star-filled era, a period that is about half over. At 20 billion to 30 billion years, the sun will expand into a red ball and die, overwhelming Earth with the heat. Oceans will boil and evaporate, and other planets near the sun also will burn, leaving nothing but orbiting chunks of barren rock.

At cosmological decade 15 (10 multiplied by itself 15 times), the Degenerate Era begins. Other stars will begin to die off as they burn up their nuclear fuel and the firmament as we know it ceases to shine.

"If you wait long enough," Adams says, "all of the stars in the universe will eventually run out of fuel and burn out."

An epoch of dead stars

The universe then enters a second stage, an epoch of degeneration.

graphic

"It's an era when most material is locked up in dead stars such as black holes, or white dwarfs," Laughlin says.

This era, 100 trillion trillion trillion years from now, marks the end of all planets. Protons, the subatomic particles at the center of the nuclei of atoms, will begin to decay. Without protons, matter evaporates into radiation. Carbon-based life is not possible, because carbon does not exist without protons.

"The proton decay epoch will initiate the most significant change in the universe," Adams says.

black hole

Cosmological decade 38 begins the black-hole era. Black holes feast on material sucked in from nearby and grow larger. This continues for about 60 cosmological decades.

And then, at cosmological decade 100, the dark era begins.

"Once the black holes have radiated away, the universe will consist of a diffuse sea of electrons, positrons, neutrinos and radiation," says Adams.

End of the world date: 1 plus 200 zeroes

And the universe is totally black.

"If you could transport yourself to the dark era, and look, the sky would be extremely dark," Laughlin says.

graphic

Adams and Laughlin say their study assumes that the universe will expand forever. To put a date on the end of the world in their scenario, take the year "one" and add 200 zeroes.

Other scientists believe the universe is closed, and that eventually it will contract in what some have called the "big crunch."

Either way, the end looks a little bleak. The good news is, it's a long, long way off.

 
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