for National Geographic News
Travel forward in time a hundred billion years, and you'll land in a universe that has stopped expanding—a vast, empty space at a standstill.
Or at least it will appear that way, according to a prize-winning essay in a 2007 contest by the nonprofit Gravity Research Foundation.
The essay, by Lawrence Krauss of Case Western Reserve University and Robert J. Scherrer of Vanderbilt University, will be published in the October issue of the Journal of Relativity and Gravitation.
In the far-flung future, Earth will most likely be a distant memory—the entire planet will probably be destroyed when the sun expands into its red giant phase in about ten billion years.
But if new life-forms come to occupy Earth's real estate, all evidence of other galaxies—and thus an expanding universe—will have disappeared from their view.
"Observers will be able to infer a finite age for their island universe," the essay authors write. "But beyond that, cosmology"—the study of the origin and nature of the universe—"will effectively be over."
Back to Basics
Instead, future models of the universe will look like a throwback to the 19th century, when astronomers believed that the Milky Way was the only galaxy.
"In some sense it's poetic," Krauss said. "The future universe will look much like what people first thought it did when they first started thinking about cosmology."
At that time the very notion that other galaxies could exist was a subject of heated debate and a fair amount of animosity among experts.
Conservatives thought that clusters of stars they called nebulae were clouds of gas within our galaxy where new stars were likely to form.
But Vesto Melvin Slipher at Lowell Observatory in Flagstaff, Arizona, was the first to use a phenomenon called redshift to prove otherwise.
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