[an error occurred while processing this directive]


Delve deeper into hot topics featured in NGM's August Geographica and Who Knew? with help from Resources. Click on a link, pick up a periodical, browse through a book, and explore!
The Book Guy
Grey TabMore Book Guy

Royal Maya City


The Multiverse
The universe as we know it just got more complicated

The universe is bigger than we think. This seems to be a cosmic truth. Times change, theories evolve, astronomers see new things in their telescopes—and the universe always turns out to be vaster and more mind-boggling than anyone suspected. The most dazzling new theory holds that our universe isn't just big, it's one of many. It's like a bubble in a huge vat of beer, and every other bubble is another universe. (We like this image for some reason.)

Our concept of the universe used to be tidier. Ancient Egyptians thought the sky was held up by mountains at the corners of the Earth, and the stars were not so far away. But in the 17th century the telescope shattered that notion. Through the lens, the stars were countless, and space had depth. Stars were suns, rendered faint only by great distance. Then, in 1923, Edwin Hubble proved that mysterious, wispy things called nebulae are actually galaxies, or "island universes," outside our own.

New telescopes have since revealed ever more galaxies, and we've grown accustomed to living in Carl Sagan's cosmos, with billions and billions of galaxies, each utterly lousy with stars. But Sagan may have been underestimating.

A satellite called the Wilkinson Microwave Anisotropy Probe recently captured a glimpse of the residual radiation from the young universe, when there were no galaxies, only perturbations in a seething, expanding cosmos. The data give a precise age to the universe: 13.7 billion years, plus or minus 200 million years. Perhaps more significantly, the data support the idea of cosmic inflation, a variant of the big bang. The inflationary theory states that very early in the expansion the cosmos suddenly inflated, becoming unimaginably vast in a fraction of a second.

If inflation is correct, the universe really is more than a million trillion trillion trillion times larger than the already enormous visible cosmos. It's practically infinite in scale. You have to speak like a child to convey the idea—it's basically a gazillion times larger than we thought. And there's more: One variation of the inflation theory suggests that our universe is a calm bubble, a kind of "no inflation zone" within an infinitely large, chaotic, eternally inflating "multiverse," and that this multiverse contains countless bubble universes, some of which almost surely contain intelligent observers trying to make sense of their own crazy cosmos.

The problem is, a multiverse is a hard theory to prove. "Is this science? Not yet," warns cosmologist Michael Turner of the University of Chicago. "We can't test it."

But here's the most alarming part about living in a multiverse. If the cosmos is more or less infinite in scale, then statistical probabilities dictate that somewhere there's a planet identical to Earth, containing creatures identical to us, leading identical lives. We don't buy it. Could there really be another world where Adam Sandler is a movie star?

—Joel Achenbach
    Washington Post staff writer

Web Links

Wilkinson Microwave Anisotropy Probe
Get background information and recent results from WMAP.

Inflation Theory
Review this tutorial on the inflation theory with links to other cosmological subjects.

More Articles By Joel Achenbach

Rough Draft
Writer Joel Achenbach's column is gaining a cult following. It takes a sometimes humorous, sometimes eye-squinting, but always intelligent look at today's headlines, personal interests, and the little life-annoyances we all live with.

A World Gone Mud
At this point of the monsoon season, everyone is acquainted with the substance generically known as mud. But is all mud the same?

At Bio 2003, The Latest Twist on DNA
The emphasis at the Biotechnology Industry Organization's 2003 convention was on industry, not science. This is the money side of the genomics revolution.

Free World Map

Guth, Alan.  The Inflationary Universe.  Helix Books, 1997.

Hogan, Craig.  The Little Book of the Big Bang. Springer-Verlag, 1998.

Rees, Martin.  Before the Beginning. Helix  Books, 1997.

Tegmark, Max.  "Parallel Universes." Scientific American, (May 2003, 40-51).


© 2003 National Geographic Society. All rights reserved. Privacy Policy       Advertising Opportunities       Masthead