sible signatures of biological activity, such as carbon dioxide and ozone, or oxygen in combination with methane. Though not a biomarker in itself, water would also be required for a planet to support life — as least as it is known on Earth, notes Lisa Kaltenegger of Harvard-Smithsonian.

A mission capable of detecting these chemical fingerprints in a planet’s atmosphere wouldn’t be ready for launch for another decade. Such a mission might also manage to take a blurry picture of an Earthlike planet by using advanced techniques to blot out the blinding light from the parent star.

An exoplanet task force that included Boss and Lunine recently noted, however, that there could be a shortcut to looking for habitable exoplanets. Instead of looking for Earth-mass planets orbiting sunlike stars, scientists could focus on superEarths — planets five to 10 times as massive as Earth — orbiting light weight, cooler stars called M dwarfs. Because M dwarfs aren’t as hot as sunlike stars, the habitable zone lies relatively closer to these low-mass stars. That makes a habitable planet easier to detect. And it’s more likely that such a close-in planet will pass in front of its star as seen from Earth, allowing the starlight to filter through the distant planet’s atmosphere and reveal whether the composition might be compatible with life. The James Webb Space Telescope, scheduled for launch in 2013, could examine superEarths, determining which might be the best candidates for the search for extraterrestrial life.

Seeking strangeness

The universe has no dearth of oddball objects. But the JWST and a slew of other powerful telescopes now in the planning stages are likely to reveal even more exotic beasts that the cosmos has kept under wraps.

Astronomers have long known about neutron stars, the ultracompact cinders left behind by supernovas. These cin-

ders are so dense that they squeeze electrons and protons into giant balls of neutrons. And for more than two centuries researchers have theorized about black holes, which capture all matter and light that enter them.

But even stranger stuff may exist. For instance, particularly massive neutron stars may squeeze neutrons so tightly that they break down into quarks. By measuring the size and radius of neutron stars, researchers are attempting to find evidence for such “strange stars” or “quark stars.”

Another novel space oddity would be a wormhole — a black hole’s distant cousin. In 1935, Einstein and Nathan Rosen realized that general relativity allows such tunnels, which would directly connect two vastly distant regions of spacetime, or even locales in different universes.

Theorists once believed that these proposed portals could exist only for a fraction of a second. But calculations suggest that “exotic matter” — material endowed with a special property called negative energy — could prop a wormhole open much longer.

“There are mathematical solutions, but whether or not they correspond to something in reality remains to be seen,” says cosmologist Michael Turner of the University of Chicago.

Perhaps the strangest notion about the cosmos is that the observed universe is only one among many other universes, each residing in a pocket disconnected from the others.

Inflation — the early epoch of rapid expansion — could allow for an infinity of separate bubble universes. And string theory, which envisions each elementary particle as a string rather than a point, also suggests the existence of a vast ensemble of different universes, each with its own physical laws.

The notion of such a multiverse is the ultimate in the revolution begun by Copernicus nearly five centuries ago, Turner says. Not only is Earth not the center of the solar system or the galaxy, but our universe may be just one of many.

Four hundred years from now, says Turner, inflation may be remembered as the theory that drastically changed people’s vie w of the cosmos. “It may be infinitely bigger than we imagined,” he says. Much bigger than Galileo could have realized when he first peered at the sky through a crude set of magnifying lenses in 1609. s