Finding Life on other planets will take good science and luck

Humanity will have the tools to detect alien life in the next two decades, but whether scientists can actually find life in another solar system depends a lot on luck, a panel of experts said Wednesday (May 21).

While the James Webb Space Telescope (JWST), expected to launch in 2018, will have the ability to search for the chemical signatures of life in the atmospheres of alien worlds, it doesn't necessarily guarantee that scientists will find extraterrestrial life somewhere in the universe.

No one is sure how life begins or how ubiquitous it is, making it very difficult to pinpoint when and where to find it, scientists said during a session at the 30th US National Space Symposium in Clorado.

"We don't know how many planets we're going to have to examine before we find life, and not finding it on 10 or 100 doesn't mean it's not there," John Grunsfeld, NASA's associate administrator for the science mission directorate said during the panel. "This may be very tricky."

This diagram shows the position of Kepler-186f in relation to Earth.

Credit: NASA Ames/SETI Institute/JPL-CalTech

A mission still in the early stages of development could also help scientists investigate alien worlds even without the use of a large telescope.

"Starshade," the huge sunflower-shaped craft would block light from a star to allow a well-positioned space telescope to look at the atmospheres of rocky planets orbiting sun-like stars, a historically difficult feat.

By using the starshade, scientists can hunt for an "Earth twin" orbiting a yellow star in the habitable zone like Earth, the only planet scientists know hosts life.

"We'll have the capability to find it [life] and we'll have that capability within a decade with James Webb and hopefully within two decades with an Earth twin, but beyond that, it's really just up to chance," Seager, who is affiliated with the starshade group, said.

The project is led by Jeremy Kasdin, a professor at Princeton University, N.J., in conjunction with JPL and support from Northrop Grumman of Redondo Beach, Calif.

Kasdin gave a TED talk about the project on March 19.

Starshade: Space sunflower will help snap pictures of planets

The prototype Starshade, a giant structure designed to block the glare of stars so that future space telescopes can take pictures of planets.

A spacecraft that looks like a giant sunflower might one day be used to acquire images of Earth-like rocky planets around nearby stars.

The prototype deployable structure, called a starshade, is being developed by NASA's Jet Propulsion Laboratory in Pasadena, Calif.

The hunt is on for planets that resemble Earth in size, composition and temperature. Rocky planets with just the right temperature for liquid water—not too hot, not too cold—could be possible abodes for life outside our solar system.

NASA's Kepler mission has discovered hundreds of planets orbiting other stars, called exoplanets, some of which are a bit larger than Earth and lie in this comfortable "Goldilocks" zone.

Researchers generally think it's only a matter of time before we find perfect twins of Earth. The next step would be to image and characterise their spectra, or chemical signatures, which provide clear clues about whether those worlds could support life.

The Starshade is designed to help take those pictures of planets by blocking out the overwhelmingly bright light of their stars.

Simply put, the Starshade is analogous to holding your hand up to the sun to block it while taking a picture of somebody.

The proposed Starshade could launch together with a telescope. Once in space, it would separate from the rocket and telescope, unfurl its petals, then move into position to block the light of stars.