Other Earth exoplanet hunter - Starshade

The ‘Other Earth’? A Look At The Exoplanet Hunt Beyond Our Solar System

Is the “other Earth” among the thousands of exoplanets that have already been discovered outside our solar system? New technology being developed by NASA aims to find that out.

The search for other Earths — planets like our own Earth that would feature atmospheric conditions that could allow for the development of life — has long been a dream of many scientists among others through the decades.

MIT astrophysicist Sara Seager is one of them, as she told CNN earlier this month, “I want to find another Earth. That’s what I’m living for.”

Seager is part of NASA’s TESS, or Transiting Exoplanet Survey Satellite, project, a two-year space mission set to launch in 2017. It will collect and relay data to the James Webb Space Telescope, which is scheduled to launch in 2018. It’s just one of several projects currently in various stages of development, all with the end goal of finding that elusive other Earth.

On Thursday, NASA announced developments related to new technologies that will help them find the elusive earth-like planets beyond the solar system. NASA’s Exoplanet Exploration Program Office is located at the agency’s Jet Propulsion Laboratory in Pasadena, California, and Gary Blackwood is the manager of the Exoplanet Exploration Program.

“It’s an exciting time for exoplanet research. This is history in the making.”

Some of the new technology, described in a NASA media release, will look for exoplanets similar to Earth by looking for clues of to atmosphere and climates. The next generation of instrumentation will use data about the light emitted by the exoplanet to produce a chemical analysis or spectra. The light is split into all the different colors it contains, and their relative concentrations provide information about the conditions on the exoplanet’s surface and whether or not they might be habitable in the same way as our Earth.

Telescopes on Earth can only view so far, in part because of the blurring effect of Earth’s atmosphere. New space missions will use telescopes mounted on spacecraft that observe and relay data from out in space. One of the several proposed space missions that are developing coronagraph technology is the WFIRST, or Wide-Field Infrared Survey Telescope, mission at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

Exoplanets can’t be viewed through a conventional telescope. In fact, the first exoplanets were discovered not by imaging technology but by observing the effects of their gravitational pull on surrounding objects. The other Earth orbits a star just as our Earth orbits the sun, and the brilliant light emanating from that star would obliterate any light coming from the exoplanet itself. As a point of reference, our own sun is about 10 billion times brighter than the light produced by planet Earth.

Most of the exoplanets discovered so far seem to consist largely of gas. The reason for that is that such planets, like Jupiter in our own solar system, are relatively brighter and easier to see and orbit farther from their own respective suns. Dimmer and rocky in composition, other Earth is likely to be found closer to the blinding light of its sun.

Coronagraph technology has been developed to counteract that effect. It was adopted in the early 20th century as a way of studying the corona surrounding our own sun without being blinded by its radiance. Naturally, today’s version is much more sophisticated. As coronagraph technology develops, it will enable researchers to view smaller and dimmers exoplanets.

Most coronagraph technology is designed to fit inside telescopes while others are more ambitious. Nick Siegler, the program chief technologist for the Exoplanet Exploration Program Office, explains the differences between those models and the starshade, a proposed project described as a “giant flower-shaped spacecraft” in a NASA media release.

“Starshades, on the other hand, are separate spacecraft that fly in front of other telescopes, so they are more like driving behind a big truck in front of you to block the light of the sun.”

The first exoplanets were discovered in the 1990s. Since then, more than 6,000 exoplanets have been discovered inhabiting space outside our solar system. The first other Earth, a planet with a size similar to our Earth in an area where liquid water could exist, was discovered by NASA in 2014.

[Image via NASA/JPL-Caltech]

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