Somewhere out there are 200,000 stars that are about to get their picture taken. Much more important, there are who-knows-how-many planets circling those stars, and there’s at least a chance that there will be organisms on some of them that could smile for the camera. That’s the hope, at least. And NASA’s Transiting Exoplanet Survey Satellite (TESS), which is set for launch Monday at 6:32 PM EDT from Cape Canaveral, is about to try to make it a reality.
Planet-hunting is a relatively new field for astronomers. Until very recently, we knew of no other stars in the universe other than our own sun that are circled by planets. It was in 1992 that the first two exoplanets were discovered orbiting a pulsar—a rapidly rotating neutron star—2,300 light years from Earth. In 1995, the first exoplanet orbiting a sun-like star was discovered. But it was not until the Kepler Space Telescope was launched in 2009 that the exoplanet population exploded. In the nine years that the now-aging Kepler has been aloft, it has detected 2,343 confirmed exoplanets, as well as another 2,244 candidate planets that need further study.
Kepler was designed to do its work in the most boring way possible: by staring unblinking at a single ten-degree by ten-degree square in the 360-degree bowl of the sky, looking for the tiny dimming of light that occurs when an orbiting planet passes in front of its star. That single observation can reveal both the diameter of the planet and its orbital period, or how fast it makes a single revolution. That, in turn, can tell you something about whether it’s Earth-like, and thus potentially habitable.
The problem is that Kepler’s narrow but deep look into the cosmos turned up a lot of extremely far-off exoplanets thousands of light years …read more
Source:: Time – Science