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NASA held a press conference today announcing further discoveries in the field of exoplanets (planet in orbit around other stars). In the conference, NASA provided details of an exoplanet system located around a relatively close star. The star, Trappist-1, is an ultra-cool red dwarf, much smaller than our Sun and located 39 light years from Earth. The star plays host to a remarkable planetary system.

NASA has discovered seven planets in orbit around the star. All of them are rocky or earthlike planets and three of these planets are found in the habitable or Goldilocks zone. The habitable or Goldilocks zone is the region around a star where the temperature is just right to allow liquid water to exist. These three planets are all earth-size rocky worlds and the scientists have announced that one of them is likely to have a water-rich composition. What is remarkable about this discovery is that the star plays hosts to so many rocky worlds, and that so many of these worlds are earth like or rocky, and also that three of the worlds might have liquid water on their surface.

That NASA was able to discover these worlds at all is testament to the speed at which the science in this discipline is advancing. Next year will see the launch of the James Webb Space Telescope. This telescope will carry instruments on board that will allow us to probe the atmospheres of these planets, if they have atmospheres, and ascertain what they are made of. Scientists will be looking for oxygen, ozone, methane and other gasses that serve as biosignatures hinting at the presence of life on other worlds.

For the moment, we can just speculate on what the planets may hold. So, what about going out tonight and having a look. Trappist-1 is located in the constellation of Aquarius, but unfortunately the star is much smaller than the Sun and consequently much dimmer. It is impossible to see without a really large telescope.

For all those thinking of little green men, the scientists who look for extraterrestrial life (SETI) have already pointed their radio telescopes at the system, but have found nothing. Even if we sent a signal to the planets, we would have to wait almost 80 years for any response!
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This illustration shows the possible surface of TRAPPIST-1f, one of the newly discovered planets in the TRAPPIST-1 system. Scientists using the Spitzer Space Telescope and ground-based telescopes have discovered that there are seven Earth-size planets in the system.
PICTURE: NASA/JPL-CALTECH