On Feb 22, 2017, NASA released the discovery of seven planets with the potential for water on their surfaces. NASA has been charting these types of planets for a long time; in fact, over 3,000 exoplanets have been recorded to date. So what makes this exoplanet discovery so wild? All seven planets orbit the same star called TRAPPIST-1, and are positioned pretty close together. Three of these seven are located in what is known as the “habitable zone” or the “goldilocks zone”. This means that the planets orbit their their star at a distance where water remains liquid i.e. doesn’t boil off because the star’s rays are too hot and close, or freeze because the star is so far away. TRAPPIST-1 is an M dwarf star, which means it is relatively cool and small when compared to other stars- even our Sun. TRAPPIST-1 is also considered nearby: it is only about 40 lightyears away.
How did NASA discover this group of exoplanets? The Spitzer Space Telescope. Spitzer looks at the brightness of stars, and as planets pass in front of them, allows us to see that light is being blocked by the planet. The amount of light blocked relates to the size of the planet, and the time it takes for the planet to pass over the star again tells us the orbital period. The orbital periods of the planets tell us the distance the planet is from the star as well, which is how scientists can determine whether the planet is in the habitable zone or not.
To use an interactive diagram to see what it could be like to “planet hop” around this solar system, or to view a 360 degree interpretation of one of the exoplanet’s surfaces, you can follow these cool links:
To watch the news release sent out by NASA follow this link: (Around minute 6:40 is when one of the scientists explains how NASA made this discovery using Spitzer) http://www.ustream.tv/recorded/100200725