As you may have heard NASA recently found seven rocky planets around a small red dwarf 39 light years away, or 2.293e14 miles away. To put that in perspective, the fastest object launched from Earth was Voyager 1 at 38,610 miles per hour or 3.22e8 miles per year. Doing a simple calculation tells us that it would take the first Voyager 711,105 years to reach TRAPPIST-1. So the answer to the popular question, “When can we get there?” is an unfortunate not anytime soon. However that doesn’t mean we can’t study and learn from this scientific discovery.
The discovery of the seven small planets come from observing planet transit events. When the planet passes in front of their star, the brightness of the star decreases and once the planet continues through its orbit the brightness increases. You can see this in the data from NASA below. Each colored node signifies a different planet whose orbit was observed crossing the star and the relative brightness that was lost when the planet was in transit.
TRAPPIST-1a is a cool red dwarf, 10 times cooler than our own sun, allowing the seven closely orbiting planets to still have temperatures that could sustain life (Temperature to the right plots mass vs. equilibrium temperature). The planets orbit extremely close, comparable to Jupiter’s Galilean moons (Pictured below). The combination of ultra-cool star and close orbits places three of these planets in the goldilocks zone, with the other planets being exceptionally close.
So what is next? How do scientist proceed forward with this discovery? The Kepler telescope will observe the system for 80 days to capture TRAPPIST-1h transit in front of the star a few more times. Once the James Webb Space Telescope (JWST) is launched next year, scientist will have the tools necessary to observe the rocky planets atmospheres. When the planet is in transit, the starlight will shine into the atmosphere, revealing the composition of the contents held from within. This process is called Transit Spectroscopy and we can use it to find the fundamental elements the planets atmospheres contains. The next step in this discovery will be the future observations and findings from JWST.
