On Wednesday afternoon, NASA announced the discovery of 7 Earth-sized rocky planets orbiting around a dwarf star known as TRAPPIST-1. Originally, only 2 planets had been found in 2016 so this is indeed quite the step up. The internet has been bombarded with excitement over this discovery but what does it all mean? Let’s look at everything we know.
The mini solar system located in the Aquarius constellation is comprised of a cool dwarf sun called TRAPPIST-1 that is approximately the size of Jupiter; the largest planet in our solar system when disregarding the rings of Saturn. The solar system is so small that from the surface of one of the planets, you’d be able to see a handful of the others racing through the sky because of their short orbital periods (time taken to orbit an object once). TRAPPIST-1 is named after the telescope used to find it in Chile an acronym for the TRAnsiting Planets and PlanetesImals Small Telescope. The solar system currently sits approximately 39 light years away or 369 trillion km (229 trillion miles) away, which is some distance. The current space speed record belongs to the Juno spacecraft that has clocked a top speed of 265,000km/h (165,000 mph). Even if a spacecraft was able to accelerate to these speeds spontaneously and deccelerate at the same rate, it would take approximately 158,847 years to reach the solar system. Though we still have a way to go, in relation to other systems this is very close.
Of the 7 planets orbiting the dwarf, 3 of them (TRAPPIST-1e, 1f and 1g) sit within the system’s ‘habitable zone’. This is the distance away from a star in which the planet’s environment allows for water to exist in a liquid state. Think of Goldilocks; you’re too close to the sun and water vaporizes, too far and it freezes. It needs to be just right. So far, it is predicted that 1f is the most likely to have liquid water present. Even though we think there is water present, it is just a prediction. NASA’s James Webb telescope could hopefully teach us more about the system with its launch aimed for 2018. It will detect the chemical markers of methane, oxygen and water within the planet’s possible atmosphere using light in a process called spectrometry. In this example, spectrometers spread out light bounced off of distant planets separating it into it’s different wavelengths or ‘spectra’. What’s cool about elements is that their presences absorbs certain wavelengths of light. This can allow for the creation of absorption spectrums. If a specific wavelength of light is missing then we know that a specific element is present (image below for more). It is these readings that will be used to further assess if the planets are habitable or not. This assessment allows for scientists to reinforce their hypotheses on the existence of life or chances of a new home.
One of the issues associated with this system is that the planets might be tidally locked to the star; meaning the same side is always facing the sun. Similar to how one side of the moon is always facing the Earth. Due to this, one side is always daytime and the other night time. This leads to fluctuations in the temperature of different area’s as well as unforeseeable variations in the climate system. Regardless, the only way we’re really going to get there quickly is by using the system proposed by Stephen Hawkings. Project ‘Breakthrough Starshot’ was announced last year and was a project looking into nano-sized spacecraft that would use lasers and solar sails. These lasers would hypothetically allow for the crafts to reach speeds 20% that of the speed of light (≈215,850,569km/h). Not including how long it would take to accelerate or decelerate to these speeds, it would take approximately 187 years to reach TRAPPIST-1. This, however, is still a long way off with many issues associated with space travel.
Naming of the systems planets will be left up to the International Astronomical Union (IAU); a coalition of approximately 10,000 international scientist from over 96 countries. Regardless of the names that are bestowed upon them, this is an exciting time with the chances of alien life being discovered in the solar system next door within a decade!