Recent research suggests that some of the Earth-size planets orbiting the star TRAPPIST-1 could carry more water than our own planet. TRAPPIST-1 is an ultra-cool red dwarf discovered in 1999, and its planets were first documented within the past few years. Scientists have measured the density of TRAPPIST-1’s planets and concluded that the mass of some of these planets may be composed of five percent water – roughly 250 times the amount of water found in our planet’s oceans.
Stars such as TRAPPIST-1 are of particular interest to astronomers because their size and faintness allows for more in-depth study of orbiting planets. Through the European Union-funded SPECULOOS project, scientists have been able to focus on these planets as they search for life beyond Earth.
Researchers have also observed differences based on the planets’ distance from their sun. For example, planets closest to TRAPPIST-1 may contain thick, steamy atmospheres while outer planets may be covered in ice. Perhaps most importantly, astronomers have concluded that the lack of a hydrogen-rich atmosphere on three planets indicates that they are not gaseous and therefore much more likely candidates for harboring extraterrestrial life.
The intensive study of the TRAPPIST-1 system is only in its early stages. In 2020, NASA and the European Space Agency will launch the James Webb Space Telescope, which will be capable of detecting possible molecules of biological origin. “In the temperate – and potentially habitable – Earth-size regime, SPECULOOS’s detection potential should be significantly better,” Dr. Michaël Gillon from the University of Liège, Belgium told Science Magazine. “The next years are going to be very exciting!” Gillon plans on expanding the observation of Earth-like planets by searching through 1,000 stars similar to TRAPPIST-1.