New clues found relating to a recently-discovered set of planets shows they are the best place to find aliens outside our solar system, according to NASA.
Recent observations of the planets orbiting around what scientists have named Trappist-1 have shown more detailed information about what life could be like on the seven planets.
The discovery of the planets was made by scientists last year.
Scientists said the planets are made mostly of rock, like the Earth. About five per cent of their mass is made up of water, 250 times more than Earth.
The form that water takes on Trappist-1 planets would depend on how much heat they receive from their ultra-cool dwarf star, which is only about nine per cent as massive as our Sun.
Planets closest to the star are more likely to host water in the form of atmospheric vapor, while those farther away may have water frozen on their surfaces as ice. Trappist-1e is the rockiest planet of them all, but is still believed to have the potential to host some liquid water.
The space organisation’s Hubble Space Telescope has now surveyed six of the seven planets.
In a new study, Hubble revealed ‘at least three’ of the Trappist-1 planets, ‘d, e, and f’ do ‘not seem to contain puffy, hydrogen-rich atmospheres like the gas giants of our own solar system’.
Hydrogen is a greenhouse gas, and would make these close-in planets ‘hot and inhospitable to life’.
The question of the planets’ atmospheres is also important for understanding whether liquid water could be present on these surfaces — an essential ingredient for habitability.
In 2016, Hubble observations also did not find evidence for hydrogen atmospheres in c and d. These results and the new ones, instead, favor more compact atmospheres like those of Earth, Venus and Mars. Additional observations are needed to determine the hydrogen content of planet g’s atmosphere.
According to The Independent, Dr Amaury Triaud, from the University of Birmingham said:
Of the seven planets, and of all the exoplanets that have been identified so far, Trappist-1e is the most resembling Earth, when we consider the amount of energy a planet receives from its star, and its density, which reflects its internal composition.
As our next step we would like to find out whether the planet has an atmosphere, since our only method to detect presence of biology beyond the solar system relies on studying the chemistry of an exoplanet’s atmosphere.
The Trappist-1 discovery was made by NASA’s Kepler space telescope, which was built to discover other planets similar to Earth and which could potentially sustain life.
It completed its main mission back in 2012, however the Kepler telescope is still collecting data – in 2014 it began a new mission, dubbed ‘K2’, to search for more exoplanets and analyse other cosmic mysteries.
Due to the sheer amount of data being transmitted through the telescope scientists on the ground are having trouble keeping up, which is why they’ve introduced Google’s AI program to help with the task at hand.
At the time, NASA said three of the seven planets were the ‘holy grail for planet-hunting astronomers’ as they sit within a climate which could, theoretically, allow for alien life to grow.