February 23rd, 2017
In a significant breakthrough, National Aeronautics and Space Administration (NASA) scientists on Wednesday announced seven Earth-size planets orbiting a small star not too far away from our solar system. These planets could potentially harbour life, giving us the first opportunity to search for alien life outside our solar system.
The planets orbit a dwarf star named Trappist-1, which is about 40 light-years (235 trillion miles approx.) away from Earth. It is located in the constellation Aquarius. Three of the planets have been found in the “habitable zone”, where liquid water – and possibly life – might exist. The others are right on the doorstep of the solar system.
“This is the first time so many planets of this kind are found around the same star,” Michael Gillon, an astronomer at the University of Liege in Belgium and the leader of an international team that has been observing Trappist-1, said during a telephone news conference organized by the journal Nature, which published the findings on Wednesday.
Scientists will need to study the atmospheres of these planets before determining whether they could support some life or not.
Red dwarf stars are found in abundance, so astronomers are likely to find more planetary systems like that around Trappist-1 in the coming years.
Presently, the telescopes on the ground and the Hubble Space Telescope in orbit are trying to identify the molecules in the planetary atmospheres. The James Webb Space Telescope, which is scheduled to launch next year, will peer at the infrared wavelengths of light, ideal for studying Trappist-1.
Trappist-1 has been named after a robotic telescope in the Atacama Desert, Chile. The astronomers initially used the telescope to study the star, which astronomers call an “ultracool dwarf”, with only one-twelfth the mass of the sun and a surface temperature of 4,150 degrees Fahrenheit, much cooler than the 10,000 degrees radiating from the sun. “Trappist” is a short version of “Transiting Planets and Planetesimals Small Telescope”.
All the seven exoplanets (planets around a star other than the sun) are quite close to the dwarf star, circling it more quickly than the planets in our solar system circle our sun.
The closest completes an orbit in just 1.5 days. The farthest one completes an orbit in about 20 days. As these exoplanets are so close to a cool star, their surfaces could have the right temperatures to have water – one of the essential ingredients for life. This is a major breakthrough.