Astronomers Discover Earth-Sized Planets Around Nearby Star
NASA has discovered seven rocky planets about the size of the earth revolving around a star in our Milky Way. The planets belong to a dwarf star named Trappist-1, which is about 40 light years away from earth. Astronomers have become excited by the discovery , feeling that the planets may have conditions needed to support life.
It is the first time that a solar system like ours has been discovered with so many planets revolving around it. The planets are so close to their star that it only takes them between 1 and 20 days to move around it. In contrast, our sun’s closest planet, Mercury, needs 88 days to move around it once. Scientists also believe that, like our moon, the same side of the planets always face the star.
Trappist-1 is a small star that is thousands of times less brighter than our sun. It burns hydrogen so slowly that it will exist for trillions of years. Even though the planets get much less light than we do , three of them are near enough to make them temperate. Water could be found on their surfaces, but scientists do not know anything about their atmospheres.
Because the Trappist-1 system is so close to us, NASA is looking forward to getting new information when the powerful new James Webb Space Telescope is launched next year.
The first planets outside our solar system were discovered in the 1990s. Since then about 3500 exoplanets have been found.
- astronomer = person who studies the stars and the planets
- atmosphere = the mixture of gases that is around a planet
- condition = the state that something is in
- discover = to find something for the first time
- dwarf star = a small star that is not very bright
- even though = while
- exist = to be around
- hydrogen = a gas that can burn and give energy
- in contrast = on the other side
- launch = here: to put into orbit
- light year = the distance that it takes for light to travel in one year = about 9 trillion kilometres
- revolve = move around
- solar system = a star with planets moving around it
- support = here: to have the elements that would allow life
- surface = the top layer of an object
- telescope = instrument with which you can see things far away
- temperate = not too hot and not too cold
- trillion = a thousand billion