When people think of aliens and living beings on other planets, they think of sci-fi movies and fiction and fantasy books.
However, recently, NASA has discovered a new solar system only 40 light years away that has seven exoplanets, and that just might have life!
An exoplanet is defined as any planet that is not part of our solar system. These newly discovered seven planets orbit the dwarf star TRAPPIST-1.
Dwarf Stars And New Worlds
A star is a massive, bright ball of energy held together by its own gravity. Stars can be divided into two distinct groups: giants, which are brighter than the sun; and dwarfs which are fainter stars and include our Sun.
There are six types of dwarf stars: red, yellow, blue white, black and brown—our sun is a yellow dwarf. TRAPPIST-1, discovered in 1999, is a red dwarf and they tend to be small, cool stars with temperatures under 4,000 Kelvin.
How are planets orbiting these distant stars discovered? The most common method is called transit photometry. Astronomers point a telescope at the star to continuously monitor the intensity of light coming from it. If there is a dip in the light and it happens at regular intervals, there is a good chance a planet is orbiting around it (see NASA animation HERE).
By measuring how long it takes planets to pass in front of the star, how much light it blocks, and how often they orbit, scientists can calculate the masses of these planets and their distance from the star.
What We Know So Far...
This latest discovery is the largest number of exoplanets found at any one time. This new solar system is so tiny that all seven planets are as close to TRAPPIST-1 as Mercury is to the Sun!
Furthermore, while it takes Mercury 88 days to go around the Sun, it takes the outermost exoplanet only 20 days to orbit the star TRAPPIST-1. Also, since TRAPPIST-1 is a cool star, liquid water could exist on any of the seven planets.
Scientists have been focusing on the three exoplanets in the habitable zone (called the “Goldilocks Zone”) which are most conducive to life. Planet E even gets the same amount of starlight and is the same size as Earth.
Apart from the exciting possibility of life on these planets, scientists have also made a few other observations. Due to their density, all the planets would most likely be rocky. Also, the planets are so close to each other that if you were standing on one, you would be able to see a wonderful, up-close look at the other planets!