Looking for a New EarthFor thousand

Looking for a New Earth
For thousands of years, humans have explored the Earth. Nowadays, we are exploring
space. Astronomers are the modern-day explorers. Currently, many astronomers are looking
for new planets and new places for humans to live in the future. But where do astronomers
starts looking?
First of all, astronomers look for a star. That’s because our own Earth orbits a star
(the Sun). More importantly, it is the correct distance from the Sun for heat and light. So
when astronomers have found the star, they look at the planets around it. In recent years,
astronomers have found nearly 400 new planets with stars. Unfortunately, many of these
planets are either too near to the star or too far away.
However, if the planet is in a good position, astronomers look for three keys things:
water, air, and rock. Water is important because all life needs water. Humans can drink it and
they can also grow plants with water. And plants produce air for humans to breathe and food
to eat. So all life on other planets will need water and air. Rock on a planet is also important.
That’s because there is often water under the rocks.
After many years of looking, astronomers have found a planet that is similar to Earth.
It’s Gliese 518g and it’s near a star. The astronomers think it has water and rock and the
average temperature is between -31 C and -12 C. That’s cold, but not colder than Antarctica
or the Arctic Circle, for example. Gliese 581g is bigger than the Earth and a year on
Gliese518 is only 37 Earth days instead of 365. But astronomers do not think these are big
differences and some of them think Gliese 581g will be a new Earth. However, Gliese 518g
is twenty light years from Earth- a distance of 18 trillion km.