G7 357d lies 31 light years away from our solar system and orbits in the Goldilocks zone of the GJ 357 system where water could form. The planet is a super-Earth meaning it is outside of the Solar System and has a greater mass than Earth, six times the size of Earth in this case, but lower than ice giant Neptune. As reported by NBC, Lisa Kaltenegger, an astronomy professor at Cornell University, explained: “It’s a distance from the star that is not too hot and not too cold.”
The discovery of the planet was not expected, it was a side-effect of the analysis of NASA data.
She said: “It was like a freebie, because it was discovered in the follow-up.
“I was on vacation at the time, and I was completely surprised.”
There are two other known planets in the system, GJ 357 b and GJ 357 c, but they are thought to be too hot for human life with the surface
temperature of the later, according to Ms Kaltenegger being 260F (127C).
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GJ 357d has an orbit of just over 56 days and is around 20 percent of the distance between Earth and the Sun.
Elisabeth Adams of the Planetary Science Institute said: “It’s a really good candidate to get atmospheric measurements, and that would tell us the composition or if there’s oxygen, and from there, that would tell us how habitable it is.”
Ms Adams also said the mass suggested aquatic life could be present on the planet.
However, the planet is far away.
Light years refers to the distance light can travel in a year.
The speed of light is a breakneck 186,000 miles per second.
This means light could travel around the Earth 7.5 times in just one second.
Thus in 31 years, light could travel around the Earth over 7.3 billion times.
The closest star to The Sun, Alpha Centauri is 4.37 lightyears away from our star.
