Huge Discovery! Scientists Find an Atmosphere Around a Rocky Planet That Could Support Life
Quick Summary
For the very first time, scientists have found an atmosphere wrapped around a rocky, Earth-like planet that orbits inside its star’s “habitable zone.” The planet is called LHS 1140 b, and it sits about 48 light-years away from us. This is one of the biggest discoveries in the search for life beyond Earth.
What Happened?
Scientists have been searching for alien life for decades. One of the biggest clues they look for is whether a planet has an atmosphere. Without an atmosphere, liquid water cannot exist on the surface. Without liquid water, life as we know it is nearly impossible.
Before this discovery, scientists had found atmospheres around planets — but only around huge, boiling-hot gas giants. Those are nothing like Earth. Finding an atmosphere around a small, rocky planet is a completely different thing.
Now, a team led by Collin Cherubim at Harvard University has done just that. They studied a planet called LHS 1140 b. It orbits a red dwarf star about 48 light-years from Earth. A light-year is the distance light travels in one year — so this planet is incredibly far away. If you could fly there at the speed of today’s fastest spacecraft, the journey would take hundreds of thousands of years.
LHS 1140 b is in the habitable zone of its star. That means it is the right distance from its star for liquid water to potentially exist on the surface — not too hot and not too cold, like Goldilocks and her porridge. The planet is a bit bigger than Earth, more than five times our planet’s mass, and about 1.7 times Earth’s width.
Using a powerful telescope, the scientists detected helium gas leaking away from the planet into space. That is the key clue. Helium escaping means the planet has a real atmosphere that keeps getting replenished. The findings were published in the top science journal called Science.
Why Does It Matter?
Before this discovery, every rocky planet scientists found in a habitable zone was a mystery — no one could tell if any of them had kept their atmospheres over billions of years. Harsh radiation from stars can strip atmospheres away, like a strong wind blowing away fog.
Now we know that at least one rocky planet, in the perfect temperature zone, has held onto its atmosphere for nearly five billion years — slightly longer than Earth has even existed. That is incredibly exciting. It does not mean there is life on LHS 1140 b. But it means a planet like it could have the right conditions to support life. Scientists will now study its atmosphere more closely to find out what it is made of.
As one of the study’s researchers put it: twenty years ago, scientists wondered if rocky planets like Earth even existed around other stars. Then we learned they are common. Then we found some in habitable zones. Now we know at least one has kept its atmosphere. Each step gets us closer to answering the biggest question of all.
Big Words
- Atmosphere — the layer of gas surrounding a planet, held in place by gravity; Earth’s atmosphere is made of mostly nitrogen and oxygen, which we breathe
- Habitable zone — the region around a star where temperatures are just right for liquid water to exist on a planet’s surface; sometimes called the “Goldilocks zone”
- Exoplanet — any planet that orbits a star other than our own Sun; there are thousands of known exoplanets
- Red dwarf — a small, cool type of star that burns much dimmer and longer than our Sun; they are the most common type of star in the galaxy
- Helium — a very light, invisible gas; the same gas that makes balloons float, and one of the gases scientists detected escaping from LHS 1140 b
Fun Fact
LHS 1140 b is nearly five billion years old — slightly older than Earth! That means its atmosphere has been doing its job for even longer than our own planet’s air has existed.
Think About It
If scientists eventually find signs of life in LHS 1140 b’s atmosphere, how do you think people around the world would react to the news?
Sources
- EurekAlert / Center for Astrophysics Harvard & Smithsonian — First atmosphere detected on a habitable-zone rocky world
- Gizmodo — Scientists Detect First Atmosphere on Rocky Habitable-Zone Planet
- ScienceAlert — For The First Time Ever, an Atmosphere Has Been Detected Around A Rocky Habitable Zone Planet
- phys.org — In search of life beyond our solar system: Atmosphere detected on a habitable-zone rocky world
- Universe Today — Astronomers have detected an atmosphere around a rocky planet in another star’s habitable zone