When planet hunter Kepler discovered the exoplanet Kepler-22b in 2011, it was big news. After all, this was the first time a space telescope had found an exoplanet located within the habitable zone of its star. This is an interesting result in the search for extraterrestrial life: is it possible that life exists or already exists on the Earth-like planet Kepler?
Kepler habitable zone
NASA describes the planet Kepler-22b as a super-Earth: A planet larger than Earth but with many similarities. For example, Kepler-22b is about 2.4 times the size of our home planet, and like us, orbits in the habitable zone around its star, which in Kepler-22b's case is Kepler-22. What does it mean? As you can see in the image below, Kepler-22b is close enough to its star to allow liquid water to exist, but not so close that the water on its surface evaporates.
Kepler-22b is located in the habitable zone of its star, just like Earth and Mars. The planets in the green orbit in this illustration are in the habitable zone.
Kepler-22b may be a rocky planet with oceans, just like Earth. But scientists are keeping their wits about them. It's also possible that this exoplanet is a gas giant, like Jupiter or Saturn, so Kepler-22b is unlikely to have life like ours.
We don't know this yet about the exoplanet Kepler-22b
Why is there still so much uncertainty about Kepler-22b? The fact that the Kepler space telescope was able to find this exoplanet was an achievement in itself. Kepler-22b is located 635 light-years from Earth. To give you an idea of how far away this really is, if you were driving a car on a hypothetical highway through space, the road trip to Kepler-22b would take seven billion years. A space probe like Voyager 1, the first to fly outside our solar system, is much faster but will take eleven million years to get there.
As a result, only limited research has been conducted on this exoplanet since the discovery of Kepler-22b. In the search for possible extraterrestrial life, the focus is currently on the planets and moons closest to Earth, such as Proxima Centauri B and Jupiter's moon Europa.
This is what life could be like on the planet Kepler-22b
But suppose life became possible 635 light-years away, what would that look like? So we don't know if Kepler-22b is a terrestrial planet or a gas giant. What did the Kepler space telescope discover? Kepler-22b takes 289.9 days to orbit its star. So it is not surprising that the year is much shorter than it is on Earth.
Because Kepler-22b operates in the habitable zone, the temperature may also be quite pleasant. If we assume that it is indeed a giant Earth with a liquid ocean, NASA estimates based on computer models indicate that the Earth's temperature on Kepler-22b is about 15.5 degrees Celsius. Excellent temperatures for life, but many questions remain unanswered. For example, does Kepler-22b have an atmosphere that retains heat? For now, the search for life on Kepler-22b remains a puzzle, with many pieces still missing.
Willick Van Doorn studied journalism, traveled the world for a while, and eventually ended up in the editorial offices of Quest, National Geographic, and Runner's World across the United States, Australia, and New Zealand. She is interested in the world, prefers to travel every month and always takes her running shoes with her.
