Do we know everything about the Milky Way? A team of astronomers has arrived to change everything we know about our universe, and they have found strong evidence that super-Earths (planets larger than Earth but smaller than Neptune) could be much more common than previously thought! They discovered it thanks to a technique called gravitational microlensing. Don’t worry if you don’t understand it, keep reading and we’ll explain everything.
The study was led by scientists from the Harvard-Smithsonian Center for Astrophysics, and it reveals that one in three stars in the Milky Way could have a super-Earth. Isn’t that exciting?
What exactly is a super-Earth?
Although the term “super-Earth” might make us think that they could be habitable planets just like ours, a super-Earth is a planet larger than Earth but smaller than Neptune, so we are only referring to its mass with this name, but at no time (yet) do we know if they have water, if they are habitable or if we can send humans there, at least not for now.
They orbit far away
Until now, the super-Earths that had been detected were usually very close to their stars, with very short orbits, but this one they discovered is as far from its star as Jupiter is from our Sun, and it’s surprising because until very recently those planets had only been observed near the heat of their stars, but not anymore!
Gravitational microlensing: the key
This technique has been, without a doubt, the most novel, extremely precise, which allowed scientists to observe temporary changes in the brightness of a star when a massive object passes between it and Earth. Wait, we’ll explain it another way: it works like a giant magnifying glass. When an object passes between us and a star, its gravity amplifies the light.
But this technique wasn’t the only thing that made the discovery. The data from the Korea Microlensing Telescope Network (KMTNet), a network of telescopes in Australia, Chile, and South Africa, was also essential to detect this faraway planet.
Are there more?
The researchers didn’t stop with this single finding. They compared what they found with a larger database and reached an astonishing conclusion: distant super-Earths could be very common. More than anyone thought. The sample they analysed is three times larger than in previous studies, and with many small planets that had previously gone unnoticed.
Our solar system, the exception?
Until now, we assumed that our solar system was something like a default template, and that the rest of the systems would be similar to ours. But it turns out it could be rarer than we imagined. Instead of having giant planets like Jupiter and Saturn on the outskirts, other systems could have super-Earths in those same places. Ours would be the exception, not the rule.
And the possibility of life?
We would love to give you this answer, but it’s still too early to know. Although, a spoiler: their mere existence already expands the possibilities.
But the reality is that we still don’t know if they have an atmosphere, if they have oceans, or any condition that could allow life, and, careful, it doesn’t have to be human life. Maybe they are more primitive life forms, or maybe they are desertified planets, but as we said, it’s still too early.
This discovery, which seems small, completely changes the statistics, and of course, the strategy to continue searching for these super-Earths. Now we’ll have to take another look through the telescopes to search for these planets far from their stars. As one of the team’s astronomers said: “Finding a microlensing event with a planet is like finding a needle in a haystack of needles.” And yet, there they are. What else is left to discover?