Two previously undiscovered Earth-like planets have been hiding in a solar system neighbouring ours, according to scientists.
Their sun, known as "Teegarden's star", is only 12.5 light years from us. It is also one of the smallest and dimmest known stars – making it, and the planets that it supports, very difficult to spot.
Because it is so dark, the star itself was only spotted in 2003, despite being so near to us. But it is also a relatively calm place, without violent solar flares or other activity that could wipe out anything that tried to live near it.
Now, scientists who have been studying that dim star say there are planets floating around it that look remarkably similar to ours – and could have the perfect conditions to support alien life of their own, too.
One of the two planets is said to be the most similar to our own ever to be discovered. That is calculated by how its size compares to the Earth and what the temperature might be like – although for now researchers only know its minimum mass, and not exactly how large it is.
On that planet there could be flowing water and rocky worlds. But they stress how much is left to learn about the worlds, and many of the current calculations are done using estimates.
Researchers say there is a 60 per cent chance of the planet having a temperate environment on its surface, and the temperature there is thought to be roughly in line with a day on much of Earth.
"The two planets resemble the inner planets of our solar system," lead author Mathias Zechmeister of the Institute for Astrophysics at the University of Göttingen, said in a statement. "They are only slightly heavier than Earth and are located in the so-called habitable zone, where water can be present in liquid form.”
Scientists are able to see the star from observatories on Earth. They hope to go on to further examine it, looking more at the activity and environment around it in the hope of learning more about how conditions could be on its planets.