Venus could have alien lifeforms in its clouds, scientists have suggested.
Alien
Experts from Cardiff University, MIT and Cambridge University have claimed that the planet could have the colourless gas ammonia in its clouds.
Tests show that life would be able to survive on the planet despite the level of acidity.
The study's co-author Dr. William Bains, from Cardiff University's School of Physics and Astronomy, said: "We know that life can grow in acid environments on Earth, but nothing as acid as the clouds of Venus were believed to be.
"But if something is making ammonia in the clouds, then that will neutralise some of the droplets, making them potentially more habitable."
The scientists believe that the ammonia on Venus has biological origins rather than from natural forces.
Professor Sara Seager said: "Ammonia shouldn't be on Venus.
"It has hydrogen attached to it, and there's very little hydrogen around. Any gas that doesn't belong in the context of its environment is automatically suspicious for being made by life."