Aliens could be living in the acid clouds of Venus say Nasa (though they are only likely to be tiny bacteria)

Blooms of space-algae might have been spotted in planet's upper atmosphere

Its clouds hold large amounts of sulfuric acid and reflect 75 per cent of sunlight

The planet has been dubbed Earth's evil twin because of its inhospitable surface 

Aliens could be living in the acid clouds of Venus, a study backed by Nasa says.

Researchers think the sulfur dioxide-rich upper atmosphere of the planet might be home to simple microbial life.

Scientists used space probes to detect dark patches around the rust-coloured body, which resemble the light-absorbing properties of bacteria on Earth.

Venus' upper atmosphere is made up of sulfur-dioxide and droplets of sulfuric acid which fall to the surface as rain

The mysterious patches could be blooms of space-algae, similar to those which occur in lakes and ponds.

Venus' cloud are partly made of sulfuric acid and reflect 75 per cent of the sunlight that falls on them, making them completely opaque.

The planet has been dubbed Earth's evil twin because of its incredibly inhospitable surface conditions, where it rains acid and is 462C.

The planet has been dubbed Earth's evil twin because of its incredible heat and acid state

The research, published earlier this week in the journal Astrobiology, suggests extra-terrestrial microbes could survive by being blown around by winds in the cooler cloud tops.

Paper co-author and biological chemist at California State Polytechnic University, Pomona, said: 'On Earth, we know that life can thrive in very acidic conditions, can feed on carbon dioxide, and produce sulfuric acid.'

Venus once had a habitable climate with water on its surface for as long as 2 billion years.