This extraordinarily detailed picture shows exactly where the most methane, taken as an indication of life, can be found.

Appropriately enough for the sphere dubbed the Red Planet , the scarlet areas are the places where scientists have detected the most of the gas.

The picture was released by NASA just days after the U.S. space agency confirmed the presence of methane on Mars.

It is the first  ‘definitive proof’ of plumes of the gas seeping from the planet’s northern hemisphere.

And it is the strongest hint yet that alien microbes could be thriving deep below the red, dusty surface.

On Earth, 90 per cent of the methane produced is released by living organisms far beneath the soil.

‘It might be possible for similar organisms to survive for billions of years below the permafrost layer on Mars, where water is liquid, radiation supplies energy, and carbon dioxide provides carbon,’ said NASA scientist Professor Michael Mumma.

Three large telescopes based in Hawaii revealed that the colours absorbed by gas in Mars’ northern hemisphere during the planet’s summer match those absorbed by methane on Earth.

The revealing colours were detected using specialist high-dispersion infra-red spectrometers, which can reveal the chemical make-up of gas.

‘One of the plumes released about 19,000 metric tons of methane,’ Professor Mumma said.

Methane was detected on Mars as early as 2003 but scientists claimed it could have been dumped on the planet by comets.

The latest discovery is proof that the gas is actually produced by the Red Planet.

There is not yet enough information to know for sure whether the methane was a product of biology or geology, Professor Mumma said.

But he added: ‘It does tell us that the planet is still alive, at least in the geological sense.

‘It is as if Mars is challenging us, saying “hey find out what this means.”‘

British scientists welcomed the discovery, published in the journal Science.

Professor Colin Pillinger, the Open University scientist behind the failed Beagle 2 Mars probe in 2003, said: ‘Methane is one indicator of life – and this is still more circumstantial evidence.

‘We only have methane on the Earth because it is pumped into the air by life forms, or because it comes out of volcanoes. The only way to prove it is produced by life on Mars is to go and have a look.’

No active volcanoes have ever been spotted on the Red Planet.

Nasa’s next probe to Mars will be sent in 2011. However, it will be poorly equipped to study methane and discover whether it comes from life.

The best chance to settle the life question will come in 2017 when Europe’s ExoMars robotic mission is due to land on the Red Planet.

The methane levels peak during the warmer summer months, providing the strongest hint yet that alien microbes could be thriving deep below the red, dusty surface.