Has Nasa found life on Mars? Speculation mounts ahead of press conference to unveil "a major science finding. Nasa is preparing to unveil a "major science finding" from its Mars exploration programme, amid speculation it could have found water flowing on the Red Planet.

Has Nasa found life on Mars? Speculation mounts ahead of press conference to unveil "a major science finding

Nasa is preparing to unveil a "major science finding" from its Mars exploration programme, amid speculation it could have found water flowing on the Red Planet.

The space agency has scheduled a press conference for Monday, in which it promises to announce a "Mars Mystery Solved".

While many are hoping for a discovery of alien life, the leading theory among those who follow research into Mars is an announcement of the presence of liquid water.

The speculation has been driven by Nasa's disclosure that Lujendra Ojha, a PhD candidate who discovered possible signs of water as a 21-year-old undergraduate student in 2011, will be speaking as part of the announcement.

Scientists have long known that there is frozen water at the poles of Mars, but have yet to find it in liquid form.

Any such discovery would raise the chances of life being able to be sustained on the Red Planet, as all life on Earth requires water.

Mr Ojha’s initial discovery involved using computer editing to review images of a crater on Mars, which had gullies that were thought to be remnants of historical water activity on the planet.

As part of the work he by 'accident' discovered changes in the appearance of the slope of the crater, with “finger-like” features that scientists said could be liquid, briny water.

Such a discovery could pave the way for the search for life on the Red Planet, which Mr Ojha described at the time as “the holy grail of science”.

Doug McCuistion, former head of NASA’s Mars program, said a discovery of free-flowing water would be “game-changing”.

He told the Boston Herald: “If they’re announcing that they’ve found easily accessible, freely flowing liquid water under the surface — which is one of the theories we’ve been hearing for years and years — that has massive implications both for the potential for life on that planet and sustainability of humans.”

Oxygen and water supplies are major challenges to putting man on Mars – so finding water is already there could significantly “lighten the load” of any manned mission, he said.

Nasa’s Mars rover, Curiosity, has been exploring the Gale Crater on the planet since 2012 and found tantalising clues of possible life.

In December it discovered 'burps' of methane, which Nasa scientists said could indicate “life or evidence of ancient methane trapped which could show ancient life”.

Nasa's Curiosity Rover has been on Mars since 2012  Photo: JPL-Caltech/NASA/EPA

Most methane on Earth is produced as a waste gas by living organisms and scientists suggested the gas encountered on Mars could be from bacteria.

If that were confirmed it would be the first evidence of life outside Earth.

Earlier this year the Mars rover also found calcium perchlorate – a type of salt – in the soil, suggesting that salty liquid water could be present close to the planet’s surface.

Calcium perchlorate lowers the temperature at which water freezes, which could allow it to remain in liquid form even on Mars, where temperatures drop to -125 C in winter.

The salt also absorbs water from the atmosphere, dragging it down into the surface.

Tiny creatures have been discovered on Earth that can live entirely on brine, without oxygen, raising the possibility that a briny liquid on Mars could be home to some sort of primitive alien life-form.

The question of life on Mars could finally be answered by a new rover from the European Space Agency that is due to land on Mars in early 2019 and will be equipped with a two-metre drill and the ability to detect biomarkers of life.

The latest research is due to be published at 4pm today in the journal Nature Geoscience, followed by a Nasa press conference at the space agency’s headquarters in Washington.