Nasa is making big promises for Monday, saying it will reveal the answer to a major mystery about Mars.

The US space agency said it would be announcing "a major science finding" regarding the Red Planet at 11:30am EDT (4.30pm in the UK) on the 28 September, to be broadcast live on its website.

There is much speculation that the mystery to be addressed is the phenomena known as 'recurring slope lineae', the dark tendrils observed on the planet surface during warm seasons, which it is speculated is evidence of water.

Among those speaking at the briefing will be Alfred McEwen from the University of Arizona in Tucson, who in July published a study on slope activity in Mars's Gale crater, and Lujendra Ojha, a PhD candidate from the Georgia Institute of Technology in Atlanta who has collaborated with McEwen and has also studied the possible water activity on Mars.

Science and technology website Inverse.com highlighted Ojha as "the odd-person out at the news conference", pointing out that it was Ojha's undergraduate research that helped identify the recurring slope lineae.

The existence of water would be significant as it would mean there was a prospect of life on Mars.

A Martian's view of Mars Show all 3 1 /3 A Martian's view of Mars A Martian's view of Mars The jagged rim on the Victoria Crater on Mars: http://ngm.nationalgeographic.com/2008/12/planet-mars/updike-text?pid=independent_mars NASA A Martian's view of Mars The rover Opportunity leaves tracks on the surface as it plots a route automatically, avoiding obstacles: http://ngm.nationalgeographic.com/2008/12/planet-mars/updike-text?pid=independent_mars NASA A Martian's view of Mars Water/ice clouds drift over Mars' ancient volcanoes. The discovery of signs of water under the planet's surface suggest it was once hospitable to life: http://ngm.nationalgeographic.com/2008/12/planet-mars/updike-text?pid=independent_mars NASA

Also speaking will be Nasa heavy-weights Jim Green, the agency's director of planetary science; Michael Meyer, the lead scientist for the Mars Exploration Programme; and Mary Beth Wilhelm from NASA’s Ames Research Centre.