Nasa have announced that liquid water "almost certainly" exists on Mars.
In a press conference, the space exploration agency said it has discovered that seasonal changes to the Martian landscape are caused by flowing water on the surface of the planet.
"Under certain circumstances, liquid water has been found on Mars" - Nasa Planetary Science Director Jim Green, said in the briefing.
Liquid water on the surface of Mars could support life and "may affect future human exploration," according to Nasa.
The live announcement has now ended.
Mysterious features on Mars that change with the seasons are almost certainly created by flowing liquid water, scientists at Nasa believe.
Latest satellite images have identified narrow streaks, typically less than five metres (16.4 ft) wide, that appear on slopes during warm seasons, lengthen, and then fade when conditions become cooler.
Experts have speculated that water might be involved in the formation of the gully-like features, known as recurring slope lineae, but only now has evidence supporting the theory come to light.
Liquid water could suggest that the surface of Mars is able to support life.
Nasa wrote: "Water is essential to life as we know it. The presence of liquid water on Mars today has astrobiological, geologic and hydrologic implications and may affect future human exploration."
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A 'fresh' crater on the surface of Mars has been snapped by Nasa's HiRise camera onboard the Mars Reconnaissance Orbiter.
Nasa said the closeup image of the impact crater was photographed on March 30th and shows it is located in the Sirenum Fossae region of Mars.
The crater, which Nasa said is new in geological terms, is believed to be fresh because "it has a sharp rim and well-preserved ejecta" - or debris field surrounding it.
An ancient ocean on the surface of Mars held more liquid water than the Earth's Arctic Ocean, scientists believe.Read the full story ›
A British woman who has been shortlisted to travel to Mars has described the feeling as "like queuing up for a rollercoaster".
Clare Weedon is one of five Brits down to the final 100 people who could be chosen for the one-way trip.
The 27-year-old told ITV News: "It's like queuing up for a rollercoaster - you're terrified but you're so excited."
The doomed Beagle 2 Mars probe may have been spotted near its intended landing site on the Red Planet, according to reports.
The UK Space Agency announced that it would provide an "update" on the ill-fated craft, which vanished while attempting a Christmas Day landing on the planet in 2003, in a briefing on Friday but is refusing to discuss in advance what will be revealed.
But according to the Times, a senior space scientist who has had sight of the images of Nasa's Mars Reconnaissance Orbiter said they showed an object "about the right shape and in about the right place" to be the lost lander.
The paper's source added: "It tells us how close it got to the right landing spot and that it was in one piece."
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