Nasa Mars announcement: Red Planet could have building blocks of life, Curiosity rover shows – as it happened

The two studies appear in the journal Science. In a companion article, an outside expert describes the findings as "breakthroughs in astrobiology." 

"The question of whether life might have originated or existed on Mars is a lot more opportune now that we know that organic molecules were present on its surface at the time," wrote Utrecht University astrobiologist Inge Loes ten Kate of the Netherlands. 

Kirsten Siebach, a Rice University geologist who also was not involved in the studies, is equally excited. She said the discoveries break down some of the strongest arguments put forward by life-on-Mars skeptics, herself included. 

"The big takeaway is that we can find evidence. We can find organic matter preserved in mudstones that are more than 3 billion years old," Siebach said. "And we see releases of gas today that could be related to life in the subsurface or at the very least are probably related to warm water or environments where Earth life would be happy living." 

The methane observations provide "one of the most compelling" cases for present-day life, she said.

Nasa are very keen to stress that there's much more to come: chief among those future updates will be the ExoMars mission, which will arrive there this year. When it does, it will be specifically hunting for evidence of alien life – and all of these new findings will be expanded on by that work.

Similar announcements – both of methane and organic materials – have been made by Nasa before. But they are very keen to stress that these are very different from those, and represent a major breakthrough.

In terms of the methane, we have usually only found a small amount. This dramatically changes how much we can find, and seems to explain more of the mechanics behind the amount of methane we are seeing

And much the same is true of the previous discoveries of organic matter, too. This time around we've found more, in more detail, and in a more reliable way.

One thing this also does is helps inform questions of where else we want to land on Mars. We know now, for instance, that craters that might once have been lakes could be active and interesting places to head to – and so it's likely that we'll look for similar places next time we arrive there.

This could, perhaps, also inform questions about our colonisation of Mars. If the new findings are the result of energetic activity, for instance, it could provide important fuel if we come to live on the planet.

That's all for today's announcement – though as Nasa has stressed, the implications and consequences of the discoveries will continue to be examined and not fully understood for years.