Relative sizes of planets that are in a zone potentially compatible with life: Kepler-22b, Kepler-69c, Kepler-62e, Kepler-62f and Earth (named left to right; except for Earth, these are artists’ renditions).
The ancient question 'Are we alone?' has graduated from being a philosophical musing to a testable hypothesis. We should be prepared for an answer.
Signs of life on Mars? These are the tracks of NASA’s Curiosity rover exploring the Martian landscape.
Mars has long captured our imagination, from claims of canals to Martian attacks and now our latest NASA exploration to look inside the red planet.
Once people get there, Mars will be contaminated with Earth life.
NASA/Pat Rawlings, SAIC
NASA's InSight Mars lander touches down Nov. 26, part of a careful robotic approach to exploring the red planet. But human exploration of Mars will inevitably introduce Earth life. Are you OK with that?
Pie in the sky? Mars Ice Home concept.
Elon Musk may be disappointed by recent studies threatening his plans to go to Mars, but planetary scientists are breathing a sigh of relief.
We can create the right kind of food plants to survive on Mars.
If humans are to live on Mars they will need a stable supply of food. Earth plants are not suited to the Mars climate but we can engineer plants that are.
Mars’ south polar cap, as seen from Mars Global Surveyor. Buried beneath, we now know, is a lake of liquid water.
Researchers have found evidence of a large lake of salty water, buried 1.5 kilometres beneath the southern polar ice cap on Mars. So what does that mean for life on the red planet?
Mars NASA JPL Caltech cd f d o.
The race may be on to send humans to live on Mars, but is it worth the effort -- and the spend -- when we have our own problems to deal with on Earth.
The Wdowiak Ridge on Mars as seen by NASA’s Mars Exploration Rover Opportunity.
NASA/JPL-Caltech/Cornell Univ./Arizona State Univ.
Clay on early Mars could have formed under hot and steamy conditions, challenging the idea that it was created just like that on Earth.
The Viking landers in the 1970s were the last to look directly for life on Mars.
Planetary protection protocols try to make sure we don't seed places like Mars with life from our planet. An astrobiologist argues they're misguided – especially with human astronauts on the horizon.
Anastasiya (left) and myself working on the Haughton crater rim.
Will humans ever live on Mars? Whoever it is to get there first will benefit from the experiences of those who stayed in simulated Martian missions here on Earth.
Even if alien life is never discovered, all is not lost.
A view from the ‘Kimberley’ formation on Mars taken by NASA’s Curiosity rover. The strata in the foreground dip towards the base of Mount Sharp, indicating flow of water toward a basin that existed before the larger bulk of the mountain formed.
We could learn a lot from any mission to send people to Mars, such as whether there's life elsewhere in the universe or even the technology for new household appliances.
Suited up to simulate the conditions of working outside on Mars. Jonathan Clarke (the author, left) with visiting engineer Michael Curtis-Rouse, from UK Space Agency (right).
Jonathan Clarke personal collection
One of the best ways to find out the challenges of living on Mars is to simulate living on another planet here on Earth. So what's it like to spend several months living the Martian life?
Ridges in the Dresser Formation in the Pilbara Craton of Western Australia that preserve ancient stromatolites and hot spring deposits.
Life on the land could have started millions of years earlier on Earth than first thought. This could change the way we think about life developing elsewhere in the universe.
The HI-SEAS mission gives people a chance to practise on Earth what life would be like on Mars. A crew member here from the 2015 mission.
Flickr/University of Hawaii/HI-SEAS
What's the best way to find out how people will cope with the journey to Mars and life on another planet? Lock a test crew up for a year in a simulation right here on Earth.
We’re on the hunt for life – what do we do when we find it?
A philosopher argues that now is the time to figure it out, before we make the inevitable discovery of extraterrestrial life.
Schiaparelli separating from Trace Gas Orbiter.
If we do find life on Mars, it will be difficult to prove that we didn't bring it there from Earth. An insider talks us through what's at stake.
The ALICE detector at the Large Hadron Collider may help unravel some of nature’s grestest mysteries.
Our panel of experts speculate on which of science's biggest questions could be answered in the coming months.
Unlike science fiction films featuring grotesque aliens and faraway galaxies, Ridley Scott’s The Martian depicts a sci-fi space mission that could soon be science fact.
20th Century Fox
NASA has set a target date of 2030 for a manned mission to Mars. With no real scientific breakthroughs needed, success depends on developing the proper technology.
This digital false-colour image shows the dark, narrow streaks on Martian slopes inferred to be formed by seasonal flow of water on the planet. The streaks are roughly the length of a football field.
Image Credit: NASA/JPL-Caltech/Univ. of Arizona
Now that we have discovered liquid water on the surface of Mars, what does this mean for the prospects of finding life there, past or present?