Are we alone in the universe? In 2008, the Phoenix Mars lander, launched by the United States, brought us closer to an answer when it detected water in a soil sample from the surface of Mars.
Scientists know that for life to exist, three basic things are needed: a source of energy (Earth uses the Sun), the building blocks of life (carbon, in our case) and water. Finding liquid water on Mars was a big step forward in the search for alien life.
Because Mars is one of the closest planets to Earth, scientists have been especially interested in exploring it. Beginning in 1960, Russia (then the Soviet Union) and the United States have attempted to send more than 40 missions to Mars.
Many of these spacecraft, whether flyby space probes, craft orbiting the planet or those that landed on the surface, sent back useful data to help scientists analyze Mars.
For instance, in 1976, the Viking 1 and Viking 2 spacecraft landed on Mars and sent back data showing evidence that there had once been water on the planet.
Where is that water now? Over millions of years, Mars became too cold and its atmosphere too thin for liquid water to last on its surface. Instead, the water vaporized. Only frozen water (ice) has been found at the planet’s poles.
On August 6, 2012, NASA rover Curiosity landed in a crater on Mars. Its mission: to assess if the soil there has, or ever had, the right conditions to support life. Curiosity’s soil tests have already shown that long ago there was likely flowing water in the area.
In November 2012, the spacecraft MESSENGER confirmed the presence of ice on Mercury. Scientists eagerly await more results about Mars, Mercury and the other planets.
Finding evidence of liquid water in Mars’s past makes scientists even more determined to continue their search for life there.
Could there be life somewhere beyond Mars? Experts carefully examine any meteorites that land on Earth for bacteria or other tiny organisms that could have come from some other planet. And they continue to look for water on planets and moons in our solar system.
Now they’re also using space telescopes to search for life beyond our solar system. Some scientists think that Alpha Centauri, Earth’s closest star system, may contain planets that can support life.
Between 2030 and 2035, the European Space Agency plans to land humans on Mars. What do you think they will find?