Watch the video above: A NASA astrobiologist explains why Europa holds such promise for life.
Editor’s note: A previous version of this post listed the amount of funding as $1.3 million rather than $1.3 billion. The post has been corrected.
TORONTO – When NASA announced its budget request of $18.5 billion earlier this week, the one allocation that received a lot of attention was a mission to Jupiter’s moon Europa.
What makes this moon worthy of $1.3 billion in funding? The fact that there is a chance that there could be life on Europa.
Europa is one of the 50-plus moons of Jupiter. It is also one of the four largest.
In 1979, NASA’s Voyager 1 and 2 spacecraft made the closest approach to Europa to date. What it found was evidence that suggested the surface was relatively young. As well, the way the cracks on the surface behaved suggested that the surface could move independently of its interior. This led scientists to believe that a layer of liquid or slightly warmer ice lay between the crust and the interior.
But it was in 1995 that things began to get even more interesting.
NASA’s Galileo spacecraft arrived at Jupiter in 1995. Its findings led scientists to believe that, beneath the icy surface was an ocean of salt water.
How can a moon that lies about 778 million km from the sun be warm enough to sustain liquid water? The answer is tidal forces.
Tidal forces are felt by all objects that are acted upon by gravity. As Europa orbits Jupiter — an immense planet with great mass — in an ellipse, it flexes and stretches. Think of a stress ball: as you squeeze it over and over, it generates heat (your hand will also create heat on the object, of course). That’s the same deal with Europa. Heat is generated in its interior.
Scientists believe that there are three ingredients for life as we know it: water, essential chemistry and energy.
Evidence strongly suggests that there is likely water on Europa. So what about the other two?
Well, Europa’s surface is mainly water ice, but radiation from Jupiter can alter the chemistry of ice. Water and materials on the surface may produce elements essential for life. Not only that, but there could be hydrothermal vents beneath the icy surface. Here on Earth, organisms are found thriving at these locations.
As for the energy, it’s the tidal forces that produce that which can trigger the chemical reactions.
The European Space Agency has its own mission, called the Jupiter Icy moons Explorer (JUICE) set to launch in 2022 to the planet where it will explore its moons. (NASA’s Juno spacecraft will reach Jupiter in July 2016, where it will study the planet, not its moons.)
Though $1.3 billion will be a drop in the bucket for a mission to Europa (the Mars Curiosity rover mission cost $2.5 billion; Cassini’s mission to Saturn cost more than $3 billion in partnership with the European Space Agency), it illustrates that NASA has set its eyes on reaching out to deep space to look for life elsewhere in our solar system. And, if the budget gets approved, astronomers around the world will be anxiously awaiting a mission that could change the way we view life in our solar system.
To ready more on NASA’s Europa study, click here.