The ice covered Europa, one of the 79 known moons of Jupiter and the sixth largest moon in the Solar System, has captured the attention of scientists for decades. It is currently thought, that this unsuspecting world, may play host to some form of extraterrestrial life.
As our present knowledge suggests, imagining traveling to Europa, is to imagine a very alien world.
In the Jovian system, one year is equal to about 12 Earth years and distance wise, Jupiter is about 5.2 AU’s from the sun (one AU is the distance of Earth from the Sun). With an equatorial diameter of 1,940 miles, Europa is approximately 90% the size of Earth’s moon. Light from our sun, takes about 45 minutes to reach Europa and thus sunlight, is about 25 times fainter than it is on the Earth (1).
The satellite formed from the leftover material of gas and dust that initially condensed to form Jupiter. In fact, along with its Galilean siblings, Io, Callisto, and Ganymede, Europa is in a sense, apart of a mini solar system, since it manifested from the leftovers of Jupiter, in a similar way that Earth and the inner planets formed from the leftovers of our Sun (1)
Furthermore, just as the inner planets are less dense the further they are from the sun (Mercury being the most dense, followed by Venus, then Earth and Mars) the same goes in the Jovian System. IO the most volcanically active body in the solar system, is also the most dense out of the four Galilean moons.
Much of our knowledge of Europa is owed to the Voyager Spacecrafts, when they passed through the Jovian system in the late 1970’s and gave scientists a close up view of a mysterious body covered by a shield of water ice. The surface wide phenomena of deep cracks and shifting gorges, was and is still today, a focus of intrigue for astronomers.
Based on data from Voyager, the Galileo spacecraft and other ground based telescopes, it appears that these icy shifts and cracks are produced by tidal forces of a theoretical ocean beneath the 10-15 thick ice shell.
The data suggests, that because of the enormous crank on the moon by Jupiter’s gravity, the interior of Europa is heated, allowing for water to remain in liquid form.
It almost seems like something out of science fiction, a subsurface ocean that may have over twice the amount of liquid water as our own planet.
And its not just Europa that may be harboring an underground sea world, it’s Jovian companions Callisto and Ganymede might also posses one as well. Saturn’s moon Enceladus has been documented to shoot plumes of organic molecules out of it’s icy poles.
Yet it is still Europa that remains arguably, the most alluring of these deep space destinations. Europa is closer and more accessible than Enceladus and more is known about it than Callisto and Ganymede.
If NASA or another space agency, can send a sophisticated enough spacecraft out to the Jupiter system, with the sole intent of discovering the truth behind this alluring moon, than it is possible that space exploration and possibly, astrobiology, may take a giant leap forward.
Luckly, NASA is slated on launching the Europa Clipper probe which will map the surface of the moon, be carrying ground penetrating radar and attempt to discover the salinity of it’s ocean. Using a mass spectrometer, the probe will study the atoms and molecules of the atmosphere during flybys of its three and a half year mission. If NASA is lucky, the probe will be able to analyze the ions of plumes of water vapor that just might be geysering up from the satellite’s poles.
The spacecraft will not however, be making a landing on the moon’s surface which might be the ultimate goal of scientific discovery. Though, it may be possible to unravel the moon’s mysteries without drilling beneath the ice, thanks to the moons tidal forces that crack and shift the icy shell, making way for potential ocean contents to be pushed upward to the surface.
From orbit, Europa Clipper will attempt to detect any of these leaks and maybe, just maybe, be able to conclude whether there is life beneath the surface.
“We’re a habitability mission. We’re trying to understand, is Europa a habitable environment?” Europa Clipper project scientist Robert Pappalardo. of NASA’s Jet Propulsion laboratory said recently at the Oct. 23 International Astronautical Congress in Washington DC.
The probe will be taking the highest resolution photos of the satellite ever recorded and will be ten times sharper than the images taken by NASA’s Galileo spacecraft that orbited Jupiter from 1995 to 2003.
These photos will be sure to delight scientists and amateur Astronomers across the world but more importantly pave the way for a landing mission to the moon that is scheduled to occur sometime in 2030. Though at this time, Humans may have already landed on Mars so it will be interesting to see what discoveries or breakthroughs might divert or change NASA’s budget.