The concept of extraterrestrial life is often associated with outlandish science fiction hypotheticals, little gray Martians, and conspiracy theorists donning tin-foil hats. Despite its seemingly fantastical nature, scientists continually look towards the vastness of space seeking to answer the big question: Are we alone? Around 778 million kilometers away from Earth, Jupiter’s fourth largest moon, Europa, orbits the gas giant. This formerly inconspicuous moon has been the one of the centerpieces of discussion ever since scientists discovered ice on its surface in the 1970s.1,2 With recent groundbreaking findings, deniers of extraterrestrial life have certainly been given even more of a run for their money.
For extraterrestrial life to exist, its home planet should have these three basic requirements, similar to what we need on Earth3:
- Liquid water
- Specific elements like carbon, hydrogen, oxygen, and sulphur
- An energy source
Evidence of the first requirement, liquid water, was found by researchers examining images of the Voyager spacecraft’s flyby near Europa in 1979.2 The moon was adorned with dark cracks and veins which suggested the presence of a once-active surface that now exists as ice.2 While not liquid, the presence of ice may suggest the potential for liquid water to exist, which could potentially harbour life. Interestingly, the surface of the planet was also lacking in craters, indicating that there may have been a force that removed them, like flowing ice.2 Given these promising findings, NASA launched the Galileo mission in 1995 in search of further information through flybys of Jupiter and its moons.2 Among the data gathered from the mission, the most intriguing finding was that of Jupiter’s magnetic field, which Europa appeared to be disturbing around its vicinity.2 Researchers believed that this may have been caused by the presence of a saltwater ocean spanning the entire moon.2 However, if the moon is covered in ice, where is this ocean? Like the polar ice caps on our own planet, the ocean was theorized to be lying underneath the ice, running an estimated 15-25 kilometers thick over a 60-150 kilometer deep ocean.2
With the evidence collected, Europa became one of the leading contenders for hosting extraterrestrial life. This caused it to fall under intensive study by researchers aiming to uncover more evidence of life, or systems that can support life. In September of 2023, a crucial indicator for life was uncovered as two teams of scientists found carbon dioxide (CO2) on the moon’s surface using data from NASA’s James Webb Space Telescope.4 Moreover, closer analysis identified that the CO2 was being emitted from the ocean underneath the ice as opposed to external inputs like meteorites.4 It would be specifically coming from a single region of the moon called Tara Regio, spanning around 1800 square kilometers, suggesting that this particular localization hosts this peculiar anomaly.5
What makes the discovery of carbon so groundbreaking, is that carbon is crucial for biological life; it’s what we, as well as every living organism on Earth, are made out of.6 The specific structure and properties of carbon uniquely allow it to form complex molecules that permit life to exist in its intricacy.6 Paired with the presence of water, life is provided with a medium by which it can move and exist in basic forms. This similarly parallels how life on Earth originated as simple organisms in the ocean.6 Given the potential suitability for life, NASA will be sending a spacecraft on the Europa Clipper mission to conduct a detailed investigation of Europa in 2024.3 It’s set to orbit Jupiter in 2030, where we will hopefully gain further knowledge of what lies on this moon.3 As we anticipate the mission ahead, the presence of carbon on Europa provides compelling hope for the potential for life beyond our planet.
1. How far away is Europa from Earth. 2023 Jun 17. Astrophotography Lens. [accessed 2023 Oct 13]. https://astrophotographylens.com/blogs/astro/how-far-away-is-europa-from-earth
2. Europa: FACTS – NASA Science. NASA. [accessed 2023 Oct 13]. https://science.nasa.gov/jupiter/moons/europa/facts/
3. NASA’s Europa Clipper. 2014 Jun 3. NASA. [accessed 2023 Oct 13]. https://europa.nasa.gov/
4. NASA’s Webb finds carbon source on surface of Jupiter’s moon europa. 2023 Sep 27. NASA. [accessed 2023 Oct 13]. https://www.nasa.gov/solar-system/nasas-webb-finds-carbon-source-on-surface-of-jupiters-moon-europa/
5. Oakes N. 2023 Oct 5. Scientists found CO2 on Europa. here’s why it’s important . Astronomy Magazine. [accessed 2023 Oct 13]. https://www.astronomy.com/science/scientists-found-co2-on-europa-heres-why-its-important/
6. Eight ingredients for life in space. Natural History Museum. [accessed 2023 Oct 13]. https://www.nhm.ac.uk/discover/eight-ingredients-life-in-space.html#:~:text=Carbon%20molecules%20are%20also%20strong,’