What is Humanity’s best bet to find life outside Earth? If you had asked this question in the 1980s to a NASA Viking Mission scientist, he would probably say, “We’ll know in a couple of years for sure”.
Today nearly half a century after NASA’s Viking Mission to Mars, hopes of finding life on Mars have slowly faded away. In these last 50 years, scientists have come to grips with how hard it is to find life outside of earth.
We could detect biosignatures from exoplanets and infer the existence of life on that planet, but we can never directly observe them. At Least with the current technology that we have. Therefore most of the questions about extraterrestrial life have the chance to go unanswered.
But if we can detect life in our backyard, that is, our solar system, it would be one of the most intriguing discoveries. Mars, being closest to Earth, had given a lot of hope to scientists which have slowly faded away.
Though, In the last few decades, a new possibility has come to light, and a very convincing one- Jupiter’s Moon, Europa. Europa might be our best bet to find life outside of Earth. But how do we plan to learn more about this strange moon?
Why is it so intriguing and important to us? We’ll talk about that and more.
Europa Clipper Mission: Finding Alien life in the oceans of Europa
Life has formed and evolved on Earth in even the harshest of conditions. Today we know life can form and thrive in the most extreme environments on Earth. And Europa’s Environment might not be so extreme. Life on earth requires three things: a source of energy, a liquid solvent like water, and elements that can form complex molecules and organisms.
Jupiter’s moon Europa might have all these three things. Today Europa is believed to be our best bet to find extraterrestrial life by many scientists. In 2024, NASA’s spacecraft, Europa Clipper will be launched aboard SpaceX’s Falcon Heavy Rocket, on a mission to determine whether Europa can support life.
Seven years after the launch, Clipper is scheduled to make its first encounter with Europa on March 7, 2031. This will be the first-ever mission by humanity to explore an oceanic world besides Earth. The Clipper Spacecraft will perform 50 close flybys of Europa from its lengthy orbit around Jupiter.
Europa Clipper will help us comprehend the potential for life on potential ocean worlds in our solar system and beyond by evaluating whether Europa has the three basic requirements for life to exist- a source of energy, a liquid solvent like water, and elements that can form complex molecules and organisms.
Europa is slightly smaller than earth’s moon and is covered with an ice shell roughly 12 miles thick. Under this ice shell, lies a liquid saltwater ocean up to 100 miles deep, which is twice the amount of water than on Earth’s oceans.
No sunlight reaches Europa’s ocean floor but vents on the ocean floor may release heat from the moon’s core. Similar vents in the darkest, deepest parts of Earth’s oceans can be found teeming with life- no sunlight required.
Similar vents can be discovered thriving with life in the deepest, darkest areas of the Earth's seas no sunshine is necessary. Though Europa Clipper cannot directly detect life, it is designed to answer very specific questions about the plausibility of life on Europa.
NASA always designs missions with big questions in mind, but they can only answer smaller specific questions. As a result, scientists are investigating various characteristics of Europa and doing simulations to fine-tune the questions that the expedition will need to ask. The spacecraft will enter Jupiter’s orbit and perform approximately 50 close flybys.
It is outfitted with highly sophisticated instruments– a mass spectrometer to investigate the contents of the surface ice, a magnetometer, radar to investigate the structures under the surface, and many more. But there might be a question bugging you!
Being a distant frozen world from the sun, How could life survive and evolve on Europa? Well, beneath the icy shell of Europa is briny water, mixed with minerals that are partially frozen but are also liquid enough to have convection. Below the saltwater lies a vast liquid ocean with more than double the amount of water found in Earth's seas.
Because of tidal pressures from its giant parent, Jupiter, Europa is not frozen solid (as it would be given its size and distance from the sun). These tidal pressures alter Europa, creating friction and heating. Scientists also predict the presence of volcanoes on the ocean floor which might be feeding the oceans with rich minerals.
So if you have Heated, lots of minerals, and liquid water, you have the three basic ingredients for life. Even though sunlight is still missing, we have seen chemosynthetic organisms on earth that live near the ocean floor vents and feed off the rich minerals.
They can feed off the sugar to get energy. So it might be that chemosynthesis is going on in the oceans of Europa. But you might notice another problem here– the need for oxygen. The oceans on Earth are oxygen-rich due to photosynthesis, which utilizes sunlight to convert carbon dioxide and water into sugar and oxygen.
There should be no photosynthesis taking on beneath Europa's ice, which can mean no oxygen and hence no life. So does that mean our last and best hope for finding extraterrestrial life is a disappointment?
Well, not really. There is still hope for life on Europa. The frozen moon has oxygen at its surface. When sunlight and charged particles from Jupiter impact the moon's surface, oxygen is produced.
But there's a problem: Europa's vast ice cover acts as a barrier between the ocean and oxygen. Because Europa's surface is frozen solid, any life must exist in its huge ocean.
How does oxygen go from the surface to the ocean?
According to new research, pools of saltwater in Europa’s icy shell could be transporting oxygen from the surface to the ocean floors. The process begins with charged radiation particles striking Europa's surface, breaking down the water ice into hydrogen and oxygen.
Because hydrogen is so light, it floats away. The oxygen, on the other hand, primarily remains on Europa's surface, with some dissolving into the thin atmosphere. This surface oxygen dissolves into Europa's surface ice, generating small oxygen bubbles.
The simulation is concerned with the fate of these little bubbles; will they sink into the ocean? In certain regions of Europa, also known as “Chaos Regions”, because of their complex surface features, the icy shell is thinnest.
Chaos Terrain makes up fissures up to up, faults, and flats. The specific causes of Chaotic Terrain are unknown, however, they are most likely connected to uneven subsurface heating and melting. This curiously lovely feature is highlighted in some of Europa's most memorable photos.
The ice on Europa's surface is 15-25 km thick, but it may be just 3 km thick in the Chaotic Zones, which encompass 25% of the moon's surface. Warmer briny water may be pushing up in certain areas, weakening the ice, and bursting through to the surface on occasion.
The simulation reveals that in some regions, there may be Porosity Waves (similar to a human wave in a stadium, but with porous pieces of ice) and that these porosity waves may carry oxygen bubbles down through the saline ice to the deep ocean.
This process can take thousands of years, but once it's started, it would provide a constant stream of oxygen from the surface to the ocean in substantial amounts — enough to maintain a life-supporting environment. The connection between chaotic terrain and oxygen transport is not entirely established.
However, scientists believe that convective upwellings induced by tidal warmth partially melt the ice, resulting in the surface's tangled chaotic topography. For the oxygen-rich brine to drain into the ocean, the ice beneath the brine must be molten or partially molten.
According to the findings, around 86 percent of the oxygen taken up at Europa's surface makes its way to the ocean. That proportion might have altered dramatically during the moon's history. However, the researchers' model produces an oxygen-rich ocean that is quite similar to Earth's. Is there something living beneath the ice?
We know that Europa possesses helpful molecules on its surface, such as oxygen, but do such compounds make it down into the ocean below, where life may utilize them? If true, this is an interesting prospect that might address Europa's "dark life" dilemma. And this is where the importance of the Clipper'sof mission comes into play.
Outfitted with this new hypothesis, the highly sophisticated instruments on the spacecraft could investigate the credibility of this process and hypothesis. It may detect oxygen concentrations on Europa's surface, and the radar could record what's going on under the surface. Clipper is meant to examine the subject of life on Europa, however, it can only study proxy questions.
The devices are not intended to discover life directly, but rather to answer scientific questions about how likely life is, and studies like this one are critical to the study that Clipper will do. The Clipper mission is the first dedicated to Europa.
We believe we know a lot about Europa but haven't been able to confirm it. On top of this, the Clipper mission will also lay the foundation for future Europa missions, especially a lander mission on Europa.
Which can directly detect life. The Clipper is intended to achieve three major goals:
Examine the ocean's composition to see whether it has the elements required to support life.
Investigate the moon's geology to learn how the surface, particularly the chaotic landscape, developed.
Determine the thickness of the ice shell and whether or not there is liquid water within and underneath it.
They will also influence how the ocean interacts with the surface: Is there anything in the ocean that rises to the surface through the shell? Is there any stuff from the surface that makes its way into the ocean?
Like the famous saying from Jurassic Park, “Life finds a way”: If there is energy and other basic ingredients for life in the oceans of Europa, life will likely find a way.
So what do you think about the possibility of alien life in the oceans of Europa? How will it change our understanding of science? Let us know your thoughts in the comment section.