Could Europa Harbour Extraterrestrial Life?

Are we alone in this universe?  Are there other planets having intelligent life? Where are these planets? How do we find them? These are questions that are baffling scientists for decades. Surprisingly, we don’t yet have an answer to them. But the search never ends. 

Several factors help in sustaining intelligent life. Take a look here on earth. Our major source of life was water. Water facilitated the growth of cells and evolution took the job. And here we are atop the food chain.

A nourishing atmosphere helps us to breathe and also protects us from harmful cosmic rays. The internal heat of the earth helps us stay in balance. But there may be different ways and different situations that could aid in intelligent life. 

Our best bet now is far away on Jupiter’s natural satellite, Europa.

Jupiter and Europa

The Galilean moons. From left to right, in order of increasing distance from Jupiter: Io, Europa, Ganymede, Callisto.
The Galilean moons. From left to right, in order of increasing distance from Jupiter: Io, Europa, Ganymede, Callisto. By NASA/JPL/DLR

Jupiter is the largest planet in the solar system. It lies at the beginning of the outer solar system. Jupiter is the fifth planet from the Sun.  It is a gas giant that is almost 1,300 times the size of the earth.

It is so massive that it is 2.5 times more massive than all the other planets in the solar system combined. What is interesting about Jupiter is that it has 79 known moons? One of them is the famous Europa

Europa is the sixth closest moon to Jupiter by distance. It is part of the four Galilean moons orbiting Jupiter. Europa is the smallest Galilean moon by comparison. Of all the moons in the solar system, it is the sixth-largest.

Found by Galileo Galilei in 1610, it was named after the Phoenician mother of King Minos of Crete and lover of Zeus, Europa. 

Size comparison of Europa
Size comparison of Europa (lower left) with the Moon (top left) and Earth (right). Credit: NASA

Europa is a peculiar natural satellite. It is slightly smaller compared to Earth’s moon. Astronomers call it one of the most beautiful moons in the solar system.

What makes it so beautiful is its extravagant water-ice crust. The surface has little to no impact craters of any sort. It has the smoothest surface of any object in the solar system. This suggests that it could be a very young moon.

Scientists believe that this icy crust could be holding water oceans beneath it. In fact, there is evidence of geysers on the surface suggesting the presence of water inside.

The cracks and lines on its surface could be because of water activity under the crust. This could be causing ice movement on the crust similar to the plate tectonics on earth. Scientists believe that the oceans could harbour extraterrestrial life.

One new research might just crack the code.  

Water Oceans Under Icy Europa

Europa – possible effect of radiation on biosignature chemicals.
Europa – possible effect of radiation on biosignature chemicals. By NASA/JPL-Caltech

Among all the other places in the solar system, Europa is one place where scientists believe could support life. Its water oceans underneath the icy crust should be able to trap enough heat from the core to sustain life.

But this is just an assumption, as we don’t have any inside knowledge on what goes on under the thick crust. All the information we have about the moon is from the Galileo mission by NASA. But the Europa Clipper program, set to launch in 2025, should help us uncover more about the moon. 

Before the mission, a team of scientists is finding a new trick to get to know what lies under its thick crust. Since no probe will be able to get inside our best bet would be analyzing it from the outside. They are planning to do this using the help of a peculiar phenomenon that makes the moon ‘glow in the dark’.

Murthy Gudipati and Bryana Henderson of NASA along with Fred Bateman at NIST are the scientists behind the research.

A Show of Colours

The team relies on the colours of light that the moon’s ice puts out when hit with radioactive particles. Now, Jupiter and its moon Io might put out a lot of radioactive particles that get accelerated by magnetic fields. These particles may have hit Europa’s surface.

The result of this process is something familiar, the invisible ink effect. The invisible ink is visible only when ultraviolet light falls on it. Similarly, when electrons bombard the crust, it releases different colours of light. The different colours are associated with the chemical composition of the water oceans inside the crust. 

The team freeze-dried different salts mixed in water and shot electrons at them. They then observed the colours that come out. Each salt shows different colours when exposed to radiation.

They hope that the same principle can apply to the water oceans inside Europa. One thing is that it will have several salts inside and so they don’t know the exact spectrum that they will find. 

Since the Clipper Program is not due till 2025, there is still time for many more experiments and data collection. If the final results come out positive, it could change the entire perspective on life in the Universe. 

The study was published in Nature Astronomy on 9 November 2020.

Read more on Europa, probably glows in the dark, and that may tell us what’s in it.

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