New study suggests Europa (the moon of Jupiter, one of many) shines (Glows) at night but in kinda different way. It is also called glow in dark moon. We’ll be going to those details but first moving to the basics of this moon. Europa is sixth largest moon and it is fifteenth largest object in our solar system. It is 4.5 billion years old. It is made of silicate rock and icy crust. The surface temperature at equator is -160o C and at the poles it is -220o C.
Europa is smaller than Earth’s moon and has a thin atmosphere which is composed of oxygen. While the surface of Europa is smooth and solid, the surface of Earth’s Moon is bumpy. Europa is tidally locked so the same side faces Jupiter all the time. The Hubble Telescope also detected aqueous vapor on Europa. You must be curious about the lines on the surface of Europa. They are nothing but cracks within the icy crust of the moon. These cracks are formed by the gravitational pull of Jupiter. These cracks are thousands of kilometres long. The above image is nothing but art illustration. In actual it may glow in different way.
The ice on the night side of moon Europa glows. This type of glow is not seen elsewhere in the solar system. So, this thing was observed when a lab based experiment was carried out. And the obtained results showed that the ice emits a unique glow depending on the minerals present in the ice. Jupiter has a strong magnetic field and when this so called glow in dark moon passes through this field, on its way the surface of the moon is bombarded with high energy photons, ions and electrons. In lab, the researchers carried out this experiment by firing beams of electrons at the sample of ice to simulate the radiation, they observed that ice emitted a faint glow.
As these electrons and photons interact with the moons salt, this could result in triggering the complex physical and chemical process. These electrons enter the ice and react with the material and this results in releasing the energy in the form of light. In the experiment, the results showed that the ice containing the elements like hydrous magnesium sulfate glowed more as compared to the ice containing sodium chloride and sodium carbonate.
Now, the scientists can determine chemical composition of ice by observing the glow and can determine the concentration of these elements. The scientists said the color glow may range greenish to bluish to whitish. It totally depends on the composition. Europa receives high dose of radiation about 5.4 Sv (Sievert) per day. If humans are exposed to this radiation for one day, then within 30 days more than half of the population exposed to the radiation will die.
NASA is planning a Europa Clipper Mission which will launch in 2025. The Clipper probe will carry instruments which will help to observe whether life could exits under the surface of Europa. It will also help to study other moons of Jupiter.