User:Maccrouch12/Atmosphere of Europa

Overview:
The atmosphere of Europa can be categorized as a thin, tenuous atmosphere primarily composed of oxygen and trace amounts of water vapor. However, this quantity of oxygen is produced in a non-biological manner. Given that Europa’s surface is icy, and subsequently very cold; as ultraviolet light mixed with charged particles come into contact with its surface, water vapor is created. As the water vapor instantaneously rises, it is fragmented into oxygen and hydrogen. As it continues to rise, the hydrogen is light enough to pass through the surface gravity of the atmosphere leaving behind only oxygen. This is a direct effect of radiolysis. This accumulated oxygen atmosphere can get to a height of 125 miles above the surface of Europa. Europa is one of the only moons in our solar system with a quantifiable atmosphere, next to Titan, Lo, and Triton. Europa is also one of the three formations, among planets and moons, to contain oxygen within its atmosphere.

Europa is also considered to be geologically active due to the constant release of hydrogen-oxygen mixture into space. As a result of the moon’s particle venting, the atmosphere requires continuous replenishment. Europa also contains a small magnetosphere (approximately 25% of Ganymede’s). However, this magnetosphere varies in size as Europa orbits through Jupiter's magnetic field. This confirms that a conductive element, such as a large ocean, likely lies below its icy surface. As multiple studies have been conducted over Europa’s atmosphere, several findings conclude that not all oxygen molecules are released into the atmosphere. This unknown percentage of oxygen may be absorbed into the surface and sink into the subsurface body of water-salt constituents.

Through the slow release of oxygen and hydrogen, a neutral torus around Europa’s orbit plane is formed. This torus was officially confirmed using Energetic Neutral Atom (ENA) imaging. Europa’s torus ionizes through the process of neutral particles exchanging electrons with its charged particles. Since Europa’s magnetic field rotates faster than its orbit velocity, these ions are left in the path of its magnetic field trajectory, forming a plasma. It has been theorized that these ions are responsible for the plasma within Jupiter's magnetosphere.

Discovery:
The atmosphere of Europa was first discovered in 1995 by the Goddard High Resolution Spectrograph of the Hubble telescope. This observation was then confirmed in 1997 by the Galileo probe which was built by Hughes Aircraft Company and operated by NASA. The Galileo probe flew only three miles above the estimated maximum atmospheric line (128 miles from Europa's surface), but then directed course to collide with Jupiter's atmosphere in order to prevent impact with Europa. It has been speculated that there will be several more future missions to Europa in hopes to further study the atmosphere, chemical composition, and possibility of extraterrestrial life.

Weather and Climate:
Despite the presence of a gas torus, Europa has no weather producing clouds. As a whole, Europa has no wind, precipitation, or presence of sky color due to the low presence of gravity. Europa’s gravity is approximately 13% of earths. The temperature on Europa varies from -260 degrees Fahrenheit at the equatorial line, to -370 degrees Fahrenheit at either of its poles.

Studies have also concluded  that Europa’s ocean would have been rather acidic at first, with large concentrations of sulfate, calcium, and carbon dioxide. But over the course of 4.5 billion years, it became full of  chloride, thus resembling our 1.94% chloride oceans on Earth.