Astronomical Volcanology is the study of volcanoes in outer space. It explains mysteries regarding the geo structure of a planet, the internal geothermal activity of the planet, and the outer geography of the planet. Astronomical Volcanology is also essential to the field of Planetary Meteorology. Millions of trillions of years ago, volcanoes formed our atmosphere, and can do this on other planets too! It helps us to understand our own lovely planet by providing information about the other celestial bodies in the solar system, thus helping us to better understand our own. And finally, it gives us a map of a planet’s history. For example, the region around Olympus Mons, on Mars, is only approximately 100 million years old. This is only 2 % the approximate age of Mars, so we can hypothesize that Olympus Mons erupted for 98% of Mars’ history. This field of science is extremely vital to studying the history of the universe and its contents.
The volcanoes in space are primarily researched on the planets Mercury, Venus and Mars, and also on the moons Io (orbiting Jupiter) and Titan (orbiting Saturn). Orbiting satellites, planetary probes and landing rovers allow scientists to gather firsthand data about these marvelous and mysterious mountains.
On Mercury, the Messenger spacecraft orbited the planet and gathered data on the far side, that is, the side never before studied, of Mercury. The Messenger spacecraft found evidence of old volcanoes on the surface of Mercury. The evidence included rifts along the surface of the planet, craters with traces of lava, and old mountains resembling those of active volcanoes on Earth. Scientists believe the rifts were caused by volcanoes erupting while the planet was still young and volcanically active. As the planet cooled from the outside in, the surface shrank and crunched, causing the rifts. On Earth, this is what was once believed to have shaped mountains, before the discovery of plate tectonics. In other findings on Mercury, scientists discovered craters with what appears to be solidified lava. The theory behind this is that after the meteorite crashed into the planet, lava oozed out. These weakened spots became prone to more internal pressure, forming new volcanoes. This is important because it shows us how planets form so close to stars, helping us learn about the planets in other solar systems.
Venus has more volcanoes than any other planet in our solar system. Scientists have discovered over 1600 major volcanoes or volcanic features, and an unknown number of minor volcanoes. The minor volcanoes have not been counted, but they have been estimated to be between 100,000 and 1,000,000! Most appear to be extinct, (meaning not erupting anymore), shield volcanoes, but there are also a number of extinct cone volcanoes. Although no active volcanoes have been discovered, knowledge of Venus’ surface is very limited, and scientists are open to the possibility of an active volcano on Venus, which is starting to seem quite likely. Venus’ volcanoes are interesting because they appear limited in eruptive styles. The surface only shows signs of lava flows, no explosions. This is possibly because of the high atmospheric pressure of Venus; the pressure required for an explosion is much greater than that required on Earth. Distinctive of Venus is its thick, heavy atmosphere, which is comprised mainly of CO2, the gas primarily released from a volcano on Earth. This atmosphere also shows evidence of volcanic presence on Venus; the volcanoes would have released heavy gases into the atmosphere, making it thick and heavy.
Mars is unique among the planets because it is home to our solar system’s largest known volcano, Olympus Mons. Olympus Mons is a shield volcano, over three times as tall as Mount Everest and as wide as the entire Hawaiian Island chains. It is a dome volcano; however, it is nearly entirely flat on the top, with a gentle slope of between 2o and 5o. Mars is also home to many other large volcanoes, most of them up to two and one half times larger than the volcanoes found on Earth. These volcanoes are all dome volcanoes, with a flat top. Scientists are unsure why Mars’ volcanoes are characteristically flat. Interestingly enough, Mars shows no signs of ever having active plate tectonics. The large mountain chains on Earth, usually occurring at the sight of a plate tectonic junction, do not occur on Mars, indicating that all of the volcanoes are hotspot volcanoes, that is, volcanoes caused by extreme heat and pressure in one location under the planet surface, rather than as a result of pressure caused by friction at fault lines, (where tectonic plates meet). Interestingly enough, Mars is believed to possibly be still volcanically active. Mars is hit by meteorites very often, and when an area of the planet appears smooth, geologists believe that it is because the area has been “resurfaced” recently by lava flowing over the area and cooling. Several such areas have been discovered on Mars, indicating that it may still be an active planet. The reason that we have not recorded any volcanic activity is likely because, while we have many probes and rovers on Mars, and spacecraft orbiting above, we are still not able to observe the entire surface at any given time. Given the ratio of planetary surface by surface area measured at the same time, it is actually very unlikely that we can observe a volcanic eruption on Mars, and are reduced to the second best option of making frequent observations to monitor changes.
On Io, the volcanoes are more geyser like, that is, rather than erupting molten rock, they erupt more along the lines of steam and gases. What's interesting about this is that it shows that Io has a geothermically stable structure, (the stuff inside it doesn't move much and doesn't exert a lot of pressure on the surface), but it does contain a lot of gases, also, it may even contain water vapor. And the volcanoes on Titan are now believed to erupt ice. That any volcanoes could erupt ice is scientifically astounding, since there is so much pressure and heat from friction in the volcano, and water would be erupted as steam, not ice, so Planetary Geologists are really trying to understand how this phenomenon is possible.
These few examples show how Astronomical Volcanology is important to science, and how it aids us in learning and exploring other planets. From studying Mercury, orbiting so close to a star, to Venus, with its thick, poisonous atmosphere, to Mars, which, though seeming so small, contains our solar system’s largest volcanoes, to Io and Titan, where we are only beginning to grasp the scientific data shown by their volcanoes, Astronomical Volcanology is always teaching us more about the history of our universe and the story of its many hidden mysteries.
Well, I hope you enjoyed learning about Astronomical Volcanology. Isn't is simply fascinating?! Now you know why it's going to be my major.
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