Jupiters Great Red Spot

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Jupiter is the fifth planet in our solar system.  It is a gas giant, and considering it is the largest planet in our system, giant is an appropriate term.  Galileo, the famous astronomer, is given credit for first viewing and recording the existence of the planet and its four largest moons in 1610.  And he gave the newly discovered planet its name, after the Roman god of lightning.  It was then that Galileo first observed the most unique feature of the planet: the Great Red Spot of Jupiter.  

Jupiter's Great Red Spot has been studied both from Earth and by orbital probes that beamed data and amazing pictures back to Earth.  And yet for all of this information, the more we learn about Jupiter, the more questions we have to ask.  The Great Red Spot has been one of the constants in the universe.  It has been present in the skies of Jupiter for more than four hundred years, since Galeleo first observed it through his telescope, and surely for longer than that.  But what is it?  

To start with, there are a few facts about the Great Red Spot of which the scientific community agree upon.  The Spot is actually a storm consisting of gaseous clouds in constant turmoil.   It has a counterclockwise rotation, like the hurricanes we have on Earth.  The Spot is so big from edge to edge that the planet Earth could fit inside it twice, side by side. 

But beyond these facts, there is little else about this mysterious extra-terrestrial storm that is completely understood.  For instance, it has shrunk in size over the centuries, from when it was first discovered until now.  But the reason for this remains unknown.  Even its coloration is not always the same, but is rather a shifting and changing collection of different shades of red.

Scientists and astronomers have tried to unravel the riddles that Jupiter and its Great Red Spot present.  It is almost certain that the elements found on Jupiter will be some of the same found on Earth.  Computer models have been used to test known elements in an attempt to reproduce the same effect found in the Great Red Spot.  One possible explanation for what is happening to create the Spot is that the color is created by certain specific elements of phosphorous.  Another theory that has been suggested says sulfurous molecules are being lifted up by the storm, and once exposed to sunlight in the atmosphere, the molecules break apart and basically “paint” the area the familiar reddish-brown that we see.  These are theories that will remain unproven until a probe can be sent down into the atmosphere of Jupiter to collect samples and return them to Earth.  At nearly 89,000 miles from Earth, it will be generations before astronauts go to Jupiter in person.

So far, thermal imaging of the Great Red Spot is the best data we have obtained.  These images have revealed variations in temperature and weather patterns.  Although the storm itself is a cold storm, the darkest red part turns out to be a few degrees warmer than the rest, minus 250 degrees Fahrenheit versus a usual minus 256 degrees for the rest of the storm.  Scientists believe that even this slight variation in temperature creates part of the internal dynamics of this ages-old storm.  The difference in temperatures acts as a heat sink, pulling the relatively hotter and colder gases around and around as they attempt to reach equilibrium, producing the spinning motion that can be observed in the Spot.

While the Great Red Spot may seem relatively stable, there is evidence to show it may not be that way forever.  Sometime in 2010, a shocking discovery was made by an ameteur astronomer studying Jupiter.  One of the two wide stripes circling the planet nearest its equator has disappeared.  This one equatorial belts, as they were known, is now gone.  It may have simply dissipated into the atmosphere, or it may be an indicator of more volatile forces at work on the planet.  Either way it proves that the atmosphere of Jupiter is in a state of fluxuation.

According to NASA, the Great Red Spot measured 40,000 kilometers across just a century ago.  Now, it is measured at about half that distance.  Is this a result of better data collection devices taking more accurate measurements?  Or will there come a day when the Great Red Spot is only a notation in astronomy books, a curious phenomena of our solar system that disappeared before it could be fully explained?


National Geographic

University of Tennessee Department of Education

Universe Today

More about this author: Shawn Wells

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