How Jupiter Got Its Hot Spots

Jupiter is by far the largest planet dwelling in our Solar System. This fifth planet from our Star, the Sun, is more than 300 times the mass of our Earth, and twice as large as all of the other planets combined! In the lofty, whirling heights of Jupiter’s banded and colorful atmosphere, cloudless spots are so unusual that the larger ones have been given the appropriately descriptive name of hot spots! In March 2013, a team of planetary scientists announced that they discovered new evidence that these mysterious spots peppering Jupiter’s atmosphere are the result of what is termed a Rossby wave–a pattern seen in our own planet’s atmosphere and oceans. The scientists found that the wave responsible for Jupiter’s hot spots whirls up and down through the intriguing layers of Jupiter’s atmosphere.

Jupiter, the “King of Planets,” was appropriately named for the King of the Gods in Roman mythology (Greek Zeus), who ruled over the rather eccentric and colorful array of ever-squabbling gods and goddesses who dwelled on Mount Olympos. Jupiter has been known since prehistoric times as a brightly flitting dot of a “wandering star” that travels across the dark night sky of our planet.

Jupiter is about as large as it is possible for a gas giant planet to be and still be a gas giant planet. Gas giant planets, like Jupiter, may (or may not) contain relatively small solid surfaces secreted deep down beneath gigantic and very heavy envelopes of gas.

This extremely massive “King of Planets” is made up almost entirely of hydrogen and helium, and is very similar in its composition to a tiny, tiny star! However, despite the fact that it is the largest planet in our own Solar System, Jupiter does not possess the critical mass necessary for it to become a truly fiery stellar object, with a successfully ignited nuclear-fusing, searing-hot furnace in its core. The atmosphere of Jupiter is approximately 90% hydrogen, and the remaining 10% is almost entirely composed of helium laced with minute traces of other assorted gases. These gases form a system of layers lying one on top of another which extend downward. visit:- Because there is likely no solid ground, the surface of Jupiter is considered to be the point where the atmospheric pressure is precisely equivalent to that of our planet. At this point, the relentless and merciless pull of gravity downward is nearly two and a half times stronger than it is on Earth.

Any attempt to stand on Jupiter’s “surface” would be catastrophic. This is because it is merely another layer of gases. A wandering space probe, dispatched to investigate the weird interior of this gigantic and mysterious planet, would only float farther and farther downward toward the center, and merely find thick clouds of gas until it finally reached the core.

However, the nature of Jupiter’s core is swathed in bewitching mystery. Planetary scientists theorize that this hidden core is a searing-hot molten sphere composed of a liquid. However, some other researchers think that it may actually be a ball of solid rock that can weigh as much as 18 times that of our planet. The temperature at this mysterious core is estimated to be approximately 63,000 degrees Fahrenheit. This extremely hot and dense core may be encircled by a layer of metallic hydrogen, with yet another layer of molecular hydrogen positioned on top of it.

Scientific discussions of what may (or may not) compose the core of this very mysterious and alluring planet did not even begin until the late 1990s. This was when gravitational measurements revealed to scientists that the heart of the “King of Planets” was anywhere from 12 to 45 times the mass of our own Earth. Furthermore, just because Jupiter may once have had a heart, doesn’t mean that it still has one today. New evidence suggests that Jupiter’s heart may be in the process of melting!

Jupiter, like our Sun, is primarily composed of hydrogen and helium. However, unlike our Star, it is bereft of the requisite quantity of these gases to commence nuclear fusion–the process that sets a star, like our Sun, on fire. Jupiter would have to be at least 75 times more massive than it is to light up like a star!

Big Bright Bully

Using images derived from NASA’s exploratory Cassini Spacecraft, launched in 2004 primarily to investigate Saturn and its system of moons (especially the large moon Titan), planetary scientists have recently found evidence that hot spots whirling around up and down Jupiter’s system of layers were created by a Rossby wave. Rossby waves are enormous sweeping curves in high-altitude winds that play a major role in determining the weather.

“This is the first time anybody has closely tracked the shape of multiple hot spots over a period of time, which is the best way to appreciate the dynamic nature of these features,” said the study’s lead author, Dr. David Choi, in a March 14, 2013 NASA Jet Propulsion Laboratory (JPL) Press Release. Dr. Choi is a NASA Postdoctoral Fellow at NASA’s Goddard Space Flight Center located in Greenbelt, Maryland. The paper describing this research was first published online in the April 2013 issue of the journal Icarus.

Dr. Choi and his team created time-lapse movies derived from hundreds of images taken by Cassini during its closest flyby of Jupiter in late 2000, when it was on its way to the Saturn-system. The movies focus on a line of hot spots that are dancing between one of Jupiter’s dark belts and brilliant white zones, approximately 7 degrees north of the equator. The research studies the daily and weekly alterations in the shapes and sizes of the hot spots, each of which would cover an area exceeding that of the North American continent, on average. The study was conducted over a two-month period.

Much of what planetary scientists now know about these hot spots was derived from NASA’s Galileo mission. In 1995, Galileo released a probe into Jupiter’s atmosphere that dived deep into the secretive depths of one of the mysterious hot spots. This represents the first and only direct study of the Jovian atmosphere.

Galileo’s probe data and a handful of orbiter images hinted at the complex winds swirling around and through these hot spots, and raised questions about whether they fundamentally were waves, cyclones or something in between,” Dr. Ashwin Vasavada, a study co-author, commented in the March 14, 2013 JPL Press Release. Dr. Vasavada is at the JPL, which is located in Pasadena, California, and he was a member of the Cassini imaging team when it made its Jovian flyby. “Cassini’s fantastic movies now show the entire life cycle and evolution of hot spots in great detail,” he continued to note.

Hot spots are breaks in the clouds. As such, they provide peeks into a normally hidden layer of Jupiter’s multi-layered atmosphere. In fact, this probing sneak-peek may actually allow planetary scientists to make observations all the way down to the deep layer where water clouds can take shape on this gigantic, banded planet. In images, hot spots usually make their appearance as shadows. However, because the deeper layers of Jupiter are much more balmy than surface layers, hot spots shine brilliantly in the infrared where heat is sensed.

One theory bounced around by planetary scientists suggests that the hot spots form when enormous drafts of air plummet down into the atmosphere and get warmed up or dried out in the process. However, the great regularity of hot spots has caused other planetary scientists to speculate that there is an atmospheric wave meandering around that is the true culprit. Normally, eight to 10 hot spots line up, and they are surprisingly evenly spaced, with thick white plumes of cloud in between. This particular pattern could be caused by a wave pushing cold air down, breaking up clouds, and then carrying warm air upward. This process could explain the heavy cloud cover observed in the plumes. Computer simulations have strengthened this theory.

By teasing out numerous movements, such as the interactions of the hot spots with atmospheric vortices that whirl by, or wind gyres, or spiraling vortices that merge with the hot spots, the researchers were able to see that the movements of the hot spots fit the pattern of a Rossby wave in the Jovian atmosphere.

The culprit wave also ambles around the planet west to east. However, instead of wandering north and south, it jumps up and down in the atmosphere. The team of scientists estimates that this wave may rise and descend 15 to 30 miles in altitude.

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