Great Red Spot Archives

June 12, 2015December 23, 2015 by Bob King

UK Amateur Recreates the Great Red Spot’s Glory Days

Graphical comparison showing how Jupiter's Great Red Spot has shrunk in the past 125 years. Credit: Damian Peach

Maybe it’s too soon for a pity party, but the profound changes in the size and prominence of Jupiter’s Great Red Spot (GRS) in the past 100 years has me worried. After Saturn’s rings, Jupiter’s big bloody eye is one of astronomy’s most iconic sights.

This titanic hurricane-like storm has charmed earthlings since Giovanni Cassini first spotted it in the mid-1600s. Will our grandchildren turn their telescopes to Jove only to see a pale pink oval like so many others rolling around the planet’s South Tropical Zone?

Maybe.

Jupiter’s Great Red Spot is a cyclone larger than two Earths. (photomontage ©Michael Carroll) — Jupiter’s Great Red Spot is a cyclone that’s presently about 1.2 times as big as Earth. As recently as 1979, it was twice Earth’s diameter as illustrated here. Photomontage ©Michael Carroll

An inspired image prompted this sad train of thought. UK astrophotographer Damian Peach came up with an ideal way to depict how the GRS would look to us now if it we could see it as it was in 1890, 125 years ago. Those were the glory days for the “Eye of Jupiter” as Cassini was fond of calling it. With a diameter of 22,370 miles (36,000 km), the GRS spanned nearly three Earths wide. What a sight it must have been in nearly any telescope.

Peach compared measurements of the Spot in black and white photos taken at Lick Observatory in California in 1890-91 with a photo he took on April 13 this year. He then manipulated his April 13 data using the Lick photos and WINJUPOS (Jupiter feature measuring program) to carefully match the storm to its dimensions and appearance 125 years ago. Voila! Now we have a good idea of what we missed by being born too late.

“A century ago, it truly was deserving of its name!” wrote Peach.

Painting by Italian artist Donato Creti showing a telescopic view of Jupiter above a nighttime landscape. The Great Red Spot is clearly visible. — Painting by Italian artist Donato Creti showing a telescopic view of Jupiter in 1711 above a nighttime landscape. The Great Red Spot is clearly visible above center.

The shrinking of the Great Red Spot isn’t breaking news. You read about it here in Universe Today more than year ago. Before that, Jupiter observers had grumbled for years that the once-easy feature had become anemic and not nearly as obvious as once remembered. Astronomers have been following its downsizing since the 1930s.

These two photos, taken by Australian amateur astronomer Anthony Wesley, show the dramatic fading of Jupiter's South Equatorial Belt (SEB) from a year ago. The north belt remains dark and easy to see in a small telescope. The red oval is the Great Red Spot, a hurricane-like weather system some 2 1/2 times the size of the Earth. — Dramatic fading of Jupiter’s South Equatorial Belt (SEB) between 2009 and 2010. The belt has since returned to view. The Red Spot is also seen in both images. Credit: Anthony Wesley

That doesn’t mean it’s necessarily going away, though if it did — at least temporarily — it wouldn’t be the first time. The Spot vanished in the 1680s only to reappear in 1708. Like clouds and weather fronts that keeps things lively on Earth, Jupiter’s atmosphere constantly cooks up new surprises. The entire South Equatorial Belt, one of Jupiter’s two most prominent “stripes”, has taken a leave of absence at least 17 times since the invention of the telescope, the last in 2010.

Perhaps we should turn the question around? How has the Red Spot managed to last this long? Hurricanes on Earth have lifetimes measured in days, while this whirling vortex has been around for hundreds of years. Any number of things should have killed it: loss of energy through radiation of heat to outer space, or energy-sapping turbulence from nearby jet streams. But the Eye persists. So what keeps it alive? Astronomers think the storm might gain energy by devouring smaller vortices, those small white dots and ovals you see in high resolution photos of the planet. Vertical winds that transport hot and cold gases in and out of the Spot may also restore its vigor.

Just in case it disappears unexpectedly, take one last look this observing season. Jupiter’s currently getting lower in the western sky as it approaches Venus for its grand conjunction on June 30. Below are times (Central Daylight or CDT) when it crosses or transits the planet’s central meridian. The GRS will be easiest to see for a 2-hour interval starting an hour before the times shown. It’s located in the planet’s southern hemisphere just south of the prominent South Equatorial Belt. Add an hour for Eastern time; subtract one hour for Mountain and two hours for Pacific. A complete list of transit times can be found HERE.

* June 13 at 8:58 p.m.
* June 18 at 12:16 a.m.
* June 18 at 8:08 p.m.
* June 20 at 9:47 p.m.
* June 22 at 11:26 p.m.
* June 25 at 8:57 p.m.
* June 27 at 10:36 p.m.

March 17, 2015December 23, 2015 by Nancy Atkinson

Astrophoto: Hi-Res Stereo Pair of Jupiter and the GRS

A high resolution stereo pair of Jupiter and its Great Red Spot, captured on February 26, 2015. The two images were taken roughly five minutes apart. Credit and copyright: Damian Peach.

Cross your eyes and take a look at this image. If you’re lucky, you will be treated to a wonderfully clear 3-D view of Jupiter and its Great Red Spot, without the aid of a stereoscope. Or — if you haven’t quite mastered the art of viewing stereo pairs — you might end up with eyestrain.

Prolific astrophotographer Damian Peach took these two shots roughly five minutes apart — which makes them a great candidate for creating a stereo pair.

“Inspired by a suggestion from Dr. Brian May,” Peach told Universe Today via email, “this is the first time I’ve had two excellent quality sets of data so close in time with the GRS right in the centre to attempt this. I completely reprocessed the data for both images to keep a soft natural appearance and to closely match the colour between them as possible.”

Peach also said he measured the size of the GRS at 15,500km in width.

Still trying to view this as a 3-D image? Try this suggestion from Oxford University:

Hold a finger a short distance in front of your eyes and stare at it. In the background you should see two copies of the stereo pair, giving four views altogether. Move your finger away from you until you see the middle two of the four images come together. You should now see just three images in the background. Try to direct your attention slowly toward the middle image without moving your eyes, and it should gradually come into focus.

See more of Peach’s great astrophotography at his website.

November 12, 2014December 23, 2015 by Elizabeth Howell

Jupiter’s Great Red Spot Gets Its Color From Sunlight, Study Suggests

If it weren’t for the Sun, Jupiter’s Great Red Spot would be a much blander feature on the gas giant, a new study reveals. This stands apart from what most scientists think about why for why the spot looks so colorful: that there are features in the clouds that give it its distinctive shade.

The new data comes from observations with the Cassini spacecraft, combined with experiments in the lab. They conclude that the Red Spot’s immense height, combined with sunlight breaking apart the atmosphere there into certain chemicals, make the feature that red that is visible even in small telescopes.

“Our models suggest most of the Great Red Spot is actually pretty bland in color, beneath the upper cloud layer of reddish material,” said Kevin Baines, a Cassini team scientist based at NASA’s Jet Propulsion Laboratory in California, in a statement. “Under the reddish ‘sunburn’ the clouds are probably whitish or grayish.”

The lab experiments combined ammonia and acetylene gases (atmospheric components from Jupiter) with ultraviolet light (simulating what the Sun produces), which created a ruddy substance that matched observations made with the Cassini spacecraft back in 2000. They also tried breaking apart ammonium hydrosulfide, a common element in Jupiter’s high clouds, but the color produced was actually a bright green.

The Great Red Spot is a storm that has been raging on Jupiter since at least when telescopes were first used in the 1600s. Over the past few decades, its size has shrunk considerably –it’s now half of what historical measurements showed — but it is still much larger than Earth. Scientists are hoping the forthcoming Juno mission, which will arrive at Jupiter at 2016, will help learn more about what is going on.

Results were presented at the Division for Planetary Science of the American Astronomical Society’s annual meeting this week in Tucson, Arizona. A press release did not disclose publication plans or if the research is peer-reviewed.

Source: NASA

October 28, 2014January 15, 2019 by Matt Williams

Just In Time for Halloween: Jupiter Gets a Giant Cyclops Eye!

Jupiter's Great Red Spot and Ganymede's Shadow. Image Credit: NASA/ESA/A. Simon (Goddard Space Flight Center)

Halloween is just around the corner. And in what appears to be an act of cosmic convergence, Hubble captured a spooky image of Jupiter staring back at us with a cyclops eye!

While this is merely a convenient illusion caused by the passage of Ganymede in front of Jupiter – something it does on a regular basis – the timing and appearance are perfect.

Continue reading “Just In Time for Halloween: Jupiter Gets a Giant Cyclops Eye!”

March 25, 2014December 23, 2015 by Nancy Atkinson

New Storms on Jupiter Look Like Mickey Mouse

A full view of Jupiter on February 25, 2014 showing several features including three storms that in combination look like Mickey Mouse. Credit and copyright: Damian Peach.

We told you this was going to be a good season to observe Jupiter, and astrophotographers in the northern hemisphere have been making the most of this time of opposition where Jupiter has been riding high in the sky. What we didn’t know was that there was going to be a familiar face staring back at us.

A combination of three storms has been noted throughout this Jupiter observing season for its resemblance to Mickey Mouse’s face (at least in outline), and astrophotographer Damian Peach has captured some great images of these storms, along with the iconic Great Red Spot, its little brother Oval BA and other turbulence. Damian has also put together a stunning movie (below) showing about three hours of rotation of the king of the planets.

Damian explained the Mickey Mouse storms are two anticyclones (high pressure regions) that form the ears while a longer elongated cyclone (low pressure) forms the face.

The abundance of storms on Jupiter are a result of the planet’s dense atmosphere of hydrogen and helium and large gravitational field. Storms on this planet are likely the strongest in the Solar System.

Jupiter reached its most northern point for 2014 at a declination of +23.3 degrees on March 11, but it’s still easily visible since it is the brightest starlike object in the evening sky.

Jupiter's Great Red Spot and the 'Mickey Mouse' storms on February 25, 2014. Credit and copyright: Damian Peach. — Jupiter’s Great Red Spot and the ‘Mickey Mouse’ storms on February 25, 2014. Credit and copyright: Damian Peach.

More images of Jupiter on February 25, 2014, with these showing the Oval BA storm, with the Mickey Mouse storms peeking around the left side. Credit and copyright: Damian Peach.

As David Dickinson mentioned in his article on observing Jupiter, we’re also in the midst of a plane crossing, as the orbits of the Jovian moons appear edge-on to our line of sight throughout 2014 and into early 2015.

Damian captured this great transit of Europa earlier in February:

Check out more of Damian Peach’s work at his website.

February 4, 2014December 23, 2015 by Bob King

Will Jupiter’s Great Red Spot Turn into a Wee Red Dot?

Watch out! One day it may just go away. Jupiter’s most celebrated atmospheric beauty mark, the Great Red Spot (GRS), has been shrinking for years. When I was a kid in the ’60s peering through my Edmund 6-inch reflector, not only was the Spot decidedly red, but it was extremely easy to see. Back then it really did span three Earths. Not anymore.

Drawing of Jupiter on Nov. 1, 1880 by French artist and astronomer Etienne Trouvelot — Drawing of Jupiter made on Nov. 1, 1880 by French artist and astronomer Etienne Trouvelot showing transiting moon shadows and a much larger Great Red Spot.

In the 1880s the GRS resembled a huge blimp gliding high above white crystalline clouds of ammonia and spanned 40,000 km (25, 000 miles) across. You couldn’t miss it even in those small brass refractors that were the standard amateur observing gear back in the day. Nearly one hundred years later in 1979, the Spot’s north-south extent has remained virtually unchanged, but it’s girth had shrunk to 25,000 km (15,535 miles) or just shy of two Earth diameters. Recent work done by expert astrophotographer Damian Peach using the WINJUPOS program to precisely measure the GRS in high resolution photos over the past 10 years indicates a continued steady shrinkage:

2003 Feb – 18,420km (11,445 miles)

2005 Apr – 18,000km (11,184)

2010 Sep – 17,624km (10,951)

2013 Jan – 16,954km (10,534)

2013 Sep – 15,894km (9,876)

2013 Dec – 15,302km (9,508) = 1.2 Earth diameters

Voyager 1 Jupiter time lapse animation, a reprocessed high-resolution view. Enlarge to full screen to see the GRS rotation best. Credit: NASA / JPL / Bjorn Jonsson / Ian Regan

If these figures stand up to professional scrutiny, it make one wonder how long the spot will continue to be a planetary highlight. It also helps explain why it’s become rather difficult to see in smaller telescopes in recent years. Yes, it’s been paler than normal and that’s played a big part, but combine pallor with a hundred-plus years of downsizing and it’s no wonder beginning amateur astronomers often struggle to locate the Spot in smaller telescopes . This observing season the Spot has developed a more pronounced red color, but unless you know what to look for, you may miss it entirely unless the local atmospheric seeing is excellent.

Not only has the Spot been shrinking, its rotation period has been speeding up. Older references give the period of one rotation at 6 days. John Rogers (British Astronomical Assn.) published a 2012 paper on the evolution of the GRS and discovered that between 2006 to 2012 – the same time as the Spot has been steadily shrinking – its rotation period has spun up to 4 days. As it shrinks, the storm appears to be conserving angular momentum by spinning faster the same way an ice skater spins up when she pulls in her arms.

Drawings by Cassini of what is presumably the Great Red Spot in 1665 — Drawings by Cassini of what is presumably the Great Red Spot from 1665 to 1677. South is up. In size and shape it greatly resembles the current Red Spot. (From Amedee Guillemin’s “Le Ciel” 1877)

Rogers also estimated a max wind speed of 300 mph, up from about 250 mph in 2006. Despite its smaller girth, this Jovian hurricane’s winds pack more punch than ever. Even more fascinating, the Great Red Spot may have even disappeared altogether from 1713 to 1830 before reappearing in 1831 as a long, pale “hollow”. According to Rogers, no observations or sketches of that era mention it. Surely something so prominent wouldn’t be missed. This begs the question of what happened in 1831. Was the “hollow” the genesis of a brand new Red Spot unrelated to the one first seen by astronomer Giovanni Cassini in 1665? Or was it the resurgence of Cassini’s Spot?

4-frame animation spans 24 Jovian days, or about 10 Earth days. The passage of time is accelerated by a factor of 600,000. Credit: NASA — 14-frame animation showing the circulation of Jupiter’s atmosphere spans 24 Jovian days, or about 10 Earth days. The passage of time is accelerated by a factor of 600,000. Credit: Voyager 1 / NASA

Clearly, the GRS waxes and wanes but exactly what makes it persist? By all accounts, it should have dissipated after just a few decades in Jupiter’s turbulent environment, but a new model developed by Pedram Hassanzadeh, a postdoctoral fellow at Harvard University, and Philip Marcus, a professor of fluid dynamics at the University of California-Berkeley, may help to explain its longevity. At least three factors appear to be at play:

* Jupiter has no land masses. Once a large storm forms, it can sustain itself for much longer than a hurricane on Earth, which plays itself out soon after making landfall.

* Eat or be eaten: A large vortex or whirlpool like the GRS can merge with and absorb energy from numerous smaller vortices carried along by the jet streams.

* In the Hassanzadeh and Marcus model, as the storm loses energy, it’s rejuvenated by vertical winds that transport hot and cold gases in and out of the Spot, restoring its energy. Their model also predicts radial or converging winds within the Spot that suck air from neighboring jet streams toward its center. The energy gained sustains the GRS.

Feb. 1 photo of Oval BA, a.k.a. Red Spot Jr. It's the first significant new red s[pt ever observed on Jupiter and located at longitude 332 degrees (Sys. II) The spot about half the width of the more familiar Great Red Spot. Credit: Christopher Go — Feb. 1 photo of Oval BA, a.k.a. Red Spot Jr. It’s the first significant new red spot ever observed on Jupiter and located at longitude 332 degrees (Sys. II) The spot about half the width of the more familiar Great Red Spot. Credit: Christopher Go

If the shrinkage continues, “Great” may soon have to be dropped from the Red Spot’s title. In the meantime, Oval BA (nicknamed Red Spot Jr.) and about half the size of the GRS, waits in the wings. Located along the edge of the South Temperate Belt on the opposite side of the planet from the GRS, Oval BA formed from the merger of three smaller white ovals between 1998 and 2ooo. Will it give the hallowed storm a run for its money? We’ll be watching.

Time-lapse of Jupiter’s atmospheric motions centered on the Great Red Spot photographed by Paolo Porcellana. Each cylindrical/spherical map of the planet is a mosaic of 4-6 pictures made with 11 and 14-inch telescopes.

December 23, 2013December 23, 2015 by David Dickinson

‘Tis the Season to Spot Jupiter: A Guide to the 2014 Opposition

Jupiter+moon imaged recently by Paul Cotton (@paultbird66) of Lincolnshire, England. Used with permission.

Lovers of planetary action rejoice; the king of the planets is returning to the evening skies.

One of the very first notable astronomical events for 2014 occurs on January 5^th, when the planet Jupiter reaches opposition. You can already catch site of Jove in late December, rising in the east about an hour after local sunset. And while Venus will be dropping faster than the ball in Times Square on New Year’s Eve to the west in early 2014, Jupiter will begin to dominate the evening planetary action.

Orbiting the Sun once every 11.9 years, oppositions of Jupiter occur about once every 13 months or about 400 days, as the speedy Earth overtakes the gas giant on the inside track. This means that successive oppositions of the planet move roughly one astronomical constellation eastward. In fact, this year’s opposition is it’s northernmost in 12 years, occurring in the constellation Gemini. “Opposition” means that an outer planet is rising “opposite” to the setting Sun. As this opposition of Jupiter occurs just weeks after the southward solstice, Jupiter now lies in the direction that the Sun will occupy six months from now during the June Solstice.

This all means that Jupiter will ride high in the sky for northern hemisphere observers towards local midnight, a boon for astrophotographers looking to catch the planet high in the sky and out of the low horizon murk.

Jupiter will reach its most northern point for 2014 at a declination of +23.3 degrees on March 11^th.

Jupiter also “skipped” 2013, in the sense that it was an “oppositionless year” for the giant world, as said 13 month span fell juuusst right, first on December 2^nd, 2012 and then on January 5^th, 2014. The next opposition of Jupiter will occur on… you guessed it… February 6^th, 2015. The last year missing an opposition of Jupiter was 2001.

Jupiter and Io (arrowed) as imaged on the evening of December 22nd, 2013 by the author.

The exact timing of Jupiter’s opposition to the Sun in right ascension occurs at 21:00 UT/4:00 PM EST on January 5^th. Its closest approach to Earth, however, arrives 27 hours prior, owing to a slight outward curvature of the approach of the two worlds. Jupiter will then lie about 4.21 astronomical units (AUs) or 629 million kilometres distant. This is just about down the middle of how close it can pass; Jupiter was just under 4 AUs distant in September 2010, and can pass almost 4.5 AUs from Earth, as happened in April 2005.

Jupiter also reaches a maximum brightness of magnitude -2.7 at opposition in 2014 and presents a disk 46.8” arc seconds wide. The coming month also provides a great chance to catch Jupiter in the daytime sky just before sunset, when the waxing gibbous Moon passes 4.9 degrees south of the planet on the evening of January 14^th.

The Moon and Jupiter on the evening of January 14th shortly before sunset. (Created by the Author using Stellarium).

The very first thing you’ll notice looking at Jupiter, even at low power with binoculars or a telescope, is it retinue of moons. Though the planet has 67 discovered moons and counting, only the four large Galilean moons of Io, Europa, Ganymede and Callisto are readily apparent in a telescope. It’s fun to see orbital mechanics in action and watch them from night to night as they change position, just as Galileo first did over four centuries ago. This provided him with evidence that there is much more to universe than meets the eye, though we can consider ourselves fortunate that his proposal to name them the “Medician Moons” after his Medici benefactors was never widely adopted.

Crank up the magnification, and you’ll notice the large twin stripes of the northern and southern equatorial cloud belts crossing the disk of Jupiter. While the northern belt is stable, the southern belt has been known to submerge and disappear from view about every decade or so, as last happened in 2009-2010. You’ll also notice the Great Red Spot, a massive storm system over three times larger than the Earth that has been tracked by astronomers since it was recorded by Samuel Schwabe in 1831. The planet has the fastest rotation of any world in our solar system at 9.9 hours, and you’ll notice this swift rotation tracking Jupiter over the course of a single evening.

Transits and occultations of Jupiter’s moons are also always interesting to watch. The variation in the timing of these events at differing distances led Danish astronomer Ole Rømer to make the first attempts at measuring the speed of light in 1676.

Europa just beginning to cast a shadow off to one side shortly after opposition on January 8th at 7:30PM EST. (Created by the author using Stellarium). — Europa just beginning to cast a shadow off to one side shortly after opposition on January 8th at 7:30 PM EST. (Created by the author using Starry Night).

It’s interesting to note that Jupiter and its moons cast a shadow nearly straight back from our line of sight around opposition. You can see this change as the planet heads towards quadrature on April 1^st, 2014 and Jupiter and its moons cast shadows off to one side. We’re also in the midst of a plane crossing, as the orbits of the Jovian moons appear edge-on to our line of sight in 2014 headed into early 2015. The outermost Jovian moon Callisto began a series of transits in 2013 and will continue to do so through 2014.

This is a great time to begin following all of the Jovian action, as we head into another exciting year of astronomy!

March 16, 2010January 22, 2016 by Nancy Atkinson

New Images Unlock Secrets of Jupiter’s Red Spot

New thermal images from powerful ground-based telescopes show swirls of warmer air and cooler regions never seen before within Jupiter's Great Red Spot. Image credit: NASA/JPL/ESO and NASA/ESA/GSFC

It’s difficult enough to track the weather on Earth, but with new thermal images of Jupiter’s Great Red Spot, scientists now have the first detailed interior weather map of a giant storm system on another planet. “This is our first detailed look inside the biggest storm of the solar system,” said Glenn Orton, a senior research scientist at NASA’s Jet Propulsion Laboratory. “We once thought the Great Red Spot was a plain old oval without much structure, but these new results show that it is, in fact, extremely complicated.”
Continue reading “New Images Unlock Secrets of Jupiter’s Red Spot”

June 16, 2008May 2, 2017 by Matt Williams

What are Temperatures Like on Jupiter?

A true-color image of Jupiter taken by the Cassini spacecraft. The Galilean moon Europa casts a shadow on the planet's cloud tops. Credit: NASA/JPL/University of Arizona

Jupiter, which takes its name from the father of the gods in ancient Roman mythology, is the largest planet in our Solar System. It also has the most moon’s of any solar planet – with 50 accounted for and another 17 awaiting confirmation. It has the most intense surface activity, with storms up to 600 km/h occurring in certain areas, and a persistent anticyclonic storm that is even larger than planet Earth.

And when it comes to temperature, Jupiter maintains this reputation for extremity, ranging from extreme cold to extreme hot. But since the planet has no surface to speak of, being a gas giant, it’s temperature cannot be accurately measured in one place – and varies greatly between its upper atmosphere and core.

Currently, scientists do not have exact numbers for the what temperatures are like within the planet, and measuring closer to the interior is difficult, given the extreme pressure of the planet’s atmosphere. However, scientists have obtained readings on what the temperature is at the upper edge of the cloud cover: approximately -145 degrees C.

Because of this extremely cold temperature, the atmosphere at this level is composed primarily of ammonia crystals and possibly ammonium hydrosulfide – another crystallized solid that can only exist where conditions are cold enough.

However, if one were to descend a little deeper into the atmosphere, the pressure would increases to a point where it is ten times what it is here on Earth. At this altitude, the temperature is thought to increase to a comfortable 21 °C, the equivalent to what we call “room temperature” here on Earth.

Descend further and the hydrogen in the atmosphere becomes hot enough to turn into a liquid and the temperature is thought to be over 9,700 C. Meanwhile, at the core of the planet, which is believed to be composed of rock and even metallic hydrogen, the temperature may reach as high as 35,700°C – hotter than even the surface of the Sun.

Interestingly enough, it may be this very temperature differential that leads to the intense storms that have been observed on Jupiter. Here on Earth, storms are generated by cool air mixing with warm air. Scientists believe the same holds true on Jupiter.

A close-up of Jupiter's great red spot. Credit: NASA/JPL-Caltech/ Space Science Institute — *A close-up of Jupiter’s great red spot, an anticyclonic storm that is larger than Earth. Credit: NASA/JPL-Caltech/ Space Science Institute*

One difference is that the jet streams that drive storms and winds on Earth are caused by the Sun heating the atmosphere. On Jupiter it seems that the jet streams are driven by the planets’ own heat, which are the result of its intense atmospheric pressure and gravity.

During its orbit around the planet, the Galileo spacecraft observed winds in excess of 600 kph using a probe it deployed into the upper atmosphere. However, even at a distance, Jupiter’s massive storms can be seen to be humungous in nature, with some having been observed to grow to more than 2000 km in diameter in a single day.

And by far, the greatest of Jupiter’s storms is known as the Great Red Spot, a persistent anticyclonic storm that has been raging for hundreds of years. At 24–40,000 km in diameter and 12–14,000 km in height, it is the largest storm in our Solar System. In fact, it is so big that Earth could fit inside it four to seven times over.

Given its size, internal heat, pressure, and the prevalence of hydrogen in its composition, there are some who wonder if Jupiter could collapse under its own mass and trigger a fusion reaction, becoming a second star in our Solar System. There are a few reasons why this has not happened, much to the chagrin of science fiction fans everywhere!

*This cut-away illustrates a model of the interior of Jupiter, with a rocky core overlaid by a deep layer of liquid metallic hydrogen. Credit: Kelvinsong/Wikimedia Commons*

For starters, despite its mass, gravity and the intense heat it is believed to generate near its core, Jupiter is not nearly massive or hot enough to trigger a nuclear reaction. In terms of the former, Jupiter would have to multiply its current mass by a factor of 80 in order to become massive enough to ignite a fusion reaction.

With that amount of mass, Jupiter would experience what is known as gravitational compression (i.e. it would collapse in on itself) and become hot enough to fuse hydrogen into helium. That is not going to happen any time soon since, outside of the Sun, there isn’t even that much available mass in our Solar System.

Of course, others have expressed concern about the planet being “ignited” by a meteorite or a probe crashing into it – as the Galileo probe was back in 2003. Here too, the right conditions simply don’t exist (mercifully) for Jupiter to become a massive fireball.

While hydrogen is combustible, Jupiter’s atmosphere could not be set aflame without sufficient oxygen for it to burn in. Since no oxygen exists in the atmosphere, there is no chance of igniting the hydrogen, accidentally or otherwise, and turning the planet into a tiny star.

Scientists are striving to better understand the temperature of Jupiter in hopes that they will eventually be able to understand the planet itself. The Galileo probe helped and data from New Horizons went even further. NASA and other space agencies are planning future missions that should bring new data to light.

To learn more about Jupiter, check out this article on how weather storms on Jupiter form quickly. Here’s Hubblesite’s News Releases about Jupiter, and NASA’s Solar System Explorer.

We’ve also recorded an entire show just on Jupiter for Astronomy Cast. Listen to it here, Episode 56: Jupiter, and Episode 57: Jupiter’s Moons.

Sources:
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jupiter&Display=OverviewLong
http://www.jpl.nasa.gov/news/news.cfm?release=2008-013