Peering into Jupiter's red eye

By Phil Plait | March 24, 2010 8:00 am

Jupiter’s Great Red Spot is perhaps its most iconic feature. It’s a vast storm, a bloody-colored hurricane that is at least four centuries old, and larger in size than several Earths. It can be seen easily even in a small telescope, and is one of the most studied features in the solar system.

Yet for all that, it’s still poorly understood. How has it lasted so long? What is going on inside of it? How did it form in the first place?

New observations using the Very Large Telescope (together with data from the Gemini, Subaru, and IRTF observatories) have taken us a step closer to finding the answers:


Cooooool. On top is an infrared view of the Spot (as well as its little brother, Oval BA, on the left) from the VLT taken in 2008, and on bottom, for comparison, is the same view from Hubble taken just days earlier. The VLT image was taken at a wavelength of 10.8 microns, about 14 times the wavelength our eye can see. Objects at just about the freezing point of water emit IR at that wavelength. On Jupiter, the atmosphere at a pressure about half of Earth’s pressure at sea level emits at that temperature and wavelength.

What these images show is how Jupiter’s atmosphere circulates up and down in the Spot. The core of the Spot, which appears red to our eye, is warm, and dark lanes are where the gas is being drawn down into Jupiter’s depths. Because the center is warmer — by just a few degrees — it provides an upwelling in the middle of the Spot. This upwelling creates a weak clockwise flow of air, despite the storm’s general counter-clockwise rotation.

More importantly, these observations link the color of the Spot to temperature, even if the exact mechanism for this link is unknown. But any clues we can find will help us understand this incredible hurricane bigger than some planets. Mind you, studying them on Jupiter gives us insight into how storms behave on Earth as well. Scientific observations thrive on diversity, on comparing one set of conditions to another, and seeing how the outcome changes.

Jupiter is vastly different than Earth, but by gazing at it we gaze back at ourselves. That’s the way science works.


Comments (15)

  1. Thameron

    How exactly does studying storms on Jupiter give us more or better information about Earthly storms than studying those same Earthly storms in greater depth (which scientists can doubtless do since we can get inside them here)? Do you have an example of where studying other planetary atmospheres revealed some insight we could not have attained here?

  2. Ken

    Hurricanes on Earth are cyclonic, and their rotation depends on which hemisphere they are in: counterclockwise in the North, clockwise in the South. The Great Red Spot isn’t doing that – it is spinning COUNTERclockwise in the southern hemisphere.

    A great article to read about the GRS, quoting Frank Hanou of Astronomy magazine, is:

    To me, studying storms on Jupiter DOES give us better information about earthly storms, because it can provide data on how storms can occur abnormally…or “outside” the reigns of normal storm growth, progression, and death (here on Earth). We’ve all seen the sci-fi flicks with huge storms that come ripping across the northern USA and send us into another Ice Age. If we one day undestood what caused the GRS and it’s smaller friends to form, and LIVE, for so long, it could teach us that having those same meteorological circumstances on earth could create a similar superstorm, although it might not live as long.
    I believe studying these DOES have relevance, it just might not be what you expect.

  3. Matt T

    This just in: The Bad Astronomer has a little brother, and his name is Oval. Wait…Oval? What kind of name is that?!

  4. Gary Ansorge

    Seems there must be a big heat source beneath the BRS(Big Red Spot). Maybe a slowly decaying “small” black hole. Wouldn’t THAT be a hoot?

    I wonder how long we’d see heat rising from a major impact event on Jupiter? Perhaps an impact from a planet sized object a few centuries ago could provide the residual energy to drive this storm.

    So many speculations. So much fun.

    I’ve been fascinated by the BRS since I first read of it, a half century ago.

    GAry 7

  5. Messier Tidy Upper

    Awesome image & one of the wonders of our solar system.
    Thanks BA & VLT for bringing us this. :-)

    @3. Gary Ansorge Says:

    Seems there must be a big heat source beneath the BRS(Big Red Spot). Maybe a slowly decaying “small” black hole. Wouldn’t THAT be a hoot?

    Or a black monolith or two … hundred … plus! 😉

    Hey, it is 2010 after all! 😉

    (For both people here who don’t already know what I’m referring to, see : )

  6. @Thameron

    I should preface this by saying I’m not immediately familiar with how this research is used, but I’m making some reasonable assumptions.

    Storms and other chaotic phenomena are difficult enough to understand by direct observation due to the large number of variables involved and the inability to conduct experiments. (How do you make a storm?)

    Jupiter has (at very least) a very different atmosphere and I’d imagine that by looking at Jupiter’s weather patterns, we can start to create more general sets of rules for these phenomena that are not affected by factors that may be unique to earth.

    This is similar to how looking at Venus has helped us to better understand global warming and the greenhouse effect here on earth.

  7. Chris A.

    Umm, minor quibble Phil: Hurricanes are cyclones (i.e. centered on regions of low pressure), while the GRS is an anticyclone (centered on a region of high pressure). Thus it rotates in the opposite direction compared to a cyclone in the same hemisphere.

  8. Brian T.


    Observations of Venus’s atmosphere allowed us to start understanding the effect of greenhouse gases and how it relates to our own atmosphere. Seeing a runaway greenhouse effect on Venus gave us exactly what you were asking about, “an example of where studying other planetary atmospheres revealed some insight we could not have attained here”.

  9. P@J

    …so at the level of Jupiter’s atmosphere where pressure is 1/2 that of earth’s surface, the temperature is just above the melting point of water? Why don’t we have weather balloons there? Why don’t we have dirigibles there?

  10. QuietDesperation

    It’s watching me…

  11. Thameron

    Did they not know about the heat trapping abilities of Carbon Dioxide prior to measuring the effects in Venus’ atmosphere? That isn’t a snide question. I am not a historian of atmospheric science and genuinely do not know. It just seems like such a basic fact would have been long known by chemists before the era of space travel.

    Here is the problem I find in using Jupiter observations to tell us anything we don’t know or can’t find out here. On Earth we can have an abundance of data points to plug into our model which simply cannot be duplicated on Jupiter. We can measure temperature, humidity, pressure, wind speed and direction from multiple locations and at multiple altitudes from inside the storm as well as looking at the storm from space in various wavelengths. By comparison the data from Jupiter will be much more limited. We don’t have probes at various heights in Jupiter’s atmosphere not to mention the different chemical composition of the clouds. There are no observations that we can do of the Great Red Spot that we can’t do here on terrestrial storms and lots we can do here that cannot be done for that storm. I am sure that gathering Red Spot data is useful for constructing a model of Jovian weather, but I am not seeing how that transfers to an atmosphere driven by different factors (like surface heating and cooling and movement of water and water vapor). Minus an example of such a transfer the utility of these observations for terrestrial weather modeling will doubtless continue to escape me.

    It could also be that all this ‘science’ is just a distraction and the Great Red Spot is simply the latest location of Sauron’s eye (although you’d think that spinning around like that would make him dizzy).

  12. Navneeth

    This upwelling creates a weak clockwise flow of air…

    Air — on Jupiter?

  13. m5

    Yes. Jovian Air.

  14. @10:
    Observing and understanding atmospheric effects on other planets helps us better understand important aspects of atmospheric behaviour better.
    Since extrapolation is often frowned upon in science, it is useful to study atmospheres which are *different* from Earth’s, because this allows us to evaluate our models of reality under circumstances outside the “Earth norm”, which in turn could allow us to verify if our models can be used under many different circumstances.
    If we can build models which can accurately describe the atmospheric behaviour of Venus, Mars, Jupiter *and* Saturn well, we can have more confidence in the ability of such models to also describe Earth’s atmosphere.
    So yes, studying atmospheres on other planets can be very useful in aiding us to understand the behaviour of Earth’s atmosphere. And having a lot more data would be a lot more useful, so lets not wait too long before we send more probes :)

    And yes, the heat trapping abilities of Carbon Dioxide were well known long before we knew of Venus’ Greenhouse effect, but the existence of that effect raises our confidence in our understanding of the behaviour of CO2 in planetary atmospheres, because it creates an indepenent line of evidence confirming our idea. It’s even a good counterpoint to one “pseudo-sceptic AGW-nonbeliever” argument, namely the claim that the CO2 currently in the Earth’s atmosphere already blocks as much radiation as it can block, and raising the levels does not increase the greenhouse effect. Venus clearly proves this claim to be incorrect.

  15. Damon

    I wonder what it would be like to float in the middle of that thing.


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!


See More

Collapse bottom bar