Monday, November 15, 2010

Jupiter's face changes

The face of Jupiter has had some dramatic changes this year and no cosmic plastic surgeon is to blame.

Being in astronomy, many people have expressed how amazing they find the sky, but sometimes they express some incredulity, too. "Really, what's so amazing about it? It's the sky! It doesn't change."

But nothing could be further from the truth! Planets can change features all the time and Jupiter can be the most mercurial of the lot. A planet made of up mostly gas, over 1,000 times more mass than our planet made up almost entirely from hydrogen and helium, heated from within and rotating once every nine hours - it tends to have a lot of weather.

Most prominent of its features are its cloud bands. Alternating light and dark, they represent massive areas of high and low pressure. Ammonia and other chemicals contributes a lot to the colours of the planet that we see.

Girdling Jupiter's equator are two darker "belts," a northern belt and a southern one. And earlier this year, Jupiter appeared in the night sky with it's south equatorial belt faded out of view.

This isn't the first time it's happened. Indeed, I recall at least one incidence in the early '90s when Jupiter's south equatorial belt disappeared.

Most recently, amateur astronomers have noted that the SEB is experiencing a resurgence. What started as a fairly bright spot has been showing signs of bringing back the SEB, much as it has done several times over the last few decades. Astronomers, both professional and amateur alike, have been watching Jupiter in hopes of seeing the re-emergence of the SEB.

Of course, the downside of this is that the famous Great Red Spot is more difficult to spot. Oh well, win some, lose some!

Unfortunately, as is typical for this time of year in Southern Ontario, the weather has been anything but clear! No doubt, the next time I have a chance to view it, the view will be a lot different than this past summer. And who says the skies never change!

Clear skies!

Jupiter before...

And Jupiter after, without it's southern equatorial belt but with a prominent Great Red Spot. But things are changing. Here comes the SEB!

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