UV Light Colors Great Red Spot




This is Scientific American's 60-Second Space. I'm Lee Billings.Got a minute?
When I say "Jupiter," what comes to mind?
Chances are, you pictured a banded orb of gas marked by a big red oval, the giant planet's Great Red Spot.
Scientists have long known that the Great Red Spot is a huge whirling storm rising high above the surrounding cloudtops.
But the reason for its reddish hue has been a mystery.
One leading theory has been that red-colored compounds are swirling up from deeper down to tint the Spot, a bit like the blush from blood rushing to your cheeks.
Now, new results presented at recent meeting of the American Astronomical Society are suggesting something different.
Working at the NASA-Caltech Jet Propulsion Lab in Pasadena, California, researchers exposed two chemicals abound on Jupiter, ammonia and acetylene to levels of ultraviolet light like those found near the top of the planet's atmosphere.
The ammonia and acetylene turned a shade of red very similar to the Great Red Spot's, as seen up-close by passing spacecraft.
But the lab compounds only matched the Spot's color if on Jupiter they were confined to its highest cloud tops.
If they were whirling up from beneath and distributed through all of the Spot's layers, the Spot would be a much more brilliant crimson hue than its present pale red color.
So it looks like UV light's effect makes Jupiter's Great Red Spot , less of a blush and more of a sunburn.
Thanks for the minute, for Scientific American's 60-Second Space. I'm Lee Billings.