Y’know, I’m not all that big on “Mystery Baffles Scientists!” kinda headlines, but I have to admit, this scientific mystery is rather baffling.
What’s causing hundreds-of-kilometer-high plumes on Mars?
This is pretty weird. Amateur astronomers taking images of the Red Planet spotted cloudlike features well above the surface. And I do mean well; some are 250 kilometers in altitude. That’s way above where you normally find clouds.
They’ve been seen on multiple occasions, and by Hubble as well. They’re not image artifacts or some processing mistake in the pictures. They rotate with the planet, and are certainly real.
[A Mars plume was spotted on Mar. 20, 2012. Photo by W. Jaeschke. Click to embiggen.]
Mars has an atmosphere, though it’s thin, less than 1 percent of Earth’s pressure at sea level. It’s enough to stir up dust storms and other weather on Mars. It even can make clouds: As winds blow up the slopes of the planet’s huge volcanoes, for example, carbon dioxide can condense and form what are called orographic clouds (this happens on Earth too; I see it all the time since I live near the Rocky Mountains, with water instead of carbon dioxide of course).
Still, it’s hard to see how the Martian air could blow something like dust or CO2 as high as these plumes. It’s possible, though unlikely, that it could be some gas in the atmosphere that’s getting up that high, condensing, and forming reflective clouds.
But it’s just so far above what’s normally seen that this doesn’t hold water with me.
Another idea is that it’s auroral activity. Mars doesn’t have much of a magnetic field, but there are areas on the planet that do have stronger magnetic fields. The solar wind coming in from the Sun could be funneled into the atmosphere there, causing the glow. Although the press release doesn’t mention it, I suspect observing Mars in the ultraviolet might help; aurorae glow at those wavelengths.
You’d think that we have plenty of space probes orbiting the planet and that one of them would’ve seen something by now. The problem there is, in a way, being too close. The best way to see these things is on the edge of Mars, against the darkness of space. Most of the orbiting missions at Mars look straight down, and can’t see these plumes.
Not that observing them from Earth is all that easy. The problem is that these aren’t persistent features. They come and go, making observing them difficult. In cases like that, the best bet is brute force: Observe Mars a lot. Get as many telescopes observing it as often as possible and in as many ways as possible (imaging, video, different wavelengths, and so on). Small probability events become certainties given enough time.
I’d love to know what these things are. Giant plumes of gas erupting from Mars sound a little ominous to me. If there’s an observatory in Grover’s Mill, I hope it’s paying close attention.