Pasadena, Calif. - (AP) - A robotic spacecraft circling Mars has snapped the first image of a series of active avalanches near the planet's north pole.

The image, taken last month, reveals at least four avalanches of fine ice and dust breaking off from a steep cliff and settling on the slope below. The cascade kicked up massive debris clouds, with some measuring more than 590 feet across.

The landslides were spied by the Mars Reconnaissance Orbiter during a routine tracking of seasonal changes. The probe arrived at the planet in 2006.

It is rare for scientists to catch a natural event in action on the surface of Mars. Most of the landscape that has been recorded so far has not changed much in millions of years.

The avalanches occurred near the north pole and broke part of a 2,300-foot cliff.
go

Madness. Here's a piccy.

Sorry am I missing something here? what kind of ice is this?

Mostly "dry ice" (carbon dioxide), although there is a percentage of water ice in the Martian North Polar cap as well...

Does anyone know what the pressures is or temperature is on the Martian surface? As I'm curious as to how dry ice forms naturally. Don't worry this is not a conspiracy theory starting, I am genuinely interested.

No problem...


As in any dynamic system, the pressures and temperatures on Mars vary depending on a variety of factors.

Temperature-wise, Mars gets as warm as about 15 degrees F or so, and as cold as -170 degrees F.
Pressure wise, Mars averages about 0.15 pounds per square inch, or a mere 1% of Earth's normal sea level strandard temperature pressure. That pressure may vary by as much as +/- 15%, again depending on seasonal changes.

One way or another, Mars, despite its appearance in surface photos, is actually a cold, unsurvivable place for human beings....


CO2 freezes at around -79 degrees C, or -110 degrees F, so Mars is, at its poles, plenty cold enough to freeze carbon dioxide, and since probably 95% of the tenuous Martian atmosphere is composed of CO2...that explains the dry ice caps.

Cheers MID,
So is the gas molecules freezing and then combining together to create the ice? it's just there is obviously not enough pressure to turn the co2 into a liquid. (I should stop thinking of water and earthly properties).

Cheers Die...
Yep...C02 at pressures under about 5 ATM, sublimates into gas directly from solid...it can't exist as a liquid, on Mars or on the Earth (save in controlled circumstances here...we can make it happen, but certainly not naturally). At a little more than -78 degrees C, it goes whoosh into gas, and below -78, it freezes solid.

Cheers MID

Hey Mid would this mean when we have totally messed our atmosphere up to the point of no return we will freeze? our thin little warming blanket we call sky when its gone we die!

D:

If humans were capable of actually reducing our atmosphere, and did so to levels approaching a fraction of that present on Mars...I think we'd all be dead long before we froze!

But yea, sure, if we got our atmosphere to up and leave...this place would be a frozen wasteland...

However, I wouldn't lose any sleep worrying about that possibility.

K just wanted to know if the o2 goes away we do too DONTEATUS

Yep...if the O2 goes away, we sure enough do too!

Mid you must know this? what is the highest resolution from a earth based telescope could you get for a close up of the moon ,could you get photo quality pics of the lunar moduals that we parked up there? Im thinking of getting a semi-pro telescope for my son and I hes 11 and ask a lot more questions now days. DONTEATUS You can reply on the profile if you want. Thanks

D:

Unfortunately, no Earth based telescope can resolve objects that small on the lunar surface.
No telescope you could buy, for several thousand dollars or more will help you with that.

A LM descent stage, for instance, is an octagonal structure spanning about 4.5 meters. In order to see that as the smallest object in your image field, you'd need 4.5 meter resolution. I don't know of any telescope, on Earth or on orbit with that capability.

I don't actually know the best Earth-based resolving capability today. I know back in the 60s we had Earth-based images as high as 400 meters, or about 1300 feet, and orbiting satellites far and away exceeded that. Lunar Orbiters got 3 foot resolution in places and Ranger attained terminal resolution of about 5 feet during it's closest photos pre-impact...but that's up there, not down here. I know there's much improved capabilities, but nothing which would come close to imaging clear pictures of a LM descent stage oin the lunar surface.


To get what you call "photo quality pics", which I shall take to mean something crisp and clear and completely identifiable, you really need resolution measured in inches...and that's not possible...unless,


You happen to be there and snap a picture like this:



AS12-46-6749...resolution maybe 1 inch.

If you could find Earth based images of even 10m meter resolution, you wouldn't see what you were looking for. The LM descent stage wouldn't appear. Even at the 3 foot, say 1 meter resolution of the Lunar Orbiters, a LM would be an obscure dark spot on the frame...possibly presenting an identifiable octagonal shape...but certainly nothing clear.


But a fine amateur telescope is a great investment...a great deal can be learned through one of them. Imaging Apollo lanbding sites is frankly, impossible from Earth, exceedingly difficult from lunar orbit, and isn't a consideration for serious astronomers.

This is what you might expect out of a relative large aperture scope (in this case a Celestron C11 (11 inch diameter Schmidt-Cassegrain telescope)).




The larger crater is Copernicus, about 58 miles across. This is a great and detailed view, which spans about 245 miles across, a little more than 1/10 of the lunar diameter viewed at very good detail. But the smallest feature you can actually see here is about 2 miles across....and that's with a telescope that you'll spend close to $2,500.00 on.

Find the very smallest crater you can hope to visualize on this shot and the largest Apollo landing site would fit inside that spec...including the trails of almost all the LRV traverses. It's actually a big place, and the LMs are very, very tiny...

well that put a real answer to my question.and the LM pic was great. May just have to wait till we return to the moon and buy some pics.I wonder if you can download pics like you did direct from a nasa file? My kid & myself could use some of those around the shop here in dallas Thanks DONTEATUS

I'm glad to be of help, D!

Sure you can get all the pictures at NASA:

The best on-line source for Apollo information...in fact the best all-around source for it anywhere.

APOLLO LUNAR SURFACE JOURNAL

When you get over there, click on the "Journal" section for any particular mission. You'll find about everything you ever wanted to know about each of the lunar landing missions including an Image Library for each. The pictures are all there, most of them having special high resolution scans with incredible detail available.


You could spend a year just looking at that...let alone looking into all the other amazing information they've compiled there.

M~

I know a few old nasa guys from texas in my car bussiness here in dallas you might of heard of them? PeterArmitage,and Dick Bowman good texans DONTEATUS ?