Comments on: Impact-induced rain on Mars?

By: Scott H Florance

Scott H Florance — Tue, 15 Apr 2008 14:14:06 +0000

All stars in space have 21 crystals in their center.

By: Barton Paul Levenson

Barton Paul Levenson — Fri, 11 Apr 2008 16:52:46 +0000

Michael writes:

Considering that the air pressure on Mars is a fraction of what it is on Earth, how can it be sufficient to cause winds and subsequent erosion?

Steven Charles Raine is right. The surface dust is fine and the thinness of the air means less air resistance, so dust storms can hit surface features at hundreds of kph. And with little water erosion, and next to zero oxidation, there’s plenty of time for wind erosion to work.

By: Steven Charles Raine

Steven Charles Raine — Fri, 11 Apr 2008 06:21:40 +0000

The location incidentally is near Mojave crater.

By: Steven Charles Raine

Steven Charles Raine — Fri, 11 Apr 2008 04:36:24 +0000

Asked Michael on 10 Apr 2008 at 11:12 am :

“Since the responders seem to be in the mood to answer questions, I have a quick one. Considering that the air pressure on Mars is a fraction of what it is on Earth, how can it be sufficient to cause winds and subsequent erosion?”

Well I’m not 100 % sure but my underastanding isthat it has something to do with the wind speed and possibly also the sheer fineness of the Martian dust. I think the velocity of the Martian winds make it easier to pick up the dust which is exceedingly fine grained too and this combined with the sheer length of time and absence of other erosive factors makes aeolian (wind-generated erosion) the dominant form of erosian on Mars.

By: Steven Charles Raine

Steven Charles Raine — Fri, 11 Apr 2008 04:32:14 +0000

Wrote The BA :
“Tip o’ the Martian umbrella to Steven Charles Raine for sending me this.”

No worries! My pleasure.

It gives me a real a real buzz to be able to contribute to such a great blog – superluminous (ie,. beyond merely brilliant) write up too!

By: David

David — Thu, 10 Apr 2008 20:33:07 +0000

I thought the impact-induced precipitation theory was a strike against liquid water on Mars (as usually understood), because it raises the possibility that all evidence of liquid water relates to impact events. The idea being that the water would last for a while (many years) because it would create a temporary greenhouse effect.

By: Torbjörn Larsson, OM

Torbjörn Larsson, OM — Thu, 10 Apr 2008 20:13:14 +0000

In essence, each pixel is a light-activated transisitor (if my understanding of CCD technology is correct).

Actually it can be most anything that induces a charge, since CCD really describes the signal transfer (readout) technology – Charge Coupled Device. Essentially a CCD is an array of capacitors.

In practice you use devices that looks like MOS transistors to create the MIS capacitors (by channel capacitance), but AFAIK they don’t have source and drain areas as they don’t really need them. Charge shifting read out instead of transistor read out makes for less noise susceptibility. (Granted, you use transistors further along the signal chain. But with CCD’s you can integrate the signal first.)

And speaking of practice, it is the ubiquitous use of silicon which makes IR a natural part of a CCD photo device spectra due to its convenient bandgap.