Glenn asks:

> >A reason for that lessened coverage may be the natural tension that exists
>  >within NASA between manned and unmanned space flight operations. At the
>  >time as the briefing, the Endeavour crew will be doing some truly major
>  >construction operations on the International Space Station, which is
always
>  >a little dangerous.
>
>  That makes some sense, though I still wouldn't expect a week's delay
>  for a truly major discovery.

I suspect that the NASA announcment was released early simply because the
news leaked out before it should. When you submit a paper to a journal, they
(irritatingly) assume all copyrights to article, not the original author.
Although these rights are extremely rarely contested, and the authors
(generally a bunch of university professors who have no profit motive) pretty
much do anything they want anyway, the rights do become important in some
high-profile work. Secondly, for the premiere-tier journals (Science and
Nature, especially), you have to sign an agreement that you will not make the
work public until the day of publication of the paper.

Because this work was submitted to Science, and because so much money rides
on these sorts of results (they determine the course of the next decade's
research dollars), everyone (authors, reviewers, editors) play everything
very close to the vest and very carefully observe the rules. However, in this
case, the information apparently leaked out early.

As "youthrights" quite likely rightly wrote:

=======================================

This MAY be the answer to what NASA will announce courtesy of The Sunday
Times UK December 3, 2000 edition:

"Dried-up sea beds found on Mars

 NASA scientists have discovered ancient sea or lake beds on
 the surface of Mars that could once have harboured life, writes
 Jonathan Leake.

 The discovery is among the most significant concerning Mars
 so far, because such places are the most likely locations for
 fossils or other signs of past life.

========================================

I heard about this article just minutes after I wrote my earlier reply -- and
at first I dismissed it as possibly a joke, simply because the author was
"Jonathan Leake".

It may be a joke, or it may not. Under any circumstance, the discovery of
dried up seabeds would not be a surprise. Virtually everyone has been
expecting that. Episodically free-flowing water on the surface of Mars is now
essentially universally accepted. Evidence of ancient water (three to four
billion years ago) would be no surprise. Evidence of recent water, sufficient
to cause contemporary erosional patterns, would be a big deal.



>  >Nonetheless, if I were go guess as to what major discovery was to be
>  >announced (given that it was observed from orbit), it would likely be
>  >(i) some tangible evidence of vulcanism on or near the surface of Mars (so
>  >far, nothing reliable has yet been observed), or (ii) even more
importantly,
>
>  >evidence of the effects recent liquid water, even if underground, as
occurs
>  >in karst-like geomorphologies.
>
>  I'll ask a naive question.  At
>
>     http://aics-research.com/sojour21.html
>
>  :) is the "Presidential Panorama" of Mars.  Included in the text is:
>
>    "This red silt is composed in large part of iron oxide.
>     The surface of Mars is literally rusting."
>
>  Can rust occur without the presence of water?

"Rust" doesn't require water, only free oxygen (and a bit of energy). Rust is
merely iron oxide in several various forms. That oxidation can occur in an
instant, as when steel wool is ignited in a pure oxygen environment, or it
can take millennia.

However, Mars isn't without water. It exists in sufficient quantities in the
atmosphere right now to seasonally form frost pretty much everywhere on the
planet, but especially in the polar regions. Indeed, much of the water on the
planet may be "permanently" cold-trapped in a rock-ice matrix called
permafrost. The detection of this permafrost is a good portion of what we're
going to be looking for over the next 10 to 20 years. See:

     http://www.science.nasa.gov/newhome/headlines/ast27jul99_1.htm

When I was younger, I lived, worked, ate and slept on permafrost at the
northern extreme of Greenland for six months, and it was an interesting
experience. It's unlike any other rock on which you've ever stood: hard as
steel, but also elastic as steel. You could lay in bed and feel a truck shift
gears anywhere on the base at Thule, Greenland.

Telephone poles were put in place by drilling down a few feet -- and then
using explosives to blow the rest of the four to six foot hole. The telephone
pole was put into the hole, dirt was tamped back in, and then warm water was
poured around the pole. The pole was held up by a truck until the water froze
solid, which was about 5 to 15 minutes. After that, you would never be able
to get that pole out of the ground again.

However, if the permafrost ever does melt, enormous amounts of water are
squeegeed out of the ground by the collasping rock. You can see direct
evidence of this subsidence and subsequent flow in the Martian topography in:

     http://zebu.uoregon.edu/ph121/jsimages/slump.gif

This is isn't the best image that we have of this process. It's merely the
first one I could find. Nonetheless, you can clearly see the liquification of
the resulting mud flow and the liquid water outflow streaming off to the
lower right. Further, it's also easy to see that this slump is much younger
than the slumps to its left in the image.

Wirt Atmar