From: LARRY KLAES (ljk4_at_msn.com)
Date: Fri Oct 03 2003 - 18:56:39 PDT
----- Original Message -----
From: daviddarling123
Sent: Friday, October 03, 2003 9:49 PM
To: DarlingsSpace_at_yahoogroups.com
Subject: [DarlingsSpace] David Darling's Newsletter #15
DAVID DARLING'S NEWSLETTER
--------------------------------------------------
Issue #15
October 3, 2003
e-mail: darling_at_uslink.net
website: http://www.daviddarling.info
--------------------------------------------------
Contents
1. Meanderings
2. Life on Mars
3. Bookends
--------------------------------------------------
1. Meanderings
A belated greetings, everyone. The Yahoo Groups site has been down
for a bit, so, for the benefit of those who receive it that way, I
was holding off with the newsletter until the glitch was resolved.
This last week has seen the first blast of wintery air arrive in
Minnesota, with temperatures dipping well below freezing at night
and the leaves rapidly changing to a delightful mixture of reds,
oranges, golds, and browns. It would be perfect except for the
thought that we'll soon be running our annual five-month-long Pluto
simulation!
With a great deal of help from my son-in-law, Murray Etherington,
I've now set up a new version of my website hosted by Globat which
will allow for a lot more expansion, traffic, and nifty facilities.
As I write, the domain name www.daviddarling.info is in the process
of being transferred to this new location. This means that if you've
been accessing my site via www.daviddarling.info, instead of the
more cumbersome www.angelfire.com/on2/daviddarling, you'll
automatically go to the new version when the switchover takes
effect. I'll still be maintaining the old angelfire-based site for a
couple of months to allow for a smooth transfer of traffic, but if
you have a bookmark that points to the old URL or to any of the
pages within the angelfire site, I suggest you update this to point
to the new address. Let me know if you run into any problems or if
seems like I'm talking Greek.
At first glance, when you go to the new site, you'll notice nothing
different. But if you look more closely in the menu items at the top
of the front page (and on every other page of the site), you'll see
that a new item has appeared: "bulletin board". This is something
that people have been asking that I set up for quite a while. It's a
multithread forum hosted by PHP and is a great way to get involved
in a discussion or argument on any topic related to the site --
astronomy, life in the universe, spaceflight, faster-than-light
travel, time machines, cosmology, teleportation, the nature of
consciousness, my books, you name it. In fact, you can literally
name it by setting up your own thread and starting a new dialog.
These things tend to be organic by nature, so I've no idea how it
will develop. I'm putting up a few topics to get started, but you
can take it anywhere you like. It'll make the site a lot more
interactive and fun. Don't be shy -- please plunge in and have your
say. I'm hoping especially that newsletter subscibers will get
involved so that I can learn more about you and your interests.
Incidentally, if you've something you want to say right away,
without waiting for the www.daviddarling.info name to hop over, you
can access the new site by going to
stcroix.globat.com/~daviddarling.info. Please drop me a line if you
run into any broken links or other anomalies -- there are bound to
be a few. You can also check out a couple of pictures I took on our
summer trip to England by going to the "me" page on the new site and
following the link from there. (Apologies to Mike B. from Australia
who asked that I visit the Green Slate Company in Honister Pass,
just for him. I didn't make it this time -- my wife refuses to
travel by road on Honister or Hardnott and Wrynose Pass after an
unfortunate encounter with a sheep some years ago. But I'll get
there next time!)
In the last issue of the newsletter I rambled on about time travel
(past newsletters are also available on the new site, by the way),
and asked if anyone could remember who wrote the old classic science
fiction tale in which a time traveler goes back to the age of the
dinosaurs, inadvertently steps on a bug, and because of that, alters
the future course of the world. Thanks to Larry Klaes and Daniel
Handlin for supplying the missing data: the bug was a butterfly, the
story was "A Sound of Thunder," it was first published in 1952 in R
is for Rocket, and the author was none other than Ray Bradbury. In
fact, you can read the story here:
http://www.sba.muohio.edu/snavely/415/thunder.htm
And so to this issue's topic. Even as we speak, four spacecraft are
converging on the planet Mars to try to pry away some more of its
intriguing secrets. They're the European Mars Express
(http://www.angelfire.com/on2/daviddarling/MarsExpress.htm),
carrying the Beagle 2 lander
(http://www.angelfire.com/on2/daviddarling/Beagle2.htm), the twin
NASA Mars Exploration Rovers
(http://www.angelfire.com/on2/daviddarling/MarsExplorationRovers.htm)
, and Japan's Nozomi orbiter
(http://www.angelfire.com/on2/daviddarling/Nozomi.htm). What will
they find when they arrive? Most importantly, will they uncover
evidence of life?
-------------------------------------------------
2. Life on Mars
The question of Martian biology goes back centuries, but first
became a hot topic in the last quarter of the nineteenth century,
when Schiaparelli
(http://www.angelfire.com/on2/daviddarling/Schiaparelli.htm) and
others, most notably, Percival Lowell
(http://www.angelfire.com/on2/daviddarling/LowellP.htm), thought
they'd seen water channels or even canals on the surface of the
fourth planet. Lowell's obsession with advanced Martian intelligence
and a civilization that had built a complex irrigation system to
carry meltwater from the polar caps to the arid regions of the
planet fired the popular imagination. And I don't think that
fascination with a dying extraterrestrial civilization on our cosmic
doorstep has ever really gone away. Here's my illustrated
encyclopedia page on the canals saga:
http://www.angelfire.com/on2/daviddarling/Marscanals.htm. It's a
story that, while, unfortunately, long discredited by observational
evidence, is too compelling and exciting to relinquish its place in
the romance of the Solar System. We badly want it to be true that
there was a companion technological race on the Red Planet, and so
we still seek signs for it in space probe imagery at the edge of
resolution just as Lowell strained to see what he wanted to see in
the faint, small disk of Mars imaged by the 24-inch Clark refractor
at his purpose-built observatory at Flagstaff.
Now, don't get me wrong. I'm not averse to people poring over photos
of Mars sent back by Mars Global Surveyor and, more recently, by
Mars Odyssey, in the hope of seeing ruined monuments, cities, and
even extant life. I regularly receive requests to look at shots,
processed or otherwise, that purport to show Martian
pyramids, "glass tubes," colossal sand worms (a la Dune), and so
forth. I never pour scorn on these pictures or their senders. (In
fact, any "anomalists" are cordially invited to present and defend
their case on the new bulletin board!) As soon as a scientist
refuses to look at any data with a fresh eye and mind, he may as
well pack up his bags and leave town. But I'll always, without fail,
apply Occam's Razor. That is, faced with an unknown or indeterminate
phenomenon, I'll always go for the most mundane explanation -- the
one that calls for the least spectacular and number of explanations.
Lowell thought he saw hundreds of networked straight lines and took
them to be canals. He was wrong: they were an optical illusion.
Armchair theorists today argue that they can see geometric shapes,
alignments, forests of banyan-like trees, megalithic humanoid faces,
etc -- evidence of advanced life. I hope they're right. I strongly
suspect they're wrong. I know that Mars has a long history of
kidding people into thinking that it harbors visible traces of life,
animal and vegetable. That isn't Mars' fault. It's ours, because we
(me included) so desperately want to find those traces. It's a very
human failing that when we want to believe in something badly
enough, our minds work hard to invent or suitably interpret the data
needed to shore up that belief.
Well, our outward-bound probes aren't going on a hunt for lost
Martian cities or technological remains. But one of them at least,
Beagle 2, is going to be sniffing the air and sampling the soil of
the Red Planet to see if there are any signatures of microbial life.
If it finds a minute dash of methane in the atmosphere, for example,
that would be very suggestive (though not proof) of methanogenic
bacterial action. If Beagle detects traces of organic material in
the soil, collected by a miniature "mole," that too will point the
finger in the direction of life. Remember, there are still many
unanswered questions about the results sent back by the twin Viking
probes (http://www.angelfire.com/on2/daviddarling/Viking.htm).
So what are the chances for Martian biology? The good news is that,
in its early stages, Mars was a lot more like the Earth than it is
now. It was certainly warmer and had liquid water on its surface in
the form of run-off channels, lakes, and possibly extensive seas. It
would have been much more geologically and tectonically active, and
possibly had hydrothermal vents of the type that, on Earth, are on
the list of "genesis sites" -- locations where life may first have
emerged and developed. In fact, as I argue in my book Life
Everywhere, it might be more puzzling if we find no evidence of any
Martian biology at all, past or present. If Mars never acquired
life, what was it about Earth that was so special? What did we have,
four billion years ago or thereabouts, that Mars didn't. I'd
personally put the odds of past Mars life at better than 75% because
of the similar conditions.
What about life on Mars today? That's a lot more problematic. Mars
today isn't too friendly, at least on or just below the surface, to
the kind of life we know. It's bone dry, very cold for the most
part, and, worst of all, is strafed continually by high-energy solar
radiation. Harsh solar UV, cosmic rays, and the like, have surely
sterilized the soil at ground level and down to at an indeterminate
depth. There's a very good chance that the surface regolith is rich
in highly oxidizing compounds, such as superoxides, that would be
devastating to terrestrial biology. These powerful oxidants may very
well (but not conclusively) explain the anomalous Viking lander
results. They may also frustrate Beagle 2's attempts to find
biological matter. But set against these negatives is the possibly
that if life had emerged on Mars in the remote past it might have
gradually adapted to the current harsh regime (we have some bacteria
on Earth, such as Deinococcus radiodurans, that are incredibly
resistant to high doses of radiation) and/or retreated to a more
clement environment deeper underground. Getting at deep subterranean
(or "subareolian") life, tens of millions of miles from Earth, might
be a bit tricky, calling for advanced penetrator probes or even a
human-crewed drilling rig. But I suspect that several hundred
meters, or even a kilometer or more, down is where we have our best
chance of encountering living Martians.
Our search for life, at least within the Solar System, is first and
foremost a search for liquid water. Good old H-Two-O is a sine qua
non of life as we know it. We can speculate about life based on a
different solvent, such as ammonia or hydrochloric acid. But we
really haven't a clue how it would work biochemically and we
certainly wouldn't know what biomarkers to look for. (We have a hard
enough time searching for small traces of Earth-like life!) The fact
is that we know of at least one form of life that depends critically
on the availability of water in its liquid form and we know that
water has some extraordinary properties that make it hard to replace
in a biological context. So, it makes sense to look for water first
and then ask if there might be life nearby. That's why
astrobiologists are so excited about Jupiter's moon Europa, because
there are strong signs that it has a sub-ice watery ocean. Mars is
harder to read on this point. Its atmospheric pressure is extremely
low -- around 7 milllibars, on average, which is less than one-
thousandth the surface pressure on Earth. Water just vaporizes --
essentially boils -- away very quickly under these conditions. So
you really can't hope to find watery pools lying around Mars today.
On top of this, of course, it's pretty cold in most places on Mars,
most of the time. Pick a time and location on Mars at random and the
chances are it would make Antarctica seem balmy. And yet we know
Mars has lots of water ice. Most of its poles and much of its rocks
seem to be rich in the stuff. So, if there are mechanisms to
temporarily melt this ice, you could have liquid water on or just
beneath the surface for brief periods. If you go to the front page
of my website you can find an image that seems to show dark stains
that have appeared on extensive regions of the Martian surface quite
suddenly, over a period of a year or so. We don't know what these
stains are or what has caused them. One theory is that they
represent water melted by tectonic activity. Another theory, put
forward by NASA's Chris McKay, is that they may be due to the spread
of bacterial colonies during a short spell when moisture becomes
available. McKay, incidentally, has also suggested that plenty of
free oxygen may have been available on Mars in its early stages,
opening up the possibility that not only life, but possibly advanced
life could have evolved there between 3.5 and 4 billion years ago.
So, the door is slightly ajar to you anomalists!
And then there are those Martian meteorites. Do they really contain
evidence of life as some researchers claim? It gets down to the
origin of certain magnetite crystals in meteorites such as ALH84001
(http://www.angelfire.com/on2/daviddarling/ALH84001.htm). The pro-
life claim is that exactly the same kind of crystals are produced
biologically -- and only biologically -- on Earth; so, given that
they almost certainly came from Mars, they were probably laid down
by magnetotactic bacteria on the fourth planet. Well, maybe. But
it's pretty thin evidence when stacked up against such a momentous
issue: the question of the existence of life beyond Earth. Maybe
there are ways to produce these crystal chains by purely chemical
means that we don't know about. Maybe they're contaminants (though
this seems unlikely). We're not going to settle the problem of
Martian life, once and for all, to everyone's satisfaction, through
rocks that have been blasted our way, have spent millions of years
floating around in space, and have lain around on Earth for
thousands more years. We need pristine material from the Red Planet
itself: we need to find life, or its remains, in situ. Perhaps
that's what Beagle and the other space hounds currently bound for
Mars will do.
----------------------------------------------
3. Bookends
Where can you find the latest, greatest guide to the astronomical
world, complete with more than 3,000 cross-referenced entries and
230 illustrations (including 8 pages of color photos)? What is the
most complete and up-to-date encyclopedia of this astonishing cosmos
in which we live? Why, The Universal Book of Astronomy, of course!
More on this newest book of mine, about to be published by Wiley and
a companion to last year's Complete Book of Spaceflight, on my
website, at Amazon.com, and Barnes&Noble.com. Buy your copy now,
while stocks last!
Until next time,
Best wishes,
David Darling
This archive was generated by hypermail 2.1.6 : Fri Oct 03 2003 - 19:08:55 PDT