+ . * . . . + . . +
. . . db . . . . . + + . .
+ . . .d88b . . + . ,d . . . . . . .
. . . d8'`8b + . . . 88 . + . . . + .
. + d8' `8b . ,adPPYba, MM88MMM 8b,dPPYba, ,adPPYba, . .
. . . d8YaaaaY8b . I8[ ."" . 88 . 88P' . "Y8 a8" . "8a * .
+ . . d8""""""""8b `"Y8ba, .88. 88 + . 8b . d8 . +
. .d8' + . `8b aa . ]8I 88, .88 * "8a, . ,a8" + .
. . d8' . + `8b `"YbbdP"' + "Y888 88 . . `"YbbdP"' . . .
. d8' + . . * .. . .. . + . . . . .
* .d8' . T H E A R M C H A I R A S T R O N O M E R . + .
. + . + .. . . . + * . . +
///////////////////////////////////////////////////////////////////////////
/// VOLUME I, NUMBER 3 MARCH 1995 ///
///////////////////////////////////////////////////////////////////////////
I N T H I S I S S U E
The parenthetical reference numbers at the beginning of each line in the
table of contents can be used to search ahead for any particular article of
interest. Note that the subject lines will vary from those shown in the
table of contents, so just use the numbers for your searches.
(-01-) From the Editor
(-02-) COLUMN This Month in Astronomy
(-03-) COLUMN The Software Page
(-04-) COLUMN The Net Surfer
(-05-) NASA More News from Hubble
(-06-) NASA Topex Confirms El Nino is Back
(-07-) NASA The Space Shuttle/Space Station Mir Rendezvous
(-08-) NASA X-ray Telescope Mirrors Complete
(-09-) SKYWATCH Occultating Venus
(-10-) ASTRONET Moon Months
(-11-) ASTRONET Carl Sagan vs. Immanuel Velikovsky
(-12-) COLUMN Planetarium News ()
(-13-) ASTRONET Superluminal Jets Illuminate Black Hole Research
(-14-) ASTRONET Light Pollution Victory!
(-15-) ASTRONET The Galaxy on its Side
(-16-) Why Explore Mars?
(-17-) Welcome to Mars!
(-18-) NASA Radar Studies Agkor, Cambodia Archeological Sites
(-19-) Subscription and Other Pertinent Information
///////////////////////////////////////////////////////////////////////////
(-01-) F R O M T H E E D I T O R
Welcome to the third issue of _The Armchair Astronomer_, a monthly e-zine
devoted to the study and application of astronomy and its impact on the
average layperson.
I apologize for the lateness of this issue. It's thesis time in the
lifecycle of this grad student, and deadlines are looming and priorities
are shifting. Fear not, neither rain nor shine nor assistantship nor
thesis will keep this electronic deliveryman from making his rounds. He
_may_ be a little late with it, though... ;)
TURN OFF YOUR LIGHTS -- TURN ON TO ASTRONOMY
- Todd
18 March 1995
///////////////////////////////////////////////////////////////////////////
(-02-) T H I S M O N T H I N A S T R O N O M Y - M A R C H
Every month this column will try to prepare readers for upcoming
astronomical events both up in the sky and down on the ground.
If you know of an event that should be posted here, please send
mail to vanhoose@lalaland.cl.msu.edu.
9 FEB marks the 5th anniversary of the 1990 VENUS FLYBY by the GALILEO
SPACECRAFT. MARS is in OPPOSITION on 11 FEB. 17 FEB marks the 65th
anniversary of the DISCOVERY OF PLUTO by CLYDE TOMBAUGH.
///////////////////////////////////////////////////////////////////////////
(-03-) T H E S O F T W A R E P A G E
The Software Page is a place for announcements and reviews of
new astronomy-related software (both commercial and shareware).
If you have a product that would like to be reviewed or promoted
in this column or if you have a review of a package that you would
like to share, please send e-mail to vanhoose@lalaland.cl.msu.edu.
FROM THE UNIVERSITY OF MICHIGAN MACINTOSH ARCHIVES (mac.archive.umich.edu)
FROM ELWOOD C. DOWNEY (iraf.noao.edu)
contrib/xephem/xephem_2.6 Xephem 2.6 Interactive Astronomical
Ephemeris Program for X-Windows & Motif
Xephem is an interactive astronomical ephemeris program for X Windows
systems. It computes heliocentric, geocentric and topocentric
information for celestial objects. Xephem has built-in support for
all planets; the moons of Jupiter, Saturn and Earth and Mars' central
meridian longitude. Xephem supports objects in heliocentric or Earth
orbit given the appropriate elements. Sample databases of over 16000
objects are included in the release kit. Xephem generates data in
configurable tabular forms and in several detailed graphical formats.
Xephem can plot and list all data fields and can be programmed to
search for arbitrary circumstances. Xephem can serve as the control
point for automated telescopes and can connect to auxiliary database
servers in real-time via named streams pipes (UNIX fifos).
///////////////////////////////////////////////////////////////////////////
(-04-) T H E N E T - S U R F E R
This column explores the frequently uncharted waters of the Internet
in search of sites, files, web pages and anything else that is
related to the study and application of astronomy.
Jenny Pon from MSU's Abrams Planetarium has identified a few more points
of interest out there in the Web for us:
Space Telescope Science Institute
http://marvel.stsci.edu/top.html
Page from MSU Physics-Astronomy Dept.
http://pads1.pa.msu.edu/pages/physics-interest.html
///////////////////////////////////////////////////////////////////////////
(-05-) Date: 13 January 1995
Subject: Hubble's '94 comeback due in large part to WFPC-2
From: The JPL Universe
RECOVERING HUBBLE
NASA's Hubble Space Telescope made a spectacular comeback in
1994 after its primary camera, the Wide Field and Planetary
Camera, was redesigned and installed to compensate for flaws
caused by the telescope's primary mirror.
The second-generation camera, built by JPL, carried corrective
optics that fully restored the planned imaging capability of HST,
an achievement that sent ripples through the scientific community
and awed the public when the first pictures using the new camera
were unveiled in January 1994. Dr. John Trauger of JPL spearheaded
the redesign effort.
The first images released on Jan. 13, 1994, revealed crystal-
clear shots of galaxies at the distance of the Virgo cluster some
65 million light-years away. Other images included the first well-
resolved shots of newly forming stars in the nearby Orion nebula
and a previously unseen structure in the exploding star Eta
Carinae, located in one of the Magellanic clouds just outside the
Milky Way galaxy.
As the year progressed, Hubble's WFPC-2 took part in one of the
most fantastic events in the history of planetary science, when
fragments of the comet Shoemaker-Levy 9 began bombarding Jupiter
over a six-day interval in mid-July.
Other significant events for the Wide Field and Planetary
Camera-2 included the first accurate measurements of the distance
to a remote galaxy in the Virgo cluster.
Scientists determined the distance of M100 to be 56 million
light-years away, based on their measurements of newly discovered
Cepheid variable stars too faint to be seen by ground-based
telescopes. The accomplishment represented a major milestone in
one of the Hubble Space Telescope's primary science goals-- to
determine the Hubble constant--the ratio of the velocity of
recession of galaxies to their distances, as proposed by Edwin
Hubble early in the 20th century.
"Hubble is allowing us to make observations in a few short
months that used to take a decade or more to complete," said Dr.
Barry Madore of the NASA Infrared Processing and Analysis Center
and a member of the Hubble Extragalactic Database at Caltech.
"This was an objective that was nothing more than a wish and a
dream to astronomers five years ago."
In later developments, a team of scientists from the Princeton
Institute for Advanced Study and the Hubble Telescope Science
Institute used WFPC-2 to study red dwarf stars, which were thought
to constitute perhaps as much as 90 percent of the invisible, so-
called dark matter in the universe. Their observations, too,
turned the astronomical community upside down.
WFPC-2 closed out the year with another spectacular
observation. In December, the telescope returned images of Saturn,
which revealed a rare storm sweeping across the planet's upper
atmosphere. The photos provided the science community with new
details about the effects of Saturn's winds on storm systems.
As 1995 gets under way, astronomers are scrambling for
observing time to turn Hubble's powerful telescopic eyes on new
science targets within the solar system and far beyond it. In
fact, some astronomers are predicting that the orbiting telescope
will be able to peer back at galaxies as far as 150 million light-
years away and, before long, provide answers to some of the most
fundamental questions in astronomy today.
///////////////////////////////////////////////////////////////////////////
(-06-) Date: 24 Jan 1995
Subject: Topex Confirms El Nino is Back
From: NasaNews
TOPEX/POSEIDON CONFIRMS EL NINO IS BACK AND STRONGER THAN IN 1993
The El Nino phenomenon is back and is getting stronger, according to
scientists studying data from the ocean-observing TOPEX/POSEIDON
satellite.
El Nino is a climatic event that can bring devastating weather to
several parts of the world, including the recent heavy rains and
flooding in California, and the warmer than normal winter in the
eastern United States.
"The satellite has observed high sea-surface elevation, which reflects
an excessive amount of unusually warm water in the upper ocean," said
Dr. Lee-Lveng Fu, JPL TOPEX/POSEIDON project scientist at NASA's Jet
Propulsion Laboratory, Pasadena, CA. "The associated excess of heat
creates high sea-surface temperatures, which affect the weather
worldwide by heating the atmosphere and altering the atmospheric jet
streams."
Jet streams are high-level winds, five to ten miles above the Earth's
surface, created when warm and cold air masses meet. Shifts in the
location of jet streams change temperatures and precipitation zones at
the surface.
El Nino begins when the westward trade winds weaken and a large warm
water mass, called a Kelvin wave, is allowed to move eastward along the
equator in the Pacific Ocean. Data from the radar altimeter onboard
TOPEX/POSEIDON, recorded from October through December 1994, reveal a
new Kelvin wave moving toward the western coast of South America.
"This wave is currently occupying most of the tropical Pacific Ocean.
It will take another month or two before the wave disperses. Compared
to the El Nino condition of the winter of 1992-93, the present one
appears somewhat stronger and might have stronger and longer lasting
effects," Fu said.
TOPEX/POSEIDON, a joint program of NASA and the Centre Nationale
d'Etudes Spatiales, the French space agency, uses a radar altimeter to
precisely measure sea-surface height. Scientists use the
TOPEX/POSEIDON data to produce global maps of ocean circulation.
Launched Aug. 10, 1992, the satellite has completed two and a half
years of its three-year prime mission and has provided oceanographers
with unprecedented global sea level measurements that are accurate to
better than 2 inches (5 centimeters).
"The global sea-surface elevation information provided by
TOPEX/POSEIDON is unique because it is related to the amount of heat
stored in the upper ocean, which is important for long-range weather
forecasting. The speed and direction of ocean currents also can be
determined from the elevation information, providing another piece of
critical information about the ocean, which is the key to climate
change," Fu continued.
TOPEX/POSEIDON is part of NASA's Mission to Planet Earth, a
coordinated, long-term research program to study the Earth's global
environment. TOPEX/POSEIDON's sea-surface height data are essential
to understanding the role oceans play in regulating global climate, one
of the least understood areas of climate research. TOPEX/POSEIDON will
provide the first comprehensive, consistent measurements of the
circulations of the ocean. The Jet Propulsion Laboratory manages the
TOPEX/POSEIDON mission for NASA.
NOTE: the following images are available from ftp.jpl.nasa.gov:
/images/browse/elnino2.gif JPL photoproduct P-45140 (90k)
/images/hi-res/p45140.tif Full-res version (11140k)
/images/hi-res/p45140.txt Caption for P-45140.tif (3k)
///////////////////////////////////////////////////////////////////////////
(-07-) Date: 10 February 1995
Subject: The Space Shuttle/Space Station Mir Rendezvous
From: NASA Press Kit
RENDEZVOUS WITH RUSSIAN SPACE STATION HIGHLIGHTS FIRST
SHUTTLE FLIGHT OF 1995
A significant step in the growing cooperative effort between the United
States and Russia took place during NASA's first Shuttle mission of the
year when Discovery and her crew performed a rendezvous and fly around
of the Russian Space Station Mir in preparation for a Shuttle/Mir docking
mission due to take place later this year.
"As we are bringing our space ships closer together, we are bringing
our nations closer together," said STS-63 Commander Jim Wetherbee after
Discovery reached the point of closest approach. "The next time we
approach, we will shake your hand and together we will lead our world
into the next millennium."
The two spacecraft came within 37 feet of each other. The rendezvous
validated a number of flight techniques that will be employed on
subsequent docking missions. These techniques include the use of
precision flying as the Shuttle closes in on Mir and demonstrating the
joint operations between Mission Control Centers in Houston, and
Kaliningrad, Russia.
///////////////////////////////////////////////////////////////////////////
(-08-) Date: Jan 30 19:45 UTC
Subject: X-ray Telescope Mirrors Complete
From: NasaNews
NASA'S X-RAY TELESCOPE MIRRORS COMPLETED AHEAD OF SCHEDULE
A space-based observatory, under construction for NASA, has met an
important milestone--polishing and measurement of the observatory's
eight mirrors, one of the project's toughest technical challenges, has
been completed four months ahead of schedule at Hughes Danbury Optical
Systems (HDOS), Danbury, CT.
Data from the observatory, called the Advanced X-ray Astrophysics
Facility (AXAF), will be used to study X-ray radiation and is expected
to significantly improve scientific understanding of some of the most
energetic and violent processes in the universe. Launch of the AXAF is
scheduled for September 1998.
The observatory will produce picture-like images and spectrograms which
will yield information on temperature and chemical composition of the
objects it observes. Among the objects that will be observed are
neutron stars, black hole candidates, debris from supernova explosions,
quasars, the centers of active galaxies and hot gas in individual
galaxies and clusters of galaxies.
AXAF will produce spectrographic information about the temperature and
chemical composition of objects by separating the radiation received
according to wavelength, much as a prism splits visible light into
constituent colors. The observatory will produce 'picture-like' X-ray
images analogous to images in visible light made by traditional
telescopes. Once in orbit and operational, AXAF will provide
scientists with the most detailed views of the universe ever obtained
through observation of X-ray emissions.
The next step for AXAF is the precise alignment of the mirrors. The
first and largest pair of mirrors currently are being aligned in a
pathfinder mirror assembly at Eastman-Kodak Company (EKC), Rochester,
NY. After completion of this pathfinder alignment effort, the mirrors
will be shipped to Optical Coating Laboratory, Inc. (OCLI) in Santa
Rosa, CA, where they will be coated with iridium, returned to Kodak,
integrated and aligned into the High Resolution Mirror Assembly. The
remaining six mirrors for AXAF also will be coated at OCLI and sent to
EKC for assembly.
In 1996, all of the AXAF flight optics and detectors required to meet
the science mission objectives will be aligned and tested in the X-ray
Calibration Facility at Marshall.
AXAF is designed to be complementary to NASA's Great Observatories
already in orbit -- the Hubble Space Telescope launched in 1990, and
the Compton Gamma-Ray Observatory, launched in 1991. Each observatory
makes observations of stars, galaxies, and other astronomical objects
in distinct and separate wavelengths of energy, including visible
light, ultraviolet, gamma rays, and, in the case of AXAF, X-rays.
The AXAF development team consists of NASA, the Smithsonian
Astrophysical Observatory, TRW, HDOS, EKC and the Marshall Space Flight
Center, which manages the project for NASA's Office of Space Science,
Washington, DC.
///////////////////////////////////////////////////////////////////////////
(-09-) From: Bob Victor
Subject: Re: Skywatcher's Diary - February 1995
Date: Mon, 30 Jan 1995 11:14:41 -0500
OCCULTING VENUS: WHEN THE MOON GETS IN THE WAY, OR AT LEAST CLOSE
Mike Perry wrote:
> I've been told there was a phenomenon with the crescent moon
> in juxtaposition with the Planet Venus that is a fairly rare occurence.
> Could you give me more details? Jan. 27, 1995. Thanks.
In a posting to sci.astro.planetarium, you asked about the close
encounter between Venus and the Moon on the morning of Jan. 27, and
inquired about how often such encounters occur.
The encounter between Moon and Venus last Friday included an occultation
of Venus by the Moon visible from parts of southern Mexico, Central
America, and northern South America. From points farther north, including
the U.S., the Moon did not cover Venus, but instead, owing to the Moon's
parallax, appeared to pass narrowly to the south of Venus. It was clear
here in Michigan that morning, and the timing of the event allowed us to
view the closest approach of the two bodies in a dark sky, a spectacular
sight!
The only other occultation of Venus in 1995 will be from a portion of
the North Atlantic before sunup on May 27, and from Greenland, Iceland,
the British Isles, Europe except the SE, and N. Russia except the extreme
E. Unfortunately, it will be a daytime event for most locations. By the
time the Moon rises in North America that morning, the Moon will already
be to the east of Venus and moving away.
In 1996, on the evening of February 21, a spectacular occultation of
Venus will take place in Hawaii. North Americans will have to be content
with watching the Moon close in on Venus until moonset. Across the
Dateline in Indonesia, Australia, New Guinea, and the western Pacific
Ocean, the occultation takes place in daylight on Feb. 22.
[...]
Bob Victor
Abrams Planetarium
Michigan State University
East Lansing, MI 48824
USA
victor@pilot.msu.edu
///////////////////////////////////////////////////////////////////////////
(-10-) From: billa@netcom.com (Bill Arnett)
Subject: Re: Names for Months
Date: Thu, 19 Jan 1995 23:30:59 GMT
MOON MONTHS
This request may well belong in the folklore section, but perhaps someone on
this list may know the answer or where to find it. I saw somewhere a listing
of names given to the full moon for each month of the year. For example the
August full moon is called the grain moon or woodcutters moon.
Somebody posted this a few months ago: From the "Old Farmer's Almanac" 1994.
January Wolf Moon
February Snow Moon
March Worm Moon
April Pink Moon
May Flower Moon
June Strawberry Moon
July Buck Moon
August Sturgeon Moon
September Harvest Moon
October Hunter's Moon
November Beaver Moon
December Cold Moon
And of course when a month has two full moons the second is the Blue Moon!
///////////////////////////////////////////////////////////////////////////
(-11-) Carl Sagan vs. Immanuel Velikovsky
Cosmos fans, whether you're interested in the old PBS series or the study
of our place in the universe, might be interested in picking up a copy of
_Carl Sagan and Immanuel Velikovsky_, an expose of Sagan's critique of
Velikovsky's _Worlds in Collision_ book. This is a very controversial
issue, and the book provides some interesting insights into the scientific
community.
The book, written by Charles Ginenthal, "systematically examines each of
Sagan's scathing critiques in detail and dismisses them with a vast body
of evidence mainly gathered from the mainstream scientific literature,
including other work by Sagan himself," according to Washington Post
reviewer Martin Sieff.
Ted Holden wrote:
> Velikovsky was a friend of Albert Einsteins from the Prussian
> Scientific Academy, a student of Freud's, and an old-school academic
> who was researching a book dealing with one of Freud's favorite topics,
> i.e. a possible link between Oedipus and the Pharoah Akhnaton, when he
> discovered the same thing which Ignatius Donnelly had discovered almost
> 100 years earlier, i.e. that in sharp distinction from the scientific
> view that all change in biological and geological forms occurs slowly
> and over huge expanses of time, there appeared to be massive and valid
> evidence in ancient literature substantiating the ancient belief that
> the Earth had recently undergone a number of massive upheavals related
> to a final settling of the solar system intself into a stable
> configuration. He published a book called Worlds in Collision in 1950
> which became a runaway international bestseller under a MacMillan label
> for about seven weeks, at which point MacMillan was threatened with a
> continental boycott on all of its textbooks if they did not drop Worlds
> in Collision, and dropped it.
Sagan orchestrated much of the opposition agains Velikovsky's work.
Ginenthal's book is due out in March.
///////////////////////////////////////////////////////////////////////////
(-12-) P L A N E T A R I U M N E W S
This column will discuss the latest and greatest news for all the
planetarium mavens out there. If you have any, please send it to
vanhoose@lalaland.cl.msu.edu.
///////////////////////////////////////////////////////////////////////////
(-13-) From: Phillip F Schewe ,
American Institute of Physics
Subject: Superluminal Jets Illuminate Black Hole Research
PHYSICS NEWS UPDATE
SUPERLUMINAL JETS FROM AN OBJECT only 10,000 light years away in the
Milky Way may help astronomers to better understand the much bigger
jets shooting out of distant galaxies. First spotted by the Gamma Ray
Observatory in July 1994, the object GRO J1655-40 is probably a double-
star system. Matter from the lighter of the two stars is drawn away by
gravity onto an accretion disk closely surrounding the heavier (and
collapsed) companion, which is thought to be a neutron star or a
(few-solar-mass) black hole. One artifact of this process is the flaring
up of x rays and gamma rays from the much-heated disk. Indeed GRO
J1655-40 is at times the most powerful source of x rays and gamma rays
in the galaxy. Another artifact is the production of energetic radio-
emitting jets of material which project away from the core object
perpendicular to the plane of the disk. These jets appear to be
traveling at greater-than-light speeds. This is actually an optical
illusion owing to the alignment of the object relative to us, but it
does testify to the violent physics taking place in the core. Only one
other object in the Milky Way, GRS 1915+105, has been seen to have
superluminal jets, but the complex structure of GRO J1655-40 has been
mapped with greater resolution, in this case by the Very Long Baseline
Array of radio telescopes. One of the astronomers who spoke at last
week's astronomy meeting in Tucson, Robert Hjellming of the National
Radio Astronomy Observatory, called GRO J1655-40 an astronomical
"Rosetta Stone" because studies of the movement of individual blobs
within the jets (sometimes on a daily basis) may provide insights about
the energy mechanisms at work in the colossal extra-galactic jets
produced by presumed supermassive black holes.
///////////////////////////////////////////////////////////////////////////
(-14-) From: LABBEY@gitvm1.gatech.edu
Subject: Light Pollution Victory!
Date: Fri, 20 Jan 1995 01:11:25 EST
ONE-MAN LIGHT POLLUTION VICTORY
Atlanta Astronomy Club - a great example!
Congratulations to Tom Buchanan!
Tom Buchanan, chairman of our Light Pollution Committee, has accomplished an
unprecedented feat. He has written, and shepherded through to its final
enactment an ordinance prohibiting the construction of billboards with lights
pointed up toward the sky. Atlanta City Ordnance Z-94-39 was signed into law
by the mayor on the ninth of December. Very few cities, especially major
urban centers, have passed such a law.
Hopefully, Atlanta's light pollution will now begin a slow (maybe fast?)
decline. In the next few decades we should once again be able to see stars
fainter than third magnitude from close-in addresses.
This is a major accomplishment in our fight. Tom has had to oppose wealthy,
entrenched, commercial interests and bureaucracies. And he has done it with
almost no help. We owe a great debt to Tom for what he has done. What he has
done for us... and for our children and grandchildren.
///////////////////////////////////////////////////////////////////////////
(-15-) From: kdconod@delphi.com (Kevin D. Conod)
Subject: The Galaxy on its Side
Date: 17 Jan 1995 03:51:58 GMT
This is one of my favorite "neglected" items in astronomy, I've never
seen it any astronomy book. That the galactic equator is inclined to
the celestial equator by 62 degrees, and the ecliptic is inclined to
the celestial euator by 23.5 degrees is common knowlegde. But, here's
a better way to visualize it: (at this point it would help if you had
a star chart handy as you read this) The 'North Pole" of the Solar
System is at . . um, ha, I can't find the coordinates at the moment,
but it's in the constellation Draco, near the head. Now look at the
North Pole of the Galaxy (coordinates 12 hours, 51 min, and 27 degrees,
8 min North) it's in the constellation Coma Berenices. Now here's the
kicker: the direction in which the Solar System is travelling (this
point is known as the Solar Apex, coordinates 18.07 hrs, 30 deg) is in
the constellation Hercules, near the bright star Vega. Look how close
this is to the head of Draco (the North Pole of the Solar System)!!
This means that the Solar System is traveling through the Galaxy _on
its side_ towards Vega! Neat huh?
///////////////////////////////////////////////////////////////////////////
(-16-) From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Why Explore Mars?
Date: 31 Jan 1995 18:20:38 -0800
WHY SHOULD WE EXPLORE MARS?
Dr. Matthew Golombek, Mars Pathfinder Project Scientist
Mars is the most Earth-like of the five terrestrial planets and will be
the first other planet humans will visit. Why? The Moon and Mercury are
dry airless bodies. Venus has suffered a runaway greenhouse effect,
developing a very dense carbon dioxide atmosphere that has resulted in
the escape of all its water and uninhabitable surface temperatures of
750K. Mars, on the other hand, has everything necessary to support life,
including an atmosphere with polar caps and large amounts of water. Mars
is, in fact, the only other terrestrial planet with abundant water (and
liquid water is absolutely required for life as we know it). So
eventually humans will visit Mars not only because it is the only other
planet with reasonable surface conditions, but for the potential of what
it might become in the much more distant futureŅanother home for people.
Mars is also the only other place were we can begin to address the
question "Are we alone in the universe?" Is life a cosmic accident or
does life develop anywhere the proper environmental conditions are met?
A number of studies have shown that the likelihood of humans hearing
from possible advanced civilizations in other solar systems is extremely
remote given the enormous distances (and long time delays) involved.
Mars is our neighbor and, unlike any other planet in our solar system,
substantial evidence indicates that early environmental conditions may
have been similar to those on the young Earth. On Earth, evidence for
life can be found in some of the oldest rocks, dating from the end of
terminal bombardment around 4 billion years ago. Surfaces on Mars that
are of this age show remains of ancient lakes, implying that liquid
water was in equilibrium with the atmosphere at that time and that the
climate was both wetter and substantially warmer. If this is true, then
we can learn, through further exploration, whether life did develop on
Mars, or if not why not. If life did develop on Mars what has happened
to it, given that Viking found no evidence present-day life at the two
landing sites? We could even begin to explore whether life that began
early on could still survive in some specialized niches, such as
hydrothermal systems near volcanoes.
Finally, exploring Mars provides a way of better understanding
significant issues that face humankind in the future, namely the factors
involved in natural changes in a planet's climate. On the Earth, one of
the most important questions now being studied is whether or not humans
are contributing to global warming (if it is occurring via industrial
emissions). We do not know if we are, or if these changes could produce
negative environmental changes such as sea level rise due to melting of
the ice cap (most of the world's largest cities are at elevations very
close to sea level). Mars, on the other hand, provides a natural
laboratory for studying climatic changes on a variety of time scales. If
Mars was warmer and wetter with a thicker atmosphere in the past, why
did it change?
In addition, layered deposits near the martian polar caps suggest
climatic fluctuations on a shorter time scale. If we can learn the
important factors controlling climatic changes on another planet, we may
be better capable of understanding the consequences of human-influenced
changes on Earth. Lastly, Mars is an excellent laboratory to engage in
such a study, given that its geologic activity has produced rocks on the
surface of virtually all ages to study. Unlike the overactive Earth and
Venus, where most of the surface is covered by young rocks, and the
inactive Mercury and Moon, where only ancient rocks are present, Mars has
had an intermediate level of geological activity, which has produced
rocks on the surface that preserve the entire history of the solar
system. Sedimentary rocks preserved on the surface contain a record of
the environmental conditions in which they formed and thus any climatic
changes that have occurred through time.
///////////////////////////////////////////////////////////////////////////
(-17-) From: baalke@kelvin.jpl.nasa.gov (Ron Baalke)
Subject: Welcome to Mars!
Date: 31 Jan 1995 18:22:50 -0800
WELCOME TO MARS!
Donna Shirley, Mars Exploration Program Manager
NASA's Jet Propulsion Laboratory is going back to Mars for the first
time since 1976 with a small "fleet" of missions: orbiters, landers,
rovers, and maybe balloons and sample returns. And we are going in
partnership with other countries like Russia, France, Germany, Italy,
and Japan. Our plan is to fly at least two robotic missions to Mars
every opportunity (that is about every two years) from 1996 through
2005.
Robot spacecraft from the United States and Russia have been flying to
Mars since 1964. The last time we visited Mars with a fully successful
mission was with the Viking, which flew two orbiters and two landers in
1975 and 1976. The orbiters took pictures of the surface that were sharp
enough in some areas to see objects the size of a football field. The
landers took close-up images of two spots on the surface and did
experiments to search for life. While Viking did not find any life, the
possibility that life once existed on Mars is still there. But we now
know that finding evidence of life that exists now or in the past is
harder than we thought. Missions to Mars have been attempted since
Viking, but none have made all the scientific observations that were
planned.
On top of that, all the Mars missions that have so far flown have not
found out exactly what Mars is made out of. Do the rocks have carbon in
them? Oxygen? How much iron and aluminum? Another key question is:
Where did all the water go? Mars used to have a lot of surface water.
We know that because the orbiter pictures show river valleys and
channels. But it all disappeared a few billion years ago, except for a
little bit frozen into the polar ice caps. If people are ever to live
on Mars, we will need to find out if we can get water and other
materials from the Martian soil, air, or underground.
And we will have to answer these kinds of questions with a program that
costs much, much less than the previous Mars missions. For instance,
Viking cost, if we were buying it today, almost $4 billion. The first
two of our new missions, an orbiter and a lander, will cost less than
10% of that. And every two missions after that (which will fly to Mars
every two years) will cost less than 5% of the cost of Viking.
The Martian Chronicle will keep you posted on the work of the Mars
Exploration Program. We will tell you about our missions, what we hope
to find, and what we do find when we get there. And we will tell you
what is going to be happening and ways for you to get involved as we
build and fly our spacecraft. Other articles in the Chronicle will tell
you about our plans for educational outreach and public involvement.
Please e-mail me at donna.shirley@jpl.nasa.gov with your ideas on how
we can involve you and other people in exploring Mars.
///////////////////////////////////////////////////////////////////////////
(-18-) From: NasaNews
Date: Feb 7 20:46 UTC
Subject: Radar Studies Site in Cambodia
SPACE RADAR STUDIES ARCHEOLOGICAL SITE IN CAMBODIA
Images from the international Space Radar Laboratory (SRL) may help
researchers find previously unknown settlements near the ancient city
of Angkor in Cambodia.
The radar data was obtained during the October flight of NASA's Space
Shuttle Endeavour, processed and sent to the World Monuments Fund (WMF)
in January. The group had approached the radar science team about
observing the Angkor area after SRL's first flight in April 1994.
"I had read about the radar mission while the April flight was in
progress and instantly surmised that it would have applications to the
international research efforts at Angkor," said John Stubbs, program
director for the fund. "I didn't really know where to start, but I was
hopeful NASA would be willing to image the area around Angkor."
Angkor, a vast complex of more than 60 temples dating back to the ninth
century A.D., served as the spiritual center for the Khmer people. At
its height, the city housed an estimated population of one million
people and was supported by a massive system of reservoirs and canals.
The April flight of SRL's complementary radars, the Spaceborne Imaging
Radar-C/X-band Synthetic Aperture Radar (X-SAR), first demonstrated
their capability to obtain vast amounts of data applicable to
ecological, oceanographic, geologic and agricultural studies.
"We realized after the huge success of the first flight that we could
be more flexible in adding new sites to the timeline of flight two,"
said Dr. Diane Evans, the SIR-C project scientist at NASA's Jet
Propulsion Laboratory (JPL), Pasadena, CA. "Since our science team was
interested in studying as much of the tropical rain forest as possible,
Cambodia and the Angkor site seemed to be a great complement to our
ecology objectives."
Today, Angkor is hidden beneath a dense rain forest canopy. Its
temples have been ravaged by weather, war and looters. Its extensive
irrigation system has fallen into disuse.
"The radar's ability to penetrate clouds and vegetation makes it an
ideal tool for studying Angkor," Stubbs said. "I can see the
canal-and-reservoir system very clearly in the radar imagery, and
preliminary analysis reveals what may be evidence of organized
settlements of large tracts of land to the north of the present
archeological park, which until now, has gone unnoticed."
The SIR-C/X-SAR data will be used by the WMF, the Royal Angkor
Foundation and research teams from more than 11 countries to understand
how the city grew and then fell into disuse over 800 years.
"The 'temple mountain' monuments at Angkor, such as Angkor Wat and the
Bayon, are not unlike some of the pyramidal forms encountered in
Central America," Stubbs said. "The sheer size and sophistication of
Angkor's great city plan, now enveloped in dense jungle, sets this
ancient capital apart as the ultimate jungle ruin."
SIR-C/X-SAR is a joint mission of the United States, German and Italian
space agencies. JPL built and manages the SIR-C portion of the mission
for NASA's Office of Mission to Planet Earth.
NOTE: SIR-C/X-SAR radar images are available from JPL's public access
computer site, via Internet and the World Wide Web, at the address
http://www.jpl.nasa.gov, by anonymous file transfer protocol (ftp) at
the address jplinfo.jpl.nasa.gov, or by dialup modem to the telephone
number (818) 354-1333.
///////////////////////////////////////////////////////////////////////////
(-19-) SUBSCRIPTION AND OTHER PERTINENT INFORMATION
_The Armchair Astronomer_ is edited and distributed electronically on
a monthly basis or whenever possible by Todd E. Van Hoosear. This is not
an official publication of Michigan State University.
_The Armchair Astronomer_ compiles articles and commentaries on the study
of astronomy and its applications. Submissions and comments are welcome.
Please direct all subscription requests and article submissions to:
vanhoose@lalaland.cl.msu.edu.
When making any inquries related to this list, please preface your subject
with "ASTRO: " so I can easily spot list-related mail.
This compilation is copyright (c) 1995 Todd Ellis Van Hoosear. The editor
makes no claims to any individual articles printed herein and the authors
of any included articles retain full rights to their works. All copy-
righted works have been reproduced with permission of the copyright owner.
Permission is granted to reproduce and distribute individual articles of
this compilation unless otherwise stated. Please be sure to give the
original author credit for any reproduced works.
The most current issue of this publication is available for access via
HTML clients at URL: http://lalaland.cl.msu.edu/~vanhoose/astro/news.html.
If possible, individual articles will also be indexed at URL: http://lalaland.cl.msu.edu/~vanhoose/astro.html.
Back issues can be found at URL: http://lalaland.cl.msu.edu/~vanhoose/astro/newsMMYY.html
(".../news0195.html" for January 1995 for example).
News from NASA is brought to you by the Microwave Subnode of NASA's
Planetary Data System. Other news is compiled from posts to
sci.space.news, from Jonathan's Space Report (jcm@urania.harvard.edu),
and from other sources.
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