EAS BUSINESS…
March Recap
Keith
Allred from the SAS gave a comprehensive talk
on astrophotography and astro-imaging.
He covered techniques for a variety of imaging approaches, surveyed
types of cameras and CCD imagers, and showed a collection of images, including
some very large high-resolution color CCD images of deep sky targets.
Next EAS Meeting - Saturday April 21st At
Providence Pacific Clinic – 916 Pacific Avenue – 7:00 PM
The
April speaker is scheduled to be Bill O’Neil, who will discuss radio
telescopes, including videos of how radio telescopes work and provide
information not available to optical telescopes.”
Scheduled Meeting Topics:
Apr 21 –
Bill O’Neil, touring radio-telescope arrays
Apr 28 –
Astronomy Day (at the Library) - no meeting
May 19 –
Speaker not confirmed at press time
Member News
ASTRONOMY
DAY IS APRIL 28th 2001 !!!
Please
come and help out with Astronomy Day at the Everett library on Saturday April
28th.
If you haven’t already signed up, come join the rest of the EAS for a
fun day at the library. It is a good
way to meet new people interested in astronomy, get the word out about our
club, bring in new members, and spend one day
a year where your contribution is especially important toward making the EAS successful. Since some of our members are also involved
with other clubs in the area and their Astronomy Day events, we really need the
help from our remaining members. You
don’t need to be an expert astronomer, and we would really appreciate any help
you can provide. A chance at an eyepiece or similar door prize will
be provided to all library site participants and slide show presenters in
thanks for your contribution to Astronomy Day activities, to be drawn at the
end of the afternoon.
Report
on meteorite presentations at UW: Dr. Tony Irving and NASA Washington Space Grant organized a pair of presentations at
Johnson Hall, one by Dr. Michael
Zolensky, of NASA Johnson Space Center, that
discussed recent results of study of the Tagish Lake carbonaceous chondrite
that fell last year in British Columbia, and the recent discovery in January of
the second-largest lunar meteorite ever found.
The Tagish Lake material is some of the most pristine material ever
recovered from an observed fall, as it was kept frozen and handled carefully
from the time it fell on a frozen lake.
It is proving to be a very unique meteorite with unusual chemistry and
structure and an orbit that brought it from from the outer fringes of the main
asteroid belt. http://www.planetary.org/html/news/articlearchive/headlines/2000/yukonmetresult.html
The other
covered lunar meteorite NWA (Northwest Africa) 482 which is about 1 kilogram
(potato size) of lunar highland shocked anorothosite breccia found in Algeria
and purchased by American collector Mike Farmer for a consortium of meteorite
hunters, including the Hupe brothers here in Seattle. A large portion (3/4 lb.) of this extremely valuable ($5k/gm)
stone was on display at Johnson Hall, and Mike Farmer told the Indiana
Jones-like story of its recovery. Dr.
Don Brownlee and Dr. Tony Irving have conducted preliminary examinations, and
it is under study by other scientists as well. http://www.lunarrock.com/ and http://208.55.105.193/nwa482.htm
Cody Gibson has been hard at work, and our newly revamped web site is
about to make its appearance. Watch for
the URL.
Financial Health
The club maintains a safe $1150+ balance. We try to
keep approximately a $500 balance to allow for contingencies.
Club Star Party Info
Dates for
this season’s club star parties:
April 14 –
Ken & Judy Ward’s
April 27th – Astronomy Day Eve Star Party –
Harborview Park.
April 28th – Astronomy Day Star Party –
Harborview Park.
We try to hold
informal close-in star parties each month during the spring and summer months
on a weekend near the New moon at a member’s property or a local park. (call
Dave Mullen at (425) 347-3151 or club officers for info.) During the winter, phone tree is used to
arrange spur-of-the–moment events during clear weather spells when there are
significant celestial happenings.
Contact Dave Mullen for scope borrow
Club Scopes’ Status
Scope Loan
Status Waiting
10-inch
Dobsonian On loan No wait list
8-inch Dobsonian On
Loan No wait
list
60 mm Refractor Available No wait list
Astro Calendar
April 2001
Apr 01 - Asteroid 6
Hebe At Opposition (9.9 Mag.)
Apr 02 - Asteroid 13
Egeria At Opposition (10.1 Mag.)
Apr 06 - Asteroid 29
Amphitrite At Opposition (9.3 Mag.)
Apr 14 - Star Party
(Ward house) weather permitting
Apr 15 - Easter
Sunday
Apr 16 - Ast. 2
Pallas Occults TYC 1544-02005-1 (10.7 Mag.)
Apr 16-19 - AIAA
Gossamer Spacecraft Forum, Seattle, WA
Apr 21 - EAS Meeting
7:00 PM – Providence Hospital
Apr 22 - Lyrids
Meteor Shower Peak
Apr 23-29 - Astronomy
Week
Apr 27 - Moon occults Mu Geminorum (3rd
mag) 10:39 PM PDT
Apr 27 - Asteroid 18
Melpomene Opposition (10.4 Mag.)
Apr 27 - Astronomy Day Star Party #1 at Harborview Park
Apr 28 - Astronomy Day – Library and Harborview Park #2
Apr 29 - Asteroid 532
Herculina Opposition (9.0 Mag.)
May 2001
May 02 - Ast 271
Penthesilea Occults HIP 104276 (6.8 Mag star)
May 05 - Eta Aquarids
Meteor Shower Peak
May 07 - Mercury
Passes 4 Degrees From Saturn
May 08 - Asteroid 7
Iris At Opposition (9.5 Magnitude)
May 16 - Mercury
Passes 4 Degrees From Jupiter
May 17 - Saturn
Occults 93763 (7.7 Magnitude Star)
May 19 - EAS Meeting
7:00 PM – Providence Hospital
May 20 - Jupiter
Occults 76962 (7.0 Magnitude Star)
May 20 - Asteroid 15
Eunomia At Opposition (9.6 Magnitude)
May 22 - Mercury
Greatest Eastern Elongation (22 Degrees)
May 23 - Moon Occults
Saturn
May 24 - Moon Occults
Jupiter
May 28 – Memorial Day
Holiday (EAS meeting is previous week)
Over The Airwaves
"We
welcome a new writer, Rubie Johnson, to our group of radio script writers. With
EAS and SAS members Jim Ehrmin, Pat Lewis, Greg Donohue and Ted Vosk she is now
regularly writing and helping to produce our astronomy radio show, "It's
Over Your Head" on radio station KSER, FM 90.7. The six-minute segment is broadcast every Wednesday morning at
approximately 7:20 A.M. and gives a weekly look at what's up in the sky over
Snohomish County, with other information.
If you have a good idea for an astronomy broadcast or would like to try
your hand at writing a script, call Pat Lewis at (206) 524-2006 or email to
joagreen@aol.com If you are a
listener to the program, show your support by giving the program director of
KSER a call!" Web page with lots
of archives and other info is available at http://galaxyguy.bizland.com/radio_program.htm
KPLU
88.5 FM National Public Radio has daily broadcasts of "Star Date" by
the McDonald Observatory of the University of Texas at Austin, Monday through
Friday at 8:58 A.M. and 5:58 P.M. Saturday and Sunday). The short 2 minute radio show deals with
current topics of interest in astronomy.
The
University of Washington TV broadcasts programs from NASA at 12:00 AM Monday
through Friday, 12:30 AM Saturday, and 1:30 AM Sunday on the Channel 27 cable
station.
EAS Library – Book & Video List
The EAS has a library of books, videotapes, and software
for members to borrow. We always value
any items you would like to donate to this library. You can contact Scott Gibson to borrow or donate any materials.
MEMBERSHIP BENEFITS & INFORMATION
Membership in the Everett Astronomical Society (EAS) will
give you access to all the material in the lending library. The library, which
is maintained by Scott Gibson, consists of several VCR tapes, over 40 books,
magazines, and software titles.
Membership includes invitations to all of the club meetings and star
parties, plus the monthly newsletter, The Stargazer. In addition you will be able subscribe to Sky
and Telescope for $29.95 that
is $7 off the normal subscription rate, contact the treasurer for more
information. When renewing your subscription to Sky
& Telescope you should send your S&T renewal form along with a
check made out to Everett Astronomical Society to the EAS address. The EAS treasurer will renew your Sky and Telescope subscription for
you. Astronomy magazine ($29) offers a similar opportunity to club
members once a year in September.
EAS is a member of the Astronomical League and you will
receive the Astronomical League's newsletter, The Reflector. Being a member also allows you the use of
the club's telescopes, an award winning 10 inch Dobsonian mount reflector,
built as a club project or the 60mm refractor.
Contact Dave Mullen (425-347-3151) to borrow a telescope. EAS dues are $25. Send your annual dues to
the Everett Astronomical Society,
P.O. Box 12746, Everett, WA 98206.
Funds obtained from membership dues allows the Society to publish the
newsletter, pay Astronomical League dues and maintain our library.
OBSERVER’S INFORMATION…
Lunar Facts
Apr 01 First
Quarter Moon
Apr 07 Full
Moon
Apr 15 Last
Quarter Moon
Apr 23 New
Moon
Apr 30 First
Quarter
May 07 Full
Moon
May 15 Last
Quarter Moon
May 22 New
Moon
May 29 First
Quarter Moon
Digital Lunar
Orbiter Photographic Atlas of the Moon
The Lunar and Planetary Institute has created a digital
version of the Lunar Orbiter Photographic Atlas of the Moon, and Consolidated
Lunar Atlas available on the web at:
http://www.lpi.usra.edu/research/cla/menu.html
http://www.lpi.usra.edu/research/lunar_orbiter
Up In The Sky -- The Planets
MERCURY is hidden until May
VENUS is low in the east 45 minutes before sunrise.
MARS is high in the eastern sky before dawn (in
Ophiuchus). (magnitude -0.6)
rises in the southeast around 11:30 p.m. and shines in the south before and
during dawn. To its right is the much dimmer Antares (Rival of Mars). Mars is 12 arcseconds wide and will reach
21 arcseconds when nearest to Earth at opposition in June. You’ll want to start now and watch it grow,
and get your eye accustomed to the subtle details as they become visible.
JUPITER is to the left of Saturn, in the western sky in the
early evening and sinking toward sunset twilight.
SATURN is low in the western sky in the evening, shining at
magnitude 0.2.
URANUS and NEPTUNE are very low in the southeast before
dawn.
PLUTO is now high in the sky in Ophiuchus prior to morning
twilight. It is only a 14 magnitude
object, so good charts and a large telescope are necessary to see it.
Need
to know exactly what time the sun will set on Sept. 26, 2065? Or when it rose
in 565 BC? How about the length of daylight a week from Tuesday in Albuquerque,
N. M.? Just go to NOAA's solar calculator, now available on the Web. http://www.srrb.noaa.gov/highlights/sunrise/gen.html
International Space
Station – Visible Passes over Seattle
ISS Visibility – (note: times
may change due to maneuvers) http://spaceflight.nasa.gov/realdata/sightings/SSapplications/Post/SightingData/Seattle.html or also see link
http://www.heavens-above.com/PassSummary.asp?lat=47.979&lng=-122.201&alt=0&loc=Everett&TZ=PST&satid=25544
Constellation(s) of the Month
CIRCINUS:
The Compasses, as this Southern Hemisphere
constellation is also known, borders on the constellations of Apus, Centaurus,
Lupus, Musca, Norma, and Triangulum Australe, and ranks 16th in
overall brightness among the constellations, containing, ironically enough, not
a single one of the 200 brightest stars in all the constellations; it does however contain
10 stars brighter than magnitude 5.5.
Its central point is located at RA=14h,30m and Dec.= -62 degrees. It is completely visible from latitudes
South of +30 degrees, and completely invisible from latitudes North of +36
degrees. This constellation ranks 85th
in overall size, taking up only 93.35 square degrees, or 0.226% of the entire
sky. Circinus has, as stated, no bright
stars and no well known or named stars, and has no associated Messier objects
or meteor showers. Its solar
conjunction date is the 29th of October, and its midnight
culmination date is the 30th of April. Circinus was one of the 14 constellations invented by Lacaille
during his stay at the Cape of Good Hope in 1751-2.
TRIANGULUM
AUSTRALE: The Southern Triangle, as this
constellation is also known, borders on the constellations of Apus, Ara,
Circinus, and Norma. It ranks 14th in overall brightness among the
constellations, containing 12 stars brighter than magnitude 5.5; alpha, beta,
and gamma are its brightest stars, and Atria (alpha) is its only named star. Its central point is located at RA=15h,59m
and Dec.= -65 degrees. It is completely
visible from latitudes South of +20 degrees, and completely invisible from
latitudes North of +30 degrees. This
constellation ranks 83rd in overall size, taking up 109.98 square
degrees, or 0.267% of the sky.
Triangulum Australe has no known meteor showers, and no associated
Messier objects; it does have one included asterism however, which is known as
the “Three Patriarchs”. Its midnight
culmination date is May 23rd, and its solar conjunction date is
November 21st. This
constellation was first described by Italian Navigator Amerigo Vespucci in
1503.
Lacerta: This
interesting constellation, also known as “The Lizard”, borders on the constellations of Andromeda,
Cassiopeia, Cepheus, Cygnus, and Pegasus.
Its central point lies at RA=22h25m, and Dec. = +46 degrees. Lacerta is a small constellation, ranking 68th
in size among all the constellations.
It is completely visible from latitudes North of –33 degrees, and
completely invisible from latitudes South of –55 degrees. Its midnight culmination date is August 28th,
making it well placed for summer observing; it has 23 stars greater than
magnitude 5.5. Although it contains no
Messier objects and is not associated with any meteor showers, it does contain
a very unusual object which lies within its borders. This is BL Lac, originally believed to be a variable star. However it, and many others like it, are now
known to be very distant, and violently variable objects resembling quasars in
both size and energy output. They are
different from quasars however in that they appear to be related to distant
elliptical galaxies, and because their spectra show no discernable lines.
Young Astronomer’s Corner
ASTRONOMY DAY !!!!!!! : There will not be a
new column of information this month because of Astronomy Day. But it is important to know that Astronomy
Day is an excellent way for people of all ages to learn more about Astronomy,
and all the beautiful science and stellar and celestial objects it has to
offer. So come on down, and invite your
friends, family, and teachers, to the Everett Public Library on April 28th
for much astronomy “hands-on” fun, and to Harborview Park in Everett the
evenings of April 27th and 28th for telescope viewing,
weather-permitting. Learn many new
facts about the wonderful science and hobby of Astronomy! Hope to see you there!!!! Tune in next month for more Questions and
Answers for Young Astronomers, next time consisting of a continuation of
additional questions and answers about asteroids!
Astronomy and
Telescope “Lingo”
Astronomy
lingo: PSR: Prefix
used to designate a radio pulsar.
An example would be PSR 1913+16: these numbers represent the position of
the pulsar, in right ascension and declination.
Telescope
lingo: SUPER SCHMIDT TELESCOPE: An extreme form of
a Schmidt telescope (a catadioptric wide-field telescope) developed by James
Gilbert Baker in the late 1950’s, which employed additional correcting
plates. By adding these plates, Baker
was able to preserve the wide field, while augmenting the speed to focal ratios
approaching 0.5. Very fast cameras such
as these were used to record meteor and artificial satellite trails.
Astronomy Fun
Facts
Some “Astronomy Fun Facts” About the Early Universe:
** When the
Universe was one-hundredth of a second old, its temperature was approximately
100 billion degrees Celsius. At this
time, its radiation was also very thick: approximately 4 billion times the
density of the water we drink. The
difference between this early Universe density and the metallic element lead,
is in the same proportion as lead presently has to the vacuum in a standard TV
picture tube!
** The baby
Universe at 4 minutes was as dense as iron.
At 11 minutes, it was as dense as water; and at approximately 5 hours,
it was as dense as air. Now, several
billion years later, interstellar and intergalactic space is spread very, very
thin indeed. Were it not for a bit of
“clumpiness” in the region of our Galaxy (the Milky Way) in space, we would not
be here!!
** In the
beginning of the Universe, the temperature fell 99 billion degrees in just
about 3 minutes, or about 544 million degrees (36 times the temperature of the
Sun’s core) each second during this interval!
** When the
Universe was 9.6 million years old, it was undergoing expansion at about 1.98
million miles per second. Since this
velocity is about 10 times that of the speed of light, this signifies that
space, not actual matter, was doing the expanding. If an interplanetary probe were able to travel this fast to
Pluto, it would reach Pluto in less than a half-hour!!
“MIRROR”
IMAGES
“Mirror
Images” is a bi-monthly column, and was last published in March. It will resume next month. See you then!!
Astronomical Notes -- On & Off the Net...
Astronomers
have known for many years that stars form when the cores of giant clouds of
cold molecular material fragment and collapse. However, the details of the star
formation process are poorly understood. In particular, the smallest fragments
that can collapse to form very low mass stars or sub-stellar objects have not
yet been identified. Dr. Philip Lucas
and Dr. Patrick Roche controversially announced last year that they had
directly observed 13 faint points of light in Orion (a giant stellar nursery
where thousands of stars are being born) which appeared to have masses closer
to those of the giant planets -- a few times more massive than Jupiter in our
Solar System -- than the stars. The
same pair is announcing that they have confirmed their discovery of 'free
floating planets' in the Orion Nebula. Their measurements of the spectrum of
the infrared light from 20 objects in the Nebula show the characteristic
signature of water vapor. This confirms that these objects are indeed young,
low-mass bodies, and that the faintest of them are of planetary mass. These
planetary mass objects can only be seen because they are very young and still
warm after the process of formation.
Dr
Lucas commented, "It's exciting to find these planet-sized objects
floating around in space, unlike planets such as our Earth which orbit a star.
Our new results provide the first steps in the exploration of their physical
properties." "The
identification and study of these objects is extremely interesting in itself,"
added Dr. Roche, "but it can also aid our understanding of the star
formation process, which is one of the major mysteries in astronomy."
This
proof is sure to add fuel to the controversy of how such objects were born. Are
they actually planets, thrown out of their solar systems and now floating in
space, or have they been formed directly from a gas cloud in space, much like a
normal star is? There is also
controversy over how to classify these "in-between" objects. Some
astronomers say that as these may have been formed like a star, they should not
be called planets. The authors suggest that a new term -- planetars -- may be a
good compromise.
Finding
the evidence - Lucas and Roche were following up their discovery of these objects
last year, when they measured faint points of light in the Orion Nebula -- a
vast cloud of gas and dust that can be seen with the naked eye as the middle
'star' in the sword of the constellation of Orion. Their observations were made
in infrared light, using the United Kingdom Infrared Telescope at Mauna Kea
Observatory, Hawaii. This sparked a
wide controversy among scientists, with some arguing that the result was a
mistake because the planets might be normal stars far behind Orion and just
happened to look like very young planets.
Now
Lucas and Roche have used the same telescope to analyze the light from these
giant worlds at different frequencies and shown that they must be inside the
Orion Nebula. By studying the spectrum of the light from the planets, they were
able to measure the temperature of the objects, and then, with the use of
theoretical models, derive their masses.
The spectroscopic analysis shows strong absorption features due to water
vapor in the atmospheres of these objects, which shows that they are not hot
enough to be distant stars. The
results have been strengthened with the help of theoretical work on the
atmospheres by France Allard and Isabelle Baraffe of the Ecole Normale Superieure
at Lyon in France and by Peter Hauschildt at the University of Georgia in the
United States. Lucas, Roche, Allard and Hauschildt analyzed 20 of the brown
dwarfs and planet candidates in the Orion Nebula to confirm the result.
The so-called 'planets' float
in space by themselves, not orbiting any star. They are thought to be between 5
and 13 times as massive as the planet Jupiter, so they are rather large by the
standards of our Solar System and are most unlikely to support life. However, these worlds are not massive
enough to shine by nuclear fusion, the process that powers the Sun and the
stars. Nor are they massive enough for even the meager nuclear reactions that
occur in 'brown dwarfs', objects with masses between those of planets and
stars. The scientists admit that
there is a slight chance that they are misinterpreting the data. If all the
theoretical calculations for these poorly understood objects are wrong, or if
they are far older than the stars and brown dwarfs around them, there is an
outside chance that they are actually 20 or 30 times the mass of Jupiter -- too
big to be called planets. However, all the evidence found so far points to them
being free-floating planets, and other astronomers in Japan and Spain are
beginning to find signs of more and more planets in other nebulae like Orion.
http://www-astro.physics.ox.ac.uk/~pwl/trapl.jpg
http://www-astro.physics.ox.ac.uk/~pwl/trapl.gif
http://www-astro.physics.ox.ac.uk/~pwl/trapl.tif
NASA's
Hubble Space Telescope has seen a burst of light from an exploding star located much farther from Earth than any previously seen - a supernova blast in
the early Universe that is casting
light on a mystery of truly cosmic scale.
This stellar explosion is extraordinary not only because of its tremendous distance, 10 billion
light-years from Earth, but also
because its discovery greatly bolsters the case for the existence of a mysterious form of "dark energy"
pervading the universe. The concept of
dark energy, which shoves galaxies away
from each other at an ever-increasing speed, was first proposed, then discarded, by Albert Einstein early in the last century. The Hubble discovery also reinforces the startling idea
that the universe only recently began
speeding up. The discovery was made
about three years ago, when the unusually dim light of several distant supernovas suggested the universe is expanding more quickly than in the past. At
the time, there were several
explanations as to why this might be so,
including "dark energy". The more distant supernova
refutes the other alternatives and
offers the first tantalizing
observational evidence that gravity began slowing down the expansion of the Universe after the Big
Bang, and only later did the repulsive
force of dark energy win out over gravity's
grip.
"The
supernova appears to be one of a special class of explosions that allows astronomers to understand how the universe's expansion has changed over time,
much as the way a parent follows a
child's growth spurts by marking a doorway," said Adam Riess of the Space Telescope Science Institute (STScI). "This supernova shows us
the universe is behaving like a driver
who slows down approaching a red
stoplight and then hits the accelerator when the light turns green." The team of astronomers, led by Riess, made the discovery
by analyzing hundreds of images taken
by Hubble in infrared and visible light
to study how galaxies formed. Fortuitously, one of those galaxies contained a supernova previously discovered by
astronomers Ron Gilliland and Mark Phillips.
The
record-breaking supernova appears relatively bright, consequence of the Universe slowing down in the past (when
the supernova exploded) and
accelerating only recently. The reason
is that a decelerating universe holds galaxies relatively close together and objects in them would
have appeared brighter because they
would be closer. "Long ago, when the
light left this distant supernova, the universe appears to have been slowing down due to the mutual tug
of all the mass in the universe,"
said Riess. "Billions of years later, when the light left more recent supernovas, the universe had
begun accelerating, stretching the
expanse between galaxies and making
objects in them appear dimmer."
"Hubble's ability to find titanic stellar explosions at these extreme distances is what it takes to
confirm this theory that the universe
must have been slowing down before it switched
into high gear,'" said Dr. Anne Kinney, Director of NASA's Origins program at NASA Headquarters,
Washington, DC. "Later this
year astronauts will install a new camera on Hubble that will give us 10 times better resolution than
the current camera, which will give us
even better capability to find answers
to grand cosmic questions like this."
Observations of several
distant supernovas by two teams of
astronomers in 1998 led to the theory that the universe got the "green light" to accelerate
when it was half its present age.
Astronomers say the new Hubble findings rule out other explanations. Nearly a century ago, Einstein's Law of General Relativity concluded the universe must collapse under
the relentless pull of gravity.
However, like many scientists of his time, he
assumed the universe to be static and unchanging. To make his equations fit those assumptions, Einstein
added something he called the
"cosmological constant" whose gravity is repulsive, though he had no idea if it was real. Shortly afterwards, astronomer Edwin Hubble
made the celebrated discovery that the
universe was expanding. He assumed that
the universe must be slowing down under gravity and might even come to a halt, leading Einstein later to say that his cosmological constant was the
biggest blunder of his career. Now it
appears Einstein was on the right track after
all. The source of the
repulsive gravity may be something akin to
Einstein's cosmological constant -- referred to as the energy of the "quantum vacuum," a
subatomic netherworld pervading space
-- or it may be something entirely new and unexpected. "While we don't know what dark energy
is we are certain that understanding it
will provide crucial clues in the quest to
unify the forces and particles in the universe, and that the route to this understanding involves
telescopes, not accelerators,"
said astrophysicist Michael Turner of the
University of Chicago.
http://oposite.stsci.edu/pubinfo/pr/2001/09
A
novel telescope, buried deep in the Antarctic ice at the South Pole, has become
the first instrument to detect and track high-energy neutrinos from space,
setting the stage for a new field of astronomy that promises a view of some of
the most distant, enigmatic and violent phenomena in the universe.
Writing
in the March 22 edition of Nature, an international collaboration of physicists
and astronomers reports the first observation of high-energy neutrinos using
the AMANDA Telescope, a large array of buried detectors designed to detect the
fleeting signs of high-energy subatomic particles from the farthest reaches of
space. "We have proven the technique," says Francis Halzen, a
UW-Madison professor of physics and the lead author of the Nature paper. "We
have a unique probe with a sensitivity well beyond other experiments, and the
neutrinos we've seen are of a higher energy than has been seen before."
Neutrinos
are invisible, uncharged, nearly massless particles that can travel
cosmological distances. Unlike the photons that make up visible light, or other
kinds of radiation, neutrinos can pass unhindered through stars, vast magnetic
fields and entire galaxies without skipping a beat. To be able to detect high-energy neutrinos and follow their
trails back to their points of origin promises unparalleled insight into such extraordinary
phenomena as colliding black holes, gamma-ray bursters, the violent cores of
distant galaxies and the wreckage of exploded stars. Of all high-energy particles, only neutrinos can directly
convey astronomical information from the edge of the universe -- and from deep
inside the most cataclysmic high-energy processes, notes Robert Morse, a
UW-Madison professor of physics and the principal investigator for the AMANDA
project.
Sunk
more than one-and-a-half kilometers beneath the South Pole, the National
Science Foundation-funded AMANDA Telescope is designed to look not up, but
down, through the Earth to the sky in the Northern Hemisphere. Since neutrinos
can and do skip through the Earth continuously, it is the logical direction to
point the telescope in order to filter out other, confusing high-energy events.
The Earth between the detector at the South Pole and the northern sky filters
out everything but neutrinos. The
AMANDA telescope array consists of 677 optical modules, each the size of a
bowling ball, arrayed on electrical cables set deep in the ice beneath the
South Pole and arranged in a cylinder 500 meters in height and 120 meters in
diameter. The glass modules at the
heart of AMANDA work like light bulbs in reverse, capturing the faint and
fleeting streaks of light created when the occasional neutrino crashes head on
into another particle such as a proton. The subatomic wreck creates a muon,
another subatomic particle that, conveniently, traces an ephemeral trail of
blue light through the ice identical to the path of the neutrino. In theory,
that trail can be used to point back to the neutrino's point of origin. The
discovery of point sources of high-energy cosmic neutrinos is a long-standing
quest of modern astrophysics.
Cosmic
neutrinos are believed to be generated in the universe's most violent events --
exploding stars and active galactic nuclei, extremely violent and not-at-all
understood phenomena at the heart of many galaxies.
The results are based on
AMANDA observations of high-energy atmospheric neutrinos, neutrinos created
when cosmic rays crash into the Earth's atmosphere. While astrophysical in
nature, they are not the cosmic neutrinos coveted by scientists. Instead, they
simply prove that the AMANDA detector is a working neutrino telescope. "This paper establishes the AMANDA
experiment as a neutrino telescope," according to Albrect Karle, a
UW-Madison professor of physics and AMANDA scientist. "Now we can do
astrophysics." However,
while the new results from AMANDA represent a critical step toward establishing
a new field of astronomy, a much bigger detector is required, the Nature
paper's authors write, to search the sky for the speculated sources of the
cosmic neutrinos that constantly bombard the Earth. Toward that end, plans are
being made to construct a much larger detector know as IceCube. To consist of
4,800 optical modules on 80 strings, the IceCube detector would effectively
convert a cubic kilometer of Antarctic ice into the world's largest scientific
instrument. Still, the success of
AMANDA in detecting neutrinos at high energies effectively extends the reach of
conventional neutrino physics beyond any existing experiment and is a promising
step toward the 40-year-old dream of neutrino astronomy, says Morse, who has
spent the last decade overseeing the building of AMANDA. "This is our coming-out party,"
he says. "Now we start the process of discovery."
http://www.news.wisc.edu/misc/amanda.html
In
1998, NASA's Associate Administrator Wesley Huntress, Jr., stated, "Wherever
liquid water and chemical energy are found, there is life. There is no
exception." Could there,
then, be life on Mars? In the mid-1970s, the Viking Lander mission's Gas
Exchange Experiment detected strong chemical activity in the Martian soil.
Liquid water seems to be the one element needed for the equation of life on
Mars. The presence of water there, however, is still hotly contested. Many scientists believe that liquid water
does not and cannot exist on the surface of Mars today. Although surface water
may have been plentiful in Mars' past, they say, the current conditions of
freezing temperatures and a thin atmosphere mean that any water on Mars would
have to be deep underground. Moreover, if any water ice existing on Mars were
somehow warmed, it still wouldn't melt into water. The thin Martian atmosphere
instead would cause the ice to sublime directly into water vapor.
But
Dr. Gilbert Levin of Spherix, Inc., and his son, Dr. Ron Levin of MIT's Lincoln
Laboratory, believe differently. They say that liquid water-in limited amounts
and for limited times-can exist on the surface of present-day Mars. They have
based their theory on data collected from the Viking landers and on the 1997
Mars Pathfinder mission. This
father-son team has suggested a diurnal water cycle on Mars: water vapor in the
air freezes out by night, then during the day the ice melts. As the day
progresses, the heat of the Sun causes this liquid water to evaporate back into
the air. It has already been
established from Viking photographs that a thin frost does form overnight on
certain areas of the Martian surface. Unlike many scientists, the Levins
believe that this frosty layer does not instantly revert back into water vapor
when the Sun rises. They suggest that, in the early hours of the Martian
morning, the atmosphere more than one meter above the Martian surface remains
too cold to hold water vapor. So the moisture stays on the ground.
Data
from the Mars Pathfinder support this theory, as the Pathfinder temperature
readings noted that temperatures one meter above the surface were often dozens
of degrees colder than the temperatures closer to the ground. This layer of cold air, say the Levins,
provides a form of insulation, trapping the water moisture below. Since the
atmosphere is too cold to hold the water as vapor and the ground is warm enough
to melt the ice, the water melts into a liquid. This liquid water, the Levins
believe, remains on the surface until the temperature of the atmosphere rises
enough to allow the water to evaporate. In this way, they argue, the Martian
soil becomes briefly saturated with liquid water every day. "The meteorological data fully
confirm the presence of liquid water in the topsoil each morning,"
says Gilbert Levin. "The black-and-white as well as the color images
show slick areas that may well be moist patches."
Such
a scenario is certainly possible, admits Christopher McKay. McKay is a
planetary scientist at NASA Ames Research Center in Mountain View, CA, and a
member of the NASA Astrobiology Institute.
"At the surface the frost may melt to form a very short-lived
layer of liquid," says McKay. "The experiments show that this
is the case." But, he cautions, "how long it persists is not
yet accurately determined. There have
been several attempts to look at the problem of frost evaporation and melting
on Mars theoretically," says McKay. But Levin's analysis, he says, is
"badly flawed. The way to address this question," he says,
"is with experiment."
The
Levins look to tests conducted in Death Valley, CA, for support of their
theory. Soil samples taken from the top one to two millimeters of the
Californian sand dunes and analyzed by soil scientists from NASA's Jet
Propulsion Laboratory were reported to contain 0.9% moisture, comparable to the
moisture levels found in the Martian soil by the Viking mission. These desert samples from California also
contained aerobic microorganisms. No clear evidence has yet been found,
however, that there is life in the topmost layer of the Martian soil. Mars may, indeed, contain such forms of
microorganic life. The Levins point to a study published in the Federation of
European Microbiological Societies Reviews in 1997 by Elena Vorobyova, et al.,
entitled "The Deep Cold Biosphere: Facts and Hypothesis." This study
reported that permafrost conditions provide a constant and stable environment
to permit microbial communities to survive for millions of years.
The
Levins cite this research as direct evidence for adaptive physiological and
biochemical processes in microorganisms during long exposure to cold. While
these findings refer to terrestrial microorganisms, the Levins believe they
might also apply to Mars. McKay does
not believe these analogies to terrestrial environments prove anything about
Mars, however. "Mars is still much drier and much colder than even the
Atacama Desert in Chile or the dry valleys of Antarctica," argues
McKay. "And Death Valley is not that dry. It rains there 25 millimeters
a year."
Gilbert
Levin is a long-time proponent of life on Mars. He worked on the Viking
missions in the mid-1970s and steadfastly believes that the Viking Lander's
Labeled Release (LR) experiment proved that primitive life does exist on
present-day Mars. The LR experiment
dropped liquid nutrient into a sample of Martian soil, then measured the gases
that were released by the mixture. If Martian bacteria had consumed the
nutrients and had begun to multiply, certain gases would have been released.
When the LR experiment was conducted on both Viking Landers, some of the gases
emitted seemed to suggest that microbes were ingesting the released nutrients.
But, overall, the results were ambiguous.
Many in the scientific community believe that the LR results can be
explained non-biologically. One such explanation is that the LR experiment
showed the surface of Mars to contain oxides. When the nutrients mixed with the
oxides, a chemical reaction-not a biological one-occurred. Moreover, these
oxides would actually prevent life from forming on the Martian surface. Gilbert Levin isn't swayed by this
reasoning. After examining all the non-biological possibilities and looking at
the new findings about life in extreme environments on Earth, Levin now firmly
believes that the LR experiment did find microbial life on Mars. His new model for the formation of liquid
water, he argues, "removes the final constraint preventing acceptance
of the biological interpretation of the Viking LR Mars data as having detected
living microorganisms in the soil of Mars. It comes at a time when a growing
body of evidence from the Earth and space are supporting the presence of life
not only on Mars, but on many celestial bodies."
For
McKay, the Viking experiments do not prove-or even suggest-that life could
exist on the surface of Mars. "I support a chemical explanation for the
Labeled Release experiment and the other Viking instruments, such as the Gas
Chromatograph/Mass Spectrometer and the Gas Exchange experiment," he
says. The Gas Chromatograph/Mass
Spectrometer (GCMS) was designed to measure organic compounds in the Martian
soil. Organic compounds are present in space (for example, in meteorites), but
the GCMS found no trace of them on the surface of Mars. Gilbert Levin believes,
however, that the GCMS instrument sent to Mars could easily have missed
biologically significant amounts of organic matter in the soil, as it had in a
number of tests on Earth.
The
Gas Exchange (GEX) experiment submerged a sample of Martian soil in a nutrient
mixture, and incubated the soil for 12 days in a simulated Martian atmosphere.
Gases emitted by organisms consuming the nutrients would have been detected by
the gas chromatograph. While the GEX
experiment did detect some gases, it also got results with the control
sample-soil that had been heated to sterilize it of any possible life. In other
words, non-biological processes may have been at work. Subsequent laboratory
experiments on Earth demonstrated that similar results were obtained when water
was added to highly-reactive oxidizing compounds, such as the oxides or
superoxides now believed to be present in Martian soil. "A biology explanation [for the
Viking test results] is inconsistent, ecologically, with what we know about
Mars' surface environment," says McKay.
What Next? - In 2003, NASA
will send two rovers to Mars to hunt for signs of water in the rocks and
surface soil. In the same year, the European Space Agency will launch Mars
Express, which will include a lander. The Lander, dubbed Beagle 2, will contain
a scientific payload dedicated to detecting signs of biogenic activity on
Mars-the first such payload to be sent to Mars since Viking.
http://nai.arc.nasa.gov/index.cfm?page=liquid_water
Radiation
belts very close to Jupiter would zap any future spacecraft there even more
severely than previously estimated, new measurements by NASA's Cassini
spacecraft indicate.
The
harshest radiation is within about 300,000 kilometers (about 200,000 miles) of
the giant planet, closer in than NASA's Galileo orbiter has yet ventured and
safely 300 times closer than Cassini's nearest approach when it passed Jupiter
three months ago on its way to Saturn.
Cassini's
Italian-made main antenna, through which the craft communicates with Earth and
will radar-map Saturn's moon Titan, was used during the Jupiter flyby in a
listen-only mode, pointed toward Jupiter. It caught details of the radiation
belts' natural radio emissions not discernible from Earth or any earlier
spacecraft, said Dr. Michael Janssen, team leader for the radiometer
instrument. The quality of results is encouraging for radar research at Saturn,
he said.
"We
got some surprises," said Dr. Scott Bolton, a physicist for NASA's Jet
Propulsion Laboratory, Pasadena, Calif. "This has implications not only
for understanding the physical processes in the radiation belts, but also for
designing any spacecraft for future exploration close to Jupiter."
High-energy
electrons, traveling at nearly the speed of light in spirals shaped by the
magnetic field enveloping Jupiter, beam out radio emissions called synchrotron
radiation. Synchrotron radiation is not the type that could damage spacecraft,
but it provides information about the high-energy electrons emitting it, which
are the potential hazards.
Earth-based
radio telescopes have mapped some wavelengths of synchrotron emissions from
Jupiter's radiation belts, and scientists have used that information to model
the belts and estimate their potential to damage spacecraft. But the shortest
wavelengths, emitted only by the highest-energy electrons in the belts, get
lost in hundred-fold stronger, non-synchrotron radio emissions from heat in
Jupiter's atmosphere.
As
it flew past Jupiter, Cassini had a better angle for distinguishing atmospheric
emissions from radiation belt emissions, though the task was still challenging.
The craft had to rock back and forth to scan across the target area several
times, then roll 90 degrees and scan back and forth again, to recognize the
synchrotron radiation by its trait of polarization.
"Cassini,
with its fabulous antenna, has been able to anchor the high-energy end of the
electron spectrum from Jupiter's radiation belts for the first time,"
Bolton said.
Concurrent
Earth-based measurements of radio emissions from Jupiter added context for
interpreting the Cassini radiometric measurements. Scientists took readings at
several wavelengths using the National Science Foundation's Very Large Array of
radio telescopes near Socorro, N. M. And students at 25 middle schools and high
schools in 13 states used a large dish antenna near Barstow, Calif., by remote
control from their classrooms to monitor changes in Jupiter's emissions from
week to week. The students' work, coordinated by a partnership of JPL's Deep
Space Network and the Lewis Center for Educational Research, Apple Valley,
Calif., helped rule out the possibility that Cassini's measurements happened to
be made when emission levels were either unusually high or unusually low.
Cassini's
measurements indicate that the highest-energy electrons are sparser than
anticipated. That's not good news for spacecraft designers, though. Explaining
the known levels of longer-wavelength synchrotron radiation without having as
many of the highest-energy electrons as expected means estimates must be
increased sharply for the number of electrons with slightly lower energy
levels. Those electrons are still plenty energetic enough to fry electronic
equipment. The increase in their numbers is many times greater than the
decrease in numbers of highest-energy electrons, compared to the earlier
estimates, so the net result is a more hazardous environment than previously
estimated, Bolton said.
No
approved NASA missions are currently planned for venturing as close to Jupiter
as the region with the heightened estimates of radiation hazard, he said. The
moon Europa, target of NASA's next planned mission to the jovian system, is
about twice as far from planet. Europa is nevertheless in a hazardous enough
radiation environment that the Europa Orbiter mission is being designed with
substantial shielding and durable electronics. The new measurements by Cassini
carry direct implications for potential closer-in exploration, such as
Discovery mission proposals for orbital studies of Jupiter's atmosphere and
internal structure. The only
spacecraft that has experienced the full blast of the radiation belts so far is
the Galileo atmospheric probe, which passed through them quickly before
plunging into Jupiter's atmosphere in 1995. The Galileo orbiter, which released
that probe, will end its seven-year tour around Jupiter with a dive into the atmosphere
in 2003. It has already endured more
than three times the radiation exposure it was built to withstand.
The
recent radio observations help with understanding how Jupiter's radiation belts
work, as well as what hazards they present, Bolton said. "We would like
to know more about their potential interactions with the atmosphere and with
the rings," he said. Jupiter's radiation belts provide a useful
comparison for better understanding of Earth's radiation belts, too..
One
of the most perplexing problems facing astronomers is the identity of the
mysterious "dark matter" that seems to pervade the Universe. Evidence suggests that the mass of most
galaxies is dominated by dark matter. As it is dark, it is impossible to detect
by conventional astronomical means, and so its nature and distribution remains
unknown. One of the principal
theories for the dark matter in galaxies is that it comprises small, dim
objects known as Massive Compact Halo Objects (MACHOs). These might be dim
stars such as white dwarfs, "failed stars" known as brown dwarfs, or
even black holes. Dr. Wyn Evans
(Oxford University) announced the latest results of a search for dark matter in
the neighboring spiral galaxy of Andromeda.
MACHOs
in Andromeda
Dr.
Evans is a member of an international team from Oxford, Cambridge, London and
Paris universities who are
participating in an ambitious new survey of the giant Andromeda galaxy. Since 1999, this galaxy has been monitored
four times a night using the Isaac Newton Telescope in La Palma. By comparing
the galaxy night after night, all sorts of variable sources are discovered --
including pulsating stars, exploding stars and, rarest of all, microlensing
events. Microlensing occurs when light
traveling towards Earth is deflected by the presence of an intervening mass.
When a dark object crosses the observer's line of sight, it causes
characteristic variations in the light from background stars -- just as if a
glass lens was being used. This microlensing enables astronomers to detect dark
objects like MACHOs in other star systems.
Very
recently, the survey team has announced the discovery of a short duration
microlensing event towards the Andromeda galaxy. As stars in Andromeda are
(mainly) unresolved into individual points of light, the event has been
detected by following the flux associated with a pixel (a single picture
element), rather than a source star.
"This is the ULTIMATE in scientific detection," said
Dr. Evans, "as not merely is the lens dark and unseen, but the source
is indistinguishable from the other tens of thousands of stars on the pixel." This microlensing event is one of the very
first seen in an external galaxy. It is situated far from the center of the
Andromeda galaxy, outside the stellar bulge. It also has a very short duration,
under two days. The interpretation of
this event raises a number of interesting possibilities. First and most
exciting, the dark object could be a brown dwarf ("failed star") in
the outer parts of the Milky Way Galaxy or in the Andromeda Galaxy. If so, then
astronomers have discovered an object that gives out almost no light and is
some 2 million light years away, a thousand times more distant than any other
known brown dwarf. The other possibility
is that the dark object could be a low mass star in the disk of the Andromeda
galaxy.
The search for further
microlensing events during this survey of Andromeda will continue for at least
three years in total. The distribution of such events will then enable
astronomers to work out what fraction of the dark matter halo of the Andromeda
galaxy is composed of MACHOS, as well as their characteristic mass.
http://www.point-agape.org
Asteroid
search efforts got a boost from a new, improved camera installed this week for NASA's Near Earth Asteroid Tracking system on the 1.2-meter (48-inch)
Oschin telescope at the Palomar
Observatory near San Diego, Calif.
The camera has a new three-eyed design with three lenses. It can provide three times more data and
survey 1.5 times more sky than the
present NEAT camera that operates currently at
the Maui Space Surveillance Site's 1.2-meter (48-inch) telescope in Hawaii.
"The
new camera has the flexibility to do a wide and shallow sky survey, or one not-so-wide but deeper," said
Dr. Steven Pravdo, NEAT project manager
at NASA's Jet Propulsion Laboratory,
Pasadena, Calif. "We plan to do more deep observing, so that we can see as many objects as possible." The asteroid observers will be able to take
panoramic views of the sky with the
three camera eyes or to take a deep exposure
showing many faint objects in a narrow swath.
The
whole control system on the Oschin telescope was upgraded to a computer-controlled system. The old manual system pointed to only 10 positions each
night, but the camera now needs to
point to different positions 1,000 times a night. The new system captures about 3.75 square degrees of the sky per image, hundreds of square degrees per
night, and most of the accessible sky
each month. The NEAT team can operate
the telescope from their desks at JPL,
as though the camera were a spacecraft.
The
new NEAT camera takes pictures with 48 million
pixels, three times more than the system it replaced, and it can see fainter objects. The Palomar staff,
headed by Superintendent Bob Thicksten,
has helped with the improvements.
Palomar Observatory is a facility of the
California Institute of Technology.
"This
will be a new lease on life for a very famous
survey telescope, which conducted the first comprehensive survey of the northern skies in the 1950s
and which is now targeting some
exciting astronomical goals - searching for
near-Earth asteroids and examining supernovae and their role in determining the fate of the cosmos,"
said Richard Ellis, the director of
Palomar Observatory. The new camera's
installation closes the era of using
photographic plates, and marks the rebirth of Palomar Observatory's Oschin telescope in the
electronic age. "It has been a
dream 20 years in the making," says NEAT's principal investigator Eleanor Helin, who has been
discovering asteroids from Palomar's
two wide-field telescopes since the early days
of near-Earth object search.
This new camera system will
continue NASA's effort to find 90
percent of all large, near-Earth asteroids by 2010. "We installed the camera on April 9th, and hope to get
results in the next few days,"
Pravdo said. Using the data taken by
the NEAT camera, the Nearby Supernova
Factory project by the Lawrence Berkeley National Laboratory will find exploded stars in nearby galaxies. "The same data we use to find objects close to
Earth, they will use to find objects
very far away," said Pravdo.
NEAT http://neat.jpl.nasa.gov
Near-Earth objects http://neo.jpl.nasa.gov
On
rusty-red Mars, a curious deposit of gray-colored hematite (a mineral cousin of
common household rust) could hold the key to the mystery of elusive Martian
water. Scientists think Mars has a bad
case of rust. Martian soil is full of iron-bearing compounds that, over the
eons, have reacted with trace amounts of oxygen and water vapor in Mars'
atmosphere to form iron oxide -- the same chemical that covers innumerable
rusty nails in garages and workshops on Earth. The word "rust" conjures up images of things that are
red --like Mars and old nails-- but not all iron oxide is the same color. Here
on Earth a gray-hued variety of iron oxide, a mineral called hematite, can
precipitate in hot springs or in standing pools of water.
Gray
hematite is not the sort of rust you might expect to find on a desert-dry
planet like Mars. But perhaps Mars wasn't always as dry as it is today. There
are many signs of ancient or hidden water on the Red Planet including
flash-flood gullies, sedimentary layers ... and hematite. In 1998, an infrared spectrometer on NASA's
Mars Global Surveyor (MGS) spacecraft detected a substantial deposit of gray
hematite near the Martian equator, in a 500 km-wide region called Sinus
Meridiani. The discovery raised the tantalizing possibility that hot springs
were once active on Mars. "We
believe that the gray hematite is very strong evidence that water was once
present in that area," said Victoria Hamilton, a planetary geologist
at Arizona State University (ASU). "We think the deposit is fairly old.
It was buried, perhaps, for several hundred million years or more and now it's
being exposed by wind erosion."
Gray
hematite has the same chemical formula (Fe2O3) as its rusty-red cousin,
but a different crystalline structure. Red rust is fine and powdery; typical
grains are hundreds of nanometers to a few microns across. Gray hematite
crystals are larger, like grains of sand.
"Red and gray iron oxides on Mars are really just different
forms of the same mineral," explained Hamilton. "If you ground
up the gray hematite into a fine powder it would turn red because the smaller
grains scatter red light."
The coarse-grained structure of gray hematite is important, says ASU's
Jack Farmer, head of the NASA Astrobiology Institute's Mars Focus Group,
because "to get that kind of coarsening of the crystallinity, you would
need to have a reasonable amount of water available" where the
hematite formed. The link between
water and gray hematite makes the so-called "Hematite Site" (Sinus
Meridiani) an alluring target for future Mars landers as well as for remote
sensing instruments on the 2001 Mars Odyssey spacecraft -- launched in early
April 2001.
Odyssey
carries an infrared imaging camera called THEMIS (short for Thermal Emission
Imaging System) that can identify surface minerals from orbit by analyzing
their spectral "fingerprints."
"It turns out that all materials vibrate at the atomic scale,"
explains Hamilton. "For minerals, the rate at which the atoms vibrate
corresponds to the thermal infrared part of the electromagnetic spectrum,
between about 5 and 50 microns. Those are longer wavelengths than what our eyes
can see." Every mineral has a unique infrared spectrum that identifies
it as surely as the fingerprints of a human being, she added. THEMIS is a "next-generation" instrument
that can capture sharper images than TES, the Thermal Emission Spectrometer
that is orbiting Mars now aboard Mars Global Surveyor. THEMIS will be able to
discern the mineral content of geological features only 100 meters across,
compared to 3 km for TES.
Of
many candidate landing sites for NASA's 2003 Mars Exploration Rovers, the Sinus
Meridiani region is one of the most intriguing to scientists. THEMIS data could
help planners pinpoint the best places to land, especially if the maps reveal
deposits of other aqueous minerals such as carbonates or sulfates. "The interesting thing about
carbonates and sulfates," says Phil Christensen, principal investigator
for THEMIS, "is that these materials can be better (than hematite) at
preserving a fossil record. Some of them, like carbonates, would also indicate
that standing bodies of water were present on the surface." Hematite
minerals, on the other hand, might have been formed by hydrothermal water deep
underground. So far, instruments on
MGS have found no direct evidence for carbonates or sulfates anywhere on Mars.
The absence of such aqueous minerals is a mystery if liquid Martian water -- in
the form of lakes, rivers or oceans -- was indeed abundant in the planet's
geological past.
Christensen
cautions that the spatial resolution of TES on Mars Global Surveyor might not
have been good enough to detect small deposits of carbonates. With its superior
resolution, THEMIS has a better chance. For example, TES would not have
detected the carbonate layers in Earth's Grand Canyon, but THEMIS would. Until someone finds signs of carbonates or
sulfates on Mars, perhaps in some future THEMIS image, gray hematite remains
the best known mineral signpost for ancient Martian water. The hematite makes scientists wonder, was
there once a Martian equivalent of Yellowstone National Park where steaming hot
springs formed hematite-laden pools? And are underground springs still present
there today? Human exploration of the Red Planet could hinge on the answers.
And there may be no better place to find out than Sinus Meridiani, where the
lure of hematite is powerful indeed.
FROM THE EDITOR'S TERMINAL
The Stargazer is your newsletter
and therefore it should be a cooperative project. Ads, announcements, suggestions, and literary works should be
received by the editor before the 1st of the month of publication, for example,
material for May's newsletter should be received May 1st. If you wish to contribute an article or
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