Sky & Telescope’s News Bulletin 25 Jan 2002
For images and Web links for these items, visit http://www.skypub.com
MICROBIAL NICHES
The discovery of a unique population of microbes deep within the Earth
has bolstered the plausibility that life exists elsewhere within our
solar system. The microbes, reported in the January 17th issue of the
journal Nature confirm that life can exist with neither sunlight nor
any influx of organic materials.
Frank Chapelle (U.S. Geological Survey) and Derek Lovley (University
of Massachusetts, Amherst) discovered an ecosystem almost completely
dominated by methanogenic archaea, an ancient form of bacteria that
use hydrogen released by geothermal activity as an energy source. The
community, located approximately 200 meters underground in Idaho,
feeds exclusively off the hydrogen from a hot spring. There is no
sunlight available for photosynthesis, and no carbon-based food
sources.
The water from the hot spring bubbles through a layer of volcanic ash
laid down 4 million ago during an eruption of Mount Kilgore, at the
southern tip of the Beaverhead Mountain range. The ash was heated to
800-900 deg. Celsius by the eruption, vaporizing all organic carbon
and leaving "volcanic tuff" devoid of organic material. The lack of
available organic material is what sets this microbial community apart
from others.
Almost every ecosystem on Earth receives some input from the Sun,
either directly by photosynthesis or indirectly from organic material
generated by photosynthetic organisms. Archea are present in the
communities that surround deep ocean vents, but they are out-competed
by more efficient bacteria that live on an input of organic material.
"Most natural microbial communities reflect this photosynthetic bias,"
said Chapelle. But the lack of sunlight and organic material around
the hot spring allows the archaea to dominate. "If you think about it,
these conditions would be an awful lot more ‘normal’ throughout the
solar system."
Ecosystems that do not require sunlight give researchers hope that
life could exist on Europa or under the Martian surface. If Europa
does turn out to have a liquid ocean under of icy crust, a community
of archaea-like organisms could exist, provided that some form of
geothermal activity was present under the ice. With just hydrogen,
water, and CO2, archaea can thrive.
Astronomers selecting candidate sites with these ecosystems in mind
would simply have to look for a source of hydrogen along with water.
"Where that hydrogen comes from doesn’t matter to the microorganisms,"
said Chapelle.
ASTRONOMY OUTREACH SURVEY ONLINE
The Astronomical Society of the Pacific (ASP), along with the
Astronomical League (AL), put out a call to anyone who has taught or
plans to teach astronomy to the general public. In an effort to better
equip and enable both formal and informal astronomy educators, the ASP
and AL have created an online survey to collect information on the
current state of astronomical outreach — the ultimate goal being to
improve the public’s understanding and appreciation the heavens.
"Hundreds of amateur astronomers in the United States have conducted
public outreach to schools, scout groups, churches, and other
organizations. Most have never had the benefit of having anyone help
them put together a presentation package for outreach activities. The
ASP’s project will help us provide such assistance," said Barry
Beaman, past president of the AL and current AL liaison to the ASP, in
a prepared statement.
The survey takes about 10 minutes to complete and can be found on the
ASP home page at
http://www.astrosociety.org/education/astronomer-survey.html .
THIS WEEK’S "SKY AT A GLANCE"
Some daily events in the changing sky, by the editors of Sky &
Telescope.
JAN. 27 — SUNDAY
* The Moon shines well below bright Jupiter this evening. Closer to
the Moon’s upper left are Pollux and, a little higher, Castor. Later
at night they’re lined up directly above the Moon.
* Jupiter’s moon Io reappears from eclipse out of Jupiter’s shadow
around 11:21 p.m. Eastern Standard Time. A small telescope will show
Io swelling into view just off Jupiter’s eastern limb.
JAN. 28 — MONDAY
* Full Moon (exact at 5:50 p.m. EST).
* Jupiter’s moon Io casts its tiny black shadow on the planet from
6:13 to 8:28 p.m. EST. This is the first of three moon shadows that
will cross Jupiter in the next three evenings at good times for
telescope users in most of the Americas.
* Jupiter’s Great Red Spot should cross Jupiter’s central meridian
(the imaginary line down the center of the planet’s disk from pole to
pole) around 10:09 p.m. EST. The "red" spot is very pale orange-tan.
It should be visible for at least 50 minutes before and after in a
good 4- or 6-inch telescope if the atmospheric seeing is sharp and
steady. Our complete list of Red Spot transit times, at
http://www.skypub.com/sights/moonplanets/redspot.html , is good
worldwide.
JAN. 29 — TUESDAY
* Ganymede, Jupiter’s largest moon, crosses the planet’s bright face
this evening from 6:28 to 9:30 p.m. EST. Much more easily visible is
Ganymede’s black shadow, which crosses Jupiter from 9:15 p.m. to 12:21
a.m. EST.
JAN. 30 — WEDNESDAY
* Callisto casts its shadow on Jupiter from 6:00 p.m. to 9:02 p.m.
EST. A list of all of Jupiter’s satellite phenomena such as this, good
worldwide, appears in Sky & Telescope’s Celestial Calendar section
each month.
* Jupiter’s Red Spot transits around 11:47 p.m. EST.
JAN. 31 — THURSDAY
* Jupiter’s Red Spot transits around 7:38 p.m. EST.
FEB. 1 — FRIDAY
* Go out around midnight and you can get a taste of springtime
stars. You’ll find the waning gibbous Moon shining in the east with
bright Arcturus well to its left. Spica shines roughly half as far
below the Moon. High in the northeast is the Big Dipper. High in the
southeast, far to the Moon’s upper right, is Leo.
FEB. 2 — SATURDAY
* Jupiter’s Red Spot transits around 9:16 p.m. EST.
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THIS WEEK’S PLANET ROUNDUP
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MERCURY and VENUS are hidden in the glare of the Sun.
MARS (magnitude +1.0, in Pisces) is the brightest "star" in the
southwest during twilight, glowing orange. It sinks lower in the
west-southwest later in the evening and sets around 10 p.m.
JUPITER (magnitude -2.6, in Gemini) is the brightest point of light in
the sky. It blazes white in the east in early evening, high in the
south by 10 p.m., and in the west during early-morning hours.
SATURN (magnitude -0.1, in Taurus) shines high in the east far to
Jupiter’s upper right during early evening. Later in the evening it’s
in the south directly to Jupiter’s right. The star Aldebaran sparkles
just 4 degrees (two or three finger-widths at arm’s length) from
Saturn — below it in early evening, and to its lower left or left
later at night. Compare their colors. Saturn is pale yellow; Aldebaran
is more orange.
URANUS and NEPTUNE are hidden in the glare of the Sun.
PLUTO (magnitude 14, in Ophiuchus) is in the southeast before dawn.
(All descriptions that relate to the horizon or zenith — including
the words up, down, right, and left — are written for the world’s
midnorthern latitudes. Descriptions that also depend on longitude are
for North America. Eastern Standard Time, EST, equals Universal Time
[GMT] minus 5 hours.)
More celestial events, sky maps, observing projects, and news of the
world’s astronomy research appear each month in SKY & TELESCOPE, the
essential magazine of astronomy. See our Web site and astronomy
bookstore at http://SkyandTelescope.com/ . Clear skies!
SKY & TELESCOPE, 49 Bay State Rd., Cambridge, MA 02138 *
617-864-7360
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and Sky at a Glance stargazing calendar are provided as a service to
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