Earth Weather / Space Weather

A New Earth?

By: Susie77, 9:25 PM GMT on September 29, 2010

NASA AND NSF-FUNDED RESEARCH FINDS FIRST POTENTIALLY HABITABLE EXOPLANET

WASHINGTON -- A team of planet hunters from the University of
California (UC) Santa Cruz, and the Carnegie Institution of
Washington has announced the discovery of a planet with three times
the mass of Earth orbiting a nearby star at a distance that places it
squarely in the middle of the star's "habitable zone."

This discovery was the result of more than a decade of observations
using the W. M. Keck Observatory in Hawaii, one of the world's
largest optical telescopes. The research, sponsored by NASA and the
National Science Foundation, placed the planet in an area where
liquid water could exist on the planet's surface. If confirmed, this
would be the most Earth-like exoplanet yet discovered and the first
strong case for a potentially habitable one.

To astronomers, a "potentially habitable" planet is one that could
sustain life, not necessarily one where humans would thrive.
Habitability depends on many factors, but having liquid water and an
atmosphere are among the most important.

The new findings are based on 11 years of observations of the nearby
red dwarf star Gliese 581using the HIRES spectrometer on the Keck I
Telescope. The spectrometer allows precise measurements of a star's
radial velocity (its motion along the line of sight from Earth),
which can reveal the presence of planets. The gravitational tug of an
orbiting planet causes periodic changes in the radial velocity of the
host star. Multiple planets induce complex wobbles in the star's
motion, and astronomers use sophisticated analyses to detect planets
and determine their orbits and masses.

"Keck's long-term observations of the wobble of nearby stars enabled
the detection of this multi-planetary system," said Mario R. Perez,
Keck program scientist at NASA Headquarters in Washington. "Keck is
once again proving itself an amazing tool for scientific research."
Steven Vogt, professor of astronomy and astrophysics at UC Santa Cruz,
and Paul Butler of the Carnegie Institution lead the Lick-Carnegie
Exoplanet Survey. The team's new findings are reported in a paper
published in the Astrophysical Journal and posted online at:



http://arxiv.org


"Our findings offer a very compelling case for a potentially habitable
planet," said Vogt. "The fact that we were able to detect this planet
so quickly and so nearby tells us that planets like this must be
really common."

The paper reports the discovery of two new planets around Gliese 581.
This brings the total number of known planets around this star to
six, the most yet discovered in a planetary system outside of our
own. Like our solar system, the planets around Gliese 581 have
nearly-circular orbits.

The new planet designated Gliese 581g has a mass three to four times
that of Earth and orbits its star in just under 37 days. Its mass
indicates that it is probably a rocky planet with a definite surface
and enough gravity to hold on to an atmosphere.
Gliese 581, located 20 light years away from Earth in the
constellation Libra, has two previously detected planets that lie at
the edges of the habitable zone, one on the hot side (planet c) and
one on the cold side (planet d). While some astronomers still think
planet d may be habitable if it has a thick atmosphere with a strong
greenhouse effect to warm it up, others are skeptical. The
newly-discovered planet g, however, lies right in the middle of the
habitable zone.

The planet is tidally locked to the star, meaning that one side is
always facing the star and basking in perpetual daylight, while the
side facing away from the star is in perpetual darkness. One effect
of this is to stabilize the planet's surface climates, according to
Vogt. The most habitable zone on the planet's surface would be the
line between shadow and light (known as the "terminator").

For more information, visit:



http://www.ucsc.edu/news_events




http://carnegiescience.edu




http://www.nasa.gov/topics/universe/features/gliese_581_feature.html

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Super Harvest Moon

By: Susie77, 2:38 PM GMT on September 22, 2010

From NASA


Watch out for the Super Harvest Moon


Sept. 22, 2010: For the first time in almost 20 years, northern autumn is beginning on the night of a full Moon. The coincidence sets the stage for a "Super Harvest Moon" and a must-see sky show to mark the change of seasons.

The action begins at sunset on Sept 22nd, the last day of northern summer. As the sun sinks in the west, bringing the season to a close, the full Harvest Moon will rise in the east, heralding the start of fall. The two sources of light will mix together to create a kind of 360-degree, summer-autumn twilight glow that is only seen on rare occasions.


Keep an eye on the Moon as it creeps above the eastern skyline. The golden orb may appear strangely inflated. This is the Moon illusion at work. For reasons not fully understood by astronomers or psychologists, a low-hanging Moon appears much wider than it really is. A Harvest Moon inflated by the moon illusion is simply gorgeous.


Northern summer changes to fall on Sept. 22nd at 11:09 pm EDT. At that precise moment, called the autumnal equinox, the Harvest Moon can be found soaring high overhead with the planet Jupiter right beside it. The two brightest objects in the night sky will be in spectacular conjunction to mark the change in seasons.

The Harvest Moon gets its name from agriculture. In the days before electric lights, farmers depended on bright moonlight to extend the workday beyond sunset. It was the only way they could gather their ripening crops in time for market. The full Moon closest to the autumnal equinox became "the Harvest Moon," and it was always a welcome sight.

This one would be extra welcome because it is extra "Harvesty."

Usually, the Harvest Moon arrives a few days to weeks before or after the beginning of fall. It's close, but not a perfect match. The Harvest Moon of 2010, however, reaches maximum illumination a mere six hours after the equinox. This has led some astronomers to call it the "Harvestest Moon" or a "Super Harvest Moon." There hasn't been a comparable coincidence since Sept 23, 1991, when the difference was about 10 hours, and it won't happen again until the year 2029.

A Super Harvest Moon, a rare twilight glow, a midnight conjunction—rarely does autumn begin with such celestial fanfare.

Enjoy the show!

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Jupiter

By: Susie77, 8:37 PM GMT on September 20, 2010

CLOSE ENCOUNTER WITH JUPITER: Tonight, Earth and Jupiter converge for their closest encounter until 2022. The giant planet will soar overhead at midnight, outshining everything except the Moon itself. At this time, even a small telescope pointed at Jupiter will reveal the planet's moons, cloud belts and swirling storms. Take a look!

If Jupiter is up at midnight, it must be opposite the sun. Indeed, astronomers call this "Jupiter's night of opposition." The effect of opposition may be seen in the shadow of Jupiter's moon Io, shown here in a photo taken last night by Anthony Wesley of Australia:



"Io was almost on top of its own shadow," points out Wesley. "This is due to the near-perfect alignment of Jupiter, Earth and the sun."

In a coincidence of interplanetary proportions, Uranus is also at opposition tonight. This rare double opposition of two giant planets is a once-in-a-lifetime event. Unlike Jupiter, Uranus is barely visible to the naked eye, a result of its smaller size and greater distance. It looks great, however, through a small telescope. Just point your optics at Jupiter and you will find emerald Uranus about 1o away.

(Courtesy Spaceweather.com)

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Weather Report

By: Susie77, 3:44 PM GMT on September 19, 2010

Rick got me a weather station for my birthday. Who knew they came with a sense of humor?

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Northern Lights out!

By: Susie77, 1:26 AM GMT on September 18, 2010

Skies are clearing in Sweden. The Lights are out!

aurora cam

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A Girly Galaxy

By: Susie77, 4:33 PM GMT on September 09, 2010

From Space.com's Science News

Spiral Galaxy Like Our Own Shines With Pink Clouds
By Denise Chow
SPACE.com Staff Writer
posted: 08 September 2010
07:32 am ET



The wispy arms of a spiral galaxy similar to our own Milky Way can be seen in striking detail in a new image from the European Southern Observatory.

NGC 300, located in the Sculptor Group of galaxies about 6 million light-years from Earth, was photographed by the Wide Field Imager (WFI) at ESO's La Silla Observatory in Chile.

The many energetic star-forming regions along NGC 300's spiral arms are visible in the picture as red and pink clouds.

The image, which was taken with a 50-hour exposure, gives a clear view of NGC 300's structure and shows the apparent size of the galaxy, which is about two-thirds the size of the full moon against the sky.

NGC 300 was discovered by Scottish astronomer James Dunlop, who spotted the bright galaxy from Australia in the early 19th century. As a relatively nearby galaxy that is quite prominent in the southern skies, NGC 300 actually can be seen with regular binoculars.

The galaxy is located in the constellation Sculptor, which contains a few bright stars but is made up of a collection of galaxies that form the Sculptor Group. Other known galaxies that belong to this group include NGC 55, NGC 253 and NGC 7793.

The new image was assembled from a series of separate images that were taken through different filters with a total exposure time of close to 50 hours. The resulting data were collected over the course of many nights of observation that spanned several years.

The extensive observational campaign was part of a larger effort to assemble a census of the stars in the galaxy. Astronomers wanted to count the number and varieties of the stars while singling out regions or individual stars for more focused examination.

In a recent discovery by ESO astronomers, one of the most massive black holes was found in the galaxy, and it was determined that NGC 300 and another galaxy, NGC 55, are slowly spinning around and toward each other, in the early stages of an eventual galactic merger.

By studying the structure and content of NGC 300, astronomers can get a better idea of other characteristics of spiral galaxies like our own Milky Way.

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Too Close for Comfort

By: Susie77, 8:41 PM GMT on September 07, 2010

Yikes:

WASHINGTON -- Two asteroids will pass within the moon's distance from
Earth on Wednesday, Sept. 8. NASA scientists will be available for
satellite interviews Tuesday, Sept. 7, and Wednesday morning to
discuss these near- Earth objects.

The Catalina Sky Survey near Tucson, Ariz., discovered both objects on
Sunday, Sept. 5. The Minor Planet Center in Cambridge, Mass.,
reviewed the observations and determined the preliminary orbits. The
center's personnel concluded both objects would pass within the
distance of the moon to Earth, approximately 240,000 miles. The
asteroids should be visible with moderate-sized amateur telescopes.

Neither asteroid will hit Earth. Asteroid 2010 RX30 is estimated to be
approximately 32 to 65 feet in size and will pass within
approximately 154,000 miles of Earth at 5:51 a.m. EDT Wednesday. The
second object, 2010 RF12, estimated to be 20 to 46 feet in size, will
pass within approximately 49,000 miles at 5:12 p.m. EDT.

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Northern Lights visible NOW! (2325 UTC)

By: Susie77, 11:28 PM GMT on September 05, 2010

Aurora web cam

Screenshot taken 2327 UTC:

0012 UTC 1712 CDT:



Updated: 12:13 AM GMT on September 06, 2010

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Late Summer Night Skies

By: Susie77, 1:24 AM GMT on September 05, 2010

I don't like promoting anything that comes from Fox News, but this was too good not to share (and, for a refreshing change from Fox, also both truthy and nonpolitical). Enjoy!

Late Summer Sky Viewing

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Taste of Fall

By: Susie77, 9:47 PM GMT on September 03, 2010

What a beautiful day here in St. Louis. Low temps and humidity, lovely cool breeze from the North, crystal blue skies.... love it! I'm also thankful that the same front that brings us this happiness is steering Earl away from the folks on the Right Coast.

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About Susie77

Sometimes I complain about the earthly weather, but mostly I like to post about astronomy and space events. Hope you enjoy the articles.

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