02 - Full Moon
at 19:14 UT
05 - Taurid
(south) meteor shower peaks. Active
between 25 Sept and 25 Nov.
Associated with Comet 2P/Encke.
09 - Moon near
Mars (morning sky) at 14h UT. Mag. +0.3.
12 -Taurid (north) meteor
shower peaks. May produce the occasional
17 -Leonid meteor shower
peaks at 9h UT. Arises from debris ejected
Comet Tempel-Tuttle in 1533. Expect about 25
to 30 meteors per hour under
dark skies. Predictions of enhanced activity
between 21-22h UT on 17 Nov
(favours sky watchers in Asia).
21 -Alpha Monocerotid meteor
shower peaks at 15:25 UT. A usually minor
shower active 15-25 Nov. Radiant is near Procyon.
Predictions of enhanced
activity this year. Timing favours Far East
Asia, Australia and across the
Pacific to Alaska.
00 0 0
0 0 0//
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Friday, September 25, 2009
NASA Spacecraft Sees Ice on Mars Exposed by Meteor Impacts
NASA's Mars Reconnaissance Orbiter has revealed frozen water hiding just below the surface of mid-latitude Mars. The spacecraft's observations were obtained from orbit after meteorites excavated fresh craters on the Red Planet.
Scientists controlling instruments on the orbiter found bright ice exposed at five Martian sites with new craters that range in depth from approximately half a meter to 2.5 meters (1.5 feet to 8 feet). The craters did not exist in earlier images of the same sites. Some of the craters show a thin layer of bright ice atop darker underlying material. The bright patches darkened in the weeks following initial observations, as the freshly exposed ice vaporized into the thin Martian atmosphere. One of the new craters had a bright patch of material large enough for one of the orbiter's instruments to confirm it is water-ice.
The finds indicate water-ice occurs beneath Mars' surface halfway between the north pole and the equator, a lower latitude than expected in the Martian climate.
This Mini-RF image from NASA's powerful Lunar Reconnaissance Orbiter shows radar imagery of the lunar south pole, a potential reservoir for hidden water ice, in new images released Sept. 17, 2009.
Since man first touched the moon and brought pieces of it back to Earth, scientists have thought that the lunar surface was bone dry. But new observations from three different spacecraft have put this notion to rest with what has been called "unambiguous evidence" of water across the surface of the moon.
The new findings, detailed in the Sept. 25 issue of the journal Science, come in the wake of further evidence of lunar polar water ice by NASA's Lunar Reconnaissance Orbiter and just weeks before the planned lunar impact of NASA's LCROSS satellite, which will hit one of the permanently shadowed craters at the moon's south pole in hope of churning up evidence of water ice deposits in the debris field.
The moon remains drier than any desert on Earth, but the water is said to exist on the moon in very small quantities. One ton of the top layer of the lunar surface would hold about 32 ounces of water, researchers said.
Full story... Source: Space.com Image credit: NASA/APL/LPI/Space.com
NASA's Spitzer Spots Clump of Swirling Planetary Material
This artist's conception shows a lump of material in a swirling, planet-forming disk.
Astronomers have witnessed odd behavior around a young star. Something, perhaps another star or a planet, appears to be pushing a clump of planet-forming material around. The observations, made with NASA's Spitzer Space Telescope, offer a rare look into the early stages of planet formation.
Planets form out of swirling disks of gas and dust. Spitzer observed infrared light coming from one such disk around a young star, called LRLL 31, over a period of five months. To the astronomers' surprise, the light varied in unexpected ways, and in as little time as one week. Planets take millions of years to form, so it's rare to see anything change on time scales we humans can perceive.
One possible explanation is that a close companion to the star -- either a star or a developing planet -- could be shoving planet-forming material together, causing its thickness to vary as it spins around the star.
Full story... Source: NASA/JPL News Release Image credit: NASA/JPL-Caltech
New photographs of the center of the Milky Way reveal the chaotic environment at the heart of our galaxy, where a supermassive black hole is thought to lurk.
The close-up views come from two recent projects - one undertaken by an amateur astronomer. Stephane Guisard, an engineer at the European Southern Observatory (ESO) in Chile, used his personal 10-cm telescope to take 1,200 individual images over 29 nights during his free time. He then combined the photos, which took a total of more than 200 hours of exposure time, into a stunning mosaic image of the Milky Way's center.
The vista reveals an area of the sky spanning from the constellation Sagittarius to the constellation Scorpius. Running through the image is the dusty track of the Milky Way's disk - the dense Frisbee shape that contains the spiral arms of the galaxy. Colorful nebulae - including the pink cloud of the Lagoon Nebula (also known as Messier 8) - where furious star formation is occurring - dot the scene.
Scientists Complete First Geological Global Map Of Jupiter's Satellite Ganymede
Scientists have assembled the first global geological map of the Solar System's largest moon – and in doing so have gathered new evidence into the formation of the large, icy satellite.
Wes Patterson, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, led a seven-year effort to craft a detailed map of geological features on Ganymede, the largest moon of Jupiter. Patterson and a half-dozen scientists from several institutions compiled the global map – only the third ever completed of a moon, after Earth's moon and Jupiter's cratered satellite Callisto – using images from NASA's historic Voyager and Galileo missions.
First great snapshots from new vision of Hubble space telescope
NASA's Hubble Space Telescope is back in business, ready to uncover new worlds, peer ever deeper into space, and even map the invisible backbone of the universe. The first snapshots from the refurbished Hubble showcase the 19-year-old telescope's new vision. Topping the list of exciting new views are colorful multi-wavelength pictures of far-flung galaxies, a densely packed star cluster, an eerie "pillar of creation," and a "butterfly" nebula. With its new imaging camera, Hubble can view galaxies, star clusters, and other objects across a wide swath of the electromagnetic spectrum, from ultraviolet to near-infrared light. A new spectrograph slices across billions of light-years to map the filamentary structure of the universe and trace the distribution of elements that are fundamental to life. The telescope's new instruments also are more sensitive to light and can observe in ways that are significantly more efficient and require less observing time than previous generations of Hubble instruments. NASA astronauts installed the new instruments during the space shuttle servicing mission in May 2009. Besides adding the instruments, the astronauts also completed a dizzying list of other chores that included performing unprecedented repairs on two other science instruments.
NASA's Cassini spacecraft has found within Saturn's G ring an embedded moonlet that appears as a faint, moving pinprick of light. Scientists believe it is a main source of the G ring and its single ring arc. Cassini imaging scientists analyzing images acquired over the course of about 600 days found the tiny moonlet, half a kilometer (about a third of a mile) across, embedded within a partial ring, or ring arc, previously found by Cassini in Saturn's tenuous G ring.
The finding is being announced today in an International Astronomical Union circular. Images can be found at http://www.nasa.gov/cassini, http://saturn.jpl.nasa.gov and http://ciclops.org.
The shadow of the moon Janus dwarfs the shadow of Daphnis on Saturn's A ring in this image taken as the planet approached its August 2009 equinox.
Daphnis (8 kilometers, or 5 miles across) orbits in the A ring's Keeler Gap and, along with the moon's attending edge waves, can be seen casting a short shadow in the top left quadrant of the image. Equinox has exposed shadows cast by these edge waves, or vertical structures of ring material created by Daphnis' gravity.
Janus (179 kilometers, or 111 miles across) is not pictured here, but the moon's shadow stretches across the A ring from the center of the image to near the Encke Gap on the left of the image. The Cassini Division appears bright on the right of the image.
The novel illumination geometry created around the time of Saturn's August 2009 equinox allows out-of-plane structures and moons orbiting in or near the plane of Saturn's equatorial rings to cast shadows onto the rings. These scenes are possible only during the few months before and after Saturn's equinox, which occurs only once in about 15 Earth years. To learn more about this special time and to see movies of moons' shadows moving across the rings, see Moon Shadow in Motion and Weaving a Shadow.
This view looks toward the unilluminated side of the rings from about 27 degrees above the ringplane.
The image was taken in visible light with the Cassini spacecraft wide-angle camera on July 11, 2009. The view was obtained at a distance of approximately 491,000 kilometers (305,000 miles) from Saturn and at a Sun-Saturn-spacecraft, or phase, angle of 26 degrees. Image scale is 26 kilometers (16 miles) per pixel.
Oort cloud, is a postulated spherical cloud
of comets situated about 50,000 to 100,000 AU from
the Sun. This is approximately 1000 times the distance
from the Sun to Pluto or roughly one light year, almost
a quarter of the distance from the Sun to Proxima
Centauri, the star nearest the Sun. The Oort cloud
would have its inner disk at the ecliptic from the
Kuiper belt. Although no direct observations have
been made of such a cloud, it is believed to be the
source of most or all comets entering the inner solar
system (some short-period comets may come from the
Kuiper belt), based on observations of the orbits
of comets. Source: Wikipedia