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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Tuesday, December 19, 2006
Spitzer Telescope Reveals Objects in Early Universe
New observations from NASA's Spitzer Space Telescope strongly suggest that infrared light detected in a prior study originated from clumps of the very first objects of the universe. The recent data indicate this patchy light is splattered across the entire sky and comes from clusters of bright, monstrous objects more than 13 billion light-years away. Astronomers believe the objects are either the first stars - humongous stars more than 1,000 times the mass of our sun - or voracious black holes that are consuming gas and spilling out tons of energy. If the objects are stars, then the observed clusters might be the first mini-galaxies containing a mass of less than about one million suns. The Milky Way galaxy holds the equivalent of approximately 100 billion suns and was probably created when mini-galaxies like these merged.
Cassini spacecraft has found 1-mile-high mountain on Saturn's giant moon, Titan. The image was acquired during the probe flyby on the shrouded moon on October 25. The mountain stretches for nearly 100 miles long. It is the tallest ever seen on Titan and and probably formed from the same process that occurs in the Earth's mid-ocean ridge. A combination of infra-red and radar data was used to analyze the image.
The small open star cluster Pismis 24 lies in the core of the large emission nebula NGC 6357 in Sagittarius, about 8,000 light-years away from Earth. Some of the stars in this cluster are extremely massive and emit intense ultraviolet radiation. The brightest object in the picture is designated Pismis 24-1. It was once thought to weigh as much as 200 to 300 solar masses. This would not only have made it by far the most massive known star in the galaxy, but would have put it considerably above the currently believed upper mass limit of about 150 solar masses for individual stars. However, high-resolution Hubble Space Telescope images of the star show that it is really two stars orbiting one another (inset pictures at top right and bottom right). They are estimated to each be 100 solar masses. The Hubble Advanced Camera for Surveys images were taken in April 2006.
This is a big news! NASA announced today that they got images that have shown a strong sign that water is currently at present on Mars. One image revealed a crater site where two gullies flowed. The gullies suggest water carried sediment through them sometime during the past seven years. The shape of the deposits strongly indicate water involved in the process. The new finding boost the expectation that microbial life could exist on Mars! I am glad I am still alive to look at this great discovery. The images were photographed by NASA's orbiter, Mars Global Survery which is now missing. The two sites are located in the Terra Sirenum and the Centauri Montes regions of southern Mars.
Read NASA News Release (as I received it via email):
NASA photographs have revealed bright new deposits seen in two gullies on Mars that suggest water carried sediment through them sometime during the past seven years. "These observations give the strongest evidence to date that water still flows occasionally on the surface of Mars," said Dr. Michael Meyer, lead scientist for NASA's Mars Exploration Program, Washington.
Liquid water, as opposed to the water ice and water vapor known to exist at Mars, is considered necessary for life. The new findings heighten intrigue about the potential for microbial life on Mars. The Mars Orbiter Camera on NASA's Mars Global Surveyor provided the new evidence. The deposits appear in images it took in 2004 and 2005 but not in a 1999 image of one site or a 2001 image of the other site."The shapes of these deposits are what you would expect to see if the material were carried by flowing water," said Dr. Michael Malin of Malin Space Science Systems, San Diego . "They have finger-like branches at the downhill end and are easily diverted around small obstacles." Malin is principal investigator for the camera and lead author of a report about the findings published in the journal Science.
The atmosphere of Mars is so thin and the temperature so cold that liquid water cannot persist at the surface. It would rapidly evaporate or freeze. Researchers propose that water could remain liquid long enough, after breaking out from an underground source, to carry debris downslope before totally freezing. The two fresh deposits are each several hundred meters, or yards, long. The light tone of the deposits could be from surface frost continuously replenished by ice within the body of the deposit. Another possibility is a salty crust, which would be a sign of water's effects in concentrating the salts. If the deposits had resulted from dry dust slipping down the slope, they would likely be dark, based on the dark tones of dust freshly disturbed by rover tracks, dust devils and fresh craters on Mars.
Mars Global Surveyor has discovered tens of thousands of gullies on slopes inside craters and other depressions on Mars. Most gullies are at latitudes of 30 degrees or higher. Malin and his team first reported the discovery of the gullies in 2000. To look for changes that might indicate present-day flow of water, his camera team repeatedly imaged hundreds of the sites. One pair of images showed a gully that appeared after mid-2002. That site was on a sand dune, and the gully-cutting process was interpreted as a dry flow of sand.
Today's announcement is the first to reveal newly deposited material apparently carried by fluids after earlier imaging of the same gullies. The two sites are inside craters in the Terra Sirenum and the Centauri Montes regions of southern Mars."These fresh deposits suggest that at some places and times on present-day Mars, liquid water is emerging from beneath the ground and briefly flowing down the slopes. This possibility raises questions about how the water would stay melted below ground, how widespread it might be, and whether there's a below-ground wet habitat conducive to life. Future missions may provide the answers," said Malin.
Besides looking for changes in gullies, the orbiter's camera team assessed the rate at which new impact craters appear. The camera photographed approximately 98 percent of Mars in 1999 and approximately 30 percent of the planet was photographed again in 2006. The newer images show 20 fresh impact craters, ranging in diameter from 2 meters (7 feet) to 148 meters (486 feet) that were not present approximately seven years earlier. These results have important implications for determining the ages of features on the surface of Mars. These results also approximately match predictions and imply that Martian terrain with few craters is truly young.
Mars Global Surveyor began orbiting Mars in 1997. The spacecraft is responsible for many important discoveries. NASA has not heard from the spacecraft since early November. Attempts to contact it continue. Its unprecedented longevity has allowed monitoring Mars for over several years past its projected lifetime.
Astronomers witnessed a rare event when a monster black hole consumed a star. The complete process of the event from its first bite to final swallowing stage was successfully observed. Using the NASA's space-based-telescope, Galaxy Evolution Explorer, astronomers saw a bright ultraviolet flare when the star plunged into the giant black hole. The galaxy that host the black hole is located 4 billion light years away in the constellation Bootes.
MRO Snapped Pictures of Spirit Rover, Viking 1 and 2 Landing Sites!
The new HiRISE images from Mars Reconaissance Orbiter (MRO) have been released. One of the image shows the durable Mars Rover Spirit and the area that it investigated, the landing site and the visible tracks of the rover. Click this link to see more detail of the marked areas as shown above.
The new released images also feature the landing site of Viking 1 and Viking 2 Follow this link to see the pictures of each area investigated by Viking 1 and Viking 2:
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