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, August 26, 2008
Sky survey yields new cosmic haul
Astronomers looking through the data from the Sloan Digital Sky Survey, the world's largest survey of galaxies, have found a new haul of objects closer to home - including one with a potentially exotic origin.
By searching through a survey region known as Stripe 82, a team led by Dr Andrew Becker of the University of Washington, has discovered almost 50 new asteroid-sized bodies in the outer regions of our Solar System.
As part of a search for supernovae - exploding stars in distant galaxies - the robotic Sloan telescope in New Mexico revisited this area of the southern sky every three days.
By comparing images taken on different nights, the Washington team was able to detect the asteroids as they moved across the sky. It's probably a mixture of ice and rock, rather like a comet Dr Andrew Becker, University of Washington
As team member Dr Lynne Jones pointed out: "If you can find things that explode, you can also find things that move, but you need different tools to look for them."
While most of the newly discovered objects are normal members of the Kuiper belt, a large band of icy bodies stretching beyond the orbit of Neptune, there were also surprises.
The team discovered two Neptunian Trojans, asteroids which share the same orbit as the outermost giant planet.
"Jupiter has plenty of trojans," Dr Becker told me, "and we knew that Neptune must have a similar population of objects. Surprisingly, not many had been found before this survey."
The team's prize find is an object given the temporary designation of 2006 SQ372. This icy body is currently roughly two billion miles away, just closer to the Sun than Neptune, but is beginning a journey that will take it out to a distance of 150 billion miles from the Earth.
Solar System's newest member points to inner Oort Cloud
An ice-rock minor planet 30 to 60 miles in diameter, discovered two years ago between the orbits of Uranus and Neptune (each being a mean distance of 2.72 and 4.35 billion kilometres from Earth respectively) could be a member of the ‘inner Oort Cloud’. But this is only part of the story as the object, dubbed 2006 SQ372, is currently at perihelion (the point where it’s closest to the Sun) on a highly elliptical orbit that will see it sail right out to nearly 1,600 astronomical units (an astronomical unit, or AU, being the distance between the Earth and Sun — 149,598,000 kilometres). That is 40 times the distance out to Pluto, or 239 billion kilometres. It will return in 22,500 years.
2006 SQ372, first discovered by a team from the University of Washington using Sloan Digital Sky Survey data (SDSS), is comparable to Sedna — another minor planet that has a highly elliptical orbit. Sedna’s eccentricity is 0.855 and its perihelion and aphelion positions are 76 and 975 AU respectively. The orbit of 2006 SQ372 has an eccentricity of 0.976 and its perihelion and aphelion distances are 24 and 2,010 AU. The ellipse of 2006 SQ372 is four times longer than it is wide and crosses the orbits of Pluto and Neptune. For comparison, Earth’s orbital eccentricity is 0.0167 and its perihelion and aphelion distances 0.983 and 1.017 AU respectively.
More Story...at http://astronomynow.com/080818NewObjectPointsToInnerOortCloud.html
Laboratory tests aboard NASA's Phoenix Mars Lander have identified water in a soil sample. The lander's robotic arm delivered the sample Wednesday to an instrument that identifies vapors produced by the heating of samples. scoop."We have water," said William Boynton of the University of Arizona, lead scientist for the Thermal and Evolved-Gas Analyzer, or TEGA. "We've seen evidence for this water ice before in observations by the Mars Odyssey orbiter and in disappearing chunks observed by Phoenix last month, but this is the first time Martian water has been touched and tasted."
With enticing results so far and the spacecraft in good shape, NASA also announced operational funding for the mission will extend through Sept. 30. The original prime mission of three months ends in late August. The mission extension adds five weeks to the 90 days of the prime mission.
"Phoenix is healthy and the projections for solar power look good, so we want to take full advantage of having this resource in one of the most interesting locations on Mars," said Michael Meyer, chief scientist for the Mars Exploration Program at NASA Headquarters in Washington.
The soil sample came from a trench approximately 2 inches deep. When the robotic arm first reached that depth, it hit a hard layer of frozen soil. Two attempts to deliver samples of icy soil on days when fresh material was exposed were foiled when the samples became stuck inside the scoop. Most of the material in Wednesday's sample had been exposed to the air for two days, letting some of the water in the sample vaporize away and making the soil easier to handle.
"Mars is giving us some surprises," said Phoenix principal investigator Peter Smith of the University of Arizona. "We're excited because surprises are where discoveries come from. One surprise is how the soil is behaving. The ice-rich layers stick to the scoop when poised in the sun above the deck, different from what we expected from all the Mars simulation testing we've done. That has presented challenges for delivering samples, but we're finding ways to work with it and we're gathering lots of information to help us understand this soil."
Since landing on May 25, Phoenix has been studying soil with a chemistry lab, TEGA, a microscope, a conductivity probe and cameras. Besides confirming the 2002 finding from orbit of water ice near the surface and deciphering the newly observed stickiness, the science team is trying to determine whether the water ice ever thaws enough to be available for biology and if carbon-containing chemicals and other raw materials for life are present.
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