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, August 28, 2009
Newfound Planet Might Be Near Death
This artist's impression depicts an exoplanet similar to the newly discovered WASP-18b. As seen from the planet, the host star spans an angle of more than 30 degree and hovers menacingly at a fixed position in the sky.
A newly discovered planet that whips around its star in less than a day may have been found mere cosmic moments before its demise.
The planet, WASP-18b, is one of the "hot Jupiter" class of planets that are huge in size (10 times the mass of Jupiter in this case), but orbit very close to their stars. Their very existence was surprising to astronomers when the first of them were found a few years back. Now they've become common discoveries.
But this scorched, gaseous world is only one of two known exoplanets that orbits its star in less than one Earth day (0.94 days to be exact). Coupled with its hefty mass, this leads to strong gravitational tugs between the planet and its star, WASP-18. (WASP stands for the Wide Angle Search for Planets, run by several universities in Britain.)
Full story... Image credit: C. CARREAU/ESA/Nature News source: livescience.com
On August 16th, Philippine astrophotographer Christopher Go used a modern 11-inch Celestron telescope to photograph Io casting its shadow on Ganymede. "I captured this rare event through a hole in the clouds," says Go. "It was a lucky clearing!"
In the movie, Io and Ganymede reveal themselves as fully-formed worlds with surface markings and a spherical shape. Io's circular shadow cuts a dark swath across Ganymede, transforming that giant moon (it is larger than Mercury) into a succession of crescents rarely seen by observers. Indeed, as far as we know, no telescope on Earth or space has ever photographed one of Jupiter's moons casting its circular shadow so clearly across another.
NASA Researchers Make First Discovery of Life's Building Block in Comet
NASA scientists have discovered glycine, a fundamental building block of life, in samples of comet Wild 2 returned by NASA's Stardust spacecraft.
"Glycine is an amino acid used by living organisms to make proteins, and this is the first time an amino acid has been found in a comet," said Dr. Jamie Elsila of NASA's Goddard Space Flight Center in Greenbelt, Md. "Our discovery supports the theory that some of life's ingredients formed in space and were delivered to Earth long ago by meteorite and comet impacts."
Elsila is the lead author of a paper on this research accepted for publication in the journal Meteoritics and Planetary Science. The research will be presented during the meeting of the American Chemical Society at the Marriott Metro Center in Washington, DC, August 16.
Astronomers have discovered the first planet that orbits in the opposite direction to the spin of its star.Planets form out of the same swirling gas cloud that creates a star, so they are expected to orbit in the same direction that the star rotates. The new planet is thought to have been flung into its "retrograde" orbit by a close encounter with either another planet or with a passing star.
The new object has been named WASP-17b. It is the 17th exoplanet to have been discovered by the Wide Area Search for Planets (WASP) consortium of UK universities. The gas giant is about twice the size of Jupiter, but has about half the mass. This bloatedness might also be rooted in the close encounter that changed the planet's direction. WASP-17b was detected using an array of cameras set up to monitor hundreds of thousands of stars.
The work has been submitted to the Astrophysical Journal for publication.
Scientists spot massive methane rainstorm over Titan
In this 2007 file photo, bright mid-latitude clouds near the bottom of this view hint at the ongoing cycling of methane on Titan.
Astronomers have discovered a storm system on Titan the size of India. It popped up in April 2008 in the moon's tropics, a latitude belt not known for cloudiness. The storm, reported in the latest edition of the journal Nature, is another "a-ha" moment as scientists try to figure out how Titan's bizarre atmosphere works and the forces responsible for sculpting the moon's surface.The events suggested an atmosphere whose storm systems can significantly disturb Titan's equivalent of Earth's jet streams, triggering cloudiness elsewhere. It also helps explain why the surface in the tropics appears heavily sculpted by liquids despite the general dearth of clouds, the team suggests.
The European Space Agency's Huygens probe in 2004 returned pictures of what looked liked stream beds and other features seemingly carved by liquid on Titan's surface. Their structures implied they had formed under heavy downpours, much like what one sees in the US's desert Southwest. Indeed, the longer researchers stare at Titan, the more Earth-like its processes appear – processes playing out right before their telescopes' and spacecraft's sensors.
This artist's concept shows a celestial body about the size of our moon slamming at great speed into a body the size of Mercury. NASA's Spitzer Space Telescope found evidence that a high-speed collision of this sort occurred a few thousand years ago around a young star, called HD 172555, still in the early stages of planet formation. The star is about 100 light-years from Earth.
Spitzer detected the signatures of vaporized and melted rock, in addition to rubble, all flung out from the giant impact. Further evidence from the infrared telescope shows that these two bodies must have been traveling at a velocity relative to each other of at least 10 kilometers per second (about 22,400 miles per hour).
As the bodies slammed into each other, a huge flash of light would have been emitted. Rocky surfaces were vaporized and melted, and hot matter was sprayed everywhere. Spitzer detected the vaporized rock in the form of silicon monoxide gas, and the melted rock as a glassy substance called obsidian. On Earth, obsidian can be found around volcanoes, and in black rocks called tektites often found around meteor craters.
Shock waves from the collision would have traveled through the planet, throwing rocky rubble into space. Spitzer also detected the signatures of this rubble.
In the end, the larger planet is left skinned, stripped of its outer layers. The core of the smaller body and most of its surface were absorbed by the larger one. This merging of rocky bodies is how planets like Earth are thought to form.
Astronomers say a similar type of event stripped Mercury of its crust early on in the formation of our solar system, flinging the removed material away from Mercury, out into space and into the sun. Our moon was also formed by this type of high-speed impact: a body the size of Mars is thought to have slammed into a young Earth about 30 to 100 million years after the sun formed. The sun is now 4.5 billion years old. According to this theory, the resulting molten rock, vapor and shattered debris mixed with debris from Earth to form a ring around our planet. Over time, this debris coalesced to make the moon.
Meteorite Found on Mars Yields Clues About Planet's Past
This view of a rock called "Block Island," the largest meteorite yet found on Mars, comes from the panoramic camera (Pancam) on NASA's Mars Exploration Rover Opportunity.
NASA's Mars Rover Opportunity is investigating a metallic meteorite the size of a large watermelon that is providing researchers more details about the Red Planet's environmental history.
The rock, dubbed "Block Island," is larger than any other known meteorite on Mars. Scientists calculate it is too massive to have hit the ground without disintegrating unless Mars had a much thicker atmosphere than it has now when the rock fell. An atmosphere slows the descent of meteorites. Additional studies also may provide clues about how weathering has affected the rock since it fell.
Two weeks ago, Opportunity had driven approximately 180 meters (600 feet) past the rock in a Mars region called Meridiani Planum. An image the rover had taken a few days earlier and stored was then transmitted back to Earth. The image showed the rock is approximately 60 centimeters (2 feet) in length, half that in height, and has a bluish tint that distinguishes it from other rocks in the area. The rover team decided to have Opportunity backtrack for a closer look, eventually touching Block Island with its robotic arm.
NASA's Kepler Mission Spies Changing Phases in a Distant World
NASA's new exoplanet-hunting Kepler space telescope has detected the atmosphere of a known giant gas planet, demonstrating the telescope's extraordinary scientific capabilities. The discovery will be published Friday in the journal Science.
The find is based on a relatively short 10 days of test data collected before the official start of science operations. Kepler was launched March 6, 2009, from Cape Canaveral Air Force Station in Florida. The observation demonstrates the extremely high precision of the measurements made by the telescope, even before its calibration and data analysis software were finished.
"As NASA's first exoplanets mission, Kepler has made a dramatic entrance on the planet-hunting scene," said Jon Morse, director of the Science Mission Directorate's Astrophysics Division at NASA Headquarters in Washington. "Detecting this planet's atmosphere in just the first 10 days of data is only a taste of things to come. The planet hunt is on!"
Kepler team members say these new data indicate the mission is indeed capable of finding Earth-like planets, if they exist. Kepler will spend the next three-and-a-half years searching for planets as small as Earth, including those that orbit stars in a warm zone where there could be water. It will do this by looking for periodic dips in the brightness of stars, which occur when orbiting planets transit, or cross in front of, the stars.
"When the light curves from tens of thousands of stars were shown to the Kepler science team, everyone was awed; no one had ever seen such exquisitely detailed measurements of the light variations of so many different types of stars," said William Borucki, the principal science investigator and lead author of the paper.
The observations were collected from a planet called HAT-P-7, known to transit a star located about 1,000 light years from Earth. The planet orbits the star in just 2.2 days and is 26 times closer than Earth is to the sun. Its orbit, combined with a mass somewhat larger than the planet Jupiter, classifies this planet as a "hot Jupiter." It is so close to its star, the planet is as hot as the glowing red heating element on a stove.
The Kepler measurements show the transit from the previously detected HAT-P-7. However, these new measurements are so precise, they also show a smooth rise and fall of the light between transits caused by the changing phases of the planet, similar to those of our moon. This is a combination of both the light emitted from the planet and the light reflected off the planet. The smooth rise and fall of light is also punctuated by a small drop in light, called an occultation, exactly halfway between each transit. An occultation happens when a planet passes behind a star.
The new Kepler data can be used to study this hot Jupiter in unprecedented detail. The depth of the occultation and the shape and amplitude of the light curve show the planet has an atmosphere with a day-side temperature of about 4,310 degrees Fahrenheit. Little of this heat is carried to the cool night side. The occultation time compared to the main transit time shows the planet has a circular orbit. The discovery of light from this planet confirms the predictions by researchers and theoretical models that the emission would be detectable by Kepler.
This new discovery also demonstrates Kepler has the precision to find Earth-size planets. The observed brightness variation is just one and a half times what is expected for a transit caused by an Earth-sized planet. Although this is already the highest precision ever obtained for an observation of this star, Kepler will be even more precise after analysis software being developed for the mission is completed. "This early result shows the Kepler detection system is performing right on the mark," said David Koch, deputy principal investigator of NASA's Ames Research Center at Moffett Field, Calif. "It bodes well for Kepler's prospects to be able to detect Earth-size planets."
Kepler is a NASA Discovery mission. Ames is responsible for the ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Kepler mission development. Ball Aerospace and Technologies Corp. of Boulder, Colo., is responsible for developing the Kepler flight system and supporting mission operations.
Methane on Mars is produced and destroyed far faster than on Earth, according to analysis of recent data.Scientists in Paris used a computer climate model for the Red Planet to simulate observations made from Earth.It shows the gas is unevenly distributed in the Martian atmosphere and changes with the seasons.The presence of methane on Mars is intriguing because its origin could either be life or geological activity - including volcanism. The results the French team used were published in January this year in the journal Science. They were gathered by an American team using a technique called infrared spectroscopy at three different ground-based telescopes to monitor about 90% of the planet's surface.
In 2003 "plumes" of methane were identified. At one point, the primary plume of methane contained an estimated 19,000 tonnes of the gas.Dr Michael Mumma, director of Nasa's Goddard Center for Astrobiology and lead author on the previous paper, told BBC News it was vital to understand how methane was destroyed on Mars and to explain how so much of the gas is produced and destroyed so quickly on the Red Planet.Dr Mumma does not rule out a biological explanation for the phenomenon but says it is possible that geology alone could be responsible.
This artist's impression shows the supergiant star Betelgeuse as it was revealed thanks to different state-of-the-art techniques on ESO's Very Large Telescope, which allowed two independent teams of astronomers to obtain the sharpest ever views of the supergiant star Betelgeuse. They show that the star has a vast plume of gas almost as large as our Solar System and a gigantic bubble boiling on its surface. These discoveries provide important clues to help explain how these mammoths shed material at such a tremendous rate. The scale in units of the radius of Betelgeuse as well as a comparison with the Solar System is also provided. Image: ESO
This collage shows the Orion constellation in the sky (Betelgeuse is identified by the marker), a zoom towards Betelgeuse, and the sharpest ever image of this supergiant star, which was obtained with NACO on ESO's Very Large Telescope. Image: ESO
This image of "Block Island" was taken on July 28, 2009, with the front hazard-identification camera on NASA’s Mars Exploration Rover Opportunity.
The Opportunity rover has eyed an odd-shaped, dark rock, about 0.6 meters (2 feet) across on the surface of Mars, which may be a meteorite. The team spotted the rock called "Block Island," on July 18, 2009, in the opposite direction from which it was driving. The rover then backtracked some 250 meters (820 feet) to study it closer. Scientists will be testing the rock with the alpha particle X-ray spectrometer to get composition measurements and to confirm if indeed it is a meteorite.
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