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Posts Tagged ‘meteors’

Meteorites Yield Clues To Red Planet’s Early Atmosphere


Geologists who analyzed 40 meteorites that fell to Earth from Mars unlocked secrets of the Martian atmosphere hidden in the chemical signatures of these ancient rocks. Their study, published April 17 in the journal Nature, shows that the atmospheres of Mars and Earth diverged in important ways very early in the 4.6 billion year evolution of our solar system.

Heather Franz, a former University of Maryland research associate who now works on the Curiosity rover science team at the NASA Goddard Space Flight Center, led the study with James Farquhar, co-author and UMD geology professor. The researchers measured the sulfur composition of 40 Mars meteorites—a much larger number than in previous analyses. Of more than 60,000 meteorites found on Earth, only 69 are believed to be pieces of rocks blasted off the Martian surface.

The meteorites are igneous rocks that formed on Mars, were ejected into space when an asteroid or comet slammed into the red planet, and landed on Earth. The oldest meteorite in the study is about 4.1 billion years old, formed when our solar system was in its infancy. The youngest are between 200 million and 500 million years old.

Link To Full Story

Astronomers Celebrate “Celestail Pollution” From Perseid Meteor Shower


Credit: Gemini Observatory/AURA

Credit: Gemini Observatory/AURA

This weekend, as millions of people gaze up at the stars and wait for Perseid meteors to streak across the sky, one would hardly think that these awe-inspiring “shooting stars” are also a source of atmospheric pollution.

However, meteors, like those from this month’s Perseid meteor shower, burn up high in the Earth’s atmosphere leaving behind gases. “It’s a form of natural pollution,” says Gemini Observatory’s Chad Trujillo who heads up the facility’s state-of-the-art Adaptive Optics (AO) program.

“One of the gases left behind by meteors is sodium, which collects in a layer about 60 miles (90 kilometers) above the Earth,” says Trujillo (see animation). “The reason astronomers are so fond of this particular pollution layer is because we can make it glow by using a sodium laser to excite this sodium and produce temporary, artificial stars wherever we like. Believe it or not,” jokes Trujillo, “there aren’t enough stars in the sky for astronomers!”

Full Story: http://www.gemini.edu/node/12050

NASA Probe Observes Meteors Colliding With Saturn’s Rings


Image Credit: NASA/JPL-Caltech/Space Science Institute/Cornell

Image Credit: NASA/JPL-Caltech/Space Science Institute/Cornell

NASA’s Cassini spacecraft has provided the first direct evidence of small meteoroids breaking into streams of rubble and crashing into Saturn’s rings.

These observations make Saturn’s rings the only location besides Earth, the moon and Jupiter where scientists and amateur astronomers have been able to observe impacts as they occur. Studying the impact rate of meteoroids from outside the Saturnian system helps scientists understand how different planet systems in our solar system formed.

The solar system is full of small, speeding objects. These objects frequently pummel planetary bodies. The meteoroids at Saturn are estimated to range from about one-half inch to several yards (1 centimeter to several meters) in size. It took scientists years to distinguish tracks left by nine meteoroids in 2005, 2009 and 2012.

Results from Cassini have already shown Saturn’s rings act as very effective detectors of many kinds of surrounding phenomena, including the interior structure of the planet and the orbits of its moons. For example, a subtle but extensive corrugation that ripples 12,000 miles (19,000 kilometers) across the innermost rings tells of a very large meteoroid impact in 1983.

Full Story: http://www.jpl.nasa.gov/news/news.php?release=2013-147

Quadrantids Will Create Brief, Beautiful Show on Jan. 4

December 23, 2011 Leave a comment

Image Credit: NASA/MSFC/MEO/B. Cooke

The 2012 Quadrantids, a little-known meteor shower named after an extinct constellation, will present an excellent chance for hardy souls to start the year off with some late-night meteor watching.

Peaking in the wee morning hours of Jan. 4, the Quadrantids have a maximum rate of about 100 per hour, varying between 60-200. The waxing gibbous moon will set around 3 a.m. local time, leaving about two hours of excellent meteor observing before dawn. It’s a good thing, too, because unlike the more famous Perseid and Geminid meteor showers, the Quadrantids only last a few hours — it’s the morning of Jan. 4, or nothing.

Like the Geminids, the Quadrantids originate from an asteroid, called 2003 EH1. Dynamical studies suggest that this body could very well be a piece of a comet which broke apart several centuries ago, and that the meteors you will see before dawn on Jan. 4 are the small debris from this fragmentation. After hundreds of years orbiting the sun, they will enter our atmosphere at 90,000 mph, burning up 50 miles above Earth’s surface — a fiery end to a long journey!

Full Story: http://www.nasa.gov/topics/solarsystem/features/watchtheskies/quadrantids_2012.html

The Geminid Meteor Shower Rounds Off 2011

December 9, 2011 Leave a comment

2011 has been quite a year, both terrestrial and otherwise. This week sees the last of the big scheduled astronomical happenings of the year in the form of the Geminid meteor shower.

This shower is one of the yearly standbys along with the Perseids that are always sure to produce. The Geminids have a long peak centered on the morning of December 14th when an idealized Zenithal Hourly Rate (ZHR) of up to 120 meteors per hour may be seen.

Problems will arise, however, from an 82% illuminated waning gibbous Moon in the adjacent constellation of Cancer. Rising roughly around 10PM local on the night of the peak, this makes for the worst possible Moon phase as it’ll be high and bright in the early AM hours, just as the meteor shower is getting into high gear. But as always, I wouldn’t let that stop you from looking!

Full Story: http://www.meteorwatch.org/2011/12/07/the-geminid-meteor-shower-rounds-off-2011/

Leonids Meteor Shower 2011

November 17, 2011 Leave a comment

(Check out Steve Owens’ WordPress site, Dark Sky Diary, at http://darkskydiary.wordpress.com/)

On the night of 17/18 November 2011 the Leonids meteor shower reaches its peak. This annual performer is associated with Comet Temple-Tuttle, which orbits the Sun once every 33 years leaving a trail of debris as it goes. Once a year the Earth passes through this trail, and we see a meteor shower.

This year’s Leonids shower is hampered by the last quarter Moon which sits just to the right of the radiant of the Leonids, in Leo. Despite this there is good reason to observe the shower this year, as the International Meteor Organisation suggest there might be as many as three peaks of activity.

Full Story: http://darkskydiary.wordpress.com/2011/11/10/leonids-meteor-shower-2011/

Weekend Orionid Meteor Shower

October 21, 2011 Leave a comment

Earth is about to pass through a stream of debris from Halley’s comet, source of the annual Orionid meteor shower.  Forecasters expect more than 15 meteors per hour to fly across the sky on Saturday morning, Oct. 22nd, when the shower peaks.

“Although this isn’t the biggest meteor shower of the year, it’s definitely worth waking up for,” says Bill Cooke of the NASA Meteoroid Environment Office. “The setting is dynamite.”

Orionids are framed by some of the brightest and most beautiful constellations in the night sky. The meteors emerge from mighty Orion, the shower’s glittering namesake.  From there they streak through Taurus the Bull, the twins of Gemini, Leo the Lion, and Canis Major–home to Sirius, the most brilliant star of all.

This year, the Moon and Mars are part of the show.  They’ll form two vertices of a celestial triangle in the eastern sky on Saturday morning while the shower is most active; Regulus is the third vertex.  Blue Regulus and red Mars are both approximately of 1st magnitude, so they are easy to see alongside the 35% crescent Moon.  Many Orionids will be diving through the triangle in the hours before dawn.

Full Story: http://science.nasa.gov/science-news/science-at-nasa/2011/20oct_orionids/