Comets | Universe Today

The comet chasing spacecraft Rosetta will make its third and final swing by the Earth on November 13th to pick up more speed for the last part of a 10-year journey that lies ahead. Its mission is to place a lander on comet 67P/Churyumov-Gerasimenko and chase the comet for an entire year on its orbit around the Sun. The spacecraft will be visible to observers from the ground in certain locations on the Earth. This last flyby will increase the spacecraft's speed by 3.6 km/s (2.2 miles/s) with respect to the Sun, giving Rosetta the energy it needs to boost it to the outer regions of the Solar System. Read more…

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Comet 17P/Holmes caused a sensation in October and November 2007 when overnight, it brightened enough to be visible with the naked eye and became the largest cometary outburst ever witnessed. Using a special filter on the Canada- France- Hawaii Telescope in Hawaii, astronomers were able to peer inside Comet Holmes to determine why the comet became so bright. Images and animations show multiple fragments were ejected and rapidly flew away from the nucleus of comet Holmes.
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NASA scientists studying the comet samples returned by the Stardust spacecraft have discovered glycine, a fundamental building block of life. Stardust captured the samples from comet Wild 2 in 2004 and returned them to Earth in 2006. "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. "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."
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Back in 1996, astronomers discovered a strange object in the asteroid belt. They decided it was either a "lost" comet or an icy asteroid, as it ejected dust like a comet but had an orbit like an asteroid. No one had ever seen anything like the object, called 133P. Ever since it was found, astronomers have wondered if it was just an oddity — one of a kind. We now know it is not, and the discovery of more of these half asteroids/half comets means there is a new class of objects in our solar system.
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Astronomers have used the comet record — including 2001 RX14 (Linear) at left, captured in 2002 by the Sloan Digital Sky Survey — to model a new route for incoming comets that sneaks past Jupiter's gravity.

The pathway might even be the dominant one that delivers Oort Could comets on an Earth-bound trajectory, say the authors of a new study in Science this week — but if that's true, comets only rarely cause extinctions on Earth.

(Image credit: Mike Solontoi/University of Washington)

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A new study claims early comets contained vast interior oceans of liquid water that may have provided the ideal conditions for early life to form.

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The 1908 Tunguska event has always been mysterious and intriguing because no one has been able to fully explain the explosion that leveled 830 square miles of Siberian forest. But the latest research has concluded that the Tunguska explosion was almost certainly caused by a comet entering the Earth’s atmosphere. And how researcher Michael Kelly from Cornell University came to that conclusion is quite interesting: He analyzed the space shuttle's exhaust plume and noctilucent clouds.
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The debate has endured since the early 1960's: could there be water ice hiding in deep, dark craters near the Moon’s poles, left untouched by sunlight? Several spacecraft orbiting the moon have tried to peer into these craters to find out, but so far no definitive data has been obtained either way. But now NASA and the Indian Space Research Organization (ISRO) are looking to team up two spacecraft to try and answer the question once and for all. “When it happens, it is going to be a unique experiment and will be the first of its kind,” said Dr. Mylswamy Annadurai, project director for the Chandrayaan-I orbiter.
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Now that the Moon is out of the early evening sky, far northern observers are out in force hunting down Comet C/2009 Yi-SWAN… and it's there! In 10X50 binoculars it appears like a very faint, small globular cluster, but definitely has the signature of a comet in a 4.5" telescope. Surprisingly enough, it's not very hard to find. Would you like a hand? Read more…

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Are you ready for the new kid on the block? Its name is Comet Yi-SWAN and it's not going to be very long before it's easily within range of small telescopes and larger binoculars. So where is it at? Head out to the early morning skies for your best look, because it's rockin' with the Queen – Cassiopeia. Read more…

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Over a century ago, on June 30th, 1908 a huge explosion detonated over an unpopulated region of Russia called Tunguska. It is probably one of the most enduring mysteries of this planet. What could cause such a huge explosion in the atmosphere, with the energy of a thousand Hiroshima atomic bombs, flattening a forest the area of Luxembourg and yet leaving no crater? It is little wonder that the Tunguska event has become great material for science fiction writers; how could such a huge blast, that shook the Earth's magnetic field and lit up the Northern Hemisphere skies for three days leave no crater and just a bunch of flattened, scorched trees?

Although there are many theories as to how the Tunguska event may have unfolded, scientists are still divided over what kind of object could have hit the Earth from space. Now a Russian scientist believes he has uncovered the best answer yet. The Earth was glanced by a large comet, that skipped off the upper atmosphere, dropping a chunk of comet material as it did so. As the comet chunk heated up as it dropped through the atmosphere, the material, packed with volatile chemicals, exploded as the biggest chemical explosion mankind had ever seen…
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Have you ever wondered what it would be like to step into space and have a look at solar system objects in aspect? While we can view interesting and inspiring events like Comet Lulin's recent conjunction with Saturn, what we can't quite get our brains to wrap around it how it would appear in dimension. Thanks to some "magic" by Jukka Metsavainio and some of his own outstanding astrophotography – now we can… Read more…

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Roughly 38 million miles from Earth and traveling at a relative velocity of 140,000 miles per hour, the speedy Comet C/2007 N3 Lulin has caught our imaginations in a big way during the beginning months of the International Year of Astronomy. Right now, Comet Lulin has already sped past the Sun, slipped by stately Saturn from our point of view and is on a parabolic trajectory heading out from our solar system. This means it will never come back… Read more…

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We've received a few emails asking for more information about how to attempt to observe Comet Lulin. And Sky and Telescope has put out a great primer for seeing this green smudgeball in North America. Right now is the optimum time to try and see it. Sky and Telescope editor-in-chief Robert Naeye says Lulin should be at its best from Feb. 23 through the 28th. "In a very dark, unpolluted, natural night sky — such as few people see any more — the comet is dimly visible to the unaided eye," writes Naeye. "Even in a more light-polluted suburban sky, however, a good pair of binoculars will do the trick. But you have to know exactly where to look."

Start looking for Lulin after 9:00 pm (your local time) but the view will be better after 10:00 pm.
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The Swift spacecraft is doing double duty these days. Normally, the Gamma-ray Explorer satellite is on the lookout for high-energy outbursts and cosmic explosions. But now Swift is also monitoring Comet Lulin as it comes closer to Earth. For the first time, astronomers are seeing simultaneous ultraviolet and X-ray images of a comet. "The comet is releasing a great amount of gas, which makes it an ideal target for X-ray observations," said Andrew Read, also at Leicester. And the ultraviolet data shows that Lulin is also shedding a huge amount of water, about 800 gallons of water each second!
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