Universe Today » Comets

Crescent Earth as Seen by Comet Chasing Spacecraft

Nancy Atkinson — Thu, 12 Nov 2009 22:34:34 +0000

Title this one "Rich Blue Crescent" (as opposed to Pale Blue Dot.) This spectacular image of our home planet was captured by the OSIRIS instrument on ESA's Rosetta comet chaser today (November 12) at 12:28 GMT from about 633,000 km as the spacecraft approached Earth for the third and final swingby. Closest approach is due at 07:45 GMT, on November 13. You can follow Rosetta's progress at ESA's Rosetta site and the Rosetta Blog.

© nancy for Universe Today, 2009. | Permalink | 7 comments | Add to del.icio.us
Post tags: Comets, Earth Observation, rosetta

Feed enhanced by Better Feed from Ozh

Rosetta to Make Final Earth Flyby Nov. 13th

Nicholos Wethington — Wed, 04 Nov 2009 18:44:33 +0000

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 the rest of Rosetta to Make Final Earth Flyby Nov. 13th (314 words)

Feed enhanced by Better Feed from Ozh

Mini Comets Ejected from Comet Holmes Caused Outburst

Nancy Atkinson — Wed, 16 Sep 2009 00:05:00 +0000

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.
(...)
Read the rest of Mini Comets Ejected from Comet Holmes Caused Outburst (446 words)

Feed enhanced by Better Feed from Ozh

Amino Acid Found in Stardust Comet Sample

Nancy Atkinson — Mon, 17 Aug 2009 19:38:30 +0000

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."
(...)
Read the rest of Amino Acid Found in Stardust Comet Sample (406 words)

Feed enhanced by Better Feed from Ozh

Half Comet-Half Asteroid a Fluke? Nope

Nancy Atkinson — Wed, 05 Aug 2009 22:14:18 +0000

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.
(...)
Read the rest of Half Comet-Half Asteroid a Fluke? Nope (312 words)

Feed enhanced by Better Feed from Ozh

Newly Discovered Cometary Route Sneaks Past Jupiter, but Decreases Risk of Earth Impacts

Anne Minard — Thu, 30 Jul 2009 18:01:26 +0000

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)

(...)
Read the rest of Newly Discovered Cometary Route Sneaks Past Jupiter, but Decreases Risk of Earth Impacts (747 words)

Feed enhanced by Better Feed from Ozh

Sub-surface Oceans In Early Comets Suggest Possible Origin of Life

Brian Ventrudo — Thu, 30 Jul 2009 17:48:41 +0000

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.

(...)
Read the rest of Sub-surface Oceans In Early Comets Suggest Possible Origin of Life (299 words)

Feed enhanced by Better Feed from Ozh

1908 Tunguska Event Caused by Comet, New Research Reveals

Nancy Atkinson — Wed, 24 Jun 2009 19:46:36 +0000

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.
(...)
Read the rest of 1908 Tunguska Event Caused by Comet, New Research Reveals (529 words)

Feed enhanced by Better Feed from Ozh

Ice on the Moon? NASA, ISRO May Collaborate to Find Out

Nancy Atkinson — Tue, 02 Jun 2009 00:44:07 +0000

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.
(...)
Read the rest of Ice on the Moon? NASA, ISRO May Collaborate to Find Out (333 words)

Feed enhanced by Better Feed from Ozh

Catching Up With Comet Yi-SWAN

Tammy Plotner — Tue, 14 Apr 2009 17:05:06 +0000

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 the rest of Catching Up With Comet Yi-SWAN (167 words)

Feed enhanced by Better Feed from Ozh

New Comet Yi-SWAN

Tammy Plotner — Thu, 09 Apr 2009 00:58:32 +0000

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 the rest of New Comet Yi-SWAN (215 words)

Feed enhanced by Better Feed from Ozh

Was the Tunguska Fireball a Comet Chemical Bomb?

Ian O'Neill — Fri, 27 Mar 2009 20:23:34 +0000

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…
(...)
Read the rest of Was the Tunguska Fireball a Comet Chemical Bomb? (332 words)

Feed enhanced by Better Feed from Ozh

Comet Lulin Approaches M44 and Eskimo Nebula

Tammy Plotner — Sun, 01 Mar 2009 16:46:12 +0000

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 the rest of Comet Lulin Approaches M44 and Eskimo Nebula (400 words)

Feed enhanced by Better Feed from Ozh

Comet Lulin Video – Watch the Outgassing Process

Tammy Plotner — Thu, 26 Feb 2009 16:06:55 +0000

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 the rest of Comet Lulin Video – Watch the Outgassing Process (221 words)

Feed enhanced by Better Feed from Ozh

How To See Comet Lulin

Nancy Atkinson — Tue, 24 Feb 2009 17:38:07 +0000

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.
(...)
Read the rest of How To See Comet Lulin (274 words)

Feed enhanced by Better Feed from Ozh

Swift Spacecraft Keeping an Eye on Comet Lulin

Nancy Atkinson — Fri, 20 Feb 2009 19:15:47 +0000

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!
(...)
Read the rest of Swift Spacecraft Keeping an Eye on Comet Lulin (551 words)

Feed enhanced by Better Feed from Ozh

Last Summer's Fireball in Pieces on the Ground?

Anne Minard — Fri, 13 Feb 2009 18:49:11 +0000

: The Bejar bolide photographed from Torrelodones, Madrid, Spain. The incoming fireball is the streak to the right of the floodlit house. The bright light at the top is the overexposed Moon. Credit: J. Perez Vallejo/SPMN.

Astronomers have analyzed the cometary fireball that blazed across the sky over Europe last year and concluded it was a dense object, about a meter (3.2 feet) across and with a mass of nearly two tons – large enough that some fragments probably survived intact and fell to the ground as meteorites.

Last July, people in Spain, Portugal and France watched the brilliant fireball produced by a boulder crashing down through the Earth’s atmosphere. In a paper to be published in the journal Monthly Notices of the Royal Astronomical Society, astronomer Josep M. Trigo-Rodríguez, of the Institute of Space Sciences in Spain, and his co-authors present dramatic images of the event. The scientists also explain how the boulder may originate from a comet which broke up nearly 90 years ago, and suggest that chunks of the boulder (and hence pieces of the comet) are waiting to be found on the ground.

(...)
Read the rest of Last Summer's Fireball in Pieces on the Ground? (420 words)

Feed enhanced by Better Feed from Ozh

Comet C/2007 N3 Lulin – A Twist In The Tail

Tammy Plotner — Mon, 02 Feb 2009 01:24:29 +0000

When Chi-Sheng Lin of Taiwan's Institute of Astronomy captured three images on July 11, 2007 with something strange in them, it was first believed he'd picked up just another asteroid. But, by July 17 astronomers in Table Mountain Observatory, California were noticing a coma 2-3" across, with a bright central core. That's not an asteroid… That's a comet! And now it's a comet that's doing something very strange… (...)
Read the rest of Comet C/2007 N3 Lulin – A Twist In The Tail (343 words)

Feed enhanced by Better Feed from Ozh

Comet Lulin is On the Way!

Nancy Atkinson — Wed, 14 Jan 2009 19:48:35 +0000

A new comet is swinging around the sun, and soon it will be more visible to stargazers, perhaps even with the naked eye. Both professional and amateur astronomers have been tracking this unusual comet, named Comet Lulin. Thanks to amateur astronomer Gregg Ruppel, who lives in the St. Louis, Missouri area for sharing images he has acquired of Comet Lulin. Gregg took the image above on January 11, 2009. The most interesting characteristic of this comet is its orbit. Lulin is actually moving in the opposite direction as the planets, so its apparent velocity will be quite fast. Estimates are it will be moving about 5 degrees a day across the sky, so when viewed with a telescope or binoculars, you may be able to see the comet's apparent motion against the background stars. This is quite unusual! Today, January 14, the comet is at perihelion, closest to the sun. As it moves to its closest approach to Earth on February 24, Lulin is expected to brighten to naked-eye visibility in rural areas, (at best about magnitude 5 or 6) and will be observable low in the sky in an east-southeast direction before dawn.
(...)
Read the rest of Comet Lulin is On the Way! (222 words)

Feed enhanced by Better Feed from Ozh

Stardust and Aerogel Return Home Again

Nancy Atkinson — Tue, 13 Jan 2009 00:21:43 +0000

Remember the Stardust mission that returned samples of comet dust back to Earth in 2006? The spacecraft dropped off a capsule containing samples of a comet's coma and interstellar dust particles, but the spacecraft "bus" is still out there in an elongated orbit of the sun. It will come home again, swinging by Earth on January 14, at 19:40 UTC (12:40 pm PST), getting a gravity assist from the home planet as it flies approximately 5713 miles (9200 kilometers) from the Earth’s surface. But the spacecraft isn't just wandering the solar system with nothing to do. It has a new job and a new mission. Called Stardust NExT, (New Exploration of Tempel 1) the spacecraft will re-survey comet Tempel 1 – the comet that the Deep Impact mission left a mark on — encountering the comet on Feb. 14, 2011.

And remember aerogel – the wispy material that collected the comet dust? Turns out this stuff can come home, too: into homes and other buildings as a super-insulating material. Engineers say using aerogel as an insulator can increase the thermal insulation factor of a wall by over 40%!
(...)
Read the rest of Stardust and Aerogel Return Home Again (465 words)

Feed enhanced by Better Feed from Ozh

2012: No Comet

Ian O'Neill — Mon, 22 Dec 2008 05:45:53 +0000

According to 2012 doomsday proponents, something big is out to get us. By "something big" I mean some uncontrollable cosmic entity (i.e. Planet X, Nibiru or a "killer" solar flare), and by "us" I mean the whole of planet Earth. Pinning 2012 doomsday scenarios on the end of the ancient Mayan "Long Count" calendar appears to be growing momentum amongst authors, websites, documentaries and (my personal favourite) YouTube videos. According to them, something bad is going to happen on or around December 21st 2012. Probably the most interesting difference between the 2012 doomsday scenario and the doomsday prophecies of the past is that almost every possible (and impossible… or implausible) harbinger of doom is being suggested as a planet killer.

So, in this sixth article addressing another astronomical doomsday scenario, I will look at the theory that there is a comet currently out there in deep space, slowly making its final approach on its parabolic orbit toward Earth. But before you get worried, you'll be glad to hear that the 2012 cometary impact theory is as watertight as a teabag; there is no object observed out there and there is certainly no evidence to suggest there could be a comet impact in 2012… and here's why…
(...)
Read the rest of 2012: No Comet (1,847 words)

Feed enhanced by Better Feed from Ozh

Swift Detects X-Ray Emissions from Comets

Ian O'Neill — Thu, 04 Dec 2008 05:46:45 +0000

Things appeared to get a little strange in the field of X-ray astronomy when the NASA/ESA ROSAT observatory started seeing emissions from a series of comets. This discovery in 1996 was a conundrum; how could X-rays, more commonly associated with hot plasmas, be produced by some of the coldest bodies in the Solar System? In 2005, NASA's Swift observatory was launched to look out for some of the most energetic events in the observable Universe: gamma-ray bursts (GRBs) and supernovae. But in the last three years, Swift has also proven itself to be an expert comet hunter.

If X-rays are usually emitted by multi-million Kelvin plasmas, how can X-rays possibly be generated by comets composed of ice and dust? It turns out there is an interesting quirk as comets interact with the solar wind within 3AU from the solar surface, allowing instrumentation designed to observe the most violent explosions in the Universe to also study the most elegant objects closer to home…
(...)
Read the rest of Swift Detects X-Ray Emissions from Comets (389 words)

Feed enhanced by Better Feed from Ozh

A New Type of Comet? And Where Did It Come From?

Nancy Atkinson — Tue, 02 Dec 2008 21:56:29 +0000

All comets are about the same, right? Not necessarily. Astronomer David Schleicher has been studying 150 comets, measuring the abundances of five different molecules in each comet. One of these comets, Comet 96P/Machholz 1 was different from all the rest, showing an extremely unusual chemistry. Schleicher believes the anomalous composition may reveal the existence of a new class of comets. What makes Machholz 1 different is that the molecule cyanogen, CN, is extremely depleted. In Machholz 1, CN is missing by about a factor of 72 from the average of other comets, i.e., only a little above one percent of normal. “This depletion of CN is much more than ever seen for any previously studied comet, and only one other comet has even exhibited a CN depletion,” said Schleicher. The cause of the chemical anomaly is unknown.

However Schleicher, a planetary astronomer at the Lowell Observatory has come up with three intriguing scenarios to explain origins of Machholz 1, and each one will yield important but differing new constraints on the formation or evolution of comets.
(...)
Read the rest of A New Type of Comet? And Where Did It Come From? (679 words)

Feed enhanced by Better Feed from Ozh

New Telescope on the Lookout for Near Earth Asteroids, Comets

Nancy Atkinson — Tue, 18 Nov 2008 22:23:10 +0000

A prototype telescope with an enhanced ability to find moving objects will soon be operational, and its mission will be to detect asteroids and comets that could someday pose a threat to Earth. The system is called Pan-STARRS (for Panoramic Survey Telescope and Rapid Response System) located on Haleakala mountain in Maui,Hawaii, and is the first of four telescopes that will be housed together in one dome. Pan-STARRS will feature the world's largest and most advanced digital camera, providing more than a fivefold improvement in the ability to detect Near Earth Asteroids and comets. "This is a truly giant instrument," said University of Hawaii astronomer John Tonry, who led the team developing the new 1.4-gigapixel camera. "We get an image that is 38,000 by 38,000 pixels in size, or about 200 times larger than you get in a high-end consumer digital camera." The Pan-STARRS camera will cover an area of sky six times the width of the full moon and it can detect stars 10 million times fainter than those visible to the naked eye.
(...)
Read the rest of New Telescope on the Lookout for Near Earth Asteroids, Comets (411 words)

Feed enhanced by Better Feed from Ozh

An Inside Look at Comet Holmes

Nancy Atkinson — Mon, 13 Oct 2008 20:25:49 +0000

The astronomy world buzzed in the Fall of 2007 when Comet Holmes – a normally humdrum, run-of-the-mill comet — unexpectedly flared and erupted. Its coma of gas and dust expanded away from the comet, extending to a volume larger than the Sun. Professional and amateur astronomers around the world turned their telescopes toward the spectacular event. Everyone wanted to know why the comet had suddenly exploded. The Hubble Space Telescope observed the comet, but provided few clues. And now, observations taken of the comet after the explosion by NASA's Spitzer Space Telescope deepen the mystery, showing oddly behaving streamers in the shell of dust surrounding the nucleus of the comet. The data also offer a rare look at the material liberated from within the nucleus. "The data we got from Spitzer do not look like anything we typically see when looking at comets," said Bill Reach of NASA's Spitzer Science Center at Caltech.
(...)
Read the rest of An Inside Look at Comet Holmes (607 words)

Feed enhanced by Better Feed from Ozh