Comets

"Appearing like a "blowtorch in the sky,"

It lit the night, and thus the naked eye

At that time had no trouble in discerning

What seemed for all the world to be a burning

Bit of heaven, a rending of the veil

Of the firmament, though in fact the tail,

Composed of meteoric dust and gas,

Held little to combust, so that it was

Merely one more reflection of sunlight"

George Bradley - The Year of the Comet

VIDEOS:

NASA Briefs Media on Comet Flyby. News conference held Feb. 15 following the flyby of comet Tempel 1 by the Stardust-NExT spacecraft on Valentine's Day, Feb. 14. The spacecraft's closest approach was a distance of 112 miles. Participants are: Ed Weiler, NASA's associate administrator, Science Mission Directorate, Washington; Joe Veverka, Stardust-NExT principal investigator, Cornell University; Tim Larson, Stardust-NExT project manager, NASA's Jet Propulsion Laboratory, Pasadena, Calif.; Don Brownlee, Stardust-NExT co-investigator, University of Washington, Seattle; and Pete Schultz, Stardust-NExT co-investigator, Brown University.

First impressions of Stardust-NExT flyby of comet Tempel 1. Scientists reveal sights and sounds of comet Tempel 1 flyby.

Giotto Flyby of Halley's Comet (1986.03.14). Images of comet Halley's nucleus taken by the Halley Multicolour Camera on board ESA's Giotto spacecraft were processed to produce this video sequence depicting the close fly-by of the comet on March 14, 1986, the first-ever close encounter of a comet's nucleus.

NEWS:

Comet Lovejoy Plunges In To The Sun And Survives - December 16, 2011

This morning, an armada of spacecraft witnessed something that many experts thought impossible. Comet Lovejoy flew through the hot atmosphere of the sun and emerged intact. "It's absolutely astounding," says Karl Battams of the Naval Research Lab in Washington DC. "I did not think the comet's icy core was big enough to survive plunging through the several million degree solar corona for close to an hour, but Comet Lovejoy is still with us."

The comet's close encounter was recorded by at least five spacecraft: NASA's Solar Dynamics Observatory and twin STEREO probes, Europe's Proba2 microsatellite, and the ESA/NASA Solar and Heliospheric Observatory. The most dramatic footage so far comes from SDO, which saw the comet go in (movie) and then come back out again (movie).

Science Paper Details NASA Epoxi Flyby of Hyper Comet - June 16, 2011

Comet Hartley 2's hyperactive state, as studied by NASA's EPOXI mission, is detailed in a new paper published in this week's issue of the journal Science.

After visiting a comet and imaging distant stars for hints of extrasolar planets, you could say the spacecraft used for EPOXI had seen its fair share of celestial wonders. But after about 3.2 billion miles (5.1 billion kilometers) of deep space travel, one final wonder awaited the mission's project and science teams. On Nov. 4, 2010, the EPOXI mission spacecraft flew past a weird little comet called Hartley 2.

Forensic Sleuthing Ties Ring Ripples to Impacts - March 31, 2011

Like forensic scientists examining fingerprints at a cosmic crime scene, scientists working with data from NASA's Cassini, Galileo and New Horizons missions have traced telltale ripples in the rings of Saturn and Jupiter back to collisions with cometary fragments dating back more than 10 years ago.

The ripple-producing culprit, in the case of Jupiter, was comet Shoemaker-Levy 9, whose debris cloud hurtled through the thin Jupiter ring system during a kamikaze course into the planet in July 1994. Scientists attribute Saturn's ripples to a similar object – likely another cloud of comet debris -- plunging through the inner rings in the second half of 1983. The findings are detailed in a pair of papers published online today in the journal Science.

NASA Stardust Spacecraft Officially Ends Operations - March 25, 2011

PASADENA, Calif. -- NASA's Stardust spacecraft sent its last transmission to Earth at 4:33 .m. PDT (7:33 p.m. EDT) Thursday, March 24, shortly after depleting fuel and ceasing operations. During a 12-year period, the venerable spacecraft collected and returned comet material to Earth and was reused after the end of its prime mission in 2006 to observe and study another comet during February 2011.

The Stardust team performed the burn to depletion because the comet hunter was literally running on fumes. The depletion maneuver command was sent from the Stardust-NExT mission control area at Lockheed Martin Space Systems in Denver. The operation was designed to fire Stardust's rockets until no fuel remained in the tank or fuel lines. The spacecraft sent acknowledgment of its last command from approximately 312 million kilometers (194 million miles) away in space.

"This is the end of the spacecraft's operations, but really just the beginnings of what this spacecraft's accomplishments will give to planetary science," said Lindley Johnson, Stardust-NExT and Discovery program executive at NASA Headquarters in Washington. "The treasure-trove of science data and engineering information collected and returned by Stardust is invaluable for planning future deep space planetary missions."

NASA Comet Hunter Spots Its Valentine - Jan. 26, 2011

NASA's Stardust spacecraft has downlinked its first images of comet Tempel 1, the target of a flyby planned for Valentine's Day, Feb. 14. The images were taken on Jan. 18 and 19 from a distance of 26.3 million kilometers (16.3 million miles), and 25.4 million kilometers (15.8 million miles) respectively. On Feb. 14, Stardust will fly within about 200 kilometers (124 miles) of the comet's nucleus.

"This is the first of many images to come of comet Tempel 1," said Joe Veverka, principal investigator of NASA's Stardust-NExT mission from Cornell University, Ithaca, N.Y. "Encountering something as small and fast as a comet in the vastness of space is always a challenge, but we are very pleased with how things are setting up for our Valentine's Day flyby."

NASA's Stardust Burns For Comet - 18 Feb., 2010

Just three days shy of one year before its planned flyby of comet Tempel 1, NASA's Stardust spacecraft has successfully performed a maneuver to adjust the time of its encounter by eight hours and 20 minutes. The delay maximizes the probability of the spacecraft capturing high-resolution images of the desired surface features of the 2.99-kilometer-wide (1.86 mile) potato-shaped mass of ice and dust.

With the spacecraft on the opposite side of the solar system and beyond the orbit of Mars, the trajectory correction maneuver began at 5:21 p.m. EST (2:21 p.m. PST) on Feb. 17. Stardust's rockets fired for 22 minutes and 53 seconds, changing the spacecraft's speed by 24 meters per second (54 miles per hour).

NASA Releases Images of Man-Made Crater on Comet - Feb. 15, 2011

NASA's Stardust spacecraft returned new images of a comet showing a scar resulting from the 2005 Deep Impact mission. The images also showed the comet has a fragile and weak nucleus.

The spacecraft made its closest approach to comet Tempel 1 on Monday, Feb. 14, at 8:40 p.m. PST (11:40 p.m. EST) at a distance of approximately 178 kilometers (111 miles). Stardust took 72 high-resolution images of the comet. It also accumulated 468 kilobytes of data about the dust in its coma, the cloud that is a comet's atmosphere. The craft is on its second mission of exploration called Stardust-NExT, having completed its prime mission collecting cometary particles and returning them to Earth in 2006.

Comet Hunter's First Images on the Ground - Feb. 15, 2011

Mission controllers at NASA's Jet Propulsion Laboratory, Pasadena, Calif., have begun receiving the first of 72 anticipated images of comet Tempel 1 taken by NASA's Stardust spacecraft.

The first six, most distant approach images are available at http://www.nasa.gov/stardust and http://www.jpl.nasa.gov. Additional images, including those from closest approach, are being down linked in chronological order and will be available later in the day.

NASA's NEOWISE Completes Scan for Asteroids and Comets - Feb. 1, 2011

NASA's NEOWISE mission has completed its survey of small bodies, asteroids and comets, in our solar system. The mission's discoveries of previously unknown objects include 20 comets, more than 33,000 asteroids in the main belt between Mars and Jupiter, and 134 near-Earth objects (NEOs). The NEOs are asteroids and comets with orbits that come within 45 million kilometers (28 million miles) of Earth's path around the sun.

NEOWISE is an enhancement of the Wide-field Infrared Survey Explorer, or WISE, mission that launched in December 2009. WISE scanned the entire celestial sky in infrared light about 1.5 times. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets close to Earth.

Sungrazing Comet - 02 Jan. 2010

Today, a bright comet is approaching the sun for a perilous close encounter, and it probably will not survive. The comet was

discovered by an amateur astronomer monitoring images from NASA's STEREO-A spacecraft. The Solar and Heliospheric

Observatory (SOHO) has a good view of the comet's approach and images are being posted on http://spaceweather.com

Links to Comet Websites:

Southern Comets - (Aus) Interesting website by Michael Mattiazzo who specialises in comets including observing data and photography.

Cometography.com - All things cometary by Gary Kronk including current and future comets, comets of the past and a catalogue of periodic comets.