Skip to comments.Astronomy Picture of the Day -- Comet Lovejoy: Sungrazing Survivor
Posted on 12/16/2011 9:18:57 PM PST by SunkenCiv
Explanation: Like most other sungrazing comets, Comet Lovejoy (C/2011 W3) was not expected to survive its close encounter with the Sun. But it did. This image from a coronograph onboard the sun-staring SOHO spacecraft identifies the still inbound remnants of the tail, with the brilliant head or coma emerging from the solar glare on December 16. The Sun's position, behind an occulting disk to block the overwhelming glare, is indicated by the white circle. Separated from its tail, Comet Lovejoy's coma is so bright it saturates the camera's pixels creating the horizontal streaks. Based on their orbits, sungrazer comets are thought to belong to the Kreutz family of comets, created by successive break ups from a single large parent comet that passed very near the Sun in the twelfth century. Most have been discovered with SOHO's cameras, but unlike many sungrazers, this one was first spotted by Australian astronomer Terry Lovejoy from an earth-based observatory. Comet Lovejoy is estmated to have come within 120,000 kilometers of the Sun's surface and likely had a large cometary nucleus to have survived its intense perihelion passage. Remarkable videos of the encounter from the Solar Dynamics Observatory can be found here.
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OK SO WE HUNT IT DOWN AND KILL IT.
NOTHIN’ LIKE PRACTICE!
"Comet" Lovejoy survived almost an hour in ove a million degrees of heat in the Sun's corona, 87K from the surface. Comets are balls of ice and snow.
Here's your Home Science Experiment: Place an ice cube in a pan under a 500 degree broiler for a half hour. Observe what happens.
Now, based on your observation, try to explain how "Comet" Lovejoy could possibly be made of ice.
Oh yeah, and for extra credit, explain why the Sun's X-Ray flux flatlined for two days during Lovejoy's approach.
That's one tough ice cube!
Fun with science. Melting follows a cube law for surface area/size. A comet has a hell of a lot of mass with a small surface area.
Also fun with science.... While the temperature of the individual molecules in the corona of the sun may be 10e6 degrees (F or C, at that temp it doesn't matter)... the density of them does.
You would die of explosive decompression before you burned to death, should you show up there, clothed as you were born.
All cooks know this kind of stuff. We have to deal with heat/ice/vaccuum/pressure stuff all of the time.
De Comet went true Desun, defeat before detail.
Would like to offer a theory and some fact. Matter being neither able to be created nor destroyed, (theory) the comet vaporized, the vapor continued on trajectory, and simply reassembled after leaving the Sun? Unknown, and speculation.
a distinction without a difference..
I am actually amazed that it emerged at all! :-)
Comets are not “balls of ice and snow”. Comets are rocks (or piles of smaller rocks) mixed with various hydrocarbons, also ammonia (NH3), water ice, and varying traces of other things (the green comet of a year or two ago was shedding chlorine, for example).
Comets shed their gases and liquids at different rates, depending on how deep in the body they are buried, and how much energy is received from the Sun. The number of times they’re able to do that has to do with the orbit and amount of gases and liquids they have at the beginning. Eventually they shed all of it and continue on a more stable but still eccentric orbit, remaining dark. Eventually they have one or more encounters with other bodies.
Asteroids are largely known from the asteroid belt between Mars and Jupiter, but the Earth-crossers are probably the rocky remains of comets, or were shed from comets. A number of the various annual meteor showers have been associated with specific comets, and continue to travel as a debris stream in one of the old paths taken by the parent comets.
Great posting of facts. Thanks.
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