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How Much of ISON Survived Its Closest Approach To the Sun?
SternisheFan writes "This Ars Technica article examines what may be left of ISON and contains a detailed animated GIF from the NASA STEREO Ahead spacecraft. 'It looks like comet ISON, or most of it, did not survive its encounter with the Sun yesterday, when it made a close approach at just 1.2 million kms from that fiery surface. This distance may seem large, but it is close enough to have subjected the comet to temperatures of around 2,700C. To survive such a close shave with the Sun may sound unlikely, but a few other sungrazing comets have managed the feat during even closer passes. So some people hoped ISON would perform a death-defying stunt and emerge intact. ISON did not leave us without a final serving of mystery though. Soon after reaching its nearest point to the Sun (known as perihelion), there was no sign of it emerging afterwards. Twitter and news agencies were alight, lamenting its loss and assuming it disintegrated—RIP ISON. But then, moments later, new images emerged showing a hint of something appearing on the other side of the Sun. Was this still a diminished comet ISON or a ghostly version of its former self? Well, even comet experts are not sure.'"
Video from NASA -
http://www.jpl.nasa.gov/video/index.php?id=1188
Muchas Gracias, Señor Edward Snowden !
in 1986...
If you could reason with religious people, there would be no religious people
It's like they has their own 'snow physics' or somethin'.
Spent All My Mod Points
The reason for why the comet appears to be so huge is the massive coma around the core as well as the tail originating from the core and scattering like a bowwave from a ship it extends and expands the further away it is from the source. The sudden seemingly increase in size of the tail when ISON re-appears above the sun comes from the sudden change of direction and the new direction how the ejected material is forced away from the core by the solar wind.
Most comets have a nucleus (the center of a comet) that is less than about 6 miles (10 km) wide. The size of a comet changes depending on how close it is to the sun. As a comet gets closer to the sun, the ices on the surface of its nucleus vaporize and form a cloud called a coma around the nucleus that can expand out to 50,000 miles (80,000 km). A tail also forms on a comet as it approaches the sun. Comet tails can be over 600,000 miles (1 million km) long.
An awesome gif indeed. A little closer to home is ....
http://www.dailygalaxy.com/my_weblog/2013/12/image-of-the-day-a-spectacular-meteor-streaking-through-the-aurora-borealis.html
Only if you mess with it's sister.
So many idiots, so few comets.
Table-ized A.I.
Probably a stupid question - but wouldn't the steam/plasma presumably have the same orbit as the original solid mass; similarly presumably wouldn't the solar wind blow the mass away fairly evenly - meaning in a long long time, it'll cool, condense and potentially (slowly) pull itself back together?
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The ejected material could come off at a significant velocity, so it wouldn't have quite the same orbit.
Solar wind (and light pressure) have more effect on small particles than large ones, since they act based on surface area (r^2) against mass (r^3). This is why the solar wind can sweep dust out of the solar system, but not planets.
There is also drag from the corona to consider. The comet effectively did an air dip.
TL;DR Any lost material was either blown out into space, or fell into the sun. Either way, this comet will not 'pull itself back together'
What emerged from the other side was almost, but not quite, entirely unlike tea.
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Remained intact and still moving
moox. for a new generation.
In most the major religions that have Sun as a diety ( Ancient Egyptian, Aztec, Roman, Greek, Chinese, Bhuddist)
I may be an American citizen but I am still a Chinese, by ethnicity.
Someone must have forgotten to tell me that the Sun is a diety.
Muchas Gracias, Señor Edward Snowden !
iSon may have survived a close encounter with the intense heat of the Sun . . . but it won't survive the intense heat of Apple's IP lawyers.
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
Ri Gong Tai Yang Xing Jun in Chinese mythology is "Grandfather Sun"
Why don't you go ask 100 Chinese and see how many of them ever heard of that "Ri Gong Tai Yang Xing Jun" ?
That character is one of the many many "minor characters" inside the Chinese fiction "Tale of the Monkey God"
Even the "Niu Mo Wang" (the Buffalo King), another character from the same tome, is more "famous" than that "Ri Gong Tai Yang Xing Jun" and yet, nobody, at least none of the Chinese that I know of, pray to that "Buffalo King".
Muchas Gracias, Señor Edward Snowden !
Not to be confused with the spectacular comet Lovejoy (2011). Both were discovered by the same guy so bear his name.
Lovejoy (2013) isn't as bright (barely visible to the naked eye), but should be easily visible with binoculars. It made its closest approach to Earth on Nov 19 and will reach perihelion (closest approach to the sun) Dec 25. It's fairly high up in the Northern hemisphere sky right now.
http://earthsky.org/space/how-to-see-comet-lovejoy-c2013-r1-charts-photos
Look, you asked how to define the temperature in vacuum and I answered
Put in a good number of assumptions and, based on them, one (with enough skill in the craft) will be able to estimate the internal temperature.
Of course it will still be an estimate and nothing more (one doesn't need to ask, it's only natural that precise data could be obtained only if you have unambigous direct observation of the phenomenon - and not even then)
Other than that, yes, the black-body radiation is correct for all macroscopic bodies (be them in one piece or crumbling) - the only requirements are: that body to expose a surface, be made of enough particles to display a statistical behavior and be at thermal equilibrium.
There was this guy, Plank, that put his name at stake on the correctness of it: to date, nobody ashamed him (his initial estimation of the constant was within 1.2% of the more precise value we accept today, which is quite remarcable IMHO)
Questions raise, answers kill. Raise questions to stay alive.