How Much of ISON Survived Its Closest Approach To the Sun? 84
A reader 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.'"
Re: (Score:2)
sorry, but in most the major religions that have Sun as a diety ( Ancient Egyptian, Aztec, Roman, Greek, Chinese, Bhuddist) , he's a dude. Your comets swing "the other way".
Someone must have forgotten to tell me ... (Score:2)
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.
Re:Someone must have forgotten to tell me ... (Score:4, Funny)
Ri Gong Tai Yang Xing Jun in Chinese mythology is "Grandfather Sun"
You should survey the Chinese ... (Score:2)
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".
Re: (Score:2)
my in-laws are chinese, so I have resident reference at home 8D
Some Chinese people from other asian countries outside China are more into the old myths. They don't worship these characters, but some know the mythologies. The Grandfather Sun (also called Taiyang Shen) is in Mahayana Bhuddist and Taoist texts too.
Re: (Score:2)
A Taoist might indeed worship the Sun Grandfather, they have rituals for doing so in their writings. And that minor deity appears in (Mahayana) Bhuddist writings, he's a part of that religion whether average Bhuddist remembers him or not. So he's a part of Chinese religions, even if you had to look up his name
Re: Please make up your mind, dude ! (Score:2)
It of course referred to ancient chinese people. The Chinese have been around for thousands of years, the beliefs of modern chinese are irrelevant. China is also a very big area in Asia with many different peoples. In any case I wouldn't expect any modern chinese to still be burdened by religion today, especially polytheist ones.
Re: (Score:2)
your reading comprehension skills are lacking, I only said they had this character as a "deity", which can and does include very very minor ones, and which does not even imply worship, just that they're on a list in someone's religion as being a deity. Aside from most Chinese probably being atheists, of the ones that have a religion most would be Mahaya Bhuddhists, and THAT religion does have the Grandfather Sun on the list of (very minor) deities. QED, you lose.
Re: (Score:2)
Re: (Score:2)
he's adopted!
Re: (Score:2)
I heard his grandson's book on how to make war is real popular these days.
Re: (Score:2)
Re: (Score:2)
Buddhists don't worship gods ...
Re: (Score:2)
yes hundreds of millions of Buddhists do just that. In many Bhuddist countries other gods are rolled into the religion. Many have ancestor whorship. Many revere and pray to the Bhudda himself as a god. Many revere the Dalai Lama as a deity, and to oversimplify his teachings one could say he is telling people how they can become a "god"
Re: (Score:2)
The concept of a god is in Buddism completely different than we name a god. It is only lack for a proper name that we call them gods. Most of them are as you correctly say mixed in from other religions. Most buddhists I know would call themselves atheists, as buddism is for them more a path for personal development than a religion.
Re: (Score:2)
you could say that for various sects of any religion including Christianity, different views of "god" ranging from just a concept to a "helpful sprite" to big meanie who has already predestinated some to burn in hell
Re: (Score:1)
sorry, but in most the major religions that have Sun as a diety ( Ancient Egyptian, Aztec, Roman, Greek, Chinese, Bhuddist) , he's a dude. Your comets swing "the other way".
Ah, yes. The ancient religion of "Chinese"...
Ewww, nothing left but (Score:1)
...comet brains
Watch for the Fan shaped tail (Score:4, Interesting)
Video from NASA -
http://www.jpl.nasa.gov/video/index.php?id=1188 [nasa.gov]
Re: (Score:2)
After watching several animated gif's of the event (like this one: http://arstechnica.com/science/2013/12/comet-ison-fizzles-but-theres-a-sting-in-the-tail/ [arstechnica.com]), I'm left a little perplexed. I was under the impression that as a comet approaches the Sun, the heat causes outgassing and evaporation, and the tail forms as the solar wind blows that away from the comet. Accordingly, I thought a comet's tail roughly always pointed away from the sun with maybe a slight curve due to momentum. But the gif's I'm seeing d
Re:So... (Score:5, Informative)
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 [dailygalaxy.com]
Re: (Score:3)
Maybe they should look for it (Score:5, Funny)
Re: (Score:2)
Or 1947, in Roswell, NM. Something involving a microwave oven and a supernova.
Re: (Score:2)
March, 1997.
Do you have your $5.75 and Nikes, and are ready to catch the outbound flight?
Them darn dirty snowballs... (Score:2)
No Hale Bopp "Koolaide" rerun? Rats! (Score:5, Funny)
So many idiots, so few comets.
i-Phone, i-Pad (Score:2)
Re:i-Phone, i-Pad (Score:4, Funny)
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.
Dumb question, but...? (Score:3)
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?
Re: (Score:1)
no, liquidus would make it spread out and become "atmosphere" of the sun. Also there is no cooler masses lying around for it to give it's heat to, so no to the 2nd question.
Re: (Score:2)
I would think the suns magnetosphere would redirect any plasma, and possibly water steam would be effected by it too.
No, and no (Score:4, Informative)
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'
Define survived (Score:1)
Define survived
Its not like it was alive or anything
Most of the non ice stuff will still be in pretty much the same orbit
Re: (Score:3)
Remained intact and still moving
2700 degC? (Score:2)
Re: (Score:2)
How do they define temperature? The show happens in vacuum, there is no thermal agitation.
Not quite vacuum but even if it would be so: black-body radiation [wikipedia.org] is a measure of temperature for radiative-only cases.
Re: (Score:2)
Re:2700 degC? (Score:5, Informative)
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 [wikipedia.org] 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 [wikipedia.org] to display a statistical behavior and be at thermal equilibrium.
There was this guy, Plank [wikipedia.org], 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)
Re: (Score:2)
Why it's named ISON (Score:1)
It Still Outshines Nothing
Really, really hot (Score:4, Informative)
What emerged from the other side was almost, but not quite, entirely unlike tea.
JSON? (Score:2, Funny)
There's still comet Lovejoy (Score:5, Interesting)
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 [earthsky.org]
Looks like it's finally gone: (Score:2)
"Previous reports of Comet ISON's death may have been somewhat exaggerated, but this time it looks like the real thing [death].
Remnants of the object once touted as the "comet of the century" passed through the viewing field of the Solar and Heliospheric Observatory in the wake of Thursday's close encounter with the sun -- and as it passed, the bright spot that survived grew dimmer and dimmer.
"I do think that something emerged from the sun, but probably a very small nucleus or 'rubble pile.' and I fear that
What I find really funny (Score:2)
Obligatory ... (Score:2)
Tidal forces (Score:1)