Comet Lovejoy Plunges Into the Sun and Survives

boldie writes with a link to NASA's account of comet Lovejoy's close encounter with the sun. Excerpting: "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. ... 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)." Here are larger QuickTime versions of the comet's entrance (22MB) and exit (26MB).

Comments

Misleading title

[aneroid]

Sounds a lot more sensational when you compare the title's "comet plunges into sun and survives" event vs the actual "comet flew through hot atmosphere of the sun".

/. worthy event nevertheless.

Re:Misleading title

[schroedingers_hat]

note to self, read preview when it comes up

Re:Misleading title

[MaskedSlacker]

No you couldn't.

At a certain point you'd reach neutral bouyancy and stop sinking (ignoring the part about you vaporizing from the temperature). This is still not the same as there being a surface (and in point of fact is COMPLETELY unrelated to what is usually referred to by the term "surface of the sun"). There is no meaningful line of demarcation between "below the surface" and "above the surface," and the term surface NECESSARILY implies a demarcation. The use of the term "surface" in the case of stars (and gas giants) is purely terrestrial metaphor, and it's fine as far as that goes--but only that far. Take the metaphor further (as my parent did in taking it literally), and you wind up reaching physically absurd conclusions (as you also have).

As for tomatoes, all I care about is that they're fucking delicious.

You'd be better off trying to claim that black holes have a surface. They don't, but at least they do have a clear demarcation between above and below their "surface." Stars do not.

FWIW, real astrophysicists define the surface of the sun as the radius which equals an optical depth of 2/3. This is a useful demarcation (though not a terribly clear one, since the optical depth is wavelength dependent) for observational purposes, but not for kinematic ones (such as when talking about comets flying into, and out of, the sun).

Re:Misleading title

[JTW]

A thought experiment worthy.

If you took a ball of Iron the size of say planet Earth, and it were to plunge into the heart of the Sun. What would be the result.. a Nova, SuperNova.. fizzle.

And what if it were slightly off target and merely circled the center for a while.. would it retain its shape or spinout into a smeared ball of plasma.. undoing the star?
Something somewhat like this probably already happened.. the Lithium content of our star for example.. guess it just wasn't significant emough.

I'm surprised they're surprised.

[jd]

Basic chemistry tells us that heat transfer isn't instantaneous, that solid objects remain at melting point until fully melted, and that heat != temperature. It's why you can walk over hot coals without burning yourself. The composition of the comet would be easy to determine, since absorption spectrometry will tell you what the tail is made of. We also know, from the Giotto probe, that comets don't evaporate from the outside. That was one of the biggest blunders in the mission. Never, ever make assumptions in science because it WILL bite you. Facts are the only acceptable currency.