Halley's Comet Imaged As Transneptunian Object

An anonymous reader writes "The European Space Observatory has imaged Halley's Comet at the farthest point (past Neptune) in which such a 10-kilometer diameter iceball has ever been observed. To image a comet as a raven-black object, without its bright dust tail (coma), is equivalent to seeing a lump of coal at the distance between the Earth's poles and to do so in the evening twilight. The last gasp seen from Halley's Comet was 1991, when a gigantic explosion happened, providing it with an expanding, extensive cloud of dust for several months. It is not known whether this event was caused by a collision with an unknown piece of rock or by internal processes (a last 'sigh' on the way out). Halley has an orbital period just over 76 years and will return in 2062."

Comments

Couldn't have been a collision, methinks

[Jonas the Bold]

It is not known whether this event was caused by a collision with an unknown piece of rock or by internal processes (a last 'sigh' on the way out).

If they were able to image it, it seems they knew where it was, by mapping where it was going. If it had collided with something, it's trajectory would have changed.

So does this give us new insight as to how comets die? And if they die, how are they still comets? How does the solar system replenish its comet supply?

Re:Couldn't have been a collision, methinks

[tloh]

Even if the event was caused by internal processes, trajectory changes are still possible due to Newton's 3rd law of motion. A last 'sigh' may not generate as much momentum as a collision, but it should still have enough impulse to make determination of the exact nature of the event non-trivial.

Should we be worried about the solar system replenishing its comets? I don't think running out of comets should concern us Earth dwellers that much. In fact, it would be best to have as few of them as possible unless we want to go the way of the dinosours. Our technology gives us an edge over our Cretaceous-dwelling friends, but the resources needed for a comet defense force seem outrageous when you consider all the problems on Earth that need money, political will, and man power. Besides, Bruce Willis & gang are better suited for...well, almost anything else. damn! that movie sucked!

In case of slashdotting...

[Anonymous Coward]

Here's the image, in case it gets /.'ed:

. . . . . .
. , . . . . (the 2nd one)
. . . . . .

Re:In case of slashdotting...

[EvilTwinSkippy]

It's morse code for "So long and thanks for all the fish."

Re:Question

[jabbadabbadoo]

The spot was discovered by Robert Hooke in 1664. The spot is HUGE (large enough to hold to Earths) and back in the 15'th centurty it was much brighter. The red spot in the southern hemisphere has been there for about 400 years and is starting for fade.

Re:What's the fun...

[Anonymous Coward]

That's human curiosity, what allowed us to survive and evolve through ages. Give us some knowledge buried under a giant rock and we'll put huge efforts in removing that rock.
The same applies to the comet's tail: there's a chance to learn something by making observations without the comet tail hiding things.

Cool Fact

[Moridineas]

Almost 1000 years ago, Halley's Comet was overhead during the Battle of Hastings in the year 1066. That long ago, the comet was said to have virtually filled the sky it was so bright. It must have been perceived as a powerful omen.

Re:Cool Fact

[toxic666]

Wll, at least sometime around the Battle of Hastings. It appeared near Easter, 1066 and Harold was warned it was a BAD OMEN. Hastings was in September or October, 1066. The Bayeux Tapestry (yes, I've seen it) records the events and the comet appears well before the battle above Harold's minions warning him.

So shove your Cool Fact urban legend. Not even the Middle Ages records support your ignorant claim.

Astonishing

[Timesprout]

They can pick out such a small dark object at that distance. Makes me hope that maybe one day the Star Trek scenes where Picard asks Data for range to object and then has it on screen in living colour at 50 million Kilometres may one day become a reality.

The real reason for the telescope

[KingRob]

ESA's sekret plan is to point that baby at the Apollo landing site and prove once and for all, those lying Amerikanischer Schweinhund never made it to the moon!

Re:Question

[Jeremy Erwin]

The spot was discovered by Robert Hooke in 1664. The spot is HUGE (large enough to hold to Earths) and back in the 15'th centurty it was much brighter.

Really? You have some idea of of how the GRS appeared 200 years before Hooke (in the mid seventeenth century) inferred the rotational period of Jupiter? The earliest definitive observations of the GRS, btw, are those of Heinrich Schwabe (1831)

Slightly over-hyped

[panurge]

Everything else has been removed from the picture. In effect, in order to see the comet you have to know exactly where it is, and what all the other things are in the vicinity. It also took a lot of observation (hours) to get the picture.

It's a remarkable achievement, and shows what can be done with Earth-based telescopes, but it seems to be more proof of concept than practical.

Re:Slightly over-hyped

[MartyC]

True. Halley's Comet is ideal for this kind of observation because it has one of the most accurately known orbits of all comets of this kind of orbital period.
But you shouldn't see this as just a comet finding exercise (though it does prove the capabilities of the VLT rather well).
By analysing the image further it will be possible to determine whether there is any activity at this distance, or a residual dust cloud. Depending on what filters they used for the observation, they might be able to compare the "colour" of the nucleus with that observed by the spacecraft back in 1986 and look for changes. This might indicate a change in surface conditions at large distances form the sun.

just to clarify

[MartyC]

That should be European Southern Observatory (www.eso.org).

Explosion didn't involve Halley?

[meowsqueak]

Hmmm, I read that as a 'gigantic explosion' involving Halley's Comet, however it seems to involve Comet 57P/du Toit-Neujmin-Delporte according to one of the linked articles. Did I miss something?

Re:Explosion didn't involve Halley?

[rworne]

No you didn't, the Slashdot article is wrong. Halley's was only mentioned in the last sentence, and only then to show that it is Comet 1P.

Incorrect link or error in the article

[shanen]

The link that is described as referring to an event involving Halley's Comet is talking about a different comet. I should poke around for events actually involving Halley's, but I'll just settle for saying that I don't recall hearing anything unusual as it wandered away, and I'm actually rather skeptical we could see so much of it at that time (though the latest imaging is an impressive accomplishment).

Re:I saw it last time

[RobertB-DC]

In the end, I got a look at Mars, it looked like this:

.

except it was pink.

I'm happy to report that I was able to run your image through a high-tech image-enhancement system. To further aid in visualization, the edge definition has been increased as well.

Here is the new image:

o

Hope this helps!