I just received the Sky and Telescope AstroAlert about the discovery of NY40, and its approach to Earth. It will be visible in binoculars at mag. 9.3 on the evening of Aug. 17-18, near the double star Albireo.

Wow, it couldn't have chosen a better co-star.

<font size=-1>[Fixed syntax]</font>

<font size=-1>[ This Message was edited by: GrapesOfWrath on 2002-07-22 14:06 ]</font>

NY 40 Impact Risk Summary.

<font size=-1>[ This Message was edited by: Chip on 2002-07-22 14:40 ]</font>

Am I reading the chart right? It is to pass within 4500km of Earth's center? Huh?

And in 2059, it estimates .03 Earth radii?? This is a 640 meter object?

Is that right?

CJSF

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<font size=-1>[ This Message was edited by: Christopher Ferro on 2002-07-22 14:48 ]</font>

<font size=-1>[ This Message was edited by: Christopher Ferro on 2002-07-22 14:49 ]</font>

I think what it says is that that is the minimum distance predicted. The uncertainty of the prediction means there's an outside chance it could come closer than 1 Earth radius from the geocenter (IOW, impact). But that's just the outside edge. The greatest probabilities are for distances much farther from the center.

Or at least that's how I read it. I can't really tell for sure.

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...And that, my liege, is how we know the Earth to be banana-shaped. --Sir Bedevere

Yes, I believe I was right. This quote, taken from the link given on the page, explains it better:

Here's the page it's from: http://neo.jpl.nasa.gov/risk/doc/sentry.html

__________________
...And that, my liege, is how we know the Earth to be banana-shaped. --Sir Bedevere

Check out the JPL space calendar link, http://www.jpl.nasa.gov/calendar/#0010 and click on the August 19 asteroid event link. Give the java script a bit to load. Try out the tools.

Randy

FYI... more info about Albireo:
http://www.astro.uiuc.edu/~kaler/sow/albireo.html

On August 18, 2002, 2002 NY40 is predicted to come within about 0.003 AU of the Earth, according to NASA's Java-based Orbit Viewer. That's about 448,794 Km.

To give an feeling of how close NY40 might come, the Moon is 384,403 kilometers from Earth. NY40 might be circa 64,391 kilometers further away, but of course considerably smaller in size. It should be an interesting project for telescopic spotting.

Hmm...the moon will be past first quarter, so that's bad. But it's summer, so it's low in the sky, and Cygnus will be near zenith at midnight. I imagine we could get some looks at it before that too.

Yes. I sure do hope for a clear and dry night. Some friends and I are planning a little camping trip to get away from the city noise. If the clouds get annoying, there's always campfires and guitars [img]/phpBB/images/smiles/icon_smile.gif[/img]

Campfires and guitars - sounds like a scene from a film;

There they were, huddled around the incandsent glow of the now simmering campfire. Feeling the chill one of the campers puts some fresh coal on the campfire. He streches, yawns, then starts to relax to the sounds of a few freinds playing a gentle tune on their guitars.

All is quiet and there is nothing to break the mood of the evening except the occasional shooting star. But one of these shooting stars seems a little brighter than the others ...

Phobos

<font size=-1>[ This Message was edited by: Phobos on 2002-07-23 11:45 ]</font>

What about this one:

http://www.cnn.com/2002/TECH/space/0....ap/index.html

Are you ready to die under the flames of a planet killer?

1.2 mile is enough to crack the whole planet.

By the way, people are concerned as I never thought it could be (see the box "quick vote" on the same page).

Tonight I'm gonna party like it's 2019!

My browser **crashed** when I tried to vote. Is this a bad omen??????

I guess I should head over to Donnie's party [img]/phpBB/images/smiles/icon_smile.gif[/img]

I guess this is Prince (or, The Man With No Name)!

Carpe Diem!!! The end is near. [img]/phpBB/images/smiles/icon_smile.gif[/img]

(*) Gosh, this will make the day of all the maniacs of the world. If you liked 1999 you'll love 2019!

Here's the figure: nearly half of the voters are concerned about. This is surprising, since we know the average citizen don't give a darn to space affairs.

It's less than a half now...
But I guess everybody cares about space affairs if they involve a 2 kilometer sized rock falling on your head... [img]/phpBB/images/smiles/icon_lol.gif[/img]

No it is not! It is approximately 1/5th the size of the "dinosaur killer" of 65,000,000 years ago.

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Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson

If you took a bowling ball as the Earth, then the 1.2 mile asteroid would be ... let's see ... no, there's nothing that small.

Let's see, if the earth were a ten foot iron wrecking ball (do they make them that big?), then the 1.2 mile asteroid would be a mustard seed. Is that right?

Ok. I've been too catastrophic.

But no matter whether 1 or 10 miles. Our little guest could wreak havoc on the entire planet.

I wouldn't want to be around even if it was 100 meters wide.

I'm curious, when these asteroids get within 2 LDs or less, does someone figure out where the Moon's orbit and the asteroid might cross paths?

I vaguely remember some monks or priests in a monastary who recorded what could have been a lunar impact that was visible from Earth in the 1800s or something. Anyone remember anything like that. I could have the date way off but I do remember it was some monastary type setting and these guys made a lot of records of their sky watching.

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It was June 18th, 1178 AD.
For more info, see here:
http://science.nasa.gov/headlines/y2001/ast26apr_1.htm

__________________
Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson

Well, I had the 18 in there so all those memory making cells aren't dead yet. That's a very interesting article. The fireball makes sense. I wonder if a Lunar impact would look much greyer due to distance and lack of atmosphere? That would add to the hypothesis of the event being an illusion effect.

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Democracy Now! - The lost art of investigative news reporting.

I don't know. They give a pretty good argument that it wasn't a lunar impact, but I can't quite accept the idea that it was a meteor. A meteor, even a fireball, would only last a couple of seconds. But from the description given by the witnesses I get the impression that the phenomenon lasted for quite a bit longer. It recurred a dozen times or moresounds like more thn a couple of seconds.

Also, even though the evidence is strong, I don't think it completely eliminates the lunar impact theory. I'm not completely convinced that there would have been such a large meteor shower after such an impact, or that it necessarily would have been recorded in history. Perhaps there was something about the impact that kept it from sending out much debris that could reach the Earth. Perhaps the meteor showers were much shorter and not the week or more that he thinks they should have been. And I think it's possible (though admittedly unlikely) for a big event to come and go without getting recorded in history.

I'm no physicist though, so I can't personally refute his claims. He may be completely correct.

So I think that even though there is good evidence that the lunar impact interpretation may be wrong, I think it's far from conclusive. The idea that it was a meteor also seems far-fetched.

__________________
...And that, my liege, is how we know the Earth to be banana-shaped. --Sir Bedevere

That article says "'I calculate that this would cause a week-long meteor storm comparable to the peak of the 1966 Leonids,' he said. Ten million tons of rock showering the entire Earth as pieces of ejecta about a centimeter across (inch-sized fragments) for a week is equivalent to 50,000 meteors each hour."

"Yet no vigilant 12th century sky watcher reported such a storm."

Are there any ancient accounts of meteor storms? How were they interpretted? Showers of frogs?

That's an interesting question. Our limited history books usually leave out astronomers from China and the Middle East. One hears the account of scientists dismissing rocks from space until much later than the 12th century. But there is that meteorite in Mecca that is worshipped because it is a rock from space that they believed was a rock from god. Hmmmm. I think I'll look into this.

Jefferson dismissed accounts of rocks falling from space--but meteors weren't known to be rocks, and the phenomenon was very well known of course. Surely showers were a common occurrence, then as now.

The Planetary Society has a pretty good synopsis of the debate:

http://www.planetary.org/html/news/a...8noimpact.html

In the reader response section, one person made an interesting comment likening the impact to that of Shoemaker-Levy 9 on Jupiter. In the original account, the monks reported seeing repeated flashes.



Withers' paper can be found here:

http://www.lpl.arizona.edu/~withers/...sbruno2001.pdf


He seems to focus almost exclusively on the hypothetical meteor storm. Curiously, he glosses over the evidence of the Moon's libration. He mentions that "turbulent core-mantle friction" could account for the wobble, but doesn't bother to go into detail.


Couldn't find anything on historical records...

Hmm, after reading the more complete witness statement on the http://www.planetary.org/html/news/a...8noimpact.html page, it's like there are two contradictory phenomena happening here. Let's go through it a line at a time:

Now there was a bright new moon...its horns were tilted toward the east; and suddenly the upper horn split in two. From the midpoint of the division a flaming torch sprang up, spewing out, over a considerable distance, fire, hot coals, and sparks.

This sounds most like an impact on the Moon, which would probably cause a large pillar of fire. I suppose a meteor at just the right angle could look like that, but I don't think they would describe it in such a manner.

Meanwhile the body of the moon which was below writhed, as it were, in anxiety...the moon throbbed like a wounded snake.

This seems more like an atmospheric effect. I doubt even a major impact would create movements in the Moon that would be visible from the Earth. This sounds more like seeing the Moon through turbulent air.

Afterwards it resumed its proper state. This phenomenon was repeated a dozen times or more, the flame assuming various twisting shapes at random...

It all went away, and then the flames returned again and again. That's not consistant with a meteor burning up in front of the Moon. That would have been only a single instance. Turbulence could come and go, but this says the flames came and went, and hung about changing shape, which wouldn't be atmospheric.

Then after these transformations the moon from horn to horn...took on a blackish appearance.

Once again an atmospheric effect is implied. I can't think of anything that could temporarily turn the whole Moon blackish, so it had to be something local.

So, what a confusing report. We have some comments that suggest a lunar impact, and others that suggest something in the atmosphere. I think the weight of evidence leans towards an atmospheric cause, the turbulent movement and blackish appearance could not arise from the surface of the Moon itself. Whereas it is possible to at least partially explain the flaming torch aspect of it with a meteor in the line of sight.

However, I've thought of another possibility. Whether it was a lunar impact or a fireball, if it was bright enough, it might create dark after-images in the eyes of the observers, which could be interpreted as the Moon writhing and turning dark. That might explain some of the observations. Just a thought.

__________________
...And that, my liege, is how we know the Earth to be banana-shaped. --Sir Bedevere