PDA

View Full Version : Asteroid Too Close?



Chip
2002-Jan-07, 10:07 PM
First the CNN story (http://www.cnn.com/2002/TECH/space/01/07/killer.asteroid/index.html) for today.

Then go here for movies of 2001 YB5 (http://www.spaceweather.com/asteroids/2001yb5_movies.html).

It missed the Earth on Monday by "only two times the distance of the moon." - CNN 01/07/02

If it had hit the Earth -- "The impact would be quite tremendous. It could essentially wipe out a medium-sized country." - Benny Peiser, Royal Astronomical Society, Great Britain.

Also see NASA website SpaceWeather.com (http://www.spaceweather.com/) for more information. It was visible at 12th magnitude.

Did anyone who posts here spot it? /phpBB/images/smiles/icon_eek.gif

Azpod
2002-Jan-08, 02:02 AM
On 2002-01-07 17:07, Chip wrote:
First the CNN story (http://www.cnn.com/2002/TECH/space/01/07/killer.asteroid/index.html) for today.

Then go here for movies of 2001 YB5 (http://www.spaceweather.com/asteroids/2001yb5_movies.html).

It missed the Earth on Monday by "only two times the distance of the moon." - CNN 01/07/02

If it had hit the Earth -- "The impact would be quite tremendous. It could essentially wipe out a medium-sized country." - Benny Peiser, Royal Astronomical Society, Great Britain.

Also see NASA website SpaceWeather.com (http://www.spaceweather.com/) for more information. It was visible at 12th magnitude.

Did anyone who posts here spot it? /phpBB/images/smiles/icon_eek.gif



??? Could an asteroid 300-400m in diameter actually destroy a country the size of France?! I would assume the impact would be tremendous, but wasn't the huge crater in Arizona created by an asteroid about that size? While the effects of the impact could certainly cover a country the size of France, I find it hard to believe that it could actually destroy it.

Does anyone have any information on this...?

Kaptain K
2002-Jan-08, 06:48 AM
??? Could an asteroid 300-400m in diameter actually destroy a country the size of France?! I would assume the impact would be tremendous, but wasn't the huge crater in Arizona created by an asteroid about that size? While the effects of the impact could certainly cover a country the size of France, I find it hard to believe that it could actually destroy it.

Does anyone have any information on this...?
The object that impacted in Arizona was on the order of 30-40m. A factor of ten smaller in diamete(1000 in mass). Yes, a rock that size could do considerable damage. /phpBB/images/smiles/icon_wink.gif

aurorae
2002-Jan-08, 03:52 PM
On 2002-01-07 21:02, Azpod wrote:

??? Could an asteroid 300-400m in diameter actually destroy a country the size of France?! I would assume the impact would be tremendous, but wasn't the huge crater in Arizona created by an asteroid about that size? While the effects of the impact could certainly cover a country the size of France, I find it hard to believe that it could actually destroy it.

Does anyone have any information on this...?



Try this nifty asteroid crasher:
http://janus.astro.umd.edu/astro/impact.html

It's pretty useful, although I suppose it was intended for children.

Azpod
2002-Jan-08, 06:03 PM
On 2002-01-08 10:52, aurorae wrote:

Try this nifty asteroid crasher:
http://janus.astro.umd.edu/astro/impact.html

It's pretty useful, although I suppose it was intended for children.




Ouch... off by a factor of 10 for the impact crater in Arizona?! I guess that means it's time to visit that baby again. /phpBB/images/smiles/icon_smile.gif

Cool simulator... tried it with a 0.4km rocky asteroid at 20km/s onto land, and got an impact equivant to 1/3's of the world's nuclear weapons, a 5km wide crater and an 8.0 Earthquake.

That wouldn't destroy something the size of France, but that would likely kill anyone within 100km or so...

Thanks!

_________________
Lobster sticks to magnet. (http://www.solarisdx.net/features/1lm.html)
That is all.

--Azpod... Formerly known as James Justin

<font size=-1>[ Edit: cant spel ]</font>

<font size=-1>[ This Message was edited by: Azpod on 2002-01-08 13:06 ]</font>

The Curtmudgeon
2002-Jan-08, 06:54 PM
On 2002-01-08 10:52, aurorae wrote:
Try this nifty asteroid crasher:
http://janus.astro.umd.edu/astro/impact.html

Alright, a new HTML toy!!! /phpBB/images/smiles/icon_lol.gif I'm going to start throwing some rocks around!


It's pretty useful, although I suppose it was intended for children.

Hey, wait a second, what are you trying to say about me!? /phpBB/images/smiles/icon_smile.gif

The (let's play catch the asteroid) Curtmudgeon

EckJerome
2002-Jan-08, 09:16 PM
Cool simulator... tried it with a 0.4km rocky asteroid at 20km/s onto land, and got an impact equivant to 1/3's of the world's nuclear weapons,


Only 1/3, eh? Exactly how large do they think the world's nuclear arsenal is?

Does the BA have a standard formula for impact force of meteors/asteroids? I know he goes over this point fairly often...that is the equivalent impact force (in nuclear bombs) of asteroid/meteor impacts. In most cases, the impact force of the asteroid is underestimated by MILLIONS of magnitudes.

Forgive me for thinking that a .4-kilometer asteroid travelling at 20kph would have more impact force than that. I suspect that the program has seriously overestimated the potential of the world's nuclear arsenal.

Eric

The Bad Astronomer
2002-Jan-08, 09:39 PM
On 2002-01-08 16:16, EckJerome wrote:

Does the BA have a standard formula for impact force of meteors/asteroids?

Not really. I just convert the kinetic energy into explosive energy (1/2 mass * velcity^2). To be accurate you need an efficiency factor in there, but I don't know what it is. A lot of energy goes into heat, but some goes into vaprozing the impactor, moving around dirt and water, etc. Then you can convert that energy into megatons knowing that 1 Mt = 4 x 10^22 ergs.

Try this (http://www.badastronomy.com/bitesize/kaboom.html).

Azpod
2002-Jan-08, 11:29 PM
On 2002-01-08 16:39, The Bad Astronomer wrote:


On 2002-01-08 16:16, EckJerome wrote:

Does the BA have a standard formula for impact force of meteors/asteroids?

Not really. I just convert the kinetic energy into explosive energy (1/2 mass * velcity^2). To be accurate you need an efficiency factor in there, but I don't know what it is. A lot of energy goes into heat, but some goes into vaprozing the impactor, moving around dirt and water, etc. Then you can convert that energy into megatons knowing that 1 Mt = 4 x 10^22 ergs.

Try this (http://www.badastronomy.com/bitesize/kaboom.html).


OK... I tried both, and got the following results in MT for a 400 meter rock asteroid nailing the Earth at 20km/s:

Solar System Collisions site: 3811 MT (they listed all the world's nuclear weapons at 10000 MT)

BA Site: 26808 MT!!!

I wonder why there's such a large difference between the values. *shrug* If the BA's numbers are correct, I can easily see it laying a country the size of France to waste.

David Simmons
2002-Jan-09, 01:50 AM
On 2002-01-08 16:39, The Bad Astronomer wrote:


On 2002-01-08 16:16, EckJerome wrote:

Does the BA have a standard formula for impact force of meteors/asteroids?

Not really. I just convert the kinetic energy into explosive energy (1/2 mass * velcity^2). To be accurate you need an efficiency factor in there, but I don't know what it is. A lot of energy goes into heat, but some goes into vaprozing the impactor, moving around dirt and water, etc. Then you can convert that energy into megatons knowing that 1 Mt = 4 x 10^22 ergs.

Try this (http://www.badastronomy.com/bitesize/kaboom.html).


Are you sure you need an efficiency, or yield factor? After all, isn't all of the energy of the impactor delivered to the earth in some form?

One Day More
2004-May-31, 08:33 AM
I know this is only resuscitatiing this topic, but the mention of the Arizona crater by several people reminded me of a question-I don't want to clutter the boards with threads with a topic that will have a lifespan of a Dragonfly! [-X Anyway, my question is, what would happen if a meteroid from space hurtled, by coincidence, into the Arizonian crater? :-? Just wondering.

Kaptain K
2004-May-31, 10:24 AM
Depends on the size of the impactor.

Small one = Small crater inside the current one.

Big one = Bigger crater in place of current one.

Tom Mazanec
2004-May-31, 03:42 PM
In most cases, the impact force of the asteroid is underestimated by MILLIONS of magnitudes.

Isn't this a bit of hyperbole? Millions of powers of ten?

frogesque
2004-May-31, 09:58 PM
It's not just the size of the rock that's important but also it's composition (ice, rocky or metallic) as this would have a major influence on whether it brokeup before impact. A low level ~ 1km airburst would likely produce more collateral damage than a deep impact.

More importantly, the kinetic energy of the meteorite is proportional to it's mass and the square of it's velocity so a smaller rock travelling at a higher relative velocity to the Earth could easily do more damage if it survived burnup on entry

One Day More
2004-Jun-01, 07:02 AM
One other question-I forgot it and now have to do it in a new post :oops: Anyway, that question is, can a meteorite ricochet? What happens if it does? Whoops, two, but if the answer to the first is no, the other is irrelevant I guess. :)

Kaptain K
2004-Jun-01, 05:49 PM
...can a meteorite ricochet?
Off the atmosphere? Yes, definitely! I know of two instances of it being observed (well, inferred from observations).

JustAGuy
2004-Jun-01, 06:22 PM
In most cases, the impact force of the asteroid is underestimated by MILLIONS of magnitudes.

Isn't this a bit of hyperbole? Millions of powers of ten?
I'd hope so. Otherwise an impact of even a 1 gram asteroid could tear the planet apart, rip a massive hole in spacetime, and end the universe as we know it!

Jpax2003
2004-Jun-02, 08:02 AM
In most cases, the impact force of the asteroid is underestimated by MILLIONS of magnitudes.

Isn't this a bit of hyperbole? Millions of powers of ten?
I'd hope so. Otherwise an impact of even a 1 gram asteroid could tear the planet apart, rip a massive hole in spacetime, and end the universe as we know it!I hate it when that happens.