Wow!

[Blue Monster 65]

Cool video here: http://blogs.usatoday.com/ondeadline/20 ... om-ou.html

Scott

[KLA2]

Wow! Could be that $100,000 toolkit coming home ...

[Blue Monster 65]

Bwahahahahahahahahahahahaha! You're absolutely right there, KLA2!

But in that case, would it be the "Jesus Asteroid?"

Scott

[Arneb]

And even that wouldn't match the rate at which the Space Shuttle program is burning cash.

[MM_Dandy]

Wow! Could be that $100,000 toolkit coming home ...

Presumably, USAF Space Command would have said so by now.

[Dragon Star]

I saw a fire ball one time when I was working night shift after I returned from Dallas, I was falling asleep on a picnic table at 3:30 AM in the courtyard of the High School, next thing I know SWOOOSH across the sky it went in a beautiful blue-green arc at amazing speed, crossed the sky in less than a second with a wonderful flash as it crossed the horizon. One of the coolest things I've ever seen.

[KLA2]

Meteorite pieces found in Saskatchewan

Fragments of a huge meteorite that lit up the skies across Alberta and Saskatchewan last week have been found near the border city of Lloydminster, University of Calgary scientists say.

U of C planetary scientist Dr. Alan Hildebrand and graduate student Ellen Milley said Friday morning they located several meteorite fragments late Thursday afternoon.

They believe thousands of meteorite bits are strewn over a 20-square-kilometre area near the Battle River.

They're planning to take reporters to the as-yet undisclosed site — about 40 kilometres from Lloydminister — Friday afternoon.

The fireball that streaked across western Canadian skies on Nov. 20 was witnessed by thousands. Researchers believe it was a 10-tonne fragment from an asteroid.

It was also captured on video by a number of people.

http://www.cbc.ca/canada/saskatchewan/s ... orite.html

I found this readers comment amusing:

"So a 10 tonne object enters our atmosphere and then our air space and crashes to earth in a ball of flames...and all this happens completely undetected?...until reported by people looking out their windows?
Good to see all that money we are funelling to NORAD to protect our air space is not being wasted! But all is not lost, I hear they are still able to track Santa Claus on Christmas Eve."

10 tonnes? That's pretty big. I assume it was more a "dirty snowball" than iron, or it would have made some big hole!

For anyone that wants to convert weight to volume, here is a site:

http://www.convert-me.com/en/convert/weight2volume

[KLA2]

I saw a fire ball one time when I was working night shift after I returned from Dallas, I was falling asleep on a picnic table at 3:30 AM in the courtyard of the High School, next thing I know SWOOOSH across the sky it went in a beautiful blue-green arc at amazing speed, crossed the sky in less than a second with a wonderful flash as it crossed the horizon. One of the coolest things I've ever seen.

Sounds way cool, DS. I have never observed such a thing.

As for the picnic table part ... "don't ask, don't tell."

[MM_Dandy]

10 tonnes? That's pretty big. I assume it was more a "dirty snowball" than iron, or it would have made some big hole!

I'm not so sure it's something we need to worry about so much; a 10-tonne solid iron meteorite would be something like a sphere with a 1.3 m diameter. Objects of that size hit the Earth's atmosphere on the order of once every 1 - 2 years, and never reach the ground intact.

While I was getting the info to do the calculations, I came across this Universe Today update. Which roughly agreed with my calculated size (it calls it desk-sized), but completely blew away my estimate of frequency.

...a fireball this size only occurs over Canada once every five years on average. About ten fireballs of this size occur somewhere over the Earth each year.

[KLA2]

I'm not so sure it's something we need to worry about so much; a 10-tonne solid iron meteorite would be something like a sphere with a 1.3 m diameter. Objects of that size hit the Earth's atmosphere on the order of once every 1 - 2 years, and never reach the ground intact.

Are you sure? I thought it was the little ones that were slowed by atmospheric resistance and did little damage on impact.

A ten tonne (that’s 22,046 pounds, 22 tons) solid iron meteorite that did not break up high in the atmosphere … assuming speed of 25,000 mph … that’s (F=MV) 550 kilotons of force? (Forgetting my high school physics) The meteorite or associated shockwave would have to do some damage, no?

Too lazy to research this, but there are others here who will know offhand. Probably you, MM Dandy. Just, I did not realize our atmosphere protected us that well from something that massive and dense. :?

ETA: Oh, crap. I just realized I converted wrong ... 22,046 lbs is 11 tons.
Therefore, presumably, only 275 kilotons. Never mind.

[Enzo]

And that is the mass before the atmosphere grinds the outer parts away?

[KLA2]

And that is the mass before the atmosphere grinds the outer parts away?

Well, as I understand it, if it does not break up upon contact with the atmosphere, the meteorite creates a shock wave in front of it. It is this shock wave of compressed air that becomes so hot and appears as a fiery trail. The actual meteorite itself does not burn, melt or even necessarily become heated through. (There are reports of meteorites picked up just after landing being cold to the touch.)

Solid iron, being ... well ... iron does not easily break up, and so the meteorite may hit the ground intact. If it is large enough, the atmosphere will not slow it down significantly and compresses in front of it, creating a shock wave over a fairly small area as damaging as the meteorite on impact.

But, I am out of my depth here. Anyone?

[Arneb]

There is plenty of energy to break up the projectile. We all remember Columbia, don't we? The meteorite we see on the Universe Today website is about the size of a small potato, while the original (exactly, Enzo, before entry) 10 ton impactor was, acording to Fraser, "as big as a desk".

The BA has a page on why must meteorites you will find are cold to the touch here. In short: The meteorite gets very hot during entry (most of them literally explode from heat and air resistance) , but a) most of the fragments are from the inside of the projectile, so they don't heat up that much, and b) they have a long way to fall through the atmosphere, which is very cold up high, so they have a long time to fall in a bit of a cold breeze and thus cool off.

[Enzo]

Hey Scott, there's a name for our band - Iron Potato



or maybe Space Potato

[Blue Monster 65]

We'll have to get Mactep as the front man and KLA2 as the Toaster.

Heh heh heh ... no Jamaican accent, but a heavy, heavy Canadian one, eh? "Yah! Get some riddim dere, eh?" :D

Scott

[troubleagain]

I can sing harmony. 8)

[Blue Monster 65]

ENZO
SAY
RELAX

MACTEP
SAY
OBEY



Scott

[troubleagain]

I'm really not very good at "obey"..... :?

[Blue Monster 65]

Must ... bite ... tongue ... avoid ... severe ... beating ...

Scott

[Enzo]

You.. like... beatings... remember?


Yah, dat's rockin' now, eh?

Obey, como va? by Sam Tanner

[troubleagain]

Must ... bite ... tongue ... avoid ... severe ... beating ...

Scott

Yes?

[Blue Monster 65]

Not like that, Mistress!

Heh heh heh ...

Scott

[KLA2]

We'll have to get Mactep as the front man and KLA2 as the Toaster.

Heh heh heh ... no Jamaican accent, but a heavy, heavy Canadian one, eh? "Yah! Get some riddim dere, eh?" :D

Scott

The Toaster?? Maybe, The Male Box. {thank you (?), Enzo.} Yeah {I mean, Right}, that's it. Chicks could shove $10 bills into my ... well. Oiled machinery.

Just as long as we don't play any gay bars.

In which case, Billy T. could stand in for me.

{OK, that WAS below the belt. Any due apologies rendered. :wink: }

[KLA2]

There is plenty of energy to break up the projectile. We all remember Columbia, don't we?

Come on, Arneb. A space shuttle* is more like an eggshell than a solid iron meteorite. (If there is such a thing)

If there is, I am not sure it would burn up, slow up, or break up much, on entry. If the latter, would the pieces not hit the ground with as much combined force as the whole?

* Even the Mercury/Gemini/Apollo capsules were more space than substance. They floated after landing. And were designed to burn off the resin based heat shield to slow down on reentry.

[Arneb]

My point was just that their is a lot of entry energy to heat the projectile and break it apart, hollow or not.