Posted on 02/15/2013 11:28:48 PM PST by 2ndDivisionVet
At a news conference Friday, NASA scientists said the object that exploded over Russia was a “tiny asteroid” that measured roughly 45 feet across, weighed about 10,000 tons and traveled about 40,000 mph.
The object vaporized roughly 15 miles above the surface of the Earth, causing a shock wave that triggered the global network of listening devices that was established to detect nuclear test explosions.
The force of the explosion measured between 300 and 500 kilotons, equivalent to a modern nuclear bomb, according to Bill Cooke, head of the Meteoroid Environment Office at NASA's Marshall Space Flight Center in Huntsville, Ala.
“When you hear about injuries, those are undoubtedly due to the events of the shock striking the city and causing walls to collapse and glass to fly, not due to fragments striking the ground,” Cooke said.
Scientists believe the object originated from the asteroid belt, a vast collection of debris orbiting between Mars and Jupiter that consists of leftover bits from the formation of the solar system. The asteroid probably traveled for a year before it burst into the atmosphere Friday. As yet, no fragments have been recovered, but experts believe the asteroid was rocky in nature, and not formed of dense iron and nickel...
(Excerpt) Read more at latimes.com ...
The Moon is in a synchronous orbit. We always see the same “face” of it, and never see the other side, which is much more heavily cratered.
That...is bizarre.
Does the whole meteor/ite/oid thing apply to comets, too, or just asteroids?
What is also getting missed in these definitions is that what NASA was trying to explain was where it came from in the solar system that was important, and this is not based upon size, but the velocity of the object.
Everything in the solar system is affected by gravity. The Earth has a gravity well. In order to escape that gravity well, objects have to be travelling at least 11.2 km/s. Which gives us a rule of thumb, if we measure an object to be travelling at less than that speed, it is either an Earth captured object, or a man made object. If it is faster than that, it came from outside the Earth's gravity well.
The sun's escape velocity is 617.5 km/s. Each planet has a different speed orbiting around the sun. The difference between an asteroid and a comet, for example, is that comets travel far faster than asteroids, and are in a higher orbit. They come from the edge of the solar system, barely inside the gravity well of the sun. Asteroids between Mars and Jupiter are orbiting at lower speeds.
By measuring the speed of the object, they calculate that it was an asteroid, one with a highly elliptical orbit which crossed Earth's orbit.
“So... It didn’t start “traveling” until a year ago?! It was motionless all the preceding time?”
I saw that too. Maybe it was on the no-fly list prior?
“I watched a documentary last night and some scientists from NASA were talking about a scenario just like this. They stated that even if one was coming that we saw there is nothing we could do about it.”
What’s more likely is that if it very large, we can watch its orbit and figure out when it is coming at us, like they one yesterday. As to planetary defense. He’s right, there’s nothing we can do, since we don’t take it seriously.
“Also, there is a stupid notion (given that a lot of these people are supposedly “scientists”), that blowing one up closer in results in an even worse rain of pieces upon us than if we leave it alone.”
Also, what causes larger waves, dropping a 10 pound rock into a shallow swimming pool, or dropping 160 1 ounce rocks.
When we’re talking an asteroid hitting an ocean (which is the most likely case), it’s no different.
Meteors are asteroids which enter the Earth’s atmosphere. Meteorites are the stones, usually metallic, which survive impact with the Earth.
Meteors are asteroids which enter the Earth’s atmosphere. Meteorites are the stones, usually metallic, which survive impact with the Earth.
Slight correction: Comet fragments can also cause meteors.
How fast do comets usually travel?
Dense enough to be an Obama voter?
I'll try and find it.
Assume a spherical rock. At r = 22.5’, V = 47,713 ft^cu, or about 1800 cu yds in round numbers.
Concrete density is around 2 tons per yard, so there is 3600 tons. So we’d need some rock significantly more dense that concrete.
By the way, I did the math on 10,000 tons at 40,000 mph, and that comes out to 346,000 tons of TNT worth of kinetic energy.
Find...."Tape ends here. Second segment of Bin Laden's visit shows up at the front of the tape."
Mentions soccer field not football...I guess that's kinda like a big duh...
I just woke up and had yet another sci-fi recall, this book was about what happened when a super dense material hit earth, it was only the size of a baseball but weighed thousands of tons, it actually penetrated through the earth completely yet its exit was similar to a bullet exit and basically created a giant volcano.
Space could have anything from frozen mush comets to the afore mentioned super dense collapsed star material.
We could be hit with solid iron objects.
Makes for the intriguing discussion of what all the nations on earth could do....mine the asteroid field and to also create a defense net to divert these rogue objects.
That's a highly variable question, and depends on from where you are measuring, but the asteroid Eros, between Mars and Jupiter, travels at 24.36 km/s, and Haley's comet, when it crossed Earth's orbit, was travelling at 64.37 km/s. Haley is one of the slower comets, since it has a lower orbit than most comets. It only goes as far from the sun as Neptune, where most comets are orbiting the sun from the Oort cloud, far beyond pluto. These will travel at about 160km/s when near the sun. There are a class of comets called the Jupiter family comets. Comet Shoemaker-Levy 9, which struck Jupiter years ago, was one of these. Their speeds would be close to Jupiter's.
I don't believe anyone has ever seen an object in the Oort cloud. They are too far away, and too dark to be seen. But the comets we can measure when they get close to us are travelling at less than the sun's escape velocity, (617.5km/s) so we know they are not coming from outside the solar system.
As orbiting bodies, comets are required to follow Kepler's laws of planetary motion, even if they aren't technically planets.
So if a comet was to hit Earth it would do a lot more damage than an asteroid due to its much greater speed?
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