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Asteroid Flies Under the Radar, Literally
mrn121 writes "Space.com is reporting that a 16-foot wide asteriod has passed the Earth in a phenomenally close call. The Asteroid, named 2004 YD5, passed just below the 22,300 mile range where geostationary satellites sit. What makes the incident most interesting is that the asteriod was not seen until after it passed the Earth, due to the well-known Cosmic Blind Spot caused by the Sun."
The asteroids that are large enough to do damage can be seen far away enough that the cosmic blind spot is irrelevant. The article mentions a 2.9 mile wide asteroid (which would quickly wipe out all life on the planet if it hit) which scientists have known about for years. It won't come anywhere close.
At the moment, we have no defense against a planet-killing asteroid, but the European Space Agency is studying the issue, and NASA's Deep Impact project is also working on it.
How am I supposed to fit a pithy, relevant quote into 120 characters?
Sounds like we need to send an exploratory force out towards the sun to find out who the bastards are! Maybe they're on venus or mercury or somethin.
Oh wait. We don't _have_ an exploratory force. Oh well, guess we'll just have to be sitting ducks.
Or hope this was just a freak coincidence.
Sounds like a plot for a new movie...
Four small groups of dedicated astronomers in Arizona and California, totaling fewer than the number of employees at an average fast-food restaurant and using mostly off-the-shelf equipment for their telescopes, have been mapping the heavens and steadily adding to the number of known near-Earth objects. The article from TIME is here
Something more dedicated to this would make everyone feel better probably
Church: "Give us your money and listen to us or you BURN IN HELL!"
DOE: "Give us your money etc or YOU'LL RUN OUT OF GAS!"
NASA: "Give us your money or YOU'LL GET KILLED BY AN ASTEROID!"
Engineering is the art of compromise.
Stealth Asteroids....
I'm not worried though.
I have my teeny triangular space ship, and I'll destroy it before it becomes a problem....
RoseColor red={0, 0xffff, 0x0000, 0x0000};VioletColour blue={0, 0x0000, 0x0000, 0xffff};find / -name *mybase*|chown you
Just to correct something...
Asteroid:
Any of numerous small celestial bodies that revolve around the sun, with orbits lying chiefly between Mars and Jupiter and characteristic diameters between a few and several hundred kilometers. Also called minor planet, planetoid.
I.E. still in space and orbiting.
Meteor:
A bright trail or streak that appears in the sky when a meteoroid is heated to incandescence by friction with the earth's atmosphere. Also called falling star, meteor burst, shooting star.
I.E. that which is shooting through the atmosphere, heating it and itself up in the process due to friction.
Meteoroid:
A solid body, moving in space, that is smaller than an asteroid and at least as large as a speck of dust.
I.E. still in space, not necessarily orbiting, smaller than an Asteroid. I think you meant this one.
Meteorite:
A stony or metallic mass of matter that has fallen to the earth's surface from outer space.
I.E. Fallen onto the Earth. It's what you may find if you're either lucky, or very observant.
So just to conclude.. this is indeed a Meteoroid, as it's not big enough to actually be an Asteroid. But it's more fun to say, and less confusing to the masses - especially the Nintendo owners out there.
Asteroids may be closer than they appear.
I've fallen off your lawn, and I can't get up.
Yeah. A couple years ago, I ran across an article that contained a graph of object size versus frequency of entering the Earth's atmosphere. The 1-per-day frequency was for objects of about 3 meters diameter.
;-)
Several objects of this thing's size enter our atmosphere each week. Most of them disintegrate in the atmostphere. A few have pieces that hit the ground, though they're usually rather small by the time they (or the pieces) hit.
To do serious damage, we'll need a rock at least a few hundred meters across. Of course, one of those may hit us next week. Or 10,000 years from now. (Or both.
I wonder if I could find that graph again?
Those who do study history are doomed to stand helplessly by while everyone else repeats it.
Wrong. We have have an accurate delivery system in the form of Clint Eastwood, Tommy Lee Jones, Donald Sutherland, and James Garner.
If we need a second chance, maybe they can get Lance Bass.
Someday a Slashdot ID of 177180 will mean something.
So... when you say 'literally', you mean 'metaphorically' right? As in not literally under a radar... *sigh*
It was back in maybe 1965/66? Dark night with no moon, playing an away game of jv football in Albemarle? NC.
That sucker arced across 20% of the sky with a really orange red tail and exploded. Almost looked like dawn was coming, I waited for sound, started counting off seconds to range it's distance, but no sound ever came.
Just for a moment I thought it was the Russians, but that's another story.
Something I will never forget.
And some asteroids come even closer, entering the atmosphere. Most never reach the ground because they break apart under the stress of entry. One study of data collected by U.S. military satellites logged 300 in-air asteroid explosions.
"Where did this apple come from?"
--Alan Turing
It's interesting to note that when Congressman Anthony Weiner (D-NY) tried to introduce a bill to provide additional funding for tracking near-earth asteroids, he was mocked by some of New York Mayor Michael Bloomberg's aides. In general, supporting things like this (even though they're actually pretty important) is a good way to get yourself targeted for "not caring about things here on Earth."
Well, let's run some numbers, shall we?
:-)
:-)
Warning! Gross oversimplifications and estimates follow!
For the purposes of this problem, we'll assume the ginormous million-year doomsday rock, a 1000-m diameter chunk of iron. A 1000-meter sphere of iron has a mass of 3.30 × 10^13 kilograms. At an impact speed of, say, 30 km/s (approximately Earth's speed of orbit around the sun), that rock has a total of (1/2) * (3.30×10^13 kg) * (3×10^4 m/s)^2 = 1.5 × 10^22 Joules of kinetic energy.
Now, let's make some assumptions about the atmosphere. We'll assume the atmosphere is of uniform density, distribution, and composition, and about 120km high (not a terrible approximation, but not a good one either). The volume of the atmosphere is then (4/3) * pi * ((6.498×10^6)^3 - (6.378×10^6)^3) = 6.25 × 10^19 m^3.
The density of air at sea level is approximately 1.29 kg/m^3, so the mass of our atmosphere is then (6.25×10^19 m^3) * (1.29kg/m^3) = 8.06 × 10^19 kg.
If we assume the volume remains constant, the specific heat of the atmosphere is 716 J/kg*K, so the introduction of 1.5 × 10^22 Joules of energy will result in a temperature increase of dT = E / (m*s) = (1.5 × 10^22) / (8.06 × 10^19 kg * 716 J/kg*K) = 0.26 K
So, in summary, a 1-km diameter asteroid made entirely of iron, travelling at 30km/s relative to the Earth, and assuming all the kinetic energy was converted to thermal energy and spread evenly across the entire globe, would raise worldwide temperature by less than half a degree celsius.
Now, if we assume a rock like the one supposed to have extinguished the dinosaurs, i.e., a 10-km rock, which consequently has 1000 times the mass, then the global temperature change could be as high as 260 degrees celsius, which is where things really start cooking.
If I made any slip-ups in my math, please point them out. It's entirely possible, since I didn't bother double-checking. Although I made so many liberal assumptions anyway that if you use these numbers for anything, you're crazy. This was more a diversion into the sort of problem you'd find in an elementary physics textbook than an actual scientific exercise.