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Asteroid Flies Under the Radar, Literally
Posted by
samzenpus
on Wed Dec 22, 2004 07:50 PM
from the too-late-to-drill dept.
from the too-late-to-drill dept.
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."
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First post (Score:5, Insightful)
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 [nationalgeographic.com] 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 [esa.int] is studying the issue [cnn.com], and NASA's Deep Impact [nasa.gov] project is also working on it.
This is NOT reassuring ... (Score:5, Interesting)
Something more dedicated to this would make everyone feel better probably
Re:This is NOT reassuring ... (Score:5, Insightful)
Re:First post (Score:5, Informative)
Re:First post (Score:5, Funny)
Re:Tell that to Bikini Atoll... (Score:4, Insightful)
Re:Tell that to Bikini Atoll... (Score:5, Interesting)
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.
Hmm (Score:5, Funny)
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...
Well if I'm going to be obliterated by an asteroid (Score:4, Interesting)
Re:Well if I'm going to be obliterated by an aster (Score:5, Insightful)
No they couldn't (Score:4, Informative)
There is nothing else we could throw at an incoming asteroid. The simple reality is that if we humans spotted a big rock coming at us, even with a month or two to prepare for it, all we could really do is dig a shelter, store food away, and pray that it comes down on the OTHER side of the planet.
Everybody PANIC!!! (Score:4, Funny)
Oops? But does it matter? (Score:4, Insightful)
If an asteroid does head for us, will it matter if we see it coming or not? Or will the grandiose idea presented in "Armageddon" be employed (despite being cool as hell.)
Personally, i'd rather be blindsided by a sixteen-wheeler, than sit by and see it head towards me for hours/days/weeks.
Let's see (Score:4, Interesting)
Planet saving == funding drive (Score:5, Funny)
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!"
Re:Planet saving == funding drive (Score:4, Funny)
The Dinosaurs didn't fund their NASA, and look what happened to them.
Re:Planet saving == funding drive (Score:5, Funny)
Yay... (Score:5, Funny)
I'm not worried though.
I have my teeny triangular space ship, and I'll destroy it before it becomes a problem....
WARNING! (Score:5, Funny)
well known cosmic blind spot? (Score:4, Funny)
I've never heard of it, until today!
Near-misses unnoticed (Score:4, Funny)
I think the Slashdot effect is very similar...
submit a story, it gets rejected, and a server admin sleeps quietly through the night.
One day... Mr Beer-Powered Robot Man. Just keep that site running......
Literally (Score:5, Insightful)
Politician mocked for supporting asteroid research (Score:5, Interesting)
asteroid, meteor, meteoroid, meteorite (Score:5, Informative)
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.
Re:meh (Score:5, Informative)
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?