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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."
I'd rather not see it coming.
Do not try to read the dupe, thats impossible. Instead, only try to realize the truth
What truth?
There is no dupe
it could have taken out a satellite by chance
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when i moo u moo - just like that
Does anyone know if an asteroid of this size could make landfall if made of the proper materials. Such as nickle, lead or other make up?
"Capital punishment makes the state into a murderer. Imprisonment makes the state into a gay dungeon-master"
The diameter of the earth is about 8,000 miles, so take the globe on your desk (you have one, right?) and imagine an object a little less than 3 diameters away...
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
Here's something we know will come and that has a destructive potential far greater than anything in our arsenals. It would foster global cooperation since all nations are potential targets, and it wouldn't create an arms race. An asteroid shield seems like a better way to spend all those money that goes into missile shield defense.
End of the world chart in true scientific fashion - a website dedicated to tracking asteroid collision paths - a 'solution' euphamistically means 'striking the earth' http://www.hohmanntransfer.com/crt.htm#news
The only PT Boat Journal on the web: http://www.PT171.org
Speaking of asteroids... I've heard somewhere that the burning of objects that enter the atmosphere being caused by friction is a misconception. Instead, it's actually heating caused by the immense air pressure that's created when an object moves fast enough through air. Is this true?
Well, yeah, and there's also the fact that nobody uses radar to discover these things anyway. It's all done with mirrors - that is to say, optical telescopes.
The real Captain Avatar is a fictional character, so I suppose he doesn't mind if I impersonate him.
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.
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 atmosphere is not that thick really. There is atmosphere up to this height, but its density is minuscule at an altitude of say 100 km. If you would assume constant density, it would be safe to assume a thickness twice the altitude where pressure is half that at sea level. This equates to around 2*5km, since at 5km pressure is 0.5 atm, and 50% of the air mass is contained below this level.
This would increase the temperature rise 60-fold, an increase of 15K... which would probably not kill us all, but would have great impact on life.
On the positive side, much of the energy generated will be radiated into space (over half of all radiation produced is directed away from earth). As the whole process probably occurs at high temperature, much of the energy will be radiant.
Finally, the other half of the radiant energy will strike the ground, heating up soil and water, increasing the total amount of mass that absorbes the energy.
Pretty complex stuff ;)