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Siberia
SFN Addict

Brazil
2322 Posts

Posted - 12/20/2005 :  04:32:52   [Permalink]  Show Profile  Visit Siberia's Homepage  Send Siberia an AOL message  Send Siberia a Yahoo! Message Send Siberia a Private Message
quote:
Originally posted by filthy

I've forgotten who said it but: "WWW-3 will be fought with nuclear weapons; WW-4 will be fought with sticks and stones." Seems reasonable.


Einstein did.

"Why are you afraid of something you're not even sure exists?"
- The Kovenant, Via Negativa

"People who don't like their beliefs being laughed at shouldn't have such funny beliefs."
-- unknown
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ronnywhite
SFN Regular

501 Posts

Posted - 12/20/2005 :  05:47:40   [Permalink]  Show Profile Send ronnywhite a Private Message
I already cold-heartedly carpet bombed spacecadet's Bible Code stuff last night in the religion/porn thread, so I better get back to asteroids. Besides, RE post hijacking charges, my attorney advises me to plead guilty, and appeal to the forum moderator by blaming everyone else... I mean, uh, noting that some posts back, I had valiantly attempted to "keep things on track" by offering to bore everybody... I mean, uh, address spacecadet's asteroid-relevant suggestions with calculations, but nobody took me up on it. Geez, now y'all gonna' make this ole' spam-hound geezer put on his bifocals and blow the dust off his slide rule... kids these days. Nevertheless, I'll try a few asteroid calculations tonight and post them as partial atonement for my utterly rude and inexcusable role in the hijacking conspiracy.

Ron White
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filthy
SFN Die Hard

USA
14408 Posts

Posted - 12/20/2005 :  06:08:17   [Permalink]  Show Profile Send filthy a Private Message
I was thinking that it might have been Einstein, but couldn't remember. Thanks, Siberia.

Hijacked threads are the most fun. Let's do another, soonest!


"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)

"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres


"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude

Brother Boot Knife of Warm Humanitarianism,

and Crypto-Communist!

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Dr. Mabuse
Septic Fiend

Sweden
9672 Posts

Posted - 12/20/2005 :  13:49:18   [Permalink]  Show Profile  Send Dr. Mabuse an ICQ Message Send Dr. Mabuse a Private Message
quote:
Originally posted by filthy

I was thinking that it might have been Einstein, but couldn't remember. Thanks, Siberia.

Hijacked threads are the most fun. Let's do another, soonest!



Actually, this may be a misquote. I've read somewhere that it's falsely attributed to Einstein, (and that the weapons of WW3 would be uncertain, but 4th would be sticks and stones).
I don't have time now to research the quote, I'll get back on that.

Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
Dr. Mabuse whisper.mp3

"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse

Support American Troops in Iraq:
Send them unarmed civilians for target practice..
Collateralmurder.
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filthy
SFN Die Hard

USA
14408 Posts

Posted - 12/20/2005 :  16:32:11   [Permalink]  Show Profile Send filthy a Private Message
quote:
Originally posted by Dr. Mabuse

quote:
Originally posted by filthy

I was thinking that it might have been Einstein, but couldn't remember. Thanks, Siberia.

Hijacked threads are the most fun. Let's do another, soonest!



Actually, this may be a misquote. I've read somewhere that it's falsely attributed to Einstein, (and that the weapons of WW3 would be uncertain, but 4th would be sticks and stones).
I don't have time now to research the quote, I'll get back on that.


Well, if it wasn't Einstein, that's ok. Almost everything else he said was worth listening to. And he played a better than decent violin; what more could be asked of a mere mortal?


"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)

"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres


"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude

Brother Boot Knife of Warm Humanitarianism,

and Crypto-Communist!

Edited by - filthy on 12/20/2005 16:34:41
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Dr. Mabuse
Septic Fiend

Sweden
9672 Posts

Posted - 12/20/2005 :  16:40:49   [Permalink]  Show Profile  Send Dr. Mabuse an ICQ Message Send Dr. Mabuse a Private Message
Some claim it might be George Orwell.
I haven't found anything to back that up, so I guess, in lack of evidence I'll have to concede.

Dr. Mabuse - "When the going gets tough, the tough get Duct-tape..."
Dr. Mabuse whisper.mp3

"Equivocation is not just a job, for a creationist it's a way of life..." Dr. Mabuse

Support American Troops in Iraq:
Send them unarmed civilians for target practice..
Collateralmurder.
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ronnywhite
SFN Regular

501 Posts

Posted - 12/22/2005 :  03:17:56   [Permalink]  Show Profile Send ronnywhite a Private Message
Meant to finish this yesterday, had to travel, just got home at Midnight so here it is (promised as restitution for post hijacking.) I will attempt to address the current issue- "Would a near-miss by Apophis, or Ann Coulter standing near a major faultline when infuriated by a liberal, be more likely to cause an earthquake?"

Disclaimer- numbers and a little guesstimation-syle math with explanations follow, so if you think your blood sugar's getting low, by all means ignore the rest of this post, else risk being bored into a coma.

Questions and Answers
1. What's a near-miss?
2. How long will Apophis be nearby?
3. Why will the path be pretty straight during that time?
4. I'm falling asleep... will you hurry up and get to the damn earthquakes?
5. So does Ann Coulter win, or does the asteroid win?
6. Why might an impact not be as bad as it sounds?


Aside from a few common, garden-variety formulas (e.g. F=ma) and constants (e.g. Pi) I'll just need a few less-common figures from the original link, and a couple of other relevant links...

Apophis Radius 0.1950 km
Apophis Mass 3.3e9 kg
Apophis Velocity 10 km/sec
Apophis "Window" Size "600 meter patch" (360000 m^2 I assume)
Probability of Earth Impact 1 in 5,500 or 1.82e-4
Earth Radius 6371 km
Earth Mass 5.974e24 kg
Earth to Moon Distance 60 Earth Radii = 3.8e5 km
Universal Gravitational Constant 6.67e-11 Nm^2/kg^2 = 6.67e-17 Nkm^2/kg^2
Continental Crust Area 29% of Earth Surface Area
Mean Continental Crust Density 2.7g/cm^3 = 2.7e3 kg/m^3 = 2.7e12 kg/km^3
Mean Continental Crust Depth 40 km


1. What's a near-miss?

According to the link, the estimated probability of Apophis impacting Earth, meaning it will pass through a "600 meter patch" of space at some point in time (I assume that means a 360000 m^2 area, or a circle about 367 meters in radius) is 1 in 5,500 or 1.82e-4… how is one to interpret this? My quick take is this... that means within this window, the vertex of the circle defining this area being a "bull's eye" hit on Earth, and the outer edge a peripheral glance, between there-and-here the gravitational forces will diverge the Apophis path one Earth Radii (6,471,000 meters) over 367 meters (0.347 km) of radial deviation within the circular "Window". There's a little more to it than this, but as a quickie guesstimation method, the forces acting on Apophis will cause distance deviation from Earth proportionate to the square of the distance from the center of the "Window." Assuming the confidence level used in this determination (I'd guess 95%, but it could well be 86% or 99%) that means that the hit probability of 1 in 5,500 is based on an almost certainty of Apophis passing through a window of area 5500 times the cross-sectional area of the Earth, or 5500 *Pi * (6731 km)^2 = 5500 * 1.4e8 k^2 = 7.7e12 km^2, or within a radius of sqrt((7.7e12 km^2)/Pi) = 2.8e6 km. That's (2.8e6 / 6.7e3) Earth radii or 4.2e2… about 420 Earth radii, as close as equipment allows measurement at this point... that's pretty close. So what's the best guess as to how close it likely will pass by? Maybe take the middle radius of the certainty "Window" and extrapolate out (that's a "safe" way to guess.) The edges of the Window translate to 420/sqrt(2) Earth radii or 298 Earth radii (call it 300) at this end... which means the middle of the "Window" radius translates to 300 / sqrt(2) Earth radii at pass-time, or about 213 Earth radii... a little over 3 times the distance to the Moon (by celestial standards, a pass of 60 Earth radii between the center of the Earth and the center of Apophis- or roughly just within a lunar orbit- would be insanely close, so this is indeed a "pretty tight squeeze." We'll call it 200 Earth radii. The probability of it hitting the moon are miniscule, even compared to that of the asteroid hitting the Earth [estimated well under 0.1% accord

Ron White
Edited by - ronnywhite on 12/22/2005 04:44:14
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filthy
SFN Die Hard

USA
14408 Posts

Posted - 12/22/2005 :  06:50:08   [Permalink]  Show Profile Send filthy a Private Message
Thanks Ron. I don't have the math to follow it exactly, but it's an interesting and most likely an accurate take on it. Would not a sea impact have serious and lasting effects on the global weather?

I do have the math to calculate Coulters impact -- everybody has those numbers. They total out to: Goose Egg. She couldn't cause an earthquake even if she jumped up and down, and laid a giant bean fart over the San Andras Fault. And I am of the opinion that her ass is the most powerful part of her. After all, she speaks out it constantly.


"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)

"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres


"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude

Brother Boot Knife of Warm Humanitarianism,

and Crypto-Communist!

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ronnywhite
SFN Regular

501 Posts

Posted - 12/22/2005 :  09:20:09   [Permalink]  Show Profile Send ronnywhite a Private Message
RE effects on weather with an ocean impact, my understanding is that the weather pattern changes they really worry about are from solid particulates dispersing into the atmosphere (same with "nuclear winter" scenarios, but the source is mostly smoke from burning debris in that case.) I'm sure there'd be some big waves and such... it's not like it would be on "page 3" of the newspapers, and anyone within a few hundred miles of impact would definitely be in for a bad day, but beyond the obvious, I'm clueless.

RE Ann Coulter, I forgot to factor in that in 30 years her ass will probably lose steam, but that's by no means a certainty. It might keep growing for all I know.

Ron White
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filthy
SFN Die Hard

USA
14408 Posts

Posted - 12/22/2005 :  10:02:43   [Permalink]  Show Profile Send filthy a Private Message
I was thinking that this thing would go in super-hot and release a vast quanity of steam into the atmosphere, possibly creating torrential rains and even hurricanes. I have not the least idea of how long any change would last.

I am begining to wonder if I have the right perspectice of the size of this thing. It ain't Pluto, after all.


"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)

"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres


"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude

Brother Boot Knife of Warm Humanitarianism,

and Crypto-Communist!

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ronnywhite
SFN Regular

501 Posts

Posted - 12/22/2005 :  22:17:53   [Permalink]  Show Profile Send ronnywhite a Private Message
No, it's not the size of Pluto, but still, fast as it's going it has a helluva lot of kinetic energy. And if the math seemed confusing, it's just because I couldn't explain it well enough without including pictures, and making the post 5 pages long. It's all very straightforward, really. If the last post wasn't clear to anyone, it's not because it's complicated- it's because of my lackluster explanation. Earlier I was thinking about the ocean impact/steam etc. question, and I'll try some more quick-and-dirty common-sense "guesstimative-style math" (again, with emphasis on "guess") to answer, and I'll try to make this more clear.

Question: How much cloudiness might result from an ocean impact?

I'll start with the mass and velocity of the asteroid to calculate the kinetic energy, since I can't immediately convert "100,000 Hiroshimas" into something even remotely manageable (i.e. my electric bills come in kilowatt-hours... not "micro-Hiroshimas" or something.) The asteroid has a velocity of 10km/s and a mass of 3.3e9 kg. Kinetic energy is 1/2*m*v^2 or 1/2 * (3.3e9 kg) * (10km/s)^2 = (1.65e17 kg*m / s^2) or 1.65e17 Joules (there... I feel much more comfortable with that than "megatons of TNT" or the like.) There are about 4.187 Joules per calorie, and a calorie is enough energy to raise the temperature of a gram of water 1 degree C. How gallons of water converted to steam are we talking about? Water has a density of 1 g/cc, 1cc = 1ml volume, so 1000cc of water = 1 liter, and there are 3.786 liters in a gallon or 3786 g. So it takes 3786 calories to raise the temperature of a gallon of water 1 degree C, or 3786*4.187 Joules = 15852 Joules. Also, it takes an extra 540 calories to vaporize 1 gram of water into steam at the transition temperature (100 C) or 2261 Joules, and thus it takes 2261 * 3786 = 85601 Joules to change a gallon of 100C water into steam. Let's call the percentage of energy converted to steam S (expressed as a decimal.) Say the oceanic temperature where it impacts is around T degrees Celcius... then converting S percent of the asteroid's energy to steam will vaporize G gallons of water, where

G = S * 1.65e11 / ( 15852 * ( 100 – T ) + 85601 ).

The mean (worldwide) oceanic temperature is 17C. As for the proportions of impact energy converted to steam, used to raise water temperatures, and cause wave turbulence and currents... I have no idea, so let's guess it's evenly divided. Then G = (1/3 * 1.65e17) / (15852 * 83 + 85601) = 39,000,000,000 or 3.9e10 gallons of water. As a point of comparison, a big cloud can contain 150,000 tons of water. That's 300,000,000 pounds. A gallon of water weighs about 8.3 pounds, so a big cloud might contain 3.6e7 gallons of water. 3.9e10 / 3.6e7 = 1.1e3.

Answer: If a third of the energy is converted to steam, it might make 1,100 big clouds.

What's that mean? Cancelled picnics, but beyond that, I have no idea. But a few other passing thoughts are...

An asteroid impact is actually much nicer than a huge nuclear detonation, because all of the expended energy begins as mechanical and ends up mostly as mechanical and thermal, whereas because the rate of energy release (impulse, or instantaneous power) is so massive, a portion will induce chemical changes... whereas a nuclear explosion gives off a significant part of the energy as electromagnetic and other ionizing high-energy particles causing radionucleotides and other extreme nastiness. Water is great stuff for absorbing/transferring thermal energy because it has a much better heat capacity than earth or rocks (that's why the coastal waters are warmer than deeper waters)... another reason ocean impact would be our best bet. Depending on the trajectory, if they screw-up attempts to deflect Apophis away from the Earth altogether, maybe a last-ditch effort might include directing it into deep mid-ocean waters. There'd be steam. The remaining energy would be expended as incre

Ron White
Edited by - ronnywhite on 12/23/2005 02:51:26
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filthy
SFN Die Hard

USA
14408 Posts

Posted - 12/23/2005 :  03:32:01   [Permalink]  Show Profile Send filthy a Private Message
Thanks Ron. I think I understand it a little better, now.

The question(s) now is: how do we deflect it and at what point in it's approcah do we make the attempt?

A further question might be: are there any more that present a tangeble threat, that have not been discovered.


"What luck for rulers that men do not think." -- Adolf Hitler (1889 - 1945)

"If only we could impeach on the basis of criminal stupidity, 90% of the Rethuglicans and half of the Democrats would be thrown out of office." ~~ P.Z. Myres


"The default position of human nature is to punch the other guy in the face and take his stuff." ~~ Dude

Brother Boot Knife of Warm Humanitarianism,

and Crypto-Communist!

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ronnywhite
SFN Regular

501 Posts

Posted - 12/23/2005 :  05:25:57   [Permalink]  Show Profile Send ronnywhite a Private Message
The farther away in time and distance an adjustment is made, the less energy is required to change the direction to a given point (again, the rule-of-thumb, common-sense guestimate dictates the energy required diminishes proportionately to the inverse-square of time/distance (either/or in the case of asteroids.)

As for major hit probabilities, it seems like we've gone quite a while without much ado, but then again, those in-the-know would have a better idea of how much sweating is justified. In the link they mentioned "nuclear propulsion" (I'm not sure exactly what they mean) but if they're talking about nuclear detonations, I've read that some scientists have proposed experimenting with small near-Earth asteroids and conventional explosives to gain a better understanding of the science and possible techniques to accomplish this in recent decades, while others have opposed the idea out of fear it might lead a tyrant with the resources to use the technology to attempt directing an asteroid at an enemy state, for instance.

I like trying this kind of guesstimation sometimes, but to put things in perspective, that's all it is... I'm not a PhD or even an amateur astronomer/meteorologist regarding the former/latter posts, and to do these things rigorously, as science should be done (to really "sweat the details") takes a lot of information, time, and computing power. So it's all just a fun exercise in skepticism to be "taken with a grain of salt." There are people on this website far more knowledeable in these areas than I who surely could comment more intelligently on this stuff (I couldn't point out and name a single star or planet, or even immediately recall the types of clouds... I just remember pilots call slamming an aircraft into a mountain running into a "cumulo granite cloud") but it's not a professional journal or the like, so "what the hell."

Regarding this "guesstimation" as it applied to the "Ann Coulter/Apophis" and "Cloudiness" calculations, and any others I make, my idea is not to bring any more arcane/obscure math or physics into the post than essential, and to attempt making the posts understandable, while keeping them down to a "sane" length. As I mentioned, I know there's a little more to it than I went into, and quite possibly much more than I'm aware of... take the translating a "600 meter window" and a probability to Earth-pass distances stuff. In reality, the transformed pass distances aren't evenly distributed throughout the window... it depends on where the window is located in space, and how close Apophis will pass to massive bodies enroute towards Earth (e.g. in some cases, given their short orbital periods relative to the present 30-year timeframe, depending on the direction Apophis approaches from, one just can't guess about these things).

Given minimal information, I think mine's just as good of a 50-cent-guess "off the street" as any other, but I don't discount the possibility an astronomer would say "it's bullshit." Even for me to really try and "do it right" I would need details about the Apophis ephemeris, possibly beginning with a nightmarish attempt to least-square fit NASA SpaceTrack data (assuming they'd even give it to me) surely including all kinds of weird parameters like solar radiation, sunspot activity, gravitation perturbations from Earth and other planets etc. etc. with my modest laptop computer, using vector fields, tensors, numerical analysis, which would take me months, the post would be a mile long... and I'm not an astronomer or astrophysicist to start with, so there'd be no guarantees about how accurate the result would be (and few on a skeptic website want to see that kind of stuff anyway.) The post turned out longer than I wanted it to, as it was.

I wouldn't bank on this stuff... it's fun, though.

Ron White
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vrwc
New Member

47 Posts

Posted - 12/23/2005 :  16:39:46   [Permalink]  Show Profile Send vrwc a Private Message
Wow! I looked on this to see if I had to build a bigger cellar (I couldn't afford a bomb shelter when JFK was waffling us into near war in the 60s) and I stumble on an NRA meeting with unsuspected members. Actually, some damn good advise on firearms and Ronnywhite (I suspect) has prematurely given up on his abliity to learn better shooting skills. As Filthy pointed out we all have a little shake in the hands. There are techniques to work around this problem. If an inveterate boozer can still hit beercans with a 9mm at 100 yards then a good scattergunner can match it, I'm sure. The advice on getting up to speed with a .22 hand cranker is a good way to train yourself. I still have the old Model 2 Winchester that my dad trained me to shoot when I was 7 years old. The ammo is cheap, so relearning is painless.

Maybe the trend toward 9mm handguns was overrated but they did have compactness with decent hitting power. I can't help but empathize with the bigger bore proponents, however. I'm afraid we lost some good men with the early M16s fouling problems that the M14 didn't have. Sure,you're packing slightly fewer rounds but your piece is always reliable and the old NATO round was probably a better man stopper than 4or5 M16 rounds. My oldest son was army in the cold war and I tried to persuade him to finagle a 14.By then the 16 was well refined and his unit had zero problems with it.

Speaking of reliable, there was earlier mention of the 1911 cal. 45. Arguably still the best manstopper of any handgun. Another of my sons is a big .45ACP buff, but the ammo is a bit pricey in these parts. Let me call your attention to the new Kahr P45, an amazingly compact "mini .45". The piece has a write up in the Jan. 06 American Rifleman. Kahr is mfg. in Worcester, MA, a state with "worst in the nation" firearms laws and a left-wing Attorney General who has promulgated "firearms safety" regulations which keep most major U.S.mfg handguns from being sold in the state. It takes some balls to mfg handguns in MA. I believe the website is Kahr Arms. com. Last I looked they didn't have the P45 up yet. vrwc
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ronnywhite
SFN Regular

501 Posts

Posted - 12/23/2005 :  22:20:14   [Permalink]  Show Profile Send ronnywhite a Private Message
vwrc
Hitting a beer can with a pistol at 100 yards is pretty damn good in my book… based on the last time I shot a pistol (maybe 20 years ago) I might be able to hit one at 10 yards (with a few tries, maybe) since I doubt my shooting skills have improved with age like "fine wine"... more likely they're now "fine vinegar" so I would likely better prefer a shotgun if a crazed band of maniacs were rushing my apartment, else if I had time to get to my car, maybe safer to just run them over. RE the M16... I read that when NATO switched to that smaller round, Moscow asked Kalishnikov whether they should similarly adapt the AK47, and he told them "No"... that there was no reason for such, but they insisted anyway, the result being the "Kalishnikov assault rifle" (a political decision, made against Kalishnikov's advice.) My understanding is that the original-version AK47 with the larger round is still the popular choice worldwide.

For lack of any bomb shelter at all myself, I'll try to better address the issue filthy raised regarding...

Question- "How big of an explosion will it take- and how far away, and when might it be detonated- to deflect Apophis away from Earth if it heads straight at us?"

I'll try to get a feel for it real "quick-and-easy like" using a few of the numbers calculated in the "Ann Coulter" and "Ocean Impact" posts, and a little more guesstimation and arithmetic. Assume it's heading for dead-center Earth. The asteroid is only 390 meters wide, and it's traveling at 10km/sec... a bomb would need to be placed at a distance directly alongside the point on Apophis path (P) where a "sideways shove" will divert it (at least several Earth Radii) laterally at the projected time of Earth arrival. One problem... doing this while it's still far enough away that Earth's gravity won't substantially converge the path back inwards. Another problem… the bomb has to be detonated at a precise instance to deliver the energy uniformly along the side cross-section of the asteroid, and placed so that the asteroid passes very close at detonation time. If the asteroid isn't spherical and is rotating, that could make placement and timing a little harder yet, but we'll assume it's spherical. Without going into the math, there's a circle of radius about 20 meters projected onto the center of the asteroid, along-side and within which the bomb has to be precisely placed, and detonated so that the energy from the bomb will strike the asteroid uniformly... since the effective energy delivered decreases with the cube of the distance, it's desirable to place the bomb close to the asteroid path (although at a greater distance, the boundary of the propagating energy field is "flatter" which has an advantage, but the tradeoff- more distance requires a more powerful bomb.) So the question of how long the detonation window might last could be estimated as ( 40 / 10000 ) or within 4 milliseconds, and if the bomb placement error is 10 meters, the window reduces to under 2 milliseconds. The error bounds can be widened by using a bomb with more energy, and assuming a bomb can be placed relative to the asteroid path and detonated at a point in time with adequate precision, a distance/energy calculation can be considered.
First, what will the angle of deflection need to be, and how far away? Suppose we plan trip-time for the device at 3 years with a mean space velocity of 36,000 km / hour or 10 km / s... the same speed as the asteroid. That would give us a distance of 3 * 10 * 24 * 3600 * 365 / 6371 = 148498 Earth Radii... we'll call our maximum travel distance 148,000 Earth radii. Consider an angle of deflection by "aiming for" a closest-point 10000 Earth radii adjacent to Earth. From the "Ann Coulter" post, at a distance of 200 Earth radii (point A) mutual gravitational forces accelerated the asteroid at 0.003m/sec^2 = 3e-3m/sec^2. So, the asteroids radial acceleration at this point would be 3e-3*(200/10000)^2 = 1.2e-6 m/sec^2.

Because the asteroid is moving at the same velocity as our mean trip speed, and it took us 3 years to get to this point, it will take the asteroid that long to get to Earth… or about 9.5e7 seconds to travel 148000 Earth radii. At the point of minimum distance from Earth the mutual gravitational acceleration will be maximized, so the distance the asteroid will be pulled back towards the Earth if we deflect it with this trajectory will be less than 1/2 * a * t^2 = 0.5* 1.2e-6 * (9.5e7)^2 = 5.4e9m = 5.4e6km = 8476 Earth radii... giving us plenty of room for error. The necessary deflection angle (call it Theta) will be arcsin(10000/148000) = 0.0676 radians or about 3.87 degrees. The kinetic energy necessary to deflect the asteroid by this angle will be (kinetic energy of the asteroid) * sin(Theta) = (10000/148000) * 2,500 = 2500/14.8 = 169 Megatons of TNT... a large nuclear bomb... but the problem is only the energy hitting the cross-sectional area will be useful. Suppose we position the device 195 meters, or a radius from the asteroid- the bomb will still need about 6 times the required energy to be effective. So a good size to use might be 1000 Megatons... that's pretty big, but it's doable. Because I over-maximized the miss-distance calculations, this would provide some elbow-room for error.

Guesstimate Answer- If we wait until the asteroid is 6 years away to launch a rocket, that will put it almost 150,000 Earth Radii away when we can redirect it at mid-point... 3 years from Earth. If we wait that long to act, we could position a thermonuclear device of at least 1000 megaton yield about 200 meters away with a distance-error window of 10 meters, and detonate it within a 2 millisecond time-error window. This should cause an (safely adequate) asteroid path deflection of about 4 degrees.

Note- Christmas Eve now... just got out of an insane zoo mislabeled as WalMart, and thought I might add I just clicked calculator quick-like "do it right" out of curiosity to see how far it would really deviate, and it's under 2000 Earth radii, so from that I'd guess far-less megatonage for a smaller angle would do the trick... maybe 100 or 2... but why not "play it safe" as long as we're spending all that cash on the plane ticket anyway... maybe might as well buy a double-seat and send a real big one. Besides, I think the tough part would be the positioning... fast as Apophis and the rocket would be approaching each other. Other thought- with 1000 megaton at 200 meters distance, it might disintegrate or shatter the thing (but that's complete speculation... I don't know.) That's a lot of energy. In 50's before figured out how to make tiny thermonukes with layered design, just knew how to do it using giant apparatus... no need in later years, but at that point considered as Cold War deterrant making such a 1000 megaton device to float to Moscow by submarine, launch to altitude of 1 mile (somehow) which calculations said might have reduced all of Moscow to powder and killed everyone not in shelters for a radius of 100 miles. Such an animal might wipe out the asteroid altogether, but it's hard to guess at (more to it than that.) Anyway, onward to K-Mart for more insanity now.

Ron White
Edited by - ronnywhite on 12/24/2005 15:11:00
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