backtop

Print E-mail del.icio.us 124 comment(s) - last by LatinMessiah.. on Apr 18 at 6:27 PM
13-year-old says Apophis has 1 in 450 chance of hitting Earth in 2036

NASA predicted that the Apophis asteroid has about a 1 in 45,000 chance of hitting the Earth in 2029 when it will to pass by the Earth at a distance of around 32,500 kilometers. Apophis first became an object of attention in December 2004 when the asteroid was deemed to have a 2.7% chance of striking the Earth.

The fear is that the asteroid could pass through a gravitational keyhole leading to an impact with the Earth in 2036 when the asteroid makes another orbit near earth. According to NASA, if the asteroid struck the earth it would create a 1,049 foot wide ball of iron and iridium weighing 200 billion tons that would crash into the Atlantic Ocean.

The result of this crash would be devastating to the Earth as huge tsunami waves would be generated and obliterate coastal areas as well as inland areas. In addition to the Tsunami threat, the impact would create a thick dust cloud that could darken skies for an unknown period of time. The threat of impact from Apophis led to some calling on the UN to get a plan in place to deal with the threat asteroid impacts.

Yahoo News reports that a 13-year-old German schoolboy, Nico Marquardt, found a fault in NASA’s calculations. Marquardt used telescopic findings from the Institute of Astrophysics in Potsdam to calculate the likelihood that Apophis would collide with the Earth in 2036. The boy took into account the chance that Apophis could strike one of the 40,000 orbiting satellites around the Earth on it initial pass in 2029 leading to a change in the trajectory of the asteroid.

This change in trajectory if Apophis strikes a satellite could mean an impact in 2036. According to Marquardt the likelihood of Apophis striking the Earth in 2036 is 1 in 450, not the 1 in 45,000 NASA predicts.

Comments     Threshold


This article is over a month old, voting and posting comments is disabled
I'm ashamed
By phatboye on 4/16/2008 10:44:37 AM , Rating: 3
As a graduate with a B.S. in Math I wouldn't even know where to begin on how to do calculations like that. What the hell are they teaching these kids at his school and why wasn't I ever taught how to do something like that. I spent most of my undergraduate years in math learning about crap that would never be useful in the real world. Or is this kid just smart enough to have just figured out stats all by himself? w/o a very expensive education.




RE: I'm ashamed
By drakanious on 4/16/2008 10:50:49 AM , Rating: 2
I would assume some advanced differential equations and statistics?


RE: I'm ashamed
By masher2 (blog) on 4/16/2008 11:06:53 AM , Rating: 4
You can do pretty much everything you need in orbital mechanics with nothing but calculus. In fact, as the equations are already derived, I assume this kid simply plugged the values in same as NASA did...but added in the additional step of a probabilistic assumption of a small amount of velocity loss due to a collision with a geosynch satellite.


RE: I'm ashamed
By General Disturbance on 4/16/2008 11:29:35 AM , Rating: 4
It sounds to me like all the kid did was increase the cross-sectional interaction radius of the earth by including the orbit of geo-stationary satellites, and saying that if the asteroid passes within this radius it has the potential to strike a satellite which loosely could be classified as dangerous and an impact.
The calculation would simply be:

Earth_Only_Chance/Geo_Orbit_Chance = Earth_Radius^2/Geo_Radius^2

(1/45000)/Geo_Orbit_Chance = 5000km^2/(40000km)^2 = (~1/10)^2

Geo_Orbit_Chance = (1/45000)*(~10^2) ~ 1/450

This would be the level of a, what was it, 12 year old's math ability and education level.


RE: I'm ashamed
By EntreHoras on 4/16/2008 3:56:41 PM , Rating: 2
I felt like reading the script for "The Big Bang Theory" only without the hot blondie.


RE: I'm ashamed
By clovell on 4/16/2008 5:12:45 PM , Rating: 2
Exactly. With thousands of satellites and possible collision vectors and momentum transfer scenarios with said satelites, the equations that would have to be recalculated and re-computed - basing this number on the expected value of the conditional probabilities of possible trajectories following a satellite collision would bring the world's combined computing power to its knees.


RE: I'm ashamed
By TwistyKat on 4/16/2008 1:46:48 PM , Rating: 5
quote:
I assume this kid simply plugged the values in same as NASA did...but added in the additional step of a probabilistic assumption of a small amount of velocity loss due to a collision with a geosynch satellite.


Either that or NASA forgot to carry the 1.


RE: I'm ashamed
By Samus on 4/16/2008 2:25:46 PM , Rating: 2
They probably didn't account for the metric system...again. OPPS.


RE: I'm ashamed
By daInvincibleGama on 4/16/2008 6:06:23 PM , Rating: 4
NASA and the entire Us science community have been using the metric system for decades now.


RE: I'm ashamed
By daInvincibleGama on 4/16/2008 6:06:45 PM , Rating: 3
US*


RE: I'm ashamed
By rebturtle on 4/16/2008 10:13:20 PM , Rating: 3
I believe this is what most of us were thinking of:
http://www.space.com/news/070108_moon_metric.html

quote:
The dual strategy led to the loss of the Mars Climate Orbiter robotic probe in 1999; a contractor provided thruster firing data in English units while NASA was calculating in metric.


RE: I'm ashamed
By lompocus on 4/17/2008 7:32:22 PM , Rating: 1
He's 13 you retard!


RE: I'm ashamed
By Ammohunt on 4/17/2008 5:04:55 PM , Rating: 2
Try Trigonometry if you the OP would have joined the ARMY Artillery rather than waste his time on College indoctrination he would have learned the calculations necessary to predict such an impact.


RE: I'm ashamed
By cochy on 4/16/2008 10:50:59 AM , Rating: 5
Umm..Since this Yahoo! article provides absolutely no information about his calculations, this is what I'm assuming.

He simply figured the odds of the asteroid hitting one of the satellites (I didn't even know there were satellites orbiting at over 30,000km). He then equated a hit with changing the trajectory of the asteroid exactly enough to absolutely hit Earth.

This obviously can't be right as a 200 billion ton asteroid being stuck by a nuclear weapon would have a minimal effect on it's trajectory let alone it hitting a tiny pot hole in space (satellite).


RE: I'm ashamed
By NEOCortex on 4/16/2008 11:00:18 AM , Rating: 2
I to am a little skeptical about the influence a satellite would have on an asteroid of that size. One thing the source article mentions that this articles doesn't is the fact that NASA apparently agrees with this kid, so I guess there is validity in his calculations.

I just wish there were more details...


RE: I'm ashamed
By cochy on 4/16/2008 11:06:27 AM , Rating: 2
Well it says they both agree on what would happen if it hit. NASA didn't comment on his calculations.


RE: I'm ashamed
By headbox on 4/16/2008 12:06:19 PM , Rating: 2
NASA is probably still checking his math.

This article jumps out as B.S. because he would have to accurately calculate the new trajectory for each of the impacts. It seems like his calculations imply that contact with any other object in space would put it on course with Earth.


RE: I'm ashamed
By masher2 (blog) on 4/16/2008 12:20:13 PM , Rating: 2
> "This article jumps out as B.S. because he would have to accurately calculate the new trajectory for each of the impacts"

Well, the story *is* BS, but not for the reason above. You don't have to calculate new trajectories for each...just the increase in a keyhole capture scenario due to the loss of velocity from an impact.


RE: I'm ashamed
By Some1ne on 4/16/2008 3:52:41 PM , Rating: 2
The loss of velocity that occurs when a 200 billion ton object (is that really the right number? Seems a bit high) collides with a 10 ton object is about the same as the loss of velocity that occurs when a city bus collides with a fly. Which is to say, essentially 0.


RE: I'm ashamed
By masher2 (blog) on 4/16/2008 6:20:26 PM , Rating: 3
As calculated below, its sufficient to cause a dV sufficient to change the asteroid's path by one meter every 8 days or so...or by about 320 meters by the time the asteroid comes around again in 7 years.

Small indeed...but not zero.


RE: I'm ashamed
By erikejw on 4/16/2008 10:47:04 PM , Rating: 2
This makes sence and is a probablity.
Especially if the asteroid is very likely to overshoot the specific area any lower velocity will make it more likely to hit that "hole" in space.

The 100 times more likelyhood sounds too high though but what do I know I am just a physics Msc not a 12 year old kid ;)


RE: I'm ashamed
By Adonlude on 4/16/2008 1:04:37 PM , Rating: 2
In 20 some years if you suddenly find yourself atop a dirt bike rushin up the side of a mountian to escape the seas that are engulfing what was once dry land, I want you to look back on this moment.


RE: I'm ashamed
By Joz on 4/16/2008 9:37:49 PM , Rating: 2
dirt bike?

Im gona be rushing up in a 93 jeep grand cherokee with a more "modern" co-axial fission engine. and BIG ASS TIRES.

lol

yea.. I live in MN, tidal waves? plz.


RE: I'm ashamed
By ThisSpaceForRent on 4/16/2008 11:07:23 AM , Rating: 2
I believe satellites in a geo-synchronous orbit are at out that far. That would mean weather satellites, satellite tv, and basically anything that uses a dish on the ground that doesn't actively track a satellite (I believe).

The upside to this thing hitting Earth is that Iridium is worth like 400 USD per troy ounce last time I looked. =)


RE: I'm ashamed
By masher2 (blog) on 4/16/2008 11:18:09 AM , Rating: 2
Not quite. Most objects in geosynch orbit move relative to the ground (the Sirius radio satellite constellation is a prime example). It's the geostationary satellites that maintain a fixed position.

Moving objects don't necessarily need to be tracked...just put an omni antenna on and boost the signal strength a bit to compensate.

> "The upside to this thing hitting Earth is that Iridium is worth like 400 USD per troy ounce "

If this hits the earth, expect prices to drop fast!


RE: I'm ashamed
By MrTeal on 4/16/2008 11:35:41 AM , Rating: 3
Yeah, if this thing hits, forget speculating on Iridium. Corner the market on fresh water and diesel generators.


RE: I'm ashamed
By Adonlude on 4/16/2008 1:11:57 PM , Rating: 4
Pretty sure there are laws against profiteering on needed supplies during a crisis. In a SHTF situation if the law doesn't kick in then you can probably expect to get shot right before your supplies get taken.


RE: I'm ashamed
By lagomorpha on 4/16/2008 9:45:34 PM , Rating: 2
SHTF means stock up on ammunition. LOTS of ammunition.


RE: I'm ashamed
By therealnickdanger on 4/17/2008 8:13:35 AM , Rating: 2
Buy your property in Montana now and fortify it while you can!


RE: I'm ashamed
By cvmaas on 4/16/2008 12:58:16 PM , Rating: 3
Actually, thats not quite true. I'm an engineer with Sirius and we are working on putting up FM5 in a geostationary orbit, so we would have a hybrid constellation. The geo birds do move quite a bit, and require 2-4 maneuvers / day to maintain their orbit so that they stay stationary relative to the Earth. Their ground track is typically a small figure 8 on the equatorial horizon, but the payload antennas are wide angle so that they cover a very large land area and consequently dont need to be tracked by end users.

However, Telemetry, tracking and command is narrow angle and must be tracked. Ideally, we could boost the power output and use a cheaper stationary omni antenna, but in space you can't just come up with extra power.

Sirius's main constellation is highly elliptical inclined orbit centered at 96* W, but they move in a figure 8 from northern Canada all the way to the southern tip of South America, and consequently need a ground station in Panama and Equador to track the satellites when they are south of the equator.


RE: I'm ashamed
By masher2 (blog) on 4/16/2008 1:02:23 PM , Rating: 2
> "Actually, thats not quite true. I'm an engineer with Sirius and we are working on putting up FM5 in a geostationary orbit"

Sorry...I should have said your *current* constellation isn't geostationary. However, I didn't know FM5 wasn't going to be in an elliptical orbit. What's the rational for the hybrid constellation?


RE: I'm ashamed
By cvmaas on 4/16/2008 1:41:22 PM , Rating: 2
I did, just further in the post:

"Sirius's main constellation is highly elliptical inclined orbit centered at 96* W..."

I guess I should have stated thats not a geostationary orbit better.. Sorry about that.

Anyway, the idea of the hybrid constellation is to broadcast the payload on 2 different frequencies from 2 different orbits. So if your line-of-sight with one of the broadcasting satellites is blocked, we hope you will receive the signal from the other bird in a different orbit.

Geostationary birds are typically blocked by tall buildings and trees. Thats why DirectTV dishes need to be on a certain side of the house, with an unobstructed view, yadda yadda.

XM's birds are all geostationary, so they use a large network of on ground repeaters to broadcast to the areas their geo birds can't hit. Sirius doesn't use nearly as many ground repeaters.

Sirius on the other hand, currently has 3 birds in the HIEO orbit, 120* apart, with 2 broadcasting at any 1 time, when they are in their apogee loop, which is directly overhead on the continental US and CN. Since we are overhead, our signal isn't blocked by buildings, but rather by things like bridges and tunnels, where the Geo bird is better at broadcasting a signal into.


RE: I'm ashamed
By SecTech767 on 4/17/2008 9:34:09 AM , Rating: 2
quote:
He simply figured the odds of the asteroid hitting one of the satellites (I didn't even know there were satellites orbiting at over 30,000km). He then equated a hit with changing the trajectory of the asteroid exactly enough to absolutely hit Earth.


The term "satellite" doesn't always refer to the shiny billion dollar projects orbiting earth.

The moon is a satellite to earth, as the asteroid belt is a satellite to the center of our solar system, the sun.

Just a penny in the fountian


RE: I'm ashamed
By mwadley on 4/16/2008 11:56:42 AM , Rating: 4
Using this kids calculations, I believe that I can stand in front of a moving train and slow it down by about 0.1 mph with a 1 in 10 chance of survival. LOL.


RE: I'm ashamed
By Polynikes on 4/16/2008 11:59:06 AM , Rating: 2
Wow, that kid just made me feel stupid.


RE: I'm ashamed
By tanishalfelven on 4/16/2008 2:56:03 PM , Rating: 2
no reason to feel stupid untill we see his math. for all we know (he made stuff up).

like others i'm hoping someone can find his math so i that we can look at it.

ps. i am not ready to admit i'm dumber than a 13 year old without solid proof.


RE: I'm ashamed
By LatinMessiah on 4/18/2008 6:27:39 PM , Rating: 2
Isn't there a TV game show called "Are you dumber than a 13 year old"?


Deflected orbit increases chances that much
By HOOfan 1 on 4/16/2008 10:51:18 AM , Rating: 5
What is the chance that a 200 Billion Ton Asteroid will be deflected that much by a 2-4 Ton Satellite?

I would like to have seen some comments from experts who have examined this boy's calculations. Afterall he made these calculations, with data collected by people other than himself.

I am not saying he can't be correct, but this article doesn't give enough information about the boy or his calculations or even the data he used to make them. Anyone can make claims like these, whether they are qualified to or not.




By masher2 (blog) on 4/16/2008 11:11:11 AM , Rating: 3
> "What is the chance that a 200 Billion Ton Asteroid will be deflected that much by a 2-4 Ton Satellite?"

Well, the relatives velocities are on the order of 12 km/second. That's 20 times the speed of a bullet.

Also, the 'deflection' involved is negligible. It's the very small loss in velocity the asteroid receives, which will cause it to strike the earth on it's next pass.

Losing velocity, even a minor amount, right as you pass a celestial body is equivalent to that body having a stronger gravitational field, which dramatically increases the chance of capture.


By cochy on 4/16/2008 11:11:52 AM , Rating: 2
Well the thing is, it doesn't need to be deflected too much initially because it only requires enough of an initial change to effect where it ends up 7 years later on. Still seems pretty far fetched.


RE: Deflected orbit increases chances that much
By Murst on 4/16/2008 11:30:46 AM , Rating: 2
quote:
What is the chance that a 200 Billion Ton Asteroid will be deflected that much by a 2-4 Ton Satellite?

You're looking at it the wrong way. You can't just compare the mass of the asteroid to the mass of the satellite.

You have to factor in the velocity. Remember physics? Force = mass * accelaration.

So, just because the mass of the satellite isn't that much, you need to keep in mind that it is moving at a very high speed. The force generated by a collision, especially if the satellite and asteroid would happen to be moving in somewhat opposite directions, would be huge.


RE: Deflected orbit increases chances that much
By cochy on 4/16/2008 11:33:32 AM , Rating: 2
Would it be? The satellite is moving fast, but how fast is the asteroid moving and how much of a difference if any does that make?


RE: Deflected orbit increases chances that much
By masher2 (blog) on 4/16/2008 11:36:51 AM , Rating: 2
The asteroid is moving much faster than the satellite...but that's a moot point. What matters is the relative velocity between the two.


By Amiga500 on 4/16/2008 11:49:42 AM , Rating: 4
What also matters is how much it has to move in 2029 to hit next time round.

If its only a nanodegree change of course...


By HOOfan 1 on 4/16/2008 12:23:27 PM , Rating: 3
I am not really qualified to comment at all, but wouldn't it also depend on what degree the strike occurs? Also if it is a head on strike, versus a strike occuring because the asteroid overtakes a satellite, in which case the satellite's velocity actually decreases its impact on the asteroid.

Just seems like very many variables and the article didn't state how many variables the boy took into account.


By cochy on 4/16/2008 12:41:35 PM , Rating: 2
True.


By General Disturbance on 4/16/2008 11:54:29 AM , Rating: 1
No he's right. The satellite can be considered with zero velocity because the asteroid is moving so fast, and of course the frame of reference is the earth and that is what the satellite is orbiting around.
In a perfectly inelastic collision, which this would likely be closest to, the velocity of the asteroid would simply slow down by the ratio of old_mass/new_mass, where new_mass is old_mass of the asteroid plus the satellite mass, so using the numbers given
200e9/(200e9 + 4) = 0.9999999999800000000004.
That's a change in the 11'th decimal place! Someone else can do the calculation to show how long it would take for that to affect the position of the asteroid appreciably. Well, it would be approx 1500 years of travel for it to change its position by one meter.


By General Disturbance on 4/16/2008 12:05:18 PM , Rating: 2
ah, sorry, it would actually be ~144 YEARS for every KM of displacement, order of magnitude of course.

However, I think the kid actually did it doing what I explained above with the ratios of cross-sectional area.


By Tsuwamono on 4/16/2008 12:08:43 PM , Rating: 2
I gotta go back to school....


RE: Deflected orbit increases chances that much
By masher2 (blog) on 4/16/2008 12:13:10 PM , Rating: 2
> "No he's right. The satellite can be considered with zero velocity because the asteroid is moving so fast..."

No. The *relative* velocity is what counts. Asteroids generally run in the range of 5-15 km/sec. Geosynch satellites about 3 km/sec. Without looking up the exact numbers for Apophis, the satellite velocity is still very relevant.

> "Well, it would be approx 1500 years of travel for it to change its position by one meter. "

Actually, its more like 1 meter variance every 500K seconds...or once every 8 days or so.


By General Disturbance on 4/16/2008 12:24:43 PM , Rating: 2
Well, it's the ratio of momenta that counts, and that is still negligible.

Also, the velocity vectors might not be opposite, they may be perpendicular, same direction, etc. I believe Apophis is inclined significantly to the equatorial plane.

But yes, it could increase the delta v by a small amount if you consider satellite velocity...but I mean it's still all quite negligible.


2036?
By ihova01 on 4/16/2008 12:00:44 PM , Rating: 3
Don't you worry guys. Most of us will be dead by that time anyway.




RE: 2036?
By ihova01 on 4/16/2008 12:05:12 PM , Rating: 3
And the current generation will be facing much more serious problems than the asteroid hit.


RE: 2036?
By FITCamaro on 4/16/2008 12:45:31 PM , Rating: 3
Yeah global cooling is going to be a bitch.


RE: 2036?
By martinrichards23 on 4/16/2008 12:53:35 PM , Rating: 5
I'm still worried y2k is going to kick in.


RE: 2036?
By weskurtz0081 on 4/16/2008 1:02:56 PM , Rating: 2
Yeah, your right. I am so worried about the future and the economy that I am just going to sit in my home and do nothing..... it's really the safest thing to do.

And, with Global "COOLING" on the horizon, it looks like I better start buying more warm clothes. All those damn bathing suits I bought for global warming are pretty much a waste of money now.


RE: 2036?
By V3ctorPT on 4/16/2008 1:02:14 PM , Rating: 2
hum... I'll be 49 that year... i'll better start taking loans and at least live a good life when the asteroid hits us...


RE: 2036?
By ihova01 on 4/16/2008 2:10:36 PM , Rating: 2
Yes, you will if cancer doesn't bury you first.


RE: 2036?
By Durrr on 4/16/2008 7:46:54 PM , Rating: 2
don't forget about the genetically re-engineered measles to cure to cancer


Another Article that NASA isn't Wrong
By Brainonska511 on 4/16/2008 11:07:48 AM , Rating: 6
http://www.theregister.co.uk/2008/04/16/esa_german...

According to The Register, NASA is correct and the boy was wrong with his calculations.




RE: Another Article that NASA isn't Wrong
By masher2 (blog) on 4/16/2008 11:20:35 AM , Rating: 4
Nice find. It appears that NASA considered the possibility of a satellite strike after all, but discounted it for the following reason:
quote:
[The asteroid will pass] within the distance of Earth's geosynchronous satellites. However, because Apophis will pass interior to the positions of these satellites at closest approach, in a plane inclined at 40 degrees to the Earth's equator and passing outside the equatorial geosynchronous zone when crossing the equatorial plane, it does not threaten the satellites in that heavily populated region


RE: Another Article that NASA isn't Wrong
By Amiga500 on 4/16/2008 11:55:25 AM , Rating: 1
Hmmm.

That NASA quote is a careful play with words.

They are assuming it won't strike a satellite because it won't pass through the region of greatest concentration of said satellites.

That doesn't actually rule out it striking a satellite. :-)

Anywayz the real question is... would it be feasible to screw with the asteroid's path first time around so it has zero chance of impacting the earth 2nd time around?


By Chernobyl68 on 4/16/2008 12:04:09 PM , Rating: 2
RE: Another Article that NASA isn't Wrong
By cvmaas on 4/16/2008 1:21:07 PM , Rating: 2
EXACTLY what I was thinking.. There are plenty of satellites that aren't in a geostationary orbit. Not to mention what happens to birds that are in the geo orbit at the end of their mission. You have 2 options, try to pull the bird back into Earth, hoping it will burn up on re-entry. Or the easier option, to push the bird out further into a graveyard orbit, where the asteroid WILL pass.

I don't remember the exact figure, but there is something like 12k satellites and pieces of debris orbiting the Earth.

The worry is that the asteroid will strike one of these satellites and lose a VERY small amount of velocity, and possibly even alter its trajectory on the order of something like 0.00001 degrees. These two factors will both cause Earths gravitational field strength as seen from the asteroid to increase by their square as the asteroid gets closer to the planet.

Everyone here is calculating the velocities, but negating the DISTANCE traveled. Sure, if there is an impact, the resulting delta V will be very small, but over a VERY large distance, it adds up. As it adds up, the gravity field strength increases by the square of the distance.

NOW, having said all that, the 1 in 450 worry is that these small changes over time and a large distance will cause the asteroid to be "captured" by the Earth, because honestly, 33,000km isn't very far in Space terms. The HOPE is the asteroid will skip off the top of Earths Atmosphere and keep on going. If you have ever skipped rocks across a pond, you know the risk we are talking about.


RE: Another Article that NASA isn't Wrong
By Carter642 on 4/16/2008 2:44:43 PM , Rating: 2
To be captured into earth orbit would require the asteroid to shed a whole lot of velocity. Even if we piled up every satellite we have in orbit infront of this thing we wouldn't be able get anywhere close to that kind of delta v.

NASA says that at that point in orbit the differential between earth and apophis is going to be about 5km/s without the effects of earth's gravity, were it to hit earth it would be doing about 12km/s at impact. That's way too much velocity for anything we can muster to affect. It will defelct quite a bit on it's way by die to earth's gravity. Lets hope that it eventually deflects far enough to fall into an orbit of one of the inner planets or fall into the sun.


By masher2 (blog) on 4/16/2008 2:56:19 PM , Rating: 2
> "To be captured into earth orbit would require the asteroid to shed a whole lot of velocity"

Right, but that isn't what's being postulated here. The issue is whether or not the asteroid would pass through the gravitional keyhole...which alters its course just enough to strike the earth on its next pass.


Serious comment
By Tsuwamono on 4/16/08, Rating: 0
RE: Serious comment
By masher2 (blog) on 4/16/2008 12:22:48 PM , Rating: 2
If you want to survive an asteroid impact the size of Apophis (or even several times larger), you just need a moderately high-altitude cave (or one very far from any coast or river), along with a year-long supply of food and water.


RE: Serious comment
By polarity on 4/16/2008 12:25:38 PM , Rating: 1
The world's coastal areas are the most heavily populated. If every plane in existance was pressed into service it wouldn't make much difference.

Even if you could move everyone out of the danger zone, that's a lot of displaced people. Think of the chaos and suffering that happens in refugee camps, and increase that by several orders of magnitude.


RE: Serious comment
By masher2 (blog) on 4/16/2008 12:58:22 PM , Rating: 2
Hm, I wonder if you get an automatic downrate for replying to a -1 comment?

You're right, but the problem is even worse than that. Large tsunamis like this travel up rivers also...and nearly all large cities are on a river.


RE: Serious comment
By cochy on 4/16/2008 1:23:37 PM , Rating: 2
hmm yes looks that way. Guess they want to discourage replying to -1 posts.


RE: Serious comment
By Etsp on 4/16/2008 3:54:53 PM , Rating: 2
It's to deter people from "feeding the trolls" as they say.


RE: Serious comment
By martinrichards23 on 4/16/2008 12:56:32 PM , Rating: 2
Either that or we build a giant baseball bat and hit it towards the sun for a home run.


RE: Serious comment
By prenox on 4/17/2008 12:01:06 AM , Rating: 2
I guess you could pull a guitar from some Japanese kids head and use that to hit it out.


RE: Serious comment
By cochy on 4/16/2008 1:22:32 PM , Rating: 1
How this that comment rated -1? Man that was funny stuff.


RE: Serious comment
By AssBall on 4/16/2008 2:17:21 PM , Rating: 1
As Masher pointed out the plan kinda blows. There are several reasons. I think of an asteroid impact as more of a several year ordeal that completely fucks our (read: human race's) environment, social structure, and economy. And by completely fucks I mean 3-6 billion people DIE.

That being said I still wouldn't complain if an A380 saved me from a tsunami...


RE: Serious comment
By tanishalfelven on 4/16/2008 6:12:17 PM , Rating: 2
oh well. atleast we won't have to worry about the population crisis anymore.

j/k.... or am i ?


Calling Dr. Newton...
By Reclaimer77 on 4/16/2008 5:58:27 PM , Rating: 2
I'm fairly certain there is NO WAY something with the mass of 200 BILLION tons traveling through space would have its trajectory altered by a collision with something as miniscule in comparison as a satellite orbiting the Earth.

It would be like claiming a Mac truck could be altered by a collision with a dragonfly at interstate speeds.




RE: Calling Dr. Newton...
By Basilisk on 4/16/2008 7:31:55 PM , Rating: 2
You comfortably neglect to place the event in its context, as opposed to yours: put that Mac truck and its innocent butterfly in space, let them impact at 70 mph relative velocity, then examine the truck's accumulated deviation after it's orbited the sun for about 5 Billion orbital miles [a raucously unjustified estimate of that rock's travel between the two passes -- please fill in the correct number].

You'll find the driver is sadly off in his delivery schedule/location, and deeply pissed at all the freakin' butterflies out in space.


RE: Calling Dr. Newton...
By Reclaimer77 on 4/16/2008 8:41:03 PM , Rating: 2
I'm sorry but the disparity of momentum, mass, and velocity is too great. I don't think you understand how massive this asteroid is. Your also using the best case scenario in that the asteroid WOULD hit a large number of orbiting objects, which NASA has already disproved this kids claim of that.

Check my math. Using the standard measure of momentum and the known data on this asteroid, I have determined that Apophis moving at 45,000 kph with a weight of 40,823,313,300 kilograms has a momentum of 5,102,914,162,500 kilogram meters per second. The standard unit of momentum. Thats uhhh.. A LOT !

However, lets say your right. Are you forgetting that every time it orbited the sun it would pick up the velocity you claim it would lose due to the suns gravitational pull ?


RE: Calling Dr. Newton...
By Reclaimer77 on 4/16/2008 8:44:00 PM , Rating: 2
typo edit :

I typed " weight " where I meant to type " mass " in the math part. Sry.


RE: Calling Dr. Newton...
By SlyNine on 4/17/2008 2:21:46 AM , Rating: 2
The Mac truck has stored power to compensate for any slowdown, where as the Asteroid is riding on shear inertia. Third law. For every action there is an equal and opposite reaction. No matter how small or big. Remember we are talking vast distances and vast amounts of time.


RE: Calling Dr. Newton...
By Reclaimer77 on 4/17/2008 8:33:09 AM , Rating: 2
quote:
The Mac truck has stored power to compensate for any slowdown, where as the Asteroid is riding on shear inertia. Third law. For every action there is an equal and opposite reaction. No matter how small or big. Remember we are talking vast distances and vast amounts of time.


It was just an analogy. Obviously the " mac truck " is being subjected to stresses not found in space. Like gravity and friction loss from its tires and wind resistance etc etc. However even a Mac truck coasting without power would not be effected by bug impacts in any significantly measurable way.

I'm well aware of the Third Law obviously. And yes, there would be SOME reaction from Apophis hitting a satellite. But the reaction would be so minute as to be not measurable. And certainly not nearly enough to cause a course change in the asteroid.

Distances and time are irrelevant for this discussion. The moment of impact is the key. Would something with over five trillion units of momentum be effected in a measurable way from hitting something with the tiny mass and density of an orbiting satellite ? Thats is the question here.

I brought up density because its key. Satellites are not hardened balls of ore and rock like and asteroid. The impact would also be lessoned by the fact that satellites are frail structures. Upon impact the satellite would be crushed and smashed onto the asteroid. The entire mass of the satellite will not be given a chance to directly impact the asteroid all at once. This is also assuming a direct impact and not a glancing blow, which is also entirely possible given the scenario.

I'm not claiming to be a know it all. I used some easy and proven math that anyone can find on Google and a dose of common sense. Plus I love reading Steven Hawkins ! :) I just don't think there is ANY WAY Apophis would be effected by orbiting satellites. Its going to take more than analogies and conjecture to change that.


RE: Calling Dr. Newton...
By masher2 (blog) on 4/17/2008 11:37:53 AM , Rating: 2
> "Distances and time are irrelevant for this discussion"

On the contrary, distance and time are the key factor here.

Your Mac truck analogy fails for the simple reason that, on earth, friction damps out tiny changes in inertia. But in space, even the smallest change will eventually show up in an orbital change, given enough time and distance (and assuming the object isn't in a potential energy well).

> "The impact would also be lessoned by the fact that satellites are frail structures"

No, not in the least. The only thing "crumpling" does is spread out the momentum transfer in time. That make's the maximum decelleration felt by the objects in the collision smaller...but the total momentum transferred is idential.

An impact with a 4-ton satellite would most certainly affect Apophis. It would have been a measureable change even with the original (incorrect) mass of 200B tons. With the correct mass of 20M tons, the change would obviously be far larger.


Defense
By waltzendless on 4/16/2008 11:21:34 AM , Rating: 3
What we need is a frikkin "laser" on the moon.




RE: Defense
By polarity on 4/16/2008 12:20:51 PM , Rating: 2
Actually not a bad idea, so long as it's very big. Could be solar powered so no worries about energy.

Just point it at the asteroid, and blast away. If they can push sailboats around with little lasers, just from the impact of a few photons, then I'm sure the impulse from a much bigger laser vapourising large amounts of an asteroid's surface is sure to change it's orbit enough that it'll miss the earth. More than it hitting a sattelite anyway.


RE: Defense
By bobobeastie on 4/16/2008 5:34:08 PM , Rating: 2
quote:
If they can push sailboats around with little lasers


The only time laser and sailboats are used in the same sentence is in referring to these http://en.wikipedia.org/wiki/Laser_%28dinghy%29.

As a slightly competitive sailer I would contest the offending laser using sailboat by doing a 360, and then I would send in the Sea Bass.

Or perhaps you're talking about solar sails or laser sails for space travel?


RE: Defense
By suryad on 4/16/2008 1:21:00 PM , Rating: 1
That sounds like austin powers ROFL and if it is it cracked me up!


RE: Defense
By taropie on 4/16/2008 3:31:50 PM , Rating: 2
Nah, just give a call to China to blast a few of their rockets at it.


nobody likes a smartarse....
By clb3 on 4/16/2008 10:48:30 AM , Rating: 2
seriously though doesnt anybody else think that orbiting satellites should have been taken into account in the first place. not particularly well read on space etc but leaving 20,000 of them out of the initial calculation seems a little ridiculous...




RE: nobody likes a smartarse....
By clb3 on 4/16/2008 10:49:09 AM , Rating: 2
sorry, 40,000


RE: nobody likes a smartarse....
By masher2 (blog) on 4/16/2008 11:45:04 AM , Rating: 2
The sphere encompassing geosynchronous orbit is over 52,000 miles in diameter. That's a surface area of 34 billion square miles. You could put all 20,000 of those satellites together in less than one square mile.

The chance of a random strike is pretty much negligible, unless the asteroid cuts through that sphere at an angle almost tangent to it.


RE: nobody likes a smartarse....
By SlyNine on 4/17/2008 2:23:57 AM , Rating: 2
Then agian we are talking about a one in what was it, 1 in450,000 chance of it hitting earth in the first place. Is that more or less then the chance of it hitting a satellite?


Incorrect math in this article itself?
By mikeblas on 4/16/2008 11:36:16 PM , Rating: 2
Is the math in this article correct? I don't think it is.

It says that a 1049-foot-wide ball of iridum and iron would weigh 200 billion tons. We don't know what mix of iridium and iron would be in there, so let's assume it's 100% iridium, because that's much heavier than lead. It's density is 22.42 grams per cubic centimeter.

A ball that's 1049 feet wide has a radius of 524.5. It's volume is 4/3*pi*524.5^3, which is 604,400,878 cubic feet. That's 17,114,829,345,885 cubic centimeters, at a density of 22.42 grams per cm^3, giving 383,714,257,124,075 grams.

That's about 844,171,365,672 pounds, or 422,085,682 tons ... about 500 times less than the number quoted in this article.




RE: Incorrect math in this article itself?
By masher2 (blog) on 4/17/2008 12:25:04 AM , Rating: 2
Good catch! Your math is correct (though doing that in English units is enough to give one headaches).

The actual mass of Apophis is 2.1E10 kg...which is 21 million metric tons -- about 10,000 less than the figure in the article text.


By mikeblas on 4/17/2008 1:45:53 AM , Rating: 2
Yeah; I couldn't find reasonable conversions for the metric units I wanted. Not much loss in going back and forth, though; especially when the quoted figure is 2.5 orders of magnitude off.

Where's the "American Software Developer notices fault in DailyTech Article Calculations" article? Can I provide my own snarky picture for the header?


Al Gore
By UppityMatt on 4/16/2008 11:30:19 AM , Rating: 5
It doesn't even matter... Al Gore sent me data in an email that by the year 2036 ManBearPig will have already decimated the human race. It was in an Excel Spreadsheet ill link later




Errors galore
By Shadowself on 4/16/2008 12:32:15 PM , Rating: 5
First, there are not 40,000 "satellites" unless you believe virtually every piece of space junk out there is a "satellite".

Second, most of this junk is on the order of a few pounds or less. Some are as heavy as a large satellite (a few thousand pounds), but most are not.

Third, most of the space junk is in relatively low Earth orbit -- a very small fraction is near the highest probability flyby altitude of 32,500 km.

Fourth, only a small fraction of the satellites are in GEO or GSO (approximately 35,786 km) and virtually none are near the highest probability flyby altitude of 32,500 km.

Fifth, the asteroid is coming in on its first flyby at a significant inclination from the equitorial plane and virtually all the GEO and GSO satellites are near that plane -- thus the probability of traversing the path of any GEO or GSO satellite is exceedingly small.

Sixth, it is possible to move these GEO and GSO satellites for a short period of time if in the days leading up to the first flyby it appears there is a reasonable probability of impact with one of them -- it will inconvenience users for a day or so, but it will have much less impact (pun intended) than an Earth impact in 2036.

Seventh, these probability calculations require the use of relatively complex mathematics (3D probability densities as a function of time as laid over another set of probability densities as a function of the same time series) to be even reasonably accurate. Doing simple equations like those shown in responses to this article will be exceptionally lucky to be within a factor of 1,000 of the real probabilities.

And on and on...