Schoolboy Corrects NASA's Math On Killer Asteroid

spiracle writes "A German schoolboy, Nico Marquardt, has revised NASA's figures for the chances that the Apophis asteroid will hit earth. Apparently if the asteroid hits a satellite in 2029, its path could be diverted enough to cause it to collide with Earth on the next orbit, in 2036. NASA had calculated the chances as 1 in 45,000 but the 13-year-old, in his science project, made it 1 in 450. NASA agreed." Update: 04/16 16:47 GMT by Z : This is not entirely accurate, it turns out — more details.

Not peer reviewed.

[Plazmid]

Not peer reviewed.

Other news stories on this

[goombah99]

NASA previously estimated the chance "Apophis" the asteroid would strike earth in 2027 was 1 in 45,000. But a german schoolboy, Nico Marquardt, pointed out that NASA overlooked the probability the asteroid would strike one of the 40,000 sattelites orbiting Earth and enter a new solar orbit intersecting Earth in 2036. A german newspaper reports that NASA now concurs the chance this will happen is about 1 in 450. If the 200 billion tonne ball of iridium and iron stikes the planet then it's literally light's out for earth: 800 foot tidal waves followed by an indefinite period of dust cloud covered darkness, not to mention metal vapor in the atmosphere. The original Slashdot discussion [slashdot.org] was in 2007 when the odds were better. At that time it was known that there was a small risk of a gravitational slingshot dropping it into the 2036 collisional orbit, however, to do so the asteroid had to pass through an improbable 400 meter wide strike zone to be properly deflected, as described in 2006 in Popular Science [popularmechanics.com] from 2006. Today's announcement of the new finding is here [physorg.com]and here [yahoo.com].

Friday the 13th

[goombah99]

By the way, it passes by the earth in 2027 on friday the 13th. If it hit's it will hit in the pacific ocean. So California may get wet. The energy content is said to be 26,000 Hiroshimas which is not that much but recent calculation suggest is more than enough to darken the earth.

Re:Friday the 13th

[terrymr]

> 26,000 Hirshimas

So a little less than 1 Mt St Helens then.

Re:

[ricree]

True, perhaps, but 1 Mt St Helens isn't that terrible contained in a relatively small area (of course, with anything of this magnitude small is a very relative term). If something like this were to hit in the pacific, what would the tsunami produced by such an event be like?
The wikipedia article for the 2004 Indian Ocean tsunami states that the earthquake released around the equivalent of 1502 Hiroshimas, so we're talking over an order of magnitude difference. That said, a lot of the death toll in 2004 was

Re:Friday the 13th

[jd]

Volcanic ash, when mixed with crushed limestone, makes some of the best concrete. At least, the Romans thought so. That's what they used. Set underwater, was strong enough to use on big construction projects like the Colleseum, and so on. (Concrete appears to have been invented by the Egyptians - the upper levels of the pyramids show evidence that the limestone was poured into place, not set as a naturally-formed rock.) I suspect ash from Mount St. Helens would be excellent in a Roman-recipe concrete.

Also on the theme of Mount St. Helens, it stopped building the dome inside the crater at about the same time as swarms of earthquakes were detected off the coast of Oregon (usually a precursor to volcanic activity). There are no volcanos in the area the earthquakes were detected, so vulcanologists have ascribed the tremors (reaching 5.5 on the richter scale) to a shift in the magma flow. There was no suggestion - as far as I can tell - that the lack of mountain-building and the earthquakes were linked, but it wouldn't shock me. If that is corrct, then there's an awful lot of molten rock going somewhere - the dome was building a dumptruck's worth of rock per second, according to one quote I saw - and there are a lot of volcanos considered overdue for exploding.

Re:

[commodoresloat]

Volcanic ash, when mixed with crushed limestone, makes some of the best concrete. At least, the Romans thought so. That's what they used.

Of course, they're dead now.

Re:Friday the 13th

[Missing_dc]

Not so, Sir. They EVOLVED into Italians.

Re:Friday the 13th

[Bender0x7D1]

This asteroid would do 1d4 wombats of damage to each of the 130 million items in the Library of Congress. However, because of their binding (creating a rigid spine area), each of the 29 million books would take an additional 1d4 wombats of damage. So we can call the total damage as 159x10^6d4 wombats of damage to the Library of Congress.

Re:

[NewbieProgrammerMan]

If it hit's it will hit in the pacific ocean. So California may get wet.

Is that in the same way that ~250k people in India, Indonesia, Malaysia, the Maldives, Myanmar, Somalia, Sri Lanka and Thailand "got wet" after the earthquake in 2004?

Re:Friday the 13th

[MrNaz]

26,000 Hiroshimas?! Why, that's almost an Africa!

Re:Friday the 13th

[Kjella]

The energy content is said to be 26,000 Hiroshimas

Huh, wait a second. The estimates for the Hiroshima bomb is 13-16 kiloton which would make it in the 340-415 megaton range. That's just 8 times the Tsar Bomba of 50 megaton the Soviets tested, and last I checked the world did fine. That number must be way off or the potential damages way exaggerated.

Fuzzy math

[commodoresloat]

Huh, wait a second. The estimates for the Hiroshima bomb is 13-16 kiloton which would make it in the 340-415 megaton range. That's just 8 times the Tsar Bomba of 50 megaton the Soviets tested, and last I checked the world did fine. That number must be way off or the potential damages way exaggerated.

Sounds like they need another German schoolboy to help them out here.

Re:

[besalope]

Hiroshima wouldn't see a drop of water. It's relatively shielded by the island Shikoku. Tokyo on the other hand might be saved only if Godzilla intervenes.

Re:Friday the 13th

[MichaelSmith]

Tokyo on the other hand might be saved only if Godzilla intervenes.

Thank God. I thought there was going to be no hope at all.

Re:Friday the 13th

[SatanicPuppy]

You ever go to the mall and drop a quarter in one of those funnel things? You know how it rolls around and around? Now, imagine putting something in front of the quarter...What will happen?

It'll slow down slightly, and the loss in speed will cause it to zip down the funnel.

That's what we're dealing with here. If this thing loses enough velocity, our gravity well will suck it in. If we could give it a push as it is on it's way past us, sure, we could get rid of it, but putting things in front of it is always going to be bad for us.

In related news

[goombah99]

Congress announced today that there's a 1 in 450 chance you will be eligible for social security at retirement.

There's an alanis morriset kind of irony here. If we were just moneys in trees and had not put up the sattelites we would not have magnified our risk a 100 fold.

Given that sort of cosmic irony, I predict it has to hit Hubble.

And speaking of hubble they should have known it had a faulty mirror when they say the stencil on it that said "asteroids in mirror are closer than they appear".

Thank you, thank you. I'll be here all week. Try the veal.

Google translation of German source

[goombah99]

Here's the (semi hilarious) machine translation [google.com].

I forgot the World Downfall chosen! ... AND NASA HAS SAID, I HAVE QUITE

BY MICHAEL SAUERBIER

Potsdam - He is the greatest threat our planet: On Sunday, 13 April 2036, the asteroid crosses "Apophis" the orbit.
Nevertheless, the probability that we killer lumps from the All true, is 0.2 percent! This is a student from Potsdam calculated.

And doing so, Nico Marquardt (13) the research of NASA corrected! For his disturbing discovery was the small physics genius now for the youth researchers Prize.
"The asteroid has left me no rest," says the SiebtklÃssler from Potsdamer Humboldt Gymnasium. "On the Internet, I had high bets on the impact of Apophis was discovered. But NASA is the impact likely only 1 to 45000. I wanted to know how it really is. "
With the telescope of the Astrophysical Institute Potsdam Nico was allowed to observe asteroids train.
The student: "Then I said Spahn professor at the University of Potsdam, as the attractions of the sun, moon and earth the way of Apophis influence." Astrophysicists had a suitable formula.
Nico: "With Professor Landgraf, ESA's satellite control center, I train then recalculated."
Frightening picture: "The harvest probability is 1 to 450," said a young astronomer. For comparison: For a lottery-six (without super number), it is at 1 in 14 million.

Nico: "When would the impact force of 98000 Hiroshima bombs freely. Stürben million people, dust would darken the sky, a super-tsunami swamped parts of the earth. "
But: "I hope that Apophis nearly vorbeischrammt to us ..."

Re:Google translation of German source

[thodi]

No need to translate it to make it hilarious:
a) The source "newspaper" is Germany's biggest tabloid - with as much knowledge on astrophysics as a kindergarten kid
b) No 13 year old German kid says "stuerben"

*** STOP PRESS ***

[PinkyDead]

This just in: Kindergarten kid corrects 13 year old student's earlier correction of NASA calculation.

Chance of impact now 1 in 4.

Toddler's have be banned from using calculators for fear they will doom us all.

Doom Us All, I tells ya!

His peers

[goombah99]

Still, no one has scrutinized the boy's work for math errors.

Well surely we can find another school boy to peer review it.

Re:His peers

[RuBLed]

Thoughts of another schoolboy:
"But if we make it strike the Earth and not one of those sattelites in 2029, the probability of it striking the Earth in 2036 is NIL. NASA agreed."

*whoosh*

[grahamd0]

  o-- -  *whoosh*
    ^ the point

     O
    -|-  <- You
    / \

Re:His peers

[arivanov]

We just need to make sure it is in a place like Germany, France or Russia where they still teach terrorist material like mathematics, physics and chemistry in school.

You damned kids!

[sm62704]

Dilbert [dilbert.com] on the "Millineum generation"

Now get off my lawn! Damned kids! And take your calculators with you! (grumble mumble where'd I put my lawnmower?)

Re:Other news stories on this

[arivanov]

That should be "Do not start cloning Bruce Willis just yet". Fixed that for ya...

We are talking 2036 after all... Unless it will be a tragicomic spoof of both Space Cowboys and Armageddon.

Re:Other news stories on this

[Digestromath]

If nobody has criticised it yet, that means its every /.ers responsibility to, regardless of thier actually knowledge of the facts or math.

So I'll bite the bullet.

First off... how does a 200,000,000,000 tonne asteroid (200,000,000,000,000 kg) travelling at any substantial inter-planetary speed be deflected by a satellite travelling at 3070 m/s and at most wieghing 10,000kg?

Of course thats presuming an elelastic collision as opposed to the satellite deflecting off the asteroid in a cloud of debris.

Its been a while since I've done any physics, and I'm just grabbing numbers from the article (which are likely to be wrong anyways).

But to bring it all together in a car analogy for the fellow /.ers... How does a .22 bullet deflect an oncoming semitruck forcing into the little old lady on the sidewalk?

Re:Other news stories on this

[amRadioHed]

But to bring it all together in a car analogy for the fellow /.ers... How does a .22 bullet deflect an oncoming semitruck forcing into the little old lady on the sidewalk?

Aim for the driver.

Re:Other news stories on this

[MichaelSmith]

So I'll bite the bullet.

First off... how does a 200,000,000,000 tonne asteroid (200,000,000,000,000 kg) travelling at any substantial inter-planetary speed be deflected by a satellite travelling at 3070 m/s and at most wieghing 10,000kg?

It gets deflected by a small degree, but because this object makes close approaches to large objects like Earth, small impulses can have their affect amplified.

This object is in an orbit which resonates with our own orbit. It is certain to continue close approaches with Earth until either (1) it hits us or (2) is thrown into a totally different orbit, most likely as a result of a very close approach.

Re:Other news stories on this

[icebrain]

Multi-body orbit problems are highly chaotic... part of my senior design program was writing a program to simulate this asteroid's trajectory and a spacecraft observing it to refine the data, then projecting the refined data forward. Essentially, we wanted to find out how long we would need to observe said asteroid in order to get our error ellipse down to a specified level.

Turns out that even tiny velocity changes (well below 1m/s) had huge effects on the rest of the trajectory. If our spacecraft's first measurement was off in the wrong direction, our solution never converged in the time we needed it to.

Re:Other news stories on this

[Captain Nitpick]

First off... how does a 200,000,000,000 tonne asteroid (200,000,000,000,000 kg) travelling at any substantial inter-planetary speed be deflected by a satellite travelling at 3070 m/s and at most wieghing 10,000kg?

The same way sunlight can push a 270m rock around. Lest you think I am kidding, let's read what NASA has to say about that:

For example, the team found solar energy can cause between 20 and 740 km (12 and 460 miles) of position change over the next 22 years leading into the 2029 Earth encounter. But, only 7 years later, the effect on Apophis' predicted position can grow to between 520,000 and 30 million km (323,000 and 18.6 million miles; 0.0035-0.2 AU).

The effect of a small force integrated over years and a few billion miles produces a significant effect. In this case a relatively small deflection gets magnified by the 2029 flyby.

Of course thats presuming an elelastic collision as opposed to the satellite deflecting off the asteroid in a cloud of debris.

Its been a while since I've done any physics, and I'm just grabbing numbers from the article (which are likely to be wrong anyways).

It's obviously been a long time. Any impact will impart momentum to the asteroid. I don't know if you mean "elastic" or "inelastic", but it doesn't matter. Bits of satellite bouncing off the asteroid represent momentum transferred from the asteroid.

But to bring it all together in a car analogy for the fellow /.ers... How does a .22 bullet deflect an oncoming semitruck forcing into the little old lady on the sidewalk?

Bad analogy. The elasticity and friction of the tires cancel out any effect of the impact. These effects don't exist for an asteroid.

A better analogy would be a bowling ball on a lane with one pin. There's a tiny pebble halfway down the lane. How does a 1g pebble deflect a 12 pound bowling ball? By getting run over. If the lane was 100 miles long, a grain of salt would have a significant effect on where the ball ends up.

Re:Other news stories on this

[mysticgoat]

I'll play along. I'm qualified to do so on this forum: I've read slashdot for years and I've never studied orbital mechanics or anything else pertinent to the subject.

The original NASA estimate was based on the probability that on the previous orbit Apophis would hit a small window of opportunity that would slingshot it around Earth into the final collision orbit. What the kid did was demonstrate that the window is actually much larger than NASA had first estimated, since collisions with small stuff known to be orbiting the Earth could funnel Apophis into the slingshot zone.

Oh, you wanted a car anology:

Consider a photographer at an auto race who has jumped the safety barrier to get some real good photos of the cars roaring into a hairpin turn. He knows that there is some small risk that a car will spin out as it approaches him and smash him flat, but to his mind it is an extremely low risk. There is only a narrow trajectory that would cause him danger.

But what if a bunch of ball bearings had been strewn onto the track in front of the curve? That changes the whole equation: if a race car teetering on the verge of spinning out hits one of these, it is much more likely to plow into the luckless photographer. The range of dangerous trajectories is much wider than the photographer estimated, since the track is not as clean as he pictured it in his mental model.

Re:Other news stories on this

[Peaker]

http://www.theregister.co.uk/2008/04/16/esa_german_schoolboy_apophis_denial/ [theregister.co.uk]

Re:

[SleepyHappyDoc]

You were probably going for +5, Funny, but I think you might be on to something. Turn this sucker over to some company, who can have all the ore, as long as they make sure to grab it all and address the safety concerns before it gets here.

Re:Not peer reviewed.

[goombah99]

You are right that NASA has not updated it's site since 2006. Here's what they said a while back [nasa.gov]:

The future for Apophis on Friday, April 13 of 2029 includes an approach to Earth no closer than 29,470 km (18,300 miles, or 5.6 Earth radii from the center, or 4.6 Earth-radii from the surface) over the mid-Atlantic, appearing to the naked eye as a moderately bright point of light moving rapidly across the sky. Depending on its mechanical nature, it could experience shape or spin-state alteration due to tidal forces caused by Earth's gravity field.

This is 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.

So what is being claimed here is not so implausible. It is going to pass within the geosynconous orbit distance.

Re:Not peer reviewed.

[Colonel Korn]

Thinking about the likelihood of a satellite collision in the first place, and then the probability that it would adjust the orbit of Apophis so that it would impact Earth, I'm going to have to intuitively agree with NASA on this one. The odds of an impact with a satellite should be vastly below 1 in 450, which alone means that this should be wrong. Let's wait for a real account of this, not a pop-media summary with a lot of holes.

Re:Not peer reviewed.

[commander_gallium]

You are right that NASA has not updated it's site since 2006.

Just to be clear, the Impact Risk Page [nasa.gov] is kept current (pretty much to the day). You'll see the link for Apophis if you scroll down a little. If the odds of impact jumped by a factor of 100, this would be one of the first places to show it.

Re:Not peer reviewed.

[ZX3 Junglist]

Honey, Hi. It's Me. Your sense of humor. Can't we sit down and talk sometime? I'm a mess without you. Please say you miss me. I know deep down you feel the same way.

Oh, greeeaaaat.

[sammy baby]

From TFA:

The shockwaves from that would create huge tsunami waves, destroying both coastlines and inland areas, whilst creating a thick cloud of dust that would darken the skies indefinitely.

And thanks to little Nico, we now know that the likelihood of this happening is one thousand times greater than we thought.

Thanks, little buddy! You're a regular ray of sunshine.

Re:Oh, greeeaaaat.

[wizardforce]

one hundred, do you by chance work at NASA? :P

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Re:Damn him!

[jamesh]

Now lets burn down the observatory so this can never happen again!

Re:Damn him!

[Anonymous Coward]

Righhht.... sure, Lord Apathy, we believe ya....

Unix 1 - Humanity 0

[rubypossum]

And the 2038k problem solves itself, thus vindicating Ken Thompson and pessimists everywhere.

Re:Unix 1 - Humanity 0

[Dunbal]

2038 years should be enough for anybody

Either NASA was using FORTRAN again...

[Theatetus]

...or they forgot to do the metric conversion. Again.

So.....

[MadUndergrad]

What's Plan B?

Giant laser? Kinetic kill vehicles?

Nuke it from orbit?

Re:So.....

[nametaken]

Nonsense. Everyone knows that for an asteroid on a collision course with Earth you call Bruce Willis. At least he has a drill, a nuke and a fatherly love for Liv Tyler. It's very different from the kind of love I have for Liv Tyler, and makes him do heroic things like blow up killer asteroids at his own peril.

All Harrison Ford has is a stupid whip. All that's good for is killing Nazis and stealing rocks from crazy people.

And if anyone says Chuck Norris, I'm gunna scream. You call him when someone steals your Mountain Dew.

Where's the math?

[meatmanek]

I want to see the math. What miscalculation did NASA make? Did they use centimeters instead of meters? Was it a simple math error? Did they use an incorrect statistic?

Why did the kid have access to this information?

Re:Where's the math?

[Anonymous Coward]

He didn't really correct NASA. He only extended their prediction: NASA predicted, correctly, that the asteroid had a 1 in 45,000 chance of hitting the earth in 2029. Nico pointed out, also correctly, apparently, that if the asteroid missed the earth but hit a satellite in 2029, then it would have a 1 in 450 chance of hitting the earth in 2036.

Re:

[evanbd]

I want to see the math. What miscalculation did NASA make? Did they use centimeters instead of meters? Was it a simple math error? Did they use an incorrect statistic? Why did the kid have access to this information?

Why wouldn't he have access to the info? Scientific data gets published. You know, so that other people can read it and check the results. And correct them if they're wrong. Like in this case (though as others have pointed out, it may be less of a correction and more of a clarification).

Re:Where's the math?

[dave1791]

IIRC - The last PISA study put Germany and the US next to each other in the math rankings - i.e. neither had any reason to brag.

Interestingly, this caused shock in Germany as Germans had regarded themselves as having one of the best education systems in the world. In the US, people are so used to the idea of having a shitty education system that it passed without notice.

Re:Where's the math?

[fmarkham]

The fourth R which is no longer taught is RTFAing

Re:Where's the math?

[turkeyfish]

Even so, it would be nice to see the math. The only place I have seen such equations solved is in Feynman's Physics volumes, which unfortunately I lost to Katrina.

What is the error estimate on the precise trajectory of the asteroid and its velocity? How can they arrive at a 400 m window, when they don't even have a good tracking of all the space junk in orbit? How many satelites were taken into consideration in reaching the 1:450 number? Can these really be ignored if the trajectory is to be computed this precisely? Have all the calculations taken into account numerical precision associated with floating point representation? Have the gravitational effects of the other planets been adequately accounted for? With what precision?

Just questions it would be interesting to look at to assess how these figures are arrived at.
It wouold be instructive to see what figures NASA or the German schoolboy used in their equations.

So if it does hit a sat will we know about it?

[QuantumG]

And how long will it take to figure out if we're boned? 2 years? That leaves about 5 years to do something about it.. or, ya know, go on a long killing spree.

Re:So if it does hit a sat will we know about it?

[Anonymous Coward]

And how long will it take to figure out if we're boned? 2 years? That leaves about 5 years to do something about it.. or, ya know, go on a long killing spree.

That's the depressing part.

To answer your question: Probably a few months after the 2027 encounter (and hypothetical collision with the satellite), but at that point, it'll be impossible to do anything about it in the 9 years between 2027 and 2036.

The right strategy is to use the 20 years between now and 2027 to build an orbiter/lander (with a big-ass nuke, nuclear reactor powering a big-ass laser, or big-ass solar sail of reflective/absorptive paint -- and as much as I like nukes, the big can of paint's probably the best way to go -- attached).

We use the 20 years to build the orbiter/lander. We send it up to rendezvous or orbit in 2027. If Apophis smacks into a satellite (or we're just unlucky), we'll have an orbiter and countermeasures in orbit around the asteroid on that pass, and those countermeasures will have nine years in which to do their work. A nuke's pretty cool, but it can't compete with nine years of momentum transfer from the sun shining on a rock painted white on one side and black on the other side.

Suppose we cut it short and by 2027 we still don't have any good countermeasures - just a crappy-ass nuke as a last-ditch measure. Even if we go this route, we've still got 9 years for this orbiter to give us an exact gravity map of this object, and we'll have a couple of years after that to figure out where to land the nuke for maximum trajectory deflection away from the earth. (Hell, if we get the orbiter up there early enough in 2027, we can blow the nuke at/near closest approach to Earth and guarantee a miss in 2036!)

But we're short-sighted. So we'll do nothing between now and 2027. And odds are it'll sail on by in 2027 and we'll conclude that the odds of an impact in 2036 are only one in a few tens of thousands. But what an irony -- if we're wrong, then it'll be too late in 2028 for us to send anything to catch up to the rock and do anything about it. For the sake of a month's pork-barrel spending in Iraq, we'll condemn a few billion of our fellow humans to certain death in 2036.

If it's not Apophis, it'll be some other rock in the next few centuries. Just like the dinosaurs, we'll go extinct because we don't have a space programme. Unlike the dinosaurs, this time around, we'll deserve it.

Re:So if it does hit a sat will we know about it?

[GigaplexNZ]

For the sake of a month's pork-barrel spending in Iraq, we'll condemn a few billion of our fellow humans to certain death in 2036.

Or, you know, some of the remaining few billion of the fellow humans might come up with their own countermeasures. It doesn't necessarily have to be America.

Dang

[mandolin]

I hope that kid won the science competition he was in!

"... and for my science project, I proved NASA wrong and made a discovery of potentially epic proportions..."

Kindof tough to follow that one.

No, he didn't win

[hweimer]

First of all, the competition is "Jugend forscht [wikipedia.org]", which is the largest science competition in Germany. It consists of three stages: first there is a regional competition with winners advancing to the state finals. The winners of the state finals then advance to the federal finals, which is the last round. Roughly speaking, in every round one winner (or winning team) is chosen by a jury in each discipline (mathematics, physics, chemistry, ...).

It seems that the kid won the regional competition [tagesspiegel.de], but failed to advance in the state finals [jugend-forscht.de].

there's no way this is true

[YesIAmAScript]

A 1 in 450 chance that this thing will hit an asteroid in the way that makes it MORE likely to hit Earth?

Hitting anything in space is like hitting a needle in a haystack. Actually, that's vastly understating it.

There better be an explanation of exactly what it is going to hit and how it will "improve" its trajectory.

Re:there's no way this is true

[Fractal Dice]

seriously ... BS detector is flashing red on this whole article.

But it does raise the point that apocalypse cults are best kept away from space tech.

Re:there's no way this is true

[enoz]

It appears we have a 200 billion tonne asteroid [google.com] in a possible collision against a satellite weighing between 200KG and several tonnes [wikipedia.org]

I'd say it's more like the haystack hitting the needle.

Hang on ...

[attonitus]

... it will create a ball of iron and iridium 320 metres (1049 feet) wide and weighing 200 billion tonnes ...

If this thing weighs 200 billion tonnes, it seems surprising that hitting a satellite is going to divert its course very significantly (unless that satellite is the moon). And:

NASA and Marquardt agree that ... [it] will crash into the Atlantic ocean

Ah, so there's only a 1 in 450 chance of it hitting earth, but we know which ocean it will land in if it does (7 years after it hits the satellite).

Next week: 13 year old boy discovers new chemical reaction in which a combination of scientifically illiterate PR bunnies and sub-editors produces large quantities of bullshit.

Re:

[evanbd]

NASA and Marquardt agree that ... [it] will crash into the Atlantic ocean

Ah, so there's only a 1 in 450 chance of it hitting earth, but we know which ocean it will land in if it does (7 years after it hits the satellite).

Yes, actually, that's the easy part. We know very precisely when and from what direction it will be coming, the question is will it go left, right, or straight down the middle? (Metaphorically speaking... I don't know the details, for all I know we're above and to the left of the center track.)

Once you know when and what direction, you know which hemisphere. Once you account for projection distortion, that puts the odds as pretty good it lands in an area well less than half of the Earth's surface. S

Re:Hang on ...

[attonitus]

Right, but the asteroid has hit a satellite between now and then, a satellite which has, apparently, increased its chance of hitting earth from 1 in 45000 to 1 in 450, which means that its trajectory has changed fairly significantly. In particular, its orbital period has probably changed, which makes it seem unlikely that we can say anything accurate about an impact time 7 years later. There's only a four hour window to hit the Atlantic.

Not only that, but the Atlantic only covers one fifth [wikipedia.org] of the earth's surface, which means that even if, despite all the uncertainty, we knew exactly what time it would hit the earth, the Atlantic would cover at most about one half of the target. So I very much doubt that anyone who knows what they are doing would be prepared to "agree" that it will hit the Atlantic.

So I smell bullshit in the science lab. To be fair, it's possible that a bad translation from the original German article was required as a catalyst.

Re:

[evanbd]

The satellite would weigh a few tons. The asteroid weighs 21 million tons. The course change won't be that significant. Which is exactly why it's an interesting case -- if the course change was significant, it would miss us by rather a lot. Remember, small changes get magnified by close interactions with other bodies. So a small change while deep in Earth's gravity well changes the exact location it will be in by rather a lot some time later.

As for the Atlantic, don't forget projection distortions --

Re:Hang on ...

[attonitus]

Yeah, even with the distortion, it's still no better than about 50% to hit the Atlantic (5 time zones = 75 degrees. sin(75/2) = 0.53).

As for the small change, the asteroid is actually ~20 billion tonnes, so its about 5E9 times more massive than a satellite. There is info about its orbit in this table [nasa.gov] correctly. I haven't done the calculations, but my guess is that the ratio of its mazimum possible collision velocity relative to a typical geostationary satellite to its orbital velocity is very small, but lets say 5% (almost certainly a huge over-estimate). That means that the effect of the collision on its orbital velocity is going to be on the order of 1E-11. Now, that's well inside the the errors on the table, so yes, small changes can be amplified, but a change that is significantly smaller than measurement error is not going to change any predictions for where this thing ends up.

Re:Hang on ...

[evanbd]

The NASA NEO [nasa.gov] site gives 2.1E10 kg, or 2.1E7 tons -- 21M tons, unless I've screwed up the units somewhere or that site is wrong (both possible :) ).

The same site gives vImpact for Apophis at 12.59km/s. I haven't looked at the approach trajectory in detail, but geosynchronous orbit is only 3.07 km/s, so the relative velocity is dominated by Apophis (moving at less than 12.59, but more than the 5.87 km/s vInfinity; I'm too lazy to work out the exact number). It's orbital velocity wrt the Sun is about the same as Earth's, or 30 km/s -- so the 5-10 km/s collision velocity is 15-30% of its orbital velocity, roughly.

It's a small effect, to be sure, but it has a very, very long lever to work with. I'd be reluctant to say he's wrong without actually doing the math myself in far greater detail than either of us has done here.

Re:

[evanbd]

Yeah, it's clearly typical science journalism. For now, though I'm willing to believe there might be something there. I'd like to see an official NASA report on the story.

Of course, no one's mentioned that we'll know much more precisely what will happen by 2029 -- not only whether there's a concern at all, but which satellite would be hit. In which case we could, you know, move the satellite. The do have some station-keeping capability, after all. And even the dead ones could be moved by a tug, given

Obligatory...

[bennomatic]

I for one welcome our new German asteroid overlords.

DOUBLE OH-NOES!!!

[Plazmid]

OH-NOES! Kurzweil predicted that sometime in the 2030s computers will be able to match human brains. Combined with this recent news, this means we have to worry about killer robot overlords AND killer asteroids ending the world! OH-NOES!

Comment removed

[account_deleted]

Comment removed based on user account deletion

I want to see NASA's acknowledgement he is right

[MarkLR]

This does not sound right. The article states that Apophis has a mass of 200 billion tonnes. How would colliding with a satellite which except for the ISS max out at about 20 tonnes do anything at all to Apophis' orbit? Forget the link to the wire story where is a link to NASA statement that the impact chance is really 1 in 450?

Re:I want to see NASA's acknowledgement he is righ

[Nyeerrmm]

Thinking about the problem for a second, I can see how you can make some rough calculations. Generally any GEO, HEO, etc. type orbit will be fairly slow, especially compared to the hyperbolic orbit that the asteroid will be entering at (in the Earth's reference). Thus based on the range of velocities and masses you could predict a range of possible perturbations to the orbit.

Though I don't have any numbers to back it up right now, a small perturbation in the velocity can propagate forward to be a very large error after 7 years. Thats why we have so much trouble predicting whether or not it will hit us; a 10 meter error in its position or a 1 m/s error in velocity measurements translates into multiple Earth radii over a few years. So combine the small change in velocity from an impact with the gravitational slingshot from the 2029 close approach, and it may be enough to shift the keyhole.

Of course I think the article is misleading, it may be more like there's a 1/450 chance of some kind of impact that will have an unknown effect on the orbit but may shift it into an impact trajectory, or something like that. At any rate, there are still other unknowns such as the effect of solar wind that can vary the trajectory dramatically too.

Note of course that I could be completely wrong, although I do plan to attempt some simulations now, since one of my advisors classes is working on a related project.

Original article

[ulash]

Here is the original article [www.bild.de], in German, from the German newspaper. It looks like a professor helped him (Professor Spahn from Potsdam University). Bild is semi-infamous in Europe for sensationalizing stories but at least we know that the boy is real if nothing else...

Um, was this by any chance an April Fools paper?

[TheMohel]

Let's see. We begin with the original source of data, "telescopic observations." Good, but perhaps a bit, shall we say, lacking in nine-digit precision. Then we add the element of a bright schoolboy (always a favorite in the papers) doing something big and being validated (instantly!) by "NASA" (not a person, but apparently the entire agency). Oh, and "NASA" told "ESA", but we still don't have the identity of anyone other than the putative schoolboy.

So far, doing well.

Then we hit the big problems. First, we have the scare factor of "40,000" satellites surrounding Earth. Most of which, actually, are in LEO, with a few more in geosynchronous orbit. Which makes the space around the Earth only about 99.999% empty space, rather than a few more nines. As it turns out, space is big.

But it sounds good to imply that somehow there's this asteroid belt around the earth, and that the "killer" asteroid might hit a satellite.

Well, WHICH ONE? They have a lot of different masses, they are going in different directions, and we pretty much have to get a specific momentum change in the right direction in order to get just the right perturbation. Hitting a small piece of space junk is one thing, but the variation in weight of those "40,000" satellites is orders of magnitude. And that makes a big difference in orbital perturbation, even if the difference in orbital velocity is small compared to the velocity of the asteroid. We're talking about a subtle effect here.

And let's not figure in things like elastic collisions, off-center collisions, pieces flying off, or anything else. Nope, it's gonna happen perfectly, just like that seven-ball four-cushion bank shot we all can hit again and again.

Heck, they even called the pocket. Right into the Atlantic, after an orbit measuring in the decades. Now I will grant that the orbit is pretty well known, but again, that little "satellite assist" must be just precise as heck.

A nice touch gives us the "destroy both coasts and darken the world indefinitely." While it's good to be so certain, couldn't they be more specific about the method of destruction? Seeing as how they apparently know everything else, and all.

And finally, we have the 450:1 odds. Not 500:1, and certainly not 1000:1, but exactly 450. Cool. About as believable as my old homework excuses, but infinitely cooler. Can you say "significant figures"? I knew you could.

I think it's what you get when you let AFP (my source of news of the world for sure) loose in spring.

Re:Um, was this by any chance an April Fools paper

[evanbd]

Collisions in space are actually quite predictable. The asteroid is huge and fast, so the entire satellite gets obliterated -- no random debris falling off, because odds are that the satellite is either entirely within the path or entirely outside it. Supersonic (relative to speed of sound in asteroid / satellite, not something irrelevant like Earth's atmosphere) collisions are basically completely inelastic (details more complex, but reasonably well understood).

Satellites don't vary in mass all that much. The big ones are a few tons to a few tens of tons, once you ignore the ISS. The little ones don't matter, so you ignore them.

Telescope observations can most definitely produce the many nines of precision needed for this work. It goes something like this: on day one, it's within this error bar. On day two, within that error bar. On day a few thousand, this other error bar. Individually, the error bar is large, but as they spread out, the path through every one of them gets rather precisely defined. Imagine positioning a set of 1 meter wide gates across the US -- sure, you can't measure the position of the bowling ball you rolled through them to better than 1 meter at any one point, but by the time it's gone through *all* of them, you have sub-ppm accuracy on its exact angle. Extend the scale a bit and you get the precision needed.

Calling the pocket is the easy part: if it hits, then the piece of the Earth pointed in that direction will be the Atlantic. Sure, it might strike a glancing blow and hit at the edge, but thanks to foreshortening the odds are against that.

Re:Um, was this by any chance an April Fools paper

[TheMohel]

Sadly, I actually used your cogent comments to waste a fair bit of time and go look at the original press paper (in German, it's at this link [www.pnn.de]). It's a story of an intrepid science fair paper. Let's hear the Google translation:

Perhaps the most "exciting moment in human history", as Nico Marquardt promises Completes had chosen on Friday, 13 April 2029 at 22:45 am Central European Time. Then flies from the iron and Iridium existing space-potato, 320 metres in diameter and 200 billion tons, only 32500 kilometres of the earth over.

There, I hope that gave you a flavor. BTW, there is no mention here either of any named individual in NASA or ESA that is standing behind the numbers quoted.

The article is breathless about how wonderfully catastrophic this all is, but I do have some questions about the math. For one, are there really 40,000 satellites in geostationary orbit (or geosynchronous orbit)? That's the quoted number - I was under the impression that there were rather fewer. And how on earth do they get a figure of 1:450 that the satellite will hit one of them? And that that hit will guarantee the catastrophic outcome they so desire?

For another, I'm not getting a picture of a long observational period and multiple telescopes. Only one telescope is mentioned, and the science fair aspect makes it more suspicious. It looks more like a novel hypothesis ("what if it rams a satellite?") combined with some serious guesswork.

And finally, did anybody else get a little bothered by the description of a 160-meter radius asteroid that weighs 200 billion tons? That gives a density of a little under 12 kilograms per cubic centimeter, which would make it a rather unique and valuable material. As near as I can tell, Wikipedia being your friend and all, they missed by three orders of magnitude. Speaking of correcting the numbers...

Re:Um, was this by any chance an April Fools paper

[PatrickThomson]

As it turns out, space is big

You may think it's a long way down the road to the chemist's, but that's just peanuts to space.

In other news...

[kpainter]

NASA has plan to deal with killer satellite by 2054.

Hollywood

[Eth1csGrad1ent]

And now Hollywood can turn the German boy into an American boy, chuck the complex math for a backyard telescope, name the asteriod after the boy, throw in a baby to add drama and get Morgan Freeman to play the President... Oh wait... ...never mind.

That's it...

[FoolsGold]

We're all gonna die!

I bet by the time 2036 hits, stats will how it's now without a doubt, the year of Linux on the desktop. But it won't matter cos we'll be dead. Wouldn't that be a kick in the balls.

At least we don't have to worry

[The Bender]

Well, think on the bright side.
At least we don't have to worry about fixing the 2038 UNIX 32-bit date bug [wikipedia.org] any more.

Darn!

[fluffykitty1234]

And I just read Duke Nukem Forever is slated to ship in 2037. :(

This makes the physicist in me cry

[TiberSeptm]

I'd love to see the computer-cluster this kid calculated the 100k+ iterations of the many-bodied system of time-retarded lagrangians required to solve something like this. His parents power bill has to be insane. Considering uncertainties involved in orbital trajectories and timing for asteroids like this, 100k might even be a low number of runs for something like this. The number of satellites in orbit, their varying masses, uncertainty in the current un-colided trajectory, etc. can't possibly create a situation where you have improved odds of impact anyways. There is actually a greater solid angle of impact for collisions that would decrease the likelihood of eventual earth impact than increase it. Maybe these odds are after the most favorable possible satellite impact plus the help of magical space faries?

Apophis is an opportunity, not a threat

[damburger]

We are developing several strategies to deflect the course of asteroids. If these mature over the next few years before our close encounters with Apophis, we may have the chance of bringing into Earth orbit, providing nearby and easily accessible resources for space construction.

Providing it with enough energy to slow from solar orbit to Earth orbit could be tricky, so I suggest the best way is to deflected in such a way it undergoes aerocapture.

People always seem concerned about the possibility of the rock just smacking into Earth, and think this is a reason not to pursue such a strategy. Tell me, am I being too Lex Luthor about this?

Correction: Source wrong

[Peregr1n]

Sorry to burst the balloon, but apart from the one German article that was picked up by AFP, there's no source for this story. And NASA and the ESA deny ever saying that the schoolboy was right. It seems that the schoolboy's sums were wrong, and NASA's original workings are right. More info: http://www.theregister.co.uk/2008/04/16/esa_german_schoolboy_apophis_denial/ [theregister.co.uk] I'd file this under 'web hoax' or 'lazy journalists pick up on anything sensational'

The News is wrong

[phoenix_nz]

Just in case anyone still believes we'll all be killed by an asteroid in 2029 or 2036, here's an article from El Reg, claiming that the boy got it all wrong.
I guess we'll have to live with the miniscule 1 in 45,000 chance.

link to article:
http://www.theregister.co.uk/2008/04/16/esa_german_schoolboy_apophis_denial/ [theregister.co.uk]

Schoolboy's asteroid-strike sums are wrong

[RKBA]

Schoolboy's asteroid-strike sums are wrong [theregister.co.uk]

There's only one problem with the story: the kid's sums are in fact wrong, NASA's are right, and the ESA swear blind they never said any different. An ESA spokesman in Germany told the Reg this morning: "A small boy did do these calculations, but he made a mistake... NASA's figures are correct." It would appear that the intial article in the Potsdamer Neueste Nachrichten, which says that NASA and the ESA endorsed Nico Marquardt's calculations, was incorrect. The story was picked up by German tabloids and the AFP news wire, and is now all over the internet.

"Not entirely accurate"

[mehtajr]

So in Slashdot's world "not entirely accurate" is the same thing as "completely, utterly, bloody false." Good to know.

Re:In other news...

[QuantumG]

fallout shelters won't help.

It would interesting if funding in SpaceX and the other alt-space companies went up as a result of this.

Rich people: get us off this rock.

Re:Damn zeros

[kcbanner]

I guess NASA was using MS Excel to do their calculations.

Re:Damn zeros

[snl2587]

I guess NASA was using MS Excel to do their calculations.

Or faced political pressure to predict something other than a fairly decent chance of doom. I mean really: does anyone think a 13-year-old outsmarted every scientist at NASA?

Re:That can't be right

[snl2587]

Political pressure tends to be pro impending doom these days.

Err...yes, I would agree with that sentiment, but I think that's exactly why they wouldn't predict doom.

Bear with me for a moment (and feel free to rip the argument apart later): if NASA predicted impeding doom from the asteroid then people would panic and NASA would receive tons of funding, but for all the wrong reasons. Instead of attempting to focus on research and possible Mars visits they would be forced to spend tons of time and effort trying to avert an Armageddon that would likely never come. This would most likely set the program years back.

If they instead ignored the thing until it was certain to collide with the Earth, then they would have several years to find a relatively easy solution, and up until that point they would have twenty years of advances under their belt.

Maybe this is the lack of sleep combined with hours of work and six cups of coffee talking, but I think that NASA had/has very good reasons for keeping this thing quiet.

Exactly right

[EmbeddedJanitor]

Perhaps you were really gunning for a funny.

Once you're below a certain threshold, a few more zeros really does not change anything. Very unlikely vs extremely unlikely is hardly relevant. Increasing my chances of being hit by an asteroid by 500 times still does not put it on the radar. Increasing my chance of a car crash by 50% is much more important.

Re:No suprise here...

[Anonymous Coward]

And this observation is applicable for exactly what reason? Are you claiming that NASA management is screwing up the calculations? Or are you just talking out of your ass and trying to insinuate that NASA is always incompetent in whatever it does?

Btw, in case you are not aware, the NEO office is at JPL--not JSC. And JPL is run by Caltech for NASA--not directly by NASA.

Now that we have that cleared up you should feel free to continue your bullshitting and insinuating via hearsay.

Re:No suprise here...

[menkhaura]

NASA is a big organization. Perhaps he's trying to insinuate that NASA is sometimes incompetent at some things it does (imperial vs. metric anyone?) I'm about as unamerican as any other non-USian citizen out there, but I've dealt with big organizations, government or otherwise before,and I've seen my share of corporate stupidity and employee stupidity, which may be not even this case, because, as big as NASA is, they don't cater for the underachieving.

Re:

[rednaxel]

Who is John Galt?

Re:Not Math Error

[JLF65]

They didn't forget about them. There is almost no chance a satellite will be struck. If you read the original FA, you'd see that a) the asteroid will pass inside the orbit of them, b) it will pass at a 40 degree angle to them, and c) when the satellite does reach the distance the satellites orbit at, it'll be well beyond the region the satellites are in.

The kid calculated the odds of the asteroid hitting the earth IF the asteroid hit a satellite JUST PERFECTLY. The odds of the asteroid hitting a satellite, much less just right for that to occur, are remote at best. This is just media hype to increase ratings.