Schoolboy's asteroid-strike sums are wrong

Widespread media reports claim that a German schoolboy has recalculated the likelihood of a deadly planet-smasher asteroid hitting the Earth, and found the catastrophe is enormously more likely than NASA thought. The boy's sums were said to have been checked by both NASA and the European Space Agency (ESA), and found to be …

[Neil Barnes]

So that's why they showed...

'Meteor' on the box this weekend - just preparing us...

"So, if you were to hypothetically design such a thing, how many megatons of nukes would it have?"

[The Other Graham]

Apophis...

I for one welcome our new Goa'uld Overlord.

(even if he's not getting here for another 20 years, those motherships aren't as fast as they used to be).

[Kenny Millar]

Spoilsport

Here was me thinking how nice it would be to switch of the TV and have a few nights out watching a chain reaction as one satellite spins out of control into the next and so on....hopefully the first to go would be the Astra sats so loved by BSKYB.

My left arm is already in...

[Neil]

Just in case....

Let's put Bruce Willis on Standby...

[Anonymous Coward]

"asteroid-busting space nukes"

Huh? Anyone knows that's not how you deal with asteroids. You fly around in a little ship and shoot them with lasers, and they break up into two pieces half the size and twice the speed, which you shoot, which break up into four pieces a quarter the size and four times the speed, which you shoot... hey, watch out for that flying saucer! Quick! Hyperspace!

<ka-zott!>

[Anonymous Coward]

But...

Forgive me if I am not understanding the article correctly, but the kid is quoted as saying that *if* the asteroid hits something in orbit then the odds of hitting the earth are drastically increased, but the argument is that it wont hit something in orbit therefore he is wrong?

[Anton Ivanov]

Everybody's sums are wrong

WTF is the satellite density in that orbit in 2029? From there on all computation is kind'a bogus.

Me coat. The one with the "Energia" logo on the back.

[Christoph]

Collision with a satellite?

If the asteroid is light enough to be thrown into a completely different orbit by collision with a satellite, it is not much of a threat!

[Anonymous Coward]

Time to dig out...

...the old arcade game Asteroids and get some practise in.

[Geoff Mackenzie]

It'll hit us in 2036

Just in time for epoch time to overflow a long int.

[Anonymous Coward]

Great, We are screwed........

I heard the chances of getting 4 number in the lottery are 1 in 420, I have been lucky enough to get these odds 3 times over the years. Its doesnt sounds like good news the revised figure of 1 in 450 of a huge lump of rock landing on our planet when you really think about it!!!!!!!!!!!!

[Greg]

2029, eh?

So just as we win the war against the machines and destroy SkyNET's core under Cheyenne Mountain, this sucker comes and wipes out the last of us anyway?

</Terminator Nerd>

[Terry]

Repent - for the end of the world is nigh

So, we get wiped out in 2036 - who cares? The world's going to end when the time_t's wrap in 2038 anyway.

[Anonymous Coward]

Heh...

Vorsprung durch Technik?

[Anonymous Coward]

Oh No !

Its the end of the world folks but if you are lucky you may be able to hitch a ride on a passing Vogon ship

Get your coats and thanks for all the fish !

[Rob Elliott]

Surface to Space Missiles

Hmmm... so thats why the Americans were so keen to show they can shoot things out of space the other month...

[TeeCee]

Satellite collision.

It says here that it's about 350m across and has an estimated mass of 4.6 x 10^10 kilos (i.e. you'd be pretty certain to notice if someone dropped it on your foot).

If *that* can be deflected by a collision with a satellite, we don't need Bruce Willis to deal with asteroid threats. Just getting the majority of the population of the Earth to shout in the right direction using harsh language should break 'em up nicely.

[Eddie]

Okay, I'm not a rocket scientist...

...but not all Geosynchronous orbits are geostationary orbits..

Geostationary orbits go round the equator, but geosychronous orbits can be inclined to the plane of the equator, by considerably more than 40degrees, so unless I'm very wrong with my interpretation of "passing outside the equatorial geosynchronous zone" - this only refers to the singular Geostationary orbit, not the plethora of north-south oscillating geosynchronous orbits....

But I suspect NASA do know what they're talking about....I hope..

[cor]

And there's me worrying about me mortgage

When what I really needed was a towel.

Bathrobe donned, Vogon ship boarded.

[Turgut Kalfaoglu]

helmet day

It's still a good idea to put on your helmet that day :)

[Alastair McKinstry]

satellites

Satellite density: Methinks 40,000 is the number of objects that US SpaceWatch tracks. This includes bits of boosters and dead satellites and garbage, not just active spysats, etc.

[Bad Beaver]

@ Christoph

The info on Wikipedia says it's a 270m object of maybe 2.6×10(10) kg moving at 30.73 km/s, with an impact energy of 1480 megatons, and if it hits we likely loose bits of Russia, Mexico or its periphery with an estimated 10 million casualties should Colombia or Venezuela buy it. It's a genuine bad MoFo.

I also think the satellites won't be a relevant part of the problem by any measure.

[Anonymous Coward]

Coincidence?

Isn't the time period of the asteroid's closest approach dangerously close to the years that many prophecies predict the world will end?

[Steve]

wellll....

According to NASA: "Changing the amount of energy Apophis absorbs by half a percent as late as 2018 - for example by covering a 40 x 40 meter (130 x 130 foot) patch with lightweight reflective materials (an 8 kg payload) - can change its position in 2036 by a minimum of one Earth radius."

2036 is two sunspot cycles away. Are they really sure that the natural variation of the Sun over that time is less than the effect of a 1600m² shiny patch?

[Geoff Webber]

CO2 emissions

Hopefully by the time we reach 2028/29 China, India and the USA etc will have produced so much CO2 that the critter will just bounce off and disappear in to the ether.

so between now and then I'm going to leave the car in the drive with then engine running and turn up the central heating - just to do my bit you understand!

[Jon]

lottery

"I heard the chances of getting 4 number in the lottery are 1 in 420"

and how many lines over the years did you play in the lottery. The lottery has been going over ten years so lets say in that time you brought about 520 lines. therfore you have a 520 in 420 chance of winning. three times in ten years is 520 in 1260 or approximately 2/5

[Anonymous Coward]

doesn't take much to change things quite a lot.

You don't need to change the speed of it very much for it to add up over 7 years to make a difference.

Given conservation of momentum, and assuming the asteroid accelerates the satellite up to the same speed as itself, one would expect the asteroid to lose at least something like 1/(1*10^7) of it's speed, or about 3mm per second, for each satellite that it hit. Over seven years, that changes where it is by about 700km, more or less.

[Richard]

Excellent news ...

The world ends just in time for my retirement ! ... oh well just enough time to sell all my worldly goods and take the wife off on a long holiday on the proceedings. If it does not strike then I'll live off the backs of all these youngsters ... either way I'm not really bothered, its more dangerous on the drive home this evening.

[James Bassett]

@Bad Beaver

"we likely loose bits of Russia, Mexico or its periphery with an estimated 10 million casualties should Colombia or Venezuela buy it"

Oh right. Nowhere near where I live then. God, you had me worried there for a while.

PS Am I the only one who clicked on the headline expecting a news story about some clever Schoolboy who'd figured out a way to do his Maths homework using a classic 70s arcade game but made a mistake? How dissappointed I was.

[Alan Fitzsimmons]

Is the German press really more inaccurate than the UK press?

Oh dear...to actually use some correct information:

Apophis will pass us at a distance of 37,400km from the center of the Earth on Friday 13th (!) April 2029, with a formal uncertainty of only 770km.

Most satellites orbit in low-Earth orbit at altitudes of 300km-2000 km. These are in no danger from the asteroid. Many of the rest are in geostationary orbits at 42,100 km from the center of the Earth. This is much further out than the pass distance of the asteroid in 2029 (see below), and so Sky subscribers can also rest easy. Overall the risk to satellites is miniscule.

It needs to pass through a particular point in space to be swung around by Earth's gravity and hit us in 2036. It either will or it won't. Hitting a satellite will not deflect it into that point.

The latest evidence is that the asteroid is smaller than this at 270m in diameter.

I don't understand the iridium as if the asteroid is an iron-nickel object similar to some meteorites we find on Earth, the iridium contained is inconsequential.

<sigh>

Aliens as they're probably sitting on Apophis in 2029 with a nice view of the Earth going past.

[Anonymous Coward]

Oh My God.....

I was so sure we were going to to splattered I've just sold my house, cashed in my pension, life insurance etc, and spent all the money on debauched week of Booze, sex and drugs.

Oh well at least I didn't waste it.

[Spleen]

Re: 12:44

Yes, it's a coincidence, as there are sufficient nutters that pretty much every given period in time is predicted to be the time of the Apocalypse by *someone*.

All fortune-telling relies on the scattergun approach - throw out enough predictions and one of them is bound to score a hit.

[Joe Stalin]

@Just in case....

What will Bruce do, scare it away by singing "under theboardwalk" at it?

[Patrick Ernst]

Bang!

So if NASA et al now saying that the asteroid will not hit because it obviously can't hit any satellites in orbit, some 20 years into the future then this means, in all likelihood, that they lied and they want us to feel warm and cosy while they get those nukes all organised.

It should theoretically be easy. 20 years to put some firing platforms into space, heavily armed with nukes. The only problem is it'll have to go to tender. The tender specifications will need to be set, clarified, reviewed, challenged, re-reviewed, awarded then the the primary supplier will go bust so they have to start again. Might be time to rent The Rocketeer from the video store to find out how a home made job works. Open source hardware project anyone?

[John Saunders]

Something missing here ...

Nary a single snide remark about how the 1 in 450 headline would sell a lot more newspapers than 1 in 45,000. What's the matter with you people? Or is this the mark of the sinister hand of the editor at work?

[Anonymous Coward]

@Coincidence

No, you're thinking of the supposed "2012 singularity". You can't even keep your superstitious jelly-brained delusional new-age disaster/conspiracy theories straight, you credulous gullible gravy-sucking buffoon, what do you think you're doing attempting to make an intelligent comment?

Looking at the quality of reasoning - or even just the ability to read and comprehend the material set out in the article - displayed in these posts, I say it's a crying shame the thing is going to miss. Bring on the next dino-killer I say, Homo S. is a dead loss.

[Andy]

Shiney Surface?

So how do you install a shiney surface on a meteor?

Wax on? Wax off? Bruce? Hollywood must have the answer!

[Tripleganger]

I say we

shoot it out of the sky, just to make sure and pass time

[Anonymous Coward]

clever

Here's what happened:

Scientist told to calculate chance of asteroid hitting the Earth...

"hmm, 1/450 ..... and the chances it'll hit if the US tries to shoot it are.... 100% + a few stray nukes will hit various heavily populated areas".

Scientist tells superiors the chances are 1/45000.

[Anonymous Coward]

Scientists Lie

Ever since we got rid of the priests, the scientists have had to fill the PR role of the priesthood.

It would seem young mr x, took into account the probability of collision with a satellite, whereas NASA may have just swept that probability to a nice clean zero.

At the end of the day, who knows what might happen, statistics cannot foretell the future, and I very much doubt anyone has done a controlled experiment on an asteroid to be able to make such a prediction.

Scientists need to go back to using terms like best guess, and rocking their heads when they say it - who would have thought that by freeing them of religious persecution they would turn into the same naysayers of truth as those they have replaced.

[Anonymous Coward]

Don't panic Mr. Mainwaring!

I think I can clear up the confusion....

Geosynchronous satellites form a ring around the Earth's equator. (There are theoretically other geosynchronous orbits but these require the satellite to remain under some form of thrust such as that from a solar sail).

At closest approach the asteroid will be closer to the Earth than this orbit so if you draw it on a piece of paper it looks like there are two points where the satellite could crash into a satellite - one approaching Earth and one leaving.

HOWEVER, the 2D view is misleading. The asteroid's orbit is inclined with respect to that of the plane of the Earth's orbit, so those crossing points actually sit above or below the plane of the geosynchronous satellites - so no risk of collision.

Even if the asteroid did crash into the Astra satellite, tragically depriving millions of Ross Kemp and the new Gladiators, it'd have about as much impact (ahem) on the rock as the one-off interaction between a hedgehog and a Mondeo.

[Dennis]

Re: CO2 emissions

No, no. C02 won't do it. We need something solid.

Soot is carbon particles. We need a lot of soot in the upper atmosphere. This will knit together to form carbon fibre. And we get a global protective jacket. Problem solved.

So, lots more coal fired power stations. And burn all the forests.

Mine's the one with smoke coming out the arms.

[Anonymous Coward]

duh

this thing is going to pass within one earth circumfrance of us, in a prediction that is for a date 21 years in the future, and no one else seems worried that a minor miscalculation, a dropped significant digit, or inaccurate measurements might result in a much higher chance of a hit... are you all stupid or something? now i'm not preaching about the apocolypse here but you might want to consider that earth has been hit hundreds of times before, and some of those hits completely destroyed the ecosystem as it was.... but hey what the hell do i know... i should probably make some kind of snide remark about a kid who was off by a factor of 100, even though he is only 13 years old and he tried to account for the very real possibility that the asteroid could be deflected in its path by an impact with a satelite, space debris, or other such thrash floating around out there... really you have all put my mind at ease, my only question is how many of you have actually undertaken the same calculation and gotten nearly as close as him?

[Graham Bartlett]

What would a collision with a satellite do?

Mass of heaviest manmade satellite in orbit - 6500kg. Mass of asteroid - 2.6x10^10kg. So 4 million times heavier.

For reference, a top-spec Range Rover weighs around 3100kg - add passengers and luggage, and call it 4000kg. A sugarcube weighs approximately 1g.

Who thinks that throwing a sugarcube at a speeding Range Rover would change its direction? (If you do, I suspect your sugarcube had a little extra *something* added to it. ;-) So I think the kiddy's calculations have dropped a decimal place somewhere. In other words, he's got it wrong - and also it wasn't spotted by his science teacher, which may be a worrying report on the state of teaching in Germany.

Unless of course he was calculating the probability of it coming closer than the satellites. In which case he's still wrong - NASA are happily telling us that it *will* be closer than a geostationary satellite, so the probability is 1, not 1 in 450.

(The icon saying "may contain technical content". It doesn't, but apparently the principle of conservation of momentum is beyond some people, particularly media people. Ho hum.)

[J]

Run!

But you guys forgot that *the terrorists* will surely hit the asteroid with a hijacked space-plane (they will exist by that time, I'm sure, as will the flying cars), therefore changing the rock's orbit into 100% probable collision course! Yay, more money for the "War on Terror"(TM) and a good excuse to stay in Iraq... forever! (and maybe kill some more oil-possessing brown people in other countries too, who knows)

[Luther Blissett]

@Bad Beaver

> "if it hits we likely loose bits of Russia, Mexico or its periphery with an estimated 10 million casualties should Colombia or Venezuela buy it."

Then we walk straight in and grab the oil and/or the drugs. No messy invasions needed.

Fantastic. This is off Wiki you say?

[David Morris]

@Jon

Do you want to run those probabilities by me again? 520 in 420 chance of winning?

If this is how the calculations are being made ...

... I think that I'll start building my bunker now.

[Anonymous Coward]

Compute this...

Hmmm, NASA's computation...after the length units problem resulting in a crash on Mars and the temperature conversion problem for Enceladus ("NASA explains that the fissures are "warm along almost their entire lengths", elaborating: "These more precise new measurements reveal temperatures of at least -93°C (-135°F). That is 17°C (63°F) warmer than previously seen and 93°C (200°F) warmer than other regions of the moon. The warmest regions along the tiger stripes correspond to two of the jet locations seen in [previous] Cassini images."), I can see where they said that the kids computation was correct.

[Pyros]

@@Just in case...

Joe Stalin: "What will Bruce do, scare it away by singing "under theboardwalk" at it?"

If I was the asteroid... well, it'll be what I felt like--veer away in terror, or specifically crush Hollywood so that no other passing asteroids would hear him sing again.

[Nexox Enigma]

Re: Scientists Lie

Statistics may be used to lie quite frequently, but they play a different role in science and engineering, where they may be used quite accurately. What you see as a 1/45000 chance is just the way uncertainty is written for plebs.

"""At the end of the day, who knows what might happen, statistics cannot foretell the future, and I very much doubt anyone has done a controlled experiment on an asteroid to be able to make such a prediction."""

Statistics don't tell the future at all, and they don't even pretend to. They give odds of events, which is actually pretty useful. No controlled experiment predicts the future either - if you looked at the actual data generated from such things, you would notices uncertanties introduced from each instrument used to measure and each assumption used to control the experiment. What you get isn't a prediction, but a probability. Like a statistic.

Furthermore, nobody needs to experiment with an actual asteroid, since we know the way gravity works pretty well. An asteroid is actually a really easy problem since it happens to be in a vaccuum, which reduces all the problems of fluid flow over the thing causing drag and turbulence, which is really hard to predict for short time scales, and impossible to predict for long time scales. It would be rather easy to write a computer simulation for the trajectory of an asteroid, given enough data about it's current trajectory and trajectories of all the gravitational and light-emitting bodies. If you have that information (Which Astrophysicists know pretty well) the program is straight forward.

[Seán]

@NE

Still no tips on the horses then.

As to the topic, shame on the reg for bullying a 13yr old. A yank bashing 13yr old at that, he should be encouraged. The EU should propose allowing him [to] verify all of NASA's calculations as partial credit towards his university entrance exam. Y'know as a helpful international gesture.

[Anonymous Coward]

@duh

>"no one else seems worried that a minor miscalculation, a dropped significant digit, or inaccurate measurements might result in a much higher chance of a hit..."

That's why the calculations have been done over and over, and progressively refined over the past several years with ever-more accurate measurements of the asteroid's trajectory. The fact that the increasingly accurate results converge acts as a cross-check.

>"are you all stupid or something?"

No: /you/ are ignorant, whereas /we/ know something you don't: other people *are*, in fact, worried about the possibility of error and have been taking the correct steps to address that risk.

>"but hey what the hell do i know..."

Apparently very little, yet you still feel entitled to an opinion.

>"the very real possibility that the asteroid could be deflected in its path by an impact with"

an object weighing less than a ten-millionth of its weight? Where did you get your definition of "real" from?

[Andy]

Nobody else has said it.

R2D2 says: The chances of not being squished by an asteroid, drowned in a tsunami, or starving to death in a post-apocalyptic dust cloud in 2036 are approximately 44999 to 1

Hans Solo says: Never tell me the odds

(somebody had to)

[Steve]

Long Live El Reg

I just hope that, come 12/4/2029, we'll see a story about this in El Reg, with a hyperlink (or by then maybe a superultralink) back to this article.

And I hope that, a few months short of my 70th birthday, I'll be reading it :)

[Alan Johnson]

Tut

Schoolboy error!

[Kevin]

@David Morris

The 520/420 is more accurately described as an expected value rather than a probability. What it's saying is that is the probability of winning one game is 1/420 and you've played 520 times then your expected number of wins is 520/420 or 1.24. Which means, you're doing pretty well having won 3 times but it's not way out there.

Paris, because she always gives 124%

[Dave Morris]

@ Jon

hmm well, first off.. I'm a different David Morris than the one above who wants the bunker... anyhow the calculation of probability for getting 3 or more successful attempts at 520 lottery attempts with a probability of success of 1/420 on any given attempt is (approximately)...

1-(.29+.36+.02) = .33 ... so about 1 in 3 chance of winning 3 or more times. still not bad chances, really. Anyhow, you were not applying the addition rule (for statistics) correctly, and it is much easier to do this as a binomial distribution anyhow.

[Fuzzy]

Oops

My only hope is that the guy/girl that did the calucations for this near miss is not the same who did the calcs for the mars lander mission (Feet meters oops forgot about that).

Just in case lets put Bruce on stand by

[Scott]

@Andy

Thank you for the translation but I do believe he actually said "beep boop beep whirl squeak beep"

Unless this isn't the droid your looking for.

[Anonymous Coward]

@ Jon...

"I heard the chances of getting 4 number in the lottery are 1 in 420"

'and how many lines over the years did you play in the lottery. The lottery has been going over ten years so lets say in that time you brought about 520 lines. therfore you have a 520 in 420 chance of winning. three times in ten years is 520 in 1260 or approximately 2/5'

Um, no, that's NOT how the statistics of winning lottery numbers (or any other statistical calculation) work I'm afraid.

The calculation relates to your chance of getting any winning 4 numbers in any given draw with any given selection of 6 numbers.

While your version might seem logical, it ignores the reality of the laws of statistical probability.

[TeeCee]

Shiney surface.

That's an easy one. Just nip into your local Dodge dealer and say that you'll buy it at the sticker price and you'll take the body finish treatment with it as well.

It'll be gleaming in no time.

[Moss Icely Spaceport]

Nuke it from space

It's the only way to be sure.

[Anonymous Coward]

Brown Trousers

WTF WTF WTF I am going to be sucked of the planet's surface. AAARGH!

[Bruce Sinton]

Steve-only 70

You are more likely to be here for it than I am .

I will be 98

[Johnny FireBlade]

Conspiracy...

I reckon it's all part of a plan so NASA and the ESA don't have to look at the camera and say:

"I'm NASA and the ESA and I'm not smarter than a 10 year old!"

[Anonymous Coward]

Oops

"Who thinks that throwing a sugarcube at a speeding Range Rover would change its direction?" if it is in a zero g environment then it WOULD affect the trajectory according to Newtons laws. Surely if it passes INSIDE the Geo-stationary orbit it has to pass THROUGH it which means the possibility of a hit but would that hit cause a 90% increase of the probability of a deflection towards earth then surely it could cause a defelection away from the planet.

[Anonymous Coward]

oops

"Who thinks that throwing a sugarcube at a speeding Range Rover would change its direction?" if it is in a zero g environment then it WOULD affect the trajectory according to Newtons laws. Surely if it passes INSIDE the Geo-stationary orbit it has to pass THROUGH it which means the possibility of a hit but would that hit cause a 90% increase of the probability of a deflection towards earth then surely it could cause a defelection away from the planet.

[darren]

Chuck Norris

I vote we get Chuck to tell Apophis to sling its hook.

[Anonymous Coward]

must get used to metric......

I read it as miles which is quite large even if only 275 miles across.

[Vernon Lloyd]

Hmmmmmmm

Come on Gordon McBrown, I await NewLabours 'Meteor Tax' which will 'pay' for the technology to divert this disaster.

Meteor v New Labour. Its hard to think which one actually will cause the biggest disaster.

Paris because even she could do a better job than McBrown

[Bill Gould]

Greg - Terminator

The most recent date quoted is 2011.

Just in case I think I'll start the hoarding now and then trade my stocks of potable water, food and other necessities at highly inflated values.

C'mon man, your hawt wife/daughter for some water, porn and food... heck throw in both and I'll add medicine to the batch.

Paris, because she's used to being bartered for.

[Rick]

@Ooops

"if it is in a zero g environment then it WOULD affect the trajectory according to Newtons laws."

Sure. However, what he meant is that it won't affect the trajectory in any significant way. When you're dealing with tens of thousands and error bars of hundreds of kilometres, a few kilometres either way really don't matter.

"Surely if it passes INSIDE the Geo-stationary orbit it has to pass THROUGH it which means the possibility of a hit"

No. At its closest approach, it will be closer to the Earth than a geostationary orbit. However, at its closest approach it will be near the poles, where there aren't any geostationary sattelites. By the time it reaches the equatorial plane, it will be further away than any sattelites and therefore has zero chance of hitting anything. There is always the possibility of some random junk floating around in its path, but since any junk will be far smaller than a sattelite, the effect will be even less worth considering.

[Adam Cherrett]

Blowing up space rocks

I'm not sure that shooting it down or blowing it up (or whichever direction you shoot and/or blow stuff in zero gravity) is as easy as all that. Has anyone worked out what happens if you set off a large explosion near to a target (but not touching it) in a vacuum? Might be a fun finite-element modelling exercise. Could probably get research council funding for it, providing you demonstrate it has applications to climatology :)

[Anonymous Coward]

@@duh

did you just call me ignorant... well then let's look at a little bit of the science here...

a satelite in geo sync orbit moves approximately 3.07 km/s and as noted above somewhere, a heavy one is around 6500kg...

it may be a sugar cube, but it's moving 10 times faster than a bullet, so it has a certain amount of momentum to impart, say 19,955,000N worth of it.

that force would result in an acceleration of .00095 m/s*2, applied over say a second of impact...

hey what do you know, it would change the velocity of the damn thing by a minute amount.

hmm... let's see it has from 2029-2036 to move less than 40000 km...

could that happen..

gee such a slight tap could move it upto 209,910 km...

couple that with the fact that even the scientists of the nasa jet propulsion labs say they don't know what effect the first close pass will have on it and you start to see why i think some of the more flippant comments warrant the words "are you all stupid"

and lastly dork... if you intend to quote someone... then keep the context intact, what you did is usually called "contextomy" but you're such a bright guy i'm sure you knew that....

[Paul Donnelly]

@ Graham with his comment on the sugarcube and the Landy...

The Land Rover might well be 3 million times the mass, and a sugarcube might well just bounce off the bonnet...

But you just try putting that same 1g sugarcube into the petrol tank, and you see how much change there is to the Land Rovers speed and direction.....