Asteroid exploded over Indonesia weeks ago

By Phil Plait | October 27, 2009 9:24 pm

I am just now hearing about an asteroid estimated to be about 10 meters across blowing up over Indonesia on October 8. Apparently no one was injured. I have no clue how I missed this, but The Telegraph has the story. This is not an everyday occurrence, but 10 meter rocks probably do come in and explode high over the Earth’s surface every few years or so. If they’re rock they won’t make it to the ground; instead they blow up due to the incredible force of their passage through the air (in this case, the explosive yield was about 50 kilotons of TNT). Smaller rocks will rain down, though.

If it’s metal, that would be worse. It might withstand the aerodynamic pressure and hit intact. However, like I said, this is pretty rare.

The newspaper article above plays up the "What if it were just a bit bigger?" aspect, which is true enough, but what can we do? A rock or chunk of metal 30 or so meters across is dangerous, sure, but is too small to see very far out, so there’s not much we can do about it. That’s not exactly great news. It’s possible it might get spotted a day or two in advance — we’ve seen smaller ones with a day’s warning — but most likely our first warning would be the flash in the sky.

It would cost a fortune, hundreds of millions or more, to set up telescopes to scan the sky deeply and quickly enough to see all these rocks. There are some ‘scopes like that in the works, but I suspect the political will to create the network needed just isn’t there. It may take a few more impacts like the one over Indonesia before people start taking this seriously.

CATEGORIZED UNDER: Astronomy, DeathfromtheSkies!
MORE ABOUT: asteroid, Indonesia

Comments (54)

  1. Levi in NY

    So what’s the smallest rock we’ve seen coming before it actually enters the atmosphere?

  2. Is there anything we can do with today’s technology to deal with a 30m chunk of metal about to hit Earth in 12 hours beside look for a hole to crawl into and wait for loud noises?

  3. So what’s a few hundred million dollars for scopes? I’m sure they would be useful for lots of purposes, and ultimately, we’ll develop a theory of these rocks/metal bits that will allow better prediction or detection. If we are going to have the hubris to think of our species as some kind of superorganism, we might as well have the intelligence to grow giant interplanetary eyes!

  4. KurtMac

    @Levi: To the best of my knowledge, not only the smallest rock we’ve seen coming, but the ONLY rock we’ve ever seen coming from space, deduced it was a 100% chance of impact, predicted where it would impact and recovered pieces of was the few-meter wide one that came in over the Sudan in October 2008: Even then we only spotted it 20 hours before impact.

    And here you thought we we’ve been able to track a bunch of them already! Its actually an honest mistake, because we “should” be able to track these objects, and we “could” with our current knowledge and technology, its just that the people who write the checks don’t seem to “want” to take these things “seriously”. Air quotes, indeed.

  5. Sarah

    The Telegraph article: “The White House is to develop a policy on the space object impact threat by October next year.”

    What could a plan like that possibly look like?

    I hope it doesn’t entail “Space Object Impact Drills” taking up classroom time 😛

  6. Davros

    Someone should write a book about possible

    Death from the Skies

  7. Hamish

    > “It may take a few more impacts like the one over Indonesia before people start taking this seriously”

    Or perhaps only one strategically placed impact…

  8. jimspice

    A decision will have to made re: how many lives are expendable vs. how much are we willing to pay for detection/prevention. I’m sure the insurance companies have the tables prepared:

    Average meteor size X average population density / average human worth > expenditure on prevention

    Of course we could follow the Cheney Doctrine: “If there’s a 1% chance of “X” we must treat it as a certainty.”

    I can’t believe I would ever plug Cheney.

  9. jimspice

    Disclaimer: The quotation marks above do not imply a direct quotation but rather a summary.

  10. Gary Ansorge

    Let’s see: iron at 7.872 gms/cc: nickel at 8.9 gms/cc: a meteor that’s 50/50 iron/nickel, so about 8.4 gms/cc ave. density. Then let’s assume a 50 meter wide cube(cubes are a lot easier to calculate)
    so 50m on a side x 100cc= 5000cc x 5000cc x5000cc= 125,000,000,000 cc x 8.4 gms/cc= 1,050,000,000,000 gms.. Now divide that by 1,000,000 gms/tonne and we get 1,050,000 tonnes,,,um, yeah, THAT would not even slow down on entry thru earths atmosphere(I’m assuming an average Velocity of 30 km/sec). I recall an estimate that any rock at that velocity and massing over 50,000 tonnes would be relatively unslowed by earths atmosphere, so all that kinetic energy could be delivered to the surface.

    Yeah, that could really mess with somebodies day.

    According to Wiki, the Arizona impact was only the un-disintegrated half of a 300,000 tonne meteor. Original estimates were that the meteor was 50 meters across and traveling at 12.5 km/sec. That’s a mass two and a half orders of magnitude smaller than my estimate for a rock that size and it virtually vaporized on impact. So, anyone want one of THOSE in their back yard.

    Yeah! Me neither.

    I expect we could spot such a rock a few days to weeks before impact but at this stage of our space going capability there’s damn all we could do about it.

    Eyes! We need more eyes looking out there,,,and a nuclear powered,massive launch vehicle.Such as:

    Gary 7

  11. Emery Emery


    Is this article full of a little bit of crap?

    For example, what’s the difference between slightly and two to three times larger? The Meteor was 10 meter and the article said;
    …if the object had been slightly larger – 20 to 30 metres (60 to 90ft) across – it could easily have caused extensive damage and loss of life, say researchers.

    Not only are they being absurdly hyperbolic but they fail to mention the difference between a metal and rock meteor. The question that occurs to me is, would a 20 or 30 meter meteor break up if it were rock as well?

    The article also said;
    Luckily, due to the height of the explosion – estimated at between 15 and 20 km (nine to 12 miles) above sea level – no damage was caused on the ground.

    Isn’t there no luck involved at all? Isn’t that where all the objects hurdling toward earth at 45,000mph explode if indeed they are going to explode?

    Another question I have is, do we have data on rock vs. metal meteors? Is one more common than the other?

    Thanks for the heads up. Love it, as usual.

  12. Ryan

    It may take a few more impacts like the one over Indonesia before people start taking this seriously.

    Am I missing something here? Are asteroids of this size a problem for people? How many people have been killed by 10-30M asteroids? Would there be another use for telescopes capable of near earth asteroid observation? Why should that investment take priority over other astronomy research projects?

  13. Sam

    50 kilotons?!?!

    To put that in perspective, little boy was ~15 kilotons and fat man was about 21 kilotons.

  14. tacitus

    I think the only thing you can realistically do is work from the top down. A city-wide impact would be devastating locally and even nationally, of course, but we would recover from that within a few years, and even if they are much more frequent than the planet-killers, they are infrequent enough that we likely still have plenty of time before one of them comes in for a hard landing.

    So I think we’re better off looking for the big ones first and then working out way down to the smaller sizes as our technology and capabilities improve over the next few decades.

  15. MadScientist

    I disagree about what it will take for people to look out for space rocks; what it would take is a calamitous impact in a medium to high density population area, preferably a large US city because the general public wouldn’t care if all of Mexico City were obliterated by a chunk of space rock. From there we move on to the “let’s watch for them” and then techniques may eventually be refined to spot them earlier. However, because of the large populations of many cities, you can forget about evacuating an area – just think “New Orleans + Katrina”, and that is a case of a known threat with a lot of forewarning and fairly good prediction of the affected area. As for intercepting the space rocks – oh come on – we can’t even reliably intercept relatively slow and large incoming missiles (not counting automated guns which spray debris everywhere in hopes of disabling an incoming projectile – they work fairly well), so forget about catching a hypersonic projectile.

  16. a 20 metre sphere is not just slightly larger than a 10 metre one.
    It’s eight times the mass.

    I’m not worried for myself, or even the number of people that might die if such a meteorite hit my home town/county of Arlington. These things hit the Earth rarely, and inhabited places even less often.

    But if a comet or other Near Earth Object the size of the one that hit Jupiter a few years ago, mere frozen methane and water and dirt — in pieces yet — came close enough to hit Earth we’d have a real disaster, and I wish we had a whole survey set up to watch for such monsters in orbit. The thing to do about it is land something nuclear upon it while it’s on the other side of the Sun. A small nudge would suffice to change the orbit by several Earth diameters. But shattering it into a million pieces two days from impact won’t help at all.

  17. Frank

    I was thinking along Sams line- WTF! it was like a nuke went off in the sky over Indonesia. Crazy days out there lately.

  18. One other thing — a big enough solid object hitting the ground at meteorite speeds turns into a plasma before it gets stopped. Even a big enough chunk of ice would do so, because only the surface melts in the atmosphere. So you’ll get very high energy radiation, X-rays and gamma rays, from the impact site for a very short time.

  19. PlasticRectangle

    Deep Impact mission circa 2005 kinda invalidates that premise of no ability to intercept in deep space. Just a matter of switching scientific instruments for a fusion warhead and kaboom!
    Obviously it would only work on the small ones or those we find well in advance so the debris field has time to expand, but the (relative) simplicity of Newtonian mechanics makes interception of predictable rocks more trivial than enemy missiles under powered flight in an atmosphere.

    The most elegant method I’ve heard of, when they find a real big one (decades in advance hopefully) is to cover it in a white sheet or coat it in some bright powder, so sunlight’s pressure does all the work as the years go by.

  20. Rick

    Hey BA, not sure if you’re aware of this, but your RSS feed at LiveJournal is broken.

    I’m not sure if you manage that yourself, or if a fan does, but the link is:

  21. I was just hoping for a recommendation of “run.”

  22. JB of Brisbane

    Did anyone else in Australia hear about this? Let me get this straight – an asteroid becomes a meteor in Earth’s atmosphere, explodes with a bang two-and-a-half times the Nagasaki bomb over one of our near neighbour countries… and to my knowledge, not one of our newspapers or TV news services picked it up. Or was I asleep that week, meaning this is an argumentum ad ignoratum?

  23. Leanne

    is this connected to the one that hit Latvia on sunday :-))))))

  24. shawmutt

    The better way to publish this news–

    With the headline “Asteroid Impactor Reported over Indonesia”…

    Instead of a b.s. article with the headline “Asteroid explosion over Indonesia raises fears about Earth’s defences WTFLOLBBQ!!11oneone”

    Unfortunately factual news articles with actual data don’t get web clicks…

  25. T.

    The only place I saw it mentioned was on the #dps09 Twitter feeds – I presumed it was the normal conference scuttlebutt, and there’d be a press release. Which never materialised…

  26. Al C

    I can’t believe the media basically ignored this.Must have had more ‘important’ things to talk about I guess….like the so-called ‘swine flu pandemic’.

  27. Jupiter

    JB, did it have a boy missing and riding the meteor ? (I know what I wrote)
    That’s how our press is. I mean they are just people like you and me, they are paid and while some of them get paid to keep their eyes and ears open for things, things get missed, especially if they’re in a different language !

    I sure was a pretty bolide … the one that scares me is that 70s footage of the asteroid skimming through the atmosphere – that one would have hurt given that it was big enough to just keep on going !

  28. deathdie

    I believed that asteroids become our concern right now. forgive Ya Allah.

  29. #8 Jimspice:
    In the UK, our government uses these kind of risk assessment statistics to determine what to do to reduce the risk of various natural and man-made disasters. The graph of “probability of occurrence versus number of deaths if it does” is divided into three regions:
    “Negligible risk”, meaning not enough risk to justify spending public money.
    “Significant risk”, meaning something should be done to reduce the risk, as far as is economically feasible.
    “Unacceptable risk”, meaning something must be done to try to reduce the risk, irrespective of cost.
    Guess where a major ( city-buster or worse ) asteroid impact falls… well within the region of “unacceptable risk”. But what is our government, or any other, doing about it? Precisely nothing!

  30. D.Rose

    JPL seems to think the story is real and there’s video of after the explosion:

    Anyway, why does God hate Indonesia so much? Every other year some disaster seems to hit them.

  31. Brian

    Neil said:
    Guess where a major ( city-buster or worse ) asteroid impact falls… well within the region of “unacceptable risk”. But what is our government, or any other, doing about it? Precisely nothing!

    Risk calculations have to take into account the probability that an event would happen. Therefore, city-busting meteors that actually hit a city are probably in the “negligible risk” category because they are so rare.

  32. @ MadScientist:

    …preferably a large US city…

    Might I suggest New York? Specifically, Lower Manhattan?

    @ D. Rose:

    Anyway, why does God hate Indonesia so much?

    Shouldn’t that be, “why does Allah hate Indonesia so much?”

  33. Robert E

    One of the main threats of meteors that size might not be impact but the accidental spark of a nuclear conflict, because they DO look like nuclear explosions to some sensors.
    The story above deals with the meteor detonation over the Mediterranean on June 6, 2002, and US Brig Gen Simon Worden’s concerns of what might have happened if it had happened a few hours earlier — occurring over India or Pakistan, who were extremely tense at the time.

    Typing “meteor trigger nuclear war” into Google brings up a long list of articles discussing the posibility.

  34. tacitus

    @Neil Haggath: Guess where a major ( city-buster or worse ) asteroid impact falls… well within the region of “unacceptable risk”. But what is our government, or any other, doing about it? Precisely nothing!

    Is that your estimate, or the British government’s? Britain isn’t a particularly large place in relation to the whole world, and given there’s only been one single city-killing impact in the whole of recorded history (Tunguska), I’m not sure the risk does fall into that category anyway.

    Sure, if you could spend a few million pounds to eliminate the risk, they might do it, but you’re talking about spending billions on developing and deploying a technology that is almost certainly never going to be used before it is obsolete. I can only imagine what the British public would say about that!

  35. Chip

    @ PlasticRectangle wrote:
    “The most elegant method I’ve heard of, when they find a real big one (decades in advance hopefully) is to cover it in a white sheet or coat it in some bright powder, so sunlight’s pressure does all the work as the years go by.”

    That’s one. Another, more expensive way, relying on considerable engineering, would be to intercept it well in advance of impact with an unfurled gigantic screen, kilometers across that is designed to be highly stretchable. The screen in no way stops the asteroid but when it and the asteroid meet, its stretching applies force over a wide surface area changing momentum and altering course. Not unlike the loose chain-link fences sometimes seen along steep mountain roads that collect rolling boulders. If the fence were too taut, the boulder would punch through but since it stretches, it acts like a break, robbing momentum.

    More drastic than white powder and a bit crazy, (as crazy as the Barnes Wallis bouncing bombs) but perhaps doable if there is less time and the future of the human race is at stake.

  36. Noton Urlife

    The larger objects ARE tracked. Find here, near bottom of page, titled Oct. 2009 Earth-asteroid encounters:

  37. Are telescopes much use in detecting asteroids coming from the direction of the sun? Or does the sun being in the way reduce impacts from that direction? Would anything that managed to “slingshot” around the sun be a greater threat due to the increased velocity?

  38. 26. Al C Says:
    October 28th, 2009 at 4:39 am

    like the so-called ’swine flu pandemic’.

    What do you mean, “so-called?” It’s an outbreak of an infectious disease occurring in more than one location. That’s not a so-called pandemic, it is the definition of a pandemic.

    As for the 20-30 meter impact scenario, I’m having trouble seeing how the risks outweigh the costs. The odds of such an asteroid hitting land are just three in ten, given that 70% of the surface is covered in water. The odds of hitting a habitable area are one in eight. The chances of hitting an urban area are even slimmer, since only 1.5% of that 30% of land mass is urban. Add that to the infrequency of this type of asteroid strike to begin with, and the lack of any realistic mechanism to do anything about it, it seems to be that we’re better off concentrating on the planet killers rather than worrying about every little chunk of rock out there.

  39. Jon Hanford

    Any chance of locating possible meteorite samples from this fall (over land of course, similar to the recent Ontario, Canada meteorite)?. Can a reasonable impactor debris field be calculated? Any findings of smaller secondary meteorites will certainly help in the determination of the impactors’ chemical makeup.

  40. MadScientist

    @PlasticRectangle #19: That experiment involved being hit by an asteroid which had been studied extensively in the past, and obviously one large enough to be observed from the earth despite the great distances. It is still a phenomenal feat given the distance traveled for the job and it’s no mean task to correct your position in the last minutes to ensure that the impactor gets in the way, but we’re talking about space rocks which are not in a nice safe orbit and which we may not even spot until 1 or 2 days before – there is no time to plan and the analogy to trying to hit a ridiculously fast missile is still an apt one.

    But let’s say that we can hit the thing – so we send up a HUGE impactor to intercept – it can no longer steer as easily and will necessarily impact very near the earth. How heavy is the space shuttle, because that’s about the weight we can heft into low earth orbit at this point in time. It is likely that we’d need to break orbit to intercept, so the impactor would necessarily be much lighter than the shuttle. Then you need to factor in the momentum of both bodies to get some idea of what the effect of the impactor would be. Would the space rock even be broken into smaller pieces (and would that be helpful) or will the atmosphere still do the vast bulk of the work?

  41. D.Rose

    @ kuhnigget
    “@ D. Rose:
    ‘Anyway, why does God hate Indonesia so much?’
    ‘Shouldn’t that be, “why does Allah hate Indonesia so much?'”

    Er, not necessarily. “Allah” is “God” in Arabic and besides all three religions (Judaism, Christianity, and Islam worship the same god of Abraham).

  42. Cairnos

    30m asteroid, that’s tricky, not much room to land an experimental space shuttle filled with rough, quircky but good hearted oil drillers…..on the other hand not so far to drill either.

    On a more serious note:
    @19 plasticrectangle -“Just a matter of switching scientific instruments for a fusion warhead”

    Doesn’t that leave us with a cloud of radioactive debris still heading in roughly the same direction?

    What happens if a rock of sufficient size and/or density to hit the earth is struck by one or more small objects on the way down. In other words would an interceptor that worked on the ‘real big shotgun’ approach have a chance to cause it to fracture into smaller pieces which would either explode or do less damage?

  43. Ryan


    I’m not sure we would have to do much about a 10-30M asteroid. If we had a 3 day warning, we could simply move out of the way. Nothing fancy required. I agree with your assessment though, the risk is so remote that it does not justify the cost.

  44. Robert E


    We had that much warning here in the States for Hurricane Katrina, and we still weren’t able to get everyone out of the way. Why would a possible meteor strike be any different in terms of evacuation ability?

  45. Don’t get me started on Katrina. There was enough advance warning to get everyone out, but a mix of government incompetence and individual ignorance (hubris?) made the job a case study in what not to do.

    Someone asked about asteroids from the sun’s general direction. They’re one of the great unknowns in this whole game, since geometry won’t allow us to look for them often until we have an asteroid seeker in space. Only a couple have been found so far (I don’t remember the term given to them, and a quick search didn’t bring it up), but they’d come as a nasty surprise. It’s also possible that one with an apohelion (high point from the sun) right at Earth orbit’s radius would make it one of the more likely rocks to hit us.

  46. 42. D.Rose Says:
    October 28th, 2009 at 4:23 pm

    Er, not necessarily. “Allah” is “God” in Arabic

    If you want to get really technical, “lah” is “God” in Arabic. “Al-lah” is “The God,” since al- is the definite article. For followers of Abrahamic faiths, of course, the capitalized “God” implies “The God,” so it’s somewhat moot.

  47. There are patterns and cycles of asteriod contact with the earth.
    the solar system calmed down in the last hundred million years.

    I cant believe something as real a threat to our regions or the earthling entire lifeforse
    then our scientists need to stop playing god looking for heaven, and focus on a
    visual shield of
    satalites and ground based units that can give possible warning in advance
    , the continium of learning and having nobel ideas that make life wonderful but I see Less then required for the mass of human on the earth. world unity and shared science mat solve the problem. A World Agency. not a pooly funded usa labratories.

  48. I understand that our solar system is currently in a “temperate ” zone that we wobble in. When we go above or below a certain point we are subject to a lot more cosmic radiation. Does anyone know where we are currently in that cycle?

  49. ernest4

    If there had been a warning of perhaps 8 hrs prior to impact and that Indonesia was the definate impact zone how many people would have died of heart attacks,car crashes and various acts of violence due to panic in trying to escape projected impact area as compared to the actual loss free event. . Could it be possible that some government entity/security agency of at least one country was aware of this and said nothing?

  50. Darren

    Why not use radar instead of optical imaging telescopes to detect inbound threats?

  51. cita pratiwi

    I am an Indonesian but I don’t know about this news. Oh..
    thanks anyway for the writer


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