37 thoughts on “A Close Asteroid Call”

    2. That is a good point but what if someone threw a rock at you, how would the 13 foot distance to where it landed influence your perception of the event?

  2. A couple of things Rand, in the interest of at least ball park accuracy. It wasn’t a ‘Tongustka’ sized rock, it was far bigger, by an order of magnitude. And I believe it is spelled Tunguska. FYI.

      1. Well it kind of does because 4179 Toutatis is probably the most extensively surveyed near earth object out there. The upcoming radar images will only build upon that already extensive database of 4179 Toutatis, a very large near Earth asteroid easily capable of continental wide civilization collapsing damage. You know, like global warming, only much quicker and precise.

    2. @Guest, December 12, 2012, 12:27 pm:
      [I]n the interest of at least ball park accuracy… I believe it is spelled Tunguska. FYI.
      I believe it is spelled “ballpark”, FYI.

    1. Even if it were half the size, if it had hit New York it would have been a hell of a lot worse than Hurricane Sandy.

  4. Human nature requires that a major city has to suffer some damage before anyone cares, and then there will be a fight over who pays for the underfunded stopgap which is rolled out.

    1. I would like to read an article from a smart and numerate science writer on the optimal annual funding for asteroid warning, with a quantified argument for why.

      Tunguska level events are *potentially* devastating, but very rare. It’s not clear to me what the actuarial benefit of identifying 90% of them ten years sooner is relative to the cost of doing so.

      1. Identifying a killer rock 20 years before it would hit is a heck of a lot more useful than identifying it ten years before it would hit. Identifying it ten years before it hits means it’s only possible to move stuff out of the way and start hardening; twenty years could be enough to move the rock out of the way.

        1. Well, yes. Short warning means you can only move the people. Who generally consider themselves much more valuable than their vulnerable real estate.

          Seriously, which deal sounds better? 24 hour warning that a Tunguska object will land on your house for $100 a year, one year warning for $36,500 a year, ten years advance warning for $365,000 a year or twenty years advance warning at twice that? More warning is better, but it’s not clear that it’s worth the cost.

          1. Good question, and it’s hard to do the math. Most of the planet is uninhabited, so the cost of your average Tunguska will be relatively small. To an order of magnitude, if you divide the total assets of the US by the total population you get about $1 million/person. A person’s life is roughly the same. So a strike that would kill 1k people would destroy a gigabuck of people and a gigabuck of property. 24 hours notice anywhere but a metropolitan area would save the people but still destroy the property. Assuming people were randomly spread out over the surface of the earth (a stupid assumption) and that property is also evenly spread (even more stupid) gives about 35 people per square mile and maybe 30k in the death zone of a Tunguska event, which gives 30 gigabucks property damage. Divide by 100 (one Tunguska a century) and you’re in the 300 megabucks a year range. A million a year for enough warning to do something about it looks like a bargain.

          2. Searching for near Earth asteroids is actually quite inexpensive. All you need are several small, automated telescopes at various locations in the northern and southern hemispheres. The scanning is automatic; they just survey the sky repeatedly each night looking for changes. Detection of movement between images can be automatic as well – a binary XOR test will identify pixels that are different between images. After that, you’d need a place to do orbital calculations (again, automatically) and forward the observations to a repository. The entire network of telescopes could be established for a few million dollars and the operations cost could be perhaps a couple million dollars a year. The greater the number of telescopes in different locations, the greater the chances of early detection.

          3. Daver:

            The math is hard. I think you are overestimating the death toll. Killing every living person within a 16 mile radius is unlikely. 30% dead is bad enough. But people in the United States seem to value their lives at several million dollars.

            On the other hand, your asset value per person seems high. I would guess that it includes the ground value of land and financial assets. The first would survive and the second is double counting.

            But these are first world values. The U.S. is less than 7% of the land area at risk. Less developed countries have less valuable property at risk, and have cheaper ways to save lives.

            Also, the most recent estimates for Tunguska events seem closer to once in a thousand years to once in a hundred.

  6. Maybe we’ll get lucky, with a slightly-smaller-than-Tunguska object (impact energy say 5kT) landing smack in the middle of Wall Street or the City of London. Warning shot and losing thousands of parasites, all in one.

    I can think of quite a few other places where a Tunguska-sized object, by landing, would improve the world.

    BTW, Tunguska was almost certainly a comet (hence the almost total lack of any trace of an impactor) and therefore the said asteroid might well have a mass equal to it, even if it’s smaller.

  9. Let’s not underestimate the value of even relatively late warning. An inbound rock first spotted two days out, with the impact point identified 24 hours from impact, could still save a huge number of lives.

  10. Meteor impact defense is fairly simple if you live in a state like AZ. First you drive out to the desert. Find a sandy area. Stick head in sand.

    Every single day we get hit by objects that explode with nuclear force but don’t reach the ground. Those are the jabs. The knockout is already on its way.

  11. How does the World Wildlife Federation or Friends of the Earth compare the risk of Global Warming to the risk of an “extinction event” related to space junk strike? For that matter, compared to the risk of a North Korean falling satellite strike?

    Isn’t the risk description plausible enough — irrespective of the actual numerical probability — that we should invoke the precatutionary principle and spend ANY amount of money necessary to prevent such a risky scenario from becoming a devastating reality?

    I personally will be taking every dollar I otherwise might have invested in Al Gore’s climate stabilization projects and re-allocating it toward force shielding the planet… And I encourage all non-anti-scientific people to do likewise. Michael Mann, are you with me? Or do you DENY the very real risk of doing nothing about this imminent catastrophe?

  12. How well can we even predict the strike zone of a potential impact? Would it be better than the forcasts for falling satellites? IIRC, the last satellite scare forecasts covered a huge swath of the planet and constantly changed.

    If the same is true for an asteroid, we are not talking about evacuating a city but an entire strike zone which could span an entire country or several countries.

    1. Falling satellites are an entirely different problem, because how long it takes the atmosphere to slow them below orbital speed is hard to predict exactly. Incoming asteroids can be predicted with much more accuracy.

          1. That’s my point Thomas, they aren’t unusual at all. We get hit daily. We will get hit by an E.L.E. It’s not if, but when.

            The only question is how prepared we will be at the time. It takes decades to get prepared. The math is in our favor but will not matter if we start too late.

        2. Good thing it exploded very high in the atmosphere, as usual. Most of these are no threat to anyone on the ground, in spite of the amount of energy released. Rocks big enough to threaten people on the ground are much, much rarer.

  13. “An inbound rock first spotted two days out, with the impact point identified 24 hours from impact, could still save a huge number of lives”.

    It could save all of them. People would have to wak about 0.50 mph to escape the destruction.

    Yes, we need a numerate scientist to write a summary of the actual risk to human life for the various sizes of impactors, their probability, what percent have been discovered, and the likely evacuation and other measures that would be taken. My guess is that there’s not much risk to human life currently. The biggest ones are know, the smallest ones don’t make it through the atmosphere, and the mud-sized ones give us enough warning to evacuate.

    1. The biggest ones are not all known. E.L.E. must be diverted or the population of the planet moved. We are no where near ready. The probability is we will be mostly ready when the time comes. It would be really sad if we could have been but were not.

  14. DougSpace – The nightmare scenario is a really big rock or dirty snowball (the latter probably being worse, because a lot faster) that comes in from the blindside and is only detected far too late to do anything – or not detected at all. Given that only about 1% of the sky is being watched at all in any systematic way, so the blindside is most of the sky…

    A Dinosaur Killer would probably kill most of humanity, if allowed to hit. Sure, the risk is small – but the loss is huge if it happens. I remember seeing a calculation somewhere indicating that the chance of an average Brit being killed in some way by another Chixculub (sp?) is roughly the same as that of dying in a traffic accident, per year.

    1. A dinosaur killer asteroid killed the dinosaurs because they lacked reason, language and opposable thumbs. They were unable to build grain silos or food warehouses, or track even the biggest asteroid threats. We are not dinosaurs.

  15. Wasting money on SLS? What if it takes a rocket that big to deflect the asteroid. And don’t start with the gravity tractor nonsense either. You have to have a matching trajectory for that–and as we have seen with Rosetta, it would takes year, decades before some objects can be reached–and that’s before the gradual tractor mission can work–which can only be helped if the spacecraft hasn’t run out of fuel first.

    A spacecraft that is SLS launched, fuel fat can do that mission more quickly and longer. Being a significant fraction of the size of the asteroid also helps. Deep Impact used a flyby trajectory, and an atomic device on a big rocket that can move farther out faster allows a solid intercept to be done more quickly than a smaller rocket which forces loop-the-loops all over the inner solar system to match an incoming impactor.

    The folks at Marshall understand this–because–unlike you–they know what they are talking about.

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