Astronomy Without A Telescope – Say No To Mass Extinction

by Steve Nerlich on March 27, 2010

Artist's impression of a gravity tug - an ecosystem saving device we haven't built yet. Credit: Durda/BBC News

You may have heard that there is an 86 per cent chance that in a mere million years or so Gliese 710 will drift close enough to the solar system to perturb the Oort cloud and perhaps send a rain of comets down into the inner solar system. 

Also, you have probably heard that there are hints of a certain periodicity in mass extinction events, perhaps linked to the solar system moving through the denser parts of the galactic disk, increasing the probability of similar close encounters. 

So, the big bad is coming… sometime. It might just be a stray asteroid that’s in the wrong place at the wrong time and have little to do with what’s happening outside the solar system. In any case, we need to stay calm and carry on – and maybe print the following handy survival tips on a fridge magnet.  

Idealised fridge magnet - for us or whoever comes next.

Immediate action: Fund sky surveys.

The Spaceguard Survey is underway aiming to identify near Earth objects down to the size of 140 meters. At present the survey might be finished in ten or fifteen years and it completely missed two small objects which are thought to have hit Earth in 2002 with impact energies approaching half a kiloton. 

Uh, anyone think we could be doing more in this space? 

Medium term action (0 – 10 years): Evacuate the area 

The 2010 National Academy of Science (NAS) report uses the strange term civil defence, but really it just means run for your life (i.e. evacuate the anticipated impact site). City destroyers in the 140 meter plus range may only hit Earth every 30,000 years or so, but it doesn’t hurt to be ready. 

Mass extinction objects in the ten kilometer range may only come every 65 million years or so. If it’s one of these… bummer. 

Long-term action (10 years plus): Call Roger Ramjet   

If we do have around 10 years notice, there’s maybe enough time to launch some of the nifty technology solutions we have at least developed on paper. Gravity tugs and mirror bees and various other deflection devices are recommended to deflect objects threatening to pass through a gravitational keyhole and shift onto a collision course next time around. 

If the object is already on collision course, no-one’s ruling out ‘instantaneous force’ (IF) options, which are either crashing something into it (‘kinetic impact’) or just nuking it – although the NAS report notes a 500% uncertainty about the possible trajectory change resulting from an IF. Ideally, a ‘full deflection campaign’ involves an IF primary deflection followed by subsequent shepherding of one or more fragments onto a safer trajectory via your preferred deflection device.

And look, if it does all goes bad at least the next order of intelligent Earthlings might dig up all these fridge magnets with mysterious symbols printed on them and be able to figure out where we went wrong. My money is on the birds. 

Recommended reading: 

The Association of Space Explorers’ International Panel (chaired by Russell ‘Rusty’ Schweickart) report. Asteroid Threats: A Call For Global Response. 

 National Research Council report. Defending Planet Earth: Near-Earth Object Surveys and Hazard Mitigation Strategies. Final Report.

Tagged as: mass extinction

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  • http://www.cheapastro.com Steve Nerlich

    Thanks for all comments… but do I detect a degree of impact denial?

    I found a old reference on the odds of dying here: http://www.livescience.com/environment/050106_odds_of_dying.html
    which puts death by asteroid somewhere between dog attack and fireworks – and about on par with tsunamis.

    I’m not sure if this analysis adequately deals with the chances of one big one killing the species – but it does show the calculated risk declines as surveillance improves.

    Cheers – S

  • Lawrence B. Crowell

    I am not sure how one can estimate the probability of death by asteroid impact. So far there are no known casualties of such. So it is difficult to know how to get a Bayesian prior estimate. Tsunamis are somewhat computable. in 2004 250,000 people died in one, which is might be used to give a prior 3.85e-5. This is close to the Livescience probability. Evidently the joint probabilities are close to unity, or a P(A|B) ~ 1/2.

    LC

  • http://home.comcast.net/~jacobsdale/AquaFarmIN.pps Aqua

    As I mentioned above.. there’s stuff going on that is just below the surface that P. Obama is privy to and the GP is unaware. Check this out: http://nextbigfuture.com/2010/03/dense-plasma-focus-dpf-fusion-systems.html

  • Aodhhan

    For someone who tosses out a lot of mathematical formulas, you don’t seem to know much about math itself.

    You don’t have to have a history of something happenening to figure out probability or risk.

    In fact, in many instances using history can throw off figures because people attempt to use common sense and/or experience instead of sticking to the numbers.

    For instance… I tossed a coin up into the air 9 times… all 9 times it came up heads. If I toss it up a 10th time, what are the odds it will come up tails? The answer… 50/50, 1:2, etc. Just as it was the first time the coin was tossed, the 3rd time it was tossed, the 4th time it was tossed…etc.

  • Phillipee

    Ok.. math lessons aside. Can someone please explain to me how it’s possible to calculate the possibility of something happening without knowing something about the history or frequency of such events?

    At this point, I almost don’t care what you say… unless you consider the frequency of asteroids colliding with the earth then your numbers are not real… there might be math that gives you that number without that data but it’s more or less made up at that point isn’t it??

  • Phillipee

    p.s. that wasn’t meant to sound condescending… just incredulous!! I have been looking into calculating probabilities and I still don’t see how you get away from making a WAG about an event at some point if you don’t know anything about it…

    I understand the coin toss example however it just seems to me as if the frequency can’t be 50/50 if you keep getting “Heads”. If you know the frequency is 50/50 how was this calculated without some knowledge of the events histories. The example is 100% “Heads” if taken on it’s own??

  • Lawrence B. Crowell

    @ Aodhhan: For a simple system such as a coin toss elementary frequentist arguments may be applied. For more complex problems one can only use a Bayesian prior probability in the Bayes rule. The Bayesian prior is not the same as a simple coin toss set of probabilities one can compute in an elementary way.

    LC

  • Hon. Salacious B. Crumb

    I hadn’t known Aodhhan was a fan of the Russell Crow film “A Beautiful Mind” and John Nash’s ideas on game theory.

    Thanks for the maths lesson, little buddy!

  • Aodhhan

    Interesting LBC.
    So set up the Bayes rule calculation you would use for a 15km asteroid striking the Earth; using 63 as the number of near Earth asteroids which meet this condition, and lets say we know 8 similar asteroids have already struck Earth. Remember.. using Bayes, the goal is to solve for the form: P(Ak | B). Good luck.

    The thing is, Bayes uses conditional probability. Meaning, you must have a history. Although, this can be used to be accurate when you have a lot of events in a short amount of time. It isn’t so accurate when there are only a few events scattered over a long amount of time. Also, one or two events can really skew the results when you have fewer events. Its like taking the average of (3, 4, 6, 2, 77, 3, 91).

    SBC…go eat another pudding pop and sit down. It’s for individuals like you, that many educators use simple and well known examples….because eventually it may just sink in. :)

  • Lawrence B. Crowell

    If you read further on up this is exactly my point. For a Bayesian prior you need data, or history if you call it that. We have a serious paucity of such with respect to computing the probability of death by asteroid impacts.

    LC

  • Hon. Salacious B. Crumb

    Aodhhan said;

    “For someone who tosses out a lot of mathematical formulas, you don’t seem to know much about math itself.”

    Kind of rude don’t you think, little buddy?

    Even if you have a point – why bother to listen?

    Very first thing about teaching is respect for others. Guess you must have missed your first class the, eh little buddy?

  • Aodhhan

    SBC… first of all.. you’re the one who chimed in with disrespect, and if this is the best you have… you’re just a waste of any educators time.

  • Aodhhan

    LBC…Why bring it up then? Especially if you can’t do anything but explain something beyond what someone can lookup.

  • Lawrence B. Crowell

    I brought it up as a question about how the estimate about expectation of death by asteroid was arrived at. Maybe not everyone who reads here is familiar with Bayesian statistics.

    LC

  • Hon. Salacious B. Crumb

    @ Aodhhan
    You seem just a little more bitter lately.
    Needless attacks on others just shows your insecurities and makes you look like a bully.
    I did read Lawrence B. Crowell opinions, and I get his point. The ‘probability’ issues you and he raise and the maths behind it are frankly irrelevant and fairly trivial.
    It is a blog site and not some very formal scientific debate after all!

    You need to grow up a bit, methinks!

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