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Small Asteroid To Buzz Earth

Posted by kdawson on from the just-a-flesh-wound dept.

ddelmonte writes in to tell us about a small near-earth object, discovered just 2 days ago, that is expected to pass within 64,000 km of our planet on March 2, 13:44 UT. NEO 2009 DD45 will be well inside the Moon's orbit and just under twice the altitude of geosynchronous satellites. According to Sky and Telescope, 2009 DD45's closest approach will be over the Pacific west of Tahiti, so observers in Australia, Japan, and perhaps Hawaii will have the best chance of spotting it with, say, an 8-in. telescope. Here's where you can generate an ephemeris of the object for your location. At closest approach NEO 2009 DD45 will be moving half a degree per minute and peaking around magnitude 10.5. It will be brighter than 13th magnitude for only a few hours.

48 of 171 comments (clear)

  1. Piggy ride! by Chicken_Kickers · · Score: 5, Interesting

    Why can't we send a probe that will land on this asteroid and then piggy ride on it. That way we don't need more fuel to carry it round the solar system. If the asteroid doesn't go where we want, then have a relaunch mechanism for the probe to get off at the most suitable point in the asteroid's orbit.

    1. Re:Piggy ride! by Anonymous Coward · · Score: 4, Insightful

      You don't save any fuel by being near an asteroid. Putting the probe in the same orbit as the asteroid would have essentially the same fuel cost (actually a little less, because you would not have to overcome the escape velocity of the asteroid).

    2. Re:Piggy ride! by evanbd · · Score: 3, Insightful

      Having the asteroid there doesn't change anything, really. It costs the same amount of delta-v to put a probe on that orbit whether or not there's an asteroid (at least for tiny rocks like this; it would have to be getting toward small moon size to matter much). You already don't need propellant to carry a probe around the system -- things in space just coast, following an orbit determined by gravity. The hard part is getting it onto the right trajectory, not keeping it there.

    3. Re:Piggy ride! by amorsen · · Score: 5, Insightful

      Why can't we send a probe that will land on this asteroid and then piggy ride on it.

      "Landing" would either actually be "crashing at a speed measured in km/s" or would require just as much fuel as going in the same orbit without the asteroid, and then what's the point...

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    4. Re:Piggy ride! by CrimsonAvenger · · Score: 4, Informative

      Why can't we send a probe that will land on this asteroid and then piggy ride on it. That way we don't need more fuel to carry it round the solar system. If the asteroid doesn't go where we want, then have a relaunch mechanism for the probe to get off at the most suitable point in the asteroid's orbit.

      If we have the deltaV to land on the rock, then we have the deltaV to match its orbit without bothering to land on it. So why waste time with the landing?

      Or were you thinking that little or no deltaV would be required because the rock was passing close by?

      Well, no, a quick guesstimate based on the limited information in the article has it passing at about 9km/s relative to Earth, at 64000km altitude. Which is rather more than escape speed. About 8500 m/s over Earth escape speed, in fact. We've sent probes out faster than that a few times. The stuff that goes out past Jupiter, for instance. But it's a non-trivial exercise.

      --

      "I do not agree with what you say, but I will defend to the death your right to say it"
    5. Re:Piggy ride! by MichaelSmith · · Score: 4, Informative

      IF you land on it, it will continue to travel without fuel for propulsion for a VERY long time... that could be rather useful

      It you match speeds with it you will continue to travel without fuel for propulsion indefinitely. Being docked to a rock will make no difference. The advantage of having the rock there is that you can mine it for resources and use it as a radiation shield. You could also push transfer momentum to it if you want to change your velocity.

      --
      http://michaelsmith.id.au
    6. Re:Piggy ride! by meringuoid · · Score: 4, Informative
      Why can't we send a probe that will land on this asteroid and then piggy ride on it.

      Physics doesn't work that way.

      You seem to think it's like hopping on the back of an old London bus: grab it as it passes and jump up onto the step. But speeds in space are far greater than that. If you try to catch an asteroid as it passes, words like 'splat' or 'crunch' are appropriate. You need to match the asteroid's velocity very closely in order to land on it without being destroyed - and if you can do that, then you're on the same orbit as the asteroid anyway, and you'll go where it goes whether you land or not. So you don't actually need the asteroid to be there.

      I suppose you might arrange something cunning with a big net and a lot of bungee rope, if you can pull off an incredibly accurate flight plan, but even so it's unlikely that the asteroid is going to be near any other targets of interest in the near future; it's more worth your while to load up the extra fuel needed to fly direct to the planet or moon you want to study.

      --
      Real Daleks don't climb stairs - they level the building.
    7. Re:Piggy ride! by MurphyZero · · Score: 4, Informative

      If you could match speeds with it, you could go where it goes without need for the asteroid. Since the asteroid has no propulsion of its own, it's not providing any benefits, if you 'match' speeds (actually velocity, speed and direction). The benefit only comes in matching position and letting the asteroid change the velocity of the spacecraft to match. As long as the spacecraft survives that impact, then it can be used to provide a great momentum transfer.

      --
      Our founding fathers removed the guys in charge. Be American. Vote incumbents out.
    8. Re:Piggy ride! by pcolaman · · Score: 3, Interesting

      I vote we shoot it down, just to see if we can do it. That would be more fun, anyways. I nominate myself to push the button.

    9. Re:Piggy ride! by MrMista_B · · Score: 2, Insightful

      Well...

      Landing a probe on an asteroid passing by at this speed, would be like trying to catch a bullet with your bare hands.

      I'd say the mental imagery is pretty close to accurate, in both cases.

    10. Re:Piggy ride! by Meumeu · · Score: 2, Insightful

      Surely the asteroid has considerable inertia due to its mass? A probe would have to apply thrust to overcome gravity wells that it encounters. The asteroid will be affected by the "drag" of passing close to large bodies but already has considerable ineria.

      Let's say that I sent a ping pong ball, a house brick, and a 20t lump of iron heading away from earth at 5 m/s. I would expect the ping pong ball to slow most quickly, followed by the house brick. In some situations, the lump of iron might be able to escape where the others would not. You'd experience the same effect if you tried to stop a car rolling down hill a ten miles per hour and then compared it to stopping a skate board moving at the same speed. Perhaps I'm missing something?

      Yes, you're missing the basics of physics... This whole post is pretty much bullshit.

    11. Re:Piggy ride! by meringuoid · · Score: 3, Informative
      Let's say that I sent a ping pong ball, a house brick, and a 20t lump of iron heading away from earth at 5 m/s. I would expect the ping pong ball to slow most quickly, followed by the house brick. In some situations, the lump of iron might be able to escape where the others would not. You'd experience the same effect if you tried to stop a car rolling down hill a ten miles per hour and then compared it to stopping a skate board moving at the same speed. Perhaps I'm missing something?

      Yeah. No friction or air resistance in space, that's what you're missing. Oh, and all of physics since Galileo, you're missing that too.

      The brick has less mass than the iron lump, true - and so it has proportionately less inertia. But the gravitational force on the brick is also less than that of the iron lump, by the same proportion. The two cancel out. If they have the same velocity, then if one escapes, so does the other. It's the same principle as how a brick will fall at the same speed as a feather, if dropped in a vacuum.

      Similarly, if a spaceprobe and an asteroid fly away from the Earth at the same velocity, it doesn't matter whether they're attached or separate: both will follow the same path.

      --
      Real Daleks don't climb stairs - they level the building.
    12. Re:Piggy ride! by radtea · · Score: 2, Interesting

      Gigantic. Bungee.

      This is actually not completely insane. Just dumping some guesses at "reasonable" parameters into a dumb-as-rocks bit of Python to simulate the encounter, a bungee with a relaxed length of 1000 km and a spring constant of 10^-3 N/m would do the job with a peak acceleration of about 160 g assuming 50 km/s delta-v. Total acceleration time is about 100 seconds, and the bungee stretches out to about two and a half times its relaxed length.

      If you had a material that would stretch up to 10 times its relaxed length you could keep the peak acceleration down to about 25 g!

      These calculations assume the asteroid is much more massive than the probe--if it is not then the numbers actually get a bit better, as the asteroid slows down a bit as the probe accelerates.

      In any case, I wouldn't rule this out. Hardened instruments can take insanely high accelerations, and materials are getting more incredible all the time.

      --
      Blasphemy is a human right. Blasphemophobia kills.
    13. Re:Piggy ride! by swillden · · Score: 2, Funny

      a bungee with a relaxed length of 1000 km and a spring constant of 10^-3 N/m would do the job with a peak acceleration of about 160 g assuming 50 km/s delta-v. Total acceleration time is about 100 seconds, and the bungee stretches out to about two and a half times its relaxed length.

      :-)

      Of course, then there are the issues of getting a 1000 km bungee up there, and figuring out how to lasso the asteroid.

      --
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    14. Re:Piggy ride! by CrimsonAvenger · · Score: 2, Interesting

      With a thirty metre object you could almost snare it with a net. Then you would need a shock absorbing tether to match velocities.

      It's a 30 metre object moving well over escape velocity. You snag it with the net, and then endure 9000 gravities acceleration, and in only a tenth of a second, you've matched orbits.

      If your tether will stretch to a length of 450 metres while holding a weight (you, or a satellite your size) of about 2000 tons.

      Good luck with that.

      Given that materials for tethers are improving all the time, and that high tech space drives are not inventing themselves the way they do on star trek, I wonder if this could be a practical way to travel around the inner solar system

      In a word, no. If you want more words, "practical" doesn't begin to describe this notion.

      --

      "I do not agree with what you say, but I will defend to the death your right to say it"
    15. Re:Piggy ride! by CrimsonAvenger · · Score: 3, Informative

      Let's say that I sent a ping pong ball, a house brick, and a 20t lump of iron heading away from earth at 5 m/s. I would expect the ping pong ball to slow most quickly, followed by the house brick. In some situations, the lump of iron might be able to escape where the others would not. You'd experience the same effect if you tried to stop a car rolling down hill a ten miles per hour and then compared it to stopping a skate board moving at the same speed. Perhaps I'm missing something?

      Have you read anything by this guy Newton? Fig, or Isaac, one of the two. He pretty much explained (about 300 years ago) how this whole "gravity" thing works.

      And, for what's it's worth, 5 miles/second (I shudder to think you might have meant metres/second) is below escape velocity. It's barely above orbital velocity. So not even your lump of iron would escape. Even if gravity worked they way you think it does, as opposed to the way it really does.

      --

      "I do not agree with what you say, but I will defend to the death your right to say it"
    16. Re:Piggy ride! by retchdog · · Score: 2, Interesting

      It's not crazy at all: http://en.wikipedia.org/wiki/Project_Orion_(nuclear_propulsion)

      Compared to using pneumatic springs to harness and dampen the force of exploding atomic bombs in order to propel a manned craft, coupling to an asteroid is downright quaint.

      --
      "They were pure niggers." – Noam Chomsky
    17. Re:Piggy ride! by MichaelSmith · · Score: 2, Insightful

      Gigantic. Bungee.

      This is actually not completely insane.

      It is an insanely exciting idea. Imagine hooking on to an object like that in a small spacecraft. A few thoughts on the subject:

      • Build an unmanned probe with can outfit a small asteroid with docking hardware. It could attach itself with two loops of rugged cable. Attached too the cable would be a socket which tethers can attach themselves to. A single installation could be used for decades by different spacecraft.
      • Catch the asteroid with your tether extended. Consider the asteroid moving along +Z at 10km/s. Tether is 1000km long and the spacecraft is 1000km away from the point of capture along +X. Immdiately before capture explosives on the tether end assembly fire to accelerate the end of the tether. Magnetic and electric fields in the tether and socket may assist in a fast capture. Doing it this way eliminates sudden loads as the tether takes up slack. Instead the spacecraft is swung around (yeah at high G) and releases when it is headed in the right direction.
      • Equip vehicles with heat shields and solar sails. Both require only present day technology. Aerobraking at (say) Venus could be used for a course change.
      • Consider using angular momentum from Asteroids and free space tethers to store energy. One vehicle could sump energy into an object, another could make use of it.
      --
      http://michaelsmith.id.au
    18. Re:Piggy ride! by Hordeking · · Score: 2, Informative

      OK, OK. Looks like a made mistake on that one. Although, I did phrase my point as a question, as I'm no expert on space science. My mistake.

      I understood where you were coming from. These are common beginners' misconceptions.

      Here's how it works (you confused a few things). We have things like mass, cross-sectional area (important in slowing things down), density, etc.

      For starters, let's use your ping pong ball, brick, and iron. Furthermore, let's assume a perfect vacuum. If I fire them all at velocity v, they'll continue forever at velocity v. Mass doesn't make them slow down (but it does affect how much energy I have to expend to make them go velocity v).

      Now, let's get a little deeper as to why this is. All objects have mass (pretty much every non-quantum mechanical object in existence), which is a measure of what we call inertia. Inertia is just a fancy word that basically states that an object with mass resists changes to its motion (Newton's eponymous first law). This means point masses tend to travel in straight lines if they were already doing that. Or it could simply be stopped (it won't just spontaneously start moving for no reason). What all this means is that a ton of iron is a hell of a lot harder to stop than a 1/4oz ping pong ball. (Newton's 2nd law: force required to change something is proportional to its mass, i.e. the heavier it is, the more ass you have to put into it to move, the "more mass, more ass" principle) This is where your slowing down question comes in.

      Now, let's assume that our thought-experiment space is actually filled with something like air or water. If you've ever been in a swimming pool, river, or gale, you know that both air and water can definitely slow you down or move you about. This is called "resistance", and it's basically a form of Newton's 3rd law (every action has an equal and opposite reacion). Now, let's assume two objects of equal mass, but one is a really large sheet while the other is compact like a bullet. Moving through the water/air/solar wind/intergalactic hydrogen medium, this stuff exerts force on our objects as they pass through. However, the sheet interacts with a lot more of the medium, since it has a larger cross-sectional area per unit mass, so it slows down more quickly than our compact bullet. This is why a feather floats to the ground slowly, while a rock simply falls. On a more significant scale, at sufficient speeds, lots of heat gets generated by friction. This is pretty good for us, since the atmosphere protects us from debris from space.

      Hopefully that helps you.

      --
      Disclaimer: The opinions and actions of the US Gov't are in no way representative of those held by this author or its ci
  2. Impossible in this timespan by RabidMoose · · Score: 5, Informative

    (IANARS) There's simply no way that any space agency could prepare and launch a probe with less than three days notice, and likely no good way to pre-build one without knowing what size/speed asteroid we might be lucky enough to launch at.

    1. Re:Impossible in this timespan by PolygamousRanchKid+ · · Score: 4, Funny

      (IANARS) There's simply no way that any space agency could prepare and launch a probe with less than three days notice, and likely no good way to pre-build one without knowing what size/speed asteroid we might be lucky enough to launch at.

      I dunno . . . The Thunderbirds seem to be able to get anywhere they want to go, real fast. And Doctor Who just seems to be able to go where ever he damn well pleases, as well.

      --
      Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
    2. Re:Impossible in this timespan by Hurricane78 · · Score: 4, Funny

      Unfortunately though, they also have the disadvantage of not being real.

      Which is quite unfortunate, in reality.

      --
      Any sufficiently advanced intelligence is indistinguishable from stupidity.
    3. Re:Impossible in this timespan by Nyeerrmm · · Score: 4, Interesting

      While you're absolutely correct, there is a program known as Operationally Responsive Space (ORS) thats being headed up by DoD rather than NASA that is headed in that direction. I think the time-frame they're considering is closer to 2 weeks, but the general idea is to be able to recognize a need, and design, construct and launch a mission in that period of time. That includes getting adjustable plug-and-play parts (GNC, Power, structures, propulsion) that you can tune and modify quickly to fit the mission profile.

      Presumably, a lot of the work to streamline the process of designing the bus and plugging in instruments could be easily translated to space science missions, and if a future opportunity like this were available we could do exactly that. Of course, you'd have to have a pretty interesting guidance system and a very robust structure, since you'd only get an advantage if you stuck the probe in the asteroids path and let it slam into it to get the momentum.

    4. Re:Impossible in this timespan by Puffy+Director+Pants · · Score: 5, Funny

      Dude, if you can make a functional space craft that looks like an English Police box, I'll support your candidacy for head of Nasa.

    5. Re:Impossible in this timespan by idigitallDotCom · · Score: 2, Interesting

      THREE days?????? surely the space agencies had some inkling about this asteroid much longer before now? Surely they do some sort of skywatch/asteroid/meteor monitoring. What's so special about this asteroid that noone knew it was coming around here and how big/fast it is? I'd be seriously worried if 3 days was their minimum time to interception.

      --
      blog.idigitall.com
    6. Re:Impossible in this timespan by Dr.M0rph3us · · Score: 4, Informative

      From TFA:

      "This little cosmic surprise, designated 2009 DD45, turned up two days ago as a 19th-magnitude blip in images taken by Rob McNaught at Siding Spring Observatory in Australia. It was already within 1.5 million miles of Earth and closing fast."

      So no, they had no prior info about this asteroid. And yes, this fact concerns me as well, but this is the problem with asteroids / comets having a low albedo - they're difficult to observe with the usual instruments.

  3. Re:Another perspective by MichaelSmith · · Score: 2, Interesting

    In those few hours it will be greater than 13th magnitude it's velocity will change by about 1km/s or ~30000km/h from the force of the earth alone.

    Most of which it will give back on the way out. So what is the net velocity change for the earth encounter?

    --
    http://michaelsmith.id.au
  4. A potential 3rd moon? by pecosdave · · Score: 2, Interesting

    Assuming of course you count Cruithne as a moon. What happens once it passes our gravity?

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  5. Re:Another perspective by wjh31 · · Score: 2, Insightful

    about Zero when integrated over enough orbits, but for this encounter, while the speed wont change by then end of the encounter, but the velocity will, i think

  6. obligatory by Anonymous Coward · · Score: 2, Funny

    /ducks

  7. Buzz vs. Non-buzz by DynaSoar · · Score: 5, Informative

    Three days notice. 20 to 50 meter diameter. Assume it's dense rock and a vertical impact trajectory into the ocean (avg. 1000 m depth).

    Impact energy 116 kT to 1.8 MT. Very near the lowest energy potential impact of the known NEOs, actually. Not relevant here since the object quite clearly misses. But if and when one doesn't miss, someplace is going to catch a small to medium nuke sized blast, and there won't be time to do squat about it.

    My money says we'll have the capability to defend ourselves against such an impact. The second time.

    --
    "I may be synthetic, but I'm not stupid." -- Bishop 341-B
    1. Re:Buzz vs. Non-buzz by narcberry · · Score: 3, Funny

      There's only so much matter, after enough time, we don't have to worry about anymore collisions.

      I vote we wait it out.

      --
      Modding me -1 troll doesn't make me wrong.
    2. Re:Buzz vs. Non-buzz by Frequency+Domain · · Score: 2, Insightful

      We won't do anything about these things till there's a loss of life. There's a 70% chance it hits the ocean, and with 1MT energy? There's pretty good odds it will go unnoticed by anything but defence satellites.

      You think sea strikes are harmless? The odds of actually hitting a city are pretty small, but the odds of hitting a chunk of water near enough to populated areas to cause tsunami damage are much larger since, according to NOAA, coastal counties in the continental US account for only 17% of land area but have 53% of the population. Imagine what a 10m or more surge from a tsunami could do to the Netherlands, or Miami, or New York. For comparison purposes, the Sumatra tsunami of 2004 was estimated to release around 20MT of energy at the surface, and produced as much as 30m surges hundreds of miles away from the epicenter.

  8. Re:Thirty metres by MichaelSmith · · Score: 2, Informative

    That was me. Must have hit AC by mistake.

    --
    http://michaelsmith.id.au
  9. Re:Another perspective by MartinSchou · · Score: 5, Informative

    1 km/s is EXACTLY 3,600 km/h. Not roughly 30,000 km/h as you suggest.

  10. Parent links to malicious site by Anonymous Coward · · Score: 3, Informative

    Sturly is a redirection service similar to tinyurl. Luckily it provides a preview. The link wants to send you to the same "dragonslair" link that appeared in the 3D game without polygons story from earlier today.

    Looking at the source of the page, it attempts to download a movie on eDonkey, change your AIM name, send off spam emails, open up lots more windows, and probably much more. It also moves the window around so you can't close it, and pops up messages when you try to alt+f4.

    In short; DO NOT CLICK THE LINK.

  11. Armageddon by Samah · · Score: 3, Funny

    Quick, someone notify Bruce Willis!

    --
    Homonyms are fun!
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  12. Re:Small english/metric error, I believe by John+Hasler · · Score: 2, Informative

    > Geosynchronous orbit is 32,000 miles...

    Geosynchronous orbit is 22,236 miles.

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    Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
  13. Re:Another perspective by Overzeetop · · Score: 2, Insightful

    m2/m1xdelta-v, or diminishingly small; that's the useful part about using planetary passes to change velocity - they affect the planet in a negligible way. Kind of like driving to the store makes a negligible change in the CO2 in the atmosphere vs. walking. If all the asteroids started going for a joy ride, or taking vacation past earth every summer just for the fun of it, we'd start to notice. ;-)

    --
    Is it just my observation, or are there way too many stupid people in the world?
  14. Re:Thirty metres by Hooya · · Score: 2, Funny

    > That was me. Must have hit AC by mistake

    No, no.. the meteor didn't hit anything.. but thanks for flying by if it indeed was you.

  15. Close call by mc1138 · · Score: 4, Interesting

    While right now 64,000 puts it fairly far out in terms of all the junk orbiting the earth, it is significantly closer than the moon is. Even if it still missed the earth, just a few thousand kilometers closer and it could reek havoc on all the man-made junk spinning around the Earth. How much potential damage/debris could that cause?

    --
    The musings of just another geek and his junk.
    1. Re:Close call by Nyeerrmm · · Score: 2, Insightful

      Without any actual analysis, I'll go out on a limb and estimate it would cause as much havoc as any large man-made piece of junk out there, like say a dead Soviet satellite. A much larger asteroid would be a different story, since not only would it have a larger footprint, but would also have hard-to-predict gravitational effects on all the satellites that got too near it. Of course, we're doing a pretty good job of detecting larger NEOs now... Apophis is the most problematic, mostly because we simply don't have high enough precision knowledge of its position to know where it will be in 2029 and 2036.

  16. Re:Fourth by Anonymous Coward · · Score: 3, Funny

    ^That this was modded interesting made me lose faith in humanity.

  17. Another one from Klendathu... by allcoolnameswheretak · · Score: 3, Funny

    Their aim is getting better. They will hit us eventually if we don't do something about those Bugs, soon.

  18. So, I used a calc on the impact by Ralph+Spoilsport · · Score: 5, Informative
    the calculator can be found here:
    http://www.lpl.arizona.edu/impacteffects/

    And the results are (assumed that you are 2000km from impact - if it hit it would be in the ocean...)

    Your Inputs: Distance from Impact: 2000.00 km = 1242.00 miles
    Projectile Diameter: 30.00 m = 98.40 ft = 0.02 miles
    Projectile Density: 8000 kg/m3
    Impact Velocity: 17.00 km/s = 10.56 miles/s
    Impact Angle: 90 degrees
    Target Density: 1000 kg/m3
    Target Type: Liquid Water of depth 100.00
    meters, over typical rock.

    Energy: Energy before atmospheric entry: 1.63 x 1016 Joules = 3.90 MegaTons TNT
    The average interval between impacts of this size somewhere on Earth is 314.0 years

    Atmospheric Entry: The projectile begins to breakup at an altitude of 14100 meters = 46100 ft
    The projectile reaches the ground in a broken condition. The mass of projectile strikes the surface at velocity 10.8 km/s = 6.7 miles/s The impact energy is 6.58 x 1015 Joules = 1.57 MegaTons.
    The broken projectile fragments strike the ground in an ellipse of dimension 0.151 km by 0.151 km

    Major Global Changes: The Earth is not strongly disturbed by the impact and loses negligible mass.
    The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
    The impact does not shift the Earth's orbit noticeably.

    Crater Dimensions:
    What does this mean?

    The crater opened in the water has a diameter of 1.4 km = 0.866 miles
    For the crater formed in the seafloor: Crater shape is normal in spite of atmospheric crushing; fragments are not significantly dispersed.
    Transient Crater Diameter: 670 m = 2200 ft
    Transient Crater Depth: 237 m = 777 ft
    Final Crater Diameter: 837 m = 2750 ft
    Final Crater Depth: 179 m = 586 ft

    The crater formed is a simple crater
    The floor of the crater is underlain by a lens of broken rock debris (breccia) with a maximum thickness of 82.8 m = 272 ft.
    At this impact velocity ( Thermal Radiation: What does this mean?

    At this impact velocity ( Seismic Effects: What does this mean?

    The major seismic shaking will arrive at approximately 400 seconds.
    Richter Scale Magnitude: 4.4
    Mercalli Scale Intensity at a distance of 2000 km:
    Nothing would be felt. However, seismic equipment may still detect the shaking.

    --
    Shoes for Industry. Shoes for the Dead.
  19. What if it waits in orbit? by Mathinker · · Score: 2, Interesting

    If you had several such pre-built probes waiting in orbit, you would have a much better chance, no? The probes would have the advantage that they're already out of the deepest part of Earth's gravity well, and that you could choose the one whose orbit is best. I would think that with only two or three you would be able to do what he wanted.

    OTOH, I'm not convinced it would be cost-effective. Depends on how often do asteroids pass by close enough to make it worth our while (and how often they're worth piggy-backing upon), versus the cost saved for getting where you want to go.

  20. Re:Small english/metric error, I believe by Hognoxious · · Score: 2, Funny

    Slashdot is a discussion forum, not a source-citing masturbatory like wikipedia.

    [citation needed]

    --
    Confucius say, "Find worm in apple - bad. Find half a worm - worse."
  21. Re:Fourth by eleuthero · · Score: 2, Funny

    That it took until "fourth" to lose faith in humanity makes you a much more hopeful person than I--all it took for me was yet another "first post" troll