Forgot your password?
typodupeerror
Space Science

Small Asteroid To Buzz Earth 171

Posted by kdawson
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.
This discussion has been archived. No new comments can be posted.

Small Asteroid To Buzz Earth

Comments Filter:
  • Piggy ride! (Score:5, Interesting)

    by Chicken_Kickers (1062164) on Sunday March 01, 2009 @06:01PM (#27033273)
    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.
    • by RabidMoose (746680) on Sunday March 01, 2009 @06:04PM (#27033303) Homepage
      (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.
      • by PolygamousRanchKid (1290638) on Sunday March 01, 2009 @06:24PM (#27033507)

        (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.

        • by Hurricane78 (562437) <.gro.todhsals. .ta. .deteled.> on Sunday March 01, 2009 @07:06PM (#27033909)

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

          Which is quite unfortunate, in reality.

        • by dpilot (134227)

          But Dr. Who only gets exactly where he pleases when it satisfies the writers. Most of the time it seems that some sort of space-time vortex sucks him off-course, or the Tardis misbehaves, or other such circumstance landing him in the wrong space/time.

          • But Dr. Who only gets exactly where he pleases when it satisfies the writers. Most of the time it seems that some sort of space-time vortex sucks him off-course, or the Tardis misbehaves, or other such circumstance landing him in the wrong space/time.

            Just once they should go somewhere and nothing happens - maybe only a 5min episode to keep us hooked.

            Speaking of near misses.
            Don't forget that many many years ago the Doctor (and Adric) accidently set off life on this planet. Though only one of them lived to tell about it I guess.

        • And Doctor Who just seems to be able to go where ever he damn well pleases, as well.

          Well sure, once you can go anywhen, it makes it a lot easier to go anywhere. Anyplace was everyplace (and very small to boot) at some point in time, so you go backwards in time until it's all close together, relocate, and then go forward in time staying with your new location...

        • by Puffy Director Pants (1242492) on Sunday March 01, 2009 @09:53PM (#27035235)

          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.

          • by Kjella (173770)

            Without the time machine? Meh. Besides, why do you want to copy the only non-functional technology on the TARDIS? Chameleon circuit, now we're talking...

      • by Nyeerrmm (940927) on Sunday March 01, 2009 @07:55PM (#27034297)

        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.

      • 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-b

      • Re: (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.
        • by Dr.M0rph3us (1256296) on Monday March 02, 2009 @11:06AM (#27040057)

          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.

    • Re:Piggy ride! (Score:4, Insightful)

      by Anonymous Coward on Sunday March 01, 2009 @06:05PM (#27033309)
      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).
    • Re:Piggy ride! (Score:4, Insightful)

      by evanbd (210358) on Sunday March 01, 2009 @06:06PM (#27033323)
      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.
      • With a thirty metre object you could almost snare it with a net. Then you would need a shock absorbing tether to match velocities. 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
        • Re: (Score:3, 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

          • 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.

            So use a long tether.

          • by drinkypoo (153816)

            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.

            Some spiders catch prey many times their size by creating webs which include stress-release points which consist of a glob of sticky material filled with some gathered web. When a heavy impact hits the web, the gathered material pays out and distributes an immense amount of force.

            By making the tether stretch to 100x its length you could reduce the shock to 90 Gs nominal, which is theoretically doable. heh heh.

            I don't think we'll do it today or tomorrow, but maybe next week, eh?

      • Suppose the main (heavy) probe was sitting in GEO or something, but shot a lightweight harpoon into the meteor's orbit. Then the trick would be to get the tether to pay out quickly, and the main probe to slowly increase tension so it can accelerate into the meteor's orbit.

    • Re:Piggy ride! (Score:5, Insightful)

      by amorsen (7485) <benny+slashdot@amorsen.dk> on Sunday March 01, 2009 @06:06PM (#27033325)

      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...

    • Re:Piggy ride! (Score:5, Informative)

      by CrimsonAvenger (580665) on Sunday March 01, 2009 @06:13PM (#27033381)

      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.

      • 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?

        Well, you could fire a bullet straight up. If it peaked at say a mile up, its velocity would be zero, but, it could still hit a plane regardless of its velocity if you timed it right.

        In the case of the asteroid, we could theoretically, anyway, shoot up something to an altitude of 64k km, have it "hit" the asteroid, and then continue on its merry way. Tha

    • Re:Piggy ride! (Score:5, Informative)

      by meringuoid (568297) on Sunday March 01, 2009 @06:45PM (#27033719)
      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.

      • by Ihmhi (1206036)

        Has nobody on Slashdot ever heard of harpoons or grappling hooks?

        IANAA (I Am Not An Astrophysicist), but let's say hypothetically that this asteroid is 1 km in diameter. We send up a probe with a 1.1km tether. The probe releases the tether into the path of the asteroid, and the end of the tether has hooks. When the asteroid smacks into the tether, the probe hooks into it.

        At this crucial moment, the probe must begin accelerating to match as much of the speed of the asteroid as possible without overtaking it.

        • by honkycat (249849)

          IAAA, granted not one who studies near-Earth objects or asteroids...

          But, beyond direct exploration of the asteroid itself (and, ok, the kickass-cool factor of riding an asteroid), there really is little purpose to tagging along. Furthermore, it's serious sci-fi to even contemplate doing so. Your tether idea is interesting, but remember the speed difference between the asteroid and your probe is gonna be thousands of MPH so we're not just talking about a climbing rope here... so the path from "interesting"

          • I can think of a few purposes.

            (1) Set automated computer/video aboard the asteroid, and search out other asteroids. Plot trajectories, and relay info back to earth.

            (2) Use asteroid mounted telescopes to take photos of (and out of) the solar system at different times and angles. These are occasional, but are all preset according to time, date, and direction, and match from one asteroid to another. Transmit data to other asteroid riding probes, and any time a probe comes close to earth, tra

        • by mea37 (1201159)

          I've never heard of a harpoon or grappling hook that could survive the use you want to put it to. The hook, and/or the tether, and/or the probe, and/or the asteroid itself would be destroyed during the tug-of-war between the asteroid and the probe.

          There's also a very real concern that the attempt to accelerate the probe would drag the asteroid into a much less interesting orbit. Equal and opposite reactions, conservation of momentum, etc. My guess is, if you could make the probe survive the attempt to te

          • by Ihmhi (1206036)

            The asteroid wouldn't change direction under its own power. Such an assumption would be absolutely ludicrous on my part. I was talking more about gravitational forces of things bigger than the asteroid affecting its trajectory.

            • by mea37 (1201159)

              The point is, any external influence on the asteroid's path (such as a large gravitational pull) would have exactly the same impact on the probe's path, whether the asteroid is present or not. Gravity affects all matter equally.

    • Re:Piggy ride! (Score:4, Interesting)

      by pcolaman (1208838) on Sunday March 01, 2009 @07:52PM (#27034269)
      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.
    • Re: (Score:3, Insightful)

      by MrMista_B (891430)

      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.

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

        Good imagery. Note that the the rock is moving about five times as fast (relative to Earth) as the fastest bullet.

    • I think the notion of relative velocities is enough to eliminate that prospect entirely. If you don't match velocities with the object your piggybacking onto, you're crashing into it. If you do match speeds, then what was the point of the piggybacking in the first place?

    • by matt4077 (581118)
      That wouldn't make much sense. To land on the asteroid, you need to be about as fast as it is, or your lander will just be hit by a very fast moving rock. When you have invested all the energy to get up to that speed, you could equally well just turn of the engines and be subject to gravity, just like the asteroid, which will give you that tour around the solar system without any further energy.
      • What if you placed a probe directly in the path of the asteroid, then unfurled a few hundred km long spring. Then the asteroid would compress the spring as it began to impact the probe. One the spring was fully compacted it would redirect the energy into the probe providing a free speed boost.

    • With any luck the probe would modify the asteroid's orbit just enough so that the next time round it slammed into earth.

  • by pecosdave (536896) on Sunday March 01, 2009 @06:18PM (#27033427) Homepage Journal

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

    • 5th, actually [wikipedia.org]

      Known satelittes and quasi-satellites wrt Earth

      Moon
      Cruithne (Earth's first known quasi-satellites)
      2003 YN107
      (164207) 2004 GU9

  • obligatory (Score:2, Funny)

    by Anonymous Coward

    /ducks

  • Buzz vs. Non-buzz (Score:5, Informative)

    by DynaSoar (714234) on Sunday March 01, 2009 @06:36PM (#27033619) Journal

    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 have this idea in my head about a space transportation system based around tethers, solar sails and aerobraking. There are a lot of tricks you could do once attached to an object like this. You could convert angular momentum from the object into linear momentum by letting the asteroid swing you around then releasing at the appropriate moment. You could do a slingshot by pushing off the asteroid then retracting the tether at the appropriate moment.

      It could be a very hairy but profitable way to travel.
    • My money says we'll have the capability to defend ourselves against such an impact. The second time.

      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.

      I'd guess we'll get near miss after near miss, we'll ignore Tunguska-scale impacts at sea and in the tundra and in the desert just like we ignored Shoemaker-Levy 9... Nobody will fund a serious def

      • just like we ignored Shoemaker-Levy 9...

        In what way did we ignore Shoemaker-Levy 9? That wasn't our planet after all.

      • Re: (Score:3, 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 [noaa.gov], 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 relea

        • 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.

          Okay. So that's 20 times the 1MT we're talking about. So that would be 1.5m surge.

          I think New York is safe.

          • I doubt the wave's amplitude scales linearly against energy, or cannonballs into a pool would produce negligible results.

            Somebody below gave a link to a site which calculates that the crater opened in the water could have a diameter of 1.4km. I'm inclined to believe you'd see more than a 1.5m surge if something punched a 1.4km hole in the ocean along the continental shelf.

        • by drinkypoo (153816)

          Imagine what a 10m or more surge from a tsunami could do to the Netherlands, or Miami, or New York.

          I do every day, but it still never happens. :(

    • by narcberry (1328009) on Sunday March 01, 2009 @08:15PM (#27034473) Journal

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

      I vote we wait it out.

    • by MtViewGuy (197597)

      If what I've read about large meteor impacts is correct, a 30 meter sized meteor impacting the ground not only will have an explosive yield around that of the W88 warhead used on the Trident II missile (circa 475 kT), but also you have the highly dangerous issue of local fallout where the fallout is burning ash around 1,200 degrees F.! That right there will start massive firestorms many miles away from the point of impact.

  • This is ghostwriter asking for Permission to Buzz the Earth.

  • Armageddon (Score:4, Funny)

    by Samah (729132) on Sunday March 01, 2009 @07:05PM (#27033907)
    Quick, someone notify Bruce Willis!
  • Close call (Score:5, Interesting)

    by mc1138 (718275) on Sunday March 01, 2009 @08:05PM (#27034377) Homepage
    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?
    • Re: (Score:3, Insightful)

      by Nyeerrmm (940927)

      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

      • by swillden (191260)

        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.

        Well, that and its habit of enslaving humans to feed its goa'uld power trip fantasies.

    • Let me ask the resident experts: With all the different telescopes that litter the earth, how is it that we miss these types of objects coming so close to our planet? I know that space is vast (practically beyond rational imagination), but is there a way to observe a region of space encompassing several days/weeks/months with objects traveling at a certain speed? What would those costs be? (I bet it would be under 700 Billion USD)

      I found this article pretty interesting about a space based constellaton of sa

      • It is going to require an 8" telescope to see it at 64,000 km. Brightness is inversely proportional to the square of distance. Extrapolate.

  • by allcoolnameswheretak (1102727) on Sunday March 01, 2009 @08:16PM (#27034477)
    Their aim is getting better. They will hit us eventually if we don't do something about those Bugs, soon.
  • by Ralph Spoilsport (673134) on Sunday March 01, 2009 @08:29PM (#27034573) Journal
    the calculator can be found here:
    http://www.lpl.arizona.edu/impacteffects/ [arizona.edu]

    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.

    • by dargaud (518470)

      Transient Crater Depth: 237 m [...] Richter Scale Magnitude: 4.4

      Huh ? You make a 200m deep hole in the ground in one second and it doesn't even register as a worthwhile earthquake ?!? There must be something wrong here.

  • If it's going to be closest to Tahiti, why isn't that the best place to observe it from? Papeete, perhaps?

Real computer scientists don't comment their code. The identifiers are so long they can't afford the disk space.

Working...