The 60-inch telescope on Mount Lemmon is one of three telescopes used in the Catalina Sky Survey.

Near Earth Asteroid 2010 GU21 Swoops By Earth On May 5

Article written: 3 May , 2010
Updated: 24 Dec , 2015


The Near-Earth Asteroid (NEA) 2010 GU21 was discovered by the Catalina Sky Survey on April 5 2010 (MPEC 2010-G55) and has been designated as a Potentially Hazardous Asteroid (PHA) by the Minor Planet Center. The asteroid will pass within approximately 8 lunar distances on May 05.25 2010 UT… But why wait when we have Joe Brimacombe on our side?

2010 GU21 is photometrically surmised to be a X-type asteroid and very low-albedo… so dim, in fact, that it only manages about a magnitude 18. However, if you give Joe a magnitude 18 blip, he’ll send you back an image! Just watch how fast this crazy little thing travels….

And for heaven’s sake, don’t take the impact seriously! While eight moon distances (roughly two million miles) is darn close in astronomical terms, we’re quite safe when it comes to physical distance. But, with only a couple of million miles separating us, this would be a great time for radar targeting and studying (NEA) 2010 GU21’s rotation period. What’s more, it’s also on the list for the Delta-v for spacecraft rendezvous with all known near-Earth asteroids.

In the meantime, with only two days until 2010 GU21’s closest approach, you’d best keep up your car payments and still plan on keeping those weekend promises. It’s fun to surmise what might what might happen if it were a wee bit closer…

Or is it?

Many thanks to Joe Brimacombe for sharing his awesome video with us!

10 Responses

  1. Member
    geraldspace says


  2. Member

    @ geraldspace,

    That’s exactly what the dinosaurs did 65 million years ago, and look what happened to them!

  3. Marc Tiedemann says

    but did the dinosaurs have telescopes and computers to calulate the trajectory of the asteroid? NO! they didn’t even know what an asteroid is^^

  4. TerryG says

    The demise of the dinosaurs was due to their discovering tobacco products 🙂 but getting back to more recent events…

    NEA discoveries, including PHAs, currently occur at the rate of over 400 per year, three quarters of which are found by the Catalina Survey. It’s reassuring to know someone is looking out for us.

    Is there any word on the target candidate list for the human space flight mission to an asteroid? If this mission takes place before the human space flight to Mars, then one could assume by the degree of difficulty, that the target candidate asteroids are NEA’s rather than asteroid belt objects. If so, does it follow that the candidates are on the “Delta-v for spacecraft rendezvous” list of 6904 objects mentioned above? see

    2010 GU21 should be fairly dim at closest approach so good luck to all amateur astronomers attempting to observe it.

  5. Member
    Aqua says

    Yikes! Now WHERE did I put my hard hat and gold undies? Which comes first anyway? the asteroid or some dumb human trick?

  6. TerryG says

    Ah…so that was you at the Village People star party? 🙂

  7. diatoms says

    Great music!!!

  8. Member
    Aqua says

    No TerryG… that was me digging a shelter~

    Remember – not ‘If’, but ‘When’…..*

  9. pegleg says

    when telling us theirs something in the sky why not show us where abouts it is in relation to constellations etc ? tell us if its visible to naked eye etc ! help your readers out. ps use to know when u can see the iss international space station, follow me on twitter for astronomy stuff i am @chained

  10. Mister T says

    DANG it missed!!

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