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21 Responses to “Video of asteroid DA14 near Earth last week”

  1. At :13 sh*t just got real!

  2. Sean Nelson says:

    Does anyone know why it is the case that we have detailed images of distant planets and galaxies, but have no images of decent resolution of this object that passed through the moon’s orbit?

    • David Haddad says:

      2012 DA14 was moving significantly faster, relative to us, than more distant objects.
      It’s also much smaller than a planet. This isn’t a problem of angular size, but of the amount of light being sent back to us. A larger object reflects more light for us to see, and DA14 wasn’t sending back much at all. That’s part of the reason that the video shows a RADAR-like scan instead of visible light.

    • dave3000 says:

      Because it’s both extremely dim and moving extremely fast. Those glorious images of distant objects require very long exposures and telescopes can only move fast enough to compensate for the earth’s orbit (or for being in orbit like the Hubble). There is no way they would be able to track an object moving that fast. The radar images were produced by using large antennae and blasting a huge amount of radio waves at it to “brighten” it up.

    • Kristopher Larsen says:

      In part because radar imaging works fundamentally different that other types of light-based imaging. Unlike cameras that use a 2-d sensor and lenses to create the image, with long exposure times as some others have mentioned, radar works in the range/doppler domain. The radar signal transmitted from earth is reflected by the asteroid and received by large radio telescopes. The reflected light from various parts of the asteroid are delayed in time, based on the slight differences in distance between the telescope and asteroid, and doppler shifted in frequency, based on whether the reflecting region of the asteroid is moving towards or away from the telescope. 

      Deconvolution of the range/doppler data converts it to a 2-d spatial image for viewing. The advantage to this system is that the spatial resolution of the radar imaging system is independent of the distance to the asteroid. Whether it’s as close as this one, or out near the orbit of Jupiter, we can image it at 4m/pixel. Of course, this isn’t strictly true because the amount of reflected signal from the asteroid falls off as the fourth power of the distance to the object, so it doesn’t have to be too far away for the signal levels to be too low to observe. But that’s why the displayed ‘size’ of this asteroid doesn’t change despite a change in distance of nearly a factor of 3. The number of reflected photons would have changed by a large amount, but the spatial resolution was fixed by the observation parameters set at the telescope. 

  3. plex says:

    So this is what the end of the world will look like….Thought it would be more high-res.

  4. Boundegar says:

    You fools!  It’s headed right for us!

  5. I didn’t realize asteroids were so pixelated! 

  6. chris jimson says:

    “My God, it’s full of stars!”

  7. Finnagain says:

    That doesn’t look dangerous at all! Kind of cute. I hope it will be friends with us.

  8. Robbo says:

    When the world ends it will look like Minecraft.

  9. huskerdont says:

    Where’s the Star Trek music?

  10. holy crap!  I’m glad I live on the ground floor of my building and drive a low profile car.  Can’t be too careful these days.

  11. flickerKuu says:

    Make sure you click on the 720p option so the video is…. the same.

  12. duncancreamer says:

    did nobody point an actual telescope at this thing?