Comments on: Video of asteroid DA14 near Earth last week http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html Brain candy for Happy Mutants Fri, 24 May 2013 15:10:00 +0000 hourly 1 http://wordpress.org/?v=3.4.1 By: David Rasmussen http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1661120 David Rasmussen Thu, 21 Feb 2013 04:43:00 +0000 http://boingboing.net/?p=214285#comment-1661120 Ain't nobody got time for dat. Ain’t nobody got time for dat.

]]> By: Antinous / Moderator http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660905 Antinous / Moderator Thu, 21 Feb 2013 00:02:00 +0000 http://boingboing.net/?p=214285#comment-1660905 Big pixel is good pixel. Big pixel is good pixel.

]]> By: Gabriel Nagmay http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660798 Gabriel Nagmay Wed, 20 Feb 2013 22:24:00 +0000 http://boingboing.net/?p=214285#comment-1660798  Because this http://what-if.xkcd.com/32/  Because this http://what-if.xkcd.com/32/

]]> By: duncancreamer http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660731 duncancreamer Wed, 20 Feb 2013 21:49:00 +0000 http://boingboing.net/?p=214285#comment-1660731 did nobody point an actual telescope at this thing? did nobody point an actual telescope at this thing?

]]> By: flickerKuu http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660725 flickerKuu Wed, 20 Feb 2013 21:47:00 +0000 http://boingboing.net/?p=214285#comment-1660725 Make sure you click on the 720p option so the video is.... the same. Make sure you click on the 720p option so the video is…. the same.

]]> By: Kristopher Larsen http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660717 Kristopher Larsen Wed, 20 Feb 2013 21:41:00 +0000 http://boingboing.net/?p=214285#comment-1660717 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.  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. 

]]> By: Justin Forposting http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660633 Justin Forposting Wed, 20 Feb 2013 20:45:00 +0000 http://boingboing.net/?p=214285#comment-1660633 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. 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.

]]> By: huskerdont http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660559 huskerdont Wed, 20 Feb 2013 19:55:00 +0000 http://boingboing.net/?p=214285#comment-1660559 Where's the Star Trek music? Where’s the Star Trek music?

]]> By: Robbo http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660524 Robbo Wed, 20 Feb 2013 19:37:00 +0000 http://boingboing.net/?p=214285#comment-1660524  And the first thing I wanted to say was that crappy movie trope:  "Enhance!" https://www.youtube.com/watch?v=Vxq9yj2pVWk  And the first thing I wanted to say was that crappy movie trope:  “Enhance!”

https://www.youtube.com/watch?v=Vxq9yj2pVWk

]]> By: Robbo http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660521 Robbo Wed, 20 Feb 2013 19:35:00 +0000 http://boingboing.net/?p=214285#comment-1660521 When the world ends it will look like Minecraft. When the world ends it will look like Minecraft.

]]> By: Finnagain http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660493 Finnagain Wed, 20 Feb 2013 19:16:00 +0000 http://boingboing.net/?p=214285#comment-1660493 That doesn't look dangerous at all! Kind of cute. I hope it will be friends with us. That doesn’t look dangerous at all! Kind of cute. I hope it will be friends with us.

]]> By: chris jimson http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660488 chris jimson Wed, 20 Feb 2013 19:13:00 +0000 http://boingboing.net/?p=214285#comment-1660488  Yeah, and all this time I thought they were vector.  At least. . . that's my memory of playing Asteroids in the arcade.  Yeah, and all this time I thought they were vector. 

At least. . . that’s my memory of playing Asteroids in the arcade.

]]> By: EH http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660483 EH Wed, 20 Feb 2013 19:11:00 +0000 http://boingboing.net/?p=214285#comment-1660483 People call it an asteroid, but that's pure Asteroids Deluxe right there. People call it an asteroid, but that’s pure Asteroids Deluxe right there.

]]> By: dave3000 http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660484 dave3000 Wed, 20 Feb 2013 19:11:00 +0000 http://boingboing.net/?p=214285#comment-1660484 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. 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.

]]> By: chris jimson http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660482 chris jimson Wed, 20 Feb 2013 19:10:00 +0000 http://boingboing.net/?p=214285#comment-1660482 "My God, it's full of stars!" “My God, it’s full of stars!”

]]> By: David Haddad http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660474 David Haddad Wed, 20 Feb 2013 19:07:00 +0000 http://boingboing.net/?p=214285#comment-1660474 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. 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.

]]> By: Hugh D'Andrade http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660446 Hugh D'Andrade Wed, 20 Feb 2013 18:41:00 +0000 http://boingboing.net/?p=214285#comment-1660446 I didn't realize asteroids were so pixelated!  I didn’t realize asteroids were so pixelated! 

]]> By: Boundegar http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660435 Boundegar Wed, 20 Feb 2013 18:35:00 +0000 http://boingboing.net/?p=214285#comment-1660435 You fools!  It's headed right for us! You fools!  It’s headed right for us!

]]> By: plex http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660423 plex Wed, 20 Feb 2013 18:22:00 +0000 http://boingboing.net/?p=214285#comment-1660423 So this is what the end of the world will look like....Thought it would be more high-res. So this is what the end of the world will look like….Thought it would be more high-res.

]]> By: Sean Nelson http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660420 Sean Nelson Wed, 20 Feb 2013 18:21:00 +0000 http://boingboing.net/?p=214285#comment-1660420 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? 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?

]]> By: duaneromanell http://boingboing.net/2013/02/20/video-of-asteroid-da14-near-ea.html#comment-1660412 duaneromanell Wed, 20 Feb 2013 18:18:00 +0000 http://boingboing.net/?p=214285#comment-1660412 At :13 sh*t just got real! At :13 sh*t just got real!

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