INCOMING!, Detection and observation of Earth-approaching asteroids. |
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INCOMING!, Detection and observation of Earth-approaching asteroids. |
 Feb 15 2013, 01:15 AM
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#286
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Senior Member  Group: Members Posts: 4586 Joined: 5-April 05 From: Canada Member No.: 227  |
Fun! But the Canadian crater is Charlevoix. Still, it's not an L of a difference, is it?
Phil PS - darn, I've slipped onto the next page. That weakens my impact factor. -------------------- ... because the Solar System ain't gonna map itself.
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Feb 18 2013, 05:56 AM
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#287
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 Senior Member Group: Admin Posts: 2442 Joined: 21-December 05 From: Canberra, Australia Member No.: 615 |
ADMIN: Posts on the Chelyabinsk meteor event have been split into their own thread here.
Please continue the discussion there. For all other "the sky is falling" events, please continue as per normal 
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Feb 19 2013, 07:05 AM
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#288
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 Senior Member Group: Members Posts: 1154 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
radar images of 2012DA14
http://www.oosa.unvienna.org/pdf/pres/stsc...2013neo-05E.pdf -------------------- I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.
James Van Allen |
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Feb 19 2013, 08:42 PM
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#289
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Senior Member Group: Members Posts: 1154 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
and a video: Early Radar Observations of Asteroid 2012 DA14
-------------------- I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.
James Van Allen |
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Feb 19 2013, 08:56 PM
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#290
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 Senior Member Group: Members Posts: 3119 Joined: 9-February 04 From: Minneapolis, MN, USA Member No.: 15 |
At least over the period observed, I only see rotation along a single axis. That would be somewhat rare, wouldn't it?
-the other Doug -------------------- “The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
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Feb 19 2013, 09:16 PM
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#291
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Senior Member Group: Members Posts: 4586 Joined: 5-April 05 From: Canada Member No.: 227 |
No, it's what we would expect from a fairly rapid rotator like this. But radar images are notoriously difficult to interpret so I would want to see more results of shape and rotation modelling before drawing any conclusions.
Phil -------------------- ... because the Solar System ain't gonna map itself.
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Feb 24 2013, 04:32 PM
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#292
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Senior Member Group: Members Posts: 1154 Joined: 3-August 06 From: 43° 35' 53" N 1° 26' 35" E Member No.: 1004 |
the Canadian NEOSSat, the first satellite dedicated to the detection of near Earth asteroids is due for launch tomorrow in India
http://www.asc-csa.gc.ca/eng/satellites/neossat/ -------------------- I'm one of the most durable and fervent advocates of space exploration, but my take is that we could do it robotically at far less cost and far greater quantity and quality of results.
James Van Allen |
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Feb 25 2013, 02:25 PM
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#293
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 Member Group: Members Posts: 967 Joined: 26-July 08 Member No.: 4270 |
Launch was successful.
-------------------- -- Hungry4info (Sirius_Alpha)
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Feb 26 2013, 12:51 AM
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#294
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Member Group: Members Posts: 567 Joined: 4-September 06 From: Boston Member No.: 1102 |
-------------------- Floyd
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May 30 2013, 10:41 PM
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#295
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Senior Member Group: Members Posts: 1106 Joined: 14-October 05 From: Seattle Member No.: 530 |
Goldstone finds a satellite for 1998 QE2, "Ocean Liner" size comparison results:
http://cosmiclog.nbcnews.com/_news/2013/05...oon-radar-shows |
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May 31 2013, 10:53 AM
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#296
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 Member Group: Members Posts: 122 Joined: 12-February 12 Member No.: 6336 |
QUOTE (stevesliva @ May 31 2013, 12:41 AM)  Goldstone finds a satellite for 1998 QE2, "Ocean Liner" size comparison results: With the satellite about 1/4 the size of the main body, it might qualify 1998 QE2 as a binary asteroid. |
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May 31 2013, 11:04 AM
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#297
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 Senior Member Group: Moderator Posts: 6501 Joined: 8-December 05 From: Los Angeles Member No.: 602 |
Hopefully not too OT, but I'm wondering just exactly how asteroids even have moons.
The only mechanism I can think of to create them is a very low relative speed impact, which would seem to be a rare event. However, asteroid moons seem to be fairly common, esp. for low-mass objects. (Note that Vesta apparently has none; jury's still out for Ceres. Gravitational capture would be a more likely mechanism for moons around a high-mass body, but thus far we haven't seen much of that.) Might be something else happening here. Calving, perhaps, off of the main body over time due to heating/cooling cycles? -------------------- A few will take this knowledge and use this power of a dream realized as a force for change, an impetus for further discovery to make less ancient dreams real.
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May 31 2013, 02:21 PM
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#298
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 Bloggette par Excellence Group: Admin Posts: 3982 Joined: 4-August 05 From: Pasadena, CA, USA, Earth Member No.: 454 |
From "FORMING THE OBSERVED BINARY ASTEROID POPULATION. S. A. Jacobson1 and D. J. Scheeres2, 1Dept. Astrophysical and Planetary Sciences, Univ. of Colorado, Boulder, USA (seth.jacobson@colorado.edu), 2Dept. Aerospace Engineering Sciences, Univ. of Colorado, Boulder."
QUOTE Rotational fission results in the formation of all classes of observed near-Earth asteroid (NEA) binaries. The NEA population is constantly evolving due to the incredible influence of electromagnetic radiation. The YORP effect, torque from the incident solar irradiation and thermal radiation of an asymmetric body, can rotationally accelerate individual asteroids until centrifugal accelerations match gravitational accelerations, releasing part of the body into orbit and creating a binary asteroid system–i.e. rotational fission. This process has been theoretically predicted and modeled in detail [1, 2], as well as observationally confirmed [3]. The figure below shows the evolutionary pathways from rotational fission to each of the observed binary classes indicated by an underline. q is the mass ratio of the binary (secondary / primary mass). Primary defined to be more massive. Read more here. Or google for binary asteroid formation. -------------------- |
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May 31 2013, 03:27 PM
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#299
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Senior Member Group: Members Posts: 4586 Joined: 5-April 05 From: Canada Member No.: 227 |
Another explanation - forget where it came from - a large asteroid is blown apart in a big impact. Two chunks are ejected on almost parallel trajectories, and as they move outwards they stay together and become a binary. I think this dated from about the time Dactyl was discovered orbiting Ida.
Phil -------------------- ... because the Solar System ain't gonna map itself.
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Lo-Fi Version | Time is now: 19th June 2013 - 06:17 PM |
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