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Qwickdraw
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Meet DA14's little brother?
      #5680715 - 02/15/13 06:12 AM

Is this a companion of DA14? Here is some incredible footage of a huge Russian meteorite explosion.

Web Link


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Jarad
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Re: Meet DA14's little brother? new [Re: Qwickdraw]
      #5680799 - 02/15/13 08:00 AM

That's pretty cool - much better than the video on CNN that just shows the smoke trail afterward.

Jarad


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Qwickdraw
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Re: Meet DA14's little brother? new [Re: Jarad]
      #5680806 - 02/15/13 08:08 AM

Quote:

That's pretty cool - much better than the video on CNN that just shows the smoke trail afterward.

Jarad




I would be curious of the trajectory to see if it is at all parallel with DA14's.


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Ebyl
super member


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Re: Meet DA14's little brother? new [Re: Qwickdraw]
      #5680816 - 02/15/13 08:15 AM

Some experts have been weighing in to say it does not have the proper trajectory to be connected with 2012 DA14. Others have said it's too early to know that for sure.

Most conjecture I've read regarding the meteor's trajectory puts it at somewhere between east to west and east to south. Assuming that's reasonably accurate, I don't see how it could be connected with 2012 DA14.


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deSitter
Still in Old School


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Re: Meet DA14's little brother? new [Re: Ebyl]
      #5680824 - 02/15/13 08:24 AM

I don't think there is a single person on the various cable news anchor staffs with even an elementary school understanding of science in general or astronomy in particular. At least the NY Times got the word - bolide - right. CNN stated METEOR SHOWER OVER RUSSIA. Pitiful!

-drl


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Ravenous
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Re: Meet DA14's little brother? new [Re: Ebyl]
      #5680847 - 02/15/13 08:35 AM

Quote:

Some experts have been weighing in to say it does not have the proper trajectory to be connected with 2012 DA14. Others have said it's too early to know that for sure.



They're probably not in the same orbit, if you think about it.

2012 DA14 will pass from the southern to northern hemisphere. This impact was in Russia, near Kazakhstan. If it was on the same orbit I doubt it would have been able to hit that for North - it would have struck somewhere much farther south, and most likely in the southern hemisphere itself.


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Ebyl
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Reged: 07/04/12

Re: Meet DA14's little brother? new [Re: Ravenous]
      #5680862 - 02/15/13 08:43 AM

"Astronomers at the Pulkovo Observatory outside St Petersburg say they believe the meteorite that crashed into the South Urals this morning was linked to the approach of the 2012DA14 asteroid, which is to make a close shave with the Earth at a distance of just 27,000 kilometers tonight."

That is the only report I've seen with anyone qualified going so far as to say they're linked. Doesn't mean there aren't others, but there is at least one, I guess. We'll see how it gets sorted out as more time passes.


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Jason H.
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Re: Meet DA14's little brother? new [Re: Ebyl]
      #5680976 - 02/15/13 09:32 AM

"Meteor injures more than 900 in Russian city"

Washington Post Story

Meteorite Fragments Are Said to Rain Down on Siberia
New York Times Story

2013 Russian meteor event (wikipedia article gives very specific details on location and other relevant info.)
Wikipedia Article


Jason W. Higley

Edited by Jason H. (02/15/13 09:47 AM)


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deSitter
Still in Old School


Reged: 12/09/04

Re: Meet DA14's little brother? new [Re: Ebyl]
      #5680988 - 02/15/13 09:36 AM

BOOM!

http://www.youtube.com/watch?v=1kvHl5Qcnzc

-drl


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Jarad
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Re: Meet DA14's little brother? new [Re: Ravenous]
      #5681170 - 02/15/13 11:03 AM

Ravenous nailed it. NASA has an update here. It says:

"According to NASA scientists, the trajectory of the Russian meteorite was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russian meteorite and analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14's trajectory is in the opposite direction, from south to north."

Jarad


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Qwickdraw
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Re: Meet DA14's little brother? new [Re: Jarad]
      #5681215 - 02/15/13 11:27 AM

Quote:

Ravenous nailed it. NASA has an update here. It says:

"According to NASA scientists, the trajectory of the Russian meteorite was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russian meteorite and analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14's trajectory is in the opposite direction, from south to north."

Jarad




Ravenous may have gotten it right but for the wrong reasons.
No fault of Ravenous as we were all just speculating at the time and we didn't have as much data as we do now.


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Qwickdraw
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Re: Meet DA14's little brother? new [Re: Qwickdraw]
      #5681233 - 02/15/13 11:35 AM

In modern history there has only been one recorded event of a person getting struck by a meteorite. I wonder with the roughly 1,000 reported injuries if that is about to change.

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deSitter
Still in Old School


Reged: 12/09/04

Re: Meet DA14's little brother? new [Re: Qwickdraw]
      #5681243 - 02/15/13 11:39 AM

I'm sure almost all of that is flying glass injury.

-drl


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photonovore
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Re: Meet DA14's little brother? new [Re: Jarad]
      #5681271 - 02/15/13 11:53 AM

I ran this through Melosh's impact effects calculator and the smallest object traveling at 30km/sec (*very* fast, estimated by Russian Space agency according to wiki) entering at 45degrees composed of dense rock (3000kg/cubic meter) is 33 meter diameter weighing in at 51,000 metric tons--which produces a overpressure wave of about 1psi arriving about 40 seconds after the corresponding visual event. Changing the density to that of an iron object (8000kg/cu.meter) moves the diameter down to about 16 meters/17000 metric tons with the same expected overpressure of about 1psi (minimum to correspond with depicted damage). Energy of airburst between 1.5 (iron) and 4.5 (dense rock) megatons. Airburst occurs at 46,000ft for rock, 31000ft for iron.

Yet--the Russian Academy of Science declares it as a "ten ton" object (from wiki). There is no way i found to manipulate a ten ton anything into something that could cause the damage etc reported.

???

The Impact calculator is based on what I understand to be *the* paper on impact effect estimation... as a person interested in crater formation generally, i wonder why the massive contradiction between what is coming out of the media vis a vis mass/size vs. the observed effects on the ground...?


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Jarad
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Re: Meet DA14's little brother? new [Re: Qwickdraw]
      #5681276 - 02/15/13 11:56 AM

Quote:

Ravenous may have gotten it right but for the wrong reasons.




No, he nailed it right on. He noted that DA14's orbit is south to north, and correctly pointed out that in order to hit so far north in the northern hemisphere this bolide couldn't have been travelling in that direction. He didn't have the additional info that the smoke trail indicated the bolide was actually travelling north to south, but he figured out from the geometry of the earth that it could not be south to north.

Good attention to detail on his part.

Jarad


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deSitter
Still in Old School


Reged: 12/09/04

Re: Meet DA14's little brother? new [Re: photonovore]
      #5681279 - 02/15/13 11:58 AM

Jeff Masters

http://classic.wunderground.com/blog/JeffMasters/article.html

-drl


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deSitter
Still in Old School


Reged: 12/09/04

Re: Meet DA14's little brother? new [Re: deSitter]
      #5681301 - 02/15/13 12:09 PM

I think this was a scout ship and that DA14 will make a non-ballistic turn at 2:30. Klaatu barada nikto.

-drl


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PhilCo126
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Re: Meet DA14's little brother? new [Re: deSitter]
      #5681355 - 02/15/13 12:31 PM

A few "simple" rules:

These dark objects smaller than 50 meter are very hard to detect (even on detailed astro-photos)
Size of the object (leftover after re-entry) X 20 = roughly diameter impact crater
Spaceflight debris mostly burns up in West to East direction (the direction it's mostly launched - other than polar orbits)
Impacts happen all the time, check 2013 so far:
http://thelatestworldwidemeteorreports.blogspot.be/



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Jason H.
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Re: Meet DA14's little brother? new [Re: Qwickdraw]
      #5681525 - 02/15/13 01:36 PM

Regarding the title of this post, the timing is interesting. Here's an animation of DA 14

http://en.wikipedia.org/wiki/File:2012_DA14.ogg

and info on the orbital period (i.e. slower)
http://en.wikipedia.org/wiki/2012_DA14

I was going to make an analogy of a skater being overtaken by a car, but I don't want to get beaten up. It's interesting timing anyway. I guess in a half hour or later today we'll know if it's a swarm/cluster?

I'm watching for flashes remembering 'Duck and cover' from the atomic age.

Jason H.


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Kaelin
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Re: Meet DA14's little brother? new [Re: Qwickdraw]
      #5681691 - 02/15/13 02:43 PM

Collection of various videos of the meteorite fall in Russia:

http://www.guardian.co.uk/science/2013/feb/15/meteorite-explosion-shakes-russian

First photo of crater in the Russian boondocks:

http://news.nationalgeographic.com/news/2013/02/pictures/130215-russia-meteor...


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Glassthrower
Vendor - Galactic Stone & Ironworks
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Re: Meet DA14's little brother? new [Re: Kaelin]
      #5682091 - 02/15/13 06:11 PM

I recently spoke to a friend of mine who works at the University of Hawaii's institute of astronomy. One of the highly-placed directors there (who is new) is hostile towards meteoritics and openly insults meteoritics as not being relevant to science of astronomy. This Russian event makes that director sound like a fool.

I can't wait to see what is recovered. An event like this must have dropped meteorites. Here in the USA, we have entities like Galactic Analytics that could have confirmed the drop and plotted the strewnfield.

Beware any meteorites offered for sale from this fall - especially this early in the recovery. They will be fakes. It will take some time for genuine specimens to hit the market, if they do at all.

Best regards,

MikeG

PS - we better keep funding our "eyes on the skies" programs!


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Jason H.
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Reged: 11/23/07

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Re: Meet DA14's little brother? new [Re: Qwickdraw]
      #5682420 - 02/15/13 09:48 PM

This video catches the cloud, then multiple sonic booms and echoes, smashing glass, car alarms going off, and gives a good sense of the scale and sense of urgency after the guys run down the block and image part of the other end of the trail and people coming out of buildings.

Here's the link.

Edit adding addtional short but wow sonic booms video link

I bet they fund asteroid searches now

Jason H.

Edited by Jason H. (02/15/13 11:13 PM)


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shawnhar
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Re: Meet DA14's little brother? new [Re: Jason H.]
      #5682671 - 02/16/13 12:37 AM

Tunguska doesn't seem so mysterious anymore.
If this had happened over Moscow in the 70's we would have been nuked for sure.


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deSitter
Still in Old School


Reged: 12/09/04

Re: Meet DA14's little brother? new [Re: shawnhar]
      #5682782 - 02/16/13 03:11 AM

Good point, this sets to the books the active cause of that earlier event, and could possibly calibrate it - and in the very same part of the world, on the very day of a near miss - ... gives pause.

-drl


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Qwickdraw
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Re: Meet DA14's little brother? new [Re: Jarad]
      #5682924 - 02/16/13 08:05 AM

Quote:

Quote:

Ravenous may have gotten it right but for the wrong reasons.




No, he nailed it right on. He noted that DA14's orbit is south to north, and correctly pointed out that in order to hit so far north in the northern hemisphere this bolide couldn't have been travelling in that direction. He didn't have the additional info that the smoke trail indicated the bolide was actually travelling north to south, but he figured out from the geometry of the earth that it could not be south to north.

Good attention to detail on his part.

Jarad




Jarad,

Not to beat a dead horse but I respectfully disagree.
In his post Ravenous made no reference to Earth geometry references as a reason for them not being companions. His point was if it had been the same orbit as DA14 it would be very doubtful that it could have landed in the northern hemisphere. Key word here which I agree with is "doubtful ". I am not sure of all of the orbital elements nor do they matter for the purpose of this discussion as it was all speculation at the time but if the meteor would have been either leading or lagging DA14 by the correct amount to place it in a closer approach it could have been possible for Earth’s gravity to capture it and swing it around until it eventually made a northern hemisphere impact. Again and as Ravenous pointed out, this would be unlikely but IMO still possible.

Anyways, it seems enough data is now in to rule out this possiblity.


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BillFerris
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Re: Meet DA14's little brother? new [Re: Jarad]
      #5684036 - 02/16/13 06:36 PM

This is just too big a coincidence for astrometrists not to invest the time to explore in detail the possibility that this meteoroid and DA14 are linked. I don't care what NASA's--or anyone else's--instant analysis suggests, the odds of the two such events happening on the same day are astronomical. It's much more likely that the objects are linked or related in some way.

Bill in Flag

Quote:

Ravenous nailed it. NASA has an update here. It says:

"According to NASA scientists, the trajectory of the Russian meteorite was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russian meteorite and analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14's trajectory is in the opposite direction, from south to north."

Jarad




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Ira
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Re: Meet DA14's little brother? new [Re: BillFerris]
      #5684055 - 02/16/13 06:49 PM

I'm still waiting for the third shoe to drop.

/Ira


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Ebyl
super member


Reged: 07/04/12

Re: Meet DA14's little brother? new [Re: BillFerris]
      #5684187 - 02/16/13 08:27 PM

Quote:

This is just too big a coincidence for astrometrists not to invest the time to explore in detail the possibility that this meteoroid and DA14 are linked. I don't care what NASA's--or anyone else's--instant analysis suggests, the odds of the two such events happening on the same day are astronomical. It's much more likely that the objects are linked or related in some way.




The problem with that is someone needs to provide a theory for how this would happen before anyone, including myself, will take it seriously. Everything we know right now shows the meteor over Russia was not related in any way to 2012 DA14. If you, or anyone else, can provide some evidence besides timing (which is not evidence at all because it legitimately can be chalked up to coincidence), I'm sure people will be more than happy to take a gander.


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Glassthrower
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Re: Meet DA14's little brother? new [Re: Ebyl]
      #5684196 - 02/16/13 08:38 PM

This explanation was recently posted to the Meteorite mailing list by Dr. Marco Langbroek :

Quote:



"I still see suggestions popping up on this list about a possible link between 2012 DA14 and the Russian meteor.

I want to point out that even without an accurate trajectory for the Russian bolide, a link with 2012 DA14 can be 100% rejected. The orbital geometry of 2012 DA14 and the latitude of 55 N for the Russian bolide make this impossible.

2012 DA14 and any fragments in a swarm in similar orbit, would approach the earth from deep south. The geocentric radiant for the orbit of 2012 DA14 is at declination -81 degrees. This means 2012 DA14 fragments approach earth almost parallel to the earth polar axis, coming from the south. I.e. they approach towards the south pole and the southern hemisphere.

This means fragments can impact on the southern hemisphere, but not on the northern hemisphere (except very low latitudes north if we take earth gravitational curvature of the final trajectory in account). Because the northern hemisphere, and certainly a place as far north as 55 N, is at the "far side" of the earth globe as seen from the 2012 DA14 entry direction.

Compare it with a car. A bird coming in frontal will always hit the front of the car - it cannot hit the back of the car. Chelyabinsk at 55 North latitude is "the back of the car" in this comparison, given the approach direction of 2012 DA 14 and any fragments of it."






I think that explains it pretty well.

Another list member (Chris Peterson), explained it thusly :

Quote:


It takes a large amount of energy to split a massive body into components with radically different orbits (and that these bodies have radically different orbits is known beyond reasonable doubt). That energy could be supplied explosively, as when a pair of bodies collide. But that amount of energy would create a lot of debris, which has not been observed. It is also statistically unlikely for it to occur very close to the Earth (as it would have to). Indeed, that is statistically much less likely than the simple passage of two bodies close to the Earth within a few hours of each other.

The other mechanism for creating different orbits is the actual one that describes much of what we see in terms of minor bodies in the Solar System, which is gravitational perturbation. What frequently goes unappreciated, however, is that three bodies are required. These are most often the asteroid/comet, Jupiter, and the Sun, but certainly other bodies are occasionally involved. The only potential body that could set up these different orbits so shortly before impact would be the Moon. But I don't believe that DA14 passed closely enough to the Moon to allow a tidal separation of asteroid components followed by the complex sort of "slingshot" effect that would be required to so dramatically change the inclination and velocity of the smaller component. Remember, DA14 has been under observation for a year.

So that's what I mean when I say that there seems to be no reasonable or likely scenario that could explain these bodies being related. But the odds of two such bodies being where they were at that time are not particularly long at all.





Both of those persons are very knowledgeable and my math stinks - so without checking the math, I trust their explanations.



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Ebyl
super member


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Re: Meet DA14's little brother? new [Re: Glassthrower]
      #5684220 - 02/16/13 08:52 PM

Yep, that's exactly what I'm saying. A lot of people who know what they're doing have looked at this and determined it wasn't related. Until evidence or a theory emerges to challenge that, the default assumption has to be the timing was just a coincidence.

Edited by Ebyl (02/16/13 08:53 PM)


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Qwickdraw
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Re: Meet DA14's little brother? new [Re: Glassthrower]
      #5684719 - 02/17/13 07:25 AM

Quote:


Both of those persons are very knowledgeable and my math stinks - so without checking the math, I trust their explanations.






I may not understand the whole concept but do know that given the correct mass, speed and altitude of an object you can have it swing all the way around a planet and leave orbit again, ala Apollo 13 or any number of other examples. That said, it is not hard to imagine that you can also have it approach from one hemisphere and fail to have enough escape velocity or mass and impact on the opposite hemisphere from its origin. So my point is what hemisphere it landed in should not entirely rule out that it originated from the opposite. At least this is my understanding of orbital physics.
I am not saying this is likely but only possible.

If I am wrong, please feel free to correct me.


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Mister T
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Re: Meet DA14's little brother? new [Re: Qwickdraw]
      #5684838 - 02/17/13 09:33 AM

the odds of it happening are 100% because IT HAPPENED!

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shawnhar
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Re: Meet DA14's little brother? new [Re: BillFerris]
      #5684916 - 02/17/13 10:37 AM

Quote:

This is just too big a coincidence for astrometrists not to invest the time to explore in detail the possibility that this meteoroid and DA14 are linked. I don't care what NASA's--or anyone else's--instant analysis suggests, the odds of the two such events happening on the same day are astronomical. It's much more likely that the objects are linked or related in some way.

Bill in Flag




Consider this...There were 2 babies born yesterday, each with 6 fingers on the right hand, within hours of each other. One in China and one in Argentina. This defect is exceedingly rare, les than one in 10 million births.
Are they related?


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Mister T
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Re: Meet DA14's little brother? new [Re: shawnhar]
      #5684952 - 02/17/13 10:56 AM

Not if they are aliens babies from the ship that landed in Russia!!

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Qwickdraw
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Re: Meet DA14's little brother? new [Re: shawnhar]
      #5685150 - 02/17/13 12:45 PM

Quote:

Quote:

This is just too big a coincidence for astrometrists not to invest the time to explore in detail the possibility that this meteoroid and DA14 are linked. I don't care what NASA's--or anyone else's--instant analysis suggests, the odds of the two such events happening on the same day are astronomical. It's much more likely that the objects are linked or related in some way.

Bill in Flag




Consider this...There were 2 babies born yesterday, each with 6 fingers on the right hand, within hours of each other. One in China and one in Argentina. This defect is exceedingly rare, les than one in 10 million births.
Are they related?




I dont know if they are related, you failed to point out who the parents are and we would have to trace the family tree.

Edited by Qwickdraw (02/17/13 05:37 PM)


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BillFerris
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Re: Meet DA14's little brother? new [Re: shawnhar]
      #5685168 - 02/17/13 12:55 PM

Polydactyly (many fingers or toes) is considered a common congenital defect and occurs in 1 out of 500 to 1,000 births in the United States. Given that 450,000 and 500,000 newborns enter the world population each day, odds are 500 to 1,000 babies are born each day with polydactyly. Check out the Boston Children's Hospital website for more information on available treatments of this common defect.

How is a human congenital birth defect analagous to the incidence of large meteoroidal or small asteroidal bodies hitting or passing near Earth?

Bill in Flag

Quote:

Quote:

This is just too big a coincidence for astrometrists not to invest the time to explore in detail the possibility that this meteoroid and DA14 are linked. I don't care what NASA's--or anyone else's--instant analysis suggests, the odds of the two such events happening on the same day are astronomical. It's much more likely that the objects are linked or related in some way.

Bill in Flag




Consider this...There were 2 babies born yesterday, each with 6 fingers on the right hand, within hours of each other. One in China and one in Argentina. This defect is exceedingly rare, les than one in 10 million births.
Are they related?




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llanitedave
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Re: Meet DA14's little brother? new [Re: BillFerris]
      #5686046 - 02/17/13 09:50 PM

I don't know if polydactyly is a good example or not, but it's worth mentioning that our ability to detect close encounters with small objects is very new. Because most of these, like the Russian object, explode in Earth's atmosphere and/or end up in the oceans rather than causing craters, we really have no good estimates of their impact frequency. There will obviously be far more near misses than there are impacts.

The lesson to take away isn't so much that this is an almost inconceivably unlikely coincidence, but that close approaches and physical impacts with small bodies are a lot more common than we used to think.


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Scott Horstman
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Re: Meet DA14's little brother? new [Re: llanitedave]
      #5686064 - 02/17/13 10:02 PM

There was a smaller one on the west coast that evening as well.

http://www.washingtonpost.com/national/health-science/on-heels-of-russia-mete...


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Glassthrower
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Re: Meet DA14's little brother? new [Re: Scott Horstman]
      #5686123 - 02/17/13 10:45 PM

What I find a little disconcerting is that the Russian object slipped through undetected, despite hundreds of telescopes being pointed skyward for a month prior while tracking DA14. The Russian object, despite having the power to destroy a city the size of Chicago (had the airburst happened much closer to ground level), falls below the size-threshold for detection using our current observing networks. This needs to be remedied.

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Scott Horstman
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Re: Meet DA14's little brother? new [Re: Glassthrower]
      #5686169 - 02/17/13 11:16 PM

It's estimated that there are probably 500,000 NEOs the size of DA14 or larger and about 1% of that have been discovered. How many of the smaller ones that can do damage are there?
If it's any consolation, at least we're finding a lot of the bigger ones.

http://www.youtube.com/watch?v=skWA0wg3vZk


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Ebyl
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Re: Meet DA14's little brother? new [Re: Scott Horstman]
      #5686390 - 02/18/13 02:58 AM

Keep in mind that a meteor like the one over Russia has almost no chance of getting anywhere close to the ground. I'm not even sure what scenario would cause one like it, and of similar size, to "explode" near the ground, let alone reach it. And chondrites make up about 85% of all meteorites found, so we know they're by far the most common.

My point here is that while meteors of this size and a bit smaller certainly pack enough energy to cause considerable damage (500kt is a scary number at first glance), since the majority are chondrites they will not get the chance. Now, an iron or stony iron meteoroid might be a different story. But they are much, much rarer - something like 5-6% of meteorites found, I think.

I would also say I think we are getting a good grasp of how often these types of events happen. Infrasound detectors have incredible ranges, so I doubt any event of significant size escapes their notice. And that's to say nothing about things like satellite and radar detection of meteor events. Of course, that's only useful for the smaller meteoroids, since the larger ones are so infrequent as to require study by whatever impact craters we can find.

In the end, while I think we'd be well served with an increased push in detection efforts, I'm not sure the cost to benefit ratio is there for asteroids of this size. They are insanely difficult to detect and the vast majority would never cause any significant damage. I don't think the picture is quite as grim as the numbers appear on the surface.


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Jarad
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Re: Meet DA14's little brother? new [Re: Qwickdraw]
      #5686636 - 02/18/13 09:10 AM

Quote:

I may not understand the whole concept but do know that given the correct mass, speed and altitude of an object you can have it swing all the way around a planet and leave orbit again, ala Apollo 13 or any number of other examples.




The issue is the speed. Both objects were coming in at high speed, well above orbital velocity. So while the earth's gravity could have deflected their orbit a little bit around the equator, not that far north. And certainly not that far north and heading south (a full 180 degree reversal).

Again, I gave Ravenous props because he noticed the correct issue, even before the additional info about the actual heading of the bolide.

Jarad


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Re: Meet DA14's little brother? new [Re: BillFerris]
      #5687098 - 02/18/13 03:04 PM

Sorry Bill, I meant the rare form of fully functioning no correction needed extra digits.
My point was that just because 2 rare events happen within a short timeframe doesn't mean they are related. (Unless the event repeats) I will concede that some event(s) in the asteroid belt could have led the close timing, but we don't have any evidence for that, in fact the evidence leads away from that supposition. These 2 events are related in the way that every movement in the solar system is gravitationaly affected by everything else but I don't think we will find direct interactions leading to these 2 visitors arriving so close in time.


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Re: Meet DA14's little brother? new [Re: shawnhar]
      #5687302 - 02/18/13 04:52 PM

Interesting. Looks as if there may have been another one off the Florida coast.

http://www.miamiherald.com/2013/02/17/3240318/ball-of-light-flashes-over-sout...


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Re: Meet DA14's little brother? new [Re: Qwickdraw]
      #5688459 - 02/19/13 08:31 AM

Quote:

I may not understand the whole concept but do know that given the correct mass, speed and altitude of an object you can have it swing all the way around a planet and leave orbit again, ala Apollo 13 or any number of other examples.



Actually you are right in theory - has anybody mentioned aerobraking yet? (The technique Apollo used very accurately to save a vast amount of fuel.) The smaller meteor could have barely skimmed the atmosphere hours or days before, in some uninhabited location, going straight through but at a lower speed. With enough speed lost, it could have been recaptured before re-entering.

That probably didn't happen though, as (a) it's fantastically unlikely (b) the deceleration in the first pass would probably have shattered it, in the way that was seen on the day and (c) if the speed observed over Russia is over a certain value it was never in a captured orbit anyway. (I don't think any of it happened, I'm just mentioning this to see if I can start an internet myth!)

Quote:

That said, it is not hard to imagine that you can also have it approach from one hemisphere and fail to have enough escape velocity or mass and impact on the opposite hemisphere from its origin.




There's another idea - we (well NASA) frequently use close passes to boost the speed of a probe - the "slingshot". I wonder what geometry would be needed to cause the reverse and reduce speed, and IF it's practical. (Planets have captured moons on occasion.) Though it might not work on something on DA14's path as it's far out of plane...?


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Jarad
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Re: Meet DA14's little brother? new [Re: Ravenous]
      #5688472 - 02/19/13 08:41 AM

Quote:

There's another idea - we (well NASA) frequently use close passes to boost the speed of a probe - the "slingshot". I wonder what geometry would be needed to cause the reverse and reduce speed, and IF it's practical. (Planets have captured moons on occasion.) Though it might not work on something on DA14's path as it's far out of plane...?




This one is easy - to gain velocity via slingshot, you have your probe approach the planet from ahead of it in it's orbit. It swings in close and goes back out at the nearly same speed relative to the planet, but since it came from ahead of the planet it can gain up to 2x the planet's orbital velocity. In the simplest scenario, the probe is sitting still as the planet approaches at orbital velocity, it slingshots around the planet and ends up moving ahead of the planet by the same velocity (at orbital velocity relative to the planet, so now at 2x orbital velocity relative to the sun).

To lose speed, you have it approach from behind the planet in its orbit. Again, in the simplest form the probe comes up from behind at 2x the orbital velocity, for a relative velocity equal to orbital velocity. It swings around and leaves at orbital velocity relative to the planet, but now is sitting still relative to the sun.

Jarad


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Re: Meet DA14's little brother? new [Re: Scott Horstman]
      #5688828 - 02/19/13 12:40 PM

Quote:

Interesting. Looks as if there may have been another one off the Florida coast.

http://www.miamiherald.com/2013/02/17/3240318/ball-of-light-flashes-over-sout...




Cuban meteor video
"Cosmic coincidence: Watch a SECOND meteor in the sky 6,000 miles from Russian space rock crash"

http://www.mirror.co.uk/news/weird-news/second-meteor-video-cuba-two-1712957#...

"Cuba, too, reports powerful meteorite explosion"

http://www.sfgate.com/news/science/article/Cuba-too-reports-powerful-meteorit...

The other coincidence is, Cienfuegos means 100 fires .

Jason W. Higley


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Glassthrower
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Re: Meet DA14's little brother? new [Re: Jason H.]
      #5688852 - 02/19/13 12:53 PM

Last thing I heard, the Cuba fireball was the real deal and was a good candidate to drop meteorites. But, Cuba is not a friendly environment for meteorite hunting.....for a variety of reasons, both political and logistical.

Ditto for a recent fireball seen over southern Florida, but that one plotted to drop it's payload (if any) over the ocean.

The Cuban meteorites (if any) may also be sitting at the bottom of the sea.


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Scott Horstman
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Re: Meet DA14's little brother? new [Re: Glassthrower]
      #5689157 - 02/19/13 04:00 PM

Here's a question for you guys.

Why would you suppose the Russian, San Fran and Cuban meteors all were more or less "grazers", coming in on a very shallow angle rather than coming in straight down?
Earth is nearly an 8000 mile target. Why would they so commonly graze the edge?


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Jarad
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Re: Meet DA14's little brother? new [Re: Scott Horstman]
      #5689233 - 02/19/13 04:34 PM

I don't think we are assuming that. Grazing came up as one way to try allow an object coming from the south to hit in the north (i.e. a first grazing pass to lose velocity, allowing it to swing around on the second pass). But it was presented as an extremely unlikely scenario, not what we actually think happened.

For actual impacts, if we assume the incoming trajectory is essentially random, the odds are slightly higher for lower angles of entry than higher angles. Look at the earth as a target, coming in straight down is the bullseye. The rings going out are progressively shallower entry angles, since the earth is a sphere not a flat circle. There is more cross-sectional area in the outer rings than the inner ones, so most hits will be at 45 degrees or less. Only bullseyes will come in at 90 degrees. But there will be a distribution of all entry angles, just more frequent for lower angles.

Jarad


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Scott Horstman
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Re: Meet DA14's little brother? new [Re: Jarad]
      #5689442 - 02/19/13 06:29 PM

Good point Jarad, I didn't look at it like that. It makes sense that probably 2/3 of meteors have a chance of entering at less than 45 degrees.

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Glassthrower
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Re: Meet DA14's little brother? new [Re: Jarad]
      #5689459 - 02/19/13 06:40 PM

FWIW, for those who are having fun recreating this event using impact simulators, consider this single statistic - in the 21st century, we have only one known iron meteorite that was recovered - the Kavarpura anomalous iron meteorite that fell over Rajasthan India on August 29, 2006.

In comparison, stony meteorites (chondritic and achondritic) have accounted for 85 recovered falls.

In a little over 13 years, we have had 86 total known meteorite falls. Only one of which was an iron.

The Kavarpura iron meteorite was a single recovered mass of less than 7 kilograms and didn't cause any destruction. I do not know it's size before it entered the atmosphere, went through the process of ablation, and then hit the ground as a grapefruit-sized, regmaglypted mass. The only possible sign of it's fall may have been a tiny dent or impact pit in the target ground that would not qualify to be called a "crater".

The term "city killer" comes into play with BIG iron bodies that come in just the right way and do not explode high in the atmosphere.

As was said earlier by someone else, a stony meteorite often does not survive the stresses atmospheric entry and they disrupt or explode much sooner and farther from the ground - producing an impressive visual display and one heck of a shockwave, but little relative damage on the ground.

This is what happened with the Chebarkul event - the angle of entry, speed of entry, the size of the body, and the composition of the body resulted in a cosmic starter pistol shot. It was loud, it got everyone's attention, but it was harmless in the grand scheme of potential impactors. Or to use the more popular analogy - this was a shot across our bow.

Play with the numbers in the simulator a little bit and you get a much deadlier result from a similar sized body of a different composition that enters our atmosphere at a higher velocity and at a more extreme/vertical angle.

This Russian meteorite could have been a Canyon Diablo crater-maker. Or Chicxulub. We should be able to detect the "planet killers" at a greater distance, but the so-called "city killers" can be frightfully small and hard to detect before it's too late. We need improvements in our detection systems.

We've had 86 warnings in the last 13+ years. This was the biggest and most damaging one since Tunguska, and we would be wise to continue improving our monitoring systems and perhaps accelerate the pace of that improvement. It's not being paranoid, it's being prudent.

Best regards and clear dark (and safer) skies,

MikeG


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llanitedave
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Re: Meet DA14's little brother? new [Re: Jarad]
      #5690059 - 02/20/13 12:48 AM

Quote:

Quote:

There's another idea - we (well NASA) frequently use close passes to boost the speed of a probe - the "slingshot". I wonder what geometry would be needed to cause the reverse and reduce speed, and IF it's practical. (Planets have captured moons on occasion.) Though it might not work on something on DA14's path as it's far out of plane...?




This one is easy - to gain velocity via slingshot, you have your probe approach the planet from ahead of it in it's orbit. It swings in close and goes back out at the nearly same speed relative to the planet, but since it came from ahead of the planet it can gain up to 2x the planet's orbital velocity. In the simplest scenario, the probe is sitting still as the planet approaches at orbital velocity, it slingshots around the planet and ends up moving ahead of the planet by the same velocity (at orbital velocity relative to the planet, so now at 2x orbital velocity relative to the sun).

To lose speed, you have it approach from behind the planet in its orbit. Again, in the simplest form the probe comes up from behind at 2x the orbital velocity, for a relative velocity equal to orbital velocity. It swings around and leaves at orbital velocity relative to the planet, but now is sitting still relative to the sun.

Jarad




I think that's backwards, Jarad. Every diagram I've ever seen, and every gravitational simulation I've done, increases the passing body's energy when it approaches from behind the orbital path of the larger planet. Here's a typical example.

The trick is that the probe (or asteroid) are both going in the same direction relative to the Sun, the larger planet pulling the small trailing probe towards it means that the probe gains much more velocity in the direction of its orbit around the Sun than the planet loses. If it passes in front of the planet, it's pulled back in velocity relative to the Sun.

The best way for it to be captured is for its perihelion to be just inside the orbit of the planet, so it's at the slow point of its velocity just as the planet catches up. There are other ways, but they involve more complex motions and often multiple encounters.

Of course, if the probe is in a retrograde orbit, that's a whole 'nother issue.


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Jarad
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Re: Meet DA14's little brother? new [Re: llanitedave]
      #5690290 - 02/20/13 07:35 AM

Quote:


I think that's backwards, Jarad. Every diagram I've ever seen, and every gravitational simulation I've done, increases the passing body's energy when it approaches from behind the orbital path of the larger planet. Here's a typical example.




We are saying the same thing, just mis-communicating about reference frames. The probe leaves going in roughly the opposite direction it approached from, relative to the planet. To gain speed, it comes in from in front of the planet, swings around behind it, and leaves going out ahead of it again. The closest point where it swings around is on the opposite side that it approached from.

For the slingshot boost scenario, they will usually both be going in the same direction relative to the sun, but the probe is going slower at first (so in the planet's reference frame, it is coming towards the planet from in front of it in orbit). After the swing, they are both going in the same direction, but the probe has picked up speed (in the planet's frame, the probe did a U-turn around the planet and is now headed in the opposite direction it started in).

Of course, that's the most extreme example. In reality, it will be a hyperbola, not a perfect U. More of a V with a curved bottom. If the open end of the V points forward in the planet's orbit, then the probe gains speed. If the open end points backward, it loses speed. By angling the V relative to the orbit, you can also change direction as well as speed (and of course in orbital mechanics changing speed cause a change in direction anyway...).

It only looks like a U in the planet's reference frame. From the sun's reference frame (how the diagram in the link is drawn) it looks much wider, since both objects are moving forward while the probe swings around the planet.

Jarad

Edited by Jarad (02/20/13 03:52 PM)


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Glassthrower
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Re: Meet DA14's little brother? new [Re: Jarad]
      #5690483 - 02/20/13 09:43 AM

Jarad, Dave, and others :

I am glad you guys are here for the parts of this that make my head explode. I can imagine the details once you fine gentlemen explain the mathematics and dynamics at work. I am completely right-brained and have little grasp of numbers. Without the explanations you offer here, I'd just be imagining rocks hitting a windshield with little understanding of how.

Just wanted to say thanks for that.

Best regards,

MikeG


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Dave Mitsky
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Re: Meet DA14's little brother? new [Re: Glassthrower]
      #5691161 - 02/20/13 03:33 PM

Regmaglypted, now there's a word that you don't see everyday.

http://www.answers.com/topic/regmaglypt

Dave Mitsky


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llanitedave
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Re: Meet DA14's little brother? new [Re: Jarad]
      #5691833 - 02/20/13 10:02 PM

Quote:

Quote:


I think that's backwards, Jarad. Every diagram I've ever seen, and every gravitational simulation I've done, increases the passing body's energy when it approaches from behind the orbital path of the larger planet. Here's a typical example.




We are saying the same thing, just mis-communicating about reference frames. The probe leaves going in roughly the opposite direction it approached from, relative to the planet. To gain speed, it comes in from in front of the planet, swings around behind it, and leaves going out ahead of it again. The closest point where it swings around is on the opposite side that it approached from.

For the slingshot boost scenario, they will usually both be going in the same direction relative to the sun, but the probe is going slower at first (so in the planet's reference frame, it is coming towards the planet from in front of it in orbit). After the swing, they are both going in the same direction, but the probe has picked up speed (in the planet's frame, the probe did a U-turn around the planet and is now headed in the opposite direction it started in).

Of course, that's the most extreme example. In reality, it will be a hyperbola, not a perfect U. More of a V with a curved bottom. If the open end of the V points forward in the planet's orbit, then the probe gains speed. If the open end points backward, it loses speed. By angling the V relative to the orbit, you can also change direction as well as speed (and of course in orbital mechanics changing speed cause a change in direction anyway...).

It only looks like a U in the planet's reference frame. From the sun's reference frame (how the diagram in the link is drawn) it looks much wider, since both objects are moving forward while the probe swings around the planet.

Jarad




Ok, I was looking at a Sun-centered frame of reference, and you were looking at the planet-centered one. I guess the critical item is that the closest approach (if we're looking for a slingshot effect, anyway) must occur on the trailing side of the planet relative to its orbit around the Sun.

It can get a bit more complicated, because a fast-moving object can overtake the planet from the trailing side and, under certain conditions, be boosted still further, as long as the overtaking direction is still oblique relative to the Sun. That would be a case where the planet-centered perspective would not see the object approaching from the forward side, but would still see it departing that way.


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Re: Meet DA14's little brother? new [Re: Glassthrower]
      #5691857 - 02/20/13 10:17 PM

Quote:

Jarad, Dave, and others :

I am glad you guys are here for the parts of this that make my head explode. I can imagine the details once you fine gentlemen explain the mathematics and dynamics at work. I am completely right-brained and have little grasp of numbers. Without the explanations you offer here, I'd just be imagining rocks hitting a windshield with little understanding of how.

Just wanted to say thanks for that.

Best regards,

MikeG




You can do this at home. And you don't have to be a math genius.

Years ago I used the code on this web site to construct a toy gravitational simulator in javascript.

It's "toy" in that it's relatively slow and that it only handles a few bodies at a time, but the calculations are rigorous and the gravitational interactions are correct. All I had to do was change the code from C to javascript and adapt it to a GUI for my browser.

I spent hours playing with different setups and watching it run. OK, a "normal" person might have found that kind of project tedious, but I was spending 3 hours a day on a bus commute and tedium was unavoidable. Anyway, you watch these kinds of things happen long enough, and the visualization starts to become intuitive.

And your friends start questioning your sanity.


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Glassthrower
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Re: Meet DA14's little brother? new [Re: llanitedave]
      #5699421 - 02/25/13 08:45 AM

Chebarkul-Chelyabinsk is an Apollo!

http://www.technologyreview.com/view/511691/astronomers-calculate-orbit-of-ch...

More accurate numbers have come in since this article was written, and an updated orbit is being calculated now.


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Glassthrower
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Re: Meet DA14's little brother? new [Re: Glassthrower]
      #5699888 - 02/25/13 01:53 PM

Interestingly, DA14's recent pass altered it's orbit sufficiently that it has been reclassified as an Aten class object, instead of an Apollo.

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Achernar
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Re: Meet DA14's little brother? new [Re: Glassthrower]
      #5700531 - 02/25/13 08:32 PM

That makes this asteroid more hazardous because of the fact it will for the foreseeable futre spend most of it's time inside Earth's orbit around the Sun. That makes it hard to see, and therefore creates a possibilility it could come at us hidden in the glare of the Sun. By the time we realize it's coming, it could have already hit us just like Chelyabinsk Russia or Tunguska.

Taras


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groz
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Re: Meet DA14's little brother? new [Re: Achernar]
      #5716386 - 03/06/13 01:25 PM

I haven't done any math on it (yet), been to busy, but, there are plenty of scenarios that can link the two events, and account for the discrepancies in direction. To really nail it, one needs to know the velocity and trajectory of the impactor, prior to entering atmosphere, and that data wont ever be available. There are estimates, with some likely bounds, but, accurate data isn't going to come forth.

One thing I notice in most analysis, folks are treating this as a one body problem, when in fact, it isn't. Earth - Moon system is a two body system, and, if the leading chunk of debris had a close lunar encounter, velocity and trajectory could possibly appear entirely divergent from the trailing piece. I'm sure one can grind up the numbers and find a set of values to fit a solution that shows leading piece interacting with luna, and departing that interaction on a trajectory that impacts in russia.

Probabilities of such an encounter are probably astronomical, but, not any more astronomical than the two events being totally uncorrelated.

I'm with bill in flag on this one, a close encounter and an impact on the same day, I wouldn't be so quick to dismiss, but instead, look hard for a possible way to reconcile the apparently differing trajectories.


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Jarad
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Re: Meet DA14's little brother? new [Re: groz]
      #5716556 - 03/06/13 02:33 PM

Quote:

I'm sure one can grind up the numbers and find a set of values to fit a solution that shows leading piece interacting with luna, and departing that interaction on a trajectory that impacts in russia.




Actually, I doubt that. Remember, DA14 was moving south to north. The moon orbits in the same plane that the earth rotates. So you would have to have the object pass the moon going north and swing almost 90 degrees to head towards earth's northern hemisphere. I don't think the moon has enough mass to swing an object moving as fast as both of these were that much.

Jarad


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Re: Meet DA14's little brother? new [Re: Jarad]
      #5716752 - 03/06/13 04:15 PM



Closeup of the Russian asteroid.. You can see the plasma rolling off the rock..

High velocity and air friction = HOT!



http://www.youtube.com/watch?v=4MK5VO9HAjs


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Glassthrower
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Re: Meet DA14's little brother? new [Re: StarWars]
      #5717228 - 03/06/13 08:33 PM

Quote:


Closeup of the Russian asteroid.. You can see the plasma rolling off the rock..

High velocity and air friction = HOT!



http://www.youtube.com/watch?v=4MK5VO9HAjs






Just a quick heads-up. This video has been debunked. It is an older unrelated video of a missile test. It fooled me at first also. I saw an edited version that was shorter and only showed the zoomed sections, and the larger context was deleted out. But, it's actually an old video of a Russian missile test.

Best regards,

MikeG


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Re: Meet DA14's little brother? new [Re: Jarad]
      #5717406 - 03/06/13 10:19 PM

Quote:

Quote:

I'm sure one can grind up the numbers and find a set of values to fit a solution that shows leading piece interacting with luna, and departing that interaction on a trajectory that impacts in russia.




Actually, I doubt that. Remember, DA14 was moving south to north. The moon orbits in the same plane that the earth rotates. So you would have to have the object pass the moon going north and swing almost 90 degrees to head towards earth's northern hemisphere. I don't think the moon has enough mass to swing an object moving as fast as both of these were that much.

Jarad




Absolutely. The types of gravitational gyrations required to separate two bodies into two different trajectories in such a way require far more pinpoint timing than a simple coincidental set of independent encounters do.

I think Occam has this one covered.


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StarWars
Mr. Postmaster Man
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Reged: 11/26/03

Loc: At the Gym >Spudtastic<
Re: Meet DA14's little brother? new [Re: Glassthrower]
      #5717658 - 03/07/13 02:16 AM

Quote:

Quote:


Closeup of the Russian asteroid.. You can see the plasma rolling off the rock..

High velocity and air friction = HOT!



http://www.youtube.com/watch?v=4MK5VO9HAjs






Just a quick heads-up. This video has been debunked. It is an older unrelated video of a missile test. It fooled me at first also. I saw an edited version that was shorter and only showed the zoomed sections, and the larger context was deleted out. But, it's actually an old video of a Russian missile test.

Best regards,

MikeG








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Glassthrower
Vendor - Galactic Stone & Ironworks
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Re: Meet DA14's little brother? new [Re: StarWars]
      #5718928 - 03/07/13 05:43 PM

Don't feel bad Rich, I know one planetary scientist who shall remain unnamed, who was also fooled briefly by that same video. It made me feel a little better when I heard that.

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deSitter
Still in Old School


Reged: 12/09/04

Re: Meet DA14's little brother? new [Re: llanitedave]
      #5720041 - 03/08/13 08:50 AM

Quote:

Quote:

Jarad, Dave, and others :

I am glad you guys are here for the parts of this that make my head explode. I can imagine the details once you fine gentlemen explain the mathematics and dynamics at work. I am completely right-brained and have little grasp of numbers. Without the explanations you offer here, I'd just be imagining rocks hitting a windshield with little understanding of how.

Just wanted to say thanks for that.

Best regards,

MikeG




You can do this at home. And you don't have to be a math genius.

Years ago I used the code on this web site to construct a toy gravitational simulator in javascript.

It's "toy" in that it's relatively slow and that it only handles a few bodies at a time, but the calculations are rigorous and the gravitational interactions are correct. All I had to do was change the code from C to javascript and adapt it to a GUI for my browser.

I spent hours playing with different setups and watching it run. OK, a "normal" person might have found that kind of project tedious, but I was spending 3 hours a day on a bus commute and tedium was unavoidable. Anyway, you watch these kinds of things happen long enough, and the visualization starts to become intuitive.

And your friends start questioning your sanity.




I've gotten some of my best work done on bus commutes! I spent endless hours investigating Clifford algebras on a TI92+ calculator

-drl


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