Jump to content


Photo

Meet DA14's little brother?

  • Please log in to reply
68 replies to this topic

#26 BillFerris

BillFerris

    Soyuz

  • *****
  • Posts: 3687
  • Joined: 17 Jul 2004
  • Loc: Flagstaff, Arizona, USA

Posted 16 February 2013 - 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

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



#27 Ira

Ira

    Mercury-Atlas

  • *****
  • Posts: 2633
  • Joined: 22 Aug 2010
  • Loc: Mitzpe Ramon, Israel

Posted 16 February 2013 - 06:49 PM

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

/Ira

#28 Ebyl

Ebyl

    Vostok 1

  • -----
  • Posts: 124
  • Joined: 04 Jul 2012

Posted 16 February 2013 - 08:27 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.


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.

#29 Glassthrower

Glassthrower

    Vendor - Galactic Stone & Ironworks

  • *****
  • Vendors
  • Posts: 18367
  • Joined: 07 Apr 2005
  • Loc: Oort Cloud 9

Posted 16 February 2013 - 08:38 PM

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


"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 :

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.

:)

#30 Ebyl

Ebyl

    Vostok 1

  • -----
  • Posts: 124
  • Joined: 04 Jul 2012

Posted 16 February 2013 - 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.

#31 Qwickdraw

Qwickdraw

    Surveyor 1

  • *****
  • Posts: 1729
  • Joined: 03 Mar 2012
  • Loc: Ann Arbor, MI

Posted 17 February 2013 - 07:25 AM

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.


#32 Mister T

Mister T

    Apollo

  • -----
  • Posts: 1324
  • Joined: 01 Feb 2008
  • Loc: Upstate NY

Posted 17 February 2013 - 09:33 AM

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

#33 shawnhar

shawnhar

    Fly Me to the Moon

  • *****
  • Posts: 5750
  • Joined: 25 Jun 2010
  • Loc: Knoxville, TN

Posted 17 February 2013 - 10:37 AM

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?

#34 Mister T

Mister T

    Apollo

  • -----
  • Posts: 1324
  • Joined: 01 Feb 2008
  • Loc: Upstate NY

Posted 17 February 2013 - 10:56 AM

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

#35 Qwickdraw

Qwickdraw

    Surveyor 1

  • *****
  • Posts: 1729
  • Joined: 03 Mar 2012
  • Loc: Ann Arbor, MI

Posted 17 February 2013 - 12:45 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

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. :grin:

#36 BillFerris

BillFerris

    Soyuz

  • *****
  • Posts: 3687
  • Joined: 17 Jul 2004
  • Loc: Flagstaff, Arizona, USA

Posted 17 February 2013 - 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

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?



#37 llanitedave

llanitedave

    Humble Megalomaniac

  • *****
  • Posts: 22580
  • Joined: 25 Sep 2005
  • Loc: Amargosa Valley, NV, USA

Posted 17 February 2013 - 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.

#38 Scott Horstman

Scott Horstman

    Vendor - Backyard Observatories

  • *****
  • Vendors
  • Posts: 14584
  • Joined: 11 Mar 2004
  • Loc: Here, There and Everywhere

Posted 17 February 2013 - 10:02 PM

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

http://www.washingto...-russia-mete...

#39 Glassthrower

Glassthrower

    Vendor - Galactic Stone & Ironworks

  • *****
  • Vendors
  • Posts: 18367
  • Joined: 07 Apr 2005
  • Loc: Oort Cloud 9

Posted 17 February 2013 - 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.

#40 Scott Horstman

Scott Horstman

    Vendor - Backyard Observatories

  • *****
  • Vendors
  • Posts: 14584
  • Joined: 11 Mar 2004
  • Loc: Here, There and Everywhere

Posted 17 February 2013 - 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.c...h?v=skWA0wg3vZk

#41 Ebyl

Ebyl

    Vostok 1

  • -----
  • Posts: 124
  • Joined: 04 Jul 2012

Posted 18 February 2013 - 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.

#42 Jarad

Jarad

    Fly Me to the Moon

  • *****
  • Posts: 6387
  • Joined: 28 Apr 2003
  • Loc: Atlanta, GA

Posted 18 February 2013 - 09:10 AM

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

#43 shawnhar

shawnhar

    Fly Me to the Moon

  • *****
  • Posts: 5750
  • Joined: 25 Jun 2010
  • Loc: Knoxville, TN

Posted 18 February 2013 - 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.

#44 Scott Horstman

Scott Horstman

    Vendor - Backyard Observatories

  • *****
  • Vendors
  • Posts: 14584
  • Joined: 11 Mar 2004
  • Loc: Here, There and Everywhere

Posted 18 February 2013 - 04:52 PM

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

http://www.miamihera...es-over-sout...

#45 Ravenous

Ravenous

    Viking 1

  • -----
  • Posts: 607
  • Joined: 14 Nov 2009
  • Loc: UK

Posted 19 February 2013 - 08:31 AM

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 © 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!)

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...?

#46 Jarad

Jarad

    Fly Me to the Moon

  • *****
  • Posts: 6387
  • Joined: 28 Apr 2003
  • Loc: Atlanta, GA

Posted 19 February 2013 - 08:41 AM

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

#47 Jason H.

Jason H.

    Apollo

  • -----
  • Posts: 1444
  • Joined: 23 Nov 2007
  • Loc: Central Florida

Posted 19 February 2013 - 12:40 PM

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

http://www.miamihera...es-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...two-1712957#...

"Cuba, too, reports powerful meteorite explosion"

http://www.sfgate.co...ful-meteorit...

The other coincidence is, Cienfuegos means 100 fires :dabomb: :dabomb: :dabomb:.

Jason W. Higley

#48 Glassthrower

Glassthrower

    Vendor - Galactic Stone & Ironworks

  • *****
  • Vendors
  • Posts: 18367
  • Joined: 07 Apr 2005
  • Loc: Oort Cloud 9

Posted 19 February 2013 - 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.


#49 Scott Horstman

Scott Horstman

    Vendor - Backyard Observatories

  • *****
  • Vendors
  • Posts: 14584
  • Joined: 11 Mar 2004
  • Loc: Here, There and Everywhere

Posted 19 February 2013 - 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?

#50 Jarad

Jarad

    Fly Me to the Moon

  • *****
  • Posts: 6387
  • Joined: 28 Apr 2003
  • Loc: Atlanta, GA

Posted 19 February 2013 - 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






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics