[meteorite-list] 2012 DA14 and the Russian meteor: a strong link

From: Marco Langbroek <marco.langbroek_at_meteoritecentral.com>
Date: Sun, 17 Feb 2013 11:29:29 +0100
Message-ID: <5120B109.1040405_at_online.nl>

Hi Bjorn, (others)

First of all, since you trump the "NASA are the experts and way more educated"
card in an absurd way: NASA is not the only organisation who has educated
experts and they do sometimes miss the obvious. Remember that "fireball over
Wales" that was not a fireball?

I have discovered 60 asteroids myself, including a NEA, and I am currently
involved in a small scale but professional asteroid search project (the Konkoly
survey, MPC 461). I am peer-reviewed published on meteors. So I am not exactly a
"nobody" in this field: I know my orbital mechanics. You have to, to discover
asteroids. I hate dick challenges, but in response to the agressive and
denigrating way you tried to question my expertise, I am tempted to ask you:
"how many asteroids did YOU discover?"

Second, and more to the point: it is you who is flat out wrong. Calculate the
2012 DA14 encounter geometry and you will see that the *combined* vector of
earth orbital movement and asteroid orbital movement (you on the other hand only
look at the asteroids' orbital movement, and that is your mistake) creates an
approach point which, seen form the geocenter, is at declination -81 degrees,
i.e. almost near the southern celestial pole.

Which means that the asteroid (and any fragments in similar orbits dispersed
around it) comes in from deep south under an angle of only 9 degrees with the
Earth's POLAR axis. It is for this reason that 2012 DA14 last Friday was visible
from the southern hemisphere first, and from the northern hemisphere only later,
moving from deep southern celestial declinations to the north.

So you are "flat out wrong", not me. For the reasons I outlined in my earlier
mail and above, fragments of a swarm in the orbit of 2012 DA14 can *never*
impact at 55 north latitude as most of the northern hemisphere represents the
"far side" of the earth as seen from the 2012 DA14 approach direction. It is a
reason similar to that why people in Australia cannot observe the Perseid meteor
shower: they are in the wrong hemisphere as seen from the approach direction of
the meteoroids.

There are multiple ways to approach such an association problem. The classic way
is to compare the bolide's trajectory with what you expect for fragments of the
asteroid. That is what NASA seems to focus on.

But in this particular case, the characteristics of the 2012 DA14 orbital
geometry also provide a clear argument, and knowing the encounter geometry of
the asteroid made this immediately very clear to me.

The point is that the bolides latitude of impact and the approach geometry of
2012 DA14 are very well established facts, even if the bolides' trajectory is
perhaps not. That is the fun of this all: in this case you don't need the
bolides trajectory, only the impact latitude and the 2012 DA14 encounter
geometry, to 100% rule out that this was 2012 DA14 related.

- Marco Langbroek




> Bjorn Sorheim
> Sent: Saturday, February 16, 2013 5:53 PM
> To: meteorite-list at meteoritecentral.com
> Subject: Re: [meteorite-list] 2012 DA14 and the Russian meteor: a strong link
>
> Hello List,
> I can't see in any way how your statements can be true, and I wonder
> how anyone can. I would assume NASA has way more educated
> professionals in this than you. Why do they say: 'Preliminary information
> indicates ---
> not related'? They would have been able to refute a strike for all areas of
> Russia according
> to your reasoning.
>
> When an asteroid having a shallow inclination of 10 deg to the ecliptical
> plane,
> that is Earth's orbital plane, and a fragment originating from this,
> travelling parallell
> to this, as I assume the meteorid/asteroid that came down near Chelyabinsk
> did, it will easily hit ANY part of Earth provided it hits when that part
> of Earth is
> facing towards it.
> Giving a large number of objects in a swarm around/forwards/backwards of
> it, these
> fragments from asteroid 2012DA14 will get to ground on all parts of the
> Earth as the Earth
> rotates through the day and night, that should be obvious.
>
> On a psychological note, I observe that none of you have countered any
> given sentence I
> have written on this russian meteor.
> You just manically keep reiterating that they are not related. I can only sea
> anxiety behind this.
>
> Sorry, Marco, but you are flatly wrong here. Your statement is absurd.
> Only asteroids with very high inclination of 70-90 degree would behave the
> way you say here.
> We are talking 10 degrees in this case, and your statements are ridiculous
> and shocking.
> You seem to believe that the orbit of 2012DA14 is retrograde, which of
> course it is not.
>
> So please, if you can prove me wrong on any sentence or statement I have
> written, do it.
> But please, Marco, Rob and Chris do it also internally to the other members
> of your
> internal group, and don't behave like a pack of wolves...
>
> I hope also when someone are putting forwards a clearly wrong statement,
> me or anyone else are allowed to denounce that statement from the person. I
> hope we can do so,
> also with a degree of engagement and temperament. I say this also to the
> other readers of this
> discussion, as the temperament here may surprise you. Right or wrong
> staements or
> assumptions make a lot of difference in this case.
>
> Bj?rn S?rheim
>
Received on Sun 17 Feb 2013 05:29:29 AM PST