2012 DA14: How to Watch Tomorrow’s Record-Breaking Asteroid Flyby of Earth: Update Russia hit!

Posted: February 14, 2013 by Rog Tallbloke in solar system dynamics
Tags: , ,

Some great info from Wired Science about a fairly close pass tomorrow by 2012 DA 14

asteroid-660

Click for Animated GIF file. Source: Wired Science

A large space rock known as asteroid 2012 DA14 will be zipping by our planet on Feb. 15, coming within 28,000 km of Earth, the closest approach ever seen for an object its size. You can catch the event live using a backyard telescope or binoculars or watch it here on Wired with a collection of live feeds from around the world.

UPDATE 15-2-13 – 9.00am: Russian towns in the Urals have been hit by meteorite debris. Over 500 injuries so far reported. More here:
http://rt.com/news/russia-meteor-meteorite-asteroid-chelyabinsk-291/

Asteroid 2012 DA14 has a diameter roughly equal to an Olympic-size swimming pool, 50 meters, and an estimated mass similar to the object that caused the 1908 Tunguska Event that destroyed a large swath of remote land in Russia. Thankfully, there is no chance that the asteroid will impact the Earth. It will come within 27,700 km at its closest approach, less than a tenth of the distance between the Earth and moon.

DA14 will also pass within the paths of geosynchronous satellites, which orbit at about 35,800 km

Comments
  1. kim2ooo says:

    Reblogged this on Climate Ponderings and commented:
    COOL!

  2. Scute says:

    Shame they couldn’t have had a little something ready on the side to scurry up there and take a look! I’m only half joking. This is Ariane’s back yard and NASA always knew there would be close flybys with little notice. It would also be good practice for if and when another small one was actually on course. Small asteroids might be amenable to being blown up and so do less damage on atmospheric entry. That strategy is no good for big ones but we are getting to the point (next 10-20 years) where nearly all the bigger-than-swimming-pool ones are visible from afar and therefore amenable to the deflection method.

  3. jorge says:

    iis it possible to view this asteroid with the human eye from florida???

  4. tchannon says:

    According to the map on the Wired site, no. Far East, Oz, etc.

  5. tallbloke says:

    Russia has been hit by a meteorite storm!

    Camera date stamp is older but watch the vid.

    9:07 GMT: “The object could be about a meter in diameter and weigh a few tons,” said Valeriy Shuvalov of the Institute of Geosphere Dynamics. “As it entered the atmosphere, it broke into a cloud of pieces that flew on, creating a blast wave and emitting light. That’s where the flashes came from, as well as broken windows. Most of the object’s material evaporated, the remaining pieces slowed down and fell. It was most likely of iron nature as it penetrated so far through the atmosphere. However, we still don’t have the exact data on the debris.”
    8:56 GMT: The Chelyabinsk regional governor reported that an emergency team discovered that a meteorite fell into a lake near the town of Chebarkul.
    8:49 GMT: The number of people requesting medical assistance has risen to 500.

  6. Article says :

    “Asteroid 2012 DA14 has a diameter roughly equal to an Olympic-size swimming pool, 50 meters, and an estimated mass similar to the object that caused the 1908 Tunguska Event that destroyed a large swath of remote land in Russia.”

    http://tallbloke.wordpress.com/2011/12/02/michele-casati-volcanicity-earthquake-geomagnetism-and-the-heliosphere/comment-page-1/#comment-10225

    http://tallbloke.wordpress.com/2011/12/02/michele-casati-volcanicity-earthquake-geomagnetism-and-the-heliosphere/comment-page-1/#comment-10270

    meteorite not ….

    change atmospheric circulation
    generate geomagnetic storm
    generate St. Elmo’s fire

  7. Tim Cullen says:

    Meteorite hits Russian Urals: Fireball explosion wreaks havoc, up to 500 injured
    Russia’s Urals region has been rocked by a meteorite explosion in the stratosphere. The impact wave damaged several buildings, and blew out thousands of windows amid frigid winter weather. Hundreds are seeking medical attention for minor injuries.

    According to unconfirmed reports, the meteorite was intercepted by an air defense unit at the Urzhumka settlement near Chelyabinsk. A missile salvo blew the meteorite to pieces at an altitude of 20 kilometers, local newspaper Znak reports quoting a source in the military.

    http://rt.com/news/meteorite-crash-urals-chelyabinsk-283/

  8. @ TB

    What is “fireballs” ?
    coincidence ?

    http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usc000f76f.php
    Magnitude 6.6 – NORTHEASTERN SAKHA, RUSSIA
    2013 February 14 13:13:53 UTC

  9. Richard says:

    Hmm. Given that the approach direction of the Asteroid is from the South Pole (in the NASA animation the South Pole is central on Earth for most of the approach) and the meteor was in the Urals (i.e. the Northern hemisphere) I cannot see how the two are directly related.

    Mighty sharp turn otherwise!

  10. Richard says:

    Michele Casati says:
    February 15, 2013 at 9:41 am

    “Magnitude 6.6 – NORTHEASTERN SAKHA, RUSSIA
    2013 February 14 13:13:53 UTC”

    In fact this is one of a long series of quakes in this spot I think (and far from the Urals AFAIK).

    4.5 140km WSW of Druzhina, Russia 2013-02-15 12:39:54 67.735°N 142.205°E 10.0
    4.4 123km WSW of Druzhina, Russia 2013-02-15 06:23:02 67.771°N 142.618°E 13.8
    4.8 136km WSW of Druzhina, Russia 2013-02-14 20:26:15 67.621°N 142.485°E 10.0
    4.6 135km WSW of Druzhina, Russia 2013-02-14 17:17:42 67.655°N 142.451°E 15.9
    4.9 131km WSW of Druzhina, Russia 2013-02-14 15:14:56 67.614°N 142.623°E 16.5
    4.9 138km WSW of Druzhina, Russia 2013-02-14 15:08:35 67.572°N 142.513°E 16.9
    4.6 126km WSW of Druzhina, Russia 2013-02-14 13:44:29 67.867°N 142.436°E 10.0
    6.6 134km WSW of Druzhina, Russia 2013-02-14 13:13:53 67.580°N 142.593°E 10.1

  11. Richard says:

    From the Pravda link

    “The 45-meter-long asteroid weighing 130,000 tons, which will approach the Earth tonight, February 15th, is surrounded with a “cloud” of rocky rubble. One of them fell this morning near Chelyabinsk. Several other meteorites fell on Friday afternoon in Kazakhstan. Many Russians say that today’s events remind them of the film “Armageddon.”

    Given the approach path of the Asteroid I cannot see how this metor can be part of the “cloud” of anything following or preceeding that object.

    No doubt someone with more orbital knowledge will be able to say definitifly if that is the case or not. I do not always expect journalists to get the science right and the North/South question is still there.

  12. Gray says:

    Interesting write up and chart showing track of asteroid.

    http://www.bbc.co.uk/news/science-environment-21442863

  13. tallbloke says:

    Other sources say it is not connected

  14. vukcevic says:

    I don’t think he likes being photographed (nuclear powered ‘meteor’?).
    Any expert comments on what is the instrument, protective white suit?
    http://www.vukcevic.talktalk.net/RusMet.htm
    taken from crater impact image
    http://content.izvestia.ru/media/3/news/2013/02/545032/DSC00622.JPG

  15. tallbloke says:

    The car is going round a bend, so the angle of the light from the meteor hitting the smears on the windscreen is changing. I think the light flashes are a combination of this and a camera lens flare issue. The trajectory of the light flashing puts it as the last two points of a hexagon. camera lenses often have 6 blades in the aperture mechanism.

  16. tchannon says:

    vuk,
    Probably a Geiger counter tube. Perfectly reasonable given no-one actually knew what had happened.
    Tube has to get close to read beta.

    Quick find, now put the head on a hockey stick
    Image wikipeida

  17. oldbrew says:

    A leading Russian MP is pointing the finger at the Americans.

    http://metro.co.uk/2013/02/16/meteor-was-new-us-weapons-test-claims-russian-mp-3480678/

  18. Scute says:

    I think the idea of the Russian meteor being related to 2012DA14 should be resurrected. I say resurrected because the idea was so roundly slapped down by NASA within hours of the impact and never discussed again. Most of the information below was gleaned from NASA’s own JPL Horizons ephemeris for 2012DA14.

    Let me begin by addressing a few myths that seemed to sew it up regarding the lack of any link between the two

    Firstly, the direction of approach was not on the night side of the earth but on the day side (2012DA14 flipped under and up round the back only in the last 5 hours) and the radiant was not, as variously described, “the South Pole” or -81 degrees (implied by the above as being -81 to the night side), but at -69 degrees on the sunward side.

    Secondly, the radiant had a right ascension of almost exactly 00 hours ,that is, 30 degrees east of the sun (which was at 21 hours 54 min of RA on the day) in the equatorial plane. The Russian (Chebarkul) meteor came in at 13 degrees east of the sun in local horizontal coordinates.

    Thirdly, the incoming trajectory of the meteor was not north-south but on an azimuth of 99 degrees i.e. 9 degrees south of east. Since it was sunrise this meant that the meteor came from a direction close to the sun (13 degrees east of it), in other words, coming in over a great circle running down the globe to the south, although a better approximation would be south east, This was possible because the Earth’s axis was tilted back by 12.5 on that date, making a late sunrise for Chebarkul, so watching the sunrise on a somewhat tighter, northern latitude line meant looking along a straight line that soon scribed south eastwards in lower latitudes (rather than curving round the 55 degree North line).

    Fourthly, 2012DA14 was not going “too slow” for a related fragment to arrive at 17km/second: its radiant, relative velocity to the Earth before being accelerated was 12600mph. That is 5.6 km/ sec. If you add to that the freefall velocity of 11.2 km/sec (the corollary of escape velocity) you get 16.8 km/sec. Add to that the eastward rotation of the earth at 55degrees north at an Azimuth of 9 degrees south of east (0.2 km/sec) you arrive at precisely 17km/sec. This is the same calculation that Zuluaga and Ferrin (and now, NASA) must have done in reverse for their version of the reconstruction of the trajectory: I calculated the radial speed of their hypothesised orbits at the Earth’s position (r value/ radius from sun=1AU) on the day of impact (but without the Earth’s gravitational influence added) and ended up with 34.8 and 35.2 km/sec for the 2 posited orbits. That amounts to 5 and 5.4 km/sec relative to the Earth, respectively. Adding the freefall velocity and the eastward rotation you get 16.4 and 16.8km/sec. The difference between these posited orbits and the posited 2012DA14 fragment is that they invoke the head-on trajectory solution with little or no curvature as they are pulled into the gravity well. If it’s a bulls-eye hit the curvature is zero. The Zuluaga and Ferrin video shows the meteor coming in from about 3 degrees above the solar plane. The NASA video now shows the same.

    I believe there are multiple solutions between head on (3 degree inclination) and an 11.6 degree inclination (11.6 deg being the solar plane analogue to the -69 degree radiant from a geocentric view). These various solutions involve increasing degrees of curvature as the meteor is pulled into the Earth’s gravitational well but curvature in freefall doesn’t make the final velocity any slower. By the way, none of these high curvature scenarios would involve capture in orbit- it’s either impact or escape along a hyperbolic path back out of the well. And high curvature means a 50 degree ‘q angle’ (half way through the turn). It’s the q angle that determines how far round to the north the meteor can curve and still impact rather than miss and escape.

    The last myth is that at 55 degrees latitude Cherbarkul is too far North for any fragments to hit. This is not true because from a -69 degree radiant, the ‘equator line’, or tangent line, that 2012DA14 could see from below was shunted upward (from the real equator) on the sunward side by 21 degrees. Due to the vagaries of the trajectory of any purported fragment (see below), it would still require around 55 degrees of hyperbolic turn from that raised equator line onwards, although that describes a track all the way to Chebarkul- atmospheric entry would begin at 50 degrees round. For an idea of the sort of curvature needed for the fragment, I plotted a curve from first principles (subtracting the freefall component of velocity from the baseline, straight velocity of 17km/sec) and came up with a q angle of 50 degrees. For some perspective, the Apollo missions came in on a hyperbolic orbit at 11.2 km/sec and still got 69 degrees round the back of the globe, regardless of rotation and a sedate 1080 mile reentry. Even 2012DA14 curved 30 degrees or more for a q angle of 15 deg and that was under the influence of one tenth the gravity. 50 degrees is probably an upper limit but that is exactly what is required for a 2012DA14 fragment riding along on the radiant angle to turn in hyperbolically and hit Chebarkul at a low trajectory.

    One other point, though not classifiable as a myth is that 2012DA14 is being characterised by NASA as a CO or CV type chondrite (carbonaceous with calcium and aluminium inclusions) based on spectral observations whereas they say the Chebarkul meteor is a stony chondrite because the few pieces found so far “are reported to be silicate rich”. This, they say, rules out any link. This may be true but the whole tenor of their delivery is one of running scared and has to be looked at in the light of the following quotes, all within a minute on one video:

    [re 2012DA14] “there was no danger of a collisions, NASA assured people”

    “… In a one in a million chance that still has NASA scientists shaking their heads”.

    “These are rare events and it’s incredible to see them happen on the same day.”

    As things stand as of 5th March 2013 , I feel that the evidence presented here is more convincing than some spectral measurements not chiming with a few reported silicate bearing fragments.

    So we now have a completely different, sunward radiant of -69 degrees of declination. In fact, for a fragment travelling 50,000 miles sunward from the track line of 2012DA14 and 16 hours ahead, it would probably come in from nearer to a -66 to -67 degree trajectory before being really hiked round on its hyperbolic orbit (its close encounter-to-impact trajectory). 2012DA14 itself turned in by 2-3 degrees from its side of the track in the last day before starting its 30 degree hyperbolic turn. A -66 or -67 incoming trajectory for the hypothetical fragment means the raised ‘equator line’ was up to 24 degrees higher on the sunward side, reducing the required curvature even further, possibly to 47 degrees before atmospheric entry. Indeed, that sunward fragment track, displaced as it is seemingly arbitrarily, at 50,000 miles over and parallel to 2012DA14 actually allows for 10-12,000 miles or 2 degrees of inward curvature from 03:00 on 14th February, 24 hours up range. This is before being really hiked in from a -66 to -67 degree point at about 22:00 UTC on February 14th, some 5 hours from impact.

    You can download the ephemeris for 2012DA14 from JPL horizons website (click ‘web interface’ and enter ‘observer’ ‘geocentric’ and dates from 1st Feb 2013 to 28th Feb 2013 at hourly intervals). I suggest the entire month so as to give a better feel of what’s going on. It’s easy to scroll up and down quickly. It doesn’t show speeds but I got the figure of 12600 mph from a news item and checked it against the orbital speed and inclination of 2012DA14 for the vertical component, then derived the horizontal geocentric component from that. Those vectors do pretty well add up to a 12600mph, 69 degree slope until one or two days out (300k to 600k miles). The JPL video has 2012DA14 at about 13,500 mph at 4 hours out. I apologise for the lack of links, they are currently playing havoc with my formatting. I might do another separate comment with some links.

    I have described the trajectory of the hypothetical fragment. Now I need to describe where to look for it in a forensic sense- using astrodynamics software to rerun different scenarios with the meteor exiting from a narrow window around the proposed path. If anyone here has astrodynamics software, please feel free to join in and prove it one way or the other. I have no software so feedback would be welcome.

    The best place to look for the fragment is emerging from a window bounded by a geocentric declination of between -59 and -65 degrees and a right ascension of between 22H and 2H 30 minutes. The declination angles of the window aperture are less than the radiant and trajectory angle because the fragment is now cutting up through the angle lines, past the radiant, trying to get level with the earth in the same way that 2012DA14 cut the other way through the angles to come up the back: the radiant becomes irrelevant at this point and that’s why it was totally misleading to talk about a -81 degree radiant.

    Also, because the fragment is cutting up through the declination angles, its own trajectory angle cannot be described with declination angles any more- except for a bulls eye geocentric hit. It has to be aiming over the top of the Earth to get a chance of being pulled in hyperbolically over the ‘new’ equator line for a hit. This means that whatever declination angle is chosen for the instantaneous position of the emergence of the fragment through the window, its actual trajectory angle would need to be greater by 3 to 6 degrees or so in order to aim it away from the geocentre to two or three thousand miles out from the equator line, that is, two or three thousand miles from the disc it sees above it and with the same right ascension as the RA of the fragment emerging at the window. This angle cannot be geocentric because it has to look as if it will miss the Earth. Looked at another way, it is a line running parallel to a declination angle that starts 3 to 6 degrees in from the fragment emergence point, measured radially inward. This jiggling of inputs for the fragments own inclination is nevertheless bounded by the upper limit of 69 deg, the true radiant angle. There is also potentially a small amount of leftward (solar plane y axis) component as they emerge round towards the 2H 30 mark because these are trying to pass by the side of the Earth but get caught. I think these, around the 0 to 1H mark (0 to 30 degrees of right ascension) are the best candidates.

    That arrival window describes a curved slit sitting somewhere roughly below where the southern tip of New Zealand was at the time of impact. The fragment would be emerging at a trajectory angle of between -65 and -69 degrees of declination (that is, its own path angle as opposed to the box perimeter angles). This needs to be set at 10 hours 20 mins (clock time) up range (about 150k to 170k miles?) so that the fragment would be coming through it at 17:00 UTC on February 14th 2013. Some time not long after that the trajectory angle would start to curve in noticeably on its hyperbolic path.

    I extended the window round to 2H 30M because of the angle discrepancy between the radiant and the final trajectory. This was up to 17 degrees when playing with equatorial-to-horizontal coords for Chebarkul (but one-way calcs made this inexact) and only 8.5 degrees using old fashioned cotton stuck to a globe.

    Incidentally, using the globe method resulted in a view, looking downrange along the trajectory, identical to the several Youtube videos of 2012DA14 when freeze-framed at 3:20 UTC on 15th February. It was the view from DA14 as the Chebarkul meteor hit- you can see the beginning of the meteor’s ground track over Taiwan before it disappears over the ‘equator line’ at 22 deg north. You can see that its hyperbolic trajectory extends round and down past and almost parallel to you to your right, in other words, the same trajectory but displaced 50k miles to the right. This ‘almost parallel’ track would correspond to the sunward track of the fragment not being quite sunward but with a slight right ascension from that track of a few thousand miles so that the fragment came from further round towards 2H 30 but up and in on the correct line. This allows for the 8.5 degree disparity.

    It should be said here that 2012DA14 seems to have corkscrewed itself by between 5 and 12.5 degrees depending on where you make the cutoff between true radiant and local approach. It is apparent in the ephemeris (you can’t see its subtlety in any video or diagram). It may seem to defy physics (not orbiting on a great circle) but I would ascribe it to the slowing down 2012DA14 as its orbit goes from inside track to outside track and its relative prograde motion with respect to the Earth went nearly to zero. It was almost stationary in the prograde vector, sitting at -86 declination and ready to be plucked up along the most convenient longitude line. Because there was some forward motion still, it did get plucked up pretty well opposite but not 180 degrees- the entire pass was 4 or 5 degrees inside one hemisphere, resulting in a 5 to 12.5 degree twist. If this happened to the proposed Chebarkul fragment, it would have skewed in exactly the necessary way to bring it round to this new ‘wrong’ 8.5 degree-off trajectory and heading over Taiwan, China, and into Chebarkul. This is why the search box extends round to 2H 30M. It’s because the fragment oversteps ever so slightly before skewing. For that reason, once you get round to 00H to 2H, the trajectory emerging from the box will have a sideways component to the left (positive RA) ie not radially inward. These candidates will be skewing 8-10 degrees anticlockwise as you look down on them as they rise and will probably do so over the last 80,000 miles. This is how their local ‘radiant’ is skewed round. That’s if DA14 is anything to go by.

    The fragment would be travelling at about 13,000 mph through the window but it would be best to plug into the software ephemeris details for 2012DA14 for the speeds from far out so as not to start at an arbitrarily high speed. However, beware of piggy-backing on 2012DA14 data to extrapolate hypothesised fragment data. I have seen, among other things, a rather amusing graph that relied on like-for-like parallel trajectories with earth skimming fragments refusing to bend round under the influence of 10 x the acceleration 2012DA14 was experiencing. That is their ‘proof’ that the fragments can’t make it north of the equator. That was on a respected astronomy blog.

    If all goes to plan, you should see all manner of near misses, flying over Asia and Russia, a few direct hits on the Southern Hemisphere in a wide band from New Zealand northwards and a few Northern Hemisphere hits, one of them right on Chebarkul. You’ll have to play with it though, maybe venture a little way outside the window if needs be. The worst that can happen is some very interesting near misses- but I really do think there will be hits. This need for playing around is reflected in the fact that some solutions could imply the need to add 5 or 10,000 miles to the track line displacement further uprange (back down the slope) for a possible 60,000mile or so displacement. You can’t use the 2012DA14 trajectory, displaced and pasted to the other track- it’s bending the wrong way from 24 hours out. Even a mirror image wouldn’t be faithful due to its greater radial displacement.

    THE POSITION OF THE FRAGMENT IN ORBIT- THE BIGGER PICTURE:

    I will acknowledge that when NASA said that the Chebarkul meteor was not following along the same path as 2012DA14 they were right but only in a highly technical sense. Any fragment passing within a radius of a few thousand miles of the trajectory would not have impacted the other side of the Earth. But when considering the possibility meteor showers, you have to think in terms of millions of miles, even for asteroidal showers such as the Geminids and the Quarantids, because the Earth takes days to travel through them. I think NASA was clutching at straws. You have to look at the bigger picture and besides, the proposition as put forward in this comment isn’t played out on a vast scale in solar system terms.

    I propose a fragment riding just 200,000 miles above 2012DA14 (north with respect to the solar plane). Just stating that baldly might understandably invite querying as to why they should be related. However, visualising it scaled down, it would be the equivalent of two tiny pieces of rock on an orbit 54 metres round, mirroring each other’s every move in speed, inclination and eccentricity, all the while staying exactly 2 centimetres apart, one directly above the other. I would consider those two pieces as related, one broken off from the other.

    When the 65,000 mph prograde element of the Earth’s orbit is removed we get the geocentric element of relative movement between 2012DA14 (along with its hypothetical fragment) and Earth. Gone is the gentle 10 degree inclination with respect to the Earth’s orbit, with the asteroid climbing gently up a slope and sedately past the night side. It’s turned into a precipitous 69 degree climb, skewing round to vertical as 2012DA14 was apparently dragged up from under the South Pole and slung shot vertically above. That does serve a purpose for geocentric calculations and visualisations but it is as well to remember that it helps to plug mentally into the elongated, gentle slope version from time to time so as to get a good feel for what is really happening to the Asteroid and the purported fragment as they pass Earth.

    Once the frame of reference snaps to geocentric you see the fragment rising up ahead of 2012DA14 and slightly to one side and they start to look a little disjointed. But when you snap back to solar system view with them both sailing along, rising up alongside Earth, you see that one is directly above the other: the 50,000 mile displacement is really just a 200,000 mile vertical displacement which, when looking down the -69 degree radiant makes them appear to be 50,000 miles apart. That said, there may be a fraction of further displacement to the outside of the orbit track too to allow for the skewing effect. They only ride on different tracks because of their vertical displacement and those two tracks went either side of the Earth. One was too close and the fragment hit (hypothetically). There’s something telling about that vertical nature of the relationship: the proposed fragment is following the exact same track but directly above. If it had been shifted a few thousand miles long ago, perhaps by a small collision, then previous close encounters, passing beneath the Earth would have widened that gap quite dramatically: 0.01mm/sec^2 differentials in gravitational acceleration add up to 4m/sec over a four day encounter within a million miles. That’s tens of thousands of miles per year. 200,000 miles isn’t as far as it seems.

    I doubt if its possible but old sky scans might show up the culprit: at 12 million miles it would be 15 minutes of arc displaced from 2012DA14 when looking straight down the 69 degree track and would be offset at around the ’9 o’clock’ mark. For the 2012 pass at 6 million miles it would have been around one degree offset above at about the 12 o’clock mark.

    Happy hunting!

    Scute

  19. wayne says:

    Scute, very nice comment!

    If I read you right, if you were standing on the ground underneath it facing the direction it was tracking you would be facing 9° north of east, 81°? My first inclination was that may have been maybe a displaced leading trojan. Don’t know if 2012DE14′s gravity is enough to hold something in that manner, just a first gut reaction. The chances those not even being related in any manner is something like a zillion to one. ;) And of course Earth’s orbit velocity, rotational velocity and attraction has much to do with its orientation just before impact. Nice investigation.

    Have you any information as to its slope to the surface tangent plane, how steeply it was sloped vertically? At first glance it looked more like a skim nearly parallel to the surface but a video can be deceptive when you don’t even know which direction the camera was even facing.

  20. Scute says:

    Hi Wayne

    It’s actually the south side of east that it’s coming in so it’s 9 degrees south of east (and maybe 10 or so- they are still nailing it down). So it’s 90 degrees (azimuth from north swivelling clockwise to face exactly east) – and then plus the 9 for a 99deg azimuth facing east southeast (9 deg south of east).

    As for the idea of any gravitational link between the two rocks, it would be zilch but a broken off fragment would glide along in the same orbit, a few thousand miles away for years simply because it came from the parent asteroid. That said, it could get whipped further away by close passes to Earth due to differential gravitational accelerations but it would have to be a good way away in the first place, 10k miles plus and my brief mention of that was based on general playing around with differential accelerations between two pieces 100,000 kilometres apart already (metric so I can do the calc) and positioned together between 1 million and 2.6 million km away for a 3 or 4 day pass. At less than 10,000km separation I reckon it would take aeons to be pulled out from close proximity. But hey, they’ve been around for aeons so that’s possible!

    2012DA14′s escape velocity is about 2cm per second squared so you are out of its influence when still very close by. But there’s no coincidence in their shadowing each others every move in terms of the general orbital parameters, even as they get nudged this way and that- until a big nudge comes. If the posited fragment had just missed, it would be on a completely different path from DA14 now.

    As for the inclination of the trajectory, the link below is to a blog which had a crowd sourced video-and-google-earth fest to nail down the trajectory. I thought the post should be cited for an award for internet cooperation or something similar. Returning there to get this link I see it’s gone global and people are talking about commending it.

    The link is to the story about the popularity and the actual post about the trajectory is linked in the first line.

    http://ogleearth.com/2013/03/chelyabinsk-meteoroid-comparing-paths-with-the-pros-in-google-earth/

  21. wayne says:

    Look Scute: http://neo.jpl.nasa.gov/news/fireball_130301.html
    http://neo.jpl.nasa.gov/images/Chelya_track_annotated_s.jpg

    I see what you were saying, facing it, you would be facing slightly south of east. NASA shows your track that here ~9° north of west having crossed over Mongolia and that even gives the height as it was inbound. Neat info. :) Finally have got a better mental picture of just what occurred. Wish they would have overlaid the 2012DA14 orbit on some those later estimated orbit graphics.

    Sometimes 2012DA14 was described as being south to north, more like parallel to a polar orbit, but now I understand it was basically ecliptic with a small inclination, much like that orbit of the meteor shown. Thanks for bringing some clarification.

  22. tallbloke says:

    I think a diverging trajectory may have evolved as the objects came in through the solar system. Wal Thornhill has an article up about the asteroid the NASA probe fired a projectile at. He predicted they’d get a much bigger crater than they predicted, because of the differential in the charge. He was right. So if the Asteroid and meteor were picking up charge as they ploughed into the solar wind, it may be possible they started to repel each other.

  23. wayne says:

    Ah, very true tallbloke. Now that is a place I can see charge having a possible large influence… on small and near objects without ionospheres that can shed imbalances.

  24. vukcevic says:

    If meteor was part of, or captured by the asteroid’s gravity many thousands of years ago it would be spiralling around the asteroid’s path, possibly at some distance which may be few thousand km. On approach to the Earth, once meter found itself on the Earth’s side of the asteroid (gravity force inversely proportional to the distance square) it would be under greater pull than the asteroid itself, peeling away fom the asteroid’s trajectory, under overwhelming Earth’s gravity moves onto a new collision path totally unrelated to (by then) the fly-by asteroid.

  25. tallbloke says:

    Guys, we should be conversing on Andy Cooper’s debut guest post rather than here. Can we move across please.

  26. Scute says:

    OMG, it’s like global warming spin all over again! Thanks for the link Wayne- I was on that page only a few hours ago and they’ve added the diagram at the bottom since then. What they’ve done is show their version of the meteor streaking majestically along the solar plane with its 3 degree incline and compared that to the geocentric path for 2012DA14 , looking as if it’s clambering up a rope ladder! This version strips out the prograde orbital vector of (ahem), 65,000 miles per hour and only concentrates on the vertical component of 2012DA14′s approach (13000-17450 mph). In reality, DA14 should be streaking across the top of the picture with a gentle 11.6 degree upward slope!

    Even the downward slope of their meteor is slightly questionable: Zualaga and Ferrin also showed a downward 3 deg slope i.e. the correct sort of trajectory for a direct hit, but quoted the line of ascending node as being 326 degrees. 326 degrees was the position of the Earth that day and the ascending node really does mean it’s the node where the orbiting body ascends above the plane of the solar system. The inclination is measured in the little triangle formed just beyond the crossing and if it’s positive it means that’s what you note down as the as inclination. And if it’s a positive value then it is a positive, rising slope- just like 2012DA14. This would put their trajectory riding slowly up towards the solar plane at 3 degrees along with 2012DA14 converging from below at only 8.6 degrees (11.6deg inclination). As it is, they should be shown converging at 14.6 degrees at most.

    If their version was compared as geocentric, like for like with DA14 it would be showing only the vertical and sideways component and would be a steep slope upwards (or downwards if my suspicions above are confirmed). Not as steep but still very noticeable.

    And it gets worse: they show their trajectory at a constant speed of 35,000 mph (which I extrapolated from the known geocentric approach speed of DA14 and measuring its hour ticks in the diagram). This is basically the impact speed extrapolated out into space with no speeding up in the gravity well, no nuances of relative speed of orbits of meteor and the earth (5.4 km/sec; 12000mph) further out, before speeding up). And if it’s heliocentric, as the depicted inclination shows, it should be 35km/sec. And the 35,000 mph they show is nearer to 15.7km/sec anyway, not the 17km/sec commonly stated or the 18.6km/sec cited on this very same page. It’s quite appalling; in fact, I give up trying to explain exactly what they are trying to say. But what is certain is that it is wrong to the point of…ho-hum, haven’t I heard this before… being disingenuous.

    I have to say, I think it’s quite astounding they have the gall to do this.

  27. Scute says:

    Whoops, I just saw your comment , Rog after posting mine without checking what was happening down below. Point taken.

  28. wayne says:

    Ditto, didn’t realize Andy Cooper had a debut guest post up. Moving.