Reconstructing the Chelyabinsk meteor’s path, with Google Earth, YouTube and high-school math

[March 2: Read the follow-up article, Comparing paths with the pros in Google Earth]

[March 9: Read the follow-up article, Three trajectory models of the Chelyabinsk meteoroid compared]

[April 5: Help scientists to more accurately calculate the trajectory. Visit www.russianmeteor2013.org to contribute videos or help with the analysis.]

Like many others, I was absolutely astounded by the meteor strike over Chelyabinsk when I woke on Friday morning. One silver lining to our self-surveilling society is that an event of this magnitude is certain to get caught on the myriad of always-on dash- and webcams. I for one could not get enough of the videos.

Might it be possible to use this viral footage with Google Earth to have an initial go at mapping the meteorite’s trajectory? I was pondering this question some 2,500km away from Chelyabinsk when I chanced upon this video:

That place is easy to find — it’s Revolution Square at the absolute center of Chelyabinsk, looking almost directly south. It is also easy to measure — the distance between the two central light poles is 32 meters, as per a quick measurement in Google Earth, while the five lanes of traffic going right to left (west to east) measure 19 meters. From this it is easy to estimate the height of the light poles to be around 12 meters — an estimate corroborated by numerous panoramas in Google Earth showing people next to these lamp posts, giving us added data points.

Using all this information, I was able to do some image analysis in Photoshop on the lengths and angles of the shadows as the meteor streaked across the sky. Here’s an animated gif showing the result of that:

gif-animation-small

The ensuing grade-school mathematics (SOHCAHTOA!) resulted in three lines of sight at three instants a few seconds apart. (For the sake of the record, I roughly calculated them to be towards 122 degrees at an inclination of 33 degrees at 9:20:28.7, towards 187 degrees at an inclination of 40 degrees at 9:20:32.2, and towards 222 degrees at an inclination of 32 degrees at 9:20:33.4. These times are the video’s own timeline, though they appear to correlate closely with the timelines of other videos.)

This allowed me to draw an inclined plane in Google Earth that should include the meteor’s path, though it does not allow me to know the distance of the meteor from central Chelyabinsk, nor its speed.

meteorgeview

However, we have more clues. We know a fragment of the meteor landed in Lake Chebarkul, roughly 70km WSW of Chelyabinsk. Gratifyingly, the inclined plane generated from the above video intersects with the crash site. Also useful was the estimate by the Russian Academy of Sciences that the meteorite hit the Earth’s atmosphere at around 50,000 km/h, shattering at an altitude of 30-50km. If that was the rough speed of the meteor as it burned up in the video, then the 4.7 seconds between the first and last shadow measurements would have seen it travel 65 km. Fitting a 65km line between these two lines of sight allows us to draw a straight line path for the meteor towards the crash site, with the first measured time yielding a height of 29km, which is the moment the meteor first brightened enough to give a clear shadow.

Download the visualizations for this as a KMZ file to open in Google Earth. Do play with the opacity slider of the overlay to check the alignments yourself — it’s most of the fun.

Screen Shot 2013-02-16 at 16 Feb 02.07.21 CET

How does this data square with the Meteosat 9 image that has being doing the rounds? At first glance, not well: Overlaying the image in Google Earth and aligning the border with Kazakhstan shows a 240km contrail that appears to end some 75km to the ENE of Chelyabinsk, even though the path when traced on the ground also leads directly to Lake Chebarkul.

At first, I thought the image might have been taken 5 minutes earlier, before the meteor streaked straight across Chelyabinsk proper, because the image’s metadata gives us a time of 3:15:00Z, or UTC, which is 6 hours behind Chelyabinsk time. But no meteor is going to take 5 minutes to traverse 75km, so we’ll just have to live with the time discrepancy. Webcams are not atomic clocks.

Much more interesting is the fact that if you look at the position of Meteosat 9, which is in a geostationary orbit, you see that Chelyabinsk is near the horizon of its view of Earth. This leads to extreme foreshortening in the snapshot of the meteor’s contrail:

Meteor vapour trail, 15th Feb 2013
(Notice the outline of the Sea of Azov in the foreground. Here is another version showing the thermal impact (source).)

The version used in the overlay is an enhanced view of this image, taken from the same angle. (The blacked-out upper right-hand corner of the overlay is behind the horizon as seen from Meteosat 9.). If you simulate this view of Chelyabinsk in Google Earth, you see that in fact, the contrail aligns quite nicely over Chelyabinsk considering that it would be 30km high and at such an extreme angle over the horizon. So the 4.7 seconds of maximal brightness (with contrail) do get to happen just south of Chelyabinsk proper, as per the above video, and without contradiction by Meteosat 9.

I feel this post would not be complete without some big caveats: I am not a trained scientist; I don’t know if meteors travel through the atmosphere in straight lines or at constant speeds (I assume they don’t, but that it doesn’t matter for back-of-the-envelope type calculations). Still, it is satisfying to know that with judicious use of Google Earth, YouTube and Photoshop you can get quite far in the meteor simulation game. I can’t wait to see what the professionals come up with.

UPDATE 2013-02-16: Via SebastienP in the comments comes another triangulation, comparing the calculated path from the KMZ file with the view from another dash cam. It holds up pretty well!

stefangeensreconstituti

(Source)

UPDATE 2013-02-17: In this comment, some smart calculations by Sean Mac are confirmed by a video he’s found showing the contrail crossing almost exactly above the southern suburb of Yemanzhelinsk. I found the exact vantage point of the video he references in Google Earth by connecting this Panoramio photo to this view in the video.

This suggests the meteor’s trajectory towards Earth was higher and steeper along the inclined plane of sight derived from the central Chelyabinsk vantage point than the initial calculation suggested. That’s not surprising, as that calculation was based on an initial estimate of the velocity by the Russian Academy of Sciences, which now appears to have been on the low side.

I’ve now added a second path for the meteor in Google Earth, together with the location of the vantage point in Yemanzhelinsk, in this KMZ file. Open it as a complement to the first KMZ file to see what I would consider to be an upper bound (green) for the trajectory along the same inclined plane, with a new likeliest path (red).

latestredline

“Looking up” in Google Earth from the vantage point in Yemanzhelinsk (I can because I have a 3D mouse from 3DConnexion), I get a very similar angle of view of the contrail when framed by the NNW axis of the buildings on that square.

abovehead

A further video showing the perspective from the town of Korkino further north (included in the new KMZ file) shows that the meteor passed a little to the south of there, allowing for a pretty accurate triangulation. (Thanks to Robin Whittle and liilliil in the comments for the heads up.)

UPDATE 2013-02-22: OK, so this is kind of special: An astrophysics paper has just been submitted to ArXiv.org that models the orbit of the Chelyabinsk meteor, referencing this blog post as a starting point: A preliminary reconstruction of the orbit of the Chelyabinsk Meteoroid by Jorge I. Zuluagaa and Ignacio Ferrin. Details are here, and here comes the resulting animation:

[March 2: Read the follow-up article, Comparing paths with the pros in Google Earth]

[March 9: Read the follow-up article, Three trajectory models of the Chelyabinsk meteoroid compared]

[April 5: Help scientists to more accurately calculate the trajectory. Visit www.russianmeteor2013.org to contribute videos or help with the analysis.]

374 thoughts on “Reconstructing the Chelyabinsk meteor’s path, with Google Earth, YouTube and high-school math”

  1. Meteors travel through the atmosphere like any other thing entering or reentering the atmosphere, on a parabolic arc. Ignoring the air, it’d be simply ballistics, but the air slows the object in a non-linear manner, due to increasing density of the atmosphere as it comes down and slows down.
    But, as you said, for a quick back of the envelope calculation, it’s quite close enough for government work. ;)

    You also made one assumption, that the impact site was the path of the meteor. Not exactly, one fragment landed there, others may have traveled less or further, they’re fragments as it disintegrated and made rude noises that blew window frames in, broke glass, collapsed one factory roof and pushed in part of that factory’s wall.

    Here’s one to bake your noodle. A few minute either way, earlier or later in our mutual orbits, it’d have been a fireball that went back into space again or a city crushing repeat of the Tunguska event- over a populate area.

    BTW, good job watching the shadows. Not many do that simple trick to establish path.

    Here’s another rough estimate, around 1.0 to 1.2 psi overpressure was experienced in the city that suffered damage, I’m thinking on the high side, as window frames were blown in and not only did a factory roof collapse, but part of the wall near the roof was pushed in.
    That’s a LOT of energy being put out at 30-50km up!

    1. wzrd1 on February 16, 2013 at 03:44 said:
      “Meteors travel through the atmosphere like any other thing entering or reentering the atmosphere, on a parabolic arc.”

      Since a large meteor would be only slightly slowed by the air, it would follow a HYPERBOLIC arc.

      1. Not really sure on that one, though air braking is variable, depending on altitude/density, gravity is still curving its path.

      2. If you ignore air resistance, _and_ assume the earth is flat and gravity constant (doesn’t decrease with height), then the path is parabolic. If you assume a round earth with gravity pointing towards the center and decreasing with square of distance from center, then it’s either elliptical or parabolic, depending on whether total energy (kinetic+potential) is negative or positive.

    2. Sometime after 10PM EST, Feb 14, Philadelphia, PA, my Mother who is 91 and hard of hearing, came in from outside and asked me what all the noise was? She asked me if I dropped something big. I hear everything in our neighborhood, but I didn’t hear anything (I didn’t feel anything either.)

      Is it possible, she felt a sonic boom from the Chelyabinsk meteoroid?

      1. I’m just south of Philadelphia International Airport, no noise here, other than the usual noise from I-95 and the airport itself.

        1. Just got this Twitter from @tracesofjupiter; She wrote:Yes, because I, too, heard a boom here in Nebraska around 9:20PM CST

          I had tv on and screen door was slamming so I didn’t notice anything and I didn’t put it together until the next day but maybe the time zone difference proves it all wrong anyway.

          Thank you for response.

        1. I’m super doubtful. I’m one of those guys who could tell that a helicopter was inbound 5 minutes before it arrived.
          Couldn’t hear it, but I felt it coming from many miles away.
          Didn’t hear or feel anything out of the usual here.
          Now that I’m retired, it’s annoying. I feel news helicopters heading up or down the I-95 corridor and helicopters from the Boeing plant two miles away.

    3. Great job on triangulating the path! ( Have you looked at the Zapruder film? ;)
      On another forum, I was involved in a discussion of the energy release, as compared to an explosion. My guess is it was nearly a megaton, based just on a >2 psi shock front.

      Blast effects have been extensively studied ( our tax dollars at work ). See, for instance

      http://www.fourmilab.ch/etexts/www/effects/eonw_3.pdf

      Focussing and local merging of shock waves leads to localized effect, which complicates the “yield” estimates – there is talk of longer range effects resulting from high altitude air bursts and passing the shock through the jet stream. (p.94)

    4. The damage of zinc plant and opposite window across the street in dye-fab looks like affected by “ray of death”.
      Never clouse up around have no destructions or window breakings.

      1. The meteor came in at velocities that are hypersonic. It was still supersonic during the video. That places the sonic boom behind the fireball and meteor and the shock front of the meteor from super compressed air, plus turbulence and massive deceleration while entering the denser stratosphere to cause unimaginable stresses on the meteor.
        Those stresses finally reached the point that overcame the molecular forces holding the meteor together. Once it fractured in the largest release of energy and small particles flying into the plasma of the fireball and brightening it, the remainder of larger pieces would, already being overstressed as well, also fracture.
        Until, it was largely rubble, which would be much more easily slowed by air, lacking the incredible mass of the original full meteor and fall to the ground in a debris field many miles wide and long.
        At the altitude and angle, it probably was still moving at mach 20-25 when it finally reached the point that it lost integrity and began to disintegrate.

  2. After making the measurements on GE thanks to your model and the photomontage I made, I found out the Fire tunnel was roughly 1200m wide at an altitude of 17000m. o_O

    1. Based on the time difference (90s), the explosion is about 30.6 km away from the camera. Looking at the shadows, the meteor doesn’t explode directly above (almost).

      1. The sound was not an explosion, but a sonic boom, so it doesn’t necessarily connect with the brightest part of the path.

        1. Actually, it was an explosion. A simple sonic boom wouldn’t have traveled as far and as destructively.
          Overcoming the binding energy of the object requires significant energy and significant energy is hence released when it finally fractures. Smaller debris would then shoot outward into the plasma shock front created by its high velocity passage through every thicker air and flare brightly when entering that plasma sheath and vaporize smaller fragments. Larger fragments then create their own contrail and fireball and begin to fragment as well.
          Hence, the additional reports from smaller fragments also fragmenting until the fragments were small and light enough to be easily slowed by subsonic passage through the atmosphere to eventually fall to Earth.

          Take a large rock and keep hitting it with a sledgehammer. Now, think of that loud crack when the rock finally fails structurally. Scale that upward, add in reflection of the energy by the shock front of the leading edge of the fireball and reflection from the trailing sonic boom shock front, you end up with a directional reflector of variable geometry, depending on velocity and atmospheric density.

          1. Multiple “explosions” (rock collapsing under pressure) + multiple sonicboom/shockwave sounds looks to fit the pic/video I have seen.
            Interesting one pic below:
            http://www.flickr.com/x/t/0096009/photos/93249543@N04/8475399871/
            Shows fireball period in trail – but it remains basically within its own path – can see some expansion of the trail but still mostly in one direction – but it did not just explode in all directions like one might expect from say a bomb. So some combination of explosions/boom/shock would be my guess.

          2. Also thinking of the devices used to record the event most probably use “automatic recording level” (ie they adjust the recording level to the average of the surrounding sound) to get good sound without distortion. Which does the trick in most normal circumstances but does not react well to very sudden increases in sound. Typically the very first part of the loud noise will be distorted while the levels are adjusted. I think that might impact a little on these recordings of the sonicboom/explosions/shockwave too. That plus the rock(s) are moving and breaking up at 40x the speed of sound.

          3. Actually, it’s more than that, Gary. Consider small fragments flying out into the plasma sheaf that is surrounding the meteor.
            They’d rapidly vaporize, larger fragments shattering nearly instantly.
            Not true explosions in a classic sense, but not sonic booms precisely. It’s partially an instant vaporization, piercing the sonic boom shockwave, partially being reflected by it and ducted between the training sonic boom wave and the primary shock front caused by the intense air compression at the front of the fireball proper.
            There are quite a few things going on, all nearly instantly.
            So, in essence, you’re right, it’s a combination of explosions (vaporization events from entering the plasma sheaf), shock front at the front of the fireball from the meteor compressing the atmosphere and the trailing sonic boom. When the object finally drops below the velocity of sound, the sonic boom would have advanced, been close to the meteor itself, creating even greater stresses on it, then as it further slowed to subsonic, the sonic boom would disappear.
            Shortly after that, adiabatic heating of the air would quickly cease and only pressure from subsonic, but still high velocity flow of air would be effecting the remnants of the meteor, plus of course, gravity and eventually, it’d be at terminal velocity.
            Something still significant, considering the Hodges meteorite, which was grapefruit sized, crashing through a roof and ceiling, bouncing off of an old wooden radio, to strike a woman, bruising one side of her body. With such a great mass of 5.56kg.

  3. Cool work Stefan. All those different pictures and videos catching that fireball.. it’s nice living in the future, isn’t it?

  4. Nice work… I did a very similar analysis with time stamped footage from another traffic camera in Chelyabinsk. What was unique about the footage I used was that it was a video lasting ~6Mins… I was able to calculated the slope of shadows (much like you, using the 3,4,5 principle of right triangles). The First light of the video cast a shadow at the 46 second mark of the video at a slope of 1.4 the peak light intensity occurred 4 seconds later at a slope of 1.333 (which I assumed was the detonation point). 160 seconds later the shock wave hit the camera (i know this because the video captured a cars alarm going off).

    Knowns:

    Slope of peak light intensity (1.333)
    Shock wave to vantage point (160 Seconds)
    Speed of sound (1,126 ft/s)

    160×1,1126= 180,160/5,280= 34.12 (slope) Miles from vantage point to detonation point.

    34.12 miles / 1.333 = 25.6 Mile (Run) ground distance

    Using the 3,4,5 principal I could calculate that the height of the meteorite at explosion was ~20.5 Miles

    based on all that I could make this statement…

    The meteorite exploded 25.6 Miles SSW of Chelyabinsk at an altitude of 20.5 Miles. This would put the detonation point relative to the ground ~ 1.5 miles NE of of Yemanzhelinsk.

    To confirm I wasn’t way off on my calculations I searched youtube for “yemanzhelinsk meteor” and found this.

    Video confirms the epicenter was slightly NE of Yemanzhelinsk.

    Here’s an image of the video analysis that I used.

    https://dl.dropbox.com/u/472582/chelscreenshot.jpeg

    Just an FYI… you can calculate the speed of the meteor in your analysis by using the videos time stamp and the apex of the rises of your triangles.

    knowns:

    x= time stamp of triangle1
    y= time stamp of triangle 2
    z= distance between apex of triangle1 and triangle2

    velocity of meteor= z/(y-x)

    do the same with the time between triangle2 and triangle3 and you’ll be able to calculate the rate at witch the meteor was slowing down in the atmosphere…

    How did you plot your point on google earth???? That’s pretty cool.

    Nice to know i’m not the only nerd in the world!

    1. Nice work! Re calculating the speed from the distance in my example, that would be a bit circular in that I was only able to come up with a distance based on a given speed (from news reports). Should the speed prove slower, then, the meteors path will have been closer to the ground along the inclined plane, and along a shallower angle.

      1. 48KM South of Revolution Square is too far South — that would place the contrail south of Yemanzhelinsk, which we know from videos it is not. If the meteor passed between Yemanzhelinsk and Korkino (as per the red line) then the distance south of Rev Square was 36km. With the angle of view from Revolution Square straight south established at 40 degrees (in the article above) then the height of the meteor at the time (which is also near when it was at its brightest) would be around 28km.

        1. In Emanzh glasses of window weren’t breaking down. As like in Epi of nuc.
          But in Korkino – yeeehhh.
          Here the wave of explosion is llayed flatling.
          The most breaked town is Korkino.

    2. actually, the speed of sound is slower at high altitude:
      330m/s at sea level, 0 Celsius
      295m/s between 12,000 and 20,000 m altitude (takes into account atmospheric variations of temp, humidity (i.e. density), if you re an experienced pilot you know that mach1 is slower ‘up there’ than ‘down here’ when looking at speed over ground).

      that’s a 10% variation, so the meteorite was probably blasting more around 17,000 to 18,000 meters than 20,000 (the curve speed of sound vs altitude is not linear)

  5. If this little-watched video is from Korkino, as noted by liilliil

    http://www.youtube.com/watch?v=odKjwrjIM-k

    near Rosa/Rosa, then the path or the meteor was slightly to the south of there. Likewise this one from Rosa/Roza:

    http://www.youtube.com/watch?v=Mwieex7gFAs

    ~23km south of Chelyabinsk. This shows the path of the meteor being a few km to the south.

    With some knowledge of shock wave propagation speeds at various altitudes, it should be possible to calculate the altitude and velocity of the meteor at this point.

    Another little-watched video with the smoke trail almost overhead:

    http://www.youtube.com/watch?v=64gXz9W2oyQ

    This is supposedly from Emanzhelinsk / Yemanzhelinsk, which is further south still. I think this shows the smoke trail to be somewhat to the north, with the initial view of the trail being at the western end.

    This would enable the track of the meteor to be located just a few km north of this location, somewhere between Korkino or Roza and Emanzhelinsk / Yemanzhelinsk.

    1. Yes, that Yemanzhelinsk video is also referenced by Sean Mac in his comments. I am updating the KML with the new estimates and will update the article shortly.

    2. You’re right, the videos tell us the meteor passed between Korkino and Yemanzhelinsk. For those of you reading along, Korkino is about 15km north of Yemanzhelinsk and 30km South of central Chelyabinsk.

        1. I want to note, at moment of Chelyabinsk Flash-mob temp is -10C/14F.
          And 15 high km sound have 295 m/s, and 10 km on the ground (average) is 310 m/s (at -10C/14F – 325 m/s)
          Total = (15kmx295+10kmx310) / 25 km= 301 m/s

          For other angle and path for heigt 25 km – velosity of sound is similar.

      1. Or meteor passing over Eman, but expl 5 km SEE from town.
        89 sec – its a Korkino (South sub of Korkino)
        10 km from epi and 25 km hegihts = 27 km / 0,3 km/s = 89,7 sec relay sound from expl.

  6. You’re working with video that has defined and known frame rate. This means that you could actually find out the speed of the meteor.

    1. Only if we know the distance, which we now do (see the update that I *just* published a moment ago.) But I need some sleep so perhaps I will leave it for an enterprising commenter:-)

  7. OK, let’s say you are able to figure out all the dynamics of this meteor strike, and let’s give you the stats on the next 1000 meteors after the fact as well. Think you could tell me which direction number 1002 will be coming from? We are nothing more then a moving target in a shooting gallery. Point is; enjoy life today, as tomorrow is just as uncertain as it was for the caveman.

  8. Speed of sound is dependent on temperature and as ambient temperature was below zero and temperature drops even more with height, the average speed of sound was around 300 m/s.
    From liilliil’s video it’s possibe to calculate distance of the meteore above the town where the video was taken. It took ~90 seconds to travel for the sound boom and it is pretty clear, that the nearest distance at that point was ~27000 m. This corresponds to the fact, that atmospheric density starts to grow rapidly below 30 km and that was the reason why the meteore expoded.

    1. Link? If the main piece didn’t fall there then a smaller chunk likely did. The main chunk, if it fell further afield along the same inclined plane, would make its angle of descent shallower.

    2. Yeep )
      perhaps its a suction maneuver of KGB )))
      On TV saying “not finding the parts”.
      But people not trusting them, )

  9. It is pretty obvious, that the main piece did not fall into Chebarkul.
    The opening in the ice cover was too small. The impact velocity was not so high, possibly as low as 400…500 km/h, but mass of the piece had to be way below 1000 kg. Otherwise the ice opening was much larger.

  10. Most possibly major part of the debris flew up to tens of kilometres ahead and the piece that fell into Chebarkul lake was only relatively small piece that was deviated from its course by the explosion. And it disintegrated even more due to impact and thermal shock when fell into cold water. So it is pretty hard to find some residues from the bottom mud.
    As fields in the area are covered by snow, it is pretty hard to find small impact traces of other pieces. If the meteorites have high metal content, then metal detectors could help to find debris.
    Population density of the landing zone seems to be very low, so it is almost impossible, that somebody will find some debris by chance soon.
    It seems that the rescue teams are searching in wrong areas because the correct route of the meteor is possibly not fixed yet. I have heard of 3 found impact zones, but the on in Chebarkul lake is the only published so far.

  11. Bolshoi Sarykul (Сарыкуль) – (Big) Yellow Lake.
    Sokolovo – Falcon (joke New Skolkovo)
    Posev (посев) – seeding of meteor parts
    Рикошет и Взрыв – Ricochet n Explosion
    излёт после рикошета – spent part afier ricochet

  12. You missing the fact that meteors path crosses the stright view of the video from Korkino, linked by liilliil

    Your path is pretty much parallel to the camera view.

    I think the meteor flew directy above the lake that is 2 km SE from Korkino. And explosion took place just above the lake.

    1. Where is this exactly?
      that remains to be seen.

      Im operating by videoclips with precision location on the map of city – crossroad, buolding.

        1. Thanks for that. I just checked the alignment in Google Earth with the existing red-line path and the angle corresponds very well. I’ll update KMZ file to reflect the more accurate location in Korkino shortly.

  13. Amazing work!
    Thank you for sharing
    something fell along the line after an explosion on a ballistic trajectory
    The lake is not the end point and the direction, azimuth.

  14. landed in Lake Chebarkul hoax have stated, the hole came for other reasons, and it was already announced that the meteorite was probably south of it at a considerable distance

    1. Looking at the light pole shadow, you can tell that the meteor travelled a little to the south of this location in Korkino, and elsewhere we know it travelled to the north of Yemanzhelinsk; Combine this with the view from RevolutionSquare and we pretty much fixes a point in space where we can tell the meteor was. Then, looking at the angle of the trajectory when looking up in the video at Yemanzhelinsk, we have a good idea of the direction it was heading — towards lake Chebarkul. A smaller piece may have dropped in Lake Chebarkul or nothing at all, but I think we now have multiple corroborating calculations that show the meteor traveling towards it.

      1. I realized.
        Exploded high, clearly in outline where and at what height, but after the explosion (the complete destruction of the falling object into fragments), then goes the free fall along a parabola, not a straight line. At the time of the explosion object loses kinetic energy, I think
        Do not want to believe that the object is completely destroyed, 10,000 tons of dust.
        Followed by painstaking work of scientists and searchers

  15. Look at this video, which is totally different from the other ones:
    http://www.youtube.com/watch?v=Z-BoS_YEhfg

    It was taken from Miass, abt. 90 km WSW of Chelyabinsk, or maybe 20 km west of Chebarkul, thus situated in the immediate direction of the meteorite path: it shows a white cloud, slowly billowing up (probably the impact site?) with a thin dark smoke trail leading towards it.

    1. Very interesting. Here is my interpretation. The dark line is not a smoke trail but the shadow from the sun to the east. The cloud itself is seen almost head on — i.e. heavily foreshortened — with a slight direction down and a little to the left, pointing to a location ENE of the viewpoint. THe meteor contrail is thus pointing almost directly at the viewer, aiming ENE of the viewer. That would corroborate the other sightings. Thanks for the heads up.

  16. Hi Stefan & JEM, I compared your path with the direction of the trail as seen from the satellite. Something seems wrong, as satellite data shows a heading to the WSW, and the reconstruction so far points toward WNW, because it make the asteroid on a collision course to the lake. But now, it doesn’t make sens to follow this point. In fact the trajectory can become flat! See the pic here:
    http://img580.imageshack.us/img580/6145/cheliabinsk.jpg

    1. Because Meteosat 9’s viewpoint is roughy aligned with the plane along which the meteor traveled, you can’t tell at what angle it was falling to Earth or if it was going parallel to Earth. However, other viewpoints on Earth do show the direction of the meteor (going WNW above Yemanzhelinsk as confirmed in this image https://ogleearth.com/wp-content/uploads/2013/02/abovehead.jpg), which allows us to deduce that the path was indeed aimed towards Earth.

      1. You’re right Stefan. I checked with a 3D Model of the Earth+Satellite. A horizontal one looks the same than an oblique one. That’s good news for fragments.

    1. Yeah, that was a very stupid news story. It’s obviously a man made hole, how could anyone think anything else? (Still, great analysis being made here! Of course it has to adapt to changing new information, but great work!)

      1. So, a man made hole, mysteriously instantly appearing, per local fishermen, with stone fragments around the hole sitting on the ice (and slightly melted into the ice)?
        Sorry, but something the size of a bowling ball, traveling 300kph or more, will do interesting things. Especially if it’s still hot from passing through the plasma from the fireball.

  17. The piece that fell into the lake was rather small. Most of the hole in the ice is caused by the water vawes, that appear to be almost symmetric around smal falling object. As energy of the waves decreases symmetrically, therefore waves break symmetric hole up to the diameter where waves are not strong enought to break the ice.

    It is unthinkable, that someone was able to create manmade hoe this big during that short time. Even using a chainsaws it is impossibe.

    1. Really? Would a meteor crashing through an icy lake really make a circular hole? And no cracks around it? I think fishermen saw such holes in the ice (the light gathers fish), and that one already existing was used as a hoax, or stupidly misunderstood.

      Sure, there’s ice thrown around, but maybe that is part of the process of sawing such fishing holes.

      1. If you look at the thickness of the ice above the waterline and apply the iceberg rule, the ice must be around a metre thick (In the Great Patriotic War, the Soviets drove tanks across lake ice). Like a bullet going through a metal plate, the meteorite is going to leave a circular hole through deformation more than making cracks, I think.

        Also, if the ice is that thick, consider how long it’s going to take to excavate a hole several metres acrosss using only hand tools, and then distribute the cutout chunks around the hole to resemble ejecta.

        1. I don’t think the ice is more than 20cm thick. In fact, it may be considerably less. Just look at those chunks of ice; they are rather small and look thin.

          Otherwise, I think it looks very natural, if you count as “natural” holes in ice made by falling space rocks. I’ve only seen holes made by high explosives and they sure are almost round just like this one.

      2. Could the ice be so tick and the fragment so small but
        warm, that fragment actually “landed” on the ice without cracking
        it, but then it gradually warmed up ice and water until fragment
        fall down, continued warming up water and created the hole AFTER
        falling? Or do fragments arrive to surface already cold? (I guess
        it depends on mass and material). This would cause a hole without
        ejecta.

        1. Fishermen said that they observed this moment: the stone
          broke the ice and caused large splash of water. Scientists also
          reported about clear signs of large directional splash of
          water.

        2. No, to melt that much ice, the meteorite would have to be immense, especially if it somehow managed to land softly enough to not vaporize ice, but hot enough to melt through and heat an immense amount of water.

          Meteorite fragments were found all around the hole, amongst the ejecta of fist sized blocks of ice.
          Something the size of a bowling ball, impacting at 300 kph or greater would create just such a hole. The mass causing the ice to fail, the pressure wave of displaced water creating an ejecta spray around impact and whatever remained intact after impact would embed itself in the silt at the bottom of the lake.
          Once the ice melts, they’ll eventually find the fragment.

          1. Why “immense”? It shouldn’t have to warm up whole lake, bringing water over 0°C for some minutes would have been enought to melt the ice just above the falling location.

            Anyway, now scientist suppose the fragment is around 200 kg, so it would have anyway caused a big hole, hot or cold!

            (this comment was posted by clicking REPLY directly at the bottom of the comment).

  18. Pingback: Disrupt « Stuff
  19. Of course waves did some cracks to the surrounding ice too. Meteorite itself most possibly did not. This is the same effect like if to shoot with a gun a small hole into the glass window. If the speed is fast enough, then remaining ice is not affected by meteorite. It is sure, that the impacted piece was rather small.

    I never saw any fisherman making hole so big. Whats the point of that? Even for fishing with a fishing net it is enough if a row of holes is drilled with regular ice drill. If water is only 3 m deep, so what is the point for making a hole with diameter of 9 m?

    BTW, ice fishing is one of my hobbies.

  20. Here is another view of the trajectory from a place easily identifiable. (photo)

    The location is also on Lenin Prospect, looking south. The wide angle view is taken from a window in this building:
    http://goo.gl/maps/r2gQR

    The photo confirms your analysis based on the lamp post shadows.

    I do however disagree with you on the rest of the analysis. The hole in the lake seems to be unrelated. No meteorite pieces have been found, so we cannot say where it landed, if anywhere.

    The trajectory based on the Meteosat-9 image matches almost exactly the line drawn on the street by the shadows – meaning that the fly-by trajectory must have been almost horizontal.

  21. If they searched with metal detectors, then the meteorite might be a stone type. Extremely hot stone falling into ice cold water might disintegrate almost completely. And as far it is known, that the bottom of the lake is muddy. It is hard to find smal pieces of rock from the mud.
    If this was iron meteorite, then it reached deep into the mud. And even with regular metal detector it is hard tu find it. Then sonar should help. I read, that there were divers searching. Then maybe they did not use a sonar?

  22. This was a great atmospherice blast test: I read somewhere that the energy released (i.e. what came out when it exploded, after having lost material already during the entry phase) was 470kT (nearly half a megaton of a blast).

    I did some quick calculations:
    assumption (which puts the result to a ‘low’ estimate since the volume is higher than actual):
    80m diameter ball of 5g/cm3 average density rocky stuff
    (you will see in the end that triple up or a third down won’t change the actual result at all, so don’t sweat it here – even if only 10% of the 80m ball were present the moment of the explosion, which released 470kT of energy: the numbers will then go up because the energy density will go up with less material, same blast energy)

    Blast release of 470kT energy, which is present in the ball right before the ball caves, and desintegrates releasing this excess stored energy

    Energy stored as heat in the ball (if ball was smaller then the energy density will go up)

    looked up some numbers like atomic particle density, and conversion of kT to eV

    Result:
    at the moment of the blast, the energy density in the (rest of) the 80m diameter meteorite comes up to about 10^10eV, or 10GeV per atomic particle (neglecting the cooling effect of the electron component, and not taking into account high energy electon collisions with nuclei either, so go down to 1GeV if you like for the energy in the nuclei)

    smashing atomic nuclei together at that energy is ample to cause some fusion, create some exotic nuclei only present in atomic reactors, certain supernovae, or like found around the Tunguska event

    Means:

    the energy density right before the blast was high enough to create exotic stuff while the thing was all together

    issue: for those type of nuclear reactions, ‘tunneling’ is the magic word: they happen with some probability even if a nominal energy is not yet reached (on average that is).

    I am not saying that the energy of this faint nuclear reaction part in the time right before the blast created the blast energy: nope
    But:
    there is a high enough energy density to generate these kind of ‘exotic’ materials.

    Why that idea?
    There are those ‘ufo sick’, and without a doubt, there was radioactive material found, and effects of damage on biological systems from it (trees that did not fall had radiation damage, external and from ingested radioactive materials).
    And, if near enough: these nuclear reactions, while not enough to alter the energy of the blast significantly, they do generate radiation, so if the blast is near enough, that radiation can have an effect: X rays from the ultra energized electrons, gamma rays from fusion reactions and immediate fissions of all kinds happening in that soup, which contains everything, from H to Si and beyond, locked together at an energy density of about 10GeV/atom (distribute between electons and nuclei if you want to do more detailed reaction probabilities.

    So: no UFO, space ship, or nothing needed but a really hot mad meteorite ready to blast with a megaton size bang (this one here was about 1/2 megaton, causing a measurable earthquake from the atmospheric blast wave)

    so interesting…….

  23. The blast energy was most possibly overestimated, because calculations were made expecting, that explosion took place at much higher altitude.

  24. OK, just found an update on the hole. http://www.rg.ru/2013/02/17/reg-urfo/okhotniki.html Depth at the place is 7 meters, thickness of the ice 70 cm. Mud layer is 1.5 meter deep. The previous statement from the initial search that they think it’s not related to meteorite is retracted. The visitors and the journalists were able to find tiny black pieces that stick to magnet. Scientists are planning to visit that place for more detailed research.

  25. The lake was covered with both ice and snow. Water that flooded surrounding ice on impact, did not melt the snow and gravity lead it vack to the hole.
    Cant you see that many pices of ice have thrown out of the hole? Those ice pices are on opposite side of the incoming meteorite. The other half of perimeter is clean. Just like expected.

  26. Great work, Stefan!
    I’ve also done similar calculations, but cannot prepare such visulalizations… :-( First of all, I’ve estimated the explosion altitude from several videos, where it’s possible to measure angles (by shadows of objects of known height) and sound delays from time-stamps. I prepared simple excel spreadsheet that calculates altitudes from delays, angles and ground temperatures (because my calculations also take into account dependencies of T°C on altitude in the atmosphere and sound speed on T°C). I’ve estimated explosion altitude as 27-30 km (and from that video from Korkino 27 km was the distance, i.e. for the angle 90°!). To say, I’ve tried to measure min. shadow length and height of light pole on the Revolution square more accurately: min. shadow length is ~17.5 m, height of light pole is ~13.5 m (from two good photos), so the angle is 38°. So, with altitude 27 km the explosion epicentre was at ~35 km approx. to the South from Revolution square. This place is located ca. 4-5 km to the South from Korkino, so was happy! :)
    I didn’t calculated precise 3D trajectory, but only proposed fly direction (almost E-W or tending to ESE-WNW).
    Sorry for my bad English…

  27. Good thinking Man. NASA with Billions in pocket will not tell, unless it is false. Keep improving the model.

  28. Been a regular visitor to this page last couple days fascinating to see the understanding develop. I have been interested in the audio side as it is more my field. Noticed several things will give one example which you may find interesting – The following 2 videos record 4 cracks (1 followed by 3 close together) in the 10 seconds after the initial bang 1. http://www.youtube.com/watch?v=-9HkE2RztYY 2. http://www.youtube.com/watch?v=18vF6aVWBgw (cracks meaning a distinct loud sharp sound like a rifle shot or a canon) and likely these two recordings close together. But these 4 cracks are not present in the 10 seconds after the bang in this Yemanzhelinsk video http://www.youtube.com/watch?v=64gXz9W2oyQ
    Seems like what was heard (recorded) in different places was not identical and varied according to location. Also possibly the initial bang sound that appears on all these videos is not actually a common starting time point. That was something I noticed anyway and a tentative initial conclusion. Not sure if looking at the audio side is useful in your reconstruction of the path but thought I’d mention it just in case it is interesting/useful to you or others.
    Anyway, thanks for your work on this and the commenters too I have found it very interesting reading,

    1. Quite a few of the YouTube videos have geolocation information. Has anyone tried triangulating using the time delay between the flash and the arrival of the sonic boom at each location? That, along with the work Stefan has done with shadows could be used to pinpoint the location of the blast. For example, with 3 separate videos, showing the shadow length and direction, we can get pretty close to the location of the blast. With a number of geolocated videos, the time delay between flash and sound could be used to confirm the shadow data. I’ve been looking for an analysis like that, and this blog is the closest I’ve found.

      For each video that contains the flash AND the bang!, determine the time of the maximum brightness (relative to the video, NOT the time stamp on the video, as that’s almost guaranteed to be wrong!). Then, either count frames until the beginning of the sonic boom or the first shards of glass start flying. That will be the delay time between flash and boom. From that, you can get the radius of a sphere with the center at the location where the video was recorded. Superimpose those spheres centered on the locations, and where they intersect should be pretty close to where the explosion occurred. Of course, that’s a rough location – shapes of streets/buildings, etc. would change the delay time, but I’d think that would be a rounding error and not very significant.

  29. Hi,

    Fascinating analysis!

    Reports here that at least one fragment of an Ordinary Chondrite has been found in the Lake Chebarkul area:

    http://www.spacesafetymagazine.com/2013/02/18/russian-meteor-latest-developments/

    Looks like a small fragment though so larger fragments may have travelled further; smaller ones may have fallen closer in.

    From the point of the explosion / sonic boom(s) the meteor broke up into possibly many pieces which would then travel on at different speeds to end up in different places, effectively a strewn field rather than a single impactor.

    Regards

    Simon

    1. This is really usefull glsmd. Could you make all the videos’s previews somehow visible in order to be able to go quicker through?

  30. Hi,

    Another video here showing a large crater on fire!

    https://www.youtube.com/watch?v=VEBF02kjjNw

    Not sure if this is genuine or not but compare with the size of the person in the opening shot.

    Also ESA has released video taken from orbit showing the debris trail moving with the winds:

    https://www.youtube.com/watchfeature=player_embedded&v=QCbLI-lb1QQ

    Perhaps this might give a clue as to prevailing wind speeds and help pin down the direction of travel.

    Kind Regards

    Simon

    1. That crater has been burning since 1971.

      It’s natural gas set alight by accident when mining.

      One Russian TV station showed the pictures and claimed the crater was caused by the meteor, adding fuel to the fire.

  31. Column of the water ice and steam was seen by the fishermen after the impact . I agree that thick ice was the reason that ice didn’t break . Samples around the hole are 100% space origin .
    Whole metal meteorite fraction does not exceed 10 percent by weight.
    According to recent studies by the Ural Federal University the basic is silicon and the metal component of the cosmic “alien” is quite rich. There is a zinc, nickel, iron, aluminum, magnesium, cobalt.
    http://www.rg.ru/2013/02/18/reg-urfo/sostav-anons.html

    1. Ok i just checked. The video shows that Kurgan is to the north of the contrail, ie the meteor passed to the south of Kurgan. On the map, if you draw a line from Chebarkul through Korkino and extend it, you see that it passes well to the south of Kurgan, just as the video has it. I take this as another confirmation.

  32. Sorry, I mean, The meteor was seen in Kurgan on the south, in your kmz should be seen on the north. Thank you!

    1. Hi all, I’m traveling today and while I can moderate comments I can’t do any checking up on new info as it arrives. But don’t wait for me… :-)

  33. The NASA infrasound network estimates the amount of energy freed, of about 500Kt TNT. Knowing the speed (18000m/s) allows to make a quick calculation with E = 1/2mV²
    This leads to a result of 13000 metric tons which is consistent with the figure given by NASA.

  34. Does anybody knows the real position of the military weather satellite “DMSP” that took the plume right in the minute after the desintegration? That could help to understand moore accurately the trajectory.
    In this view, the more western it goes, the more correct it is. Because of both the angles of satellite and meteor, the eastern side of the path is distorded to an unknown extend. Therefore, the need to know the position of DMSP: I could rebuild the view in 3D.
    http://img51.imageshack.us/img51/4624/dmsprussianmeteorview.jpg

  35. You can estimate height and speed using this video https://www.youtube.com/watch?v=2AiE9opBpTA

    This was recorded in Ekaterinburg, 200 km north. We’ve got two known points – tower of 188m height in front of us and church rightside. Distance between church and tower is 990 meters. We clearly see the object and the altitude it flies comparing to tower’s height. I think thats enough to estimate height )

    Finally we should add an extra – Earth is not flat and distance between sight line and surface 200km ahead will be about 2,5 km.

    And Xmas tree on the video you analyzed is 20m high.

  36. I also did a quick mapping and got very close, almost identical, to what this constructs. There’s another photo from the weather sat that shows a longer track, plus the border with Kazakstan. The track is dead parallel with the border and you can get dimensions from the border contours

    1. The photo you mention is what I used for the overlay in the KMZ file. It is also a view of the contrail from the same highly skewed perpective.

    1. It’d discussed elsewhere in the comment thread, but from the video itself it is impossible to independently locate the vantage point (other than from inference from the contrail).

  37. This is a highly interesting and well done analysis of the meteor trajectory! Impressive and well done! (for similar, but more detailed work on this method you might find interesting the work that was done on the Buzzard Coulee meteorite fall). One thing that strikes me as very odd is the proposed impact site on Lake Chebarkul. If the lake is truly on the intercept point of the trajectory with ground surface, then it would require the meteorite to retain most of its velocity. The largest fragment remains luminous for quite a distance after the main burst, but still disappears quite high above the ground (maybe >10 km?). This means the velocity fell below ~3 km/s, where ablation stops. After that it doesn’t take very long for the meteoroid to decelerate into free fall with terminal speed and fall short of the initial trajectory intercept point with the ground surface.

  38. To: SebastienP on February 18, 2013 at 20:35

    The position should be north of the centre of the frame as nearest edge of the frame should be shorter if the shooting direction is not completely perpendicular to the ground. So the start of the smoke trail is shifted southwards on this image.

  39. I’m confused a bit about distance/height estimations based on shock wave delays, especially for short distances (like for Korkino market-place video, where ~27 km can be easily obtained using speed of sound/air temperature dependence). Several people noticed me that explosion shock waves run with supersonic speed at first moments. I’ve also read this article about blast waves:

    http://en.wikipedia.org/wiki/Blast_wave

    where found the formula of G.I.Taylor that links explosion energy, time, air density and wave radius. Should it be taken into account in calculations of meteorite explosion distances?

      1. Thank you! I’ve already found this video (original version w/o editing) and used it in my calculations.

  40. To: comeT on February 19, 2013 at 11:44 said:
    “exact location 55°03′00″ N 60°06′00″ E”

    Unfortunately I can not recognise the place as the same from the video.

  41. To: Dmitry DD on February 19, 2013 at 11:53

    The explosion was not a detonation, it was actually a sonic boom. It can be called as explosion because the body of the meteor disintegrated almost instantly (during a few seconds) under heavy pressure and extream high temperature caused by resistance and friction in the air.

    1. The explosion was not sonic boom , it was detonation or explosion of the asteroid from the inside, caused by the inside pressure, caused by the temperature . Yes almost instantly .

      1. The explosion was indeed a sonic boom. Large bolides at hypersonic speeds produce very steep Mach cones, which essentially look like cylinders. There is no inside pressure in the meteoroid. There is a pressure gradient between the loaded front side and the back side. The thermal conductivity of the rock is not high enough for the inside of the meteoroid to heat up. It is a common misconception that meteorites are red hot when they impact the ground – in fact they are ice cold.

        1. I have yet another idea about sonic boom vs. shock waves. What are the main driving forces of shock waves? The large pressure difference (amplitude) and very steep pressure gradient, I think. May these parameters be achieved in front of large body with irregular shape that moves at speed about 15-20 km/s and enters the atmosphere? If “yes” then hypersonic shock waves are possible even if the body was not exploded itself but passively crushed by the air.
          To say, having enough precise and detailed measurements of sound delays, trajectory position and known atmosphere conditions, it’s possible to detect hypersonic shock waves by decrease of apparent calculated altitudes while approaching the trajectory. It is hypothesis only, may be wrong…

    2. Thank you! If I understood correctly, this explosion was too slow for hypersonic shock waves, therefore simple estimations based on speed of sound in the air are correct.

      To say, I prepared a small and simple excel worksheet for distance and altitude calculation for given sound delay, observation angle and ground temperature. It accounts dependencies of temperature on altitude and speed of sound on temperature. I’ve tried to publish this worksheet via google docs (it’s my first experiment with this service), the link is:

      https://docs.google.com/file/d/0BwwWPUHhxn2ESERRYXRsTUlWdk0/edit?usp=sharing

      I hope that formulae are correct there…

  42. One video posted with exact location
    54.984312, 60.106995
    http://www.youtube.com/watch?v=GiN1I2CK4gA

    another videos from Miass are interesting to
    http://www.youtube.com/watch?v=iwkKvLf3fZE
    http://www.youtube.com/watch?v=zMncbCbMbN8

    from : Уйское Челябинская обл
    http://www.youtube.com/watch?v=Bu4RuFg_v6U

    The first pictures from the surface of the fragments of a meteorite that fell into the lake Chebarkul
    http://www.rg.ru/2013/02/19/reg-urfo/mikroskop.html

    1. Wow, that first video is awesome: It looks at the contrail almost perfectly head-on AND it is located just beyond lake Chebarkul.

  43. I really, really wanted to do this, but I was stymied by the fact that I couldn’t get a read on a ground location to start from. I did spend a good hour looking around Chelyabinsk on Google Earth, and it seems like an interesting city.
    I had never seen the video that was used to measure the shadows. I’m glad to know that what I had in mind was indeed possible, and I’m also glad there are people with more tenacity than I. :)

  44. Could anyone tell me where this car camera was located please.

    I am interested in the bearing where the last piece of the meteor disappeared.

    1. It took me awhile to find it because the business names are unreadable and I stupidly didn’t expect it to be so far away, but I finally found it in Troitsk. The car was facing ПремьеРМЕД office and turned left at 54.07571, 61.53245 onto ulitsa Neplyueva heading NW. BTW the building the car was facing is not on Google Maps, see Yandex maps if you need

    1. I think it contains CO2 (from combustion with air in stratosphere), frozen water product from combustion (remember water is produced in combustion reaction) among others…

  45. Stefan,

    Do you think the smoke trail on this video passes directly overhead.

    I think the video is from Yetkul about 15km SE of Korkino.

  46. To: cliff mass on February 20, 2013 at 01:49
    The cloud should consist of fumes, ashes, vaporised and condensed material, small debris and dust (small particles released by friction and rapid temperature change). There should not be water (at least of cosmic origin).

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