METEOR, 15.2.13, ~9.22 Ortszeit, Tscheljabinsk, Tjumen, Swerdlowsk, Russland !!!

[karmaka]

Die  Volkssternwarte Streitheim hat nun auch ihr prächtiges Chelyabinsk-Exemplar (508g), wie die Augsburger Allgemeine heute berichtet: 

Herzlichen Glückwunsch an Hr. Mayer!

FOTO

LINK

Und noch schnell zur Erinnerung:

Sonderausstellung Im Rieskratermuseum in Nördlingen ist noch bis Sonntag, 24. November, eine Sonderausstellung über den Meteoritenfall im Februar zu sehen: „Chelyabinsk 2013 – Warnschuss aus dem All?“ Das Museum hat dienstags bis sonntags von 10 bis 12 und von 13.30 bis 16.30 Uhr geöffnet.

[KarlW]

Dankeschön an den rasenden Reporter Martin! 

Solange gibt's im Rieskratermuseum auch noch den Fall Braunschweig zu sehen, vgl.:

http://www.augsburger-allgemeine.de/noerdlingen/20-Kilometer-pro-Sekunde-id27630477.html

[karmaka]

Qing-Zhu Yins neue Chelyabinsk Scans

VIDEO-LINK

VIDEO-LINK

This movie presents X-ray computed tomographic (CT) data for Chelyabinsk fragment 3-3-4. The first rotation shows surface rendering of the collected CT data, with both the fusion crust and fractures prominent on its exterior. Upon the second rotation, the surface is made transparent to reveal the interior components of the sample presented in a blue-green volume rendering (color bar shown). This visualization is achieved by adjusting the threshold over the nominal full range from 0 to 65,535 that scales with the absorption coefficient of the material. The lower threshold for the volume rendering starts low and is increased to 22,000 to hide the fine grain matrix materials made of low density, low Z elements. The upper threshold was adjusted to 55,670 to provide the best contrast for objects of interest. When the lower threshold is static at 22,000 in the movie, components displayed are metal (FeNi alloy) and troilite (FeS) (shown in green collectively), and finely disseminated FeNi and FeS grains intermingled with silicates (shown in blue). Finally the sample is rotated showing the peak end of the stone towards the viewer. The sample is then cut through the rock virtually showing the individual X-ray CT slices (a total of 1,176 slices encompass the sample in this slice direction; the CT data was reconstructed into 5.46 micron isotropic voxels). Typical ordinary chondritic textures can be discerned readily, such as chondrules (seen as dark rounded objects in the serial slices, rich in low-Z elements, e.g. O, Mg and Si), as well as metal and troilite grains (bright white, irregularly shaped grains). A network of fractures, likely due to the highly shocked nature of the meteorite, is also apparent throughout the rock's interior. The X-ray CT imaging was performed at the Center for Molecular and Genomic Imaging at the University of California, Davis, with a MicroXCT-200 scanner (Xradia, Inc.) The X-ray CT data is rendered using the software Amira 5.4 (VSG Inc.).

[karmaka]

The trajectory, structure and origin of the Chelyabinsk asteroidal impactor

    Jiří Borovička, Pavel Spurný,   Peter Brown, Paul Wiegert, Pavel Kalenda,   
    David Clark & Lukáš Shrbený

Nature  (2013) doi:10.1038/nature12671, Published online 06 November 2013

LINK

Earth is continuously colliding with fragments of asteroids and comets of various sizes. The largest encounter in historical times occurred over the Tunguska river in Siberia in 1908, producing1, 2 an airburst of energy equivalent to 5–15 megatons of trinitrotoluene (1 kiloton of trinitrotoluene represents an energy of 4.185 × 1012 joules). Until recently, the next most energetic airburst events occurred over Indonesia3 in 2009 and near the Marshall Islands4 in 1994, both with energies of several tens of kilotons. Here we report an analysis of selected video records of the Chelyabinsk superbolide5 of 15 February 2013, with energy equivalent to 500 kilotons of trinitrotoluene, and details of its atmospheric passage. We found that its orbit was similar to the orbit of the two-kilometre-diameter asteroid 86039 (1999 NC43), to a degree of statistical significance sufficient to suggest that the two were once part of the same object. The bulk strength—the ability to resist breakage—of the Chelyabinsk asteroid, of about one megapascal, was similar to that of smaller meteoroids6 and corresponds to a heavily fractured single stone. The asteroid broke into small pieces between the altitudes of 45 and 30 kilometres, preventing more-serious damage on the ground. The total mass of surviving fragments larger than 100 grams was lower than expected7.

Figures and tables index

Table 1: Trajectory of the Chelyabinsk superbolide

Extended Data Figure 2: Light curve of Chelyabinsk superbolide in relative units and fragmentation altitudes as determined from sonic booms.

Extended Data Figure 5: Identification of fragments in a series of images from video 7

Extended Data Figure 6: Dynamics of the dust trail and fragments and predicted impact positions of observed fragments. 7

Extended Data Figure 7: Images of the dust trail at early stages.

Extended Data Table 1: List of YouTube videos used

Figure 1: Ground projection of the terminal part of the bolide trajectory and meteorite-strewn field

Main trajectory (thick red line) and trajectory of fragment F1 (thin orange line) as plotted on Google Earth. The marks denote altitudes in kilometres. The predicted impact positions of 11 observed fragments (F1–F4, F6, F7 and F11–F15) are shown. The impact positions of simulated small (non-observable) fragments are also given. Yellow dots denote fragments that separated at lower altitude (21–26 km), pink fragments originate in the main break-ups at 30–39 km and brown fragments are from break-ups above 40 km. The three dot sizes correspond to terminal masses of 1–10 g, 10–100 g and >100 g. The second largest fragment, F2, had an estimated mass of 30 kg based on its observed deceleration. The dynamics after luminous flight ceased30 (dark flight) was computed using the wind field from the nearest available radiosonde at Verkhnee Dubrovo (180 km north of Chelyabinsk) measured at 0:00 ut on 15 February 2013. Using the wind field measured by radiosonde at Kurgan (250 km east of Chelyabinsk) would shift the meteorites much more to the south (by 2.5 km for a 200-g meteorite). The position of the impact hole in Lake Chebarkul (marked ‘Crater’) and the centroid of strewn field of small meteorites13 are also shown. See also Extended Data Fig. 4. We expect that, as in other cases11, the mass distribution will be more complicated and the strewn field will be larger than our idealized model predicts.

Extended Data Figure 4: Predicted impact position of fragment F1, computed with four different wind fields, compared with the position of the hole in the ice (‘Crater’).

The point marked F1 was computed with Verkhnee Dubrovo radiosonde data (0:00 ut). Point K is for Kurgan radiosonde (0:00 ut), point U is for the UKMO wind model for Chelyabinsk (12:00 ut) and point G is for the G2S model (3:00 ut) (ref. 31 in Supplementary Information). The distance between U and K is 960 m. The distance between F1 and the crater is 220 m. We note that the position of the crater was not used for the computation of the F1 trajectory and impact point. The background image is from Google Earth and was taken one day after the impact.

[aknoefel]

Das ganze als Zusammenfassung in Deutsch::

http://www.n-tv.de/wissen/Meteorit-explodierte-wie-30-Atombomben-article11675896.html

[karmaka]

Hier wird das oben bereits öfters erwähnte Video von Nikolaj Mel'nikov nun vom Seti-Institute noch einmal in voller Länge gezeigt:

VIDEO-LINK

Und tatsächlich ist die beim Impakt um 03:21:34.7 UT entstandene Eisstaubwolke dort zu sehen! 

[karmaka]

Nachtrag:

Die Entfernung zwischen Kamera und Einschlagsort im Eis beträgt übrigens 2451 Meter.

[aknoefel]

Telepolis-Artikel: "Unerwartet gewaltiger Einschlag"

http://www.heise.de/tp/artikel/40/40270/1.html

[aknoefel]

Beitrag aus wissenschaft.de: "Kosmische Sprengladung"

http://www.wissenschaft.de/erde-weltall/geowissenschaften/-/journal_content/56/12054/2426778/Kosmische-Sprengladung/

[Thin Section]

Heute in unserer lokalen Tageszeitung.

Bernd 

[Greg]

Danke für die ganzen Links. 

Sehr interessant finde ich die Grafiken in dem Nature Artikel.
Durch die Referenzpunkte in den Bildern wird das ganze viel deutlicher.
Und natürlich die Lichtkurve in Relation zu den Überschall-Knallen. 

Grüße 
Greg

[karmaka]

Hier ist das Impaktvideo noch einmal in einer leicht veränderten Fassung zu sehen:

VIDEO-LINK

Im gestrigen Science Magazine Podcast sagte Jenniskens übrigens (ab 4:20 Min. Laufzeit), dass die Geschwindigkeit der Masse beim Aufschlag auf dem Eis 225 Meter pro Sekunde betragen haben soll.

AUDIO-LINK

Zwischen dem 'Schatten des Meteors' um ~03:20:32 UT und dem eigentlichen Aufprall um 03:21:34.7 UT auf dem Eis vergingen also ~ 62,7 Sekunden.

[karmaka]

Dies muss noch dringend nachgereicht werden.

Spannendes zum Thema für Augen und Ohren:

Chelyabinsk Airburst, Damage Assessment, Meteorite Recovery, and Characterization

Olga P. Popova, Peter Jenniskens, Vacheslav Emel'yanenko, Anna Kartashova, Eugeny Biryukov, Sergey Khaibrakhmanov, Valery Shuvalov, Yurij Rybnov, Alexandr Dudorov, Victor I. Grokhovsky, Dmitry D. Badyukov, Qing-Zhu Yin, Peter S. Gural, Jim Albers, Mikael Granvik, Läslo G. Evers, Jacob Kuiper, Vladimir Kharlamov, Andrey Solovyov, Yuri S. Rusakov, Stanislav Korotkiy, Ilya Serdyuk, Alexander V. Korochantsev, Michail Yu Larionov, Dmitry Glazachev, Alexander E. Mayer, Galen Gisler, Sergei V. Gladkovsky, Josh Wimpenny, Matthew E. Sanborn, Akane Yamakawa, Kenneth L. Verosub, Douglas J. Rowland, Sarah Roeske, Nicholas W. Botto, Jon M. Friedrich, Michael E. Zolensky, Loan Le, Daniel Ross, Karen Ziegler, Tomoki Nakamura, Insu Ahn, Jong Ik Lee, Qin Zhou, Xian-Hua Li, Qiu-Li Li, Yu Liu, Guo-Qiang Tang, Takahiro Hiroi, Derek Sears, Ilya A. Weinstein, Alexander S. Vokhmintsev, Alexei V. Ishchenko, Phillipe Schmitt-Kopplin, Norbert Hertkorn, Keisuke Nagao, Makiko K. Haba, Mutsumi Komatsu, Takashi Mikouchi (the Chelyabinsk Airburst Consortium)

The asteroid impact near the Russian city of Chelyabinsk on 15 February 2013 was the largest airburst on Earth since the 1908 Tunguska event, causing a natural disaster in an area with a population exceeding one million. Because it occurred in an era with modern consumer electronics, field sensors, and laboratory techniques, unprecedented measurements were made of the impact event and the meteoroid that caused it. Here, we document the account of what happened, as understood now, using comprehensive data obtained from astronomy, planetary science, geophysics, meteorology, meteoritics, and cosmochemistry, and from social science surveys. A good understanding of the Chelyabinsk incident provides a unique opportunity to calibrate the event, with implications for the study of near-Earth objects and developing hazard mitigation strategies for planetary protection.

Originally published in Science Express on November 7 2013 on
ScienceExpress DOI:10.1126/science. 1242642

Pflichtlektüre. Die 146 Seiten starken supplementary materials !!! :

PDF-LINK

Hier ist noch das Transkript zum Science Podcast zum Mitlesen:

PDF-LINK

Nature Podcast 7.11.13 - Impact factor  - The asteroid that shook a Russian town in February

AUDIO-LINK

BBC - Science in Action - Asteroid Hit-Rate Underestimated

AUDIO-LINK

[herbraab]

Ich hab’ schon ein bisserl den Überblick verloren, aber ich denke, dieses verbesserte Video des Einschlags wurde hier nich nicht verlinkt, oder?
Interessant ist insbesondere der Zeitraffer ab 1:00, wo man die von der Einschkagstelle abziehende "Wolke" recht gut sehen kann, die beimEinschlag aufgewirbelt wurde.

http://youtu.be/DZy_tmSsILM


Herbert

[aknoefel]

Beitrag im Tagesspiegel: "Angriff aus dem All"

http://www.tagesspiegel.de/wissen/meteoriten-angriff-aus-dem-all/9050738.html