Awesome Fireball Event in central Russia

2012 DA14 may not be on a collision course with Earth later today but a smaller asteroid was. A major fireball (and most likely also a meteorite dropping event) occurred over the city of Chelyabinsk, Russia. Chelyabinsk is a city of 1+ million people located just to the East of the Ural Mountains and just north of the Russia-Kazakhstan border.

The fireball that occurred there this morning appeared brighter than the Sun and produced a sonic boom that shattered windows causing flying glass-induced injuries to hundreds of people. A large building in town also seems to have been damaged. Though it is still uncertain if this was due to a large meteorite or the sonic boom.

An event like this happening only hours before the close flyby of the ~45-meter in diameter asteroid 2012 DA14, begs the question of whether the two are linked. It is probably unlikely that the Chelyabinsk fireball and 2012 DA14 are related. Luckily there are so many great videos of the fireball that an accurate orbit for the asteroid that caused the fireball should be easily determined.

[Update: 2012 DA14 and the Russian fireball can not be related. The radiant (the region of the sky that a DA14 or a piece of DA14 would appear to come from) of DA14 is at the very far southern declination of -81 degrees. This is the reason why DA14 is only visible from the southern hemisphere as it approaches Earth. A radiant that far south could not produce a fireball over Russia which is in the northern hemisphere. Any pieces of DA14 would only be able to impact Earth over the southern hemisphere or a few degrees north of the Equator. The fact that the Russian fireball and the 2012 DA14 close approach are happening on the same day is just a coincidence.]

Up-to-date information can be found at RT, here and here, and RMNB.

Many videos have been posted. The first 2 show the fireball itself. The last 2 are videos of the resulting contrail. What is very impressive about the last two is that the videos also caught the sonic boom. In one of the videos you can hear glass shattering in the background. Simply awesome…

Update on the Wisconsin Fireball (and meteorites)

A brilliant and well observed fireball was observed flying over the American Midwest Wednesday evening. The map below shows that sightings were made from Kansas in the south to Minnesota in the north and from Indiana in the east to South Dakota in the north. The yellow stars denote a sighting while the red stars denote reports of sonic booms (a tell tale sign that meteorites may have survived to hit the ground).

Map of fireball and sonic boom reports for the April 15 Wisconsin fireball. All reports were submitted to the Amercian Meteor Society and this blog. Yellow stars denote sightings and red stars denote sonic boom reports. Credit: Carl Hergenrother

Zooming in on the area where most of the sonic booms were heard brings us to southwestern Wisconsin. We now know that meteorites were found in this area. Not only did the sonic booms  and the large number of videos point meteorite hunters to this area but as many as 3 NWS Doppler radars picked up the meteorites as they were falling through the atmosphere. The blue square pinpoints were the radars place the most likely area of meteorite falls.

Zoomed in map of fireball and sonic boom reports for the April 15 Wisconsin fireball. All reports were submitted to the Amercian Meteor Society and this blog. Yellow stars denote sightings, red stars denote sonic boom reports and the blue square denotes most likely point of meteorite landings. Credit: Carl Hergenrother

All of these observations have allowed researchers to quickly find meteorites from this fireball. Meteorite related stories can be found here and here.

Finally a YouTube video of the fall…

Meteorite Found?!! – June 23 AZ fireball

Jack Schraeder of Sierra Vista, AZ has reported finding a probable meteorite from June 23rds fireball over southern Arizona. He made his announcement of the find on the meteorite-list user group. A picture can be found at the Rocks From Space site.

According to the Rocks From Space site, the meteorite is a brecciated H chondrite weighing 155.6 grams (5.5 oz). It was found ~45 hours after the fall which corresponds to the evening of Thursday June 25. No info has been released on the location of the find or whether any additional meteorites have been found.

Meteors in the News – DoD Classifies Fireball Data and Boy Gets Hit By Meteorite

Two news stories related to meteors hit the news wires the past few days.

Military Hush-Up: Incoming Space Rocks Now Classified

On Thursday came a story about the United States Department of Defense (DoD) classifying data on fireballs. Specifically data taken by their Defense Support Program satellites that monitor the world for signs of missile launches. As it turns out, these satellites were also very good at detecting bright fireballs as they “burn up” in the Earth’s atmosphere. For the past 15 years, the DoD has been sharing fireball data with the scientific community. For some examples, a collection of releases for past fireballs can be found here.

More than 15 years ago, the DoD’s fireball data was classified. This now appears to be the case once again. I have yet to see an official reason for this, though usually the real movie behind classifying information has less to do with the object itself but rather, what the data can tell others about the detection capability of our satellites. Perhaps it has something to do with our soon-to-be upgrade to a newer, more sensitive constellation of satellites. The Space-Based Infrared System (SBIRS) is the DoD’s next generation system and it is possible that the DoD would like to keep its capabilities hush for awhile.

Regardless, the loss of this data to science isn’t too bad. We will still be able to detect and study fireballs over a good fraction of the world. This is becoming more and more possible due to the proliferation of low light camera systems operated by astronomers and for security purposes.

14-year-old hit by 30,000 mph space meteorite

Yesterday’s story comes out of Essen, Germany. There is a report that a 14 year old boy was struck by a meteorite on the hand. As reported by The Telegraph, the boy stated that “At first I just saw a large ball of light, and then I suddenly felt a pain in my hand. Then a split second after that there was an enormous bang like a crash of thunder. The noise that came after the flash of light was so loud that my ears were ringing for hours afterwards. When it hit me it knocked me flying and then was still going fast enough to bury itself into the road.”

Getting hit by a meteorite is an extremely rare event. There is only one documented case, that being of a woman from Alabama being struck back in 1954. So being hit is not impossible. Still the story out of Germany has some inconsistencies.

The meteorite is said to be very small, only the size of a pea. No problem there. It is also reported that it struck the boy on the hand. Again unlikely but no problem. Everything else about the story is problematic.

First let’s run down what a meteorite fall would look like. Many people have seen Hollywood’s version of a meteorite fall. Great examples include the CGI meteors in many of Michael Bay’s movies (Transformers, Armageddon). The meteors are portrayed as relatively small but crashing to the ground at a low angle at 1000’s of miles per hour. They are usually flaming with smoke trails behind them. The meteorites then crash through buildings, bridges, whatever. This is true for large objects.

For your “run-of-the-mill” meteorite-dropping  fireball (fragments up to the size of a volleyball), the event will look very different. The original small asteroid will hit the atmosphere at velocities of ~10-70 km/s. Its passage through the atmosphere is violent as air is compressed in front of it in a bow shock. Eventually there comes a point when the pressure is too great and the meteoroid starts to fragment. On many occasions there is a final disruption event. It is usually at this point when the meteoroid has broken into much smaller pieces that a bright flash, or terminal flash, is seen and sonic booms are heard. The sonic boom are caused by the small meteoroid pieces decelerating rapidly below supersonic speeds due to atmospheric drag. So great we have a loud noise and a bright flash just like those mentioned in the German article. Problem is, all of this happens tens of miles up.

So here’s some problems with the “meteorite hits boy” account:

  • 30,000 mph space meteoroid“: Well, yes and no. The meteorite might have been traveling 30,000 mph when it first hit the atmosphere but it was moving much, much slower by the time it hit the ground. After disrupting into smaller pieces, the pea-sized meteorite would have been in free fall from a height of many tens of miles or kilometers. Air drag would slow it to its terminal velocity which for a pea-sized rock is rather slow, slower than the speed limit on most highways.
  • saw a large ball of light“: The fireball produced by the meteoroid traveling through the atmosphere would have been bright enough to see even during the day. But, it would have been seen over many 100’s of miles, and I know of no other sightings. Also the fireball would have ended when the meteoroid disrupted. That means the fireball would have ended many tens of miles up and many minutes before the pea-sized piece hit the ground. A rock of that size would have taken a few minutes to fall from 20-40 miles up. When it did hit the ground it would have looked no different then if a small rock had been thrown off of the top of a building.
  • enormous bang like a crash of thunder“: Again any sonic boom caused by the fireball would have occurred many minutes before the meteorite hit the ground. Also those sonic booms would have been heard over many tens of miles.
  • When it hit me it knocked me flying and then was still going fast enough to bury itself into the road“: Not likely since it was traveling so slow. There is a German article that shows the size of the meteorite and its resulting “crater”. You can see it here. Again, a meteorite this small would have hit the ground too slowly to do any damage to the ground. The meteorite would have simply bounced along the ground.

So what does this story tell us? Either it’s a complete hoax and there never was a meteorite fall. Yes, it’s true that researchers in Germany have confirmed that the rock is a meteorite but that doesn’t mean much yet. Anyone purchase a small legit meteorite of this size off of Ebay for a few dollars. It is also possible that this is a real meteorite fall and the boy’s “story” is fabricated. Maybe to live up to many people’s incorrect idea of what a meteorite fall would look like.