We have completed our analyses and here’s what we know:
At 10:19 PM Central Daylight Time on August 2 (Saturday night), NASA meteor cameras detected a very bright fireball at an altitude of 57 miles above Hoodoo Road just east of the town of Beechgrove, TN. The meteoroid, which was about 15 inches in diameter and weighed close to 100 lbs, travelled just over 100 miles to the south south east at 47,000 miles per hour, breaking apart in a brilliant flash of light above the Alabama town of Henagar. The cameras continued to track a large fragment until it disappeared 18 miles above Gaylesville, located near Lake Weiss close to the Georgia state line. At last sight, the fragment was still traveling at 11,000 miles per hour. Based on the meteor’s speed, final altitude, and weak doppler radar signatures, it is believed that this fireball produced small meteorites on the ground somewhere between Borden Springs, AL and Lake Weiss.
The meteoroid’s orbit has its farthest point between the orbits of Mars and Jupiter, and is inclined to that of the Earth (which explains its southerly direction).
The NASA Meteoroid Environment Office would like to hear from those in the area around Alabama’s Lake Weiss who may have heard sonic booms or like sounds around 10:20 PM Saturday night. Please contact Dr. Bill Cooke at email@example.com if you have reports of such.
Last night at 8:38:30 PM CDT, a basketball size meteoroid entered the atmosphere 63 miles above Columbia, South Carolina. Moving northwest at 78,000 miles per hour, it burned up 52 miles above the Tennessee country side, just north of Chattanooga. This fireball was not part of any meteor shower and belongs to a class of meteors called Earthgrazers. These meteors skim along the upper part of the atmosphere before burning up. This one travelled a distance of 290 miles, which is quite rare for a meteor.
A bright first appeared 51 miles above the town of Dumas in northern Mississippi and proceeded slightly west of north at 40,000 mph, burning up between the Tennessee towns of Saulsbury and Middleton at an altitude of 23 miles. The time of the event was 12:46:36 AM CDT.
It was about as a bright as a crescent Moon, which translates into an object of about 6 inches in diameter. The orbit indicates that this meteor got as close to the Sun as the planet Venus and as nearly as far out as Mars before kamikazing into our atmosphere.
The NASA All Sky Fireball Network detected this beauty on May 16, 2013 at 03:11:50 UTC. Observed by 6 meteor cameras, this fireball penetrated deep into the atmosphere, making it down to an altitude of 36 km (22 miles).
A view of the fireball from Cartersville, Georgia. (NASA/MEO)
The 350 gram meteoroid responsible for this brilliant display entered the atmosphere at around 22 km/s (49,000 mph) — slow for a meteoroid! — and decelerated to about 10 km/s (22,000 mph) before disintegrating over northwest Georgia.
Map showing the location of 6 cameras in the NASA All Sky Fireball Network. Color-coded circles indicate the approximate field of view of each camera. The meteor’s path is shown in white. (NASA/MEO/D. Moser)
Calculations indicate a radiant in the constellation Libra.
Same meteor — same location — two different meteor cameras! The video shows the same meteor (an Eta Aquarid!) from one of our all-sky cameras and from our wide-field camera (~20×15 degree FOV) both located at Marshall Space Flight Center in Huntsville.
A composite image of 13 Eta Aquarid meteors from the NASA All Sky Fireball Network station in Mayhill, New Mexico the morning of May 6, 2013. Clouds seriously hampered our view of the ETAs this year. Observations reported to the International Meteor Organization indicate an outburst in the early hours of May 6th UTC.
This is the question that keeps cropping up, and it deserves an answer. Images are being posted showing the fragments and they look like ordinary chondrites of asteroidal origin. This material is dark, and not very reflective, which makes it difficult to spot out in outer space, especially if the object is bus or house size.
Astronomers measure brightnesses in magnitudes — the larger, more positive the number, the fainter the object is. The Sun is magnitude -27, the planet Venus -4, the star Vega 0, and the faintest star you can see is about +6. The best asteroid survey telescopes have a magnitude limit of about +24, which is about 16 million times fainter than what you can see with the unaided eye.
We can now use the latest orbit determined by Dave Clark (and yes, the meteor came roughly from the East, not from the North as stated in the initial NASA reports) and combine it with the estimated size and reflectivity to figure out when we should have seen the meteoroid in the asteroid survey telescopes. The calculations can be displayed in a graph like this one. Note that, even with very large telescopes, the meteoroid would not have been visible until a mere 2 hours (135,000 km from Earth) before impact — very little time to sound a warning.
Even if we had been looking at the right spot and the right time, there is another problem — the meteoroid would be in the daylit sky, and telescopes cannot see faint objects in the daytime.
Simply put, the meteoroid was too small for the survey telescopes and came at us out of the Sun.
According to NASA scientists, the trajectory of the Russian meteor was significantly different than the trajectory of the asteroid 2012 DA14, making it a completely unrelated object. Information is still being collected about the Russian meteor and analysis is preliminary at this point. In videos of the meteor, it is seen to pass from left to right in front of the rising sun, which means it was traveling from north to south. Asteroid DA14’s trajectory is in the opposite direction, from south to north.
This image shows asteroid 2012 DA14 and the Eta Carinae Nebula, with the white box highlighting the asteroid’s path. The image was taken using a 3″ refractor equipped with a color CCD camera. The telescope is located at the Siding Spring Observatory in Australia and is maintained and owned by iTelescope.net.
NASA experts will hold a teleconference for news media at 4 p.m. EST today to discuss a meteor that streaked through the skies over Russia’s Urals region this morning.
Scientists have determined the Russia meteor is not related to asteroid 2012 DA14 that will pass safely pass Earth today at a distance of more than 17,000 miles. Early assessments of the Russia meteor indicate it was about one-third the size of 2012 DA14 and traveling in a different direction.
Panelists for the teleconference are:
— Bill Cooke, lead for the Meteoroid Environments Office at NASA’s Marshall Space Flight Center in Huntsville, Ala. — Paul Chodas, research scientist in the Near Earth Object Program Office at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
The teleconference will be carried live online at: