The Chelyabinsk "Meteorite"

reply to post by JrDavis


did you not see my working earlier in the thread or did you just choose to ignore it? theres no way the rock was travelling 33000mph, max 4000mph!

Originally posted by connelly4245
I've worked it out now! lol. you've changed the distance of 10350m into a speed of 23152mph

-snip-

theres no chance something in earths atmosphere could travel that speed

JrDavis may be wrong on multiple levels in this thread, but let's have a closer look at the speed:

Since meteor speeds are usually measured in km/sec it'll be easier to work in these units.

23152 mph translates to 37,260 km/h

(37,260/60)/60 gives us 10.35 km/s

This speed actually falls well within the speed range a large meteoroid/asteroid can travel through the atmosphere at, given that they usually enter the atmosphere at speeds ranging from 11 km/sec to 72 km/sec (25,000 mph to 160,000 mph), and are then significantly slowed down by the atmosphere:

12. How fast are meteorites traveling when they reach the ground?

Meteoroids enter the earth’s atmosphere at very high speeds, ranging from 11 km/sec to 72 km/sec (25,000 mph to 160,000 mph). However, similar to firing a bullet into water, the meteoroid will rapidly decelerate as it penetrates into increasingly denser portions of the atmosphere. This is especially true in the lower layers, since 90 % of the earth’s atmospheric mass lies below 12 km (7 miles / 39,000 ft) of height.

At the same time, the meteoroid will also rapidly lose mass due to ablation. In this process, the outer layer of the meteoroid is continuously vaporized and stripped away due to high speed collision with air molecules. Particles from dust size to a few kilograms mass are usually completely consumed in the atmosphere.

Due to atmospheric drag, most meteorites, ranging from a few kilograms up to about 8 tons (7,000 kg), will lose all of their cosmic velocity while still several miles up. At that point, called the retardation point, the meteorite begins to accelerate again, under the influence of the Earth’s gravity, at the familiar 9.8 meters per second squared. The meteorite then quickly reaches its terminal velocity of 200 to 400 miles per hour (90 to 180 meters per second). The terminal velocity occurs at the point where the acceleration due to gravity is exactly offset by the deceleration due to atmospheric drag.

Meteoroids of more than about 10 tons (9,000 kg) will retain a portion of their original speed, or cosmic velocity, all the way to the surface. A 10-ton meteroid entering the Earth’s atmosphere perpendicular to the surface will retain about 6% of its cosmic velocity on arrival at the surface. For example, if the meteoroid started at 25 miles per second (40 km/s) it would (if it survived its atmospheric passage intact) arrive at the surface still moving at 1.5 miles per second (2.4 km/s), packing (after considerable mass loss due to ablation) some 13 gigajoules of kinetic energy.

On the very large end of the scale, a meteoroid of 1000 tons (9 x 10^5 kg) would retain about 70% of its cosmic velocity, and bodies of over 100,000 tons or so will cut through the atmosphere as if it were not even there. Luckily, such events are extraordinarily rare.

All this speed in atmospheric flight puts great pressure on the body of a meteoroid. Larger meteoroids, particularly the stone variety, tend to break up between 7 and 17 miles (11 to 27 km) above the surface due to the forces induced by atmospheric drag, and perhaps also due to thermal stress. A meteoroid which disintegrates tends to immediately lose the balance of its cosmic velocity because of the lessened momentum of the remaining fragments. The fragments then fall on ballistic paths, arcing steeply toward the earth. The fragments will strike the earth in a roughly elliptical pattern (called a distribution, or dispersion ellipse) a few miles long, with the major axis of the ellipse being oriented in the same direction as the original track of the meteoroid. The larger fragments, because of their greater momentum, tend to impact further down the ellipse than the smaller ones. These types of falls account for the “showers of stones” that have been occasionally recorded in history. Additionally, if one meteorite is found in a particular area, the chances are favorable for there being others as well.

Source: The American Meteor Society Meteor Shower FAQs

We also know that at some point, usually between 15 to 20 km (9-12 miles or 48,000-63,000 feet) altitude, the meteoroid remnants will decelerate to the point that the ablation process stops, and visible light is no longer generated. This occurs at a speed of about 2-4 km/sec (4500-9000 mph).

So given this bit of info, and the footage which shows the end point of the meteor in some cases, we can safely say that the meteoroid/s or asteroid/s were slowed down to 2 km/s (4500 mph) just by looking at a single video.

Originally posted by connelly4245
the energy created would be tremendous due to the earths atmosphere!

Which is exactly what occurred - energy equivalent to 500 kilotons of TNT was released in the blast, and the meteor itself outshone the Sun (probably even before the main blast).

Just throwing my 2 cents in regarding the size, speed and impact. I was reading about it on Nasa.gov

And their most recent estimates are

New information provided by a worldwide network of sensors has allowed scientists to refine their estimates for the size of the object that entered that atmosphere and disintegrated in the skies over Chelyabinsk, Russia, at 7:20:26 p.m. PST, or 10:20:26 p.m. EST on Feb. 14 (3:20:26 UTC on Feb. 15). The estimated size of the object, prior to entering Earth's atmosphere, has been revised upward from 49 feet (15 meters) to 55 feet (17 meters), and its estimated mass has increased from 7,000 to 10,000 tons. Also, the estimate for energy released during the event has increased by 30 kilotons to nearly 500 kilotons of energy released. These new estimates were generated using new data that had been collected by five additional infrasound stations located around the world – the first recording of the event being in Alaska, over 6,500 kilometers away from Chelyabinsk. The infrasound data indicates that the event, from atmospheric entry to the meteor's airborne disintegration took 32.5 seconds. The calculations using the infrasound data were performed by Peter Brown at the University of Western Ontario, Canada.

Not a good thing to happen in a populated area

Wow... lol, seems to me the easiest way to explain why the OP is confused by the video is he is looking at it all wrong. Sonic boom? This wasn't a jet flying overhead.. you heard and saw the effects of a massive shock wave, it had nothing to do with sonic booms really. Take that into consideration and let me know if you still think something's amiss.