Where to start-lol. I'll address your post by paragraph but try to answer everything so this is a long post, sorry. Be it remembered that this video was made in 2012 and wasn't discovered until a recent playback if I understand correctly. The names in parens. are names of named meteorites
Witnessed falls of meteorites arrive frequently which are this (apparent) size and smaller, were no fireball or sonic boom is reported. Several reasons come into play. Sonic booms do not propagate above 42 miles(?) owing to air density where sound waves can exist AND would have occurred several minutes before AND certainly lost in the noise of flight and headsets.
As to no fireball report, the apparent fall trajectory was very near the sun, even when not near the sun, witnessed daylight fireballs are very rare and usually only associated with very large entering bodies/masses. Meteorites falling at steep angles make less "noise" than those falling at a more shallow angle. Peeskill's fireball tracked over western Kentucky several minutes all the way to New York yet no one heard a sonic boom nor even a noise until it wacked a parked car.
Remember the size you are seeing is the size left over after ablation. The original mass was much larger but all meteorites are a reminent of a larger mass, whether or not it fragments. Depending on the altitude of fragmentation, the resulting fall pattern is usually scattered over a very broad area. I know one field 33 miles long. Some are longer some shorter but rarely under 2 miles on axis. The number of meteorites within a fall depends on how large the original body, how well it fragmented and at what altitude fragmentation began(how late or early in the ablation cycle). Excepting for certain falls (e.g Allende, Pultusk, Stantern, Hoolbrook etc) where the meteorites fell as "peas" in a meteorite showers, rarely are distinct stones found close to each other to be in the same typical frame of a photograph/video.
Stone distribution is effected by the angle of entry. To visualize the variability: Take a flashlight at chest high point it at the floor( 90°) at your feet and note the circular profile. Point the light out at 45° and note the pattern is a large oval 3-4 times larger in area. Repeat with the flashlight at your knees. Now the area illuminated is .2% of the area when held at your chest. This is how strewn fields patterns on the ground. The bottom line is that the fall ellipse/oval changes with the height and degree of fragmentation(s) plus the angle of entry. The number of meteorites found in the ellipse is constrained by the degree of fragmentation and surviving mass of material.
The remaining size(s) after ablation stops can range from 65 tons ( Hoba) down to 10 micrograms but 20-40-250grams-to 2kg is a typical bell curve of weights. Note that the smaller the fragment the faster it loses kinetic energy and the faster it reaches retardation speed(i.e. stops incandescing/glowing and ablating) and enters "dark flight"-- slowing to terminal velocity which varies by weight and cross section of each stone. No more than 400mph and more often 200- 120mph-ish± assumeing a typical-sized stone.
As to ablation and temperatures: Meteoroids arrive at the top of the atmosphere cold-- very cold-- like -120° to -400° cold. Ablation(i.e. melting where molten meteorite is carried away in the slip stream) is an evaporative cooling process. The melted iron/silicate is constantly removing heat about as fast as it accumulates; So well that when we analyze them they show no heating above 160°F just 5mm below the surface. As they fall in dark flight through very chilled air for several minutes in most cases, they arrive warm on the surface but quickly can form frost rinds. Westfield CT fell through a roof and when found under the dinning room table it was covered with frost. As strage as it seems, owing to many factors such as heat transfer coefficients and evaporative cooling via ablation of melted silicate, etc, newly fallen stoney meteorites are at most warm to the touch before turning cold--Irons, which have better heat transfer, do retain more heat so can be uncomfortable to hold. Meteroies do NOT start fires or "glow several days under water", contrary to reports I've reviewed. Re-itteration: even thought it is 1400-4000° outside just under the surface it is still in deep freeze.
A point meteor is one of the ones you have to worry about because you are dead on to its trajectory at the point you see it but, as it is on a curve, even then is not likely to shower your immediate area you --unless it is directly over head. All the others are no danger to you. Incidentally if you do see a meteor/fireball rising in the sky it is passing over head and you are under its flight path--several miles below but such an observation helps know where to hunt,( Neuschwanstien--yes, near the castle, which I helped hunt in Germany in 2012 brag brag) One of our teams found the watermellon-sized mass. Another smaller mass was found a few years later
For dynamics and air density reasons, meteors under a meter original size cannot keep ablating under 5 miles above sea level. So after the fireball phase a meteorite has to fall 5 or more miles to sea level. Perception-wise for various other physiological and psychological reasons of how the eye and brain process fast moving bright light no one--NO ONE I know of including myself, can estimate the size, distance or location of a fireball. It takes ground-based technical cameras and satellites to compute size, speed, trajectory and probable fall location IF anything was likely to survive to become a meteorite. I've worked with those data packages many times over the years. Speed and light output are worked backwards to find what sized mass was converted into light and heat then the probable derivative mass which might remain to get original mass and sometimes orbital data! Neat technology.
You are not alone as it happens to us all. " It seems like it fell right over the barn, the tree, the hill etc." Before I understood this I also spent a lot of time looking just over the barn myself! There is no reliable scale of reference so the brain runs home to something familiar and fills in the blanks. A meteor which disappears at "ground level" is about 200-250 miles away! The scooting could have been reflection through or along high level clouds. I've interviewed a many witness and they all believe legitimately that they were going to be hit--"it was so close". Large fireballs can release energy on par with small atomic bombs. Without a calibrated eyeball we can't tell where the fireball was headed until after the event.
Eman
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Witnessed falls of meteorites arrive frequently which are this (apparent) size and smaller, were no fireball or sonic boom is reported. Several reasons come into play. Sonic booms do not propagate above 42 miles(?) owing to air density where sound waves can exist AND would have occurred several minutes before AND certainly lost in the noise of flight and headsets.
As to no fireball report, the apparent fall trajectory was very near the sun, even when not near the sun, witnessed daylight fireballs are very rare and usually only associated with very large entering bodies/masses. Meteorites falling at steep angles make less "noise" than those falling at a more shallow angle. Peeskill's fireball tracked over western Kentucky several minutes all the way to New York yet no one heard a sonic boom nor even a noise until it wacked a parked car.
Remember the size you are seeing is the size left over after ablation. The original mass was much larger but all meteorites are a reminent of a larger mass, whether or not it fragments. Depending on the altitude of fragmentation, the resulting fall pattern is usually scattered over a very broad area. I know one field 33 miles long. Some are longer some shorter but rarely under 2 miles on axis. The number of meteorites within a fall depends on how large the original body, how well it fragmented and at what altitude fragmentation began(how late or early in the ablation cycle). Excepting for certain falls (e.g Allende, Pultusk, Stantern, Hoolbrook etc) where the meteorites fell as "peas" in a meteorite showers, rarely are distinct stones found close to each other to be in the same typical frame of a photograph/video.
Stone distribution is effected by the angle of entry. To visualize the variability: Take a flashlight at chest high point it at the floor( 90°) at your feet and note the circular profile. Point the light out at 45° and note the pattern is a large oval 3-4 times larger in area. Repeat with the flashlight at your knees. Now the area illuminated is .2% of the area when held at your chest. This is how strewn fields patterns on the ground. The bottom line is that the fall ellipse/oval changes with the height and degree of fragmentation(s) plus the angle of entry. The number of meteorites found in the ellipse is constrained by the degree of fragmentation and surviving mass of material.
The remaining size(s) after ablation stops can range from 65 tons ( Hoba) down to 10 micrograms but 20-40-250grams-to 2kg is a typical bell curve of weights. Note that the smaller the fragment the faster it loses kinetic energy and the faster it reaches retardation speed(i.e. stops incandescing/glowing and ablating) and enters "dark flight"-- slowing to terminal velocity which varies by weight and cross section of each stone. No more than 400mph and more often 200- 120mph-ish± assumeing a typical-sized stone.
As to ablation and temperatures: Meteoroids arrive at the top of the atmosphere cold-- very cold-- like -120° to -400° cold. Ablation(i.e. melting where molten meteorite is carried away in the slip stream) is an evaporative cooling process. The melted iron/silicate is constantly removing heat about as fast as it accumulates; So well that when we analyze them they show no heating above 160°F just 5mm below the surface. As they fall in dark flight through very chilled air for several minutes in most cases, they arrive warm on the surface but quickly can form frost rinds. Westfield CT fell through a roof and when found under the dinning room table it was covered with frost. As strage as it seems, owing to many factors such as heat transfer coefficients and evaporative cooling via ablation of melted silicate, etc, newly fallen stoney meteorites are at most warm to the touch before turning cold--Irons, which have better heat transfer, do retain more heat so can be uncomfortable to hold. Meteroies do NOT start fires or "glow several days under water", contrary to reports I've reviewed. Re-itteration: even thought it is 1400-4000° outside just under the surface it is still in deep freeze.
A point meteor is one of the ones you have to worry about because you are dead on to its trajectory at the point you see it but, as it is on a curve, even then is not likely to shower your immediate area you --unless it is directly over head. All the others are no danger to you. Incidentally if you do see a meteor/fireball rising in the sky it is passing over head and you are under its flight path--several miles below but such an observation helps know where to hunt,( Neuschwanstien--yes, near the castle, which I helped hunt in Germany in 2012 brag brag) One of our teams found the watermellon-sized mass. Another smaller mass was found a few years later
For dynamics and air density reasons, meteors under a meter original size cannot keep ablating under 5 miles above sea level. So after the fireball phase a meteorite has to fall 5 or more miles to sea level. Perception-wise for various other physiological and psychological reasons of how the eye and brain process fast moving bright light no one--NO ONE I know of including myself, can estimate the size, distance or location of a fireball. It takes ground-based technical cameras and satellites to compute size, speed, trajectory and probable fall location IF anything was likely to survive to become a meteorite. I've worked with those data packages many times over the years. Speed and light output are worked backwards to find what sized mass was converted into light and heat then the probable derivative mass which might remain to get original mass and sometimes orbital data! Neat technology.
You are not alone as it happens to us all. " It seems like it fell right over the barn, the tree, the hill etc." Before I understood this I also spent a lot of time looking just over the barn myself! There is no reliable scale of reference so the brain runs home to something familiar and fills in the blanks. A meteor which disappears at "ground level" is about 200-250 miles away! The scooting could have been reflection through or along high level clouds. I've interviewed a many witness and they all believe legitimately that they were going to be hit--"it was so close". Large fireballs can release energy on par with small atomic bombs. Without a calibrated eyeball we can't tell where the fireball was headed until after the event.
Eman
On Thursday, April 10, 2014 9:26 AM, Lin Kerns <linkerns@gmail.com> wrote:
The one problem I have with this story is that of size. If said meteor fell through the atmosphere, then is should be the remnant of a much larger chunk of space rock. If that is not the case, then a meteor of that size should've burned up upon entry of our atmosphere.
But for the sake of argument, let's suppose that the meteor IS part or a remnant of a larger meteor; if that is the case, shouldn't there have been a contrail or an explosion (aka a fireball) or a thermal signature from a larger, parent meteor burning upon entry? Wouldn't someone have heard it or seen the fall? Instead, we are told that the meteor had already cooled from its entrance into our atmosphere, so that the aforementioned small article of debate simply flew past the skydiver on its way to earth without any fanfare. I cannot believe that. Just cannot wrap my head around it.
But for the sake of argument, let's suppose that the meteor IS part or a remnant of a larger meteor; if that is the case, shouldn't there have been a contrail or an explosion (aka a fireball) or a thermal signature from a larger, parent meteor burning upon entry? Wouldn't someone have heard it or seen the fall? Instead, we are told that the meteor had already cooled from its entrance into our atmosphere, so that the aforementioned small article of debate simply flew past the skydiver on its way to earth without any fanfare. I cannot believe that. Just cannot wrap my head around it.
What about the composition of the meteor, you might ask? Nickel/Iron burns just as readily as a chondrite upon entering our atmosphere, especially if the meteor is that small. Friction from speed of entry into the thicker layer of atmosphere would not allow any size meteor to effectively cool as it neared earth. Instead it should simply ignite and vaporize.
Why this bothers me to such an extent is that I thought I was a goner from a meteor strike. When I first spotted it, I'm sure it was as large as a house, but as it fell, the fireball lost more mass until by the time it was near the ground, its diameter was about 6'. Heat kept it from falling, as it slid along heated air, parallel to the ground until it burned completely. In short, it vaporized (my conclusion, as we couldn't find any trace of it later). That was one time I thought I was going to have to change my pants, because at first, I believed that speed and trajectory of the meteor was not going to let me live beyond that night.
Thanks,
Lin
On Wed, Apr 9, 2014 at 7:29 PM, MEM <mstreman53@yahoo.com> wrote:
So I am waiting until everyone has a "final final position" before reversing mine opinion that it is possible to catch a falling meteorite on video. ( In fact one of the Chelyblinsk security cam videos caught a stone falling off a roof as well as the impact of the main mass falling through the ice of a lake but how soon we forget)
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