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> scattered small meteorites on the ground at the impact site about 37 miles (60 kilometers) west of Berlin Do we know how fast those small meteorites are trav

by jl6 3y ago

> scattered small meteorites on the ground at the impact site about 37 miles (60 kilometers) west of Berlin Do we know how fast those small meteorites are travelling when they hit the ground? Are they like bullets or more like snowflakes?

sfn42 3y ago
They're rocks, so at least like rock hail.
awb 3y ago
Somewhere in between, but probably closer to bullet speed. There are numerous accounts of meteorites entering people’s houses. Here’s a recent one: https://abcnews.go.com/US/scientists-confirm-meteorite-crash-landed-new-jersey-home/story?id=99285587 https://abcnews.go.com/US/scientists-confirm-meteorite-crash... It pierced the roof but didn’t pierce the floor.
- tutfbhuf 3y ago
  If it can pierce a roof, then it can pierce the human body as well, so it's pretty deadly.
somenameforme 3y ago
You can very roughly estimate the lower bound pretty easily, by assuming a meteorite to be roughly spherical and ballparking the drag coefficient. So its volume = 4/3 * pi * r^3. Its surface area = 4 * pi * r^2. We can assume half of its surface area is its cross section. So just change the 4 to a 2 above to get the cross sectional area. Meteors generally have a density up to around the 8000 kg/m^3 range. So now we have everything we need to calculate terminal velocity using a calculator. [1] for a 1m meteorite: mass = 4/3 * pi * 0.5^3 * 8000 = 4188 kg area = 2 * pi * 0.5^3 = 0.78 m The defaults for density and drag coefficient are fine enough. And we get a result of at least 500m/s, assuming air resistance is sufficient to slow it down to terminal velocity. The exact number will vary quite a lot - especially as this is for a whole meter sized meteorite that doesn't disintegrate, but this is at least a reasonable ballpark. So the tl/dr would be: more like a bullet, but with somewhere around 140,000 times the kinetic energy, for a 1m meteorite. [1] - https://www.gigacalculator.com/calculators/terminal-velocity-calculator.php https://www.gigacalculator.com/calculators/terminal-velocity...
goku12 3y ago
I assume that the pieces get enough time to decelerate to terminal velocity after its fragmentation and explosion in the upper atmosphere. If so, it would be like rocks falling from a great height - not supersonic, but you wouldn't want to get hit by one. One nitpick here - meteors aren't called meteorites until they hit the surface.

by jl6 3y ago

sfn42 3y ago

They're rocks, so at least like rock hail.

awb 3y ago

Somewhere in between, but probably closer to bullet speed. There are numerous accounts of meteorites entering people’s houses. Here’s a recent one: https://abcnews.go.com/US/scientists-confirm-meteorite-crash-landed-new-jersey-home/story?id=99285587 https://abcnews.go.com/US/scientists-confirm-meteorite-crash... It pierced the roof but didn’t pierce the floor.

tutfbhuf 3y ago
If it can pierce a roof, then it can pierce the human body as well, so it's pretty deadly.

somenameforme 3y ago

You can very roughly estimate the lower bound pretty easily, by assuming a meteorite to be roughly spherical and ballparking the drag coefficient. So its volume = 4/3 * pi * r^3. Its surface area = 4 * pi * r^2. We can assume half of its surface area is its cross section. So just change the 4 to a 2 above to get the cross sectional area. Meteors generally have a density up to around the 8000 kg/m^3 range. So now we have everything we need to calculate terminal velocity using a calculator. [1] for a 1m meteorite: mass = 4/3 * pi * 0.5^3 * 8000 = 4188 kg area = 2 * pi * 0.5^3 = 0.78 m The defaults for density and drag coefficient are fine enough. And we get a result of at least 500m/s, assuming air resistance is sufficient to slow it down to terminal velocity. The exact number will vary quite a lot - especially as this is for a whole meter sized meteorite that doesn't disintegrate, but this is at least a reasonable ballpark. So the tl/dr would be: more like a bullet, but with somewhere around 140,000 times the kinetic energy, for a 1m meteorite. [1] - https://www.gigacalculator.com/calculators/terminal-velocity-calculator.php https://www.gigacalculator.com/calculators/terminal-velocity...

goku12 3y ago

I assume that the pieces get enough time to decelerate to terminal velocity after its fragmentation and explosion in the upper atmosphere. If so, it would be like rocks falling from a great height - not supersonic, but you wouldn't want to get hit by one. One nitpick here - meteors aren't called meteorites until they hit the surface.