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The paper from this article says that only 450kg of charged material from meteorites enters the relevant part of the atmosphere each year. Yet the total amount

The paper from this article says that only 450kg of charged material from meteorites enters the relevant part of the atmosphere each year. Yet the total amount of meteorites entering is somewhere in the range of 10^7 to 10^9kg per year [0]. I know the really small stuff slows down too quickly to burn up completely, but does anyone know why such a small fraction of the meteorites burns up in this region compared to satellites? Or is that 450kg number just wrong? [0] https://www2.tulane.edu/~sanelson/Natural_Disasters/impacts.htm https://www2.tulane.edu/~sanelson/Natural_Disasters/impacts....

mlindner 3y ago
The number sounds wrong. Most meteorites are made of conductive material. And I've never heard of small meteors not burning up. The energy still has to go somewhere.
soco 3y ago
But burning up doesn't make them disappear - the resulted compounds will still be in the atmosphere. Doesn't that matter?
- Kerbonut 3y ago
  That’s tomorrow’s problem! /s
- simne 3y ago
  > the resulted compounds will still be in the atmosphere Why you think so?
martinclayton 3y ago
Bottom end of the range: 10^7Kg per year would be about 27.5 tonnes per day. The article references another piece[1] where they quote 54t per day, a similar number. There's then an estimate made of how much of that is Aluminium - 1%. I guess the author ran the 54t / 100 calc and came up with 0.45 instead of 0.54 ... a simple typo. The key point is most of the natural stuff doesn't hang around up there. Top end (10^9 Kg) of the range we get about 2750t per day natural origin. And at 1% for Aluminium that's 27.5t per day. That number is not far off the 29t estimated daily burn for the full Starlink v2 constellation they quote. Also: I notice that the Lodders article focussed specifically on Aluminium as it had been proposed as a method for geoengineering albedo. There are other metals in the natural origin material, and I don't see why we should exclude those from affecting the Van Allen belts - is it only Aluminium that's bad? Comparing the Starlink burn to the Van Allen material mass seems irrelevant when there's perhaps a few hundred tonnes per day of naturally arriving metals around too. It's not obvious to me this topic can be waved away as not an issue though. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8137964/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8137964/

mlindner 3y ago

The number sounds wrong. Most meteorites are made of conductive material. And I've never heard of small meteors not burning up. The energy still has to go somewhere.

soco 3y ago

But burning up doesn't make them disappear - the resulted compounds will still be in the atmosphere. Doesn't that matter?

Kerbonut 3y ago
That’s tomorrow’s problem! /s
simne 3y ago
> the resulted compounds will still be in the atmosphere Why you think so?

martinclayton 3y ago

Bottom end of the range: 10^7Kg per year would be about 27.5 tonnes per day. The article references another piece[1] where they quote 54t per day, a similar number. There's then an estimate made of how much of that is Aluminium - 1%. I guess the author ran the 54t / 100 calc and came up with 0.45 instead of 0.54 ... a simple typo. The key point is most of the natural stuff doesn't hang around up there. Top end (10^9 Kg) of the range we get about 2750t per day natural origin. And at 1% for Aluminium that's 27.5t per day. That number is not far off the 29t estimated daily burn for the full Starlink v2 constellation they quote. Also: I notice that the Lodders article focussed specifically on Aluminium as it had been proposed as a method for geoengineering albedo. There are other metals in the natural origin material, and I don't see why we should exclude those from affecting the Van Allen belts - is it only Aluminium that's bad? Comparing the Starlink burn to the Van Allen material mass seems irrelevant when there's perhaps a few hundred tonnes per day of naturally arriving metals around too. It's not obvious to me this topic can be waved away as not an issue though. [1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8137964/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8137964/