5 ms·

Is every place being slowly buried likewise? Is the planet slowing getting thicker? Where does all this material come from?

bbarnett 5y ago
Human skin is 99.9% of the dust in most homes. (had to reply with a gross out amusement, it's not sand, it's dead people!)
- anoncow 5y ago
  I used to believe that too. However, apparently there is more to it https://www.sciencefocus.com/science/what-is-dust-made-of/ https://www.sciencefocus.com/science/what-is-dust-made-of/ Also this video by Derek is very informative https://youtu.be/jn5M48MVWyg https://youtu.be/jn5M48MVWyg
- bryanrasmussen 5y ago
  >Human skin is 99.9% of the dust in most homes. Sure, ever since Thanos.
rustymonday 5y ago
In the case of Egypt it's mostly wind-blown sand and dust. But deposition can also be caused by river sedimentation during floods. In non-desert areas, dead biomass (fallen leaves, etc.) creates soil. My parents had a stone path through their yard that they didn't maintain, and within a decade it was covered over with soil and grass grew over it. Over the course of a few thousand years, structures can be buried by several meters of earth.
- AlotOfReading 5y ago
  The speed of deposition is super variable. In fluvial environments, I've seen reports of feet per year, which put recent sites (i.e. medieval) under 40+m of sediment. On the other hand, I've worked sites with long term 'stable surfaces', where layers thousands of years old were within centimeters or less of modern contexts.
saalweachter 5y ago
Organic matter largely comes from the air. Inorganic matter largely gets blown from other places, or washed down from mountain tops.
speeder 5y ago
Replying your specific question, actually the planet is slowly getting rounder. A simplification of the process: Tectonic plate movements create mountains, as they climb on top of each other (and where space was opened, lava there turns into new rock) Then erosion carry material from high places, to low places. Thus over time places in high areas get "shorter", while places in low areas get "taller". Meanwhile some parts of tectonic plates are sinking again and melting again. But as the planet core cools down, this process get slower and slower, and erosion speed remains "constant", so over time the tendency is the planet get rounder and rounder, eventually the planet would have cooled 100% and no new mountains would form, while erosion would make all mountains become flat over time.

bbarnett 5y ago

Human skin is 99.9% of the dust in most homes. (had to reply with a gross out amusement, it's not sand, it's dead people!)

anoncow 5y ago
I used to believe that too. However, apparently there is more to it https://www.sciencefocus.com/science/what-is-dust-made-of/ https://www.sciencefocus.com/science/what-is-dust-made-of/ Also this video by Derek is very informative https://youtu.be/jn5M48MVWyg https://youtu.be/jn5M48MVWyg
bryanrasmussen 5y ago
>Human skin is 99.9% of the dust in most homes. Sure, ever since Thanos.

rustymonday 5y ago

In the case of Egypt it's mostly wind-blown sand and dust. But deposition can also be caused by river sedimentation during floods. In non-desert areas, dead biomass (fallen leaves, etc.) creates soil. My parents had a stone path through their yard that they didn't maintain, and within a decade it was covered over with soil and grass grew over it. Over the course of a few thousand years, structures can be buried by several meters of earth.

AlotOfReading 5y ago
The speed of deposition is super variable. In fluvial environments, I've seen reports of feet per year, which put recent sites (i.e. medieval) under 40+m of sediment. On the other hand, I've worked sites with long term 'stable surfaces', where layers thousands of years old were within centimeters or less of modern contexts.

saalweachter 5y ago

Organic matter largely comes from the air. Inorganic matter largely gets blown from other places, or washed down from mountain tops.

speeder 5y ago

Replying your specific question, actually the planet is slowly getting rounder. A simplification of the process: Tectonic plate movements create mountains, as they climb on top of each other (and where space was opened, lava there turns into new rock) Then erosion carry material from high places, to low places. Thus over time places in high areas get "shorter", while places in low areas get "taller". Meanwhile some parts of tectonic plates are sinking again and melting again. But as the planet core cools down, this process get slower and slower, and erosion speed remains "constant", so over time the tendency is the planet get rounder and rounder, eventually the planet would have cooled 100% and no new mountains would form, while erosion would make all mountains become flat over time.