6. All of the atoms and molecules that make up the earth and its atmosphere travel around that sun, at an amazing speed, spinning at the same time. And we don’t lose an atom or a molecule. How can that be???
Gravity.
There is nothing new under the sun.
” ... And we don’t lose an atom or a molecule. How can that be???”
It can’t be.
Thousands of tons (circa 1970 estimate: 10,000 tons) arrive every day, mostly micrometeoroids drawn by our planet’s gravitational field.
Now and then, a bigger object - say, as big as a small grain of sand - arrives and vaporizes, leaving a painfully brilliant track across the night sky (if it chances to enter the atmosphere on our planet’s night half). Sometimes, we see it, but it lasts only a second or so. Lighter elements join the other gases in the atmosphere; heavier ones get down to the surface. Eventually.
Every once in a great while, a much larger object arrives. Lucky for us, the intervals between such are very, very long.
Things are pretty busy at the molecular level too.
Our planet is constantly blasted by the radiation from our sun. Visible light is only the tiniest fraction of the electromagnetic energy that hits. A deluge of particles hits as well; their great velocity breaks molecules into atoms, knocking apart the hydrogen and oxygen of water, splitting the paired nitrogen and oxygen atoms that form most of our air, breaking the carbon away from the two oxygen atoms that formed carbon dioxide. Freshly loosed atoms can be bounced away with such high velocity that they never return. The rest mix into the atmosphere, or fall still lower.
Fortunately (for us and the other living things, mostly on or near the surface), our planet’s core spins, creating a magnetic field that deflects most of those speedy particles, and the deep blanket of the atmosphere absorbs most of the radiation, or reflects it elsewhere.
Goodly amounts of air and water still exist here on earth, held (mostly) by gravity, boosting surface air pressure to a level that lets us continue breathing. So the loss of millions upon millions of individual molecules isn’t too serious.
All this goes on all day, every day. So do many other things. Lucky for us, we don’t have to pay any of it much attention.
Hope it stays that way.