I’m wondering whether the mass of the earth has changed significantly since it was formed and became stable. By earth I mean the big round mass and everything that rests upon it. If it makes a difference either way feel free to include/exclude the atmosphere. By stable I mean when the earth turned into something we would recognise now - oceans and flourishing land masses.
What I’m thinking is that apart from major ejections such as possibly the moon, the earth should have had a relatively stable mass. Impacts have added to the weight - but as a minor fraction of the total mass I assume.
What really got me to thinking about this was the e=mc^2 part of nuclear explosions. I can’t think of anything else energetic enough to have directly converted mass to energy that it likely to have occurred.
Then there are the objects which we’ve pushed into space - again incredibly small as a percentage of the earths mass.
I also thought about combustion - my understanding is that when I burn, for example, wood, the combustion products have the same mass as the wood did. After all energy cannot be destroyed, only converted from one form to another. But, would the resultant gases mix with the atmosphere and then does some of the atmosphere “drift” into space. I recall that gravity keeps it mainly in place but is there an analogue to evaporation where atoms or molecules gain enough kinetic energy to escape gravity and drift into space?
I’m beginning to think there are two questions here - change in mass and behaviour of the upper layers of the atmosphere.
Why “earth”? Anyway, it has grown. I think I read somewhere that a thousand tonnes of water alone are thought to enter the earth’s atmosphere every day. Of course, this is still infinitesimal in terms of the mass of the earth (but not, perhaps, of the ocean). The earth probably receives about as much energy from the sun as it radiates out to space (otherwise the temperature would rise until that happened), so energy gains and losses do not contribute significantly to this.
What could happen if we chose ‘natural gas’ as our next energy producer and emptied the Earth’s internal cavities of such; as we are now doing with oil (and water somewhat)?
Is the Natural Gas protecting the voids beneath from colossal collapse?
I think it has gained mass. The net gain from meteorites that hit the surface is much greater than the net loss from whatever methods cause it to lose mass (nuclear fission, man-made materials being sent into space, what have you.)
They don’t even have to hit the surface — if they burn up in the atmosphere, they’ve still added to the mass of the earth, just in finely pulverized & oxidized form.
We also lose a small amount of mass continuously, primarily hydrogen & helium produced via radioactive decay (and which are too light to stick around in the atmosphere for long.) Estimating either one of these numbers, though, is rather tricky, and I’ll leave it as an exercise for someone else.
This is a pretty common question. Here is one answer from a site for kids:
“Earth is about 4.6 billion years old. So figure 4.6 billion years times 500 million kilograms. That’s about 2.3 x 1015 tons of meteorite mass, or about 1/2,000,000 of the Earth’s current mass. So yes, Earth would definitely have gotten heavier over the past 4.6 billion years.”