If we took material like rock from space and got it back to Earth enough times, would Earth grow as a planet?
As the title says. I'm actually thinking about this hard with my friends because everything that's produced on Earth stays on Earth so it doesn't change size, but what if it's not from Earth but it stays on Earth?
As a kid I used to think that as leaves fall to the ground and decompose the earth just keeps getting bigger.
That doesn't answer your question, but there you have it.
Yes, this is called accretion. Planets and other solar system components grow this way from the dust and gas leftover from a star being formed.
Happens all the time, for eons. See: "shooting stars".
Earth gains 5200 tons each year from dust from space making it to the ground.
It seems like a lot but the Planet weights 65,000,000,000,000,000,000,000 tons.
This happens naturally in the form of meteors streaking through the sky. Each one of those is adding a tiny amount of mass to the planet.
But you've got me wondering about something now. When a large asteroid hits the planet, it obviously adds its own mass, but it also kicks up a lot of debris into space. Some percentage of that will reach orbital escape velocity and never come back. But I honestly don't know if there is a net mass increase or decrease after such an event? We're generally concerned about other more pressing matters in such a scenario!
unless the meteor is a rogue moon, the mass gained/lost is negligible compared to other particles interacting with the atmosphere or radiating (in and out), processes which are constantly happening.
for example, just the sun contributes some 200 tons every year (We also radiate out about the same mass that comes in). in 7.5 million years, that equals the asteroid that killed the dinossaurs (an event which happens way less often). So yeah, maybe the mass changes for a while, but even then, the dinossaur-killing asteroid is 0.000000000001% of earth's mass... If we had one meteor like that everyday for a billion years, we would get some 20% extra mass.
(rough numbers I calculated just know, double check please)
Yes the mass will change. It's a part of some Sci Fi tropes that for highly populated planets that the same mass of people coming on just match those coming off. Or else the planet will shrink or grow
What about all the mass and materials turned into satellites and rovers that have been sent off planet? Has Earth shrank?
https://www.universetoday.com/94392/getting-a-handle-on-how-much-cosmic-dust-hits-earth/
Every day tons of material comes into the earth's atmosphere. We do lose part of our atmosphere because of solar winds though.
This is one of those scenarios that humans have a much lower impact than nature.
Simple Answer: Yes.
Everytime we launch something into space the mass of Earth itself decreases by that amount. There is also energy trade off with the mass stealing a bit of earth's momentum/energy for it to continue as well.
Overall, we're talking about absolutely micro, if not smaller changes in mass and energy and it ultimately has zero affect on anything.
Would it really be a net negative though? Earth constantly has things burning up in the atmosphere. It turns into dust, gas and energy but it still is added.
Also long term you shouldn't have a negative change in mass. That would be against entropy
Earth only really loses it if it reaches escape velocity, otherwise it's still part of our gravity well... So basically, a handful of probes...
One of the proposed methods for terraforming Mars is to lob a bunch of icy rocks at it. That would increase its mass but more significantly also the energy of the falling rocks would convert to heat and melt the ice into water. So enough energy to increase Earth's size would also heat the surface and kill life.
You could pound it with astroids
You should maybe invite it to dinner first.
I mean yeah. If you add stuff to a ball of stuff it get's bigger.
Currently Earth is actually losing mass at around 55.000 tons per year. (100.000 tons loss due to air escaping to space but gaing around 45.000 tons in dust and meteorties falling on it).
Katamari intensifies
La~ lalala-lala-la-la-la Katamari Damashi~
If “energy equals mass”, shouldn’t we be gaining mass from the sun too 🤔
We do. The sun's energy is locked in plants via photosynthesis, which is then processed by herbivores and passed further down the food chain. That energy exists in form of chemical compounds which are then broken down to release it during digestion.
In terms of numbers tho, it's probably a negligible fraction of the Earth's mass
We do, an infinitely small amount. Remember you gotta divide by c².
> energy equals massThat doesn't mean energy has a weight.It means it is physically possible to transition energy to mass and vice versa. Sunlight hitting the earth does not add any weight.Edit: turns out that part was wrong
Also, earth radiates heat out to space. At a rate of (aaaaaaaaalmost, because of the greenhouse effect) 100% of the energy we get from the sun. If it didn't, earth would be a few million degrees hot by now...