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?
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.
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).
add stuff to a ball of stuff it gets bigger
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, an infinitely small amount. Remember you gotta divide by c².
Isn’t this just a matter of units though?
Like we could define our own units such that 1 unit of e equals 1 unit of m.
I have no clue what units that c2 formula are actually in 😕
I have no clue what units that c2 formula are actually in 😕
c is the speed of light, so you can use any distance over time unit. But most commonly it’s given as 299 792 458 m/s
Like we could define our own units such that 1 unit of e equals 1 unit of m.
So you can’t since m is multiplied by c and c isn’t equal to 1.
Actually you can.
Oof - I have to rethink everything I thought I knew about E=mc2 🫠
I’ve always discounted c2 as “just a number” and didn’t consider it was a number of specific units 🫣
I’ve always discounted c2 as “just a number” and didn’t consider it was a number of specific units 🫣
This is actually very common and I even remember physics teacher basically using the words “don’t worry about it, it’s just a really big number”, because their point was to imaging the big amount of energy you could get from very little mass.
But I mostly blame old documentaries about atom bombs that just threw in the absolute basics to make what is basically explosion porn.
I even remember physics teacher basically using the words “don’t worry about it, it’s just a really big number”
Ok - This is literally the origin for me. My 8th grade “physical science” teacher told us this.
> 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…
Energy don’t have weight but, it does have an effect on the curvature of space the same way matter does. In fact one of the proposed methods to create artificial blackholes is to put enough photons into the same place. It’s easier than getting matter together as photons don’t interact with eachother.
However the point is correct that light energy will only impart an insignificant amount to the earth’s pull.
Oooh…Good point. And now I have conflicting responses.
This one makes the most intuitive sense to me but ¯\_(ツ)_/¯
One more thing to connect both responses.
Energy itself doesn’t have mass. Mass is interchangeable. But we do gain mass by a very kittle amount when it is stored (by plants or solar panels you know). So both answers checks out. Mass can be converted to large amount of energy and large amount of energh can be converted to little amount of mass.
That doesn’t mean energy has a weight.
No, it literally does mean that. If you put light in a box of mirrors the total weight of the box will literally increase by an amount equal to the energy of the photons. If you put some radioactive material in a theoretically perfectly sealed box from which no heat or light could escape, and weigh it while it decays into radiation, the weight will not change.
This applies to all forms of energy. A spring is heavier when compressed. An object gets heavier when you spin it, or heat it up. Sunlight hitting the earth most definitely makes it heavier. In fact, the sun hits the earth with about 4.4*10^16 watts of power, corresponding to about 0.5 kilogram per second.
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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
I thought plant biomass was obtained from the air (CO2/carbon sequestration?) and water.
You need photosynthesis to do that
Sure, but the implication was that plant mass comes from the sun. Maybe some negligible fraction of percent is but nowhere near the majority.
The sun’s energy also goes into heat all over the planet. I’m just trying to understand how any of that energy might manifest as mass in a tangible way.
Or maybe it’s just the case that the amount of energy needed to create mass is astronomically minuscule.
🤔 I suppose that’s the principle behind atomic bombs 🤔
Or maybe it’s just the case that the amount of energy needed to create mass is astronomically minuscule.
It would actually be an astronomically large amount. An atomic bomb will turn a very tiny amount of mass into a tremendous amount of energy. And that’s with a nuclear process that is way more efficent then a chemical one like photosynthesis.
But from pure physics standpoint a carbon atom and an O2 molecule will have a teeny-tiny bit more mass than a CO2 molecule (which is why combining or burning them together will release some energy). So doing the reverse and splitting up a CO2 molecule into it’s parts will generate a little bit of mass.
Wow - that’s what I meant. Not sure how I managed to get it backwards.
And to think I fretted so much over using “astronomically” and “minuscule” together 🤪
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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.
What about all the mass and materials turned into satellites and rovers that have been sent off planet? Has Earth shrank?
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…
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.
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)
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.
You could pound it with astroids
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Happens all the time, for eons. See: “shooting stars”.
Not sure what “grow” means here exactly. But yes, the earth’s mass will increase.
I mean would Earth get bigger in size as a planet.
You would need massive amounts of material, but yes, it is possible.
You need any nonzero amount of material
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.
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
