[ovrdrv3]

As a naive bystander, can you please explain why it would be bad to "pollute" space? Do things fall back into the atmosphere and burn up and sprinkle ash back onto the earth? I thought that objects once past the gravitational pull of the earth will just continue to drift away into the nothingness of space, and no matter the volume, it would be an insignificant amount to cause any harm to our planet or view of the stars.

[JumpCrisscross]

> can you please explain why it would be bad to "pollute" space? Do things fall back into the atmosphere and burn up and sprinkle ash back onto the earth?

The risk of space junk falling on people is tiny. The chief concern is around collisions in orbit. Worst case: "collisions between objects could cause a cascade where each collision generates space debris that increases the likelihood of further collisions," which could create a "distribution of debris in orbit [that] could render space activities and the use of satellites in specific orbital ranges unfeasible for many generations" [1].

These regulations are about protecting affordable access to space, by managing the risk of collisions.

(Eventually, yes, most things will fall down or burn up or drift away. But that process can take years if not millennia.)

[1] https://en.wikipedia.org/wiki/Kessler_syndrome

[baobrien]

Things don't really leave the gravitational pull of the earth -- it's still on the order of 9m/s^2 in low earth orbit. In order for things to stay up, they've got to be moving around 9 km/s sideways -- essentially constantly falling towards earth, but going fast enough sideways to miss.

The issue is that at those speeds, anything bigger than a fleck of paint hitting anything else will turn both things into a bunch of tiny chunks. See [1] for an example of two satellites colliding.

The big fear is that if you get enough stuff up there, even if you control most of it, one collision would be enough to trigger a chain reaction. [2]

[1] - https://en.wikipedia.org/wiki/2009_satellite_collision [2] - https://en.wikipedia.org/wiki/Kessler_syndrome

[ovrdrv3]

Thanks for the reply, I definitely didn't think of this point.

[evgen]

Where do you think the "gravitational pull of the earth" ends? Hint: the moon is inside the gravitational pull of the earth... The danger is that things in orbit have velocity. A lot of velocity. Taking that nice F=mv^2 equation in mind you can imagine what would happen if a piece of space junk were to hit something we care about (or hit something we don't care about and create a lot more little pieces of junk that are now spreading out to cause more mayhem.) Space is big, and earth orbit is also a very big place, but there is still a lot of junk whizzing around up there and increasing the odds that something you forgot about will hit something you care about is counter-productive.

[greenhouse_gas]

Just to emphasize: There is no limit to the earth's gravitational pull. The formula is F=G*sqrt(m1m2)/r^2.

So as r (the distance between the center of the earth and your satellite) increases, F decreases. But it never hits zero.

Though after a while (a Sun-Earth L point, is it?), the influence of the sun will be greater (by orders of magnitude) than the earths.

[liuhenry]

For most interplanetary missions, Earth's gravitational pull on spacecraft can be modeled as a sphere of influence of about 1 million km.

https://en.wikipedia.org/wiki/Sphere_of_influence_(astrodyna...

[tajen]

I wonder as well what is the zone he’s talking about, but he talked about the zone in 9m/s2, not F=mv^2. I guess the first one extends up to 100km altitude, where I think geostationary satellites are, and indeed is very closeby.

Edit : Low earth orbit is 180+km, for weather satellites because they revolve in 99 minutes. Geostationary orbit seems to be around 36000km with a speed of 3000m/s. https://earthobservatory.nasa.gov/Features/OrbitsCatalog/

[shostack]

One of my favorite "slice of life" anime series out there is PlanetES[1]

It does a great job of illustrating the potential impact of this on humanity in the not too distant future, and some of the jobs it creates (space trash collectors).

[1] https://en.wikipedia.org/wiki/Planetes

[dtech]

Objects can stay in orbit for a long time and become dangerous for other objects there. Look up Kessler Syndrome.

[valuearb]

Swarm's Spacebees have a max orbital altitude of 360 miles, they are unlikely to remaining in orbit for more than 5 years.

[awat]

I’am positive someone expressed that exact sentiment about the ocean at some point. I had a Botany professor who always used to say “there is no such place as away”.

[andrewaylett]

Generally, because the debris might hit other stuff and break it.

Space is big, but too much stuff goes into very similar orbits.