There is lot of garbage out there, right above your head

Hi,
no no, I do not speak about the stuff in your house, though who knows how it looks like. I mean a junk on the orbit of Earth.

Earth from space, surrounded by small white dots

Stuff above your head in low Earth orbit and geosynchronous orbit.


This stuff which is hundreds of kilometers above may not really concern you, if it falls down it should burn up in the atmosphere.

Actually it should concern you since your life almost completely depends on satellites above that are still working.

Those that are still working are at the same time endangered because of those that are not working. How bad is it?

Well on one side not so bad. No huge catastrophy happened, yet.

On the other side this is just a matter of time, the thing that should concern us most is ISS of course since there are some people there. When some things fly on those heights, they tend to do it very fast, even 17,500 miles per hours. Take for example a cat, not that there are any cats 400 kilometers above Earth, she usually weights about 4,5 kilograms. What is the momentum of the cat?

The momentum is about 126,708.75 kg*km/h. This is a lot, how much?

Yes, this is your cat which is just going to destroy something

The same momentum has a car (1,590 kilograms is regular midsize) driving at the speed of 80 kilometers per hour.

Now just imagine a car crashing into something at 80 km/h, it will do a great deal of damage and same damage can create a cat flying on orbit (or 353 cats at the speed of 80 km/h).

Luckily objects of the size of cat can be detected, but it is kind of expensive.

Just for you to know, there are 20,000 pieces of junk that is larger than softball.

Now the greatest risk is by the junk we cannot detect because it could destroy windows or so. Also the more stuff we put on the orbit, the more likely it is to collide with something.

By the way in 2007 China tried to get rid of one satellite using missile, what happened? They destroyed it adding 3,000 more pieces of debris on the orbit. WORTH A SHOT.

Right now there are only guidelines to dodge this debris but no real solution yet.

Dragallur

Check out this cool page that simulates what is flying above.

 

Debris disk: Ring around star

Hi,
with this post I am answering to one comment posted about three weeks ago on Roche limit.

Could there be rings around sun?

Yes they are called Debris disks. Debris disk is created from nebula which is surrounding young star. This nebula is full of gas and dust. Either all this stuff is pushed away by radiation or planetesimals are created.

Planetesimals are huge rocks, (more than one kilometer across). They do not need Brownian motion anymore to grow because they have enough strong gravity to pull other rocks, and at some point they can be enough large to be planets.

When those planetesimals collide they left dust and rock behind them. This is what isHeic0821f.jpg called debris disk. It is not created by Roche limit as normal planetary ring is and I did not find anything about rings around star that are made by Roche but if I do I will definitely post it here.

This dust in debris disk is usually very small: 1-100 micrometers.
Our sun has this debris disk and you have probably heard about it, it is the Kuiper belt.

There is other example of debris disk and it is around very bright star called Fomalhaut. Ring Around a StarYou can see it on the right top. This star has debris disk which is moved by 1.4 billion miles (roughly 2.24 billion kilometers) to left. It is probably because of huge planet. The dark spot around star (pic. on the left and bot.) is just effect of blocking the light from Fomalhaut so we can see all the debris reflecting photons. This false-color composite image reveals the orbital motion of the planet Fomalhaut b.
Fomalhaut has at least one planet and this one is called Fomalhaut B. On wiki, I am pretty sure there is mistake in one sentence since they are saying that it is star.
You can easily find Fomalhaut on Celestia, I will write about that program probably next time.

Dragallur
PS: I lost.