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