Subject: Can you see Cosmic Particles?

For as long as i can remember i have ocasionaly seen very small bright 
lights moving eraticly through the air like tiny flys for a distance of 
about 15 cm, after traveling that far they disapear as quickly as they 
appeared, this usually happens when i stand up and sit down quickly. Any 
way i recently saw a science show about space that told about how 
astronauts that went in to space could see similar lights as i described
they claimed they were cosmic particals.
Can you tell me what it is that i am actually seeing, are they real or is 
it in my head? oh and the harder you look for them the more you can see, 
if you look in to the sky on a cloudy day and just focus on movement in 
your periferal vision you can see thousands of them.

Regards Daniel

Re: Can you see Cosmic Particles?