Hi ! Imagine for a second a spotlight. A big one. A really really big one. Now, make is 100 times bigger. Now super size it. Is it really huge yet ? Good. Now make it a million times bigger. And replace the light bulb with The Sun ! Wooohoo. That's one big spotlight ! Okay.. Now.. Imagine a dusty room. You know that room where you can see the sun beams in the air because of the dust ? Cool. Remove the walls, the celing, the floors. Now we have us some dust. Spread that dust all over our solar system. Don't be shy. Really spread it out. Now.. place the Sun Powered Spotlight on Pluto. Aim the spotlight somewhere far. Turn off the sun for a minute. Now... Turn on the spotlight ! ... ... ... If light moves at speed X. And we can see the light(because it's so really really bright)(and because it's going through thin dust, letting us see the beam itself). (here comes the big question) Will we see a huge beam racing through the sky ? If not, then what ? PS - If unclear, I'm a physics newbie, and pretty much don't know alot about it.