why do you see stars when you hit your head on something hard?
347276
what r u people talking about. you can still see stars when you get hit, I have a personal experience although it was more like little squares of light.
1166968
There are many differences.\n\nBy the wording of your question, it sounds like you are speaking about the movement of celestial bodies.\n\nMost stars (except the sun, seem to stay in the same position in relation to one another.  The sun, moon and   the planets, change their position against the background of the "fixed" stars.  \n\nThis is because the objects in our solar system are close to us, so their change in position is much easier to see.  The fixed stars are so much further away, that their motion is harder to detect.\n\nThis is similar to the experience of riding in a car.  If you look at a distant mountain,  the appearance of it doesn't change very quickly.  But as you come close to a street or a building, the appearance changes dramatically. \n\nThe reason is that if you measure apparent motion by an angle,  an object twice as far from you must move twice the distance across your Field of vision to have the same apparent motion.
504075
My guess it's a response to stress.  Sight is the main sense in people lucky enough to have it and we rely too much on it.  If shocked, it might be good to have a clear sight in case something comes your way (imagine you're a caveman and big sabertooth cat is cominagetcha)
456370
Hmmm, could be different things.  \n\nGenerally flashes can be one whole thing.  One way this happens is when blood is rushing out of the head to other parts of the body(Like when someone is about to faint).  Standing up really fast after sitting a long while you can see dots of light floating around like a cartoon character would see stars after getting hit on the head with a mallet.\n\n"Floaters" can be a whole other.  Whenever you stare at bright light, temporarily part of your vision will "turn off" to protect itself.  Then you'll have a little black spot(or a while spot in the dark) floating around like bug.  Sometimes they can be permanent(in extreme cases, like staring at a solar eclipse), but usually for other medical reasons.\n\nThose are just examples, but there are lots of reasons why you can see odd things in your vision.  For example, I have strabismus(crossed eyes).  When an eye tries to jerk to one side really fast I sometimes see a black splotch in my vision for a second.  I've been told that's because the fast jerk is pulling the optic nerve on the back of my eye.  And the splotch is the back of the nerve on the retina(the "movie screen" part of your eye).\n\nWell, these are just examples.  But yea, go see a doctor.  I bet insurance would cover it and you won't lose anything.  Even if you've had this problem for years, it could get worse.  You never know.\n\n(Just if anyone was curious: I did have crossed eyes, but I had surgery to correct it cosmetically.  However, crossed eyes are not caused by the eye muscles being defective but by a lack of control of them.  It is more of a palsy because eye training can't completely "fix" the problem.  Cutting the muscle to weaken them does mask the "jerky" control, thereby giving cosmetically straight eyes.)
886314
Well, blunt trauma contusions can be quite serious. How long ago did this happen? Do you have black eyes? Bloody nose? If any of these symptoms are present or this has going on for more than 5 days seek medical attention immediately.  \nDoes it hurt when this happens? If you were hit hard enough you may have suffered some sort of C-spine injury or inflamed disk. Give it a few more days then go see a doctor or ER. If you have any other questions my sn is Horseybabe1990 (yahoo). IM me if needed
515094
The basic mechanism of a concussion is the brain banging up against the inside of the skull. Think of coffee in a cup in your lap in the car. You hit the brakes hard and the coffee tries to keep going, sloshing out of your cup. When the head under goes a rapid change in direction, the brain continues to travel in the direction it was already going. If it is a sudden stop, it continues to move forward in the cerebral spinal fluid that surrounds it, striking the inside of the skull. \nOversimplifying slightly, this kills a bunch of brain cells. The death of brain cells (and other interruptions in brain function caused by the same basic mechanism) causes the symptoms of loss of consciousness, dizziness, memory loss, "stars in front of the eyes."
763492
Actually the bump on the head is due to edema or a fluid accumulating in the area that you got hit thats why its a big buldge this fluid contains all kinds of cells neutrophils and macrophages. The bump will cause a break in the continuity of your blood vessles, and you get some blood leaking and slowly itll be engulfed. Since the head as well as most of hte body is rich in blood vessels its not a worry if a few vessles break when getting injured. Slowly the injured tissues (site of the bump) will start being selectively removed and newer tissues will form, this is why you see the different color changes every few days 2-3 days about, from red to blue to green to brown then faint and finally back to normal. Bruising in the head might be more severe though because it doesnt have fascia or fat protecting it under the skin layer, good luck hope this helps you.
322469
Light triggers a reaction to you brain thinking that there is dust in the air.
641107
One of the effects of "shooting stars" is the ionization of air around them as they flame  up and burn out. This ionization, the same which causes LOS (loss of signal with returning spacecraft) produces a radio burst. A simple experiment is to connect an antenna to your tv and tune to a low channel, like 2 or 3 where there are no stations. Turn the brightnest down so the raster JUST disappears.  Now when a meteorite flies thru the air, you will see the screen lighten a little. So if they burn up in the air, the only effect is radio noise.
264522
The healthy human eye is only restricted by external factors (ie.: poor visibility due to haze, dust or fog), just think how far the stars are!
1154123
it means that somebody rams there head hard and fast into your face. Normally they will try to ensure that there forhead conects with the bridge of your nose - breaking it nicely, before the move on to kicking the shite out of you
183418
It is my understanding that it is broken blood capilaries caused by the impacts. See a doctor. It could be something serious, and also try extra vitamin C. It helped me stop bruising so easily.
527159
It's due to the way in which your eyes percieve light. Focus is determined by a point of reference. If your friend that you are looking at is the point of reference, they will appear as if they are not moving.\n\nThis is similar to when it looks, in a car, as if you are going backwards when the truck next to you starts moving forward.
312576
Stars are big fiery balls of gas. Essentially the gases cluster together and become stars through gravity and fusion. It's a rather complicated process; check the link below for a more detailed explanation.\n\nStars appear to be in our sky because they are in space. Most stars appear to be small points of light, although many of these stars are smaller than our sun. The sun simply appears larger because it is much nearer to the Earth.
139438
Swings mess with your inner ear which is responsible for your balance.  The same kind of thing happens on the seashore when the tide is going out.  I was once standing there looking down and I ended up on my butt.  It is one of those times when your senses play tricks on your brain.
1048072
There's a relative way to interpret your question as well.  \nWhen you look at the stars, you're seeing them because of the light that travels from them to you.  It takes time for the light to reach you.  So, you're not seeing the stars as they are "now".  You're seeing them as they were in the past.  They may not even be there any longer.  They may have gone nova or even supernova (if big enough), but the information of that event traveling at the speed of light hasn't reached us yet.  Just  remember it's all relative.  So, depeneding on which oberserver you ask and how you define certain terms...just how many stars that you can see are really there?
231023
This is caused by thermic convection of the air. In the deserts you normally have high differences in temperature between day and night, so hot air is rising rapidly while cold air is moving downwards after sunset. This different densities in the air makes the light bend and the stars seems as if they are dancing, just as if you were looking through an irregular glass. \nIt's a bad night for astronomers.