an object will not continue accelerating like classical physics says.
as you approach c , time will slow down and hte time it takes to accelerate will increase and you will end up never making it to c.
where c is hte speed of light.


So really inertia is much more complex.

Light cant be slowed down, not even through water , its actually an effect of our vison , that makes an illusion that it slows down.

hah.....light can slow down! that why it bend near gravity.....another fact is

cherenkov(aka.cerenkov) radiation which is when particle emited(neutrinos etc.) are moving faster than the speed of light in that medium.....so they are moving faster than light in air...causing ionization of the air.. giving of a blue glow.....

i also saw on discovery some guy had this really dense dense liquid in a aquarium and put a laser beam perpendicular to the edge... and you could see it curve downwards.....and ingeniously he put mirrors where the laser would bend down so they would bounce back up etc..

light is not radiation is a wave and a particle part of the duality principle....it acts as a wave as it can change frequency but can be warped by gravitational fields...

C is actually the speed of light in perfect vacum which is impossile and is an estimate....

if any can add on please do.

14. The moon revolves round my head faster than light!

Stand up in a clear space and spin round. It is not too difficult to turn at one revolution each two seconds. Suppose the moon is on the horizon. How fast is it spinning round your head? It is about 385,000 km away so the answer is 1.21 million km/s, which is more than four times the speed of light! It sounds ridiculous to say that the moon is going round your head when really it is you who is turning, but according to general relativity all co-ordinate systems are equally valid including revolving ones. So isn't the moon going faster than the speed of light? This is quite difficult to account for.

What it comes down to, is the fact that velocities in different places cannot be directly compared in general relativity. Notice that the moon is not overtaking the light in its own locality. The velocity of the moon can only be compared to the velocity relative to other objects in its own local inertial frame. Indeed, the concept of velocity is not a very useful one in general relativity and this makes it difficult to define what "faster than light" means. Even the statement that "the speed of light is constant" is open to interpretation in general relativity. Einstein himself in his book "Relativity: the special and the general theory" said that the statement cannot claim unlimited validity (pg 76). When there is no absolute definition of time and distance it is not so clear how speeds should be determined.

Nevertheless, the modern interpretation is that the speed of light is constant in general relativity and this statement is a tautology given that standard units of distance and time are related by the speed of light. The moon is given to be moving slower than light because it remains within the future light cone propagating from its position at any instant.

Light, like all electomagnetic radiation, is carried by a particle called a photon. Sometimes it's easier to think of a photon like a wave, sometimes like a particle. Huzzah for quantum theory and particle/wave duality... such a wonderful source of confusion!

im 99.9% sure i know what im talking aboutthanks to university and reading, but i have not hunted down these articles you speak of.

In passing through materials, light is slowed to less than c by the ratio called the refractive index of the material. The speed of light in air is only slightly less than c. Denser media, such as water and glass, can slow light much more, to fractions such as 3/4 and 2/3 of c. This reduction in speed is also responsible for bending of light at an interface between two materials with different indices, a phenomenon known as refraction.

Since the speed of light in a material depends on the refractive index, and the refractive index depends on the frequency of the light, light at different frequencies travels at different speeds through the same material. This can cause distortion of electromagnetic waves that consist of multiple frequencies, called dispersion.

Note that the speed of light referred to is the observed or measured speed in some medium and not the true speed of light (as observed in vacuum). On the microscopic scale, considering electromagnetic radiation to be like a particle, refraction is caused by continual absorption and re-emission of the photons that compose the light by the atoms or molecules through which it is passing. In some sense, the light itself travels only through the vacuum existing between these atoms, and is impeded by the atoms. The process of absorption and re-emission itself takes time thereby creating the impression that the light itself has undergone delay (i.e. loss of speed) between entry and exit from the medium in question. It may be noted, that once the light has emerged from the medium it changes back to its original speed and this is without gaining any energy. This can mean only one thing - that the light's speed itself was never altered in the first place.

wtf kinda bull shit do your schools teach you?

http://www.rpi.edu/dept/phys/Dept2/APPhys1/optics/optics/node4.html

because the speed of light is different in two different mediums, it bends.

if light didnt change speeds in different mediums, then the general theory of relativity would not make sense.

light does have different speeds, end of story any one who says other wise without providing proof is an idiot

from the view of the person in the vacume..

you say general relativity staes that light changes speed, BIG BIG BIG NO NO , general relativity understands that light is constant in every inertial referance frame regarless of the observer , it only apears to be slower. light is not relative, this is part of General relativity , light is not relative to anythign , it just keeps chugging along at c, these observations all show that light can take longer paths , or get stuck in a path , thus creating hte illusion of faster and slower.

the person in the vacuum would be dead
[/derail]

"The Hitchhiker's Guide to the Galaxy says that if you hold a lungful of air you can survive in the total vacuum of space for about thirty seconds. However, it does go on to say that what with space being the mind-boggling size it is the chances of getting picked up by another ship within those thirty seconds are two to the power of two hundred and seventy-six thousand, seven hundred and nine to one against."

w.e who cares, we're prolly all wrong nyways