well never be able to make the jump to lightspeed

Well never be able to make the jump to lightspeed how to#

Taking the limit as the distance approaches zero yields a speed equal to 'c' however, even for a vertical beam of light. Gravitational fields will have only a second order effect on speed measurements - thus if the beam of light was vertical, one might see such a second order effects on the speed measurement if the vertical distance were long enough. Neither does the motion of the sun around the galaxy, or the motion of the galaxy relative to whatever else you might chose as a reference. The motion of the Earth around the sun does not affect the measurement of the speed of light at all (except insofar as it affects the rotation of the Earth, by making the sidereal day a bit shorter than the solar day). This care would not be needed if the Earth were not rotating. The sagnac effect is well enough understood by physicists that they don't actually use gyrostabalized non-rotating platforms when they make their speed measurements, rather they just design their experiment so that the sagnac effect does not affect their results (by insuring that the area of the path over which the speed is being measured is zero).

Well never be able to make the jump to lightspeed how to#

It would be the least confusing to say that the speed should be measured in a non-rotating frame, but if you want the gory details of how to deal with rotation in special relativity you could read about the 'sagnac effect', the effect that makes laser gyroscopes possible. The trickiest points arise with respect to rotation. None of these matters when the speed of light is measured over short distances. Thanks for your replies wildman and pervect.ĭoes the fact that we are spinning on an axis, orbitting the sun, orbitting the black hole in the center of the milky way and the universe is expanding not effect our measurements of light? Some of the experimental tests of relativity are discussed at The Earth is constantly changing it's speed due to the fact that it is orbiting the sun, but we've never seen any indication that this affects measurements of the speed of light. The lack of dependence on the speed of light shows up in experiments like the Michelson Morley experiment. See for instance for details of this and other experiments. The speed of light from pi0 mesons has been measured to be equal to 'c' within 400 parts per million, in spite of the large velocity (.99975 c) of the mesons. There are both cosmological sources that move with high velocities to us, and terrestrial sources that move with a high velocity and emit electromagnetic radiation, such as pi mesons (which move at a high fraction of 'c'). The independence of the speed of light from motion of the source has been measured in a number of ways, one of the most direct was to measure the speed of light emitted from a moving source. And in special relativity, the speed of light is always equal to 'c'. This means that over small distances, well away from strong gravity fields, one can use special relativity. In a small area of space-time, curvature effects can be ignored, similar to the way that the Earth is a round ball, but appears flat from the perspective of someone who does not travel a great distance over its surface. However, it is necessary to understand SR well before one can move on to GR. Curvature effects are more complicated to talk about and describe, and are dealt with in General relativity. Some other ratios of distance to time in cosmological situation might not be equal to c, but these discrepancies can usually be attributed to the curvature of space-time. It is important how you measure and define the speed of light - the speed of light is equal to 'c' only when you measure it over short distances using local clocks and rulers. The speed of light is always 'c' (using local clocks and rulers), and this fact has nothing at all to do to do with universal expansion as other posters have already remarked.