how long does  it take for light to get from earth to mars?
141128
My calculation says it's about 4.35 minutes.
68058
Two of these answers were correct (the speed of light in a vacuum is exactly 299792458 meters per second), although the appropriate reference is not wikipedia but the Bureau International des Poids et Mesures (BPIM).  This is the internationally recognized "official" source.\nhttp://www.bipm.fr/en/si/base_units/\n\nThe speed of light in a vacuum is exactly known because the meter is defined (by the BPIM) as being the distance that light in a vacuum travels in 1/299792458 of a second\n\nThe answer from Trsmd is not quite correct in stating that the speed of anything can be measured by determining the distance in travels in a given amount of time.  Since our units of distance are defined in terms of the speed of light, the correct statement would be that distance can be determined by measuring the amount of time that it takes light to travel that distance.\n\nAlso notice the qualifier "in a vacuum".  The speed of light travels more slowly when it travels through something like air, water, or glass.  How much more slowly depends on the properties of the material (density, composition, temperature, etc.)
1098746
hold on here, this isnt a short answer - \n    the Earth is on average 92Million miles from the sun, times pi for the circumforance and its roughly 290Million miles around.  divided by 365 for the number of days, the earth travels some 790,000 miles on one day, ya thats high on the odometer.  distance in one day divided by 24 hours comes to 33,000 MPH, now i did this on my computer but it does seem right, \n\nNow part 2, hang on here, big numbers ahead, the Solar System wihich Earth belongs to is roughly 26,000 Lightyears from the galactic core, (which has a Supermassive Black hole as heavy as 6 Trillion suns).  it take a quarter of a Billion years (250,000,000) for our solor system to complete one revolution around the galaxy. The circumferance could be some 80,000 Lightyears,  though i am not sure how to calculate the speed of the solar system.
327223
1 lightyear is the distance a beam of light can travel in a vacuum in one year.  Given that the speed of light is roughly 3*(10^8) meters per second, or about 670.6 million miles per hour, then 93 million miles is about 1.58*(10^-5) lightyears.  Another way to look at it, is that it takes about 7.21 minutes for light from the sun to reach earth, and they are roughly 93 million miles apart.
259168
Light travels at 670,616,629.4 miles per hour, so you multiply that by the number of hours in 35 years.\n\n35 years x 365 days/year x 24 hours/day x speed of light in miles/hour.\n\nIt's like 205,611,058,574,040 miles.
533977
12 hours light distance means: the distance light travels in it for 12 hours.\n\nKnowing that the speed of light is in vacuum 299,792,458 metres per second or 1,079,252,848.8  kilometres per hour, or 186,282 39937/100584 miles per second, or 670,616,629 537/1397 miles per hour. The speed of light through a transparent medium (that is, not in vacuum) is slightly less; the ratio of c to this speed is called the refractive index of the medium.\n\nIf you multiply 1,079,252,848.8  kilometres per hour by 12, you get 1,295,103,418.56 km, a very long distance. If you want to use multiple mirrors to get the "infinite-effect" to "create" this immense distance you need to get a reflection of the sun (with a concave mirror) exactly between the two facing mirrors. Even if you make this happen, remember that the mirror has no memory: when the reflected object is removed from before the mirror, the reflection stops also.\n\nWhy don't you just use regular solar cells that turn solar heat/light into electricity and use a lightbulb after dark?
585240
um depends how fast you're going. If you're going the speed of light it would only take 8 minutes. \nIf you were flying in the spaceshuttle, which goes Mach 25 or about 17,500MPH it would still take 221 days to get to the sun. So not even a year.
664924
The average distance from Mars to the Sun is 1.52369 astronomical units.  One astronomical unit (AU, the average distance from the Sun to the Earth) is 1.49597870E11 meters.\n\nConverting those numbers, then, means that Mars is:\n\n1.52369 * 1.4959787E11 meters = 2.27941E11 meters, or, converting into English units:\n\n141,635,833 miles (on average -- remember that the orbits of the planets around the sun are not circular, but elliptical)
270456
On average, 2,432,890.5 miles per day. (Mars orbital circumference of 888,005,041 miles divided by 365 days.)
123056
The Earth would immediately leave it’s orbit in a direction tangential to the current orbital plane at a velocity equal to it’s current orbital velocity, roughly 11 km/s.  The final path will be modified by the gravitaitonal force of the other solar system bodies, but since the Sun’s gravitational attraction is much greater than the others,  the solar system would just fly apart.  \n\nThere’s no delay in gravity force propagation, so the effects will be instantaneous the moment the gravity is “turned off”.\n\nEDIT:  \n\nmrjeffrey 321:  It is correct.  The information of the sun's gravitational field really does travel faster than the speed of light.  I don't have any vested interest in any particular theory, I prefer to look at the facts and the experimental data.  Ask any astronomer who performs astrometric or planetary position calculations using celestial mechanics.  The positions of the planets are always calculated using instantaneous gravity.  The positions are then corrected for aberration, the visual position error caused by the fact that light is speed limited.  So, we really calculate the actual positions of the planets, and then we correct for where we actually see the light coming from these planets, delayed by the speed of light.\n\nIn fact, if you model the solar system by adding in a delay for "gravity propagation" at the speed of light, the orbits of the planets in the solar system begin to slowly deteriorate.  This is most obvious with observations of certain binary double stars, where any delay in gravity would cause the star pairs to fly apart.  According to actual ephemeris measurements, the Earth is being accelerated to point about 20 arc-seconds ahead of where the sun appears in the sky.  This is because gravity is pulling us instantaneously towards the true position of the sun, not the apparent position we see in the sky.\n\nI'm not an expert on relativity, so I'm not going to argue fine points about what general  or special relativity either does or doesn't say or is interpreted to say.  What matters is the actual evidence, and the evidence says that the effects of gravity are instantaneous.\n\nNote that there was a paper published back in 2003 regarding the measurement of the speed of gravity, which resulted in it being very close to the speed of light.  There are several errors in this paper that were pointed out after publication.  The calculations used were shown to be incorrect.\n\nAn interesting question on this subject is black holes.  If we agree that gravity is a particle or wave, and we agree that nothing, no information, can escape a black hole, then how is it that black holes exhibit gravity? If they are truly so massive that they warp the very fabric of space-time, then how is it that gravity waves can escape when light cannot  If we accept the fact that black holes are "information holes" in the sky, how can they reveal themselves through gravity?
71870
Yes,\n\nIt takes light sometime to get from the sun to the earth.  But if you look at the sun, you see it instantly, so I guess it would be the speed of sight if there is such thing.
1178302
Mean distance from earth149.6×10^6 km or (92.95×10^6 mi)\nIt would take about 8.31 minutes at the speed of light to go from earth to sun.
309054
given the figures, another way to "imagine" how far it is\n IS that Light (at 186,000miles/sec)takes about 8.3 minutes to get to earth from the sun and takes 5.5 hours to get to pluto\n\nPluto is 40 times the distance away from the sun as the earth \n\nOver 11,000 earths will fit between the sun and earth if lined up so about 460,000 earths fit between the sun and pluto.\n\nAlso if the Sun was a beach ball, the earth would be a pea and Pluto would be A LARGE grain of sand.\n\n\n\nThe numbers are often useless unless we "translate them" into "concrete" terms because we have peas er I mean grains of sand for brains ;)))).
220002
its done by counting how long it takes for light from the planet takes reach here. usually between a period of dark and light. same as the sun
956950
The exact same as all light -- all wavelengths travel the same\n\n3 x 10 ^ 8 m/s or 186,000 miles per second
6671
The exact speed of light is 299,792,458 m/s\n\nTo be precise, what we usually call the "speed of light" is really the speed of light in a vacuum (the absence of matter). In reality, the speed of light depends on the material that light moves through. Thus, for example, light moves slower in glass than in air, and in both cases the speed is less than in a vacuum. However, the density of matter between the stars is sufficiently low that the actual speed of light through most of interstellar space is essentially the speed it would have through a vacuum, so we don't make much error by ignoring the difference.\n\nTo make it easier for you to convert, here is the speed in alternative units :\n\n(1) 983,571,056.4304461 foot/second\n(2) 11,802,852,677.165352 inch/second\n(3) 1,079,252,848.8 kilometer/hour\n(4) 299,792.458 kilometer/second\n(5) 582,749,918.3585312 knot\n(6) 880,991.0899527 mach\n(7) 670,616,629.3843952 mile/hour (mph)
966288
I remember this from college as being quite a long time, but I can't remember it exactly. This is from Wikipedia:\n\n"The high-energy photons (gamma and X-rays) released in fusion reactions take a long time to reach the Sun's surface, slowed down by the indirect path taken, as well as by constant absorption and reemission at lower energies in the solar mantle. Estimates of the "photon travel time" range from as much as 50 million years to as little as 17,000 years."