time taken by light to reach on earth from alpha centuri?
488135
A little over 4.35 light years.
1072544
there is no exact figure as earth follows an elliptical path and it is at different distances from sun at different times.\nbut on an average 8* 60*c meters    where c is speed of light
281399
1) Light is both a wave and a particle phenomenon. Experiments can be devised to demonstrate either the particle or wave properties of light, just not at the same time (see 'particle wave duality').\n2) About 1,000 seconds. An astronomer named Christian Huygens (I think... might've been Oersted) first observed a 1,000 second discrepancy in the observation of Jupiter's moons eclipsing when observed in the summer as opposed to in the winter. This led him to the first good approximation for the speed of light, i.e. the extra time it took the light to cross the diameter of Earth's orbit could be measured, and since the approximate diameter of Earth's orbit was already known: Speed = Distance/Time or 186,000,000 miles divided by 1,000 seconds = 186,000 miles per second.\n3) The light year is a unit of DISTANCE, not TIME!! It is the distance that light travels in one year, or about six TRILLION miles. However even at this staggering speed it takes light over four years to reach the nearest star to Earth (other than the sun).
587733
Light travels at 186,282 miles per second.  So multiply by 60 (seconds per minute) by 60 (minutes per hour) by 24 (hours per day) by 365 (days per year), which gives 5,874,589,152,000 miles for 1 light year.\n4.2 light years works out to 24,673,274,438,400 miles.  Quite a long walk :) \nHere's a way of illustrating this:\nIt takes light 1.27 seconds to travel the 238,000 miles from the Earth to the Moon.  If this distance is represented by 1.27 inches, then an object one light year away would be 636 miles away, and a star 4.2 light years distant would be 2,670 miles away - about 200 miles more than from New York to Los Angeles!
171383
It takes anywear from 8-9 min! The reason being that the earth does not revolve around the sun in a perfect circle. This answer only counts if I interpreted your question correctly.If not the speed of light itself does not travel.
687280
Not counting the sun, the closest star to earth is Proxima Centauri, which is about 4.1 light years away from the earth. Light travels at 300 000 km/s so you can now use this to calculate the distant. 4.1 light years x 365 days per one light year x 12 months per 1 year x 30 days per one month, x 24 hours per one day x 60 minutes per one hour x 60 seconds per one minute = 4,654,713,600 seconds. Multiply this figure by 300 000 km/s and you get an answer of 1,396,414,080,000,000 Kilometers.
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.
75221
I'm not a physisist nor an astronomist, just crunching some numbers.\n\nAllowing that the speed of light is 186,000 mps, then:\n\nMercury (36) = 3 1/2 minutes\nVenus (67.2) = 6 minutes\nEarth (93)   = 8 1/2 minutes\nMars (141.7) = 13 minutes\nJupiter (484) = 43 minutes\nSaturn (887)  = 1 hour, 19 minutes\nUranus (1785) = 2 hours\nNeptune (2795)= 4 hours, 10 minutes\nPluto (3675)  = 6 1/2 hours\n\n*number in () is the distance in millions of miles from the sun\n*all times were rounded
1017333
No, because the speed of light is constant and the distance to stars can be accurately calculated by measuring the time it takes their light to reach us.
402996
Light travels at 186,000 miles per second, or 300,000 kilometers per second.
194179
The distance from the earth to the sun is about 93 million miles. The speed of light is about 186,000 miles per second. Dividing shows that it tkes light about 500 seconds to go from the sun to the earth. That's 8 minutes 20 seconds.
626653
Proxima Centuri. About 4.2 light years away. Check the foll link for more info\n\nst
917979
Albert said it, you can't get there from here. Let's assume you have the infinite power source you will need to push the near infinite relativistic mass you have as you approach the speed of light and you are deep space with no air friction or other forces to worry about, in other words, the ideal (but impossible) case.\n\nVelocity is acceleration times time. Light travels at 186000 miles per second.  One Gravity is 32 feet per second squared. So, we work backwards from the desired velocity and doing unit conversion from miles to feet . 186000=96/5280*T\nThe answer is 186000*5280/96 which is 10,230,000 seconds, which at 86400 seconds per day means 118.4 days.\n\nWhich does not sound nearly long enough...
1071620
Because the light has taken that long to get here.\n\nWhen we look at a star 100 light years away, we see it not as it is but as it was 100 years ago. That star might have exploded 80 years ago, but we won't see that for another 20 years.\n\nThe effect is even measurable with the Sun. The light from there takes about 8 minutes to get here, so we see the sun as it was 8 minutes ago.\n\nYou seem to know what a light year is, but anyway, check the link.
360465
A light year is measured by the time on Earth not by your watch.  However, since one light year is the measurement of the distance that light travels in one Earth year, then one light year always equates to one year on Earth.  So, if you travel one light year, you should be one year older and the Earth would also be one year older (assuming no time anomalies, like a black hole, are encountered during the trip).  Keep in mind that a 'light year' actually measures distance (based on the speed of light).  \n\nHowever, time is always relative to where you are.  So, for you, time progresses at the same rate it always has (for the human body) no matter what's going on around you.  So, if you were gone for 3 minutes (clock time), you'd be three minutes older.  If you were gone for 24 hours, then you'd be 24 hours older.\n\nHowever, if you were to visit the proximity of a black hole, the theory is that time slows down.  So, while your watch may continue at the same rate as it always has (your time has actually slowed down).  So, time on Earth would be progressing at a much faster rate relative to you (even though Earth's progression is normal to them).  So, if you returned to Earth and your watch was only 12 hours later than when you left, time may have progressed days or weeks on Earth.  In which case, your body would have aged 12 hours instead of the days or weeks that it would have progressed if on Earth.
200970
The sun is 93 million miles from Earth on the average, since the Earth does have a slightly elliptical orbit. How long it takes to get there is kind of an incomplete question because it all depends what you want to do when you get there.\n\nIt wouldn't take long for a spacecraft to fly straight to the sun and either fall into it or zoom by and then off into space, but if you wan to launch a probe to study the sun you have to be more clever.  \n\nThe link below is information on the Ulysses probe sent out in 1990. Ulysses actually did something of a "bank shot" off of Jupiter in order to get into an orbit where it goes around the sun over its poles rather than around the middle, which is rather cool that it worked so well.  Imagine playing billiards on a table three miles long and two wide and sinking the eight in a corner pocket after banking off of two cushions -- and then multiply that by a million, and you have a good idea how difficult this stuff is.
1054714
if we travel at the speed of light, it would take approximately 4.2 years to travel to Proxima Centauri.  Obviuosly, we can't reach that speed.  Space Shuttles can reach a speed of 17,500 mph or 7823.2 m/s.  With this speed, it would take 161059.4 yrs