How do you calculate lightyears distance?
914780
Well, we look at the light and determine "this light is about a million years old." :-) Not really, but that's the general idea.\n\nFor galaxies of very large distance, we can determine how fast the galaxy is receding from us. The easiest way is the Doppler shift - we can see the galaxy (obviously) and therefore astronomers can determine how big it is, what type of stars must be in them, and therefore what color light we should see. However, the light is slightly redder than what models predict (and what nearby galaxies have). We can measure this "red shift", plug it into Doppler's equation, and determine how fast the galaxy is moving. (This is similar to how when a police siren passes you, it drops its pitch - and how much it changes is proportional to how fast the police car is going.)\n\nThen there's a nice relationship called Hubble's Law, which states that the farther a galaxy is from us, the faster it's receding. This is a consequence of the Big Bang, and indeed the constant in this equation must be the reciprocal of the age of the universe. So we can then estimate (within a few thousand years or so) how far the galaxy must be from us.\n\nFor closer galaxies, there are some other techniques. There are certain types of variable stars (stars that, every few hours or days, increase and decrease their brightness) that in order to be stable must vary between two known brightnesses. Of course the brightness isn't exact, but the average among the thousands of variables in a galaxy is very close to exact. Now when we measure brightness (actually, apparent magnitude) from Earth, we see stars dimmer if they're farther from us. But because we know the absolute magnitude of these variables, and we can measure their apparent magnitude, we can calculate the distance we must be for them to become this much dimmer.\n\nThere are actually a lot of techniques, which work better for certain distance ranges. Look up the "distance ladder" if you're interested.
787354
Yes, we're seeing what happened to/on that planet 50,000 years ago. Light years are a measure of distance, not time; one light year is the distance that light travels in one year. Therefore, the light we're seeing from that certain planet left that planet 50,000 years ago. It's like looking back in time.
172339
Normally you'd describe shorter distances like that in AU (astronimical units - 1 AU=distance from earth to sun).\nBut - The distance is almost exactly 499 lightseconds - ie \nearth2sun in lightseconds/(days per year*seconds per day).\n499/(365.25*86400)=0.000016 lightyears.
2069
Use the aplet on the following website to convert to distance:\nhttp://jan.ucc.nau.edu/~cvm/latlongdist.html\n\nIf you prefer to use the pen and paper method:\nhttp://mathforum.org/library/drmath/view/51711.html
16422
A light year (or light-year), is defined as the distance that a photon would travel, in free space and infinitely distant from any gravitational or magnetic fields, in one Julian year (365.25 days of 86,400 seconds each). Since the speed of light in a vacuum is exactly 299,792,458 m/s by the definition of metre, one light year is exactly equal to 9,460,730,472,580,800 m, or about 5.879 × 10^12 (nearly six trillion) miles.
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.
344107
distance travlled by light in one year.\n\nso, mathematically, that is:\n\n299792458*365*24*3600\n\n= 9.45425496 × 10^15 metres
166283
A light-year is a unit of distance. It is the distance that light can travel in one year. Light moves at a velocity of about 300,000 kilometers (km) each second. So in one year, it can travel about 10 trillion km. More precisely, one light-year is equal to 9,500,000,000,000 kilometers.
221827
by using the speed of light. As the Sun emits the light, it takes time to reach Earth. The speed and time taken is calculated to get the distance between the two. It takes about 7 minutes for the light to reach Earth. So looking at the sun from Earth is looking at the Sun 7 minutes ago!
8760
None, the two are not related. Earth's rotation is a measure of time and light years are a measure of distance.
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!
825824
Neptune is what, 2 or 3 billion miles away?  A light year is 6 trillion miles, so the distance is less than .001 light years.  Light years are practical only when measuring interstellar distances.
765526
As you know, light year is not a measure of time but the naswer is:\n\n365x24=8760
362323
Given the latitudes and longitudes of two places on earth, the distance between them:\nD = R * arccos{cos(long1-long2) * cos(lat1) * cos(lat2) + sin(lat1) * sin(lat2)}. \nhttp://www.cs.cmu.edu/~mws/lld.html \n\nbut if tou don't want to make the calculation, in next pages they determine the distance between two points on the earth given their latitudes and longitudes:\nhttp://www.export911.com/convert/distaCaIc.htm\nhttp://jan.ucc.nau.edu/~cvm/latlongdist.html
591913
Despite it sounding like time, light year measures distance.\nIt's the distance that light travels in space in one year, a very long distance.\n\n186000*365*24*3600 = 5.87 x 10^12 miles.
537507
1 lightyear = 9.4605 × 10^15 meters\n70 miles/hr = 9.875*10^8 meters/year\n\n9.4605 × 10^15 meters/ 9.875*10^8 meters/year = 9.58*10^6 years
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.