A light-year is the distance travelled by light in a year. It is simply used as a convenience, since the official SI unit - meters - results in very large numbers (for example, approximately 4 x 1016 meters to the nearest star).
Distances between planets in our Solar System are NOT usually measured in light-years, since a light-year is much more than those distances. Instead, the distances are expressed either in millions or billions of kilometers, or in astronomical units. One astronomical unit (AU) is the average distance from Earth to Sun (150 million kilometers).
It's really not so mysterious. Forget about light for a second ... just think about cars.
Imagine that every car in the world traveled at the same speed ... 5,280 feet per minute, let's say.
Never faster, never slower. Just a law of nature ... cars travel at 5,280 feet per minute.
Now let's say your grandmother lives 316,800 feet away from you. That's a big number, because
she lives so far away. In order to describe the distance to grandma's house, you want to invent a
bigger unit, so you don't have to say "three hundred sixteen thousand eight hundred feet" every time
you talk about the trip. You could invent a unit that's 5,280 feet long, and give it a name like "one mile".
Then the trip to visit her is easier to say ... it's still the same distance, but you only have to say "sixty miles".
Or you could make the numbers even more convenient. Invent a really big unit, to talk about
really long distances. How about the distance a car travels in one hour. That right there is
316,800 feet .. perfect ! Now, when you're planning a trip to visit grandma, you're talking about
a distance of . . . . . one car-hour ! That's a distance. It's the distance a car goes in one hour.
That explanation ran longer than I meant it to, but I think the details of the analogy are OK.
A "light-year" is a distance. It's the distance light travels in one year. It's a gigantic distance,
but you really need it in order to talk about the distances between stars.
The nearest star to us ... past the sun, that is ... is about 25,866,280,000,000 miles away.
I'm not even sure how to say that number, and even if I knew how, you'd be tired of listening
before I got to the end of it. So we don't use miles to talk about the distance to stars. We use
the distance light can travel in a year. That nearest star past the sun is ... 4.4 light years away.
Lightyears are not the speed of light. Lightyears are there to measure distance. One lightyear is the distance that light travels in one year.
When scientists refer to the speed of light, they're talking about the photons which make up light. Darkness is the absence of light; hence, there are no photons. There is nothing to measure. The speed of darkness is undefined as there is no quanta making up darkness. Put simply: There is no speed of darkness!
Yes. Other units such as miles, kilometers or astronomical units are too tiny to be practical in discussing the distances between the stars, or between the galaxies. One even larger unit is often used in astronomical measurements, the "parsec". This is the distance of one "parallax second of arc", and is approximately equal to 3.26 light years. For long distances across the galaxy, some astronomers use "kiloparsecs" as a unit of measure, and for intergalactic distances some astronomers use "megaparsecs" or "Mpc".
A lightyear is the distance light travels in a year, which is equal to just under 10 trillion kilometres. They use it just because its a lot easier to use. Its like trying to measure the distance from Canada to Mexico in centimetres. It's easier to use km, just like in space, where everything is so far apart, its easier to use lightyears.
Light Years isn't a time, it's a distance or a length. 1 Light year is the distance that light travels in one year. That is = 9,460,730,472,580,800 metres (in one year) = 9,460,730,472,580.8 kilometres (in one year)
Warp speed is faster than the speed of Light. Warp 1 is the speed of light and warp 2 is 10X the warp 3 is 27X and it increases by a power of 3 for every level. At warp 5 for example you could make to the closest star Proxima Centauri 4.22 lights years away. It would take hours instead of years to get there, but the power needed to generate that kind of speed would be enormous. Warp is so fast that objects come to you through a distress in space. For generating this we would have to concentrate energy so vast to distort space time. Also known as wormhole movement explained by Einstein's law of relativity.
The velocity of light in vacuum is 299,792,458km/s, for daily calculation it's considered as 300000km/s, so put the distance and "C"(velocity of light) in speed and distance equation and you will get the answer.[time=distance/speed]"atul ashish"
Distance at galactic scales is usually measured in terms of lightyears. Distance at cosmological scales may also be put in terms of Hubble red-shift factors.
A light year is the distance traveled by light in one year. Multiply light years by 9,460,730,472,580,800 (approximately 9.5 trillion or 9.46 x 10**12) to get kilometers. Other values sometimes seen are the result of rounding errors in the speed of light, or in how to define a "year". Scientists tend to use "parsecs" rather than light-years; light years are used more in popular science publications.
Ok well it's actually pretty easy so speed=how fast u go and distance= how far you go so put them together speed+distance= VELOCITY
An object such as a train simply CANNOT travel at the speed of light. You can investigate what happens when it moves close to the speed of light.
Ok well it's actually pretty easy so speed=how fast u go and distance= how far you go so put them together speed+distance= VELOCITY
The speed of light is 299,792,458 metres per second or "c". so d * 1,000 / c gives 1.2808861255609038703702145835837 seconds But classroom maths will put the speed of light at 300,000,000 meters per second. so d * 1,000/ c gives 1.28 seconds.
To put it simply, a laser distance measuring device consists of 2 basic parts; an (laser) emitter and a receiver. The emitter part knows when it is transmitting pulses of laser light and is synchronized with the receiver. The laser light beam is travelling at the speed of light, so the distance travelled is calculated based on the AMOUNT TIME IT TAKES TO REACH THE RECEIVER, that its round trip time divided by 2.
"An indistinct light in the distance" as in extremely hard to see.
time, distance
At a distance of about 12.88 billion light years, it is unlikely that it will still be there when you reach it. At a speed of "c" (Speed of light) you would still be unlikely to be able to reach it, as most further galaxies are receding at close, if not faster, than the speed of light. If however, the Universe was static, it would take about 12.88 billion years to reach it at the speed of light. As this is not possible, lets put this into perspective. The fasted man made craft is Voyager 1, so far travelling at 35,700 mph. At that speed, it would take a mere 241,900,000,000,000 years to reach IOK-1.
180,000 light years is a unit of measurement used to describe distance in space. It is the distance that light travels in vacuum in one year, which is approximately 5.88 trillion miles or 9.46 trillion kilometers.