# What is a light year and how many earth years are equivalent to a light year?

A light year is a unit of distance light travels within a year. light travels at 300,000 kilometres per second. So one light year equals approx. 9,500,000,000,000 kilometres.

so what you are trying to say is that a lightyear canot be quivolent to an earth year?

You are correct - that is exactly what she is saying. A “light year” is a measure of DISTANCE, but a year is a measure of TIME.
The question “ how many earth years are equivalent to a light year ? “, is just as nonsensical as asking “ how many inches are equivalent to one hour ? “, or “ how many metres are there in one second ? “

No, it’s not a lightyear is a distance of light not years. An example is, that the sun is around 8 light minutes away. If the sun suddenly explode right now, we wouldn’t know about it for eight minutes because that is how long it would take for the light of the explosion to get here. They use lightyears purely because how large the numbers are so they work in ‘lightyears’ instead of saying it in miles/kilometres.

Thanks for clearing that up too majikthise.

Oh ok i see now, thanks guys, so lets say if you want to travel 600 lightyears how much time will it take you to get there?

Correct, an earth year is an amount of time while a light year is a unit of distance. In the time it takes the Earth to travel around the sun (584 million miles) light in a vacuum would travel almost 6 trillion miles or almost 9.5 trillion kilometers.

If you travelled at the speed of light, then from the perspective of people here on Earth it would take 600 years however, from your own perspective it would happen instantaneously. It is a hard concept to grasp, but as an object approaches the speed of light, the object experiences a “time dilation” effect in which (for want of a better way to put it) “the clock slows down”. A clock moving at the speed of light would cease to register any elapsed time, and a person moving at the speed of light would neither get any older, nor experience any sensation of elapsed time.

Lets say kebler 22b would a a planet ppl can live in and its 600 lightyears away from earth, how long will it take for us humans to arive there? Il

We are a long way off producing any technology that could transport humans the 600 light years to Kepler 22b. If it was attempted using any form of currently available technology it would take hundreds of thousands, if not millions of years. We simply have not got any method of propelling any form of transport anywhere near the speed of light, nor have we got any method of storing and releasing the amount energy necessary to traverse the distance. There are some, purely theoretical, reasons to suppose that there may be some methods of reducing the actual distance required to traverse the 600 light years by going through (as yet hypothetical ) “wormholes” but that is at the moment pure “science fiction” even though the mathematics that predict their possible existence is sound. A way to visualize how a wormhole might exist is to imagine a piece of paper that is, let’s say 10 inches long. How can we draw a line than spans the distance from the top of the paper to the bottom of the paper without it actually being 10 inches long? - answer - bend the rectangular sheet of paper round to frorm a closed cylinder so that the top of the paper is touching the bottom of the paper. Now you can draw a line that is less than a tenth of an inch long that goes straight from the top edge to the bottom edge. A wormhole is a hypothetical structure that does the same to our 3 dimensional space. How might it work to get to the opposite sides of an inflated balloon “ - just squash the opposite sides together so that they nmeet in the middle, and punch a hole through from one side to the other. Black holes are known to exist, and they really do create that sort of distortion of the space around them, as evidenced by effects such as “gravitational lensing”.

oh i see by the way majikthise you are to smart and wise thanks for clearing this out

oh i see by the way majikthise you are to smart and wise thanks for clearing this out

Actually, light years are generally only used by lay people and in science fiction. Astronomers measure interstellar distances in parsecs. A parsec is the distance away that 1 Astronomical Unit (the distance from the Sun to the Earth) is separated by 1 arcsecond (1/3600 of a degree) of angle. This is about 3.26 light years. This is a very handy unit when you consider that we triangulate interstellar distances by observing an object’s change in position in the Earth sky 6 months apart.

Please tell me if I understand you correctly: A parsec is the distance (around 3.26 light years) at which 1/3600 of a degree of angle makes a difference of 1 AU?

Yes, just another way of explaining it.

A light year is the distance light travels in one year. When you look up into the sky at night, you’re seeing light from stars, planets, and such that is billions of years old. Light travels at a rate of 3.0 x 10^8 meters per second. Since the source(s) of the light that you see at night are so far away, you see “old” light.

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