Distance. One light-year is the distance that light travels in one year.
Light travels at 186,000 miles per second, or 300,000 kilometers per second. This speed is sometimes abbreviated as "c".
a light year refers to the distance it takes light to travel in one year, in practice, if you were one light year from the earth, and had a telescope powerful enough to veiw activities on the surface, you would be seeing activity's one year in the past from the moment you are viewing them, becasue the light waves you are looking at would have taken a year to get to where you are viewing them from... If you are asking: What do astronomers mean when they say that powerful telescopes look back into the past, that is because of the speed of light and 'light years'.
Although very fast indeed, light does not move instantly as it seems; it takes time to reach us from very, very distant objects such as stars. A light year is how far light will travel in a year = 9,400,000,000,000km. Stars are much much farther away than that, so what we see of them is actually how they looked years ago, but the light has only just got here.
Seeing something, anything, is literally receiving light from it to your eyes - either reflected off it (the Moon, that coffee mug, your sister's face) or produced by it if it is a light source (a star, your PC screen, a light bulb).
So, if a star trillions of kilometres away blew up yesterday, we will not see the explosion (called a super nova) for many years yet. All this means that as we develop better, more powerful telescopes, we can see right back towards the beginning of the universe and the largest explosion of all: the Big Bang. Just don't ask what there was before that, because the answer is nothing, no light, not even time!
No. A light-year is a measure of distance; the distance that light travels in one year.
Light travels at approximately 186,000 miles per second, or 300,000 kilometers per second. There are 60 seconds in a minute, 60 minutes in an hour, 24 hours in a day, and 365.24 days per year. Multiply all those numbers together, and that's how far a "light-year" is.
The nearest star to our Sun is Proxima Centauri, at about 4.2 light-years. For comparison, the distance between the Earth and the Sun is 500 light-SECONDS.
A light year is a measure of distance. It is the distance that light travels in one year. 1 light year = 9,460,528,400,000 kilometers = 5,878,499,810,000 miles
"Light-year" is a unit of distance. It's the distance that light travels
through vacuum in one year. Roughly 5,878,700,000,000 miles.
It measures distance. It goes by the distance light can travel in one year. It is about 10 trillion kilometers.
NO, light years measure distance more specifically the distance light travels in a year
No, a light year is a measure of distance.
Fundamental unit all examples
yes it is distance
A light-year is a unit of distance, not a unit of time.
kilometer, AU (astronomical unit), light year, parsec.
An astronomical unit is not larger than a light year. A light years is considered to be approximately 62,000 times larger than an astronomical unit.
light-year
The light-year is the distance light travels in a year. Since this sometimes causes confusion, please note that a light-year is a unit of distance; NOT a unit of time. A light-year is approximately 9.5 x 1012 kilometers. (A light-year is defined to be exactly 9,460,730,472,580,800 metres.)
One thing that complicates matters slightly is that there are lots of things called "years", and they're all very slightly different. However, the fundamental SI unit of time is the second, so any other time unit is "derived" from that (with the possible exception of "Planck time", which is about as fundamental as it's possible to be since it's based on universal physical constants).
A light-year is a unit of distance, not a unit of time.
An Astronomical light unit (ALU) is a term derived to compliment a light year. It was devised by Wiki supervisors to alleviate the problem of people worrying about how a measure of distance could be related to time. "How long is one light year". It does not replace a light year, merely its usage is less confusing and the values stay exactly the same.
A light year is larger than an astronomical unit.
False the light year is not a unit of time it is a unit of distance true.
The unit of measurement is the "light year".
One Light-year is 63,024 Astronomical units.
"Light-year" is NOT a unit of time. It is a unit of length or distance - the distance light travels in a year.
"light-year"
This is an impossible conversion to make. A hour is a unit of time. A light year is a unit of distance, specifically, it is the distance light travels in a year.
A light year is a unit of length equal to just under 10 trillion kilometres.
A light year is about 63,000 times greater than an astronomical unit.