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Light years are more convenient when measuring the enormous distances of space. One light year is 5,869,713,600,000 miles so it is much easier to use light years, especially when many objects in space are hundreds, thousands and millions of light years from Earth.

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11y ago
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14y ago

Let's take an example:-

Our nearest star - Alpha Centauri is:-

* Light years 4.37 * Parsecs 1.34 * Kilometers 4.13 x 1013 * Meters 4.13 x 1016

Betelgeuse is :-

* Light years 640 * Parsecs 197 * Kilometers 6 x 1015 * Meters 6 x 1018 IOK-1 (The furthest Galaxy Known)

* Light years 12.9 billion

* Parsecs 4 x 109 * Kilometers 1.22 x 1023 * Meters 1.22 x 1026

Which one is easier to remember?

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13y ago

There are two main reasons he light year is more convenient than miles.

Firstly space is very big. If we were to measure everything in miles it would become harder to comprehend for the layman to comprehend the difference in distances.

Let me give you an example. Take 3 stars & a galaxy:- the Sun, Proxima Centauri, Betelgeuse & the Andromeda galaxy.

The Sun is 92955887.6 miles away. This is OK but when we look at Proxima it is 24635923200000 miles away, Betelgeuse is 3754045440000000 miles away & Andromeda is 14664240000000000000 miles away. To most people these are just meaningless numbers.

Even if you use scientific notation the Sun is 9.9256*107 miles, Proxima 2.4636*1013, Betelgeuse 3.7540*1015 & Andromeda is 1.4662*1019 it is still pretty much incomprehensible to anyone that is not a mathematician.

If you use light time to display the distances, the Sun is 8 light minutes, Proxima is 4.2 light years, Betelgeuse is 690 light years and Andromeda 2.5 million light years it becomes obvious to everyone relative distances.

Another reason why using the light year is so we can tell when long ago the light left the star. For the Sun we see it as it was 8 minutes ago. If is was suddenly to stop shining we would no nothing until 8 minutes later. We see Proxima as it was 4.2 years ago, Betelgeuse 690 years ago and Andromeda 2.5 million years ago.

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13y ago

A light year is equal to approximately seven trillion miles. Our own galaxy, the Milky Way, is 200,000 light years in length on its major axis (80,000 light years on the minor axis) so there are lots of stars which are tens of thousands of light years away from us. Expressed in miles they would be on the order of hundreds of quadrillion miles away, and that is just an awkwardly large number.

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13y ago

Since one light year is about 5879 billion miles, the number of miles involved becomes cumbersome when you are dealing with extreme astronomical distances; for example some of the latest galaxies viewed by the Hubble telescope are 13 billion light years away. It's just a better unit of measurement for larger distances.

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13y ago

It's the same reason it's easier to use kilometers instead of inches, for measuring certain distances. The longer the distance is, the greater the need for a meaningful unit. For example the nearest galaxy to us is the Andromeda Galaxy, at 2,500,000 Light Years. One Light Year is 10,000,000,000,000 kilometres, meaning it is 25,000,000,000,000,000,000 kilometres away. Clearly kilometres are not a suitable unit for expressing such distances.

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12y ago

These Units are more related to the scale of Astronomy and gives smaller numbers to manipulate.

One AU is 93 million miles. Astronomical distances are thousands, or hundreds of thousands, of AUs - gazzillions of miles are less easy to manipulate!

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7y ago

The kilometer is a perfectly acceptable unit with which to describe the sizes of galaxies

and the distances between stars. It's just that if you use the kilometer, then the numbers

you have to handle are roughly ten trillion times bigger than they would be if you used the

light year instead, which quickly becomes quite inconvenient.

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11y ago

Meters, and even kilometers are so tiny they are virtually nonexistent compared to the vast distances involved in astronomical observations. Light years are at least at a scale where some galactic distances can be easily manipulated and to a degree grasped. It is a matter of suitability and proportion. We wouldn't measure our height in units consisting of one millionth the width of an electron.

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11y ago

It is more useful for expressing the distance to stars because one light year is 9.461 x 1015 meters so it helps astronomers to avoid having to use very large numbers. Even so they still have to use very large numbers.

A preferred unit is the Parsec, which is the distance to a star that has a parallax of one second of arc. That means its apparent position in the sky changes by one second of arc when viewed from either end of a baseline of one astronomical unit, which is 149.6 million kilometres. A parsec is 3.085 x 1016 meters, or 3.26 light years.

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Q: Why do astronomers use units like light years instead of miles?
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Is the apparent movement of a star used to measure its distance from Earth?

One common distance standard is the AU - Astronomic Unit which is about 150 000 000 km the average radius of the Earths orbit around the Sun. 1 AU is equal to exactly 149,597,870,700 metres (92,955,807.273 mi)


Why do you measure using standard units instead of measuring with any kind of units?

Standard units are more commonly used than non standard units. Also, many of the conversion factors, such as the Universal Gravitational Constant or the Speed of Light, are in standard units and, if your measurements were not in appropriate units, you would need to convert.


Why do astronomers use light years insted of kilometers to mesure distances of stars?

Any length or distance can be expressed in any unit of length, but some units may result in inconveniently large or small numbers. When you talk about distances between stars, light years produce numbers that are much more convenient than kilometers would produce, just as it's a lot more convenient to talk about your drive to work in miles instead of inches. The nearest star outside of the solar system is roughly 4.3 light years away. That's a lot easier to read, say, and remember, than 40,680,000,000,000 kilometers.


Why should si units be used instead of other units?

There are different units for measuring different attributes.


What is the conversion of light years to astronomical units?

1 light year = 63,240 Astronomical Units

Related questions

What is used to measure space?

Units of volume are. For big distances, astronomers use "light years" and "parsecs". A light year is the distance that light travels through space in one year.


What do astronomers use measure to distances to nearby stars?

Two units that are commonly used are:* Parsecs (among professional astronomers) * Light-years (in popular astronomy) A light-year is about 9.5 million million kilometers. A parsec is about 3.26 light-years.


What is the speed of Light in US units?

186,282.397 miles per second


How are light years and astronomical units similar?

Light years and astronomical units are both units of distance.


What do astronomer usually measure distance to stars with what units?

Light years. Strictly speaking, professional astronomers use "parsecs". However they also use light years, which are better known to most people.


Is the apparent movement of a star used to measure its distance from Earth?

One common distance standard is the AU - Astronomic Unit which is about 150 000 000 km the average radius of the Earths orbit around the Sun. 1 AU is equal to exactly 149,597,870,700 metres (92,955,807.273 mi)


If the speed of light is 2434546?

You do not state the units. The speed of light is 300,000 kilometres per second, or 186,000 miles per second.


What do astronomers use to measure distance to stars?

If you refer to the units, both the light-year and the parsec are often used. A light-year is the distance light travels in a year; about 9.5 x 1012 kilometers (9.5 million million kilometers). A parsec is about 3.26 light-years.


How many miles is in 63 light years?

6 million trillion (6,000,000,000,000 x 1,000,000).__________________________________________________________1 Light Year = 5878625373183.61 Miles = 5.87862 billion miles (according to SI measurement units)1 million light years = 5.87862 trillion miles = 5.8786 x 10E18


What is the standard speed in miles per hour of the light if a travels at 15000 kilometers per second?

From my understanding the speed of light in metric units is 300,000 kilometres per second. 1 mile = 1.609 kilometres 300,000/1.609 = 186,451.2119 miles Therefore the speed of light in imperial units is 186,451.2119 miles per second There are 3,600 seconds in 1 hour 186,451.2119*3,600 = 671,224,362.8 miles per hour So the answer to your question is that light travels at 671,224,362.8 miles per hour.


I am 12 miles from the tower how many square miles does that equal?

Miles and square miles are units of different measurements. Miles are units of length and square miles are units of area. There is no answer to your question.


Do astronomers measure the distancein the solar system in kilometers?

no the measure it in AU'S =ASTRONOMICAL UNITS