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The complete history of the Universe -- from the Big Bang to 200 my into the future

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History of the Universe eBook. 398 pages, 300 illustrations only $2.99

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Light-Year

In the PennySystem scale, 1 meter represents about 39.53 light-years, that is, the distance that light would travel in 39.53 years. The term light-year is often misunderstood. A light-year is a measurement of distance, not of time.

It is the distance light travels in one year. Light is used to measure distance since it is the fastest thing in the Universe and its speed is constant and very well known by accurate measurements.

Light travels at about 300 million meters per second. It takes light about 5 hours to travel across the solar system, so a light-year is much bigger than this. The nearest star to us (apart from the Sun) is Proxima Centauri, which is about 4 light-years away.

We live inside a disc of stars (the Milky Way Galaxy) which measures about 100,000 light-years across and around 2000 light-years thick.

A light-year equals about 9.46053 x 1012 km (or 5.878 x 1012 miles).

That is, almost 1016 meters.

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History of the Universe eBook. 398 pages, 300 illustrations only $2.99

eBook only $2.99
398 pages, 300 images

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