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Light Years E=mc2

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Uploaded by on Oct 9, 2007

Astronomers have more practical units of measurement, such as the light-year, to describe the vast distances between objects in the universe. Because light does not travel instantaneously—in a vacuum, light travels at a finite speed of about 300,000 km/s (186,000 mi/s)—it takes time for light to travel through the universe. One light-year is equal to the distance that light can travel in one year's time, which is nearly 10 trillion km. Thus, Proxima Centauri is about four light-years away. That means that it takes four years for the light emitted from Proxima Centauri to reach Earth. Andromeda is about two million light-years away—meaning it takes two million years for its light to reach Earth.

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  • 0:57 I’m glad Velma found gainful employment after the mystery machine

  • @KinaNafasi

    unconventional means of propulsion ?! They exist , For example Burkhard Heims Stardrive is most of all unconventional , And maybe it is 1 of the 5 mayor means 2 get humankind of this system .

    Some scientists claim that we do have the technology to build 1 of B:H´s at present day , But it will be expensive.. However , it will also be cheap compared 2 some other brainstorm ideas .

    Belive hes engine could take us to mars in under 3 hours . Google Burkhard Heim 4 more info ;)

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  • @heatflash888 From what I can tell she's still hitting those Scooby snacks though.

  • @EGMAG wow you are a retard.

  • @DerEine0101 Not yet but newly discovered sciences may prove to be much help

  • @Buzrazer ty for the info, ill check it out.

  • Maybe couse of tons of junk we left behind on the moon (visable from Earth) .... Maybe from all the tracks that were made by boots and weels ... ( visable from Earth ) Maybe from what they collected from the moon ( Nasa didn´t buy hundreds of moonrocks on ebay )

  • How then can we see Andromeda as it IS now; instead of what it appeared 2 million years ago?

  • WHY do people still think men went to the moon?

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