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Thank you We speak What on earth is a par

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sec A watchman Okay so you're in the kitchen Mom

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ask you to pass her the par sec Well chances

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are she meant to ask for the parsley It would

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be a little hard to hand her a parsecs since

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it's nothing more than a unit of measurement And he

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couldn't exactly set an egg timer to measure one either

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because despite its misleading name ah par sec is not

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a measure of time but a measure of distance Well

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how much distance Well considering we're talking in terms of

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space you can bet it's going to be more than

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on say three or four feet like a light year

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As you may know especially if you've ever time to

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stop Watch light travels at one hundred eighty six thousand

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miles second and there are thirty one million five hundred

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thirty six thousand seconds in a year On a second

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year a light year is the distance light can travel

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in one year so one hundred eighty six thousand times

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thirty one million five hundred six thousand gives us almost

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six trillion miles in a light year Trillian sixteen Yeah

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a par sec is three point two six light years

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for nineteen point two trillion miles a long way But

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why do we need a unit of measurement that seems

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so random aren't lightyears and miles enough Do we really

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need to throw another unit into the next round Like

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all things science there's actually a pretty sensible reason for

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us to use parsecs when calculating interstellar distance well years

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ago Many years ago astronomers and gaze at a star

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from one end of the earth orbit and then they

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see that same star Six months later when earth was

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on the opposite side of its orbit well they realized

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they could get a baseline for a parallax measurement That

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was twice the earth distance to the sun but using

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tried and true measuring methods the numbers and get a

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tad too unwieldy So they pulled the idea of a

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parsecs out of their brains Brains brains where g rated

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insurance the particles the distance at which a star would

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show a one degree arc Wrong Yeah one degree arc

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Second shift if viewed across a baseline of one astronomical

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unit Aii the radius of the earth orbit I got

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this diagram Here's us here's the sun here's the sun

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on weight distance from us to the sun that's one

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You are one astronomical unit So you were on the

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earth and we look at a star located here a

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parallax angle measuring one mark Second is formed See that

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distance from our son too That star yeah one parsecs

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unfortunately it's a little tough to look at a star

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that fits these parameters because well there aren't any No

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stars are even that close thinking really oh snap and

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an arc second is over tiny so parsons won't really

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have too much use to us until telescope for development

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That could make sense of that type of very precise

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information But now that the technology is available it's a

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cinch to measure distances between our son and all the

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other stars out there The next time your mom ask

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you to hand her the part sack while you could

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tell her to go Take a long trip into space 00:03:38.038 --> [endTime] And it won't even be an insult

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