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Why is a parsec named so?

Answer 1

Parsec is an acronym for 'parallax second'. It is a unit of distance used for measuring distances of deep sky objects. 1 parsec = 3.26156 light year.

Consider an isosceles triangle with equal sides measuring 1 parsec and opposite side 1 AU against an angle of 1 second = 1/3600 degree. A larger unit is mega parsec, or 1 million parsec.

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Answer 2

Hunter Arthur

The term "parsec" was coined to combine the terms "parallax" and "second." Parallax is the apparent shift in an object's position when viewed from different angles, and "second" is a unit of time or angle. A parsec is defined as the distance at which one astronomical unit subtends an angle of one arcsecond due to parallax.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.