What is a mile?
A mile is an imperial and US unit of length, exactly 1,609.344 meters. The word comes from the Latin mille passus, 'a thousand paces', where a pace was two steps of a marching legionary.
A mile is equivalent to 1760yds or 5280ft.
Road distances in the US and UK are signed in miles, while nearly every other country uses kilometers. Aviation and shipping use the nautical mile instead, which is a different length (1,852 meters).
What is a Parsec?
A parsec is a unit of length used in astronomy to measure vast distances between celestial objects. The term "parsec" is derived from the words "parallax" and "second," which refer to the method used to calculate this unit. Specifically, a parsec is defined as the distance at which an object would have a parallax angle of one arcsecond when observed from opposite ends of Earth's orbit around the Sun.
To understand the concept of a parsec, it is important to grasp the idea of parallax. Parallax is the apparent shift in the position of an object when viewed from different vantage points. In the case of astronomy, scientists use the Earth's orbit as a baseline to measure the parallax of distant stars. By observing a star from opposite ends of Earth's orbit, astronomers can calculate the angle of parallax and subsequently determine the star's distance.
How do you convert Miles to Parsecs?
Divide by about 19.17 trillion. That's how many miles there are in a parsec (19,173,511,576,713 if you want all of it), so even a trillion miles is only about 0.052 parsecs.
Anything measured in miles on or near Earth comes out as a vanishingly small fraction of a parsec. The Moon, at about 238,855 miles, is roughly 0.0000000125 pc away.
Parsecs only start to feel normal at the scale of the galaxy – the Milky Way is roughly 30,000 pc across.