Cosmic Distances: A Walkthrough

The sun is 149,600,000 kilometers away from the Earth and the nearest star (after the sun of course, let's not ignore our good ol' Helios boy) Alpha Centauri is 1,280,000,000,000,000,000 kilometers away from the sun.

Hence, to avoid what I had to do in the above lines (it was a rough time), there has been the establishment of numerous cosmic distances to help us.

1. Astronomical Units (AU): One AU is the distance from the Sun to Earth's orbit, which is about 93 million miles (150 million kilometers). In astronomical units, the 1,400,000,000 km distance from the Sun to Saturn's orbit, becomes a shorter, more comprehensible 9.5 AU.

2. Lightyears: This is the distance a photon travels in one year, which is about 9 trillion kilometers (I won't even try numeris-ing this for dramatic sake) or 63,000 AU. A light-year is how far you'd travel in a year if you could travel at the speed of light (dream stuff for now), which is 300,000 kmps. Light-seconds and light-minutes are also used in the same correspondence.

3. Parsecs: 1 parsec is 3.26 lightyears, to be used when even lightyears seem too complicated for astronomical measuring. Intergalactic distances are defined by "megaparsecs" which are 10 million parsecs.

4. Redshifts: This is the real deal. At distances that render parsec usage complex, displacement of the spectrum of a body toward longer (red) wavelengths is used as measurement. This is caused due to the Doppler effect. More on Redshift coming soon!