Whirlpool Galaxy: Messier 51

Messier 51: Whirlpool Galaxy M51a (left) and M51b (right)

At 31 million light-years away, Messier 51 is actually two interacting galaxies. In this photo, M51a (the Whirlpool) is the larger spiral galaxy. The smaller companion, M51b, is classified as a dwarf galaxy and is seen at the end of one of the spiral arms of M51a.

Before Copernicus and Galileo, people believed that Earth was the center of existence. The sun, the stars and planets revolved around us. After all, that is exactly how it appeared to be (with the exception of a few 'wanderer' planets and occasional passing of comets).

With the advent of advanced mathematics and the birth of the telescope, humans made discoveries that led to many realizations; that Earth is not the center of our solar system. The Sun is not the center of our galaxy.

Before we were aware of galaxies other than our own, the state of technology limited our ability to understand objects in the night sky. The term nebula was widely used to classify objects due to their 'mist' like appearance. Borrowed from the Latin language, nebula literally means 'mist'.

M51a was discovered by Charles Messier in 1773. The companion galaxy (M51b) was discovered by Pierre Mechain in 1781. It was not known at the time that these two galaxies were actually interacting. In fact, it still wasn't even known that they were galaxies. In 1824, William Parsons discovered the spiral structure of M51a.

In 1924, Edwin Hubble made the most momentous and pivotal discovery; other galaxies exist outside of our own. Armed with this new perspective, people began reassessing objects previously identified as nebulae to see if they were actually galaxies. Radio astronomy was eventually able to prove that M51a and M51b are indeed gravitationally interacting.

My first experience imaging M51 was in February, 2020. I was absolutely stunned with what a telescope and camera is capable of seeing from my yard. It was nearly as extraordinary of a feeling as the first time I saw Jupiter through a telescope. Here is a comparison of my Feb-2020 vs. Mar-2021 images of M51:

"The world as we have created it is a process of our thinking. It cannot be changed without changing our thinking." - Albert Einstein