I wonder...

I wonder what was the first nebula discovered?

The first planetary nebula discovered by a human was the Dumbbell Nebula (M27). It was discovered by a man named Charles Messier in 1764, and it happens to be around 1,360 light years away from earth. The dumbbell is a planetary nebula in the constellation Vulpecula. After that in 1790,  William Herschel discovered the NGC 1514, on November the 13, 1790, a planetary nebula with a bright central star. Forcing him to rethink his ideas on the constructions of the heavens. It seems to be 2,283 light years away from earth.

Also, the word "Nebula" is Latin for Mist or Cloud and the term "planetary nebula" is a misnomer that originated in the 1780s with astronomer William Herschel because, when he viewed it from his telescope, these objects resemble the rounded shapes of the planets.

What is the difference between a Nebula and a Galaxy?

Nebula is a cloud of interstellar dust and other ionized gases particular helium and hydrogen. A galaxy, on the other hand, is a huge collection of stars that are held are together by gravitational attraction. A galaxy contains star systems, star clusters along with interstellar dust.

Another fact is Herschel's name for these objects was popularly adopted and has not been changed since.

This taught me that there might be other "planetary nebulas" out there along with galaxies and we could discover more in the future.

Here is a photo of a Nebula