Spiral Galaxies

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Our wonderful universe is full of undiscovered scenes. Looking at the sky at night, stars are tiny speks in the sea of night. Zooming into the great beyond looking back at our universe from a distance, galaxies themselves become like tiny speks, like the sand of a beach, unmeasurable. 

Below, we will be looking at some stunning images of galaxies from a side view. We will focus our attention on spiral galaxies. Keep in mind that there are four main types of galaxies. Ellipticals, irregular, quasars and spirals.

Our own galaxy, the Milky Way, is a spiral,  like a pinwheel, with lots of gas, dust and young stars. In fact, most spiral galaxies are known to be among the brightest in the universe, except for quasars, which are compact objects emitting astronomical amounts of energy. Thankfully there are none near by.

A galaxy is an enormous collection of gas, dust, asteroids, planets and stars all held together by gravity. Our planet Earth is part of the solar system which consists of 9 planets, asteroids and our Sun. Our Solar System is one of a great many other solar systems that are part of our galaxy, the Milky Way.

The Milky Way in Stars and Dust
Credit & Copyright: Serge Brunier
Source: https://apod.nasa.gov/apod/ap051004.html

Spiral galaxies are the most common type of galaxies in the sky. In fact, about 77% of galaxies are spirals. And not surprisingly they have the form of a spiral. Our Milky Way galaxy fits this category. Has long arms spiraling towards a central bulge. If you can clearly see its spirals, it's called a Face-on spiral, but when you see it from the side, is called an Edge-on spiral.

Some spiral galaxies are wound tight while other have loose arms.

Below you can see some examples of spiral galaxies

M101: The Pinwheel Galaxy
Credit & Copyright: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT 
Source: https://apod.nasa.gov/apod/ap030310.html

NGC 1365: A Nearby Barred Spiral Galaxy
Credit: FORS Team, 8.2-meter VLT Antu, ESO 
Source: https://apod.nasa.gov/apod/ap030413.html

M31: The Andromeda Galaxy
Image Credit & Copyright: Robert Gendler 
Source: https://apod.nasa.gov/apod/ap181217.html


To learn more about galaxies, you can click on the following links:

Nasa  https://www.nasa.gov/subject/6894/galaxies/

ESA/Hubble https://esahubble.org/images/archive/category/galaxies/

ESO https://www.eso.org/public/images/archive/category/galaxies/

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