Let’s Explore the Galaxies

12 Aug 2016

You probably already know we have a galaxy and it’s called the Milky Way. But did you know there are around 170 billion other galaxies in the observable universe? Let’s explore some of the different types of galaxies to discover what they’re all about.

Galaxies are made up of interstellar gas, dust and loads of stars and dark matter all bound together by a gravitational bond. There can be anywhere from 10 million to 100 trillion stars in one galaxy!

Astronomers have discovered there are four main types of galaxies; the elliptical, spiral, lenticular and irregular.

The Elliptical Galaxy


This type of galaxy is usually very old and doesn’t have any new star formations taking place. The number of stars found in an elliptical galaxy can be anywhere from a few thousand to a billion.The stars inside this type of galaxy are most often very close together. This makes it shine like one big brilliant star. If Earth were inside an elliptical galaxy, we would never have darkness.

Did You Know…Galaxies often crash into each other? Even our own Milky Way has had other galaxies pass right through it.

The Spiral Galaxy


This type of galaxy has long twisting arms. The arms are not only beautiful to look at, but these “circling waves” are responsible for creating new stars. The arms of the spiral galaxy can shine very brightly. This is because some of the stars there are very big and very luminous which lights up the dust and gas in their areas.

However, these big stars don’t have a very long life. This is because they are burning up all their fuel supply. Unfortunately, these big fellas will never be able to leave the arms of the spiral galaxy. The smaller stars, on the other hand, will one day be shot out of the spiralling waves of this galaxy. They will most likely go on to shine in the sky for centuries to come.

The Lenticular Galaxy

The NASA/ESA Hubble Space Telescope has captured a beautiful galaxy that, with its reddish and yellow central area, looks rather like an explosion from a Hollywood movie. The galaxy, called NGC 5010, is in a period of transition. The aging galaxy is moving on from life as a spiral galaxy, like our Milky Way, to an older, less defined type called an elliptical galaxy. In this in-between phase, astronomers refer to NGC 5010 as a lenticular galaxy, which has features of both spirals and ellipticals. NGC 5010 is located around 140 million light-years away in the constellation of Virgo (The Virgin). The galaxy is oriented sideways to us, allowing Hubble to peer into it and show the dark, dusty, remnant bands of spiral arms. NGC 5010 has notably started to develop a big bulge in its disc as it takes on a more rounded shape. Most of the stars in NGC 5010 are red and elderly. The galaxy no longer contains all that many of the fast-lived blue stars common in younger galaxies that still actively produce new populations of stars. Much of the dusty and gaseous fuel needed to create fresh stars has already been used up in NGC 5010. Overt time, the galaxy will grow progressively more "red and dead”, as astronomers describe elliptical galaxies. Hubble's Advanced Camera for Surveys (ACS) snapped this image in violet and infrared light.

The lenticular galaxy is viewed on-edge. It contains mostly old stars and does not have any new star formation activity present. Up to 20% of all nearby galaxies are lenticular in nature. The lenticular galaxy has a bulge in the center of it, but it does not have any arms like the spiral galaxy.

Did You Know…the Milky Way contains around 400 billion stars and possbily that many planets?

The Irregular Galaxy


Around 20% of all galaxies are irregular. This means they are full of gas and dust and usually very small with no particular shape. Because of all this dust and gas, an irregular galaxy has lots of new star formations going on. This can make them very bright.

Now that you have discovered some very cool facts about the galaxies, go out and astound all your friends and family with this new information. If you are in a dark location, take a look up into the night sky. You will most likely be able to see our very own Milky Way on a clear night.