Universe Guide

Home / Facts

Galaxy

A Galaxy is a large grouping of stars that orbit round a common point, normall a supermassive black hole which is what is at the centre of our galaxy. Our star `The Sun` is one of many billions of other stars that that make up The Milky Way Galaxy. Our Milky Way is in turn, one of many billions of galaxies that make up the physical part of the universe. Galaxies also include comets, asteroids, nebulas, planets etc. Most galaxies are moving away from us but the famous Andromeda galaxy is moving towards us. No need to panic, it will not happen for millions and millions of years and by that time, the entire human race will have be gone, either dead or on another planet. It had been once thought that all the stars in the Universe was in the Milky Way but that all changed in the 1920`s during what is known as the Great Debate,

What is at the centre of the galaxy?

No-one knows for sure, some say it`s a super-star, a collection of bright stars or a super-black hole. The centre of the Milky Way is so far away, we`ve not yet been able to determine what is there as yet. What we do know is that we are in the suburbs of the galaxy.

Galactic Center of the Milky Way in Sagitarrius

Where is the centre of the Milky Way, our Galaxy?

Jan Hendrik Oort calculated that the centre is in the direction of the constellation of Sagittarius . The centre of the Galaxy is commonly referred to as Sagittarius A*. It is estimated at a distance of 26,000 Light Years from Earth.

What is the difference between The Solar System, a Galaxy and the Universe?

A Solar System is the smallest of the three subject matter, it covers the area of a Star`s Heliosphere. Inside the solar system is the star and all the orbiting Planets, Asteroids, etc. A solar system may not even contain any planets. A Galaxy is a grouping of stars made up of millions and billions of solar systems. The Universe is the biggest of all, it encompasses everything there is, including every galaxy, every star, all matter, everything full stop.

How far away is the centre of the Milky Way, our Galaxy?

The centre of the Galaxy is estimated at between 25,000 light years plus or minus a few thousand. We are at the edge of the galaxy so getting out of the Milky Way is quicker that getting to the centre. A light year is 5,878,625,373,183.608 miles, therefore the centre of the galaxy is very very far away.

What`s the nearest Galaxy to us?

Excluding the Milky Way, the nearest galaxy to us is the Andromeda Galaxy which is 2.5 million light years away. It won`t always be the case though, whilst most galaxies are moving away from us, the Andromeda galaxy is moving towards us with an expected collision happening in approximately 4.5 Billion years time so you got nothing to worry about then. When the galaxy hits us, it is expected that the Milky Way may end up looking like the Tadpole Galaxy, in the constellation of Draco. It is 400 million light years away.

How did the Milky Way got its name?

Different religions/regions have different views as to how the galaxy came into creation. The term comes from Roman/Greek mythology where after the birth of Heracles, Hera spilled her breast milk in anger of not being the babys mother. Another variation says that it was spilled when Heracles was caught drinking Hera`s milk and was pushed off. The word galaxy derives from the greek word for milk, gala. In the beginning, when they looked up at the stars they saw a cloudy/milky area hence the name.

What are the Galaxy Classification?

A galaxy may be referred to as a NGC or M number, what are they? Galaxies, Nebulas and star clusters were first catalogued by Charles Messier, a French Astronomer. His first catalogue consisted of45 was published in 1774 then grew to 103 in 1781 then finally 110. Later in 1880, the new General Catalogue was started by J.L.E.Dreyer using observations from Sir William Herschel. It contains nearly 8000 objects. Some objects can have both a M number and a NGC number as well. For example, the Andromeda Galaxy is known as both M31 and NGC224.

What is the largest Galaxy?

At the moment, the largest galaxy we know of is the IC 1101, an elliptical galaxy that is at the heart of a group of galaxies known as the Abell 2029 Galaxy Cluster. The galaxy was discovered by Sir William Herscel. The galaxy is estimated at being over 6 million light years in diameter with trillions of stars. To put that in context, the Milky Way is a 1/50th the size of the IC 1101. The IC 1101 can be seen in the constellation of Virgo.

What are the types of Galaxies

There are four main types of Galaxies, ( Spiral, Lenticular, Irregular and Elliptical ). There are subtypes as well, for example, clockwise spiral and anti-clockwise. The best way to explain the different typesis to show you what they look like. The Andromeda galaxy is . Irregular Galaxies also include Starbust Galaxies and Ring Galaxies, example of the former is below. Irregulars lack any shape or definition that the othertypes do hence their name. Lenticular are said to be lens like in nature.


SpiralLenticular
Spiral Galaxy - M31Lenticular - NGC2787
 
EllipticalIrregular
Elliptical Galaxy - M87Irregular Galaxy - M82

Galaxy Collision

Whilst most galaxies are currently moving away from us as a result of the Big Bang. The Andromeda Galaxy is currently on a collision course with the Milky Way. It is moving at a 75 miles a second. Whilst on Earth, that is a super fast speed, it space, it is not that fast considering how far away the Andromeda galaxy is from us. The Andromeda Galaxy is not expected to hit Milky Way for at least 3 billion years. In 3 billion years, the human race unless it has got off this planet will no longer exist because The Sun would`ve made the planet inhabital. The below video is something that NASA shared on Youtube which explains more about galaxy merging and how the MIlky Way and Andromeda galaxy will merge.



Video of two galaxies (Andromeda and Milky Way) Colliding



NameMessier_TypeConstellation
M110Satiellite Galaxy of M31Andromeda
Le Gentil Satellite Galaxy of M31Satiellite Galaxy of M31Andromeda
Andromeda GalaxySpiral GalaxyAndromeda
NGC1569Dwarf Irregular GalaxyCamelopardalis
Whirlpool GalaxySpiral GalaxyCanes Venatici
M106Spiral GalaxyCanes Venatici
M94Spiral GalaxyCanes Venatici
Sunflower GalaxySpiral GalaxyCanes Venatici
M77Spiral GalaxyCetus
M85Spiral GalaxyComa Berenices
M88Spiral GalaxyComa Berenices
BlackEye GalaxySpiral GalaxyComa Berenices
M91Spiral GalaxyComa Berenices
M98Spiral GalaxyComa Berenices
M99Spiral GalaxyComa Berenices
M100Spiral GalaxyComa Berenices
Large Magellanic CloudDwarf GalaxyDorado
Spindle GalaxyLenticular GalaxyDraco
Tadpole GalaxyBarred Spiral GalaxyDraco
NGC1300Barred Spiral GalaxyEridanus
NGC 6050 Interracting Spiral GalaxyInterracting Spiral GalaxyHercules
M83Spiral GalaxyHydra
M65Spiral GalaxyLeo
M66Spiral GalaxyLeo
M105Elliptical GalaxyLeo
M95Spiral GalaxyLeo
M96Elliptical GalaxyLeo
Pegasus Dwarf Irregular GalaxyDwarf Irregular GalaxyPegasus
Pegasus Dwarf Spheroidal GalaxyDwarf Spheroidal GalaxyPegasus
M74Spiral GalaxyPisces
The Triangulum GalaxySpiral GalaxyTriangulum
Small Magellanic CloudDwarf GalaxyTucana
M108Spiral GalaxyUrsa Major
M109Spiral GalaxyUrsa Major
NGC2787Lenticular GalaxyUrsa Major
Pinwheel GalaxySpiral GalaxyUrsa Major
M102Spiral Galaxy ( Maybe 101 )Ursa Major
Bodes GalaxySpiral GalaxyUrsa Major
Cigar GalaxyIrregular GalaxyUrsa Major
M84Lenticular (S0) GalaxyVirgo
M89Elliptical GalaxyVirgo
M90Spiral GalaxyVirgo
M86Lenticular (S0) GalaxyVirgo
M87Elliptical GalaxyVirgo
M58Spiral GalaxyVirgo
M59Elliptical GalaxyVirgo
M60Elliptical GalaxyVirgo
M61Spiral GalaxyVirgo
Sombrero GalaxySpiral GalaxyVirgo
M49Elliptical GalaxyVirgo
IC1101 GalaxyElliptical GalaxyVirgo

Add a Comment


Name:
Email: (Optional)
Comment:
   

Anonymous
This was the only website I could find that had all of the information I needed in one place in plain English. Thank You.