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Space/Planets

The Milky Way With A Comet Traveling Through.
Picture Source: Kuiper Airborne Observatory, NASA

But the Milky Way is just one galaxy in a sea filled with so many galaxies that they can't be counted yet. I say yet because who knows what the future will bring. It is just amazing how some areas of space are filled with so many galaxies. Remember that our galaxy is an average size one and the Encyclopedia Britannica estimates that there are about 100 Billion stars in it. But not all authorities agree on the amount, with the low point being about 3 Billion and the high end being more than can be counted. The milky way is a spiral galaxy and our sun is out near the end of one of the arms.

Typical Spiral Galaxy similar to our own. Click Here to see where our sun is located. Look carefully for the solid red circle on the right. The indicator is not to scale.

Picture Source: NASA

There are many parts of space just filled with galaxies as I said before. Some are much larger and some are smaller, but all are interesting. The nearest galaxies to our own are the Magellanic Clouds. They are visible to the naked eye and are near the south celestial pole when viewed. Both clouds are about 190,000 light years away. There is a larger Magellanic Cloud and a smaller one.

Large Magellanic Cloud
Picture Source: Anglo-Australian Observatory, Royal Observatory Edinburgh. AAO copyright

From space our galaxy would look like a pinwheel with two smaller galaxies, the Magellanic Clouds, orbiting it. Another galaxy that is close to our own is the Andromeda Galaxy and it also has two smaller galaxies orbiting it.

Andromeda Galaxy
Picture Source: NASA

The Andromeda Galaxy is the closest major galaxy to our own. It is slightly larger than ours but is very similar in all other aspects.

A Multitude of Galaxies
Picture Source: NASA

The amazing photograph above shows hundreds of visible galaxies. What is not so evident is that the photograph also shows that galaxies can collide making up ever bigger galaxies. Without going into the finer divisions of different galaxy types, there four general types of galaxies:

1. Spiral 2. Barred Spiral 3. Elliptical 4. Irregular

Spiral galaxies rotate and have arms that extend outward and usually have a bulge in the center. Elliptical galaxies contain older stars and have very little gas and dust in them. Irregular galaxies are usually full of young stars, dust and gas and have no defined shape.

Spiral Galaxies As Seen Through NASA's Ultraviolet Telescope
Picture Source: NASA UIT

Barred Spiral Galaxy
Picture Source: NASA

Elliptical Galaxy
Picture Source: NASA

Irregular Galaxy
Picture Source: Anglo-Australian Observatory

There are many more interesting objects than the few galaxies I have shown here, but I am saving that for another time. Galaxies are like universes unto themselves. Nobody knows how hard it would be to escape the pull of a galaxy in a space ship. Man may never even be able to travel across his own galaxy, let alone travel between galaxies. The huge distances and unknown and know hazards will be very hard to overcome. Einstein predicted that man could never reach the speed of light. For our sake lets hope either he was wrong or we will find a way around his calculations. Before I end this article here is some food for thought. Galaxies are grouped into clusters, we are in the local group which is about 40 galaxies. All the galaxies in this group are small except for ours, Andromeda and Triangulum. There are also super groups of galaxies and we really have no way of knowing if we belong to a super group yet. Now here is the mind bender, are all the galaxies that we can see part of a group that is part of some larger group, think about it?