As just about everyone knows, the name the milky way is a common name given to our galaxy, a vast whirlpool of stars, probably about 300 billion, where our Earth lives, it takes light about 100,000 years to cross it, so it’s pretty big.
How many galaxies are there?
We used to say about 200 billion, but not any more, we now reckon there about 2 trillion galaxies discovered, the result of all the latest discoveries by NASA. I’ve never met anyone who could truly appreciate the immense size and distances involved, it’s all too far from human experience, but still true.
Going back to our not so little corner of the universe, my own father was a young man when Hubble discovered that our galaxy wasn’t alone in the universe – he coined the phrase ‘an island universe’, quite poetic. Hubble discovered a special type of star in the Andromeda Galaxy (a cepheid variable) that enabled him to place Andromeda outside our galaxy by a considerable distance and also to prove that the universe is expanding constantly. This means that cosmology was born in the 1930s, not all that long ago, and being a young science we have a very long time to wait before we can say that we truly understand most things about the universe.
So when you look up in a very dark and clear sky at the smudge of light crossing over, what are you looking at? You are seeing millions of stars of all types forming one of the arms of our galaxy. You are looking through space outside our region, on to the next limb of our galaxy. Impressive isn’t it.
If you want to see this, you do need completely dark and clear skies, no street lights, no cloud, for me this used to be easy living near the North Yorkshire forest, but now in Torrevieja it’s almost impossible without travelling somewhere suitable. How do we find somewhere suitable? That’s surprisingly simple, there’s a scale of dark skies called the Bortle scale and a quick look online will give you a map of our local area showing the dark sky areas. Just Google Bortle and look at a map. The lower the number for an area the darker the sky so 1 is perfect and very rare. The milky way will be visible from 4 or better on the scale. If you are going to make a trip out to observe, don’t forget about the moon, a bright nearly full moon will destroy a dark sky, so check first.
That’s all for this month, enjoy stargazing.

Charles Oates, Vega Baja Astronomy Group.

To find out more about observing and astronomy why not join our group,
email us at vegabaja.astronomygroup@gmail.com for more information.