The Night Sky
August 2021
Here in Embsay we are blessed with wonderful views and nature around us, albeit being nibbled away by the relentless march of new housing and high intensity lighting. Nature is precious and often we forget and assume it will remain unchanged around us. For many, nature is limited to our immediate surroundings, but when we look up into the night sky we are just a speck of all nature. The scale and distance of objects conceal the reality of the situation. We live on a rock (Earth!) spinning 1000 miles an hour and circling the sun at 67,000 mph, yet I am deceived into thinking that I am standing quite still. Even looking up into the night sky things do indeed look unchanged year after year. However, the stars, whilst appearing a similar size to each other, trick us into thinking they are roughly the same distance away. Deceived again! Each star we look at has a vastly differing distance and size. For example, take two familiar stars, one called Sirius takes 8.6 years to send its light into your eye (double the size of our sun), but Deneb takes 1500 years (two hundred the size of our sun)! Yet they both look like similar dots in the night sky. Even the familiar patterns of the constellations are changing ever so slightly each year, century and millennia. Finally, one of the most astounding facts is that when we do spot an object with our eyes it is as it was when the light left the object, often thousands or millions of years ago. We are seeing the ancient past, probably an image of something which has changed beyond all recognition.
Despite all of this, we can predict and we are very good at doing this. In the past, predicting when an eclipse was due to take place would have been met with great suspicion or adoration. I hope the latter as I predict this month’s highlight. In 1862 a great Comet visited Earth’s orbit leaving a trail of material across Earth’s path. We cross this point each year between the 12th & 13th of August on our journey around the sun. These tiny pieces burn up or bounce off our atmosphere to create a meteor shower called the Perseids. Often the moon is so bright it can wash out the sky but this year it is just after a new moon, so cross your fingers for a few clear nights. In my experience it is best to look out for the meteors late on the 12th August around midnight / early hours of 13th August. Look East and half-way up the sky. The Comet that created the path of tiny pieces is called Swift-Tuttle and returns every 133 years. It was rediscovered around 1992 and will become visible again in 2126. Here is a link to the Natural History Museum for this and other Meteor showers.
Whilst you are out looking upward on a dark, clear night, try and search out the constellation of Cygnus (the Swan). It is easy to find as it is almost overhead at this time of year. Its long neck heads south and its tail is the bright star Deneb already mentioned in this article.
There are too many wonderful things to list here as you gaze around this spot in the sky. Most are out of reach to the naked eye but with binoculars you may see some of them. For me, a prize must go to the aptly named North America Nebula. Here is an image I took from Kielder, Northumberland. I just opened the shutter of my camera for 180 second and gathered all the light up all in one go!
(Photo Milan Davidovic)
It is almost four full moons’ width across when observed from Embsay. It is a huge cloud of interstellar gas, and within it are young stars lighting up the region.
Don’t miss the head of the Swan either as it is made up of a double star, Albireo. One golden and one blue, an amazing double that is famed amongst astronomers for its colour contrast.
(Photo by Bob Franke)
Hope you spot a few meteors and explore Cygnus for yourself.
Clear Skies
Milan Davidovic
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