#clearskies! #astronomyatdovestone #finalydark #bringbackthenight #astronomyinthevalley

 

From November look East from about 24:00, the unmistakable shape of Orion the great Hunter will appear above the horizon, as the winter gets closer the Constellation will arrive earlier and earlier. The bright star in the top right hand corner, Betelgeuse, a red supper giant. If you draw a line from Orion's Belt down to the horizon you’ll come across the brightest star in the Northern Hemisphere, Sirius. One of the best images of Orion is the Great Nebula of Orion. Find the Belt of Orion and you;; see his sword, about half way down the sword you’ll find the Greta Nebula, using the naked eye it is just about visible, but with binoculars you will make out a grey fuzzy object that you would mistake for a cloud, using a telescope of four inches or more you will be able to make out some structure of the nebula.

 

Drawing a line from the belt in the other direction you’ll come across a smudge, this is M45, the Pleiades, a Star Cluster that orbits around our Milky Way. At a distance of around 444 light years away it is only the seven brightest stars that can be seen hence its name the Seven Sisters. The brightest is Alcyone.

 

From dark sky sites the Milky Way will be visible. We sit in the spiral arm of the Galaxy, when we look out we can see the arm, the higher density of stars give it an appearance of a smudge, or faint cloud across the sky. Look for Cassiopeia, a distinctive constellation in the shape of a ‘W’. The Milky Way runs like a line through Cassiopeia.

 

As the dark skies get darker and earlier from the darkest of sites you can make out Andromeda, our neighbouring Galaxy. The Milky Way is not alone in space; we have a number of galaxies near to us, called The Local Group. Andromeda is one of these. It is about 1.3 times larger than the Milky Way. Look due west and find Cassiopeia. From the middle point of Cassiopeia go down to the bottom tip of the ‘W’ heading towards the horizon, Andromeda sits on this line. A pair on binoculars will enable you to see it as a disk shaped smudge but a telescope of 4 inches or bigger will resolve the galaxy.

 

The star of the Winters Astronomy is in fact the planet Venus, known as the evening star. Because its so close to the sun its difficulty to see and isn’t visible at all during the night. From the end of November, look South West just after the sun has set. Venus is visible as a bright star just above the horizon.

 

The best Meteor shower of the season, the Geminids, begins on the 7th of December and ends on the 16th, but the peak is on the 14th of December. Meteor showers are given there name depending on where in the sky the appear to originate from. In this case the constellation Gemini. The source of the meteors is the asteroid 3200 Phaethon, making the Geminids only one of two showers not from a comet! Because of this they have trace amounts of metals causing the shooting stars to have a variety of colours!

 

 

Happy New Year seems to be the best way to start the first blog of the year, and already what a start! So much has happened in astronomy and space exploration!

On the 1st of January we finally got to see the high resolution photos of the bizarrely shaped snowman-esque Ultima-Thule asteroid. Then, on the 3rd of January, the chinese lander Chang’e-4 landed on the far side of the moon. There are also really exciting things happening at Virgin Galactic, and it won't be long until space flight is much more accessible to many. I say many and not all...yet! And all of this within the first week of the year! The Chinese lander Chang’e-4 is the one that has excited me the most!

First, a bombshell: the excellent Pink Floyd album The Dark Side of the Moon is not actually about the moon, but more about the stresses and lunacy of everyday life. I have been living in blissful ignorance of this! I guess we should also address the title, The Dark Side of the Moon. This implies that one side of the moon is always in shadow and one side in light. This isn’t the case. It refers instead to the fact that only one face of the moon faces Earth.

 

 

The planet Thia, colliding with Earth, the debris from this collision is thought of of formed our moon!

 

The moon was created 4.5 billions years ago, around 20-100 million years after the solar system. The solar system at this point would have been a chaotic, violent pinball machine, where hundreds of planets were playing a massive game of chicken. A planet, Thia, collided with Earth,

its core combining with our own planet to eject a mass of material into orbit.

Over millions of years this material, with a little help from gravity, clumped to form our own little satellite: the moon! The iconic image of the ‘man in the moon’, the massive lava flows which make up the traces on our moon’s face, are a reminder of this turbulent beginning.

 

 

Our Satellite, the features that make up the moons 'face' are lava flows, not craters!

 

 

The moon and Earth are bound to each other gravitationally, a force resulting in the product of the Earth and Moon’s mass. The same force keeps the system ‘glued’ together. The only reason it is the moon orbiting us rather than the other way around is because we are more massive! We do experience this force on Earth and it’s no more visible than in the effect it has on our massive bodies of water.

 

The gravitational attraction due to the moon creates our tide. The Moon ‘locks’ the water in place and the Earth effectively rotates underneath. The frictional force between the Earth’s surface and the water is causing the rate of rotation of the Earth to decrease or, more simply put, the water is slowing down the rate at which the earth spins! So yes, our days are getting longer!

However, angular momentum must be conserved! Angular momentum is much like linear momentum, which is a product of the object's mass and velocity. Now, if the Earth’s momentum is decreasing, then something in the system has to increase. This is the moon’s angular momentum. An increase in the Moon’s angular momentum propels it to a higher orbit.

The result of this is that the moon is locked into what’s called a synchronous orbit. The time it takes to spin through its own axis is (roughly) equal to the time it takes to move around the Earth. The result… the near side of the moon is always facing the Earth and the darkside, or more appropriately the far side, of the moon is cast to face outwards, away from Earth.

 

 

The images being beamed to Earth from Chang’e-4 is a view of the moon that was not seen until 1959, when Soviet orbiter Luna 3 orbited the moon and is a view that only 27 people have laid eyes upon. That image of the chang’e-4’ lander photographing the roverand its its tracks, leading away from the lander off to explore, is going to be one of those iconic images of Luna exploration. It really was one of those hair tingling moments. Fingers crossed for the rest of 2019.

Get a bit close to our nearest neighbour at one of our events, check out our events page at www.yorkshireastronomy.com or email us at info@yorkshireastronomy.com to arrange a Practical Astronomy Workshop.

Whilst walking the dog at a barmy 05:00 I took the chance to stop and look at the sky. We are so lucky to have such an incredibly clear and relatively unpolluted sky to frame our view. It is so easy to get into astronomy – it’s not some snobby scientific past time that demands a PhD in astrophysics. Yes, to understand all the elements involved and try to explain them is definitely complicated, but to appreciate them is the first step on the road to beginning the journey into physics and astrophysics. It also requires nothing apart from a bit of luck and our eyes!

 

Winter is the astronomer’s best friend. As soon as the clocks go back, the sky becomes so much more accessible! I like to sit waiting for the dog while it sniffs another bit of the track and make my own constellations out of the groups of the brightest stars, just like someone did thousands of years ago to make the constellations that we now find more familiar in deciphering our fortunes!

 

There is also the Pleiades, or the seven sisters, an open cluster of stars that looks a bit like a smudge. If you look east at about 20:00 and about a third of the way up from the horizon you’ll find this beaut to a group of stars. The seven brightest stars give the cluster its name, but it’s actually made up of around 3000!!

 

The Pleiades, or the Seven Sisters, open cluster

 

A couple of hours after Pleiades has risen the most iconic constellation will appear: the great hunter Orion, with its characteristic belt of three stars, is easy to spot. If you spot him earlier he’ll be having a little lie down!

 

Mars is nice and easy to find too! East East South you’ll see a nice orangey star, our rusty neighbour. It’s begun to move away from us as our orbits carry us away from each other, so now is a nice time to see it. Unfortunately for our lifetime its only going to be getting smaller and darker, so get out there and see it now!!

 

The other star that is incredible at the moment is our next neighbour and planetary sister, Venus, better known as the morning star. At about 06:00 in the East it will appear as an incredibly bright star! I find it a bit unnerving sometimes, as its brightness is something not a lot of people expect. But get up early and you can’t miss it. You may also see a fainter orange object just to the right. This will be Saturn, following Venus across the sky.

 

There’s plenty to see out there, so tonight and tomorrow morning get up and get out!