Newbury Weeky News monthly column

Every month, our Vice Chair Tony Hersh writes a popular column for the Newbury Weekly News. From now on, these can be found on this page and also within the pages of Pegasus, the new society newsletter

APRIL 2024

March is a great time to spot Ursa Major (sometimes also called The Great Bear, The Plough, The Big Dipper or The Saucepan) the ‘right way up’ if you look overhead at night.   It’s a constellation that is visible from the UK throughout the whole year although it changes it’s orientation gradually month by month.   The middle star in the handle part of the Saucepan is actually two stars very close to each other, Alcor and Mizar.   These two stars used to be a test of how good your eyesight was ; if you can see two stars rather than one blob of light your eyesight is very good !    Once you can spot Ursa Major you can use it to spot other constellations.   For example following an imaginary line that connects the last two stars in the saucepan downwards leads to the constellation of Leo with its characteristic backwards question mark shape in the sky.   Planets to spot this month include Jupiter, which will be just below the Moon at 1am on 14th March. If you have a small telescope look between the Moon and Jupiter at that time to find the blue disk which is Uranus. 

Topic of The Month

Space junk consists of bits of old rocket, parts of defunct satellites, even pieces of paint and frozen fuel.   In low Earth orbit these pieces are travelling around 25,000 mph so if even small pieces of junk hit something they can do substantial damage and create more junk in the process.  Newer satellites are designed to burn up in our atmosphere, go into a parking orbit or fall into the sea at the end of their useful life but older satellites weren’t designed with this capability and so might continue to orbit and gradually disintegrate over tens of years.   Ontop of that, testing of anti satellite missiles has created tens of thousands of pieces of junk larger than 10cm and hundreds of millions of smaller pieces. These form a ‘cloud’ of debris around Earth in exactly the same orbital position desired for new satellites or space stations, making putting new satellites into orbit increasingly difficult. Larger pieces of junk can be hit by other debris, destabilising their orbit and causing them to crash to Earth in uncontrolled ways, potentially causing damage or even death on Earth if they are big enough to get through the atmosphere without completely burning up.  In 1977 a Soviet satellite crashed in Canada.  It was powered by a small nuclear reactor and the Canadians received £2 million from the Soviets for the clean up operation.  More recently, in 2022, large pieces of a spacecraft, thought to be China’s defunct Long March 5B rocket crashed near villages in Borneo though luckily no one was reported injured.  Of course the Earth’s surface is mostly water so there is a smaller chance of space junk directly hitting a populated area but the amount of junk in orbit is causing big concerns for the continuity of GPS and communication satellites and no one has figured out a way to clean up space from all this waste.

FEBRUARY 2024

This month you have the best chance of seeing a small part of the Milky Way Galaxy.  This is the Galaxy we are part of that consists of at least 100 billion stars arranged in a massive spiral shape.  From our position in the Galaxy these stars appear as a faint band of light high in the night sky with the W or M shape of the Constellation of Cassiopeia right in the middle of it. You can find Cassiopeia by following an imaginary line downwards from the two stars at the end of Ursa Major (the famous saucepan shape).  Something else to look out for is the Constellation of Leo the Lion with its famous backward question mark.  Follow the two stars at the end of the Plough’s saucepan upwards and it should be easy to find.  Leo was one of the earliest recognized constellations, with archaeological evidence of it in 4000 BC.  In Greek mythology, Leo was the Nemean Lion which was killed by Heracles (Hercules to the Romans) during the first of his twelve labours. The Nemean Lion would take women hostages to its lair in a cave, luring warriors from nearby towns to their deaths trying to save the damsels in distress.  The Lion was impervious to any weaponry so Hercules defeated the Lion with his bare hands.  Zeus commemorated the achievement by placing the Lion in the sky for the rest of time.  Planets to look out for this month include Venus in the morning sky.  It will be just to the left of a crescent Moon around 7am on 6th February.  Jupiter dominates the evening sky, easily spottable just below the Moon around 6pm on 15th February.

Topic of The Month

It’s a huge puzzle to astronomers and physicists why we exist, in fact why any matter exists !  In the fraction of a second after the Big Bang, when the Universe was created, all our understanding of physics tells us that absolutely equal amounts of both matter and it’s opposite, antimatter, should have been created from the energy present.  It’s something predicted by Einstein’s famous E=mc2 equation which seems to work fine for all other measurements we make.  But if the prediction was right, over the millennia we would expect these particles to meet each other and reunite releasing energy again and reducing the amount of matter and antimatter in the Universe.  Not only are we not seeing this but there seems to be much more matter in existence than antimatter.  We can detect antimatter, but the amount we can find is vastly outnumbered by matter.  Nature seems to have a preference for matter rather than antimatter.  This strange preference has been observed on Earth in particle accelerators where smashing particles together produces, completely unexpectedly, more matter than antimatter.  It might mean some of our fundamental understanding of astronomy and physics is wrong or that something else is happening which we can’t explain yet.  It’s a fascinating if frustrating observation!

JANUARY 2024

This month spectacular Ursa Major (the “saucepan” or “plough” shape) stands vertically above the horizon in the North. Follow an imaginary line joining the two stars at the end of the saucepan shape downwards and the next brightest star is Polaris, the pole star.  This variable star (it changes its brightness over a period of 4 days) is about 433 light years away, is visible all year round and it’s position in the sky is such that it always points towards magnetic north and is a useful marker if you’re lost at night !   Near the highest point above your head is another bright star called Capella, the fourth brightest star in our northern hemisphere after Sirius, Arcturus and Vega and part of a constellation called Auriga.  It’s only about 43 light years away and is one of the strongest sources of x rays in the night sky.  Although it appears to be a single star to the naked eye, Capella is actually a quadruple star system organized in two binary pairs.  Keep a look out for meteors during the first 12 days of January when the Moon is only a crescent, because the Quadrantid meteor shower that started late in December continues.  Look in the direction of Ursa Major about half way up the sky after midnight and you might see a meteor every few minutes. The peak happens around the 3rd January.  Regarding planets Venus is bright this month in the mornings and can be seen just above and to the left of the crescent Moon at about 7am on 8th January.   Saturn is shining in the evening sky.  An easy time to spot it will be around 5pm on 14th January when it will be just to the right of a beautiful thin crescent Moon and well worth a look if it’s clear.

Topic of The Month - Red Dwarfs

We tend to think we can see millions of stars in a dark clear night sky but in fact, unaided, even people with exceptional vision can only see at most 10,000 stars in a perfectly dark sky.  There are many, many more stars we can’t see without magnification. In fact of the sixty nearest stars to Earth fifty are too dim for the unaided eye. These are red dwarf stars, the most common type of star in the universe, which glow a dull red and far less brightly than bigger stars.  Red dwarf stars form just like other stars out of a molecular cloud of dust and gas.  Gravity pulls the swirling gas and dust together, and it begins to rotate. The material clumps in the centre, and when it reaches a critical temperature, fusion begins. However red dwarfs have very low mass compared to brighter stars. As a result, they have relatively low gravity crushing material down, a low nuclear fusion rate, and hence, a low temperature and so they emit relatively little light.  Even the largest red dwarfs have only about 10% of the Sun's luminosity. Their low rate of nuclear fusion means they use up their fuel much slower than brighter stars and some are thought to have existed since the beginning of time, 13.8 billion years ago, far longer than other brighter stars. Because of their longevity and constant heat output astronomers are interested in the many planets which can orbit red dwarfs because these planets will have had constant conditions for far longer than Earth. If these planets have the right conditions for life to have evolved, like liquid water, they might be more likely to support life simply because of the duration of the constant conditions.

DECEMBER 2023

In the winter the northern hemisphere of Earth is tilted away from the Sun (which is why it is colder) and towards the Moon (so the Moon is highest in the sky and brighter).  The famous Geminid meteor shower is definitely worth a look on the nights of 14th and 15th December in the south around midnight originating above the Constellation of Orion.  The Moon is about half lit on these nights so won’t disrupt viewing too much.    Often these meteors are bright and relatively slow moving across the sky and we can expect to see perhaps one every few minutes if we are lucky.  Have a look at Betelgeuse, the reddish star in the top left shoulder of Orion.   This star is a red giant 650 light years from Earth that dimmed suddenly last year making some Astronomers believe it was about to explode (go supernova).   If it did it would suddenly be visible day and night before fading away and it is certainly tipped as one of the most likely nearby stars to explode.  However, very recent data shows that changes have slowed and the dimming may be caused by a massive release of dust into the star’s atmosphere rather than its imminent explosion.  

Regarding planets Saturn will be visible just to the right of the Moon on 18th December and Jupiter can be spotted just to the right of the Moon around 5pm on 22nd of December.

Topic of The Month

Astronomers are adding knowledge to the question of how life started on Earth.   A popular theory is that meteorites hitting Earth had a role because they have been shown previously to contain water and a variety of chemicals needed for life.   However the problem until recently had been that the composition of meteorites which had previously landed on Earth might have been contaminated from the interaction of meteors with the Earth’s atmosphere or from the surface of Earth.  A report was published recently of a sample of a distant asteroid taken by Japan’s Hayabusa2 spacecraft which was delivered to Earth in a sealed capsule so we can be sure it wasn’t contaminated.  Analysis found that asteroid contained a surprising range of different chemicals and biologically important molecules including a variety of amino acids, amines and carboxylic acids which are found in proteins, vitamin B3 and Uracil, one of the four key nucleobases.   Nucleobases are nitrogen containing compounds that make up RNA, which is a molecule present in all living cells and is similar to DNA.   What is extraordinary is that so many complicated molecules had formed on the surface of the asteroid which is exposed to the terrifically cold and high radiation environment of space.  It seems quite possible given the vast numbers of pieces of asteroids and meteors hitting planets over billions of years that some will hit planets like Earth which have conditions to take these molecules and use them in the development of life.   It might also mean that life on other planets could be similar to life on Earth if they developed from a similar starting point.