Science in the Skies
Remember the sky is dynamic and ever changing! As the Earth orbits the sun most stars move round sky through the course of the night, and throughout the course of the year too.
So, what’s up there?
The Moon
The moon is the second brightest visible object in the sky after the sun, and is the closest celestial object to Earth. At an average of 238,855 miles away, it would take you about 9 years to walk there without stopping. The moon’s rotation is in unison with that of the Earths, and this results in the same side of the moon always facing the Earth. The moons prominence in the sky and its regular cycle of phases have made the moon an important cultural influence since ancient times. The moon’s influence is found in language, calendars, art, and mythology. A moonlit night may not be so good for stargazing but makes for an excellent opportunity for activities like walking or trail running, a superb back drop for storytelling and an inspiration for night time photographers.
Lunar Eclipse
There is something utterly awe inspiring about seeing an eclipse and humankind has been captivated by them since the beginning of time. A total lunar eclipse can be seen approximately every 2.5 years, with 3 or so other partial eclipses happening each year. During a total lunar eclipse, the sun, Earth and moon form a straight line. The Earth blocks any direct sunlight from reaching the moon. The Sun is behind the Earth, so the Sun's light casts the Earth's shadow on the moon. This shadow covers the entire moon and causes a total lunar eclipse. In 2015 there were the eerie ‘blood moons’ during eclipses. See time and date predictions of next total lunar eclipses.
Comets
There are several hundred comets that spend most of their lives among the planets of the inner Solar System. Some comets are likened to "dirty snowballs", being made up of a mixture of dust and volatile ices such as water, carbon dioxide, and ammonia. Comets leave trails of burning gas and dust behind them leaving the classic comet tail.
Comets are quite rare and roughly one comet per year is visible to the naked eye. Particularly bright examples are called "Great Comets” the most famous one being Halley. Halley is the only naked-eye comet that might appear twice in a human lifetime. Halley last appeared in the inner parts of the Solar System in 1986 and will next swing by earth in mid 2061.
Meteors / Shooting Stars
So, what is behind the magic of a shooting star? As particles of dust fall through the Earth’s atmosphere, they are seen as streaks of light across the sky as 'shooting stars'. At certain times of year, as the Earth passes through clouds of space dust, there will be amazing meteor showers and as many as 100 shooting stars may be seen in an hour! The most visible ones happen in August, October and December. As if especially for Wales, October’s Draconid meteor shower radiates from the fiery mouth of the northern constellation Draco the Dragon and fills the night sky with a fantastic display.
Planets
We have eight planets in our Solar System. They look like stars in the night sky, with five being bright enough to be seen with the naked eye. Obvious planets to look for are Venus –very bright especially after dusk and before dawn, and Mars which can be distinguished by its reddish colour. The matter of life on other planets is a fascination for astronomers and lay people alike, and as you look up consider if too there is someone or something looking down at you!
Stars
Stars are balls of gas that emit heat and light as they undergo intense nuclear fusion process. The sun is the nearest star to Earth at about 93 million miles away. The next nearest, Proxima Centauri, is a mind blowing 271,000 times further away. There are lots of different types of stars with all sorts of interesting names, the most common ones in the Milky Way being ‘Red Dwarfs’.
Northern Lights
The Northern Lights , also known as Aurora Borealis can be seen from all parts of Wales, though more likely in Snowdonia and in the winter. The darker the skies, the better the chances of seeing this phenomenon. The lights depend on solar activity that varies on an approximate 11-year cycle with 2013 being a recent peak, the next one being due in 2024.
As the Northern Lights are unpredictable, the best way to find out about them is to sign up for forecasts (1-3 days) or alerts (1 hour).
Aurora Watch UK website (and Facebook page)
Constellations
Constellations are groups of stars in the sky that form patterns. There are 88 officially recognized constellations. 36 of these are located in the northern hemisphere of the sky while the remaining 52 are in the southern hemisphere.
Throughout history humankind’s imagination has been ignited by the stars and the patterns they form have been described as animals, objects and mythological characters. Whilst in Wales go on a dragon hunt and find the Draco constellation with its fire breathing head and long snaking tail! Many of the Constellations in the Welsh language and culture have unique names that link them to the landscape, mythology and culture of Wales.
Constellations are groups of stars in the sky that form patterns. There are 88 officially recognized constellations. 36 of these are located in the northern hemisphere of the sky while the remaining 52 are in the southern hemisphere.
Galaxy
A galaxy is a collection of stars, gas and dust that are bound together by gravity. Astronomers think that there are hundreds of billions of galaxies in the universe, however the exact number is not known
Here on Earth we are part of a galaxy called the Milky Way. The Milky Way is a dynamic spiral galaxy. It has a bright central core with a high density of stars, and then a flattened disk surrounding it – like a spinning record. Two spiral arms start just outside the core, and then spiral outward like a pinwheel to the outer edges of the galaxy. The Milky Way measures about 100,000 to 120,000 light-years across, and is thought to contain 200-400 billion stars (best scientific approximation to date).
International Space Station and Satellite passes
Passes of the International Space station (ISS) overhead are a spectacular sight at night or dusk. The very fast bright moving object takes about one minute to cross the sky. It can be easily seen with the naked eye. The ISS looks like a plane flying very high, and will be an arc of intense light. Its predictability means it can be watched out for with precision timing. If the timings are right on a Christmas Eve the ISS can easily be mistaken for Santa’s sleigh!