I have always had an interest in astronomy and the cosmos. However, within the last year and a half this passion has grown exponentially. Interestingly, it was a handful of mind-blowing facts that catalysed and nurtured my curiosity. One of these was related to the star Betelgeuse (A.K.A Beetlejuice), which is the star that makes up Orion’s left shoulder. This star is 497.9 light years away (this means the light we see today left Betelgeuse when Henry VIII was on the throne of England) and is a red giant star, which means it is towards the end of its life-cycle. This star is big. Incredibly, mind-blowingly big. If Betelgeuse was to magically swap places with the star at the centre of our solar system (the sun), it would completely annihilate Mercury, Venus, Earth, Mars and it is likely it would reach the orbit of Jupiter. To put this into context, Jupiter is currently 778,500,000 km from the sun. The estimated diameter of Betelgeuse is 1,641,380,000 km! In addition to its epic size, Betelgeuse will also ‘go supernova’ (a stellar explosion whereby a star expels most/all of its materia) within the next 1,000,000 years or so. Sadly, it is unlikely that humans will still be around when this happens, but boy would it be a spectacle. You would be able to see it from earth with the same level of brightness as the full moon; it would be visible during the day!

Orion is an amazing constellation; it is easy to find and contains a wealth of astronomical charms. Indeed, Orion’s swords, or dagger, is known as the Great Orion Nebula (GON; a nebula is a gigantic interstellar cloud of dust, hydrogen, helium and other ionized gases- the birth place of new stars). The GON is just about visible to the naked eye under clear skies (easily visible with even a small pair of binoculars) and is c.1344 light years away (the Anglo-Saxons inhabited Briton when the light we see today left the nebula). The radius of this colossal cloud of gas is a staggering 12 light years (or 113500000000000 km!).

All of the stars that we can see with the naked eye or telescopes are in our galaxy the Milky Way. The Milky Way contains around 400 billion stars and as many planets. The observable universe contains between 100-200 billion other galaxies, each one consisting of hundreds of billions stars. The other fact that caught me hook, line and sinker relates to the Andromeda galaxy (or M31, relating to its ‘Messier’ catalogue number). Andromeda is the Milky Way’s nearest spiral-galaxy neighbour. As with so many things relating to the cosmos, it is gigantic. At its widest point it is 141,000 light years in diameter (or 1,333,934,510,000,000,000 km) and it contains over one trillion stars; at least double the number of stars than the Milky Way. Andromeda is so large that it appears as a smudgy, white cloud to the naked eye (under dark skies) and even more so with a pair of small binoculars or a telescope. Now we get to the cool stuff. The Andromeda galaxy is 2.5 million light years away. This means the light that hits our retinas today left its source before Homo erectus, an early hominid, had even evolved; humans were a long way off entering the scene. You are literally looking back in time every time you look up to the heavens. And the fact you can see these sights with your naked eye or a cheap pair of binoculars blows my mind.

Unlike a large percentage of the other galaxies in the universe that are flying away from us at colossal speeds (because the universe is expanding), Andromeda is flying directly towards us at 110 km a second. It has been mathematically predicted that Andromeda will smash into the Milky Way in 3.75 million years. Again, this will not affect humans because we will definitely be extinct (our sun would have expanded so much that liquid water could no longer exist on Earth), but it would be a most beautiful event, as shown in this model (GIF). Unfortunately, Orion and the Andromeda galaxy are now setting very early in the evening, so we will have to wait until around late November to see them again. But there are plenty of other fantastic sites above, so don’t you worry.

As a number of you may be aware, I was recently gifted a 130 mm Newtonian reflector telescope [2]. This was a massive upgrade from my 7×50 binoculars and boy have I been enjoying it. Jupiter was my first target. The largest planet in the solar system and the father to over 60 moons, four of which (the Jovian moons, in order of distance from Jupiter= Io, Europa, Ganymede and Callisto) are easily visible from earth with a pair of binoculars. Ganymede is the largest moon in the solar system and twice the mass of our moon. The composite image below shows the relative sizes of Jupiter’s largest four moons as well as some beautiful surface detail.

When seen through a small telescope it is clear to see Jupiter as a large, bright disk, with the four large moons appearing as very bright stars. And if you are really lucky, and the atmosphere is nice and calm[1], two dark red bands will suddenly jump out at you from the surface of Jupiter. It really is an awesome experience seeing this for the first time. When seen with the naked eye, Jupiter just looks like a very bright star; indeed, this is probably what most people think it is. But even using modest equipment you can see this is not true…it is another world; a giant, majestic planet and the king of our solar system. Depending on the time of year, the distance to Jupiter from earth ranges between 588 to 968 million kilometres. This means the light we see through our telescopes left Jupiter between 32 and 54 minutes ago.

My next target was Saturn; the jewel of our solar system. I can distinctly remember the first time I saw Saturn with my own eyes. It really is an incredible moment. It makes you realise that the giant ball of gas and bright rings of ice is actually out there up in the sky. It may appear as a golden star to the unaided eye, but even a small telescope can resolve its rings. It is all well and good seeing the awesome pictures from the Hubble telescope and the Cassini satellite, but seeing it with your own eyes is something special. In fact, when Kerrie saw it for the first time at the Auckland Observatory, NZ, she did not think it was real; she thought somebody had put a mini picture at the end of the scope. If you have not already looked at Saturn with your own eyes, do it as soon as you can, and this is the perfect time of year for it. Look up your nearest astronomy club or ask a friend who has a telescope (I am more than willing to show anybody who is interested)- you will not be disappointed. When you are looking at Saturn you are observing details on a planet that is 1.3 billion km away. Its rings have a diameter of 364,900 km, which is around the same distance from our moon to earth and it would take light just over a second to travel the distance from one edge to the other. Saturn really is an incredible planet.

I don’t think this post would be complete without a picture of Saturn as seen through the Hubble Space Telescope, so see below. I know, I know, it is a little bit better than my image. That is because Hubble has a 2400 mm mirror, compared to my 130 mm mirror. Oh, and my telescope is not orbiting above the atmosphere at 560 km above sea level, I suppose that helps, too (I also think the Hubble camera is a bit better than a wobbling 5 mega-pixel smartphone, but I may be wrong). The photo below shows Saturn’s equivalent of our Northern Lights, a visual display caused by the sun’s solar energy interacting with Saturn’s atmosphere.

It does not take much fancy equipment to become awestruck by the night sky. So grab a pair of binoculars and head out to a nice dark sky away from the city; you will not be disappointed. Even the moon, the object that most of us take for granted, gives us some beautiful sights. You can see a fair amount of craters and terrestrial detail on the moon even with your naked eyes! Away from the horribly light-polluted city sky there is a whole new world waiting for you to discover.

Footnotes:

[1] The atmosphere protects us and allows life to evolve and thrive on planet earth. However, to amateur astronomers it is a bugger. It is continually boiling and churning away above our heads, distorting the lovely images through our telescopes (think of the shimmering air above a hot car engine or a cement car park on a hot day). Indeed, it is the atmosphere that makes stars appear to twinkle in the night sky. The photons of light from these distant stars are so weak and feeble that they get bounced around and bullied by our atmosphere (when stars are viewed from the ISS or outer space, they do not twinkle at all; they appear as constant points of light). Consequently, we see very twinkling stars and on hot, turbulent summer evenings. Planets do not twinkle. The light reflected back from these close neighbours is tough and powerful. Thus it simply ploughs through our atmosphere unaltered. If you see a bright ‘star’ in the sky that does not twinkle, it is most likely a planet.

Allow one more digression. Planets do not twinkle and they always appear on the elliptic. What is the elliptic, I hear you ask? It is an imaginary line across the sky that the sun, planets and moon appear to move across. It runs from the East to the West; the planets move across the sky in the exact same way that the sun does! So if you think you see a bright star that does not appear to twinkle and it is wildly to the North or South, it cannot possibly be a planet. So there you have it. You will now always be able to identify the planets with your naked eye. I will now give some tips to identifying some of the planets with your naked eye. Venus is closer to the sun than earth, this means that it will always be relatively close to the sun. In other words, we will only see Venus at sunset or sunrise. Venus appears as a very bright star (it is in fact known as the evening or morning star) in the West and just after sunset (or in the East before sunrise, depending on the time of year). Mars is an easy one to spot with the naked eye due to its red appearance. Saturn appears as a faint golden/yellow star. I left Jupiter to last because it is more difficult to identify with the naked eye, so if it does not look like any of the others, it is most likely Jupiter, which appears as a very bright, white star. Unfortunately, Uranus and Neptune are not possible to see with a naked eye (unless you have perfect vision and very, very dark skies), but they are, on average 2.88 and 4.44 billion kilometres away, respectively.

[2] Model: Celestron Astromaster 130 mm MD EQ This entry level telescope is great for budding astronomers. I have been able to see a lots of objects in the sky including the moon, planets, globular clusters, open clusters, binary star systems, and other galaxies. This scope comes with an equatorial mount, which is very important. This design allows the mount to counter the spinning of the earth on its axis. Without this, planets and stars fly across the eyepiece in a number of seconds; you can literally observe the earth spinning on its axis! If you have any questions about the telescope, just comment here.