By Michael Carroll
Best-selling author of Ventriloquism for Dummies

Introduction     Part 1     Part 2     Part 3     Part 4     Part 5

Lesson 3 - Astronomy

For those not in the know, we live on a planet called Earth. This planet orbits a sun called "The Sun" and is, in turn, orbited by a moon called "The Moon". They're part of a solar system known as "The Solar System" which inhabits a galaxy we call "The Galaxy", one of many different galaxies that drift about in a big empty space called "Space", all part of a universe called... Well, you get the idea. Clearly, our ancestors didn't have much imagination when it came to names.

But what, exactly, is a planet?
Simply put, a planet is a large, round ball of matter, sometimes - but not always - composed of a solid crust surrounding a liquid core, sort of like a spherical version of a McDonald's Apple Pie, with the obvious exception that only a very small number of planets bear the message "Caution: Filling is Hot".

What are planets for, then?
It would be tempting to answer "for generating and supporting life", but given that there's only one planet that we're aware of that does support life (i.e., Earth), clearly that answer is not quite substantial enough.

Now, some folk believe that the universe was created specially for us by a sort of all-powerful, eternal being, but since that way of thinking will take us down a different path - the one that puts the wishy-washy word "meta" before the strong, solid and quite dependable word "physics" - we'll avoid that for this lesson.

Astrologers would have us believe that the other planets in our solar system - despite being both rather small and far away - play some part in determining our lucky colours and whether we'll find new love on Wednesdays, but most proper scientists rightly debunk such absolute rubbish as nothing more than absolute rubbish.

If Earth is the only inhabited planet, that means that all the other planets (and stars and solar systems and galaxies, and - perhaps - the other universes) are pretty much useless...

Or are they?

Well, yes they are, at the moment. We don't yet have the resources to fully exploit the other planets. Annoyingly, all the really good resources - like iron and stuff - are buried pretty deep under the surface of the Earth. Even more annoyingly, out in space there's loads of asteroids that quite probably contain lots of handy minerals that would be a lot easier to mine, if only we could get there.

Unless some other race lays claim to them - which doesn't seem likely to happen in the near future - right now the best approach is to assume that the other stars and planets are "room for expansion". As a scientist, I feel compelled to take this approach, for the only other purpose the planets serve is to help make the night sky a little prettier. Though if that turns out to be their only reason for existence, I'll be annoyed: clearly, the designer of the universe was just making it up as he went along. If it was up to me, I'd have used the space for something more profitable, like a giant cosmic billboard or - better still - a great big telly. However, since sound doesn't travel through space, it would have to be a telly that showed only silent movies, and unfortunately all silent movies were crap (if they weren't crap, why aren't they still being made?).

So why are planets round? Why aren't they, say, cuboid or pyramid-shaped?
The answer to this one has perplexed scientists for centuries, and many theories have been put forth, mostly concerning that mysterious force known as "gravity". The truth, however, is actually rather straight-forward...

You see, the Earth is about 149.5 million kilometres from the Sun, and it takes a year to complete an orbit. Assuming for the moment that the orbit is circular (it isn't, but I don't know how to calculate ellipses), that means the distance the Earth travels in a year is (2 x Pi x 149,500,000) km. Which comes to a little over 939,336,203 km. The Earth has been around for about 4.6 billion years, which means that, so far, it has travelled about 3,757,344,812,000,000,000 km.

On top of that, since the Earth travels 939,336,203 million kilometres in a year, and there's 8,760 hours in a year (24 x 365), that means that the Earth is moving at around 107,230 kilometres per hour.

Now, even though space is called "Space", it's not entirely empty; there's all sorts of cosmic rays and meteors and space dust and stuff out there. After barrelling through this mess at over 100,000 kph for 3.7 quintillion kilometres, is it any wonder that all the edges have worn down? So to sum up, planets are round because of erosion.

Are there any other planets, apart from Earth?
Yes, there are! In fact, our very own solar system contains a total of nine planets, or ten if you count Sedna, which most reputable astronomers don't. Or eight if you don't count Pluto since its recent reclassification as a "Dwarf Planet". As far as I'm concerned Pluto is still a planet - I don't remember voting on whether to change its status, do you?

There are also planets orbiting other solar systems, but they are so far away that it's not likely any of you lot will ever get to visit them, so they might as well not be there.

Our local planets, though, are a lot more attainable. So far, we haven't really put much effort in; I mean, it's been over thirty years since the last manned mission to the Moon, and what have we done since? Crashed a few probes on Mars and Venus, and sent a handful of others to photograph the outer planets. The reason for this is tragically simple; governments won't invest in space exploration until they can see a way to make a profit out of it. The sad truth is that the human race spent more money visiting the failed Planet Hollywood restaurant chain than we've spent visiting actual planets.

Now, the planets in our solar system are, in order...

Mercury
Originally called "Mar-Curie", this planet was named after the discoverer of Radium, Marie Curie. It's the planet closest to the sun, and thus is very very hot indeed. It's even hot enough to fry an egg on the bonnet of your car, even at night.

Venus
Many, many years ago it was believed - on very little evidence - that Venus was a glorious world; a paradise. This we now know to be false; with its incredible temperatures and poisonous atmosphere, far from being Heaven, the planet Venus is closer to Hell. Sadly, those dreams of paradise have turned out to be nothing more than Venus envy.

Earth
The planet on which most of us live, Earth is the only planet in the universe named after something a gardener scrapes off his boots when he comes in for a cup of tea.

Mars
The famous red planet, except that it's not really red, it's more a sort of muddy brown. Mars is, at times, the closest planet to the Earth, and with today's technology it actually is possible to send a manned mission. But... All the signs indicate that Mars is a lifeless world, so the big question is this: "Should we bother?" It's probably the most important question in astronomy right now, and I know for a fact that there are all sorts of big, serious discussions going on, even though most astronomers seem to be pretending that no such discussions are taking place. Certainly, none of the scientists I interviewed for this article were comfortable answering my questions on Mars-Debating.

Jupiter
The largest planet in our solar system, Jupiter is a great big ball of gas. There's nothing much of interest there except for the giant red spot. Known in astronomy circles as "the giant red spot", this is something of a mystery. It's quite possible that some sort of aliens live there, though not likely.

Saturn
Known as "the one with the rings", Saturn is another great big ball of gas. It'd probably be pretty cool to be on Saturn, especially when the sun dips below the rings; you'd get lots of shadows and stuff, and budgies would keep falling asleep thinking that it's night time. However, it's widely accepted among physicists that budgies would not be as useful on Saturn as canaries, which would be able to warn us if the gas was poisonous.

Uranus
It's a little-known fact that this planet doesn't actually exist; it was made up as an excuse to use a rude-sounding name. In light of that, it's interesting to note that some wet-blankety astronomers insist that the correct pronunciation is "Your-annus", and not "yer-anus".

Neptune
Another imaginary planet, invented by infuriated atheist astronomers in 1846 in order to scupper astrologers, on the grounds that if our destinies really are influenced by the positions of the planets, then the astrologers would have to completely recalculate everything if a new planet was "discovered". Luckily, the astrologers correctly predicted that the astronomers would do exactly this, and developed a get-out-of-jail-free scheme; from that point on, they included such handy ambiguous phrases as "may" and "might" into their prognostications.

Pluto
This, the outer-most planet in our Solar System, was discovered in 1930 (can it be a coincidence that this is the very same year that Walt Disney introduced his legendary cartoon character? I think not!) Pluto is so far away from Earth that it's completely frozen, which would of course make it an ideal location for a snow-boarding holiday. Sadly, the most recent scientific papers on Pluto suggest that the distance is so great that all of the snow-boarders' holiday time would be spent travelling.

Summary:
So that's astronomy, then. If you find the subject intriguing, you might like to invest great wodges of cash in an expensive telescope, which you can point at the night sky to see the tiny dots of light as slightly larger dots of light.