You know which word I hate? And by “hate” I mean loathe, with a fist-clenching passion? “Amazing“. Everything is ‘amazing’ nowadays, the word has to be the most over-used in the whole of the English language. It’s ******* everywhere. Judges on TV ‘talent’ shows describe even the most average performance as “amazing’; new flavoured crisps are “amazing”; TV news reporters describe everything from floods to sleepy sheep as ‘amazing’. Like other words, such as ‘hero’ and ‘beautiful’, it’s lost its power, its true meaning. ‘Amazing’ now just means… interesting. Cool. Ish.
But the other day a story broke in the world of astronomy which is amazing in the original, true, jaw-hit-the-floor “WOW!!!!!” sense of the word. And ‘amazing’ is really the only way to describe it.
Everyone with even a passing interest in astronomy – from the loner kid reading books in the library at breaktime when they should be outside playing football (yes, that was me…) to the world-weary astrophysics professor sat in a university somewhere – knows that the closest star to the Earth, after the Sun, is Alpha Centauri, a bright, naked eye star in the southern hemisphere, close to the famous Southern Cross (see above image, one of astrophotographer Akira Fuji’s beautiful night sky portraits). That’s just one of those basic, fundamental facts. And until this week, everyone with even a passing interest in astronomy knew that Alpha Centauri was only interesting because it was close, and not for any other reason, right?
Well, now we know Alpha Centauri isn’t just the boring, average neighbouring star system we thought it was. Now, after believing for years that it was planetless, we know that it has at least one planet orbiting i. And even though that world is nothing like Earth, not really, that’s not the point. The point is that the closest star to the Sun HAS A PLANET GOING AROUND IT!
And even better, the planet in question is a small one, not one of those pretend, bloated, gassy “super” or “hot Jupiters” that so many stars have ploughing or trawling through their outer atmospheres: it has the same mass as Earth, roughly, which is fantastic! BUT… and yes, there’s a “but”… like those blasted “hot Jupiters” it orbits Alpha Centauri B very closely and very quickly: it orbits the star at a distance of just 6m km (closer than Mercury orbits the Sun in our solar system), racing around it like a car on a race track, and its year is just 3.2 Earth days long. So if it’s rocky its surface isn’t covered in lakes, green fields and lush forests, it’s probably molten and scorched, the closest thing to hell you can imagine. So, life? Not very likely.
BUT THAT’S NOT THE POINT!!!!
After years of thinking that only distant, faraway suns have planets orbiting them, suns so faraweay they might as well be in another galaxy entirely, it turns out that the closest exo-planet is, in astronomical terms, just next door.
Ah, but the key phrase there is “in astronomical terms”. Make no mistake, this is a genuinely amazing thing. To have an exoplanet so close, so tantalisingly near (again, in astronomical terms) is an incredible thing. It brings the whole field of extrasolar planetary science so much closer to us. But the distance thing is seriously mindblowing, and it’s something the popular press just hasn’t grasped yet. They seem to think that Alpha Centauri is just beyond the solar system, a short hop out into deep space.
Er, no. It’s a long, long, loooooong way away.
Well, the easy, pub quiz answer is “4.3 Light years” of course, but just how far IS that, really? In kilometres or miles? Naaah, that still doesn’t help. Those are silly numbers. Lots of zeroes, doesn’t help at all. What we need is something we can see, and hold, a prop to SHOW us how far away the Alpha Centauri system is, right? And luckily, I ‘ve found just the thing…
Yep, a humble CD. Look over there, by the TV, you’ve got stacks of them. Look there, next to your computer, you’ve got loads of the things. Turns out they’re perfect for showing just how far away Alpha Centauri is. So, grab one, and prepare to have your eyes opened, and your hopes of hopping over to our nearest extrasolar planet well and truly dashed.
Right, take a look at your CD. We’re going to pretend that’s our solar system, with the Sun at the very centre of the disc – in the middle of the hole – and Pluto at the very edge of the disc (yes, I KNOW it’s officially not a planet anymore, I’m not getting into all that again; I’m just using Pluto as a ‘boundary’ everyone can relate to, ok? Sheesh!! :-) ) On that scale, Alpha Centauri would be 0.4km away – or 3,333 CDs away…!
That should bring home just how far away Alpha Centauri’s planet is. But what helps even more is to use our CD as a different scale. Look at your CD again, and this time instead of imagining the rim as Pluto, imagine it as Earth. Using that scale, Alpha Centauri would be 16.5km (10 miles) away… or more than a hundred and thirty three THOUSAND CDs away…
So, now you can see that Alpha Centauri is not, despite what the popular press are saying, “close to us in space”. It’s a helluva long way away. In fact, if you were to set off for it in a fast spacecraft, going the same speed Apollo 11 travelled at going to the Moon, it would take you 116 THOUSAND YEARS to get there. (However, at the moment we’ve nothing that CAN go that fast, so that figure’s a bit depressing for more than one reason…)
But listen, don’t get too fixated on the whole distance thing. Just accept that it’s a long way away, we can’t get there now, and might not get there for centuries, or longer. That’s not the point. The point is, it’s yet another piece of proof that planets are common in the universe, and that’s a good thing. Because the more planets there are Out There, the better the chances are of life – advanced or otherwise – existing Out There too. It really is as simple and as exciting as that.
See? Told you it was amazing! :-)
If you want some of the real, serious science behind this story, I strongly suggest you go over to UNIVERSE TODAY and read Nancy Atkinson’s write-up of the discovery. In it she’ll tell you more about the people who made the discovery and the equipment they used, and explain why it’s such an important scientific milestone. Reading the comments after her article is interesting too, and shows how discoveries such as this generate a really wide range of reactions, from the breathlessly-excited “OMG! OMG!” to the sober and cautious “Let’s all just calm down, shall we?” Inbetween there are the inevitable “What use is this discovery to me?” party poopers and even people who think it’s all just made up. Fascinating. But warning: if you get upset reading comments posted by trolls, you’d better have a stress ball handy to squeeze and pummel half to death if you read comments on UT stories, because there’s at least one guy there who seems to have made it his sacred mission in life to haughtily disagree with everything Nancy says, and argue with many other comment posters, too. I honestly think that if Nancy wrote “Milk is white” he would disagree. I can’t be the only UT reader wishing his computer would just blow up…! ;-)
One last thing I want to say about this incredible discovery. It really, REALLY is time we started giving exoplanets proper names, and not just christening them “b”, “c” and “d” etc. It’s getting bloody silly. To call the closest exoplanet to Earth “Alpha Centauri Bb” is ludicrous and demeaning, both to the planet and its discoverers. It deserves a proper name! Come on! When craters, hills, even individual rocks on Mars, the Moon and even asteroids have been given names, what the hell is stopping us – and by “us” I guess I mean the Astronomical Powers That Be – from naming exoplanets? Ok, in the centuries to come they’ll be given names by the people who travel to and settle on them, but we can at least give them provisional names now, if only so we all know which planet we’re talking about? It would make things so much easier, wouldn’t it?
I even have a suggestion – “Glenstorm”, one of the centaurs from the Narnia books of CS Lewis. In Narnian mythology, centaurs were wise and clever, philosophers, prophets and stargazers – much less bloodthirsty and crazy than Greek centaurs who were just nuts – so I think it would be very fitting to name a planet, found orbiting Alpha Centauri, after a stargazing centaur. That way, whenever we looked up at the stars of Centaurus, shining there amidst the starclouds of the southern Milky Way, we’d think of the planet and, in our imaginations, see something like this…
…and maybe not something like this…
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