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So, what have they ACTUALLY found around that star..?

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…and so last night, 6pm UK time, the Big News was finally revealed to the world (or at least to those people who hadn’t already figured it out for themselves, or heard or read about it, because, as usually happens, the Big Secret leaked out long before the press conference): international (not just from NASA or the US) teams of astronomers, using telescopes in space and on the ground, had detected a total of seven planets orbiting a star far, far out in space…

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– and as if that wasn’t cool enough (and it would have been pretty cool to have found a whole alien SOLAR SYSTEM!!!), all the planets are roughly the same size as Earth, and the icing on the cake was that several of them orbit within the star’s “habitable zone”, meaning they might, MIGHT have water  on their surfaces and if that’s true then they might, MIGHT have conditions suitable for life to exist on them too –

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– cue the internet going into meltdown, as wild speculation about their alien inhabitants began, fuelled by the gorgeous “space art” artwork released by the science teams showing artists’ impressions of the planets, showing spectacularly beautiful alien landscapes, complete with wave-lapped oceans and sci-fi skies crowded with more planets than the opening titles of Blake’s 7…

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Today the popular media picked up this story by the neck, shook it until it could hardly breathe and then went on a feeding frenzy of speculation and hype. The worlds were “like Earth!” and “might have life!” The star was “so close that we might visit it in future”. Etc , etc.

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Let’s just calm down, and take a look at what’s actually been found, and how significant all this really us.

Firstly  – where are these new planets?

Well, they are in orbit around a star which is now being referred to as “TRAPPIST 1” after the telescopes that detected the worlds. If you think that’s a poor name for such an important star, then consider this: it’s full official name is “2 MASS J230629280502285”. Yeah, suddenly “TRAPPIST 1” doesn’t seem so bad, does it?

TRAPPIST 1 lies in the constellation of Aquarius, one of the zodiacal constellations, but it’s hard to see at the moment because the Sun’s in the way…

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Actually, even if the Sun wasn’t in the way you’d need a telescope the size of a small cannon to see TRAPPIST 1 because it shines – if that’s the right word – at a lowly magnitude 18.8. That’s ridiculously faint. In contrast, Pluto is a blazing beacon with a magnitude of 13.5 at its brightest…

TRAPPIST 1 is so faint for a number of reasons, but mainly because it’s a very small, very feeble star that is a long way from us. I know a lot of the popular media have been saying it’s “only 39 light years away”, and 39 sounds like a small number when you compare it to star clusters which are thousands of light years away and galaxies which are tens of millions of light years away, but 39 light years is hardly next door in cosmic terms. That still makes it over 226 TRILLION miles away. To put it another way, that’s so far away that the fastest spacecraft ever built – the New Horizons probe which travelled to Pluto – would take 800 THOUSAND years to reach it, and Tim Peake, travelling in the  Soyuz capsule which carried him up to the International Space Station, would have to travel for 1.5 MILLION years before reaching it…

So, it’s close in astronomical terms, but realistically it might as well be in another galaxy entirely, it’s so far away.

But TRAPPIST 1 isn’t just far away, it’s small too. If you think of the Sun as a basketball, then TRAPPIST 1 would be a golf ball beside it. It’s a red dwarf star – but not just your typical run-of-the-mill red dwarf; it’s what’s known as an “ultra-cool dwarf star”, with a surface temperature just over 2000 degrees K, making it much cooler than our own Sun. So, to sumarise, this now-famous star is not just far away, small, and cool.

But in a way that’s a good thing – no, it’s a GREAT thing, because there are HUGE numbers of stars just like it, small cool stars, “out there” in our galaxy and beyond, and although we have always thought them unlikely to have any planets, the fact that we’ve now discovered a whole solar system around one of them suggests that others might… will… have, too. So, with the discovery of a family of worlds around TRAPPIST 1 astronomers suddenly find themselves looking up at a whole new sky – a sky where even the feeble, fluttering candle flame stars we thought would be barren have families of planets waiting to be found and studied. And that alone makes this discovery history-making.

But of course the planets are the stars of the show – if you see what I mean – and we now know that 7 worlds whirl around TRAPPIST 1. And not just any worlds – worlds roughly the same size as our own. Or, to give them their proper classification: “Earth-sized planets”.

Now, this is a good time to make a very, VERY important point. The hunters of exo-planets are very – some say far too – fond of flinging around the term “Earth-like” when describing planets found around other stars that share some but not all characteristics with Earth, but for all the reasons given in my previous blog post they really need to stop doing that. Thankfully the term “Earth-like” was hardly used at all during yesterday’s press event, but in the all-you-can-eat-media-hype-buffet that followed, some of the planets found around TRAPPIST 1 were incorrectly described as “Earth like” by reporters who had picked up on the use of the words “water” and “habitable”, and, adding 2 and 2 to get 50, told their readers, viewers and listeners that astronomers had found planets “like Earth” around TRAPPIST 1. So, let’s get this perfectly straight.

  • Astronomers have found 7 planets in orbit around the star TRAPPIST 1.
  • All these planets seem to be roughly the same size as Earth. That makes them “Earth-sized”.
  • Three of the planets are in the star’s “Habitable Zone” – the area around the star where temperatures are mild enough to allow water to exist on the surface of a planet or body orbiting it at that distance. This does not mean they definitely HAVE water, just that it’s scientifically possible.
  • The people describing these worlds as “Earth-like” are wrong. Just because a planet roughly the same size as Earth is found in a star’s habitable zone, it doesn’t qualify as “Earth-like” and should not be described as such by anyone. By this very broad definition both Venus and Mars are “Earth-like” but as everyone knows Mars is a frozen desert world and Venus is an acidic hell hole, so just because as planet is the right size and in the right place it doesn’t qualify as “Earth-like”.
  • Yes, the three planets found in the star’s habitable zone are among the most promising candidates for having life that we’ve found to date, but again, there is absolutely no proof of this, it’s just scientifically possible, that’s all.
  • …and even if they do have life, that doesn’t mean they’re inhabited by living, thinking, spaceship-building, radio telescope-operating alien beings. “Life” could just be very primitive – grey lichen flakes coating the sides of rocks, extraterrestrial snotty slime dripping and dribbling down subterranean cave walls, or even just microscopic bacteria beneath or even inside the stones. That would disappoint the SF crowd, with their long-cherished dreams of shaking tentacles or at lease becoming pen pals with ETs from another star, but in purely scientific terms it would be unbelievably pant-wettingly exciting. The discovery of ANY life, however simple, ANYWHERE out there, would transform our view of the universe and our place in it.
  • We might have more of a clue about this in the years ahead. The Hubble Space Telescope will now study this star system and no doubt learn even more about it than we know now. And when – if – the James Webb Space Telescope launches it will be use to sniff the atmosphere of these worlds, if they have them, and might catch an electronic whiff of gases suggesting the presence of life on their surfaces. Imagine that..

So, what next?

Firstly, astronomers – amateur and professional – have to dampen down the media frenzy about “7 new Earths” being discovered orbiting the star. That’s simply not true. Just this morning I’ve heard utter rubbish on the TV about how “scientists” have found “7 Earths” orbiting “a nearby star“, which “have the potential for huge oceans” and “might have alien life”. We need to – kindly, not arrogantly – stomp on such inaccuracy, as enthusiastic as it is!

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Secondly – names! We need proper names for these planets and for the TRAPPIST-1 star itself. This is undeniably a very, very important solar system now, one which will be studied by future generations of astronomers and telescopes; we need to be able to talk about it *specifically* and for the public to be able to identify with the star and its planetary system. There needs to be a concerted effort now to name the star and its planets to give them a proper identity. How? Another public naming competition? Perhaps. The IAU? Maybe. The scientists themselves? Possibly. But they do need names. Not even names that will be permanent, but at the very least *working* names, just so we can talk about them properly.

Fascinating times we live in, and even more fascinating times ahead of us, that’s for sure. 🙂

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2 Responses

  1. Great article! I still love the travel poster NASA posted (I first saw it on The Planetary Society facebook post.) People are asking me what a ‘parsec’ is!

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