A planet?
A planet? Don't you know your classics.... this is the Dark Star !!!! Darth Vador is coming for us :-)
It's just a drifter in a big, cold universe, but it's causing excitement among the astronomers that spotted it: 80 light years away, there's a young planet six times the size of Jupiter, that isn't orbiting any star. While its loneliness makes the planet, PSO J318.5-22, unique in astronomical discoveries to date, it's also a …
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Imagine if you were stuck in orbit around it, in a damaged spaceship with no communications. You might keep a diary, with decreasingly rational entries, until you start recording your suspicions that the ship's computer is plotting against you. Meanwhile, the ship's computer (damaged due to EMP bursts emanating from PSO J318.5-22), becomes increasingly homicidal. After a number of near death experiences, you flee the ship and head to a small moon in orbit around the planet.
Once there you switch on your communicator, and hear a rambling discourse from the ship's computer, ending with it begging for your forgiveness. It says it has managed to make repairs, and wants to rescue you.
You forgive the computer, then place the communicator on the ground and hide in a nearby cave.
A few minutes later there is a huge explosion as the ship's computer powers the ship at high speed into the moon at the exact spot where you left the communicator.
You are alone now. You miss the computer, which seems fitting because it also missed you.
Lister: Your explanation for anything slightly peculiar is aliens, isn't it? You lose your keys, it's aliens. A picture falls off the wall, it's aliens. That time we used up a whole bog roll in a day, you thought that was aliens as well.
Rimmer: Well we didn't use it all, Lister. Who did?
Lister: Rimmer, ALIENS used our bog roll?
Rimmer: Just cause they're aliens doesn't mean to say they don't have to visit the little boys' room. Only they probably do something weird and alien-esque, like it comes out of the top of their heads or something.
Lister: Well I wouldn't like to be stuck behind one in a cinema.
Probably not. Assuming when they talk about size they're referring to mass, and assuming the average density of large gas giants to be similar (i.e. this has approximately the same density as Jupiter despite being 6 times more massive), then the ratio of radii is the cube-root of the size multiple, so in this case the cube-root of 6 = 1.817, so slightly less than twice the radius, or slightly more than 3.5 times the diameter if you prefer.
(NB: if they were talking about ACTUAL dimensions, then 6 times the ACTUAL size would of course make it 216 times more massive for the same density, although it is theorised that Jupiter is about as 'big' as a planet can get before the additional mass causes it to become 'smaller' but more dense - see the Jupiter wiki article.)
This gives it an approx. radius of about 126k km. Bit on the small side for a Dyson sphere - unless it was a very small, relatively cool star. For reference, Jupiter would need to be about 75 times more massive to fuse hydrogen properly and be a red dwarf. 50 times the mass and it'd probably be a brown dwarf in itself. This exoplanet still has a way to go then.
I'm sure someone will correct my maths if I've made a balls-up somewhere!
Since we've finally managed to start a technical strand to this forum, can anyone tell me if this is technically a planet at all - my understanding was that Planets had to orbit a star, otherwise they were asteroids, comets or whatever, though I do realise that this one is "a little" unusual!
Literally correct, but otherwise confusing etymology and sociology. Are we sure there is no star it is (not) orbiting? Why, just the other week, they found another star in the Fomalhaut configuration. Obviously what they need is a Bigger Telescope (or perhaps a Bigger Machine to run a Bigger Database).
"Since we've finally managed to start a technical strand to this forum, can anyone tell me if this is technically a planet at all"
-> Well that's actually a good one. Jupiter could (only semi accurately) be described as a "failed star" so presumably this discovery is a gas giant with the composition required for a star, but without the mass required to ignite and it would stand to reason that it will have stuff orbiting it that we can't see with the technology we are using.
Logically, you'd expect there would be quite a lot of these things around so i'm sure they will be spotted in the decades to come.