Discussion
ash73 said:
Strange that in the programme the guy with the tats said they hope to stay in orbit for "the next couple of months" when 67P perihelion is Aug 2015...?
As it gets closer to the sun it will start to gas out. Sure there is a correct term for it. Depends how well it can maintain orbit.Mr Gear said:
So on a serious note, there will still be plenty of good stuff coming back from Rosetta in the future?
I gather there's an ambitious plan to actually land Rosetta on the comet at the end of its planned programme. No reason not to try I suppose, and give us some decent photos from the surface. 
ash73 said:
Strange that in the programme the guy with the tats said they hope to stay in orbit for "the next couple of months" when 67P perihelion is Aug 2015...?
I think he was referring to what they planned for "the next couple of months" rather than the mission as a whole. (He had a splendidly inappropriate shirt for TV too, Kudos!)
I suspect that ESA are conscious of the fact that Rosetta is orbiting in the firing line of unknown amounts of "off gassing" the comet might just gentle spew a few misty particles as it passes the sun of it might erupt like a geyser, no one knows. If it starts firing out big pieces Rosetta might not last long at its current range- lets hope 67P puts on a grand show however long we get to watch.
I too recall some debate about parking Rosetta on the comet at the end but not sure if that preceded Philea joining the mission design, either way it would be a grand send off to the mission.
jammy_basturd said:
How do we know another collision hasn't changed it's original trajectory?
Whilst extreme, my point is that we've been observing this comet for what, a few decades? We have no idea of its history beyond that?
True, but we've been observing comets in general for a lot longer and have a decent idea of their origins and behaviour. Ditto the Moon and other planets. A recent collision big enough to leave a 6km chunk in orbit would have created an awful lot of other debris, not to mention what it would have done to the body it hit. Something on that scale would have been noticed - look at the Schoemaker-Levy 9 impact with Jupiter. Seriously suggesting it's a fragment of a recent collision with the Moon is up there with suggesting it's actually an alien probe in terms of the ridicule it's likely to attract.Whilst extreme, my point is that we've been observing this comet for what, a few decades? We have no idea of its history beyond that?
There is no evidence whatsoever to link it in any way with our moon - and no sensible planetary scientist would make such a link. For a start, it's a comet - which are made from quite different materials to our moon - and they have trajectories which indicate that they come in from the distant Oort cloud - not from a game of planetary billiards within the inner solar system.
Shades of Velikovsky at work here.
Shades of Velikovsky at work here.
MartG said:
thatdude said:
That Matt dude, his t-shirt is awesome and it's terrible people made him feel so bad for wearing it.
Surprised the whiners didn't have a go about his tats too
king feminist dheads. The achievement of his life, and his first act was to break down in tears because of some stupid slight that fking rug-munchers feel victimised over, rather than punch the air and shout about how it's 10 years of waiting, not to mention however many years of work prior to launch. I'd have just said it's a tribute to Barbarella, and get f
ked if it causes offence. But no. Stupid f
king femenists want equality, but only if it's in their favour. Poor guy. I hope his next T-shirt is a photo of a pair of tits and a middle finger.
hornet said:
jammy_basturd said:
How do we know another collision hasn't changed it's original trajectory?
Whilst extreme, my point is that we've been observing this comet for what, a few decades? We have no idea of its history beyond that?
True, but we've been observing comets in general for a lot longer and have a decent idea of their origins and behaviour. Ditto the Moon and other planets. A recent collision big enough to leave a 6km chunk in orbit would have created an awful lot of other debris, not to mention what it would have done to the body it hit. Something on that scale would have been noticed - look at the Schoemaker-Levy 9 impact with Jupiter. Seriously suggesting it's a fragment of a recent collision with the Moon is up there with suggesting it's actually an alien probe in terms of the ridicule it's likely to attract.Whilst extreme, my point is that we've been observing this comet for what, a few decades? We have no idea of its history beyond that?
What we cannot take into account however is any changes to an objects trajectory/orbit due to objects or forces we're yet to observe, if that change occurred before we started observing said object.
Therefore we cannot make any assumptions about the origins of this comet. Surely.
That is a shame, looks like one of the legs may have dug in deeper than the others and caused an off set bounce to the cliffy bit.
It was a decent straight line 'til then
Oh well, who knows? It might have bounced off a smooth bit back into space, at least it is still there ready to recharge one day.
All in all, a tremendous thing to have done
Well done ESA and humanity
and "rude words" to the -ists that had to carp about a bloody shirt, I despair sometimes
It was a decent straight line 'til then
Oh well, who knows? It might have bounced off a smooth bit back into space, at least it is still there ready to recharge one day.
All in all, a tremendous thing to have done
Well done ESA and humanity
and "rude words" to the -ists that had to carp about a bloody shirt, I despair sometimes
Edited by perdu on Monday 17th November 19:39
jammy_basturd said:
My point is, I know we can work out the orbit and trajectories of every observable object and using some clever and powerful computer systems, we can work out where orbits have changed due to influence/collision with other bodies.
What we cannot take into account however is any changes to an objects trajectory/orbit due to objects or forces we're yet to observe, if that change occurred before we started observing said object.
Therefore we cannot make any assumptions about the origins of this comet. Surely.
We can, of course, because comets do seem to be sourced from a spot WAY beyond the furthest planets a LONG way from the sun. And it's because they live out there that they last so long and contain primordial material from the beginning of the Solar System. What we cannot take into account however is any changes to an objects trajectory/orbit due to objects or forces we're yet to observe, if that change occurred before we started observing said object.
Therefore we cannot make any assumptions about the origins of this comet. Surely.
They are fragile objects - mostly frozen gases with some rock. If they start coming in to orbit the sun more closely i.e. looping inside the orbit of (say) Jupiter (like this one), then they are essentially doomed. They cannot survive close encounters with the sun as they gradually lose their mass over time and eventually disintegrate.
So, a comet can live 4.5 billion years out in the Oort Cloud - but once it falls in towards the sun, its remaining life may be less than a million years - probably a lot less.
jammy_basturd said:
My point is, I know we can work out the orbit and trajectories of every observable object and using some clever and powerful computer systems, we can work out where orbits have changed due to influence/collision with other bodies.
What we cannot take into account however is any changes to an objects trajectory/orbit due to objects or forces we're yet to observe, if that change occurred before we started observing said object.
Therefore we cannot make any assumptions about the origins of this comet. Surely.
http://en.wikipedia.org/wiki/67P/Churyumov–Gerasimenko#Orbital_historyWhat we cannot take into account however is any changes to an objects trajectory/orbit due to objects or forces we're yet to observe, if that change occurred before we started observing said object.
Therefore we cannot make any assumptions about the origins of this comet. Surely.
Changes to the comet's orbit have already been inferred. Despite only being discovered in 1969, it had had an encounter with Jupiter in 1959, which presumably was discovered by running orbital models back in time.
The further back you go obviously the less certain you can be.
MartG said:
Rosetta's OSIRIS camera images of Philae during its bounces - looks like they were really unlucky to end up in a shaded location
AMAZING, we scored a 4billion mile spin bowled wicket! Surprised at the direction it went, how does that relate to the comets spin I wonder? It does seem to have been scooped up by a big cliff, alittle bigger bounce and it might have got into the next "valley"At least we know where it is now...
QuantumTokoloshi said:
Does the comet not rotate or tumble at all?
Yes, of course.QuantumTokoloshi said:
If it does, then it should expose the lander to some sunlight during the day.
It's at the bottom of a cliff, it gets about 1.5 hours per 'day' of light - not enough to even warm the batteries up to charge. As the comet comes sunward this may change.Einion Yrth said:
QuantumTokoloshi said:
Does the comet not rotate or tumble at all?
Yes, of course.QuantumTokoloshi said:
If it does, then it should expose the lander to some sunlight during the day.
It's at the bottom of a cliff, it gets about 1.5 hours per 'day' of light - not enough to even warm the batteries up to charge. As the comet comes sunward this may change.Gassing Station | Science! | Top of Page | What's New | My Stuff