Discussion
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.
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.
Pesty said:
Some stupid questions
Is the surface dusty
With low gravity why don't the small stones float away.
Every time it goes near the sun it vents gas. Is it getting smaller
They are very good questions - Is the surface dusty
With low gravity why don't the small stones float away.
Every time it goes near the sun it vents gas. Is it getting smaller
The surface seems to be LESS dusty than expected. However, they were surprised by the number of rocks and boulders.
An object resting on the surface will stay there unless a force is applied to the object (Newtons 1st law of gravity - an object either remains at rest or continues to move at a constant velocity, unless acted upon by an external force). So it won't float off unless a force is applied to it. The venting of gas and other material from beneath the surface could, of course, blast rocks and dust out into space - never to come back.
Any comet that gets close to the sun will lose mass - so yes, it is getting smaller. Eventually, the comet will disintegrate - but it might take a couple of million years.
Air is not the only agent of erosion.
All the mountains of the moon are rounded off despite the fact that there is no air. They have been eroded by 4 billion years of micrometeorite impact.
On a comet there will be quite dramatic temperature shifts - especially during its passage close to the sun, which will cause fractures, melting, outgassing and even explosions - so plenty of scope there for rocks and ice to be broken up and flung about.
All the mountains of the moon are rounded off despite the fact that there is no air. They have been eroded by 4 billion years of micrometeorite impact.
On a comet there will be quite dramatic temperature shifts - especially during its passage close to the sun, which will cause fractures, melting, outgassing and even explosions - so plenty of scope there for rocks and ice to be broken up and flung about.
NASA is a pretty unique governmental organisation. It was set up by Eisenhower SPECIFICALLY to do things very different to the way governments and the military normally conduct themselves.
NASA was intended to be a showcase for the open, frank and honest way the US wanted to conduct itself in space research and as a complete contrast to the secretive and hidden way the Soviets were seen to be conducting their space efforts.
It is in their DNA to be open and very public orientated. ESA is not quite the same, being more typical of state funded bodies.
NASA was intended to be a showcase for the open, frank and honest way the US wanted to conduct itself in space research and as a complete contrast to the secretive and hidden way the Soviets were seen to be conducting their space efforts.
It is in their DNA to be open and very public orientated. ESA is not quite the same, being more typical of state funded bodies.
XM5ER said:
Eric Mc said:
Why would you want that particular theory to be scotched? It's still a valid one - and might very well remain valid as examining one comet out of millions is not going to answer all the questions we have about comets.
Mainly because every time a comfortable consensus is blown out of the water lots and lots of exciting new science happens. Secondly, I prefer the idea that life arose on earth without any help from the sky. I saw a great interview with Neil deGrasse Tyson where he pulls apart the "we're special" argument really well, pointing out that carbon and hydrogen (the basis of life on earth) are so abundant in the universe that the life is not so much unusual as inevitable.So, I would say that there can be no other way for the materials that form life to arrive on a planet - because that is how planets form in the first place.
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