[meteorite-list] Extra solar impactors and comets

[Kevin Forbes]

Greetings all,

a thought to pervade your mind and something else to contemplate apart from 
your navel.

The oort cloud, the very outer extremeties of our solar system, millions of 
bodies, probably mainly ices mixed with silicates. Cometary bodies and 
planetary orbs lost to the depths of space. But, they are there. Other star 
systems probably have a similar 'oort' thing around them, slowy following 
the gravitational attraction of the central star in that system as it drifts 
through the galaxy. Over time, a passing of stars occurs, not an entirely 
close call, but one that would allow material and bodies of one system to 
migrate or be stolen by the other system. A dramatic change in course for 
the migrating body, some may just change from their origanl formation parent 
to their new foster star and stay in the darkness, some may have a different 
set of motions inflicted upon them, sending them on a course that sweeps 
through the inner system of rocky planets. Look out.

How many orphans are there in space, not gravitationally attached to any 
star, having either been ejected through orbital conflicts in a system with 
a larger more massive body, or formed ( I shall call this, 'A Dark System' ) 
a dark system, a coagulation of material from a cloud of dust and icy 
particles  that certainly forms lumps, but comes nowhere near that of 
forming a solar system. How many 'Dark Systems' are there, and how often do 
they collide with star systems and loose material or meld with.

And now, I must make a comment regards a statement by a scientist that made, 
in my opinion, an awakening utterance. At first I thought, 'outrageous', 
'how silly'. Silicate dusts were found in cometary debris, he therefore 
postulated that comets must have formed near the sun. ????????????

In my mind, I see bodies of the inner solar system being the source of the 
silicate dusts, their constant impacts creating a constant supply of fine 
dusts that would be blown by solar wind to the extremeties of the outer 
solar system, where they would fall upon any icy cometary bodies that they 
happened to chance upon. It must be obvious to that icy bodies such as 
comets would NOT form near the sun, due to the temperature being high. Any 
comets hanging around near the inner solar system, Jupiter and inwards would 
quickly evaporate. Comets must be born in the cold outer reaches of our or 
other systems. Some comets in our system at this moment may have been stolen 
from passing systems as the two interacted for a period during their passing 
of each other. The fact that there are silicate dusts mixed up in the ices, 
would suggest that they have been collecting 'fairy dust' for a period of 
time. What could have happened??? Perhaps before the sun burst into life, in 
the pre-solar nebula, the bulk of the comets did in fact reside in the inner 
solar system. When the larger bodies began to accumulate they were ejected 
en-masse to the outer reaches where they are now existing as a record of 
what happened, waiting for us to go there, and study. Can isotopic ratios 
give us a clue as to there original place of formation in the solar nebula?

Is our understanding of such things as isotopic data and distribution 
satisfactory to enable this?

I have been absent from the list for a while, I may have missed something 
that I should not have.

If you are thinking that I need a thick ear, then please, bash away.

Yours faithfully, Kevin Forbes, VK3UKF.