On An Asteroid II

Sunday through Wednesday, Sheila and I in the Republic of Ireland without the laptop. It will be an absolute desert, like totally, for new blog posts. Meanwhile, regular commentators (you know who you are) and any new commentators, please send new comments that will be read with interest on our return.

Poul Anderson, The Stars Are Also Fire, 20.

Edmond Beynac postulates an ancient lost body, I do not know on what grounds. It is something to do with the distribution of the asteroids in the Belt.

The small remote asteroid that he and others explore is principally metals including iron and nickel which were once fused which means that this body is a piece from the core of another body which had been large enough to melt and form a core. This small asteroid has a flat section which is a fracture where the larger body broke in a collision. However, the type of traces on this asteroid indicate that the larger body was not entirely shattered. The collision probably pushed the main body and its fragments into an eccentric orbit. Jovian gravity flung them outward so that they either escaped the Solar System or entered an enormous orbit which, over billions of years, would have been extended further by the gravity of passing stars. (Beynac says that passing stars would "'...raise its perihelion...'" (p. 267) but should he have said "aphelion"?) A comet in the Oort Cloud changed the orbit of this small asteroid so that it has returned to nearer the sun but its orbit remains unstable so it must have returned in the last few million years. This suggests that the larger body is not currently at the farthest point of is orbit and it might be possible to compute where to search for it.

The asteroid is a rough cylindroid. Near its middle is the fracture plane, ten kilometers by twenty, surrounded by rock that either remained stuck to the core during the collision or fell back onto it, half-molten. Meteor strikes were rare in the Oort Cloud so there are few craters. To one side of the fracture scar is a peak visible from space, possibly formed by a shock wave hurling immediately congealing liquefied metal upward. There is more, which might be the basis of another post.

When discussing Satan And Mirkheim (see also The Surface Of Mirkheim), we sometimes found that natural processes can be as dramatic as historical events.