A Journey in Other Worlds
As they left Pallas between themselves and the sun, it became a crescent and finally
Two days later they sighted another asteroid exactly ahead. They examined it closely, and
concluded it must be Hilda, put down in the astronomies as No. 153, and having almost
the greatest mean distance of any of these small bodies from the sun.
When they were so near that the disk was plainly visible to the unaided eye, Hilda passed
between them and Jupiter, eclipsing it. To their surprise, the light was not instantly shut
off, as when the moon occults a star, but there was evident refraction.
"By George!" said Bearwarden, "here is an asteroid that HAS an atmosphere."
There was no mistaking it. They soon discovered a small ice-cap at one pole, and then
made out oceans and continents, with mountains, forests, rivers, and green fields. The
sight lasted but a few moments before they swept by, but they secured several
photographs, and carried a vivid impression in their minds. Hilda appeared to be about
two hundred miles in diameter.
"How do you account for that living world," Bearwarden asked Cortlandt, "on your
theory of size and longevity?"
"There are two explanations," replied Cortlandt, "if the theory, as I still believe, is
correct. Hilda has either been brought to this system from some other less matured, in the
train of a comet, and been captured by the immense power of "Jupiter, which might
account for the eccentricity of its orbit, or some accident has happened to rejuvenate it
here. A collision with another minor planet moving in an orbit that crossed its own, or
with the head of a large comet, would have reconverted it into a star, perhaps after it had
long been cold. A comet may first have so changed the course of one of two small bodies
as to make them collide. This seems to me the most plausible theory. Over a hundred
years ago the English astronomer, Chambers, wrote of having found traces of atmosphere
in some of these minor planets, but it was generally thought he was mistaken. One reason
we know so little about this great swarm of minor planets is, that till recently none of
them showed a disk to the telescope. Inasmuch as only their light was visible, they were
indistinguishable from stars, except by their slow motion. A hundred years ago only three
hundred and fifty had been discovered; our photographic star-charts have since then
shown the number recorded to exceed one thousand."