"It will be some time."
Again that unwillingness to discuss the future. Guy thought it over and
decided that this was something beyond him. He, too, let the matter
drop for the present and took a new subject.
"Charalas, this sun of yours. It is not a true sun."
"No," laughed Charalas. "It is not."
"Nor is it anything like a true sun. Matter is stable stuff only
under certain limits. If that size were truly solar matter, it would
necessarily be so dense that space would be warped in around it so
tight that nothing could emerge--radiation, I mean. To the observer, it
would not exist. That is axiomatic. If a bit of solar matter of that
size were isolated, it would merely expand and cool in a matter of
hours--if it were solar-core matter it would probably be curtains for
anything that tried to live in the neighborhood. Matter of that size is
stable only at reasonable temperatures. I don't know the limits, but
I'd guess that three or four thousand degrees kelvin would be tops. Oh,
I forgot the opposite end; the very high temperature white dwarf might
be that size--but it would warp space as I said before and thus do no
good. Therefore a true sun of that size and mass is impossible.
"Another thing, Charalas. We are close to Sol. A light-week or
less. That would have been seen ... should have been seen by our
observatories. Why haven't they seen it?"
* * * * *
"Our shield," explained Charalas, "explains both. You see, Guy, in
order that a planet may wander space, some means of solar effect must
be maintained. As you say, nothing practical can be found in nature.
Our planet drive is poorly controlled. We can not maneuver Ertene
as you would a spaceship. It requires great power to even shift the
course of Ertene by so much as a few degrees. We've taken luck as a
course through the galaxy and have visited only those stars that have
lain along our course. Trying to swing anything of solar mass would be
impossible. Ertene would merely leave the sun; the sun would not answer
Ertene's gravitational pull.
"But this is trivial. Obviously we have no real sun. But we needed
one." Charalas smiled shyly. "At this point I must sound braggart," he
said, "but it was an ancestor of mine--Timalas--who brought Ertene her
sun."
"Great sounding guy," commented the Terran.
"He was. Ertene left the parent sun with only the light-shield. The
light-shield, Guy, is a screen of energy that permits radiation to pass
inwardly but not outwardly. Thus we collect the radiation of all the
stars and lose but a minute quantity of the input from losses. That
kept Ertene warm during those first years of our wandering.
"It also presented Ertene with a serious problem. The entire sky was
faintly luminous. It was neither night nor day at any place on Ertene,
but a half-light all the time. Disconcerting and entirely alien to the
human animal. Evolutionary strains might have appeared to accept this
strange condition, but Timalas decided that Intis, the lesser moon,
would serve as a sun. He converted the screen slightly, distorting
it so that the focal point for incoming radiation was at Intis. The
lesser moon became incandescent, eventually, and serves as Ertene's
sun. It is synthetic. The other radiations that prove useful to growing
things and to man but which are not visible are emitted right from
the inner surface of the light-shield itself. Intis serves as the
source of light and most of the heat. It is a natural effect, giving
us beautiful sunrises and peaceful sunsets. The radiation that causes
growth and healthful effects is ever-present, because of the screen.
Some heat, too, for that is included in the beneficial radiation. But
the visible spectrum is directed at Intis along with a great quantity
of the heat rays. Intis is small, Guy, and it is also beneficial that
the re-radiation from Intis that misses Ertene and falls on the screen
is converted also. Much of Ertene's power is derived from the screen
itself--a back-energy collected from the screen generator."
"So the effective sun is the result of an energy shield? And this same
shield prevents any radiation from leaving this region. I can see why
we haven't seen Ertene. You can't see something that doesn't radiate.
But what about occultation?"
"Quite possible. But the size of the screen is such that it is of
stellar size as seen from stellar distances. It is but a true point in
space." Charalas smiled. "I was about to say a point-source of light
similar to a star but the shield is a point-source of no-light, really.
Occultation is possible but the probabilities are remote, plus the
probability of a repeat, so that the observer would consider the brief
occultation of the star anything but an accident to his photographic
plate."
"Don't get you on that."
"It's easy, Guy. Take a star-photograph and lay a thin line across it
and see how many stars are really covered by this line--which is of
the thickness of the stars themselves. Too few for a non-suspecting
observer to tie together into a theory. No, we are safe from detection."
"Detection?"
"Yes. Call it that. Suppose we were to pass through a malignant
culture. We did, three generations ago and it was only our shield that
saved us from being absorbed into that system. We would have been
slaves to that civilization."
"I see."
"Do you?"
"Certainly," said Guy. "You intend to have me present the Solar
Government to your leaders. Upon my tale will rest your decision. You
will decide whether to join us--or to pass undetected."
"I believe you understand," said Charalas. "So study well and be
prepared to draw the most discerning comparisons, for the Council will
ask the most delicate questions and you should be able to discuss any
phase of Ertene's social system and the corresponding Terran system."
Mentally, Guy bade good-by to Sol. He applied himself to his Ertinian
lessons because he felt that if Sol were lost to him--as it might
be--he could at least enter the Ertinian life as an Ertinian.