# How Big the fountain

*The Urth list — 2 messages, 2 voices, 05 Apr 1999*

<https://urth.darkrealm.vip/thread/urth/1483>

> Exported from an unofficial mirror of a public mailing list. Copyright
> in each message remains with the person who wrote it.
> Email addresses are obscured as `user at host`, the form the original
> archive published. This file was rebuilt from parsed fields rather than
> retained headers, so it is faithful in content but not byte-exact.

---

### m.driussi
*05 Apr 1999, 17:11*

In my reading, the possible paradox would be whether or not the white
fountain exists, not "if it exists then why can't it be seen from
Urth."

Because it can be seen from Urth.  It just isn't as impressive as a
full moon or a hot air balloon.

IF the white fountain is a "white hole" that is roughly equal in mass
to the black hole eating at the heart of the old Sun, AND IF the
black hole is a mini-black hole as would fit the description of
effects in the text, THEN the white hole would have a small diameter.

"How far can you see the light from a motorcycle's headlight?"

A black hole with the mass of Jupiter would have a diameter of 560
centimeters; one with the mass of Earth would have a diameter of 1.6
centimeters.

"It depends on how far away the motorcycle is, and if it is moving
then it will become more visible as it gets closer."

Severian is gone from Urth for 40 years.  If the fountain is
traveling at .5 c for 40 years (ignoring deceleration times) then it
has crossed 20 light years; it was 20 light years away when he left.
If it is traveling faster, it has covered a greater distance (up to
around 40 light years); if it is traveling slower, it has covered a
shorter distance.  In any event: it is within 40 light years of Urth.

"There are literally thousands of stars within the Local Bubble alone
that outshine our star.  To illustrate the point, we have marked on
Map C an obscure star in Puppis called HD 44594, which is just too
faint to be seen by the naked eye.  HD 44594 is in fact the twin of
the Sun--the nearest match to our star that astronomers have been
able to pin down.  Just as we do not rate HD 44594 highly, someone in
this star's planetary system--if it has one--would regard our Sun as
a totally insignificant star, invisible without a telescope, even
though it lies only 80 light years away" (Henbest & Couper, THE GUIDE
TO THE GALAXY, p. 185).

The "solar twin" (with a diameter like that of the Sun) cannot be
seen without a telescope, yet it is only 80 light years away.

"The German astronomer Wilhelm Gliese has made a detailed study of
the nearest stars to the Sun.  Within 16 light years of the Sun--the
region where we =probably= have a complete inventory, even of the
faintest stars . . . " [emphasis mine] (ibid.).

Even in the 20th century, with advanced optical telescopes and radio
telescopes, etc.,  our knowledge of our stellar neighborhood is
limited to 16 or 20 light years.  Beyond 20 light years things get
progressively more fuzzy, spotty.  It is much easier to see the big
stars--our nearest solar twin is out there, lost to naked eye at 80
light years.

=mantis=

---

### Roy C. Lackey
*06 Apr 1999, 02:09 · follows m.driussi*

>> On Mon,  5 Apr 99 17:11:00 GMT mantis wrote:
>> In my reading, the possible paradox would be whether or not the white
>> fountain exists, not "if it exists then why can't it be seen from
>> Urth."

Because it can be seen from Urth.  It just isn't as impressive as a
full moon or a hot air balloon.<<

<snip> and:

>> The "solar twin" (with a diameter like that of the Sun) cannot be
>> seen without a telescope, yet it is only 80 light years away.<<

<snip> and:

>> Even in the 20th century, with advanced optical telescopes and radio
>> telescopes, etc.,  our knowledge of our stellar neighborhood is
>> limited to 16 or 20 light years.  Beyond 20 light years things get
>> progressively more fuzzy, spotty.  It is much easier to see the big
>> stars--our nearest solar twin is out there, lost to naked eye at 80
>> light years.<<

    All true. But Sev, at least, can see his "star", his "white fountain" as
far back in time as when Typhon and Ymar were alive. See the last line of
chapter  XXXV, _Urth_:

"Before we walked into the darkness beneath the trees, I looked up and
beheld myself through their frost-blighted leaves."

    This implies that Sev's "star" should have been visible to the naked eye
for however many millennia had passed between Typhon's reign and Sev's,
presumably getting brighter, to some degree, all the while. That's why I
said what I did about time-travel paradoxes; they're unavoidable. Not to
mention why the "fountain" should have been one of the three emblems on
Sev's mausoleum, ancient when Sev was just a boy.

    This only serves to show that the Physics can not be reconciled with the
Fiction. For time-travel stories it just comes with the territory. In a
similar vein, someone(s) tried to deduce the dimensions of the Whorl from
distances given in the text and the laws of physics as applied to the
motions of "floaters" and such. IIRC, they couldn't be reconciled either.
Nor, IMO, should Wolfe be criticized for it; he made the Whorl exactly as
large as it needed to be to hold his story, and no smaller.

Roy

---