Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V15_2/V15NO298.TXT

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Date: Thu,  8 Oct 92 05:04:26
From: Space Digest maintainer <[e-mail]>
Reply-To: [e-mail]
Subject: Space Digest V15 #298
To: Space Digest Readers
Precedence: bulk


Space Digest                Thu,  8 Oct 92       Volume 15 : Issue 298

Today's Topics:
                     Black holes, Sci-Fi Channel
                             Blue Danube
Don't forget  Other Guy(was Re: Von Braun -- Hero, Villain, or Both?)
                          Impact in AD 2000?
     Need info: Fault-Tolerant Spacecraft systems (VLSI-related)
                            SETI positive?
                     UFO EVIDENCE VS. Carl Sagan

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----------------------------------------------------------------------

Date: 8 Oct 92 02:16:18 GMT
From: John Roberts <[e-mail]>
Subject: Black holes, Sci-Fi Channel
Newsgroups: sci.space

-From: [e-mail] (Bill Higgins-- Beam Jockey)
-Subject: Re: BLACK HOLES
-Date: 5 Oct 92 17:05:58 GMT

-In article <[e-mail]>, [e-mail] (Charles Bo Wu) writes:
-> In <[e-mail]> [e-mail] (Sasha Degner) writes:
->>
->>1) What exactly are black holes?
->>2) Is there any truth in the theory that they may be created by alien
->>life forms?
->>3) Is there a black hole close to our galaxy?
->
->     I suggest you to read the book "A Brief History of Time" by
-> Stephen Hawking. An excellent book that tells you just about anything a
-> normal person would want to know about black holes and the Universe.

-I haven't read this book, but I doubt it provides a direct answer to
-question number 2.

By the way, black holes are not universally accepted - they're not nearly
as well-established as neutron stars, for instance. There are some very
good candidates, including some found by HST, for which a black hole is
considered a more likely explanation than any alternates that have been
proposed. It is hoped that WF/PC2 will be able to provide considerable
additional evidence. (I may be overstating the uncertainties a little -
the majority of astrophysists believe they exist, and lack of solid
proof is probably largely because they're hard to observe.)

The literary reference reminds me - the long-awaited Sci-Fi Channel is now
up and running. It's mostly fiction, but it also has some science fact shows,
including "The Science Show" and "Inside Space" - the latter hosted by a
famous science fiction celebrity. Last week's episode included a segment on
virtual reality (with interesting video), and a clip from the *movie*
"A Brief History of Time", which is apparently narrated by the author. (!)

On an amusing note, flipping past the Sci-Fi channel this weekend, I came
across the first images I've ever seen of Brent Spiner without his "Mr. Data"
makeup.

[And they show "Stingray" every weekday morning!]

John Roberts
[e-mail]

------------------------------

Date: Thu, 8 Oct 1992 04:47:44 GMT
From: James Davis Nicoll <[e-mail]>
Subject: Blue Danube
Newsgroups: sci.space

In article <msrMr*[e-mail]> [e-mail] (Jay Denebeim) writes:
>In article <[e-mail]>, Jeff Bytof writes:
>
>> >For some strange reason, I have visions of sleek Pan Am
>> >(RIP) 'liners slowly spinning across a starfield.  Have I gone nuts, or should
>> >I put up my 2001 tape for a while?
>> I'd say for about 100 years.
>
>If its 100 years, its forever.  We'll run out of enough energy to put the
>first SPS up if we don't start much sooner than that.
>

    Nonsense. Fission should be  sufficient. Granted its PR
sucks, but experience shows that people will choose possible
environment problems over probable economic hardship: look
at the history of the laws governing coal use in England in
the last few  centuries.

                        James Nicoll

------------------------------

Date: 8 Oct 92 01:11:39 GMT
From: Steinn Sigurdsson <[e-mail]>
Subject: Don't forget  Other Guy(was Re: Von Braun -- Hero, Villain, or Both?)
Newsgroups: sci.space

In article <[e-mail]> [e-mail] (David Breneman) writes:


   If it hadn't been for inter-department politics in the US government,
   the Soviets would have had the *second* satelite, but the US was (as
   stated policy) in no hurry, and the Soviets wanted to be first at all

Actually I like the rather devious argument I first heard recently
 - probably on the net ;-) - that the US was quite happy to be second
as they wanted the Soviets to establish precedent on limits to
airspace, at the time it was not clear if air space restrictions
extended up to orbit, would have been most inconvenient if pushed by
somebody like the Soviets.

But then again I doubt anyone had much of a coherent policy taking
such factors into account...

|  Steinn Sigurdsson    |I saw two shooting stars last night        |

|  Lick Observatory    |I wished on them but they were only satellites    |
| [e-mail] |Is it wrong to wish on space hardware?        |
| "standard disclaimer"    |I wish, I wish, I wish you'd care - B.B. 1983    |

------------------------------

Date: 8 Oct 92 01:28:42 GMT
From: John Roberts <[e-mail]>
Subject: Impact in AD 2000?
Newsgroups: sci.space

-From: [e-mail] (Nick Szabo)
-Subject: Re: Toutatis impact in 2000 AD? (was Re: Help !)
-Date: 5 Oct 92 06:55:07 GMT

-In article <[e-mail]> [e-mail] (Martin Connors) writes:

->[Earth's diameter is]
->000044 AU so even if Toutatis was coming in randomly within a circle of
->radius 0.011 AU the geometrical chances of impact would be about ten in a
->million. Maybe double that for gravitational focussing.

-This translates to (2e1/1e6)*(5e9) or 10,000 dead people, actuarily
-speaking, or 0.2 per 100,000 population.  The death rate from
-airline crashes is 0.04 per 100,000 people.  Translated into
-more meaningful terms, in the year 2000 each of us has five
-times as much chance of being killed by Toutatis as dying in an
-airline crash.  Presumeabely a more accurate orbit has or soon will
-be predicted, so that we can do a better analysis than
-the quoted, which uses the expected miss distance as the measurement
-error.

I notice you kill just about everybody on the planet, no matter where the
impact. An impact of a two-mile-diameter asteroid would be pretty severe,
but I'm not sure it would be quite *that* bad. Isn't that only about a
tenth of the mass of the alleged "dinosaur killer" asteroid?

The analysis you refer to is apparently just a worst-case scenario - it
wasn't meant to reflect the actual uncertainty in the trajectory. I believe
a later post gives the uncertainty as a fraction of an Earth radius.

John Roberts
[e-mail]

------------------------------

Date: 7 Oct 92 22:02:26 GMT
From: Pascal Gosselin <[e-mail]>
Subject: Need info: Fault-Tolerant Spacecraft systems (VLSI-related)
Newsgroups: sci.space

As a requirement for a VLSI architecture I'm taking this semester, I'd
like to write a paper on the types of fault-tolerant architectures
required on Spacecraft.

I am interested in both the hardware and software aspects of these systems
with emphasis on VLSI's role in all of this (i.e. impact of harsh
environments on system reliability, effects of radiation, etc...).

I have been discouraged somewhat by my teacher, as he thinks most
of the documentation on the subject is probably classified.

Replies by email.

Thanks.

-Pascal
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------------------------------

Date: 8 Oct 92 01:23:49 GMT
From: Paul Colley <ember!pacolley>
Subject: SETI positive?
Newsgroups: sci.space,sci.astro

In article <[e-mail]> [e-mail]
(SCOTT I CHASE) writes:

>                                For example, using this detector at 100 light
                                                                     ^^^
>years from Earth, you could not detect the random TV and radio signals that
                                                   ^^
>we have inadvertantly transmitted out into space.



Oh, drat.  All those fascinating 1890's television shows going unnoticed.
                                 ^^^^

I suppose I'd be more worried if somebody a 100 light-years from
Earth WAS currently watching our TV broadcasts!

-----

I know, I know, Scott meant "100 years from now.... this equipment
wouldn't detect our current radio and TV broadcasts at a 100
light-year distance".

- Paul Colley
University:  [e-mail]
Home:        [e-mail]   watmath!ember!pacolley  [phone]
<Ring> [...] "Sorry, I'm all booked up." "Who was that?" "The library." - B.C.

------------------------------

Date: 7 Oct 92 12:48:11 GMT
From: [e-mail]
Subject: UFO EVIDENCE VS. Carl Sagan
Newsgroups: sci.space

In <[e-mail]> Jeff Bytof writes:
>(I am of course referring to Dr. Sagan's hobby interests - "ethical
                              ============
  Has Carl Sagan actually got a doctorate in anything ???  Last I heard
(long time ago , true) he was just plain ol' C. Sagan
 -----------------------------------------------------------------
               ** Of course I don't speak for IBM **
Greg Nicholls ... [e-mail] or [e-mail]
                  voice/fax: [phone]

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End of Space Digest Volume 15 : Issue 298
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