1. Forum
  2. Fidonet
  3. REC.ARTS.SF.WRITTEN

  • Re: Review: Halcyon Years, Alastain Reynolds

    From Default User@3:633/10 to All on Thu Jul 9 22:30:29 2026
    Titus G wrote:

    I can't get my head round huge numbers such as 2,200 years travelling
    at 99% of the speed of light being equivalent to more than 15,000
    years in the rest of the universe.

    Reynolds is an astrophysist, so I'd hope he'd get that sort of thing
    right.


    Brian

    --- PyGate Linux v1.5.18
    * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)
  • From Christian Weisgerber@3:633/10 to All on Fri Jul 10 17:36:36 2026
    On 2026-07-09, Default User <defaultuserbr@yahoo.com> wrote:

    I can't get my head round huge numbers such as 2,200 years travelling
    at 99% of the speed of light being equivalent to more than 15,000
    years in the rest of the universe.

    Reynolds is an astrophysist, so I'd hope he'd get that sort of thing
    right.

    Plugging the numbers into the time dilation equation isn't exactly
    rocket science.
    https://en.wikipedia.org/wiki/Time_dilation

    99% c gives a Lorentz factor of ... *types on HP-11C* ... 7.09.
    Which would agree with the approximate figures above.

    --
    Christian "naddy" Weisgerber naddy@mips.inka.de

    --- PyGate Linux v1.5.18
    * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)
  • From Lawrence D?Oliveiro@3:633/10 to All on Sun Jul 12 06:48:05 2026
    On Wed, 24 Jun 2026 17:39:53 +1200, Titus G wrote:

    15,000 years ... are they headed for the centre of the galaxy?

    No. Away from the centre, far away.

    What is there in that direction? One of the Magellanic Clouds,
    perhaps?

    --- PyGate Linux v1.5.18
    * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)
  • From Cryptoengineer@3:633/10 to All on Sun Jul 12 16:16:44 2026
    On 6/24/2026 1:39 AM, Titus G wrote:
    On 24/06/2026 14:17, Lawrence D?Oliveiro wrote:
    On Thu, 11 Jun 2026 16:20:47 +1200, Titus G wrote:

    I can't get my head round huge numbers such as 2,200 years
    travelling at 99% of the speed of light being equivalent to more
    than 15,000 years in the rest of the universe.

    The Lorentz factor sounds about right
    <https://en.wikipedia.org/wiki/Length_contraction>:

    import math

    ? = lambda v : 1 / math.sqrt(1 - v * v)
    # Lorentz factor, v being speed as a fraction of c

    ?(.99)
    ? 7.088812050083354

    15,000 years ... are they headed for the centre of the galaxy?

    No. Away from the centre, far away.

    Going 15 kly further out puts you pretty near the outer edge of
    our galaxy.

    pt

    --- PyGate Linux v1.5.18
    * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)
  • From Titus G@3:633/10 to All on Mon Jul 13 18:19:44 2026
    On 12/07/2026 18:48, Lawrence D?Oliveiro wrote:
    On Wed, 24 Jun 2026 17:39:53 +1200, Titus G wrote:

    15,000 years ... are they headed for the centre of the galaxy?

    No. Away from the centre, far away.

    What is there in that direction? One of the Magellanic Clouds,
    perhaps?

    In the novel, the ship has a clearly defined destination; see my reply
    to pt.

    --- PyGate Linux v1.5.18
    * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)
  • From Titus G@3:633/10 to All on Mon Jul 13 18:20:01 2026
    On 13/07/2026 08:16, Cryptoengineer wrote:
    On 6/24/2026 1:39 AM, Titus G wrote:
    On 24/06/2026 14:17, Lawrence D?Oliveiro wrote:
    On Thu, 11 Jun 2026 16:20:47 +1200, Titus G wrote:

    I can't get my head round huge numbers such as 2,200 years
    travelling at 99% of the speed of light being equivalent to more
    than 15,000 years in the rest of the universe.

    The Lorentz factor sounds about right
    <https://en.wikipedia.org/wiki/Length_contraction>:

    ÿÿÿÿ import math

    ÿÿÿÿ ? = lambda v : 1 / math.sqrt(1 - v * v)
    ÿÿÿÿÿÿ # Lorentz factor, v being speed as a fraction of c

    ÿÿÿÿ ?(.99)
    ÿÿÿÿ ? 7.088812050083354

    15,000 years ... are they headed for the centre of the galaxy?

    No. Away from the centre, far away.

    Going 15 kly further out puts you pretty near the outer edge of
    our galaxy.

    pt

    The ship movement, including destination, is plot related so to avoid
    spoilers, I can say no more.

    --- PyGate Linux v1.5.18
    * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)
  • From Tony Nance@3:633/10 to All on Mon Jul 20 11:15:55 2026
    On 7/10/26 1:36 PM, Christian Weisgerber wrote:
    On 2026-07-09, Default User <defaultuserbr@yahoo.com> wrote:

    I can't get my head round huge numbers such as 2,200 years travelling
    at 99% of the speed of light being equivalent to more than 15,000
    years in the rest of the universe.

    Reynolds is an astrophysist, so I'd hope he'd get that sort of thing
    right.

    Plugging the numbers into the time dilation equation isn't exactly
    rocket science.
    https://en.wikipedia.org/wiki/Time_dilation

    99% c gives a Lorentz factor of ... *types on HP-11C* ... 7.09.
    Which would agree with the approximate figures above.


    Hp-11C...Hp-11C... That was one of the HPs that used "reverse polish notation", right? I remember that being confusing and delightful, all at
    the same time.

    Tony

    --- PyGate Linux v1.5.18
    * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)