[time-nuts] Time of death-Again

Jim Palfreyman jim77742 at gmail.com
Thu Oct 28 21:05:24 EDT 2010


Neville,

The Time of Arrival error for the millisecond pulsar J0437-4715 is about 11
nsec. This takes into account the location of the pulsar, the solar system's
barycentre, the earth's (perturbed) orbit around that barycentre and not to
mention the interstellar medium that the pulse has to travel through and be
dispersed by - all to an accuracy of about 3m.

Not bad and certainly not rubbery!

Regards,

Jim


On 29 October 2010 10:46, Neville Michie <namichie at gmail.com> wrote:

> Surely astronomical events are rather rubbery.
> The distance between the celestial bodies is measured in Light Years,
> this must give uncertainties as the exact distances are varying all the
> time
> and the solution of the many bodied problem is probably chaotic, meaning
> that it
> may not be possible to deduce exactly where anything was at some point in
> the past.
> The rate at which time happens depends on the local gravity and that varies
> as
> everything moves around.
> What we need here is a Grand Unified Time to keep cell phones working
> through the universe. How would you administer that to a nanosecond?
> I am sure Douglas Adams would have had some humorous situations with
> excellent moral messages for us if he were still here.
> cheers, Neville Michie
>
>
>
> On 29/10/2010, at 5:18 AM, Marshall Eubanks wrote:
>
>
>> On Oct 28, 2010, at 2:05 PM, Max Robinson wrote:
>>
>>  How about the crab supernova.
>>>
>>>
>> Msec pulsars are much more stable - see http://arxiv.org/pdf/0911.5534for some comparisons.
>>
>> Regards
>> Marshall
>>
>>  Regards.
>>>
>>> Max.  K 4 O D S.
>>>
>>> Email: max at maxsmusicplace.com
>>>
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>>> ----- Original Message ----- From: "jimlux" <jimlux at earthlink.net>
>>> To: "Discussion of precise time and frequency measurement" <
>>> time-nuts at febo.com>
>>> Sent: Thursday, October 28, 2010 8:30 AM
>>> Subject: Re: [time-nuts] Time of death-Again
>>>
>>>
>>>  Steve Rooke wrote:
>>>>
>>>>> One thing we should bear in mind that our tombstone timestamp should
>>>>> have things like the timezone, and calendar in use, references, such
>>>>> that future people can determine the exact point in time of our death.
>>>>> In fact, basing the timestamp on some true reference point would
>>>>> better than about 2000 years after some event happened on earth as
>>>>> archaeologists from other words coming to the Earth in the future
>>>>> would be left to figure out this arbitrary time event. I would propose
>>>>> that we relate the year portion (which is the LSB and most important)
>>>>> to some celestial event thereby making it possible to document this
>>>>> easily for future life-forms to determine. The whole year/date thing
>>>>> really should be made secular as there is no place for religion in the
>>>>> governance of society.
>>>>>
>>>>> Steve
>>>>>
>>>>
>>>>
>>>> Is this not the same problem we all face when specifying an absolute
>>>> time? Is it TAI? GPS? UTC? etc.
>>>>
>>>> And, then, if you are moving, the local time offsettime  relative to
>>>> some reference might be different at different times.
>>>>
>>>> I think this is a sort of relativity question, isn't it?  That is, you
>>>> just have to pick some place/time, and reference everything else to that. So
>>>> which astronomical event do you want use as your reference (e.g. a T=0
>>>> epoch)and is it sufficiently well determined that you can figure it out
>>>> later?  It's all well and good, for instance, to use noon on January 1st,
>>>> 1900 or something as your time zero, but that's hardly a universally
>>>> available reference point.
>>>>
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>>>
>>>
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