Pat:
You seem to be throwing zeroes around with abandon.
The current estimate for the age of the Universe is about 13.5 billion
years. That's 13 500 000 000, which is less than one thousandth of the
15 000 000 000 000 (15 trillion) you cite (a figure with which only
Scientologists are likely to agree). Also, it's not expanding at the
speed of light (an impossibility, according to Einstein).
However, rather than my looking up the rate of expansion (which is, in
any case, an estimate that has changed over the years -- just ask your
friendly neighborhood astrophysicist), I suggest you do that yourself
and redo your calculation. I think you'll come up with something
considerably smaller than 285 Ym.
I think yottameters may be useful for speculation about how big the
Universe might be when it approaches its ultimate cold and lifeless
state. (Oh, entropy, where is thy sting?) That time is a yotta—oops,
lotta—seconds away.
Best regards,
Bill
------------------------------------------------------------------------
Bill Potts
WFP Consulting <http://wfpconsulting.com/>
Roseville, CA
http://metric1.org <http://metric1.org/> [SI Navigator]
Dear Bill,
Thanks for your thoughts. Perhaps it will help if I place it into
context for you. Let's say that I want to write these paragraphs:
The 'Big bang' theory of the Universe is based on the observation that
all the stars and galaxies in the Universe seem to be moving away from
each other. If you calculate their speeds of separation, you can
calculate that the Universe might have begun with a 'Big Bang'
15 000 000 000 000 years ago. As we observe the speeds using light, it
follows that the diameter of the Universe is twice the distance that
light can travel in 15 000 000 000 years or the diameter requires
30 000 000 000 years. As light travels nearly 9 500 000 000 000
kilometres in a year, this means that the Universe is approximately:
30 000 000 000 years multiplied by 9 500 000 000 000 kilometres per year
which equals 285 000 000 000 000 000 000 000 kilometres
This is a very large number and before the metric system was developed
people, even scientists and mathematicians, had difficulty saying or
writing such big numbers. These days we simply say that the diameter of
the Universe is about 285 yottametres. The metric system has given us
simple methods to handle very large numbers, very small numbers, and all
of the numbers in between.
------------------------------------------------------------------------
*From:* [email protected] [mailto:[email protected]]
*On Behalf Of *Pat Naughtin
*Sent:* Tuesday, March 24, 2009 02:01
*To:* U.S. Metric Association
*Subject:* [USMA:44092] RE: 285 yottametres
On 2009/03/24, at 7:37 PM, Bill Potts wrote:
Grammatically, yes. Numerically, I don't know.
Seriously, though, if someone has provided the diameter in either
light years or parsecs, a conversion is simple arithmetic.
You realize, of course, that you may be dealing with a
hypersphere, in which case, wherever you are, you're always at the
center (or hypercenter). If that's so, I'm not sure where the
hypersurface of the hypersphere is. As a diameter is twice the
distance from the center to the surface (or hypercenter to
hypersurface), all I can do is quote Mr. Gumby (of Monty Python
fame) and say that my brain hurts.
L
Bill
------------------------------------------------------------------------
Bill Potts
WFP Consulting <http://wfpconsulting.com/>
Roseville, CA
http://metric1.org <http://metric1.org/> [SI Navigator]
*From:* [email protected]
[mailto:[email protected]] *On Behalf Of *Pat Naughtin
*Sent:* Monday, March 23, 2009 22:16
*To:* U.S. Metric Association
*Subject:* [USMA:44089] 285 yottametres
Dear All,
I wonder if you would mind checking a calculation for me.
I want to write:
'The Universe is approximately 285 yottametres in diameter.'
Is this correct?
Cheers,
Pat Naughtin
PO Box 305 Belmont 3216,
Geelong, Australia
Phone: 61 3 5241 2008
Metric system consultant, writer, and speaker, Pat Naughtin, has
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