Text 28678, 60 rader
Skriven 2007-05-07 10:52:06 av John Hull (1:123/789.0)
     Kommentar till en text av VERN HUMPHREY (1:123/140)
Ärende: Muslems
===============
VERN HUMPHREY -> JOHN HULL wrote:
 VH>>> It would take over 58 years to reach light speed (if we could)
 VH> and just
 VH>>> as long to decelerate from that speed so we could land.  A
 VH> child born
 VH>>> just after takeoff would be 117 years old when he reached his
 VH>>> destination -- assuming there was no period of travel at light
 VH> speed
 VH>>> between acceleration and decelerations

 JH>> Except that it wouldn't take that long simply because the nearest
 VH> star is
 JH>> closer than that,

 VH> The nearest star is about 10 light years away.  To reach that star
 VH> (which doesn't have much in the way of interest) would take more than a
 VH> lifetime.

 JH>> you are limiting your engine size,

 VH> How am I limiting my engine size?  I haven't even mentioned engine size.

 VH> If you mean the assumption of 1G acceleration, that's because at much
 VH> below 1G we get osteoporesis and it takes longer to get there, and at
 VH> much over 1G we overstress the astronaut's heart and internal organs.
 VH> At 2G for example, a 180 lb astronaut would weight 360 lbs -- and you
 VH> know the life expectancy of people who weight that much?

 JH>> and you don't know how
 JH>> what the actual result of nearing light speed will be.

 VH> Yes, we do -- as we near the speed of light, the mass of the vehicle
 VH> approaches infinity, and the energy needed to accelerate exceeds the
 VH> amount of energy in the universe.

 JH>> I found two differen
 JH>> websites that both agree we could travel to the nearest start and
 VH> return in
 JH>> about one lifetime on earth, but it would be considerably less for the
 JH>> travelers due to time dilation effect.

 VH> I've found websites that say Al Gore should be president and that he'd
 VH> make a good one. :-)
Are you implying I can't tell the difference?  Physics is no different than any
other scientific field in that there are different theories and camps that
support them.  Wasn't too many years ago that top geologists discounted
continental drift; and only a few years ago, James Bakker was almost run out of
paleontology for his theories about dinosaurs being warm blooded and nurturing.
 Both of those ideas are now accepted by virtually all scientists in those
fields.  There is much more we don't know about physics than we do.  I choose
not to be so foolish as to discount something out of hand that hasn't been
proven wrong OR right yet.

-- 
John
..
My Blog: Mad Gorilla's Jungle:      http://madgorilla.terapad.com/

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