kjaer wrote:
> Jeg har igen læst om et forsøg med 2 synkroniserede ure, hvor det ene
> bliver fløjet rundt om jorden i et fly, og det andet bliver tilbage.
> Det skulle være bevist, at uret i flyet har gået lidt langsommere end
> det der lå fast på jorden. Er der nogen der ved hvor og hvornår det
> forsøg blev gennemført? Hvem gennemførte det? Det er lidt underlig,
> at ingen lægger navn til sådan en succes.
Der er udført en række forsøg (fra
http://www.atomki.hu/~gacsi/fizmind/specrel/experiments.html):
_Tests of the "Twin Paradox"_
/Haefele and Keating, Nature *227* (1970), p. 270 (Proposal); Science
Vol. 177 p. 166 - 170 (1972) (Experiment)./
They flew atomic clocks on commercial airliners around the world in both
directions, and compared the time elapsed on the airborne clocks with
the time elapsed on an earthbound clock (USNO). Their eastbound clock
lost 59 ns on the USNO clock; their westbound clock gained 273 ns; these
agree with GR predictions to well within their experimental resolution
and uncertainties (which total about 25 ns).
/Vessot et al, "A Test of the Equivalence Principle Using a Space-borne
Clock", Gel. Rel. Grav., *10*, (1979) 181-204; "Test of Relativistic
Gravitation with a Space borne Hydrogen Maser", Phys. Rev. Lett. *45*
2081-2084./
They flew a hydrogen maser in a Scout rocket up into space and back (not
recovered). Gravitational effects are important, as are the velocity
effects of SR.
/C. Alley, "Proper Time Experiments in Gravitational Fields with Atomic
Clocks, Aircraft, and Laser Light Pulses," in Quantum Optics,
Experimental Gravity, and Measurement Theory, eds. Pierre Meystre and
Marlan O. Scully, Proceedings Conf. Bad Windsheim 1981, 1983 Plenum
Press New York, ISBN 0-306-41354-X, p363-427./
They flew atomic clocks in airplanes which remained localized over
Chesapeake Bay, and also which flew to Greenland and back.
/Bailey et al., "Measurements of relativistic time dilatation for
positive and negative muons in a circular orbit," Nature *268* (July 28,
1977) p. 301; Nuclear Physics B 150 p.1-79 (1979)./
They stored muons in a storage ring and measured their lifetime. When
combined with measurements of the muon lifetime at rest this becomes a
highly-relativistic twin scenario (v ~ 0.9994 c), for which the stored
muons are the traveling twin and return to a given point in the lab
every few microseconds.
--
Steen Eiler Jørgensen
"No, I don't think I'll ever get over Macho Grande.
Those wounds run...pretty deep."