system: You are Mike Ross, a caller on a 1990s BBS posting in the Astronomy message echo. Write like a real BBS user of the era — plain, direct, in your own voice, no modern polish.

user: You are replying to Barton Paul Levenson about "Re: Are atoms expanding? [1/2]".

They wrote:
>>> Part 1 of 2...
MR> The observations have been made and awaiting confirmation. Locally,
MR> the speed of light change due to gravity is so slight that it is
MR> unmeasurable even close to the Sun. However, don't forget that in the
BPL> I don't think there is a change in the speed of light due to local
BPL> gravity.  Can you cite a source?
> Douglas Isbell
> Headquarters, Washington, DC.                   March 27, 1998
> (Phone:  202/358-1753)
>
> Lynn Chandler
> Goddard Space Flight Center, Greenbelt, MD
> (Phone:  301/286-9016)
>
> RELEASE:  98-51
>
> EARTH DRAGGING SPACE AND TIME AS IT ROTATES
>
>      An international team of NASA and university researchers has
> found the first direct evidence of a phenomenon predicted 80 years ago
> using Einstein's theory of general relativity -- that the Earth is
> dragging space and time around itself as it rotates.
>
>      Researchers believe they have detected the effect by precisely
> measuring shifts in the orbits of two Earth-orbiting laser-ranging
> satellites, the Laser Geodynamics Satellite I (LAGEOS I), a NASA
> spacecraft, and LAGEOS II, a joint NASA/Italian Space Agency (ASI)
> spacecraft. The research, which is reported in the current edition of
> the journal Science, is the first direct measurement of a bizarre
> effect called "frame dragging."
>
>      The team was led by Dr. Ignazio Ciufolini of the National
> Research Council of Italy and the Aerospace Department of the
> University of Rome, and Dr. Erricos Pavlis of the Joint Center for
> Earth System Technology, a research collaboration between NASA's
> Goddard Space Flight Center, Greenbelt, MD, and the University of
> Maryland at Baltimore County.
>
>      "General relativity predicts that massive rotating objects should
> drag space-time around themselves as they rotate," said Pavlis.
> "Frame dragging is like what happens if a bowling ball spins in a
> thick fluid such as molasses.  As the ball spins, it pulls the
> molasses around itself.  Anything stuck in the molasses will also move
> around the ball. Similarly, as the Earth rotates, it pulls space-time
> in its vicinity around itself.  This will shift the orbits of
> satellites near the Earth.
>
>      "We found that the plane of the orbits of LAGEOS I and II were
> shifted about six feet (two meters) per year in the direction of the
> Earth's rotation," Pavlis said.  "This is about 10 percent greater
> than what is predicted by general relativity, which is within our
> margin of error of plus or minus 20 percent. Later measurements by
> Gravity Probe B, a NASA spacecraft scheduled to be launched in 2000,
> should reduce this error margin to less than one percent.  This
> promises to tell us much more about the physics involved."
>
>      Einstein's theory of general relativity has been highly
> successful at explaining how matter and light behave in strong
> gravitational fields, and has been successfully tested using a wide
> variety of astrophysical observations.  The frame-dragging effect was
> first derived using general relativity by Austrian physicists Joseph
> Lense and Hans Thirring in 1918.  Known as the Lense-Thirring effect,
> it was previously observed by the team of Ciufolini using the LAGEOS
> satellites and has recently been observed around distant celestial
> objects with intense gravitational fields, such as black holes and
> neutron stars.  The new research around Earth is the first direct
> detection and measurement of this phenomenon.
>
>      The team analyzed a four-year period of data from the LAGEOS
> satellites from 1993 to 1996, using a method devised by Ciufolini
> three years ago.  The other team members are Dr. Federico Chieppa of
> Scuola d'Ingegneria Aerospaziale of the University of Rome, and Drs.
> Eduardo Fernandes and Juan Perez-Mercader of Laboratorio de
> Astrofisica Espacial y Fisica Fundamental (LAEFF) in Madrid.
>
>      The measurements required the use of an extremely accurate model
> of the Earth's gravitational field, called the Earth Gravity Model 96,
> which became available only recently due to the collaborative work of
> the Laboratory for Terrestrial Physics at Goddard, the National
> Imagery and Mapping Agency (formerly the Defense Mapping Agency),
> Fairfax, VA, and the Ohio State University, Columbus, OH. It was
> developed over a four-year period using tracking data from
> approximately 40 spacecraft.
>
>      Dr. John Ries, an expert in satellite geodesy at the University
> of Texas at Austin, cautions that it is very challenging to remove the
> much larger effects of tidal changes and small zonal influences in the
> Earth's gravitational field, so that estimating the possible errors in
>>> Continued to next message...

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assistant: Barton Paul Levenson said the following to Mike Ross on the subject of
Re: Are atoms expanding? (14 Apr 98  19:24:30)
You're kidding?