Space Science in the Twenty-First Century Imperatives for the Decades 1995 to 2015, Overview (1988) / Chapter Skim
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6. Fundamental Physics and Chemistry: Relativistic Gravitation and Microgravity Science
6. Fundamental Physics and Chemistry: Relativistic Gravitation and Microgravity Science
Pages 51-59
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From page 51... ...
The answer is decidedly positive. Spacecraft can provide a unique environment for at least two kinds of studies: those that would further our knowledge of relativistic gravitation and those exploring fundamental processes that require very small gravitational forces or very small gravitational gradients.
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From page 52... ...
The second utilizes the deflection of light passing close to the Sun. The third involves the gravitational red shift of spectral Imes, which attests to the effect of a gravitational field on the rate of clods.
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From page 53... ...
This is a nonstatic effect, and it states that rotating bodies drag nearby inertial Dames. Although the effect is exceedingly small in weak fields near solar system bodies, it might be enormous and astrophysically important near a rotating black hole.
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From page 54... ...
Observation of gravitational waves would open new astronomical windows. It would provide information about exotic sources of gravitational radiation: collapsing stellar cores, colliding neutron stars or black holes, decaying binary star systems, and rotating or vibrating neutron stars.
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From page 55... ...
The estunated sensitivity achievable with such a system is one part ~ 1022 for narrow-band periodic signals and as much as one part in 102° for transient pulses at megahertz frequencies. Such a detection shy tem offers us our best chance of directly observing the radiation produced by distant matter accelerating In strong gravitational fields such as those produced by black holes.
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From page 56... ...
Microwave ranging to the Mars Observer spacecraft to improve the accuracy of measurements of the gravitational red shift, and variation of G with time; 4. Shuttle flight of a cryogenic experiment to test the weak principle of equivalence to one part in 10~4 .
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From page 57... ...
Gravitational fields cause nonuniform ties in the distribution of matter in a given sample and can cause fragile structures to collapse. The spacecraft environment can provide a very low effective gravitational field that might provide protection from these effects.
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From page 58... ...
In a microgravity environment these ejects could be avoided, and precipitation solely under the control of diffusion could be observed. STATES FAR FROM EQUIIIBRIUM A third class of phenomena that can be observed only under conditions of low gravity are those that exhibit complex dynamical behavior as they are driven far from equilibrium.
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From page 59... ...
~ Spacecraft gravity levels and vibration spectra should be precisely measured, characterized, and displayed on those spacecraft carrying chemistry and physics experiments. ~ Strategies for producing the lowest possible gravity conditions should be considered at this tune, since experiments dealing with long-range order are open-ended in their low-gravity needs.
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