Sunday, 24 May 2015

In The Space Near A Black Hole

Poul Anderson, Starfarers (New York, 1999).

In the accretion disk, temporary concentrations of plasma, possibly shock-wave resonance effects, may form plasmoids, with the masses of large asteroids, in the flares. Such a plasmoid could be massive enough to deflect a scientific observation station from its intended orbit.

The station must round periastron (p. 333) and raise the apastron (p. 334). Readers without a scientific background gather some idea of the meanings of such terms from the contexts in which they are used in sf. However, it is worthwhile to check and get a clearer understanding.

A premise of Starfarers is that nothing that enters a black hole can re-emerge from it because the escape velocity of the collapsed star is greater than the speed of light. However, would an FTL craft be able to enter and leave? A frequent premise of "hyperspace" is that it cannot be used too deep inside a gravity well. However, James Blish's spindizzy-powered spaceships and flying cities have their own internal gravitational fields that are independent of the gravity of the external universe so would they have been able to travel around safely inside black holes and even into and back out of singularities if Blish had known of black holes when he wrote Cities In Flight?

Anderson shows that interstellar explorers have a great deal to contend with even before they encounter any extrasolar intelligences.

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