Opposite of Black Hole - Matter Repulsion?

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SUMMARY

The discussion centers on the theoretical concept of a white hole as the opposite of a black hole. While a white hole is proposed to expel matter, it is clarified that it possesses attractive gravity rather than repulsive gravity. Both black holes and white holes are vacuum solutions characterized by zero pressure and zero energy density. To achieve a scenario with "negative pressure," one must consider a cosmological constant or a scalar field, which deviates from the vacuum state.

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  • Understanding of black hole and white hole physics
  • Familiarity with vacuum solutions in general relativity
  • Knowledge of cosmological constants
  • Basic concepts of scalar fields in physics
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  • Research the properties of black holes and white holes in general relativity
  • Study the implications of vacuum solutions in astrophysics
  • Explore the role of cosmological constants in modern physics
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Astronomers, physicists, and students of theoretical physics interested in the dynamics of black holes and the implications of negative pressure in cosmology.

Felix Quintana
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Since black holes takes matter to a singularity, theoretically could there be a hole that does the opposite? As in push everything away like negative pressure.
 
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Oh cool! Thanks!
 
Drakkith said:
A white hole, which does exactly what you proposed

Not really. A white hole has attractive gravity, not repulsive gravity. See below.

Felix Quintana said:
could there be a hole that does the opposite? As in push everything away like negative pressure.

No. A black hole, and its time reverse, a white hole, are both vacuum solutions; there is zero pressure everywhere (and also zero energy density). The white hole has things coming out of it and decelerating as they rise away. The black hole has things falling into it and accelerating as they fall. Gravity is attractive in both cases.

For a solution with "negative pressure", you need either a cosmological constant or something like a scalar field, i.e., not vacuum.
 
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