# Does general relativity allow an observer to view an eternity in a finite time?

@article{Hogarth1992DoesGR, title={Does general relativity allow an observer to view an eternity in a finite time?}, author={Mark Hogarth}, journal={Foundations of Physics Letters}, year={1992}, volume={5}, pages={173-181} }

I investigate whether there are general relativistic spacetimes that allow an observerµ to collect in a finite time all the data from the worldline of another observerλ, where the proper length ofλ's worldline is infinite. The existence of these spacetimes has a bearing on certain problems in computation theory. A theorem shows that most standard spacetimes cannot accommodate this scenario. There are however spacetimes which can: anti-de Sitter spacetime is one example.

## 125 Citations

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The standard theory of computation excludes computations whose completion requires an infinite number of steps. Malament-Hogarth spacetimes admit observers whose pasts contain entire future-directed,…

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- 2013

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Malament-Hogarth spacetimes are the sort of models within general relativity that seem to allow for the possibility of supertasks. There are various ways in which these spacetimes might be considered…

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- 2012

This paper introduces a wormhole based hypercomputation scenario which is free from the common worries, such as the blueshift problem, and discusses the physical reasonability of the scenario.

### Non-Turing Computers and Non-Turing Computability

- Computer SciencePSA: Proceedings of the Biennial Meeting of the Philosophy of Science Association
- 1994

These new computers serve to show that Church's thesis is a thoroughly contingent claim, and since these new computers share the fundamental properties of a TM in ordinary operation, a computability theory based on these non-Turing computers is no less worthy of investigation than orthodox computation theory.

### World of Quantum Cosmology

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- 2015

An open worldview is discussed with respect to ER = EPR [1]. Quantum states are generated by a quantum error correction code with an ancillary Hilbert space assigned to the black hole interior. These…

### Open World of Quantum Cosmology

- Physics
- 2015

An open worldview is discussed with respect to ER = EPR [1]. Quantum states are generated by a quantum error correction code with an ancillary Hilbert space assigned to the black hole interior. These…

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