Sci-fi spaceships could create gravitational wave bursts within range of future detectors, scientists say
30 July 2024
Scientists have modelled the breakdown of alien spaceships using “warp drive” technology, to study the gravitational wave emissions that are generated.
The technology, seen in sci-fi shows like Star Trek, creates a bubble in which fictional spacecraft are propelled forward by compressing the spacetime in front of them.
The need for exotic matter with negative energy properties currently prohibits the construction of warp drives in practice.
But ripples in spacetime emitted by the bubble collapse raises the possibility of using gravitational wave signals to search for evidence of the technology elsewhere in the galaxy, according to the team from Queen Mary University of London, Cardiff University, the University of Potsdam and the Max Planck Institute (MPI) for Gravitational Physics.
Their study, published in the Open Journal of Astrophysics, highlights the importance of exploring strange new spacetimes, to (boldly) simulate what no one has seen before.
Dr Katy Clough, the study’s lead author from Queen Mary University of London, said: “Even though warp drives are purely theoretical, they have a well-defined description in Einstein’s theory of General Relativity, and so numerical simulations allow us to explore the impact they might have on spacetime in the form of gravitational waves.”
While currently confined to science fiction, physicists have explored the theoretical possibility of warp drives for decades.
Co-author Dr Sebastian Khan, from Cardiff University's School of Physics and Astronomy, said: “Miguel Alcubierre created the first warp drive solution during his PhD at Cardiff University in 1994, and subsequently worked at the MPI in Potsdam. So, it’s only natural that we carry on the tradition of warp drive research in this era of gravitational wave astronomy.”
The team studied the theoretical consequences of a warp bubble collapse or “containment failure”, using numerical simulations of the spacetime.
Unlike the chirps from merging astrophysical objects, the signal generated from a warp bubble of around 1km in size would be a short, high-frequency burst, which current detectors would not pick up.
However, future higher-frequency instruments might and, although no such instruments have yet been funded, the technology to build them exists.
In our study, the initial shape of the spacetime is the warp bubble described by Alcubierre. While we were able to demonstrate that an observable signal could in principle be found by future detectors, given the speculative nature of the work this isn’t sufficient to drive future instrument development.
The study also explores the energy dynamics of the collapsing warp drive matter, finding it to emit a wave of negative energy matter, followed by alternating positive and negative waves.
This complex dance results in a net increase in the overall energy of the system and could provide another signature of the collapse if the outgoing waves interacted with normal matter, the researchers say.
Professor Tim Dietrich from the Max Planck Institute (MPI) for Gravitational Physics and another of the study’s co-authors, added: “For me, the most important aspect of the study is the novelty of accurately modelling the dynamics of negative energy spacetimes, and the possibility of extending the techniques to physical situations that can help us better understand the evolution and origin of our universe, or the avoidance of singularities at the centre of black holes.”
Going forward, the researchers plan to investigate how the signal changes with different warp drive models and explore the collapse of bubbles travelling at speeds exceeding the speed of light.
Their paper, ‘What no one has seen before: gravitational waveforms from warp drive collapse’, is published in the Open Journal of Astrophysics.
