On moving faster than light

Author: Gabriele Rizzo, PhD

Description: Achieving faster-than-light (FTL) travel, akin to sci-fi “warp speed,” has long been one of the dreams of the astrophysical community. However, a number of issues plague this achievement since Alcubierre’s warp drive metric in 1994, among them the need for negative energy to obtain the desired spacetime geometry and the creation of horizons around the payload. Challenges associated with the creation of horizons also include the invasion by Hawking radiation of the inside space and the stress-energy buildup on the leading horizon. Recently, an article by Lentz in Classical and Quantum Gravity offers a novel construction to avoid resorting to negative energy, moving the warp drive problem from an existential, fundamental point to an engineering issue. By overcoming the negative energy problem, it then make sense to revisit some literature about FTL astronavigation, and investigating the use of warp bubbles also for subluminal travel and not just for superluminal speed.

In this talk we will take a cross cutting view of some of the latest evolutions (Lentz 2020; Bobrick & Martire 2020) as well as some literature made relevant again (Clark, Hiscock & Larson 1999; Alcubierre & Lobo, 2017) to take stock of the progresses in warp drive spacetimes and discuss their consequences in engineering and astronavigation.