At the limits of astrophysics – with Katy Clough

Dr. Katy Clough addresses the audience at Queen Mary University of London, discussing the limits of astrophysics and presenting herself as a researcher situated between mathematics and astrophysics. She introduces her topic, hinting at the boundary between science and science fiction.

Setting the stage, Dr. Clough presents alternative titles for her talk, focusing on distinguishing between crazy and brilliant ideas in science. She mentions how historical misconceptions have often blurred the lines between the two, leading to unexpected scientific truths.

The discussion shifts to black holes, which Dr. Clough asserts are solid scientific entities despite their seemingly crazy nature. She introduces spacetime curvature, a fundamental aspect of Einstein's theory of general relativity, and illustrates how gravity operates differently in strong gravitational fields.

Using a two-dimensional model to explain spacetime, Dr. Clough elaborates on the nature of gravitational forces, emphasizing that what we perceive as gravitational attraction is actually the effect of spacetime curvature caused by massive objects like stars and planets.

Dr. Clough further illustrates spacetime curvature using an analogy involving two people walking on the surface of the Earth, explaining how their paths would converge due to the Earth's curvature. This analogy highlights the counterintuitive nature of gravity as understood through spacetime rather than traditional forces.

The talk transitions to the expansion of the universe, where Dr. Clough describes the Hubble Expansion. She explains how galaxies move apart due to the curvature of space and time rather than gravitational attraction, revealing insights into cosmic structures.

Dr. Clough dives into black holes, explaining their formation from collapsing massive stars as per Chandrasekhar's theory, which faced initial rejection due to prevailing scientific prejudices. She provides a modern confirmation of black holes through observational evidence, showcasing the first image of a black hole's event horizon.

Following her exploration of black holes, Dr. Clough introduces wormholes, describing them as theoretical shortcuts through spacetime. She discusses the challenges of conceptually and physically creating traversable wormholes due to the requirement for 'exotic matter' with negative energy, which poses several problems in modern physics.

The subject shifts to warp drives as another speculative concept from science fiction. Dr. Clough outlines how they draw from cosmological principles of space contraction and expansion while also facing challenges in terms of the need for exotic matter and potential paradoxes associated with time travel.