gravitational lensing

Explains the proposed NASA JPL plan to use the Sun as a gravitational lens, sending solar sail craft to its focal region to image an exoplanet's surface. It covers the distances involved, how imaging with the Sun would work and the mission design.

Veritasium explains in detail how LIGO detects gravitational waves, with a laser interferometer measuring displacements smaller than a proton. The video focuses on the extreme precision and the techniques needed rather than the general discovery story.

PBS Space Time explains the proposal to use the Sun's gravity as a giant lens, sending a train of small light-sail spacecraft to the focal point roughly 550 AU out. It covers how such a telescope could image exoplanets in surprising detail and the engineering challenges involved.

Fraser Cain interviews JPL physicist Slava Turyshev about using the Sun's gravity as a lens to image distant exoplanets. They cover how the lens works, how a spacecraft would align with it, and mission design.

Veritasium explains what a black hole should look like, using J.P. Luminet's 1979 work and a cardboard 3D model to show how light bends around it. It was made just as the first black hole image was released.

PBS Space Time asks whether dark matter could be made of primordial black holes. It walks through the observational constraints that limit this idea.

A short Stanford video in which Chao-Lin Kuo surprises Professor Andrei Linde with BICEP2 evidence supporting cosmic inflation, the first apparent images of primordial gravitational waves.

A PBS Space Time episode on how gravitational wave observations of a neutron star merger, GW170817, can limit the number of spacetime dimensions. It is based on a 2018 paper.

David Kipping presents his proposed Terrascope, a telescope that uses Earth's atmosphere as a lens to achieve enormous magnification. He covers the history of telescopes and his path to the idea, plus Sol-scope and Jupiter-scope variants.

A PBS Space Time episode asking what matter, mass, and energy really are, starting with inertial versus gravitational mass and what mass-energy equivalence means.

PBS Space Time explores whether time causes gravity, explaining that gravity does not truly warp the flow of time but arises from time gradients. It revisits how gravitational time dilation works in general relativity.