exoplanets

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.

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.

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.

ScienceClic explains why the rubber sheet analogy for general relativity is misleading and offers a new visualization that includes the curvature of time and shows gravity as motion through curved spacetime.

A visual scale comparison of stars and cosmic objects, from planets up to some of the largest known stars, set to music. It is meant to convey the vastness of the universe.

Veritasium explains, with expert input, that in general relativity gravity is not a force and objects follow straight paths through curved spacetime, including why standing on the ground means you are accelerating.

Cody's Lab builds a 200-billionth-scale model to show how far away the nearest stars are, using parallax and light speed. A short astronomy explainer on interstellar distances.

An Isaac Arthur episode on civilizations in the far future, past the Black Hole Era. It covers iron stars, Boltzmann brains, reversible computing and the idea of reversing entropy.

Kurzgesagt's hour-long animated film that compresses Earth's 4.5 billion year history into one hour, roughly a million years per second. It follows the evolution of life through to humanity's tiny final stretch.

Kurzgesagt explains stellar engines such as the Shkadov thruster and Caplan thruster, which could move the Sun and solar system across the galaxy over millions of years to avoid hazards and reach new regions.

A PBS Space Time episode explaining how space and time swap roles inside a black hole's event horizon. It is part of the channel's black hole series.

Physicist Angela Collier argues that dark matter is not a theory but a set of observations, covering rotation curves, the CMB and why modified gravity struggles to explain them.

An Isaac Arthur episode on civilizations in the dark, post-stellar universe, including black hole farming, accretion disks and the Penrose process as energy sources.

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.

Kurzgesagt lays out a speculative plan to terraform Venus, covering its hostile atmosphere and how it might be made Earth-like, with a sources page linked.

A minutephysics explainer showing that the Moon's path around the Sun is not a spiral but closer to a 12-sided polygon with curved corners. It argues the Moon arguably orbits the Sun rather than the Earth.

A PBS Space Time episode asking whether Venus would be a better colonization target than Mars. It covers Venus's habitable altitudes, floating balloon habitats, and the term surfacism.

Isaac Arthur surveys the popular proposed solutions to the Fermi Paradox in a 71-minute compendium. He weighs the strengths and weaknesses of each argument.

PBS Space Time explains the Hubble constant tension, in which two precise, independent methods of measuring the universe's expansion rate disagree. It covers why this calls some standard cosmology into question.

PBS Space Time introduces Miguel Alcubierre's warp drive, explaining how spacetime itself could be warped rather than moving a ship through it, and whether it is physically possible.

A PBS Space Time episode hosted by Gabe Perez-Giz on the nature of spacetime and whether space and time are fundamental. It builds up reference frames and causality in a short, dense format.

PBS Space Time explains what happens as you approach and cross a black hole's event horizon, using Penrose diagrams and light cones as the tool for understanding spacetime there.

PBS Space Time explains Stephen Hawking's prediction of Hawking radiation and how black holes can emit radiation and slowly evaporate. It goes beyond the common particle-antiparticle analogy.

Astrophysicist David Kipping presents the halo drive, a proposed way to propel a starship to a good fraction of light speed by gaining energy from a black hole. The video is based on his peer-reviewed paper and explains why energy is the main obstacle to interstellar flight.

A minutephysics explainer on why the planets orbit in a flat plane. It shows how conserved angular momentum flattens a collapsing cloud of matter into a disk.

A PBS Space Time episode asking what black holes really are and whether events can happen inside them. It covers event horizons, time dilation and common misconceptions about black holes.

PBS Space Time examines the interstellar object 'Oumuamua and the popular theories about it, including the light-sail hypothesis. It argues that a natural rock is the likeliest explanation.

Isaac Arthur examines the Dark Forest theory, Cixin Liu's proposed solution to the Fermi Paradox in which civilizations stay silent and may destroy any that reveal themselves. He tests the theory's underlying assumptions and arguments.

An Isaac Arthur episode on arcologies, self-sufficient habitats that could house whole cities, on Earth or on harsh worlds. It covers how such structures might work and what limits their size.

A short Kurzgesagt animation explaining the Great Filter, the idea that finding alien life might be bad news because it implies something usually destroys civilizations. It connects the concept to the Fermi paradox.

Terence Tao and Grant Sanderson of 3Blue1Brown walk through the cosmic distance ladder, showing how humans measured distances from the Earth to the Moon, Sun, planets and beyond. It includes animations and the history behind each step.

A PBS Space Time episode explaining the holographic principle: the idea that our 3+1 dimensional universe may be described by information on a lower-dimensional boundary. It walks through black hole entropy and the AdS/CFT correspondence.

Isaac Arthur examines the Dyson Dilemma, the puzzle of why we see no Dyson spheres or megastructures if growth-oriented civilizations should build them. He covers detectability and whether such structures could hide.

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.

A short video built around an animation of the roughly 10,000 galaxies in the Hubble Ultra Deep Field, placed at their measured redshift distances. It gives a brief history of deep field images and ends with a 3D fly-through.

Kurzgesagt introduces the Fermi paradox: with so many stars and planets, why do we see no sign of aliens? It sets up the question and what it might imply for our own future. It is part 1 of 2.

PBS Space Time explains how spacetime geometry and light cones determine the order of events and what can cause what. It visualizes causality in special relativity.

Sabine Hossenfelder explains how her opinion on dark matter has shifted, weighing the evidence for and against it and the case for modified gravity. It runs through what dark matter is and why it has not been detected.

Sabine Hossenfelder explains why she thinks faster-than-light travel may not be ruled out. She argues that the standard objections from special relativity are inconclusive.

PBS Space Time episode on the black hole information paradox, covering how black holes seem to destroy information, the no-hair conjecture and the proposed role of the event horizon. It is part of a series on black holes.