Episode 1325 · Jun 24, 2007 · 2h 36m
June 24, 2007: Dark Matter and Hubble - Richard Massey
Key Moments
Open transcriptWhat is dark matter? The million-dollar questionMassey concedes that nobody actually knows what dark matter is, but explains we know it makes up roughly 86% of the mass of the universe - six times more than every neutron, proton, and electron in the standard model combined.
Weak gravitational lensing - seeing the invisibleMassey explains the technique that lets astronomers detect dark matter: distant background galaxies act as cosmic wallpaper, and dark matter in the foreground bends their light, distorting their shapes the way a wobbly sheet of glass would.
Why ET probably isn't at our levelAsked about extrasolar planets and life, Massey accepts primitive or far-advanced life is plausible but pushes back on the idea of contemporaries: the universe is 13 billion years old, so two civilizations being within even 10,000 years of each other's development is statistically absurd.
Mapping the dark matter with HubbleMassey describes the COSMOS survey result he led: a multi-year Hubble project that pieced together a large patch of sky and produced the first 3-D map of dark matter, revealing empty voids crisscrossed by strings of dark matter with ordinary matter sitting inside those filaments.
The Bullet Cluster - dark matter passing through itselfMassey walks through the famous Bullet Cluster collision: two galaxy clusters smashed together, the ordinary gas slowed and piled up at the impact point, but the dark matter - refusing to interact even with itself - sailed straight through and ended up displaced from the visible matter.
Massey describes how dark matter forms a vast web of filaments and clumps throughout the cosmos, with enormous voids containing absolutely nothing in between. He explains that wherever ordinary matter exists, dark matter exists alongside it, drawn together by mutual gravitational attraction. The conversation covers how this invisible scaffolding shaped the formation of galaxies and ultimately made life possible.
Art also discusses the push for a national Real ID system tied to driver's licenses, noting that five states have already refused to comply and thirteen more are considering defiance. He reads new findings on the honeybee die-off spreading across 35 states, where microscopic examination reveals blackened organs and scarred intestinal tracts in the dead bees, and shares a disturbing lab analysis of substances collected after heavy rainfall that included bacteria, heavy metals, and viruses.