The Sky at Night – Is Cosmology in Crisis ? episode 2 2019: ever since we discovered that distant galaxies are racing away from us, there has been a heated debate over just how fast the Universe is expanding. At the beginning of the 21st century, we thought we knew the answer. But now, two very different viewpoints have emerged. And they are dividing the scientific community.
The Sky at Night meets leading astronomers and cosmologists on both sides of the debate. Which team has the right answer? Or could both teams be right? If so, we may need to rethink everything we think we know about the Universe.
The Sky at Night – Is Cosmology in Crisis ?
Cosmology
Cosmology is a branch of astronomy that involves the origin and evolution of the universe, from the Big Bang to today and on into the future. According to NASA, the definition of cosmology is “the scientific study of the large scale properties of the universe as a whole.”
Cosmologists puzzle over exotic concepts like string theory, dark matter and dark energy and whether there is one universe or many (sometimes called the multiverse). While other aspects astronomy deal with individual objects and phenomena or collections of objects, cosmology spans the entire universe from birth to death, with a wealth of mysteries at every stage.
Astronomy
Astronomy is a natural science that studies celestial objects and phenomena. It applies mathematics, physics, and chemistry in an effort to explain the origin of those objects and phenomena and their evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, and comets; the phenomena also includes supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, all phenomena that originate outside Earth’s atmosphere are within the purview of astronomy. A related but distinct subject is physical cosmology, which is the study of the Universe as a whole.