Cosmic Mysteries

In twenty seventeen, astronomers discovered something never seen before: a small object passing through our Solar System on a trajectory that revealed it had arrived from interstellar space.
ʻOumuamua soon became famous for its strange brightness changes, tumbling motion, lack of an obvious cometary tail, and a subtle acceleration that gravity alone could not explain. Was it an unusual comet, a fragment from another planetary system, or something even stranger? This episode separates what astronomers actually observed from the speculation that followed.

For only a few milliseconds, a distant point in the universe suddenly erupts in radio waves. Then it disappears.
These events are called fast radio bursts. Thousands have now been detected, some repeating and others appearing only once. Magnetars have emerged as the leading suspects, but unusual host galaxies, strange repeating patterns, and the unknown mechanism behind the bursts suggest that the full story may be more complicated.

The universe is expanding. But when astronomers measure how fast that expansion is happening, they do not always get the same answer.
In this episode of Cosmic Mysteries, we investigate the Hubble tension, one of the most persistent problems in modern cosmology. We follow two very different ways of measuring cosmic expansion, examine why James Webb made the mystery harder to dismiss, and explore the possibility that the disagreement may be pointing toward physics we have not yet discovered.