More on the almost-emptiness that is black holes. Because they're invisible, they're difficult to find—but sometimes get discovered because they give off X-rays.

Even though it sounds totally crazy, astronomers are very confident that black holes exist. Our galazy is really old, it should carry at least 100 million black holes but we’ve found only a couple of dozen of them.

There's really no 'genteel' way to say it, this week we're... passing wind. But even though it's totally natural, it can be embarrassing.

It used to be thought that a pathogen (or germ) and its host develop in a 'mutually benign relationship'—this was called the 'Law of Declining Virulence'. If the common cold killed us there would be less hosts and the virus would decrease. So the common cold virus mutated to become less lethal, and more common. The Law of Declining Virulence was debunked in the 1980s, and the pathogen/host relationship is actually pretty complicated.

Power steering on a car involves various rods of steel moving relative to one another. How the rods connect is why mechanics are dealing with an unexpected problem.

Thanks to some fuzzy-looking photos, bat echolocation just got more amazing.

This program was originally published on 3 September 2019

Why do some people get headaches from eating ice-cream or drinking something very cold.

This program was originally published on 19 February 2019

It's not just their ability to run 42 kilometres that separates marathon runners from the rest of us. They've got a secret energy source in their gut.

This program was originally published on 5 November 2019

Combustion engines are marvels of engineering and power, but will they feature in the cars of the future?

This program was originally published on 8 October 2019

When a balloon pops, sometimes it leaves lots of small fragments of rubber, and sometimes it leaves just a couple of larger pieces. What's going on?

This program was originally published on 14 May 2019