You work at the Allen Telescope Array at the Hat Creek Radio Observatory in Northern California. It’s been a long day and it’s late. Before signing off for the day, you decide to review the latest observations, putting them through your makeshift code designed to pick out anything interesting. Then…

In the 1970s, the astronomer Vera Rubin was observing how the rotation of spiral galaxies changed as she looked along the radius, from the centre to the extreme edge. With a bit of basic Newtonian mechanics — which is sufficient for studying galactic dynamics like this, without venturing into general…

Around half a billion years after the big bang, there were six galaxies. The light from their stars began the long journey through space. For billions of years, that light was stretched by the expansion of the universe — a process known as redshift. As it travelled through the void…

Imagine you are presented with two black bags. In the first, there are 10 balls numbered 1 to 10. In the second, there are 1000 balls labelled 1–1000. You don’t know which bag contains 10 and which contains 1000. You reach into one of the bags and pull out a…

Around 1600 years ago, the Greek philosopher Hypatia had become one of the greatest minds of her generation. Not only was she a mathematician, but a philosopher, teacher and astronomer. At the same time as her students gazed into the sky, a star not that dissimilar from the Sun was…

On October 9th 2022, for only a few minutes, an incredibly bright pulse of high-energy radiation swept across the Earth. The radiation came from one of the universe’s most powerful types of explosion: a gamma-ray burst. After the Big Bang, gamma-ray bursts (GRBs) are the most energetic and luminous events…

In 1935 Albert Einstein, Boris Podolsky and Nathan Rosen made a bold but, as it turned out, incorrect claim: quantum mechanics is incomplete. At the time, it did not seem particularly controversial. After all, the argument was based on an extremely strange and troubling paradox, that particles from across the…

Four hundred million miles away from Earth, deep below a thick icy surface, there is an ocean. From behind a dark beige boulder, there’s movement. A shaded object with a dark blue ridged exterior and five appendages glides across the sea floor. The appendages move in tandem, gliding forwards, before…

Mr Smith has two children. At least one of them is a girl. What is the probability that both children are girls? If you said 1/2 then you are not correct! As you will see, the actual answer is 2/3. Bayes’ theorem describes the probability of something happening based on…