Chris Lintott

The evening sky on Friday lit up with a bright auroral display. Such phenomena are usually confined to the polar regions, but this one was seen as far south as Mississippi and as far north as Melbourne. With word of the show spreading quickly online, and modern phone cameras capable of picking up even fainter lights in the sky, this must have been the most recorded display of aurorae in history.

My own most memorable encounter with the Northern Lights came twenty years ago, as the astronomer accompanying a party of tourists in Tromsø, Norway’s northernmost city. Even our local expert, an accomplished auroral photographer, was excited as we left the hotel just after sunset and immediately spotted a tell-tale shade of green in the sky. From our dark viewing site in the centre of a frozen lake, the view was spectacular, with the horizon lit up in bright shades of green, red and purple. The curtains of light in the sky shimmered and changed shape from moment to moment. At the climax of the display they swirled above us, creating an auroral crown and lighting the whole sky before silently vanishing.

Before the Large Hadron Collider was turned on fifteen years ago, it was suggested that the particle accelerator might bring about the end of the Universe.

Nasa’s Parker Solar Probe is now the fastest object ever built, hitting 101 miles per second as it passed within six million miles of the Sun last month, setting a record for the closest approach to our star on its tenth planned orbit. The views during its slingshots are spectacular, with Parker’s camera catching Mercury, Venus, Jupiter, Saturn, the Milky Way and the Earth sliding past the window on a recent passage. These familiar objects are seen in an unfamiliar setting. The flickering light in the background is from the Sun’s outer atmosphere, the corona, through which Parker is flying. It is the first spacecraft to enter this region of tenuous hot gas, normally only visible from Earth during the special conditions of a total solar eclipse. 

There’s a long history of astronomers looking for signs of life on Venus. Throughout the 19th century and into the 20th, reports circulated of a mysterious glow, known as the Ashen Light, which sporadically appeared on the planet’s night side. Could it be a product of civilisation, perhaps the glow of vast ritual bonfires breaking through the thick clouds that were known to blanket the planet? Later writers speculated about vast underground cities, or intelligent creatures who made the most of the thick atmosphere for aerial acrobatics. When spacecraft finally visited our neighbouring planet, in the 1960s, dreams of life on Venus receded. A runaway version of the greenhouse effect has changed what may once have been a pleasant world to a decent approximation of hell; the surface temperature is hot enough to melt lead, the pressure on the ground high enough to crush a visiting astronaut, and those thick clouds are mostly sulphuric acid. A few dreamers still wrote of floating cities in Venusian clouds, but attention turned to Mars as the best bet for searching for past or present life. Until this week, that is.

Black holes have a fearsome reputation. They have imperilled a thousand stricken starship crews in the pages of science fiction, and the language used to describe them even in non-fiction often implies menace. In popular science, they ‘lurk’ at the centres of galaxies, waiting to ‘devour’ passing stars. I’m not sure this sort of imagery is justified, though it can be hard to avoid. A lot of the time black holes are passive, quiet beasts.