There is a point in an Arctic winter when ordinary ideas about daytime stop being useful. The sun may skim the horizon without properly rising, snow can turn blue in the long twilight, and a clear night can suddenly fill with green light. T...
Read article
On a clear Arctic night, the sky can begin almost imperceptibly. A pale band appears above the horizon, faint enough to be mistaken for a cloud. Then it brightens. The band folds into curtai...
Read
Taste a drop of seawater and the answer seems obvious: the ocean contains salt. The more interesting question is how it got there. There are no gigantic salt deposits steadily dissolving int...
Read
Nelson Mandela did not die in a South African prison in the 1980s. He was released in 1990, became South Africa’s first Black president in 1994 and died in 2013 at the age of 95. Yet some pe...
Read
Look up on a clear night and the most obvious feature of the universe is not the stars. It is the darkness between them. That darkness seems perfectly ordinary, yet for centuries it posed a...
Read
It is one of those questions that sounds almost too simple to deserve a scientific explanation. Look up on a clear afternoon and the sky is blue. Yet that familiar color is the visible resul...
Read
Near the heart of the Milky Way lies a cloud with a reputation that sounds invented for a science-fiction cocktail menu. Sagittarius B2 contains alcohol. It also contains ethyl formate, an o...
Read
Space is a vacuum, so an astronaut cannot simply lift a visor and take a sniff. Yet crews returning from spacewalks have repeatedly described something remarkably close to a smell of space:...
Read
In the Chihuahuan Desert of northern Mexico, where Durango, Chihuahua and Coahuila approach one another across an immense dry basin, a patch of landscape has acquired one of the strangest re...
Read
In 1929, while scholars were cataloguing manuscripts in Istanbul's Topkapı Palace, they encountered a fragment of an extraordinary world map. Painted in vivid colors on parchment traditional...
Read