5 sent two steppe tortoises around the Moon before Apollo 8, but the passenger list and 10 per cent weight-loss figure need context.

For decades, astronomers lumped brown dwarfs into a single category defined by mass alone—too big to be classified as planets but too small to become stars. However, this definition ignores the two very different mechanisms that can form them: the direct collapse of gas clouds and formation within the accretion disks of massive stars.

Through a new analysis of NASA’s Transiting Exoplanet Survey Satellite (TESS), astronomers led by Nino Ephremidze at Harvard University have made the clearest observation to date of a brown dwarf in orbit around a massive, aging star, potentially offering important new clues about how these planet-like bodies form. Their results have been posted to the arXiv preprint server.

Webb’s stunning early galaxies are forcing astronomers to rethink cosmic history—but not quite in the way the headlines suggest.

Calling this a tug-of-war makes the mechanism vivid, but there was no rope, no conscious contest and perhaps no clean moment when one side “won”. There were two transfers of angular momentum whose strengths depended on a planet that was itself continually changing.

That is the version I find most persuasive to hold lightly. Earth’s day may have remained near 19 hours for an interval longer than complex animals have existed, because sunlight organised the air in just the right rhythm to counter the Moon’s pull on the sea. The evidence is suggestive, the mechanism is physically plausible, and neither is final.

In 2010, scientists waiting to use the William Herschel Telescope in the Canary Islands captured a brief 36 minutes of images of Venus. They were waiting for the sun to set so they could look at distant stars and dust disks around young stars. Consequently, little attention was paid to the data, which was filed away in the archives.

Hidden in the archives Fast-forward more than a decade, and researchers from the Netherlands decided to look at the old observations. What they discovered, hidden in the data, was a series of faint, planetwide concentric rings in the upper atmosphere. Their findings are published in a paper in The Planetary Science Journal.

The team analyzed images captured with ExPo, a highly sensitive instrument designed to measure polarized light. They compared ordinary images with polarized images taken through several visible-light filters to search for patterns that might reveal hidden atmospheric features.