Liquid-metal robots can melt and re-form

Researchers have created a material that can move, soften and re-harden under the influence of magnetic fields. To demonstrate the material’s promise, researchers showed how it could be manipulated to pass through barriers, extract an object from an artificial stomach, and move a tiny light bulb into place and then melt into the solder required to make it work.

What time is it on the Moon?

Scientists are working to define the first official time for the Moon. This will help to coordinate lunar missions and allow creation of a lunar satellite navigation system. Defining lunar time will involve installing at least three master clocks that tick at the Moon’s natural pace, which is slightly faster than time on Earth because the Moon has weaker gravity. The clocks’ combined output could then be synchronised to Earth time.

Has Earth’s inner core stopped its strange spin?

Around 2009, Earth’s solid-iron inner core might have stopped rotating faster than the rest of the planet. Researchers studied seismic waves generated by US nuclear test blasts during the cold war, and later by earthquakes, to discover that the inner core started spinning faster than the mantle after 1971, then slowed back down. The results could help to shine light on mysteries including what part the inner core plays in maintaining the planet’s magnetic field and in affecting the speed of the whole planet’s rotation — and thus the length of a day. But the latest study is unlikely to have the final word on the disputed topic.

Trilobites might have nose-jousted

Male trilobites of the species Walliserops trifurcatus might have used their huge trident-shaped horn in jousting matches to win females’ favour 400 million years ago. The idea is reminiscent of the modern Japanese rhinoceros beetle (Trypoxylus dichotomus), which flips opponents with its rake-like horn. The trilobite’s horn isn’t mobile enough to be an effective defence and is too long and oddly angled for foraging. And scientists have found a fossil of an adult trilobite with a deformed trident, suggesting that the structure wasn’t crucial for survival. This might be the oldest example of specialised sexual combat.

Three ‘green pea’ galaxies might have helped to end the Universe’s dark age

Astronomers using the James Webb Space Telescope (JWST) have found three tiny galaxies that could explain a watershed epoch in the history of the Universe. Reionisation was a period just 700 million years after the Big Bang when harsh radiation tore apart a ‘fog’ of hydrogen atoms hanging over the Universe, rendering stars and galaxies visible for the first time. JWST was able to observe with unprecedented clarity tiny galaxies that are so far away (and thus so old) that they were active at the time of reionisation. Three of these ancient galaxies look similar to closer ones that astronomers know well — called ‘green pea’ galaxies because of their green glow. They are prolific stellar nurseries, and emit enough energy that they might have been responsible for freeing the cosmos from its dark age.