Largest bacterium ever discovered has an unexpectedly complex cell

A newly discovered bacterium, Thiomargarita magnifica, challenges the definition of a microbe: its filament-like single cell is up to 2 centimetres long. T. magnifica achieves its unprecedented size by having unique cellular features: two membrane sacs. One is filled with its genetic material; the other, which is much larger, helps to keep its cellular contents pressed up against its outer cell wall so that the molecules it needs can diffuse in and out. Researchers have dubbed these sacs ‘pepins’ — inspired by the pips in fruit — and note that they blur the line between single-celled prokaryotes and eukaryotes (the group that includes humans), which pack their DNA into a nucleus.

Largest Jurassic pterosaur discovered

The largest pterosaur fossil from the Jurassic Period has been uncovered in Scotland. The new species of flying reptile, Dearc sgiathanach, lived about 170 million years ago and had a wingspan of 2.5 metres — roughly the size of an albatross. Pterosaurs evolved 230 million years ago as small reptiles and eventually grew to be massive creatures with 12-metre wingspans by the Cretaceous Period, 145 million years ago. The new fossil helps to fill a gap in this dinosaur’s history because pterosaur fossils from the Middle Jurassic are very rare.

How light is a neutrino?

Physicists are closer than ever to nailing down the mass of the elusive neutrino. A team at the Karlsruhe Tritium Neutrino (KATRIN) experiment in Germany found that neutrinos have a maximum mass of 0.8 electron volts. Researchers have long had indirect evidence that these mysterious particles should be lighter than 1 eV, but this is the first time that this has been shown in a direct measurement. The experiment has so far been able to put only an upper bound on the mass. But researchers might be able to make a definite measurement once it finishes collecting data in 2024.

Earth-like planet spotted orbiting Sun’s closest star

Astronomers have discovered a third planet orbiting Proxima Centauri, the star closest to the Sun. Called Proxima Centauri d, the newly spotted world is probably smaller than Earth, and could have oceans of liquid water.

Evidence of Europe’s first Homo sapiens found in French cave

Archæologists say they have found evidence that Homo sapiens lived briefly in a rock shelter in southern France — before mysteriously vanishing. New research suggests that distinctive stone tools and a lone child’s tooth were left by our species during a short stay some 54,000 years ago — and not by Neanderthals, who lived in the rock shelter for thousands of years before and after that time. The Homo sapiens occupation, which researchers estimate lasted for just a few decades, pre-dates the previous earliest known evidence of the species in Europe by around 10,000 years. But not everyone is convinced, and the tooth’s DNA has not been analysed to confirm its origins.

First glimpse of an isolated black hole

Astronomers have, for the first time, seen an isolated black hole, wandering unattached across the Milky Way. Lone black holes probably litter the Galaxy, but they’re extremely hard to spot because they are typically observed as they interact with other objects, such as companion stars. Confirming the black hole’s presence took ten years of observations, focusing on how the object’s extreme gravitational pull warps the light from distant stars behind it.

Direct evidence of two types of water

Water is unlike most other liquids on Earth: it has at least 66 weird properties, including high surface tension, high heat capacity, high melting and boiling points and low compressibility. Some chemists have come to think of it as not being one liquid at all, but two distinct liquid phases that coexist in a mixture. Now, physicists might have made the first direct observation of the transformation between the two states, in supercold water mixed with trehalose, a natural antifreeze that keeps the liquid from freezing.

How a disappearing ear bone turned bats into masters of echolocation

Some bats have an anatomical quirk in their ears that could explain how they evolved to hunt in specialized ways, from sensing small fish to catching insects midflight. In 2015, researchers took 3D images of the inner ear of a bat skull but couldn’t find a feature shared by almost all mammals: a bony tube that connects the ear to the brain and encases nerve cells. A more thorough search revealed many more bat species in which this bony nerve channel was missing or poked with large holes. Researchers suspect the loss of this bony channel gave the bats new hearing capabilities because the nerves are less confined.