5 stories making science news this week: A Pacific 'superstructure' and an ancient Roman bullet

This week's science news has revealed an enormous "superstructure" bigger than Idaho growing on the seafloor, an ancient bullet inscribed with the name of Julius Caesar, and an extinct "hypercarnivorous" grizzly bear that was actually mostly vegetarian.

'Superstructure' growing on the Pacific seafloor since the dinosaur age

The Melanesian Border Plateau is located east of the Solomon Islands and covers an area bigger than Idaho. (Image credit: olli0815/Getty Images)

An undersea plateau in the Pacific Ocean that is bigger than Idaho first started forming with volcanic eruptions during the Cretaceous period (145 million to 66 million years ago), and it is still growing today. 

In fact, the Melanesian Border Plateau, located east of the Solomon Islands, formed through four separate pulses of volcanism, all with different root causes, according to new research. There are many hotspots in the South Pacific, so it's likely that other seamounts have been built over time in similarly complicated ways.

Earth news this week: 23 million-year-old petrified mangrove forest discovered hiding in plain sight in Panama

Peregrine mission's human remains won't reach the moon

United Launch Alliance's Vulcan Centaur rocket lifted off from Florida's Cape Canaveral Space Force Station on Monday at 2:18 a.m. EST (0718 GMT). (Image credit: CHANDAN KHANNA/AFP via Getty Images)

Private American company Astrobotic Technology launched the Peregrine spacecraft this week, with the aim of becoming the first private craft to perform a controlled landing on the moon. The spacecraft was laden with instruments to measure the conditions on the lunar surface but, controversially, also contained human remains.

Six hours into Peregrine's maiden flight, engineers reported a technical "anomaly," later discovered to be a propellant leak, leaving the mission with "no chance" of a soft landing on the lunar surface.

Also in space news this week: NASA's Parker Solar Probe gearing up for record-breaking encounter with the sun

2,000-year-old bullet found with Julius Caesar's name on it

The inscribed sling bullet that was found in Spain in 2019. One side says "IPSCA," while the other reads "CAES." (Image credit: Moralejo Ordax et al)

The discovery of an almond-shaped lead bullet inscribed with the name of Julius Caesar — likely fired from a slingshot — hints that Indigenous people in Spain supported the cause of the would-be dictator during his ultimately successful civil war more than 2,000 years ago. 

The artifact is known to specialists as a "glans inscripta" — an inscribed bullet. Measuring 1.8 by 0.8 inches (4.5 by 2 centimeters) and weighing 2.5 ounces (71 grams), the projectile was made using a mold into which molten lead was poured.

In archaeology news: Lasers reveal ancient settlements hidden deep in the Amazon rainforest

Extinct 'hypercarnivorous' grizzly bears were mostly vegetarian

California grizzly bears (Ursus arctos californicus) were similar in size to grizzlies found in Yellowstone National Park and interior Alaska today. (Image credit: Georgia Evans via Getty Images)

Extinct California grizzly bears weren't the giant, blood-thirsty "hypercarnivores" humans made them out to be, new research has found.

It turns out that the once-abundant grizzly bears were mostly vegetarian and only occasionally indulged in livestock after European colonizers and American settlers began farming in California. Contrary to popular belief at the time, these grizzlies also didn't grow to monstrous proportions and rarely, if ever, tipped the scales at the oft-cited number of 2,000 pounds (900 kilograms).

Related news this week: 1st polar bear death from bird flu spells trouble for species

'Minibrains' grown from fetal brain tissue

One of the human fetal tissue-derived minibrains, with stem cells (gray) surrounding nerve cells. (Image credit: Princess Máxima Center, Hubrecht Institute/B Artegiani, D Hendriks, H Clevers)

For the first time, scientists have grown cerebral organoids — 3D, lab-grown "minibrains" — from human fetal brain tissue.

The new organoids grew to the size of a grain of rice and contained many types of cells that self-organized into complex 3D structures. The researchers also triggered the growth of brain tumors within the minibrains and tested the tumors' response to existing cancer drugs. 

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Picture of the week

Millions of sardines washed up on the beaches surrounding Maasim on Mindanao island in the Philippines. (Image credit: Cirilo Aquadera Lagnason Jr)

Countless sardines — likely numbering in the millions — recently beached themselves on an island in the Philippines, turning coastlines silver as tiny dead fish covered the shore. Local experts say a phenomenon known as "upwelling" was likely to blame for the unusual mass stranding. 

The disoriented fish began to swim ashore early Sunday (Jan. 7) on the coastline surrounding the municipality of Maasim, on the southern tip of Mindanao island. Photos and videos captured by residents throughout the night show vast swarms of glittering sardines strewn across the beach and thrashing in the surf as they were swept onto the shore.

Sunday reading

Live Science long read

Diamonds erupt at the surface of the planet when supercontinents break up. Studying these sparkly gems can reveal secrets about our planet's deep history. (Image credit: Rory McNicol for Live Science)

In the twilight of the Cretaceous, 86 million years ago, a volcanic fissure in what is now South Africa rumbled to life. Below the surface, magma from hundreds of miles down shot upward as fast as a car on the autobahn — if that car were barreling through solid rock — chewing up rocks and minerals and carrying them toward the surface in a reverse avalanche.

What this looked like on the surface is lost to history, but it may have been as dramatic as the eruption of Mount Vesuvius. What it left behind was a series of carrot-shaped, igneous-rock-filled tubes under low, weathered white hills — and diamonds.

Formations like this are sprinkled across the globe, from Ukraine to Siberia to Western Australia, but they're relatively small and rare. Only now are we starting to discover that there is more to these "kimberlites" than precious stones — there is a tantalizing link between diamond-spewing eruptions and the destruction of supercontinents.

Editor-in-Chief, Live Science

Alexander McNamara is the Editor-in-Chief at Live Science, and has more than 15 years’ experience in publishing at digital titles. More than half of this time has been dedicated to bringing the wonders of science and technology to a wider audience through editor roles at New Scientist and BBC Science Focus, developing new podcasts, newsletters and ground-breaking features along the way. Prior to this, he covered a diverse spectrum of content, ranging from women’s lifestyle, travel, sport and politics, at Hearst and Microsoft. He holds a degree in economics from the University of Sheffield, and before embarking in a career in journalism had a brief stint as an English teacher in the Czech Republic. In his spare time, you can find him with his head buried in the latest science books or tinkering with cool gadgets.