Science news this week: AMOC's collapse signal, the sun's galactic migration, the world's smallest QR code and oil's dying days

This week's science news was bursting with discoveries of archaeological treasures, starting with the revelation that a foundation stone for a Czech garden barn was actually a Bronze Age spearhead mold.

The mold, carved into ancient volcanic rock and dating to roughly 1350 B.C., is a relic of the ancient Urnfield culture, a late Bronze Age culture from Central Europe that's known for burying their cremated dead in urns across the Carpathian Basin and beyond. Making uniform weapons with molds such as these made armed conflict easier to sustain, while also enhancing the political and trading clout of the peoples in the region.

Yet nearly 3,000 years later, Europeans were starting to bring guns to the spearfights. That's according to the startling new discovery of Europe's oldest known portable gunpowder weapon, a handgun found in Brandenburg, Germany that dates to 1390 and could be linked to the famed siege of Kletzke Castle in the same year.

Meanwhile, in Leeds, England, a bus driver was paid a fare with a 2,000-year-old Phoenician coin that was likely minted in what is now southern Spain. Another coin discovery also popped up in Russia, amounting to roughly half a million U.S. dollars today. The hoard was found beneath a historic house and was likely buried there before the Russian Revolution in 1917.

But why hoard gold when there are feathers? Another story we covered this week described the extreme lengths a pre-Inca culture went to acquire vibrant feathers as status symbols — capturing wild parrots from the Amazon rainforest and transporting them across hundreds of miles to what is now coastal Peru.

The Gulf Stream runs AMOC

Early warning signal hidden within the Gulf Stream could signal the collapse of key Atlantic currents, study finds

The Atlantic Meridional Overturning Circulation (AMOC) brings warm weather to Europe and is a conveyer belt of carbon and nutrients across the globe. Yet while fresh water running off from Greenland's melting ice sheet is expected to sap this vital ocean current of its strength, and potentially even push it to collapse, scientists have yet to find a direct signal of this happening.

That may have all changed this week, however, with news from a new modeling study that points to a clear smoking gun for AMOC weakening — the deflection of the Gulf Stream's path farther north along the U.S. seaboard. Troublingly, satellite data shows that this shift may have already begun.

Discover more planet Earth news

—California's wildfire season is shifting, with more blazes after the traditional high-risk window, study finds

—'Blackwater' lakes and rivers in the Congo Basin are now emitting ancient carbon into the atmosphere

—Gemstone-filled river and striped mountain ridge form massive 'Y' in China's revitalized desert — Earth from space

Life's Little Mysteries

Can you see Earth's shadow?

Everything that blocks light casts a shadow, and that includes Earth itself. But where can we spot our planet's umbra? We asked some astronomers, and it turns out that, under the right conditions, you can spot Earth's shadow every day.

—If you enjoyed this, sign up for our Life's Little Mysteries newsletter

The sun's migration across the Milky Way saved life on Earth

A 'mass migration' of stars from the Milky Way's center could explain why there's life in our solar system

Our sun was born 4.6 billion years ago near the busy center of our Milky Way galaxy, but new research suggests that the existence of life on our planet is linked to a 10,000 light-year migration by our star to its current galactic suburbs.

The new study used the Gaia space telescope to analyze the ages, temperatures and composition of our sun and chart more than 6,000 stellar "twins." The results showed that our solar system's move to more sedate surroundings — away from energetic events such as supernovas — could be what gave life a chance to flourish on Earth.

Discover more space news

—'Interstellar messenger' 3I/ATLAS could be nearly as old as the universe itself, James Webb telescope observations reveal

—Universe-shaking collision of black hole and neutron star could upend our understanding of monster cosmic mergers

—Exceptionally rare sighting of planets colliding may shed light on the crash that formed the moon

Also in science news this week

—Scientists use 'negative light' to send secret messages hidden inside heat

—Generative AI can amplify and reinforce our delusions, findings show

—Scientists squished microbes into a steel 'sandwich' — and made a profound discovery about life in space

—'Rectal garlic insertion for immune support': Medical chatbots confidently give disastrously misguided advice, experts say

—Falling meteorite smashes hole in roof of German house after spectacular 'fireball' explosion over Europe

—Giant 10-person 'flying taxi' passes first flight test in China

Science Spotlight

The world is being held hostage by its reliance on oil. How can we break free from the fossil fuel?

Oil is firmly back in the news this week. Iran's blocking of the Strait of Hormuz — the world's most vital oil transit choke point — in response to the U.S.-Israel war with the Middle Eastern country has sent oil prices rocketing to over $100 a barrel.

As the global economy reels from what the International Energy Agency warned is set to be "the largest supply disruption in the history of the global oil market," Live Science investigated just how the world can free itself from the politically and environmentally disastrous fossil fuel, and found out that it could one day go the way of whale blubber.

Something for the weekend

If you're looking for something a little longer to read over the weekend, here are some of the best features, crosswords and opinion pieces published this week.

—Diagnostic dilemma: Woman born without a vagina or cervix went on to conceive a son naturally [Feature]

—Live Science crossword puzzle #33: The 'E' in E =mc^2 — 2 down [Crossword]

—AI just verified a proof that earned one of math's most prestigious prizes. Math will never be the same [Opinion]

Science news in pictures

World's smallest QR code can store data for thousands of years ‪—‬ but you need an electron microscope to see it

It may not look like much, but that's because, at least physically, it isn't.

Measuring just 3.07 × 10⁻⁹ square inches (1.98 square micrometers) and created by etching a grid onto a ceramic film using an ion beam, this is the world's smallest QR code. It is captured here by an electron microscope (the wavelengths of visible light are too thick to resolve it).

And if you're asking what the point is, rest assured that the scientists who created it aren't trying to engineer the most annoying restaurant menu in the world. Instead they think their tiny codes could be an attractive alternative to using easily overwritten magnetic tapes for long-term data storage.

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