Scientists Baffled by a Sudden Reversal Deep Inside Earth's Core
Earth's magnetic field, the invisible shield that protects the planet from charged particles streaming from the Sun, is powered by a churning ocean of molten iron hidden thousands of kilometers beneath our feet. Although this deep interior is inaccessible, its slow-moving currents leave subtle fingerprints in the magnetic field above the surface. A new study has now revealed that one of those currents behaved in a way scientists did not expect, abruptly reversing direction beneath the Pacific Ocean and providing fresh clues about the hidden engine driving Earth's magnetic field.
The discovery challenges the long-standing view that large-scale flow in the outer core changes only gradually over decades. By combining nearly 30 years of ground-based measurements with satellite observations, researchers reconstructed how a vast region of liquid iron suddenly changed course, offering one of the clearest views yet of the dynamic processes unfolding roughly 2,200 km (1,370 miles) beneath Earth's surface.
In 2010, a broad region of iron-rich fluid deep beneath the equatorial Pacific switched from moving weakly westward to flowing strongly eastward. Scientists still do not know what triggered the reversal, but newly analyzed data from ESA's Swarm and CryoSat missions, together with observations from the German CHAMP and Danish Ørsted satellites, allowed researchers to examine the event in unprecedented detail. Published in the Journal of Studies of Earth's Deep Interior, the study combines satellite observations with ground-based magnetic measurements spanning 1997 to 2025.
These processes happen far beneath Earth's surface and do not threaten people or the climate. Even so, they are essential to understanding how the planet functions. Motion in the liquid iron outer core generates Earth's magnetic field, which helps protect the planet from charged particles streaming from the Sun. Without that shield, Earth's atmosphere and technological systems would face much greater exposure to harmful solar radiation.
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Resposta: alternativa D
Afirmação 1 — F (interpretação). O texto afirma o oposto: a corrente "switched from moving weakly westward to flowing strongly eastward" — ou seja, a inversão foi de oeste para leste, não de leste para oeste. A afirmação inverte a direção descrita no texto.
Afirmação 2 — V (interpretação). O estudo "combines satellite observations with ground-based magnetic measurements spanning 1997 to 2025", o que equivale a 28 anos — aproximadamente três décadas. A expressão "quase três décadas" é correta e coerente com o texto.
Afirmação 3 — V (gramática). "Is powered" segue a estrutura do Simple Present Passive: am/is/are + particípio passado. Aqui, "powered" é o particípio passado do verbo "to power" (alimentar/impulsionar). A tradução correta é "é alimentado" — e não "foi alimentado" (Past Passive: "was powered").
Afirmação 4 — F (gramática). "Would face" introduz uma hipótese contrafactual, não uma certeza. A estrutura "Without that shield… would face" corresponde ao Second Conditional em inglês: apresenta uma situação imaginária ou contrária à realidade atual. A afirmação erra ao classificar isso como "previsão real e esperada".
Afirmação 5 — V (gramática). "The invisible shield that protects the planet" é um aposto — mais especificamente, uma noun phrase em aposição a "Earth's magnetic field". Apostos renomeiam ou ampliam o sentido do termo anterior, funcionando em inglês exatamente como em português. A presença da oração adjetiva "that protects the planet" dentro do aposto não o descaracteriza.
These are the Top 10 emerging technologies of 2026
Fonte: World Economic Forum (adaptado) · 23 jun. 2026
The World Economic Forum's annual Top 10 Emerging Technologies report showcases the hope technology offers amid global uncertainty. This year's report, launched at the Forum's "Summer Davos" event in Dalian, China, underlines that technology is at the heart of the unprecedented change the world is undergoing — but can also offer solutions to some of the most pressing issues.
"The technologies we bring forward are chosen for their novelty, their development progress, and their potential for impact," say the authors. "Above all, they are chosen for the signals that suggest they are approaching the moment when decisions made by governments, industry, and research institutions will meaningfully shape how they arrive in the world."
Looking across the technologies the Forum's experts selected as the ones likely to make the biggest impact on our lives, three things stand out: Technologies are increasingly personal, tailored to a single patient or a specific context. Many of the solutions are decentralized in nature, producing food, energy or raw materials closer to where they are needed. They achieve more for less, whether it's space cooling without electricity, food production without animal farming, or substantially reducing the cost of traditional drug discovery.
Passive radiative cooling materials are designed to reflect 95% of incoming sunlight to keep surfaces cooler than the surrounding air — without the need for electric space cooling. They can be applied as paints, coatings, films or building components, offering a low-cost, scalable way to improve energy efficiency and reduce electricity demand. Suppliers report energy saving of up to 20% in settings such as grocery and retail stores.
Treasury wants reinvention of public sector
Fonte: BBC (adaptado)
It is incredibly bad economics to compare household finances and state finances. But occasionally it is useful, for illustrative purposes.
And today I want you to imagine what you would cut from your lifestyle if told that your income would fall by either 25% or 40%, after adjusting for inflation, over the next four years. It is quite a scary thought, isn't it?
Presumably, if you haven't done it already, you'll think about switching the weekly shop to one of those discounters. You will heat up the water for fewer hours. And the kids' swimming lessons will have to go.
But those savings would not even scratch the surface of a 40% cut. To reach that, the kids may have to share a bedroom, so you can take in a paying lodger. And the car would be history.
