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Throughout their childhood, Earth and Theia lived in harmony but everything changed when gravitational disturbances attacked.

Scientists have proposed that two massive rock formations deep within Earth’s mantle, known as large low-shear velocity provinces (LLSVPs), might be the remnants of the protoplanet Theia, which collided with Earth 4.5 billion years ago to form the Moon. These formations, located beneath West Africa and the Pacific Ocean, are denser and chemically distinct from the surrounding mantle. Researchers are using new seismic and isotopic data to investigate whether Theia’s dense mantle survived and sank into Earth’s core. If true, this discovery could change our understanding of Earth’s structure and early history.

After reading the article, Marcus gained more than 529 upvotes with this comment: “I wonder where on Earth Theia hit. Is there even a way to determine this, or does the constant tectonic activity of Earth just erase that over time?” Don’t forget to share your thoughts about Theia and Earth’s mantle in the comment section below! For a long time, scientists have agreed that the Moon was formed after a protoplanet called Theia collided with the early Earth about 4.5 billion years ago. Now, a team of researchers has a new bold idea: The remains of Theia may be hidden in two massive layers of rock located deep within Earth’s mantle.

In a groundbreaking discovery, astronomers have identified an exoplanet unlike any other in our known universe. Dubbed “Cotton Candy” due to its ethereal appearance, this celestial body has left scientists baffled and intrigued.

Located in the Kepler-47-star system, approximately 1,200 light-years away from Earth, Cotton Candy orbits a binary star—a pair of stars that orbit each other. Its most remarkable feature is its unusually low density, which has led astronomers to describe it as the fluffiest exoplanet ever detected.

Cotton Candy’s density is so low that it defies our current understanding of planetary formation. According to Dr. Elena Rodriguez, lead researcher at the Galactic Exoplanet Institute, “We cannot explain how this planet formed.” The prevailing theories about planet formation involve the accumulation of dust and gas in a protoplanetary disk, eventually coalescing into a solid body. However, Cotton Candy’s density challenges this model.

Why are there atomic clocks but no nuclear clocks? After all, an atom’s nucleus is typically surrounded by many electrons, so in principle it should be less susceptible to outside noise (in the form of light). A nucleus, for high-atomic number atoms, contains more particles than does the element’s electrons. It holds nearly the entire mass of the atom while taking up only about 1/100,000th of the atom’s space. While the first atomic clock was invented in 1949, no nuclear clock has yet been feasible.

A “Little Earth Experiment” inside a giant magnet sheds light on so-far-unexplained flow patterns in Earth’s interior.

Earth’s inner core is a hot, solid ball—about 20% of Earth’s radius—made of an iron alloy. The planet’s outer core, beneath the rocky mantle, is a colder, liquid metal. Geophysics models explain that, since the movement of a liquid metal induces electrical currents, and currents induce a magnetic field, convection and rotation produce our planet’s magnetic fields. But these models typically neglect an important contribution: how Earth’s magnetic field influences the very flows that generate it. Alban Pothérat of Coventry University, UK, and collaborators have now developed a theory that accounts for such feedback and vetted it using a lab-based “Little Earth Experiment” [1]. Their results inform a model pinpointing processes that might explain the discrepancies between theoretical predictions and satellite observations of Earth, opening new perspectives on the study of geophysical flows.

Understanding flows in planetary interiors is a long-standing challenge. “If you don’t account for the fact that the magnetic field itself changes the flow, then you won’t get the right flow,” says Pothérat. Indeed, both satellite data from the European Space Agency’s Swarm mission and state-of-the-art numerical simulations indicate certain circulating core flows where liquid produced at the boundary of the inner core is fed into the outer core, moves upward toward the poles, and from there finally flows back inward (Fig. 1).

In space exploration, long-distance optical links now enable the transmission of images, videos, and data from space probes to Earth using light.

However, for these signals to travel the entire distance undisturbed, hypersensitive receivers and noise-free amplifiers are essential. Researchers at Chalmers University of Technology in Sweden have now developed a system featuring a silent amplifier and an ultra-sensitive receiver, opening up possibilities for faster and more reliable space communication.

Space communication systems are increasingly relying on optical laser beams instead of traditional radio waves, as light experiences less signal loss over vast distances. However, even light-based signals weaken as they travel, meaning that optical systems need highly sensitive receivers to detect these faint signals by the time they reach Earth. Researchers at Chalmers have developed an innovative approach to optical space communication that could unlock new opportunities—and discoveries—in space.