From hidden water reserves that saved Earth during a planetary inferno to a star that's rewriting black hole physics, today's science news spans the cosmos and dives deep into our own biology. Discover how brain cleanup could revolutionize epilepsy treatment, why a protein in your gut might treat depression, and the "extinct" fish that just came back from the dead.

During Earth's violent youth, when the entire planet was a molten hellscape, life shouldn't have stood a chance. Yet here we are. Scientists have now discovered the secret: a massive underground water reservoir that acted as Earth's hidden insurance policy.

The research reveals that deep within Earth's mantle, water remained locked away in minerals and rocks, protected from the surface inferno that sterilized the planet multiple times. This subterranean vault slowly released water over millions of years, replenishing the oceans and creating conditions for life to emerge.

Why this matters: Understanding Earth's water cycle during extreme planetary events helps scientists identify which exoplanets might harbor life. If underground water reserves can preserve habitability through catastrophic surface conditions, we may need to expand our search for life beyond just planets with visible oceans. This discovery also provides insights into how Earth could recover from future extreme climate scenarios.

Astronomers have spotted a star behaving in ways that directly contradict our understanding of how objects should act near black holes. The strange stellar object is orbiting dangerously close to a supermassive black hole, yet its characteristics defy the extreme gravitational and radiation effects that should be tearing it apart or dramatically altering its composition.

The discovery challenges fundamental models of stellar behavior in extreme gravitational environments. Researchers observed properties that shouldn't be possible given the star's proximity to the black hole's event horizon, suggesting either our models of black hole physics are incomplete or this star has unique protective mechanisms we've never encountered before.

This finding could reshape how we understand the extreme environments around black holes and may reveal new physics operating under conditions we can't replicate on Earth. It also raises questions about what other unexpected phenomena might exist in these cosmic laboratories where gravity and energy reach their most extreme states.

Scientists have identified a protein in the gut that directly influences depression, opening an entirely new avenue for treating mental health conditions. This discovery strengthens the emerging understanding of the gut-brain axis and suggests that depression treatment might not need to focus solely on the brain.

The research demonstrates that this specific protein acts as a key communicator between the digestive system and brain chemistry. When its levels or function are disrupted, depressive symptoms can emerge. The mechanism provides a biological explanation for why gut health and mental health are so closely linked, validating what many researchers have suspected but struggled to prove.

Why this matters: Current antidepressants work for only about 60% of patients and can take weeks to show effects. A gut-based approach could offer faster relief with fewer side effects, since targeting the digestive system might avoid many complications of brain-focused medications. This could particularly help patients who don't respond to traditional antidepressants or experience severe side effects from them.

In a surprising twist, researchers have found that cleaning up accumulated cellular debris in the brain not only reduced epileptic seizures but also restored lost memory function. The discovery reveals that brain "housekeeping" plays a far more critical role in neurological health than previously understood.

The study focused on the brain's waste removal systems, which can become overwhelmed or dysfunctional in epilepsy patients. When researchers enhanced this cleanup process, they observed a dramatic reduction in seizure frequency and severity. Even more remarkably, patients showed improvements in cognitive function, suggesting the accumulated debris had been interfering with normal neural signaling.

This approach could revolutionize epilepsy treatment, which currently relies heavily on medications that suppress neural activity but don't address underlying causes. A cleanup-based therapy could potentially help the roughly 30% of epilepsy patients who don't respond to existing drugs. The memory restoration component also suggests applications for other neurological conditions where cognitive decline accompanies the primary symptoms.

A fish species declared extinct has been rediscovered thriving in a remote Bolivian pond, offering hope that other species we've written off might still be clinging to survival in overlooked habitats. The discovery came more than two decades after the last confirmed sighting.

The rediscovery highlights how species can persist in isolated pockets of habitat, even when they've disappeared from their known range. The remote pond where researchers found the fish had been largely unexplored, suggesting that comprehensive biodiversity surveys in hard-to-reach locations could reveal more "Lazarus species" that have actually been hiding rather than extinct.

This find is particularly significant for conservation efforts, as it demonstrates the importance of protecting potential refuge habitats even when target species haven't been recently observed there. It also serves as a reminder that declaring extinction requires extremely thorough documentation, and that absence of evidence isn't always evidence of absence in biodiversity research.

A common food ingredient consumed during childhood may have profound and lasting effects on health that persist into adulthood, according to new research that reveals how early dietary choices create biological imprints with lifelong consequences.

The study shows that this ingredient influences developmental processes during critical growth periods, affecting everything from metabolic function to immune system development. These changes become embedded in the body's regulatory systems, meaning childhood exposure creates health trajectories that can be difficult to alter later in life, even with dietary modifications.

The implications for public health policy are significant. If common food ingredients have such lasting impacts, childhood nutrition guidelines may need substantial revision. Parents and policymakers now have evidence that early dietary interventions aren't just about immediate health but about establishing foundations that influence disease risk, metabolism, and wellbeing for decades to come.

From the cosmos to our cells, today's discoveries remind us that science continues to reveal hidden connections and unexpected mechanisms. Each finding opens new questions: What other secrets lie in Earth's depths? What physics awaits discovery in extreme environments? How many more connections exist between our body systems? The answers are being written in laboratories and observatories right now.