Freshly added to the library
Intermittent fasting (IF) influences not only caloric intake but also the ecosystem of the gut microbiome. Research suggests that distinct windows of eating and fasting may alter the composition and metabolic activity of these trillions of microorganisms.
The digestive system extends beyond its role in food processing. Often termed the "second brain," the gut contains a complex, autonomous network of neurons known as the enteric nervous system (ENS), which possesses the capacity to function independently of the central nervous system.
Outer space is an extremely hostile environment for the human body. The absence of breathable air, near-zero atmospheric pressure, extreme temperatures, and hazardous radiation make it impossible for humans to survive for long without a protective suit.
By definition, a vacuum is a space nearly devoid of matter. Outer space is the largest known natural vacuum, characterized by an extremely low density of matter.
The sensation of being pulled backward during acceleration or thrown forward during sudden braking is not caused by a mysterious force, but is the result of inertia—an inherent property of all objects with mass.
Each morning, the Sun does not actually "rise" from the horizon. Instead, Earth’s rotation carries our location into the sunlit region. At the equator, the planet’s surface moves at approximately 1,670 km/h, faster than most commercial aircraft. Why, then, do we not perceive this motion, and why are we not flung into space?
Wind, tides, and ocean currents are familiar Earth phenomena that profoundly influence climate, weather, and marine ecosystems. But what drives these massive movements?
Alpha Centauri is the closest star system to the Solar System, located approximately 4.37 light-years away. It is a triple star system comprising Alpha Centauri A, Alpha Centauri B, and Alpha Centauri C (Proxima Centauri). Proxima Centauri, a small red dwarf in the outermost orbit, is the closest individual star to Earth, situated about 4.25 light-years away.
Pulsar timing arrays (PTAs) recently detected an ultra-low-frequency gravitational-wave background permeating the universe. A 2026 study suggests this signal may originate not only from merging supermassive black hole binaries, but could also contain signatures of giant "dark stars" that existed over 13 billion years ago. If confirmed, these gravitational waves could help reveal the origins of the universe's earliest supermassive black holes.
By chemical composition Earth has three layers — crust, mantle and core — but the core splits into a liquid outer core and a solid inner core. Only the crust is within reach: the Kola borehole reached 12 km and never crossed the crust–mantle boundary. The rest is reconstructed from seismic waves and from rock compressed at high pressure, following USGS, NASA, IRIS and Anzellini and colleagues (2013).
An electric current is charge in motion. This article defines the elementary charge and the coulomb, retraces how the ampere moved from a force between two wires to a fixed constant, and separates conventional current direction from the direction electrons actually travel, following BIPM, NIST, NWS and NASA.
A wave carries energy, not matter. This article defines the four quantities behind every periodic wave — wavelength, frequency, period and amplitude — then uses them to separate mechanical waves from electromagnetic ones, and transverse waves from longitudinal ones, following BIPM, NASA and USGS.
