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Definition of planet
The definition of "planet" has for some time been the subject of intense debate. Although the word dates back thousands of years, no officially decreed scientific definition of "planet" existed before the early 21st century. Until the beginning of the 1990s, there was little need for one, as astronomers had only a single sample of planets in solar system to study, and one small enough for its many irregularities to be dealt with individually.
However, after 1992 and the discovery of the myriad tiny worlds beyond the orbit of Neptune, the size of the sample rose from nine to at least several dozen. Following the discovery of the first extrasolar planet beyond our solar system in 1992, the number of samples has now reached hundreds. These revelations not only increased the number of potential planets, but, in their variety and peculiarity (some nearly large enough to be stars, others smaller than our Moon) challenged long perceived notions of what a planet could be.
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Space & Time News
November 3, 2025
Nov. 2, 2025 — A team of astronomers used the James Webb Space Telescope to create the first 3D atmospheric map of an exoplanet. The fiery WASP-18b, a massive “ultra-hot Jupiter,” revealed striking temperature contrasts, including regions so hot they destroy ...
Oct. 30, 2025 — Scientists have developed a groundbreaking tool called Effort.jl that lets them simulate the structure of the universe using just a laptop. The team created a system that dramatically speeds up how researchers study cosmic data, turning what once ...
Oct. 29, 2025 — Tohoku University researchers have found a way to make quantum sensors more sensitive by connecting superconducting qubits in optimized network patterns. These networks amplify faint signals possibly left by dark matter. The approach outperformed ...
Oct. 27, 2025 — Two Sydney PhD students have pulled off a remarkable space science feat from Earth—using AI-driven software to correct image blurring in NASA’s James Webb Space Telescope. Their innovation, called AMIGO, fixed distortions in the telescope’s ...
Oct. 25, 2025 — A UCLA-led team has achieved the sharpest-ever view of a distant star’s disk using a groundbreaking photonic lantern device on a single telescope—no multi-telescope array required. This technology splits incoming starlight into multiple ...
Oct. 25, 2025 — Researchers propose that hydrogen gas from the early Universe emitted detectable radio waves influenced by dark matter. Studying these signals, especially from the Moon’s radio-quiet environment, could reveal how dark matter clumped together ...
Oct. 15, 2025 — 3I/ATLAS, a mysterious interstellar object racing toward the Sun, is baffling scientists with its speed and origin. Some researchers suggest it could even be alien-made, drawing comparisons to probes ...
Oct. 14, 2025 — High above the Sun’s blazing equator lie its mysterious poles, the birthplace of fast solar winds and the heart of its magnetic heartbeat. For decades, scientists have struggled to see these regions, hidden from Earth’s orbit. With the upcoming ...
Oct. 12, 2025 — A colossal northern asteroid impact billions of years ago likely shaped the Moon’s south polar region and explains its uneven terrain. Researchers found that the South Pole-Aitken Basin formed from a glancing northern strike, revealing deep ...
Oct. 12, 2025 — ESA’s Mars orbiters have observed comet 3I/ATLAS, only the third interstellar comet ever discovered. The faint, distant object revealed a glowing coma as it was heated by the Sun. Researchers are still studying the data to understand its makeup ...
Oct. 9, 2025 — Mars may look calm, but new research reveals it’s a world of fierce winds and swirling dust devils racing at hurricane-like speeds. Using deep learning on thousands of satellite images from European orbiters, scientists have discovered that ...
Oct. 6, 2025 — ESA has inaugurated a powerful new 35-meter deep space antenna at its New Norcia site in Western Australia, marking a major boost to Europe’s ability to communicate with spacecraft exploring the ...
Latest Headlines
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Nov. 3, 2025 — Astronomers observed a massive, multi-temperature plasma eruption from a young Sun-like star, revealing how early solar explosions could shape planets. These fierce events may have influenced the ...
Nov. 2, 2025 — Spacetime isn’t something that exists; it’s a model for describing how events happen. Treating events as objects creates philosophical confusion and fuels misconceptions, such as time-travel ...
Nov. 2, 2025 — Researchers uncovered that trace compounds like nickel and urea may have delayed Earth’s oxygenation for millions of years. Experiments mimicking early Earth revealed how their concentrations ...
Nov. 1, 2025 — Astronomers have captured a haunting image of a “cosmic bat” spreading its wings across deep space. This nebula, 10,000 light-years away, glows crimson as newborn stars ignite clouds of gas and ...
Oct. 31, 2025 — The Taurid meteor shower, born from Comet Encke, delights skywatchers but may conceal hidden risks. Research led by Mark Boslough examines potential Taurid swarms that could increase impact danger in ...
Oct. 31, 2025 — Earth’s magnetosphere, once thought to have a simple electric polarity pattern, has revealed a surprising twist. New satellite data and advanced simulations show that the morning side of the ...
Oct. 30, 2025 — JWST observations show that early galaxies were chaotic, gas-filled systems rather than stable disks. Researchers from Cambridge studied over 250 galaxies and found most were turbulent, still forming ...
Oct. 30, 2025 — Two recently observed black hole mergers, occurring just weeks apart in late 2024, have opened an extraordinary new window into the universe’s most ...
Oct. 30, 2025 — In a rare global collaboration, scientists from Japan and the United States joined forces to explore one of the universe’s deepest mysteries — why anything exists at all. By combining years of ...
Oct. 29, 2025 — Rice University researchers have captured the temperature profile of quark-gluon plasma, the ultra-hot state of matter from the dawn of the universe. ...