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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
August 24, 2025
Aug. 22, 2025 — Astronomers using AI have captured a once-in-a-lifetime cosmic event: a massive star’s violent death triggered by its black hole companion. The explosion, known as SN 2023zkd, not only produced a brilliant supernova but also shocked scientists by ...
Aug. 18, 2025 — NASA and ISRO s NISAR satellite has just reached a major milestone: the successful deployment of its enormous 39-foot antenna reflector in orbit. Folded up like an umbrella during launch, the reflector is now fully extended and ready to support ...
Aug. 18, 2025 — With its two tiny CubeSats, NASA’s PREFIRE mission is capturing invisible heat escaping from Earth, offering clues to how ice, clouds, and storms influence the climate system. The insights could lead to better weather forecasts and a deeper ...
Aug. 17, 2025 — Rising CO₂ levels will make the upper atmosphere colder and thinner, altering how geomagnetic storms impact satellites. Future storms could cause sharper density spikes despite lower overall density, increasing drag-related ...
Aug. 14, 2025 — Thirteen years after landing on Mars, NASA’s Curiosity rover is running smarter and more efficiently than ever. With new autonomy and multitasking capabilities, it’s maximizing the output from its long-lasting nuclear power source while ...
July 27, 2025 — Engineers at the University of Wisconsin-Madison uncovered a critical flaw in how lunar and Martian rovers are tested on Earth. Simulations revealed that test results have been misleading for decades because researchers only adjusted rover weight to ...
July 2, 2025 — UF engineers, backed by DARPA and NASA, are perfecting laser-forming techniques that let metal sheets fold themselves into giant solar arrays, antennas, and even space-station parts right in ...
June 27, 2025 — The LSST camera at the Vera C. Rubin Observatory has released its jaw-dropping first images, each capturing 45 times the area of the full moon in one shot. Over the next ten years, this cosmic giant will scan the southern sky in ultra-HD, helping ...
June 25, 2025 — Imagine printing your Martian home from dust, sunlight, and a bit of biology. A new synthetic lichen system uses fungi and bacteria to grow building materials directly from Martian soil, completely autonomously and without human ...
June 24, 2025 — Lichen from the Mojave Desert has stunned scientists by surviving months of lethal UVC radiation, suggesting life could exist on distant planets orbiting volatile stars. The secret? A microscopic “sunscreen” layer that protects their vital ...
June 15, 2025 — AI has helped astronomers crack open some of the universe s best-kept secrets by analyzing massive datasets about black holes. Using over 12 million simulations powered by high-throughput computing, scientists discovered that the Milky Way's central ...
June 11, 2025 — By using a clever quantum approach that involves two "hands" on a clock one moving quickly and invisibly in the quantum world, the other more traditionally scientists have found a way to boost timekeeping precision dramatically. Even better, this ...
Latest Headlines
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Aug. 24, 2025 — For years, scientists thought Jupiter’s strange interior was the result of a massive collision in its youth. But new research suggests that the planet’s diffuse, “fuzzy” core wasn’t born ...
Aug. 24, 2025 — Perseverance is exploring Mars’ sandy ripples, strange frozen waves that could reveal how wind still shapes the planet. Along the way it uncovered unusual helmet-shaped rocks, sparking new ...
Aug. 24, 2025 — Astronomers have detected the closest and brightest fast radio burst ever recorded, a dazzling signal from a galaxy just 130 million light-years away. The extraordinary flash, nicknamed RBFLOAT, ...
Aug. 23, 2025 — Scientists studying asteroids found that two seemingly unrelated types share a strange dusty coating of troilite. By using polarization of light instead of traditional spectra, they uncovered ...
Aug. 23, 2025 — Earth may already be broadcasting its presence to alien civilizations without realizing it. A new study shows that our deep-space transmissions, especially those aimed at Mars and interplanetary ...
Aug. 22, 2025 — Astronomers may have uncovered the origins of the mysterious “little red dots,” some of the strangest galaxies seen in the early universe. These ...
Aug. 22, 2025 — Scientists are rethinking the universe’s deepest mysteries using numerical relativity, complex computer simulations of Einstein’s equations in extreme conditions. This method could help explore ...
Aug. 21, 2025 — A giant bubble of gas and dust surrounds the red supergiant DFK 52, likely created in a powerful outburst 4,000 years ago. Astronomers are baffled at how the star survived without going supernova, ...
Aug. 21, 2025 — Scientists from the Southwest Research Institute have found strong evidence that near-Earth asteroids Bennu and Ryugu share a common origin with Polana, a much larger asteroid in the main belt. By ...
Aug. 21, 2025 — Astronomers using the James Webb Space Telescope have uncovered a tiny new moon orbiting Uranus, increasing the planet’s moon tally to 29. The object, only about six miles wide, escaped Voyager ...