Reference Terms
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Planet
The International Astronomical Union defines "planet" as a celestial body that, within the Solar System that is in orbit around the Sun; has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape; and has cleared the neighbourhood around its orbit;
or within another system, it is in orbit around a star or stellar remnants; has a mass below the limiting mass for thermonuclear fusion of deuterium; and is above the minimum mass/size requirement for planetary status in the Solar System.
Our solar system is thus considered to have eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Under a separate resolution, it is also considered to have three dwarf planets: Ceres, Pluto, and Eris. There have been more than two hundred planets discovered orbiting other stars to date.
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Space & Time News
June 22, 2026
June 18, 2026 The race to build data centers in space is gaining momentum as AI drives unprecedented demand for computing power. Orbital facilities could tap into abundant solar energy and avoid many of the environmental challenges faced on Earth. Yet space ...
June 16, 2026 A new SETI study suggests we may be overlooking alien signals not because they aren't there, but because their own stars are scrambling them before they escape into space. Turbulent plasma and powerful stellar storms can spread an ultra-narrow radio ...
June 11, 2026 Scientists found that transfer learning can make the search for new physics in the universe much faster, slashing the need for expensive simulations. Yet the approach can backfire when AI relies too heavily on familiar patterns, potentially missing ...
June 10, 2026 MIT researchers have shown that one fuel can power both chemical and electric spacecraft thrusters, potentially transforming what small satellites can do. The approach combines quick bursts of speed with highly efficient long-range propulsion in a ...
June 8, 2026 NASA says a long-running air leak aboard the ISS recently worsened, leading engineers to investigate new suspected crack locations and consider a riskier repair strategy. Astronauts were temporarily moved into a safe haven as a precaution before the ...
June 6, 2026 A lightweight new X-ray telescope could finally give scientists something they’ve never had before: a complete chemical map of the Moon. Researchers used detailed mission simulations to show that a compact telescope orbiting the Moon could ...
June 6, 2026 NASA’s PExT terminal has shown that spacecraft can seamlessly communicate through multiple government and commercial networks, a major step beyond traditional single-network systems. The mission is now expanding to test new capabilities that could ...
June 5, 2026 Scientists have proposed a new method for finding tightly bound supermassive black hole pairs by searching for stars that flash repeatedly as their light is magnified by the black holes’ gravity. The timing and brightness of these bursts could ...
May 21, 2026 Mysterious red auroras spotted over Japan were found reaching astonishingly high altitudes, even during space storms considered relatively mild. The discovery suggests hidden solar activity may be ...
May 18, 2026 NASA’s Nancy Grace Roman Space Telescope is now aiming for an earlier launch in September 2026. Designed to explore dark matter, dark energy, and distant exoplanets, the telescope will capture massive, ultra-detailed surveys of the cosmos using ...
May 15, 2026 NASA is testing a next-generation space computer chip that could give spacecraft the ability to operate far more independently in deep space. The radiation-hardened processor is showing performance levels hundreds of times beyond current spaceflight ...
May 15, 2026 NASA’s Roman Space Telescope could expose a vast hidden population of neutron stars lurking unseen across the Milky Way. By detecting subtle shifts in starlight caused by gravity, the mission may ...
Latest Headlines
updated 12:56 pm ET
June 22, 2026 A colossal ancient collision may have left some of the Moon’s deepest secrets surprisingly close to future Artemis landing sites. By recreating the impact that formed the giant South Pole-Aitken ...
June 19, 2026 A distant galaxy nicknamed Shadow Blaster may have revealed a surprising source of cosmic neutrinos: extreme star formation instead of a supermassive ...
June 19, 2026 Scientists have uncovered a surprising connection between quantum gravity and an exotic quantum state of matter that could explain why the universe isn’t expanding wildly fast. The study suggests ...
June 19, 2026 Astronomers may be closing in on a long-standing cosmic mystery: why some of the universe’s biggest galaxies seem to have far fewer stars than expected. Using NASA- and JAXA-supported XRISM ...
June 18, 2026 A new theory suggests the universe is constantly recording its own history in the fabric of spacetime. If correct, this cosmic memory could help solve some of the biggest puzzles in physics, from ...
June 14, 2026 What if some black holes aren’t black holes at all? A new theoretical study suggests that when a massive star collapses, it might not form a singularity hidden behind an event horizon. Instead, the ...
June 13, 2026 Using the Keck Observatory, astronomers measured the spins of dozens of giant planets and brown dwarfs orbiting distant stars. They found that giant planets can spin faster than much more massive ...
June 13, 2026 A bold claim that the universe’s accelerating expansion was an illusion has been put to the test—and failed. Researchers found that the study behind the controversy made key mistakes when ...
June 11, 2026 NASA has selected the Artemis III crew for a high-stakes 2027 mission designed to test the future of lunar exploration. Astronauts will launch aboard ...
June 11, 2026 JWST has revealed dramatic differences between the dawn and dusk regions of the scorching exoplanet WASP-121 b. Fierce winds appear to carry heat from the planet’s permanent dayside, making the ...