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
October 6, 2026
Oct. 5, 2026 NASA has selected the GIMLI project to investigate whether the Marius Hill Pit opens into a vast underground cave or lava tube. Using radar, seismic sensors, gravity measurements, and cameras, researchers will search beneath the lunar surface and ...
Oct. 4, 2026 A meteor crater buried beneath Oklahoma has turned out to be nearly 100 million years younger than scientists thought. Zircon crystals show the Ames impact occurred about 370 million years ago, meaning it was not part of the mysterious Ordovician ...
Oct. 3, 2026 Ultra-detailed simulations are showing how the first stars lit up the dark Universe and seeded space with elements such as carbon, oxygen, and iron. The MEGATRON project could bridge JWST observations of the earliest galaxies with chemical clues ...
Oct. 2, 2026 NASA’s Roman Space Telescope has demonstrated remarkable pointing stability and given its powerful planet-imaging coronagraph its first look at the cosmos. The telescope can already stay locked on a target with precision comparable to aiming a ...
Sep. 28, 2026 CosmoCube will use the far side of the Moon as a shield from Earth’s radio noise to search for a faint signal from the universe before the first stars existed. The suitcase-sized satellite could reveal how the cosmic dark ages ended and how dark ...
Sep. 28, 2026 Spaceflight may dramatically change the gut within weeks, causing bacteria to break down more protein as food moves more slowly through the intestines. The shift could help explain astronaut constipation and may have wider effects on health, making ...
Sep. 25, 2026 Scientists think beneficial fungi could help transform nutrient-poor lunar and Martian regolith into a material capable of supporting crops. By helping plants access nutrients and withstand harsh conditions, these microbes could someday make ...
Sep. 22, 2026 An amateur astronomer searching satellite maps for a Quebec camping spot accidentally discovered a massive ancient impact crater. Scientists later found shatter cones that confirmed the ...
Sep. 21, 2026 NASA’s Roman Space Telescope has successfully activated its 300-megapixel infrared camera, which will capture enormous stretches of the cosmos with Hubble-like sharpness. Its planet-hunting coronagraph is also working as expected, putting Roman ...
Sep. 18, 2026 NASA’s Roman Space Telescope may now have enough fuel for at least 22 years of science, more than double its original 10 year design life. An extremely precise course correction, extra fuel at ...
Sep. 17, 2026 A pocket-sized, roughly $100 detector can reveal the invisible stream of cosmic particles constantly passing through Earth and even through our bodies. What began as a student physics project is now being used in major experiments, balloon missions, ...
Sep. 13, 2026 Scientists have engineered yeast to turn PET plastic and agricultural waste into ingredients for protein-rich, 3D-printed cookies called µBites. Developed partly for NASA’s Deep Space Food Challenge, the system can produce proteins, fats, ...
Latest Headlines
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Oct. 6, 2026 Physicists at CERN’s Large Hadron Collider have captured the clearest evidence yet that quark-gluon plasma, the scorching-hot matter that filled the newborn universe, behaves like a true liquid. By ...
Oct. 5, 2026 October skywatchers can see Saturn at opposition, catch meteors from Halley’s Comet during the Orionid peak, and watch the Moon sweep past the ...
Oct. 4, 2026 Tiny magnetic fields created shortly after the Big Bang may help explain the long-running disagreement over how fast the universe is expanding. ...
Oct. 3, 2026 ESA’s Juice spacecraft raced past Earth on September 28, using our planet’s gravity to dramatically reshape its path toward Jupiter without burning much fuel. The flyby changed its direction by ...
Oct. 3, 2026 Scientists studying Chang’e-6 lunar soil have discovered a previously unknown magnetic mineral in natural Moon samples: a form of metallic iron called γ-Fe. Found inside tiny impact-glass ...
Oct. 2, 2026 JWST has revealed that galaxies were spreading carbon, oxygen, and other heavy elements through space just 500 million years after the Big Bang. The surprising discovery suggests the young universe ...
Sep. 30, 2026 Astronomers have found strong evidence that some mysterious, minutes-long X-ray flashes are produced when two neutron stars collide and create a magnetar. One record-setting event glowed in X-rays ...
Sep. 30, 2026 NASA’s Perseverance rover has uncovered a surprisingly complicated history of water in Jezero Crater. Scientists expected the crater’s Margin ...
Sep. 30, 2026 Powerful jets from supermassive black holes can disturb star-forming gas far beyond a galaxy’s visible edge, leaving a glowing trail hundreds of thousands of light-years long. By keeping this gas ...
Sep. 30, 2026 NASA’s SpaceX Crew-13 mission is scheduled to launch four astronauts to the International Space Station on October 1. The Dragon could reach the ...