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Mercury (planet)
Mercury is the innermost and smallest planet in the solar system, orbiting the Sun once every 88 days. It ranges in brightness from about −2.0 to 5.5 in apparent magnitude, but is not easily seen; its greatest angular separation from the Sun (greatest elongation) is only 28.3° (it can only be seen in twilight). Comparatively little is known about the planet: the only spacecraft to approach Mercury was Mariner 10 from 1974 to 1975, which mapped only 40 to 45 percent of the planet's surface.
Physically, Mercury is similar in appearance to the Moon as it is heavily cratered. It has no natural satellites and no substantial atmosphere. The planet has a large iron core which generates a magnetic field about 1 percent as strong as that of the Earth. Surface temperatures on Mercury range from about 90 to 700 K (-180 to 430°C) , with the subsolar point being the hottest and the bottoms of craters near the poles being the coldest.
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July 29, 2025
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 ...
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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 ...
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June 3, 2025 — Astronomers have revealed new research showing that millions of new solar system objects are likely to be detected by a brand-new facility, which is expected to come online later this ...
June 3, 2025 — Scientists have identified a new source of energetic particles near the Sun. These definitive observations were made by instruments aboard NASA's Parker Solar Probe, which detected the powerful phenomena as the spacecraft dipped in and out of the ...
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July 29, 2025 — Scientists at UC Merced have engineered artificial cells that can keep perfect time—mimicking the 24-hour biological clocks found in living organisms. By reconstructing circadian machinery inside ...
July 28, 2025 — Neutrinos, ghostly particles barely interacting with matter, may secretly be reshaping the fates of massive stars. New research suggests that as stars collapse, they form natural "neutrino ...
July 25, 2025 — In the sprawling Hydra constellation, 137 million light-years away, lies NGC 3285B—a dazzling spiral galaxy recently spotlighted by NASA’s Hubble Space Telescope. This cosmic beauty orbits the ...
July 23, 2025 — Astronomers have likely witnessed a planet forming in real time, seen inside a spiral arm of the HD 135344B protoplanetary disc—exactly where theory predicted. The direct light detection is what ...
July 22, 2025 — NASA’s Roman Space Telescope is set to embark on a deep-sky survey that could capture nearly 100,000 cosmic explosions, shedding light on ...
July 20, 2025 — A tiny object far beyond Pluto, newly discovered by the Subaru Telescope, could reshape our understanding of the early Solar System. Named 2023 KQ14, ...
July 20, 2025 — Astronomers have discovered a bizarre object in the outer solar system, 2020 VN40, that dances to Neptune’s gravitational beat in a never-before-seen rhythm. It’s the first of its kind, orbiting ...
July 20, 2025 — Astronomers studying a rare neutron star system have uncovered a surprising source of powerful X-rays. Using NASA s IXPE telescope and data from other observatories, an international team found that ...
July 20, 2025 — Astronomers have, for the first time, observed the very beginning of planet formation around a star beyond our Solar System. Using the James Webb ...
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