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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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Dec. 6, 2025 SQUIRE aims to detect exotic spin-dependent interactions using quantum sensors deployed in space, where speed and environmental conditions vastly improve sensitivity. Orbiting sensors tap into ...
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Dec. 2, 2025 A UC Irvine team uncovered a never-before-seen quantum phase formed when electrons and holes pair up and spin in unison, creating a glowing, liquid-like state of matter. By blasting a custom-made material with enormous magnetic fields, the ...
Nov. 23, 2025 A massive solar storm in May 2024 gave scientists an unprecedented look at how Earth’s protective plasma layer collapses under intense space weather. With the Arase satellite in a perfect observing position, researchers watched the plasmasphere ...
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Dec. 30, 2025 Thanks to Einstein’s relativity, time flows differently on Mars than on Earth. NIST scientists have now nailed down the difference, showing that Mars clocks tick slightly faster—and fluctuate ...
Dec. 29, 2025 Mars isn’t just dusty—it crackles with electricity. Scientists discovered that dust devils can generate tiny electric sparks, captured for the first time by Perseverance’s microphone. These ...
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Dec. 27, 2025 A newly identified region on Mars may hold the key to future human landings. Researchers found evidence of water ice less than a meter beneath the surface, close enough to be harvested for water, ...
Dec. 27, 2025 New observations reveal that the relationship between ultraviolet and X-ray light in quasars has changed over billions of years. This unexpected shift suggests the structure around supermassive black ...
Dec. 26, 2025 Astronomers have decoded the hidden past of a distant red giant star by listening to tiny vibrations in its light, revealing clues of a dramatic cosmic history. The star, which quietly orbits a ...