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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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Space & Time News
June 24, 2026
June 23, 2026 SETI scientists searched the interstellar object 3I/ATLAS for radio signals that could indicate extraterrestrial technology but found nothing beyond human-made interference. Even so, the rapid-response observations helped confirm the object's ...
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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 ...
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June 24, 2026 What if consciousness isn’t limited to brains like ours? Philosophers Eric Schwitzgebel and Jeremy Pober argue that consciousness could arise in many different forms of life, even in beings built ...
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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 ...
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