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    What Is the Sun Made Of and When Will It Die?

    Reprinted with permission from Quanta Magazine’s Abstractions blog. Like any star in its prime, the sun consists mainly of hydrogen atoms fusing two by two into helium, unleashing immense energy in the process. But it’s the sun’s tiny concentration of heavier elements, which astronomers call metals, that controls its fate. “Even a very small fraction […]

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    I Built a Stable Planetary System with 416 Planets in the Habitable Zone

    This system is completely stable—I double-checked with computer simulations. But nature would have a tough time forming this system. If it exists, it could only have been built by a super-advanced civilization.Image by Sean Raymond / planetplanet.net When Frank Drake was a boy, growing up in 1930s Chicago, his parents, observant Baptists, enrolled him in […]

  • Annular eclipse

    The Search for Eclipses as Perfect as Earth’s

    This classic Facts So Romantic post was originally published in September, 2013. Roughly twice a year, the apparent positions of sun and moon coincide, and a fortunate few observers are treated to a solar eclipse. Watching such an event provides the opportunity to contemplate a strange coincidence: From the surface of Earth, the apparent sizes […]

  • Nebra Sky Disk

    The Amazing Sky Calendar That Ancients Used to Track Seasons

    The Nebra Sky Disk photographed in Basel, Switzerland, in 2006Dbachmann via Wikipedia   Henry Westphal is tired. It’s July 4, 1999, a Sunday. He and a friend are climbing the Mittelberg or “Central Hill,” a small mountain near Nebra, in central Germany. Both men know of ancient ruins located here. Equipped with two metal detectors, […]

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    Imagine a World With One Universal Time Zone…

    A warped photo of Big Ben. Alan Cleaver via Flickr Earlier this month, the chief minister of the Indian state of Assam, Tarun Gogoi, started something of a brouhaha with a bold pronouncement on the generally sleepy topic of time zones. “We need a local time for Assam and the other northeastern states which will […]

  • Allen_HERO

    Our Prodigal Sun

    Searching the heavens for our sun’s family.

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    Hunting for Eclipses as Perfect as Earth’s

    Roughly twice a year, the apparent positions of Sun and Moon coincide, and a fortunate few observers are treated to a solar eclipse. Watching such an event provides the opportunity to contemplate a strange coincidence: From the surface of Earth, the apparent sizes of the Sun and Moon in the sky are nearly equal. The […]

  • solar system model

    Two Good Ways to Really *Get* the Solar System

    The Sun is one busy celestial body. In addition to giving us light, holding the solar system together, and providing the energy for almost every living thing on Earth, it’s also a grapefruit in a grass field in Austin, Texas, and a 50-foot yellow archway in northern Maine. Now, obviously this huge mass of incandescent gas […]