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The tidal bore in the Bay of Fundy carries billions of tons of water up the estuary at 15 km per hour, illustrating the immense power of tides. But tidal interactions in planetary systems can do more than produce killer rafting: the Earth’s tidal grip has shaped the Moon’s rotation and orbit over billions of years. But tides also power volcanoes on Jupiter’s moon Io so potent they can be seen across the Solar System and may even be the key to life in the icy moon Europa.

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Image of Sirius A and Sirius B taken by the Hubble Space Telescope. Sirius B, which is a white dwarf, can be seen as a faint point of light to the lower left of the much brighter Sirius A. From https://en.wikipedia.org/wiki/White_dwarf.

White dwarf stars have been a mystery since they were first discovered. Extraordinarily hot and compact, the engima of white dwarfs was unraveled largely through the herculean efforts of the Harvard computers. Astronomers now know white dwarfs are the final stage of a violent aging process for Sun-like stars. And though astronomers originally expected such violence would spell doom for any planets in orbit, mounting discoveries show that some planets at least can survive this cataclysmic descent into stellar senescence. Whether any life survives on those planets is another matter.

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Evading the celestial police, one Italian monk ushered in the golden age of asteroidal discovery. Once thought the remnants of a long-lost planet, asteroids are now known to have been the ingredients in the cosmic confectionaries we call planets. Though their shadows have revealed a variety of asteroids, scientists will soon get their hands on fragments of these faraway finds.

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The Tony and Pulitzer Prize-winning musical “Rent” opens with a lie.

Contrary to popular opinion, there are NOT 525,600 minutes in a year. That’s because the Earth takes more than 365 days to circle the Sun and come back to the same place (although defining “the same place” is non-trivial). Modern calendar systems assume 365.2422 days in a year, which works out to 525,948.768 minutes — it doesn’t quite roll off the tongue the same way, but it does give you almost 349 more seasons of love.

But that’s just for Earth. If you lived on one of the most recently discovered exoplanets, you would have fewer than a thousand love seasons. That’s because this planet, the ultra-hot Jupiter TOI-2109 b, circles its star once every 16 hours. But the fate of TOI-2109 b-ian lovers is sealed not just by their short seasons but because their planet is doomed, a sad destiny foretold by a French physicist who saw his own world rent to pieces.

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https://arxiv.org/abs/2011.11560

Census of planets found by NASA’s Kepler mission. From https://www.nasa.gov/content/nasa-kepler-results-usher-in-a-new-era-of-astronomy.
The famous radius gap or valley for super-Earths. From https://sites.astro.caltech.edu/~fdai/images/fulton_gap.png.
The mass-radius relationship for various assumed planetary compositions (lines) and the masses and radii of several super-Earths. From Teske et al. (2021).
Illustration of transit spectroscopy. From https://wasp-planets.net/tag/transmission-spectroscopy/.
Simulated JWST spectra for a super-Earth, TRAPPIST-1 c. From Lustig-Yaeger+ (2019).

From a sandy spit in Florida, an ear-shattering rumble followed by a sky-splitting streak of light heralded the launch of NASA’s Lucy mission, a twelve-year effort to explore sky-borne fossils. The mission began its journey to visit seven asteroids, with orbits stretching from Mars to Jupiter.

Like artifacts from someone’s childhood, Lucy’s targets will help unravel the rich and complex story of the Solar System’s earliest days. But these targets promise an even deeper glimpse than before because of exactly where they orbit. These asteroids have been trapped for billions of years in a spiderweb woven from gravity, the subtle strands of which were teased apart in 1770s Prussia by the Franco-Italian heir to Newton’s legacy.

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