First Friday Astronomy

Jupiter’s moon Io has long been famous for its sky-splitting volcanic eruptions, powered by Jupiter’s tidal gravity. But strange ridge-like features in regions adjacent to the volcanoes have raised questions since their discovery — What are they? How are they formed? Are they somehow related to the volcanoes? A recent study has argued that, even under Io’s whisper-thin atmosphere, these ridges are probably vast dune fields. This new discovery adds yet another world to our growing trove of worlds where aeolian processes operate.

Voyager’s approach to Jupiter. From https://voyager.jpl.nasa.gov/mission/science/jupiter/.
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A Hubble image of a dark knot of gas and dust called a “Bok globule”. From https://www.nasa.gov/multimedia/imagegallery/image_feature_541.html.

You may not know it, but every time you sweep your floor, you’re conducting an experiment in planet formation. The growth of dust bunnies under your broom resembles in some ways the processes of agglomeration that took place in the early Solar System and eventually produced the planets. By studying ongoing planet formation in other solar systems, we can probe the murky origins of our own Solar System. Insights from a Enlightenment-era German philosopher and World War II mathematicians, bolstered by newly bloomed mechanical desert flora, are uncovering the chaos that pervaded our Solar System’s beginnings.

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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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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 Zodiacal light, a feature that requires unusually dark skies.

Summer is the prime stargazing season. Venture out under the crystal Moon to watch Scorpius chase Orion from the sky. But if you stay within Boise’s city limits, you may find it harder to see some of your favorites. As Boise grows, so too does its footprint in the sky. However, there are many places in Idaho largely unmarred by the glare of municipal growth.

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