In 1596, Kepler claimed that the planetary orbits would only follow "God's design" if there were two more planets: one between Mars and Jupiter and one between Mercury and Venus. Later folks came up with the Titius-Bode rule. This says there should be a planet whose orbital radius is
0.4 + 0.3 × 2ⁿ
times the distance between the Earth and Sun.
• For n = 0 we get Venus.
• For n = 1 we get Earth.
• For n = 2 we get Mars.
• For n = 3 we get... NOTHING???
• For n = 4 we get Jupiter.
• For n = 5 we get Saturn.
• For n = 6, this rule correctly predicted the location of another planet: Uranus.
So, 24 astronomers called the "celestial police" looked between Mars and Jupiter. And in 1801 one of them found a small object in the right place! Later people found other asteroids in a belt between Mars and Jupiter, but the first was the biggest: Ceres.
In 2015 we sent a probe called Dawn to investigate Ceres. It found something wonderful.
The surface of Ceres is a mix of ice and hydrated minerals like carbonates and CLAY! It probably doesn't have an internal ocean of liquid water like Jupiter's moon Europa. But it seems that brine still flows through its outer mantle and reaches the surface!
A new paper argues that Ceres contains a 𝑙𝑜𝑡 of ice, and was once an ocean-covered world:
"We think that there's lots of water-ice near Ceres surface.... People used to think that if Ceres was very icy, the craters would deform quickly over time, like glaciers flowing on Earth, or like gooey flowing honey. However, we've shown through our simulations that ice can be much stronger in conditions on Ceres than previously predicted if you mix in just a little bit of solid rock.""
https://phys.org/news/2024-09-asteroid-ceres-ocean-world-slowly.html
John Carlos Baez /
npub17u…8pd6m
2024-09-28 21:22:47
Author Public Key
npub17u6xav5rjq4d48fpcyy6j05rz2xelp7clnl8ptvpnval9tvmectqp8pd6mPublished at
2024-09-28 21:22:47Event JSON
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"content": "In 1596, Kepler claimed that the planetary orbits would only follow \"God's design\" if there were two more planets: one between Mars and Jupiter and one between Mercury and Venus. Later folks came up with the Titius-Bode rule. This says there should be a planet whose orbital radius is\n\n0.4 + 0.3 × 2ⁿ \n\ntimes the distance between the Earth and Sun. \n\n• For n = 0 we get Venus.\n• For n = 1 we get Earth.\n• For n = 2 we get Mars.\n• For n = 3 we get... NOTHING???\n• For n = 4 we get Jupiter.\n• For n = 5 we get Saturn.\n• For n = 6, this rule correctly predicted the location of another planet: Uranus. \n\nSo, 24 astronomers called the \"celestial police\" looked between Mars and Jupiter. And in 1801 one of them found a small object in the right place! Later people found other asteroids in a belt between Mars and Jupiter, but the first was the biggest: Ceres.\n\nIn 2015 we sent a probe called Dawn to investigate Ceres. It found something wonderful.\n\nThe surface of Ceres is a mix of ice and hydrated minerals like carbonates and CLAY! It probably doesn't have an internal ocean of liquid water like Jupiter's moon Europa. But it seems that brine still flows through its outer mantle and reaches the surface!\n\nA new paper argues that Ceres contains a 𝑙𝑜𝑡 of ice, and was once an ocean-covered world:\n\n\"We think that there's lots of water-ice near Ceres surface.... People used to think that if Ceres was very icy, the craters would deform quickly over time, like glaciers flowing on Earth, or like gooey flowing honey. However, we've shown through our simulations that ice can be much stronger in conditions on Ceres than previously predicted if you mix in just a little bit of solid rock.\"\"\n\nhttps://phys.org/news/2024-09-asteroid-ceres-ocean-world-slowly.html",
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