Tides

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Tides

• Paul J. Thomas
• Department of Physics and Astronomy
• UW Eau Claire

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Hopewell Rocks, New Brunswick
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The Moon Tides
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Tides
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The Moon Tides

• Every century
• the Earths day is 0.002 s longer
• the Moon is 4 m further away
• Four billion years ago
• an Earth day was 5-6 hours long
• the Moon was 20,000 km away (5 current value)

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The Moon Tides

• One billion years from now
• the Earth and Moon will be 11 spinlocked
• the Earths day will equal a lunar month (47
  current days)
• The Moon will be 526,000 km away (1.37 its
  current distance)
• The Pluto/Charon system already appears to be 11
  spinlocked.

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Galilean Satellites
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Galilean Satellites orbital periods
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Tidal Heating
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Io
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Io
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Europa
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Conamara Chaos
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Enceladus
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Extreme tides the Roche Limit
Roche Limit disruption applies to strengthless
satellites. Typically, the Roche Limit lies at a
distance of 2.4 planetary radii from the center
of a planet. (Details of satellite
density, viscosity and strength can affect this).
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All major ring systems lie within their
respective Roche limits.
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Comet Shoemaker-Levy 9
1994 July 16-22