Science and Creationism 4. Planetary Science © Colin Frayn,

© Colin Frayn, The Heavy Elements in Planets Where did they come from? –Heavy element fusion in massive stars –Supernova explosions Why are they not all at the centre? –It’s likely that many heavy elements are in the planet cores –Some are not Recycled in magma, ejected in volcanism Fixed in the solid crust

© Colin Frayn, Cooling Planets Are the planets radiating heat too quickly? –Incoming heat flux from sun is less than heat radiation from planet –Net cooling effect Jupiter –Heat loss is very slow It is still radiating heat from its formation Saturn –Heat loss is slightly too fast Heat is gained from gravitational energy of helium precipitation An unusually low upper atmospheric abundance of Helium is observed –This gives strength to the theory

© Colin Frayn, Saturn’s Rings How did they form? –Probably from the disintegration of a satellite (moon) or comet How old are they? –It was believed that they were 100 million years old –New observations from Cassini suggest that they are much older Particle ‘recycling’ gives impression of young ring age Rings could be the same age as the solar system They may be debris from the planet’s formation –Even if they were young, it’s not a problem!

Helium 98% of Sun is Hydrogen & Helium <1% of inner planets is H, He Why is this? Hydrogen and Helium are the two lightest elements –They move more quickly than heavier elements –They are harder to capture –Requires a larger gravitational ‘well’ H and He in inner solar system would have been expelled by solar wind © Colin Frayn,

© Colin Frayn, Recession of the Moon The moon is receding (moving away) at a rate of 3.8cm per year –This is no problem for the age of the Earth-Moon system –Often much faster (incorrect) rates are claimed Also, the rate of recession is much faster now than it has been –Observation of tidally laminated sediments shows us the moon’s orbital period over evolutionary time –Mean recession rate of 2.16 cm/yr over the last 650 Myr –Between 2.5Gyr and 650Myr, mean rate was 1.27 cm/yr

© Colin Frayn, The Earth’s Magnetic Field Earth’s magnetic field strength is falling –If you follow backwards in time, it would have been too high a few thousad years ago This is based on: –Obsolete models of the Earth’s interior The Earth’s magnetic field is generated by a dynamo effect It is not a simple, decaying field –Incorrect (or unsupported) extrapolation from data There’s insufficient evidence to fit an exponential decay –Incorrect assumptions about the cause of the reduction It is periodic, not monotonical decay Magnetic reversals regularly occur

© Colin Frayn, Moon Dust Why is there not more lunar dust? –How much should we expect? Hans Pettersson, February 1960, Scientific American Claimed an upper estimate of 39,000 t/d of dust falling on Earth –Some creationists still use this massively incorrect figure today! Overestimated by a factor of 1,000! –Correct value (30-40 t/d) known since 1972 (Dohnanyi) –How much dust did NASA expect? Very little: “In 1965, a conference was held on the nature of the lunar surface. The basic conclusion of this conference was that both from the optical properties of the scattering of sunlight observed from the Earth, and from the early Ranger photographs, there was no evidence for an extensive dust layer.” S. Shore, 1984

© Colin Frayn, The Vapour Canopy A vapour canopy above the Earth –How could this avoid gravity? The Meissner Effect –Sometimes incorrectly spelled ‘Mysner’ –This is irrelevant: It only applies to superconductors! –i.e. not the Earth Water would condense and fall as rain –It couldn’t remain up there for 1,500 years!