Dr Paul A Daniels, Guildford Astronomical Society Slide 2 Solar
System to Size Scale M any V olcanoes E rupt M ulberry J am S
andwiches U nder N ormal P ressure M any V olcanoes E rupt M
ulberry J am S andwiches U nder N ormal P ressure Marys Virgin
Explanation Made Joseph Suspect Upstairs Neighbour Marys Virgin
Explanation Made Joseph Suspect Upstairs Neighbour X 2 2 Slide 3
Background Naked-Eye Venus Historical Observations Venus Orbit The
Planet Simple Geometric Brightness Lambertian Brightness
Comparisons and Conclusions Background Naked-Eye Venus Historical
Observations Venus Orbit The Planet Simple Geometric Brightness
Lambertian Brightness Comparisons and Conclusions 3 3 Slide 4 4 4
31 st May 2011 Jupiter Mars Venus Mercury Moon Superior Conjunction
Inferior Conjunction Greatest Eastern Elongation Greatest Western
Elongation Slide 5 5 5 Greeks up to 6 th century BCE Phosphorus
(Light Bringer, Morning Star) Hesperus (Evening Star) Half-brothers
of Eos the Greek goddess of the dawn Romans up to 6 th century BCE
Lucifer (Light Bringer, Morning Star) Vesper (Evening Star)
Half-brothers of Aurora the Roman goddess of the dawn Greeks up to
6 th century BCE Phosphorus (Light Bringer, Morning Star) Hesperus
(Evening Star) Half-brothers of Eos the Greek goddess of the dawn
Romans up to 6 th century BCE Lucifer (Light Bringer, Morning Star)
Vesper (Evening Star) Half-brothers of Aurora the Roman goddess of
the dawn Slide 6 6 6 Babylonians 15 th century BCE From the Venus
tablet of Ammisaduqa we know they knew they were one object
Pythagoras late 6 th century BCE Realised that they were the same
object Wrongly thought that Venus revolved around the Earth
Babylonians 15 th century BCE From the Venus tablet of Ammisaduqa
we know they knew they were one object Pythagoras late 6 th century
BCE Realised that they were the same object Wrongly thought that
Venus revolved around the Earth Slide 7 7 7 Nicolaus Copernicus 16
th century CE Supported Heliocentric view of the Solar system Venus
orbits the Sun! Galileo Galilei 17 th century CE Observed phases on
Venus contradicts Ptolemaic system Johann Schrter 1790 CE Observed
Venuss atmosphere Nicolaus Copernicus 16 th century CE Supported
Heliocentric view of the Solar system Venus orbits the Sun! Galileo
Galilei 17 th century CE Observed phases on Venus contradicts
Ptolemaic system Johann Schrter 1790 CE Observed Venuss atmosphere
Slide 8 8 8 Orbit Parameters a= 0.72333 AU = 108,208,000 km e=
0.00678 i= 3.395 P sid = 224.701 days (Sidereal) P syn = 583.92
days (Synodic) Orbit Parameters a= 0.72333 AU = 108,208,000 km e=
0.00678 i= 3.395 P sid = 224.701 days (Sidereal) P syn = 583.92
days (Synodic) Perfect Circle Mercurys Orbit e = 0.20563 Slide 9 9
9 Go! Reset Slide 10 10 The Planet R= 6,051 km = 3,760 mi = 95% R
R= 6,051 km = 3,760 mi = 95% R M= 4.8676 x 10 24 kg = 81.5% M M=
4.8676 x 10 24 kg = 81.5% M The Atmosphere Surface temperature =
737 K = 462 C Surface pressure = 92 bar = 9.2 MPa = 90.8 x Earth
96.5% Carbon Dioxide and 3.5% Nitrogen 0.015% Sulphur
Dioxide0.0017% Carbon Monoxide 0.007% Argon0.0012% Helium 0.002%
Water Vapour0.0007% Neon Trace Carbonyl Sulphide, Hydrogen Chloride
& Hydrogen Fluoride Slide 11 11 Slide 12 12 Frames 132 &
228 : Greatest Elongation East & West Frames 156 & 204 :
Greatest Brilliancy East & West Slide 13 13 Slide 14 14 Slide
15 15 Frames 132 & 228 : Greatest Elongation East & West
Frames 148 & 212 : Greatest Brilliancy East & West Slide 16
16 The Geometric Phase Angle and timings are the ones almost
universally quoted in the literature! No mention anywhere of angles
or timings that correspond to the Lambertian analysis. Slide 17 17
What other possibilities? Im sane everyone else is mad! Difficult
to accurately measure Venus brightness? Geometric quoted so often
its taken as the only version? Answers on a postcard please Whats
Wrong? My Intuition/Assumptions? My Physics/Maths! Whats Wrong? My
Intuition/Assumptions? My Physics/Maths! Slide 18 Slide 19 Superior
Conjunction Inferior Conjunction Greatest Eastern Elongation
Greatest Western Elongation Slide 20
