Old Mars

1
Old Mars

• Mars is further away, we see a smaller image so
  we
• need much better telescopes

2
Mars

• Reddish color, easily seen with naked eye
• on Earth, red colored rocks are found in deserts
• Roman god of war color of blood (second to
  Jupiter)
• Astrological symbol is a shield and spear

3

• Until photography, all images drawn or painted
• very difficult to compare observations -
  intervention of the observer
• first image due to Fontana (1636)

4
Refractor telescopes

• Simple refractor
• not a sharp image
• colors have a
• different focus

5
(No Transcript)
6

• First accurate drawing - Huygens 1659
• first showing of polar caps Huygens 1672
• Mars was seem to have dark and light areas
• Dark water (oceans, seas, bays lakes)
• Bright continents (reddish color)

7
Syrtis Major
8
1672
9

• Herschel 1777-1784
• observed tilt to be 30 degrees (like Earth)
• therefore, 4 seasons (like Earth)
• concluded that the inhabitants would enjoy a life
  similar to that on Earth

10
Big improvement

• Invention of the achromatic objective lens
• Chester Hall, 1729
• Two different kinds of glass in the objective

11
Problems with glass

• 1799
• Swiss, Pierre Louis Guinand
• cast high quality lenses as large as 6
• worked with Joseph von Fraunhofer, a German
  optician who did the grinding and polishing
• later lenses were much larger

12
Applications of new telescopes

• Heinrick Mädler - school teacher (seminary),
  amateur astronomer
• met Wilhelm Beer - banker and amateur astronomer
• looked at Mars (map in 1830)
• did not name features
• mapped Moon 1834-1836

13
(No Transcript)
14
More observations

• Mountains of Mitchell, 1845 (B M)
• use of the term canale Angel Secchi, 1858
  (referred to a channel)
• Dawes, 1860s, names features
• also determines relation between size of
  telescope and resolution
• begins a race for big telescopes
• No standard nomenclature

15
(No Transcript)
16
Next opposition

• 1877
• new telescope (Alvan Clark) 26 at US Naval
  Observatory
• new observer Asaph Hall
• not a professional astronomer
• observed two satellites Phobos (fear) and Deimos
  (flight) - reference to Iliad
• only terrestrial planet (except Earth) with
  satellites

17
At the same opposition

• Giovanni Schiaparelli
• accurate measurements of lat. long. of features
• introduced a nomenclature that stuck (1877)
• showed long, straight, narrow dark makings
• called them canali, again meaning channels
• got translated into canals, artificial

18
(No Transcript)
19
New features

• Schiaparelli - observed gemination, a splitting
  of canals
• canals had to be several miles wide to be seen
• must have been vegetation on the banks of the
  canals
• showed dark areas where canals crossed

20
(No Transcript)
21
Names

• Light areas - terrestrial or imaginary lands
• Arabia, Hellas, Syria, Amazonis
• dark areas - bodies of water
• seas - Tyrrhenum mare
• bays - Sabaeus sinus
• gulfs - Golfo sabeo
• lakes - Solis lacus

22
(No Transcript)
23
Problems in viewing Mars

• Opposition every 2 years and 50 days
• best oppositions every 15 or 17 years
• difficult image at opposition
• next (great) opposition August 28, 2003
• Best in thousands of years!

24
(No Transcript)
25
(No Transcript)
26
(No Transcript)
27
New player

• Percival Lowell 1855-1916
• an amateur but a serious one
• was convinced that the canals were artificial
• constructed to irrigate deserts (red color)
• view of Mars as a planet drying out
• Dark areas were not seas but marshes
• Wave of darkening (primary evidence)

28
If there is water on Mars

• Dark areas, light areas (yes)
• clouds (yes)
• storms (yes)
• reflection of Sun on water (no)
• Reflected light not polarized (no)
• but suppose the dark areas are vegetation
• polar caps (yes)
• red color (yes)

29
Implications of water

• On Earth, water comes from volcanic activity
• volcanoes indicate geologic activity
• volcanoes indicate plate tectonics
• moderate temp. atmospheric pressure
• as we understand it, life can form under these
  conditions

30
General conclusions, 1877

• Moderate climate
• water available
• large desert areas
• planet losing water
• an ideal place for life
• sentient organisms living there

31
Requirements for life

• Moderate temperatures (between 0 and 100 C)
• free water
• an atmosphere
• does not have to be oxygen