I have not quite got there yet but surface excursions are coming soon.
One interesting aspect is what do alien planets look like ? The key to having a close terrain is a lot of rock formations a la the Riddick films, or vegetation.
Vegetation we take as life forms that use sunlight to synthesise foodstuffs. Sunlight, however, is not always what we expect.
Different solar systems have different suns. Our star is a 'G' type. The star-types which represent the best chances for having inhabitable planetary systems are F, G, K and M types.
G-type stars: emit light with a bias to the yellow part of the spectrum.
F-type stars : emit light peaking around the blue part of the spectrum. These are larger, bluer and brighter than our sun. And shorter-lived.
K-M-type stars : emit much more in the red-infra-red. These stars are samller, dimmer and longer-lived than the sun.
Other star types are not long enough lived to allow complex organisms to evolve on their planets.
The chemicals used by various organisms to take advantage of sunlight for photosynthesis vary too.
Purple anoxygenic bacteria can use light well into the infra-red. Marine aerobic cyanobacteria can use reddish light. It seems there is no limit as to the chemical innovation evolution can generate. There is no upper limit to the wavelength that can be exploited, the light spectrum of the star is the controlling factor.
Carotenoids -red-orange pigments can come into use at shorter wavelengths, exploiting bluer light. Blue cyanin compounds use the redder light wavelengths.
But it is not even this easy. An added factor is the filtration provided by the planet's atmisphere. Inhabitable planets must have liquid and gaseous water. Plus added contaminants in the atmosphere. such as ozone. The wavelengths of light arriving at the planet's surface will be modified by the atmosphere.
FOUR BASIC SCENARIOS FOR THE PLANTLIFE ON A PLANET
1)Vegetation is anaerobic and confined to the sea. The atmosphere will be dominated by methane.
2)Aerobic ocean life begins to modify the atmosphere to be less toxic and increase oxygen levels.
3)Aerobic land life : as Earth is now. Atmosphere is moderated by oxygen producers.
4)Anaerobic land life. Plants are common but do not produce oxygen.
What would the plants look like with different photosynthesising pigments ?
F and K type stars would promote a range of colours subtley different from those on Earth.
F-star planet plants would have a blue tinge as they screened out the strong blue spectrum.
K-star planets would have plants that appeared redder as they did the same screening for their red-biased spectra.
M-star planets would have plants that attempted to soak up as much light as possible and these would look black to human observers.
All this is before we consider what form the plants take....aquarium plants plus a can of spray-paint seems like the obvious answer.
All this from Scientific American April 2008 Vol 298 Number 4
Nancy Y. Kiang 'The Colour of Plants on Other Worlds'
One interesting aspect is what do alien planets look like ? The key to having a close terrain is a lot of rock formations a la the Riddick films, or vegetation.
Vegetation we take as life forms that use sunlight to synthesise foodstuffs. Sunlight, however, is not always what we expect.
Different solar systems have different suns. Our star is a 'G' type. The star-types which represent the best chances for having inhabitable planetary systems are F, G, K and M types.
G-type stars: emit light with a bias to the yellow part of the spectrum.
F-type stars : emit light peaking around the blue part of the spectrum. These are larger, bluer and brighter than our sun. And shorter-lived.
K-M-type stars : emit much more in the red-infra-red. These stars are samller, dimmer and longer-lived than the sun.
Other star types are not long enough lived to allow complex organisms to evolve on their planets.
The chemicals used by various organisms to take advantage of sunlight for photosynthesis vary too.
Purple anoxygenic bacteria can use light well into the infra-red. Marine aerobic cyanobacteria can use reddish light. It seems there is no limit as to the chemical innovation evolution can generate. There is no upper limit to the wavelength that can be exploited, the light spectrum of the star is the controlling factor.
Carotenoids -red-orange pigments can come into use at shorter wavelengths, exploiting bluer light. Blue cyanin compounds use the redder light wavelengths.
But it is not even this easy. An added factor is the filtration provided by the planet's atmisphere. Inhabitable planets must have liquid and gaseous water. Plus added contaminants in the atmosphere. such as ozone. The wavelengths of light arriving at the planet's surface will be modified by the atmosphere.
FOUR BASIC SCENARIOS FOR THE PLANTLIFE ON A PLANET
1)Vegetation is anaerobic and confined to the sea. The atmosphere will be dominated by methane.
2)Aerobic ocean life begins to modify the atmosphere to be less toxic and increase oxygen levels.
3)Aerobic land life : as Earth is now. Atmosphere is moderated by oxygen producers.
4)Anaerobic land life. Plants are common but do not produce oxygen.
What would the plants look like with different photosynthesising pigments ?
F and K type stars would promote a range of colours subtley different from those on Earth.
F-star planet plants would have a blue tinge as they screened out the strong blue spectrum.
K-star planets would have plants that appeared redder as they did the same screening for their red-biased spectra.
All this from Scientific American April 2008 Vol 298 Number 4
Nancy Y. Kiang 'The Colour of Plants on Other Worlds'
