Upload
others
View
10
Download
0
Embed Size (px)
Citation preview
Atmosphere of Venus Mars and EarthAtmosphere of Venus, Mars and Earth
Yoshihide Kozaios de o a
2009 Asian Science Camp
August 3
The Earth from the MoonThe Earth from the Moon
VenusVenus
MarsMars
JupiterJupiter
• Orion NebulaWhere stars are bornWhere stars are bornDistance 1500light Years 50 light year Wide(3 million AU)( )Stars are born whereD it f i t t llDensity of interstellarMatter is high.
Chemical Composition of AtmosphereChemical Composition of Atmosphere
Ch i l iti f t h (%)• Chemical composition of atmosphere(%)• N2 O2 CO2 H2O H2 He• Venus 3 4 0 007 96 0 019Venus 3.4 0.007 96 0.019 • Earth 78 21 0.037 1~2.8• Mars 2.7 0.13 95 0.03• Jupiter 89 11
• Surface pressure Temperature Solar distance• Venus 90 atm. 460˚C 0.72 AU
E th 1 20˚C 1 00• Earth 1 20˚C 1.00• Mars 0.006 ‐60˚C 1.52
Greenhouse EffectGreenhouse Effect
High temperature of Venus is caused by greenhouse effect due to thick atmosphere.g p
When the sky is very clear (without clouds and greenhouse gases) the temperature comesgreenhouse gases), the temperature comes down because of no blanket against infrared
f h fradiation from the surface.
Carbon dioxide makes a greenhouse and if itsCarbon dioxide makes a greenhouse and if its abundance is much lower, the mean temperature of the earth should be lowertemperature of the earth should be lower.
Greenhouse effectSUN
Infrared radiation is absorbed/scattered in the atmosphere.
l d
p
Vi iblVi iblCO2
CO2CloudCloud
VisibleVisibleLightLight
CO2 H2OH2O
Infrared Lightg
Surface
Mars Earth VenusMars Earth Venus
Comparison of the AtmospheresComparison of the Atmospheres
• Venus Thick CO2 Strong Greenhouse– 460 ˚C >> 50˚C (no greenhouse)( g )
– Water unstable
M V thi CO V k G h• Mars Very thin CO2 Very weak Greenhous– ‐ 60˚C
– Water frozen
• Earth N ‐O little CO Moderate• Earth N2‐O2 little CO2 Moderate Greenhouse– 20˚C > 5˚C (no greenhouse)
– Water stable = Ocean
Evolution of the atmosphere:Evolution of the atmosphere:How the Earth decreased CO2 ?
• Carbon dioxide (CO2) was first absorbed by huge sea covering the earthsea covering the earth.
• In the sea, several plants were born and by their photosynthesis effect the plants absorbed carbon dioxide and made oxygen (O2) .ca bo d o de a d ade o yge (O2)
PhotosynthesisPhotosynthesis
Organic mattersOrganic matters
StromatoliteStromatolite
Modern stromatolites in Shark Bay, Western Australia
Stromatolites are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of
i i i ll b t i ( l k blmicroorganisms, especially cyanobacteria (commonly known as blue-green algae). They include some of the most ancient records of life on Earth.
Fossile StromatoliteFossile Stromatolite
Microfossils 3.5x109 yr before present (Australia) that resemble filamentous cyanobacteriacyanobacteria
Increase in oxygenIncrease in oxygen
• In the sea chlorophyta produced oxygen by• In the sea, chlorophyta produced oxygen by photosynthesis and oxygen amount increased to be 1/100 of the present Then multicellular organism1/100 of the present. Then, multicellular organism appeared on the Earth. It was 800 million years ago that crustacean and mollusk appeared when oxygenthat crustacean and mollusk appeared, when oxygen amount was 1/10 of the present. Accordingly ozone (from three oxygen atoms) started increasing and the(from three oxygen atoms) started increasing and the ozone layer in the upper atmosphere stopped solar UV and X ray which are poisonous for the lifeUV and X‐ray, which are poisonous for the life. Formation of the ozone layer promote the life on the landland.
ChlorophytaChlorophyta
multicellular organismmulticellular organism
crustacean mollusk
Global WarmingGlobal Warming
Organic materials containing carbon produced by photosynthesis were stored underground; oil was produced from organic materials. Coral reefs formation in the ocean capture carbon dioxide. (Limestone is composed of fossils of coral.) In recent 300 years as industrial activity has been very active by using oil and coral. Then much carbon dioxide was again produced.
In the recent 50 years or so, global warming has become a serious problem.p
Oil Field
Coral Reef
Global WarmingGlobal Warming
• Increase in carbon dioxide in the atmosphere enhanced the greenhouse effect that delays the escape of energy obtained from solar radiation. That results in the global temperature increase, i.e., global warming.
• Melting of glaciers by the global warming should raise the sea level, which would be fatal for low‐elevation islands.
• Japan is now in “temperature” zone. As proceeds the global warming, Japan will enter “subtropical” g g, p pzone with hotter and more humid climate.
Light pollutionLight pollution
• Astronomical observation is strongly affected by “light pollution”, excessive obtrusive artificial g plights. Especially in and around the large city, artificial lights brighten the night sky andartificial lights brighten the night sky and prevent star observation. Under the sky glow of artificial lights which affect long exposureof artificial lights which affect long‐exposure photographing, it is very difficult to observe dark stars. From the beginning of 20th century, astronomical observatories moved from cities to remote places with dark sky.
Dark sky
Light pollution
• Looking down the night earth from the space, we realize too much light have escaped to the sky. This amount is much greater than the least gnecessary illumination for lands.
• Light Environment Ordinance(Outdoor Lighting Ordinance)
In order to decrease light pollution, Bisei‐town, g p , ,Takayama‐village, Hamamatsu‐city, Tucson‐city (US) enacted “Light Environment Ordinance”. For(US) enacted Light Environment Ordinance . For example, streetlights should be covered not to emit light upward to the sky This would alsoemit light upward to the sky. This would also decrease the power consumption.
Earth at night from a SatelliteEarth at night from a Satellite
Habitable planet (habitable zone)Habitable planet (habitable zone)
Li id t i t bl th f f l tLiquid water is stable on the surface of a planet.
Factors controlling “habitability”Factors controlling habitability
• Distance from the sun (main star).
• Atmosphere (Greenhouse effect).Atmosphere (Greenhouse effect).
• Gravity– Too small planets do not have atmosphere.
• Composition (presence of water).Composition (presence of water).
• Luminosity of the sun (main star).
Mars was habitableMars was habitable.
River delta
Sedimentary rocks
Why was Mars habitable ?Why was Mars habitable ?
• Thick CO2 atmosphere 4.0 billion yr ago.
• (3‐5 atm. PCO2)(3 5 atm. PCO2)
• Strong greenhouse effect.
• Thick atmosphere ‐‐ escaped ?Thick atmosphere escaped ?