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62 Cards in this Set
- Front
- Back
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copernican principle |
- Earth is not special -Mediocrity principle- your going to pick the common thing -Cosmological principle-the laws of physics work all over- same if you step back far enough |
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History of the Earth |
1.Planet forms 2.single celled life 3.multi celled life 4.fish 5.amphibians 9. Homo sapiens 6.reptiles 10. Agriculture 7.dinosaurs 11.Copernicus 8.mammals 12. Today **events closer at end of timeline** |
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Planet forms |
-mid 90s we start finding other planets and systems -Data continues to support our theory -Earth is not unique |
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Chemical Evolution |
-vulcanism- hydrogen, nitrogen and carbon compounds -The Earth cools: ammonia, methane, carbon dioxide and water form -lightning, UV radiation from the Sun, Earth's radioactivity: energy to make more complex molecules |
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bulding blocks of life |
-amino acids- forms proteins --> control metabolism -Nucleotide bases --> form the genes in our DNA |
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Urey Miller Experiment |
-1956 -Zap a warm mixture of water, methane, carbon and ammonia with lightning -week later --> amino acids -biological molecules can be made by a non-biological process |
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Protein like microspheres |
-add heat to amino acids --> something similar to cell -droplets grow and reproduce -NO DNA |
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Life from space |
-Did earth have enough raw materials and energy -zap icy mixture of water, methanol, ammonia and carbon monoxide with UV radiation --> droplets become organize molecules inside |
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Avidence of organic molecules in sapce? |
more complex molecules (organic) are found in interstellar clouds comets have organic material Murchison meteorite has 12 amino acids |
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biological evolution |
3.5 BYA simple one celled creatures 2 BYA complex one celled creatures 1 BYA multi celled creatures etc... |
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where has life been foud |
around deep sea hydrothermal vents 5 foot deep lake under 800 meters of ice sands of the driest desert on earth inside rocks |
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what is life |
reacts to its environment grows by taking in material and processing it it reproduces passing along characteristics to offspring evolve and adapts from generation to generation |
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Horses or Zebras |
The chemicals needed are abundant in space and building blocks are easy to make in the lab |
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Venus life |
-bacteria in earths clouds -50km on Venus's surface pressure and temp similar to earths -life would have to be able to withstand acid and have UV protection -could have developed when venus was like earth and adapted as conditions changed |
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Evidence for life on Venus |
SO2 and H2S react with each other --> something must be producing them -carbonyl sulfide is very hard to produce inorganically -large non-spherical droplets in the clouds, bacteria? |
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When was first planet discovered |
'88-'89 by UBC & Uvic researchers -1970 exoplanets and 490 planetary systems -different detection techniques |
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DIrect iminging |
stars are bright, planets get lost in glare easier to see in infrared light works best for: nearby stars, dim stars, large planets, planets obriting far from their star, hot planets, face on orbits -bad for determining mass or size but GOOD FOR ATMOSPHERES |
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Transits |
-a planet passing in front of a star will dim stars light -works best for: big planets, non-variable stars, nearby or distant stars -1225 planets found this way -GOOD for determining SIZE AND ATMOSPHERE -can only detect edge on systems |
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Kepler |
-continually monitored the brightness of about 150 000 stars -tracking system broke -modified search -over 4000 possibilities and 1/4 confirmed |
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Radial Velocity |
Planets and stars orbit their mutual centre of mass -stars wobble because of their planets' gravitational pull |
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Radial velocity |
-stars wobble because of their planets' gravitational pull -works best for: nearby stars, big planets, close in planets -GOOD for determining LOWER LIMIT OF MASS -No good at face on systems |
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Astrometry |
-Radial velocity is motion towards and away -need accurate measurements on star's positions against the background |
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Light as a wave |
white light is made up of all colours -use something that affects different colours differently to split up light -light is a wave -different colours have different wavelengths -long infrequent waves are different than short -rainbow --> spectrum |
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Spectra |
-look at suns spectrum and certain colours are missing -gasses in the Sun's atmosphere have absorbed those wavelengths -gasses can only absorb or emit wavelengths that match up with their atomic structure |
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Spectroscopy |
-each gas has its own unique fingerprint -split up in the light from something in space -identify the gasses in the thing -line strength width can tell us about temperature, density, magnetic field etc.. |
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How to measure towards and away motion? How to determine an atmospheres composition? |
SPECTROSCOPY |
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Doppler effect |
something making noise coming towards you its higher pitched moving away the sound is lower EX: sirens |
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Waves and frequencies |
-if something giving off waves in coming towards you, the waves hit you more frequently -when its far away they hit you less frequently -humans detect changing sound wave frequencies as changes in pitch |
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Redshift and Blueshift |
-if something giving off light and is coming you the light is bluer (high frequency) -When it's moving away its redder (lower frequency) -look for spectral lines shifter from where they should be |
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Martian meteorites |
-NASA has 52 meteorites that we ejected from Mars at various times -only samples available -some have microscopic |
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challenges for life on Mars |
-radiation and charged particles can damage or destroy living cells -mars currently has no atmosphere or magnetic field for protection -major consideration for sending humans to Mars |
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Mars 2020 |
-NASA mission planned to launch in 2020 -rover with instruments to look signs of past life -will try to make oxygen from the Martian atmosphere |
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Viking landers |
-scooped up martian soil -offered nutrients and radioactively tagged compounds, looked for signs they had been eaten or inhaled -no results |
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ExoMars |
ESA mission planned to launch in 2016 and 2018 -might re-do biological experiments -will map mars' methane |
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Methane on Mars |
-Ground based telescopes saw methane plumes during warmer seasons -curiosity rover measured two 10x methane spikes over 20 months -India's orbiter mission trying to map methane |
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Methanogens |
-methane is unstable -Methanogens on Earth don't need oxygen or sunlight, live on hydrogen and CO2 and produce methane -hydrothermal vents -glacial ice from 3km down -desert sand -your gut |
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Planetary protection |
-spacecraft are sterilized so we don't send our bacteria into space -swabs of the curiosity rover showed 65 species that survived cleaning -in the lab 11% survived mars like conditions |
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Ecopoiesis on Mars |
-the creation of an ecosystem capable of sustaining life -NASA is funding a company to develop a device tat could use extremophile algae and cyanobacteria to produce oxygen |
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Space Law |
-united nations outer space treaty of 1967 forbids harmful communication of other worlds -special regions on Mars are places to be especially careful |
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Jovian Moons- Enceladus |
-fine ice -tidal stresses keep it warm -another ocean beneath its crust -Cassini flew through the geysers -sand and organic molecules warmer then expected |
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Cassini Future Plans |
crashed into saturn to avoid contaminating its moons send a more sensitive detector to do lots of fly throughs |
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Jovian Moons- Europa |
-Hubble space telescope saw light in its aurora -gas being excited was water vapour -possibly geysers -too much radiation from Jupiter to spend lots of time there -map the surface in visible light, heat and chemical composition |
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Jupiter Icy Moon Explorer |
ESA two fly bys first subsurface soundings of Europa |
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Titan- Huygens probe |
-smoggy atmosphere of nitrogen, methane, ethane, propane carbon monoxide -methane rain snow and fog -ethane rivers, lakes and oceans -cold pre-biotic earth with no water vapour |
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Titan life in future |
5-6 billion yrs from now sun will become a red giant --> engulfing the inner solar system -bigger sun --> Titan is close to heat -Less UV radiation --> less haze in atmosphere --? warm up |
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Active SETI / METI |
nearest planet: Alpha Centauri Ba or bb -4.4 ly away Nearest habitable planet: Tau Cetie e? -12 ly away |
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interstellar travel- light yr |
-ly= distance light can travel in one year -9 460 000 000 000 km -fastest space ship - 180 000km/h -6000 yrs to travel 1 ly -48000 yr for round trip to Alpha Centauri |
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Pioneer Plaques |
attached to the pioneer 10 & 11 spacecraft -designed in 3 weeks -12 light hours away -Pioneer 10 will pass within 4y of another star in 10 000 yrs |
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Voyager records |
-attached to the 1977 Voyager 1 and 2 spacecraft -images -Natural sounds -music recordings -recordings from Secretary General of UN and president of USA -farthest is 16 light hours away |
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New horizons |
-has an american flag, state quarters of Maryland and Florida, ashes etc... -we can all upload a message when its finished downloading its data - 10s of thousands of years to the next star |
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broadcasting messages |
light can travel much faster than spaceships radio light has very long wave lengths radio waves are less scattered by dust in space |
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arecibo message |
-sent in 1974 to M13 cluster of stars 25 thousand ly away -because it was there -ones and zeros make a picture |
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lifetime of a technological civilization |
25 000 yrs for the message to get to M13 25 000 yrs for a reply to get back can we last 50 000 yrs |
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Other messages |
-thermin music by russian teenagers beatles song videos from stephen colbert leila lopes 144 character messages from public |
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What would a more advance civilization look like? |
-kepler found a star with 15-20% dips in its light curve -not periodic -normal mature star- no infrared light from debris clouds |
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Radio leakage |
-FM transmitters broadcast parallel to the ground, sending a disk of radio light out into space -Most transmitters are clustered in the Eastern US and western Europe -as they rise and set- alien observer would see regular bursts -our noise is 70ly away |
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Water Hole |
-if we want to look for messages sent on purpose look at 1.5 GHz/20cm frequency/wavelength -our atmosphere doesn't block those waves |
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History of SETI |
-1900 Tesla thought they had picked up signals from mars -1924 mars was closest its ever been -US national radio Scilence day |
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Modern SETI |
1960s-looks for light in the water hole frequencies 1970s-ohio state uni SETI program sees signal 30x stronger than the background noise (never seen again) 1980s-90s- Gov't funding slows down- SETI institute founded |
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SETI Today |
350 six meter dishes to do SETI and radio astronomy SERENDIP- collects data for SETI while other astronomy is happening |
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Breakthrough listen |
100mil form Russian business men help fund radio telescopes in exchange for time on them thousands of hrs per year as much data in one day as pervious projects did in a yr |
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Fermi Paradox |
Sun is typical star high probability some of these stars will have planets similar to earth milky way galaxy could be completely traversed in a million yrs |
