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41 Cards in this Set
- Front
- Back
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What is the fundamental problem to be overcome in finding planets?
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Planets are much dimmer than the stars that they are orbiting. And are very close to the bright stars.
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Be able to identify and describe the five methods for extra solar planet formation
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Direct Imaging - see light from planet
Astrometric - patterns of star position on the sky Doppler - look at periodic shifts in stellar spectral lines Eclipsing - periodic changes in total light from a system Microlensing - nearer planetary systems can focus the light from distant stars |
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Understand the Doppler Effect and its use in planet searches
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The Doppler Effect is the same theory as Red Shift and Blue shift theory. That the gravitational pull of the stars will change in relation to stars
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How does the planet mass affect Doppler shifts?
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The mass effects Doppler shifts because the mass dictates the gravitaitonal force of the central star
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What are the characteristics of detected extrasolar planets?
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There are about 400 ESPs
Range of masses ( 3-10x Earth Mass to 10x Jupiter mass) Description of mass and radii of orbit - high mass with small orbits. This is different from our solar system. How do varying distributions compare to our solar system (it is different.) |
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What might explain these characteristics?
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The new techniques that we have been using are relatively new (ten years) so we can only see small orbital radii so our sample is skewed. Also, they rely mainly on the gravitational effects of the largest planets are easiest to find.
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What are proplyds? What do they have to do with solar system formation?
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Proplyds are disks of material found around young stars and protostars. They are an intermediate step between nebulae and systems.
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What are the main characteristics of life?
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Structure or order
Energy utilization Response to environment Heredity and reproduction Growth and development [Answer will be Obvious] |
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What are the four main chemical ingredients of life? How much of life by mass are they?
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Carbon
Hydrogen Oxygen Nitrogen make up about 96% of life on earth |
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What makes carbon so important?
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carbon is great for forming long chains of molecules that are needed to create the elaborate processes of human life. There are many elements that can achieve this level of complexity but Carbon is very common.
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How does the chemical composition of life compare to other astronomical environments?
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Our chemical composition is most like the universe as a whole.
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What percentage of life is water? What role does water serve?
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70% H2O. Water serves as a transport agent. and a participant in the metabolic process
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What role does DNA play?
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DNA is the foundation for complexity and heredity. It is the map of existence.
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What is a gene? About how many are in human DNA?
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its the indicator for specific traits 23000
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What is the role of a cell in Earth life?
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all life on earth is cellular.
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What is metabolism?
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Energy utilization
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What is a biomarker? What are the oldest on Earth?
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Its like a fossil. It is something that marks historical biology. anything that you can use to tie the biology to the history of the earth. [Chemical isotopic abundances, fossils, etc.] They go back roughly 3 million years
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When could life have emerged on Earth?
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roughly 500 million years after origin of earth. we think this because there are signs of water and this was the end of the heavy bombardment stage.
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What is a Miller-Urey type experiment? What kinds of results are seen?
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M-U experiments are those that try to reproduce the early earth environment and see what hilarious organic chemistry ensues.
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What is the most prominent role of astronomical environment in the most recent fossil record (say last
500 million years)? |
Indirect evidence that collisions could be responsible for mass extinctions.
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What are extremophiles?
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organisms on earth that live in extreme environment. (Not Cheesy Doritos)
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What kinds of physical parameters can be changed to make the environment extreme?
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Temperature
Pressure Ph Water Oxygen Radition |
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What temperature ranges are good for most Earth life? What are the extreme ranges?
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20 - 40 Celsius is good for most Earth life
but it has been from -18c to 115c |
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What is a habitable zone?
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the region around a star which you can reasonably expect to find liquid water. does not guarantee life.
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Is the Sun’s luminosity constant? How has any changes affected the habitable zone?
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the suns luminosity is not constant. The sun has gotten hotter and brighter. the habitable zone will move outward.
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How does the Sun’s energy flow change with distance from the Sun?
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the energy falloff is inversly and exponentionally proportional. One over R Squared. The energy will emanate from the star to from a sphere of energy with its center being the sun. this sphere does not lose energy but most constantly increase its area so its intensity must lower.
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What defines the habitable zone?
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Potential for liquid water
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What factors aside from distance from a central star affect a world’s ability to have liquid water?
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Atmosphere
Internal heat Tidal forces |
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What is the continuous habitable zone?
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Parts of space surronding central star that remains in the Habitable zone despite an increase of star temperature and Habitable zone radii increases that are stlll in the Habitiable zone
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Where are the inner and outer boundaries of the current habitable zone for optimistic and conservative
estimates? What are the only objects safely within the zone? |
Skip -
Oh....its us. just....be able to guess... |
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Be able to describe the change in the habitable zone with time. What causes this?
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It expands due to stellar growth
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What are brown dwarfs? How might such an object host a world with life?
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Brown dwarfs are failed stars. They are balls of gas that are too small to become main sequence stars. They can still provide enough heat to support life due to tidal forces.
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What are the hurdles facing life on Earth as our Sun evolves?
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the sun will get hot and kill us all.
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How does the spectral classification scheme for stars work?
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A grid pattern. using numbers. O 0-9 are hottest...
OBAFGKM from O0 to M9 defined through spectral lines |
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What types of stars are likely to be the best hosts for life? What are the different problems for hotter
versus cooler stars? |
F's G's and K's are the best place to look because of temperature.
O's are short lived because the stellar fusion burns it out too fast for complex life to develop. M's live a long time but do not provide enough energy so the habitable zone is very close. The tidal forces creates a locked rotation of planets. [Half light, half dark] And they have more frequent solar flares which would hit the close planets. |
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Where might habitable zones lie in binary systems?
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Very close to the stars, or very far away. 2/3 of stars are in binary orbits. we find planets very close to one planet to mitigate the gravitational forces of the other star. Can be at the "thirty yard line" or super far away to avoid both.
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What dangers do A and F stars pose in terms of ultraviolet radiation?
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They have lots of it...and thats not good...Sad Mutated Panda
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What stellar classes are most common? Which are brightest? Hottest? Longest lived?
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Cooler means more common because they live longer. Hotter stars (OB) are brighter. Cooler (KM) are longer lived.
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What are some objections to life around K and M stars? How might they be overcome?
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Its cold so there is tidal locking...solar flares
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What is the nature of multiple star systems? About how many stars are in such systems?
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Systems with Multiple stars. about 2/3 of all stars are in MSS
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What challenges to binary systems create for stable orbits?
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There is another huge gravitational force affecting the orbiting planet.
Gravitational Mayhem |
