Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Astrobiology > Astrobiology Test 3 > Flashcards

Astrobiology Test 3 Flashcards

1
Q

Describe Mercury

A 
Smallest planet
Very hot during the day, very cold at night
Virtually no tilt
Possibility very transient liquid water
Metallic core with outer shell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe Venus

A

Hottest - greenhouse gases (H2O vapor and CO2)
Sulfuric acid clouds, chloride, iron, sulfur
Spins “backwards”
Iron core, thin surface, active volcanoes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe Earth

A

Evidence of life in radio waves, oxygen and methane in spectral data
Moon formed by impact by Mars-size object, produces tides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe Mars

A 
Thin atmosphere
Frozen surface water
Subsurface briny liquid water
No magnetic field
Iron regolith
Lava tunnels
Similar composition to Earth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe Ceres

A

Asteroid belt
Water ice - maybe more than on Earth
Salts of magnesium sulfate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe Jupiter’s moons

A

Io - most volcanically active
Europa - Subsurface ocean, cracks indicate tidal fluxing or other energy input such as volcanic eruptions / deep sea thermal vents, iron core
Ice covered lake in Antarctica studied as analog
Ganymede - iron core, rocky mantle, layer of ice

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe Saturn’s moons

A

Enceladus - icy, possibly liquid water / carbon dioxide / methane in jets
Titan - too cold (liquid ethane and methane), nitrogen atmosphere, pressure 50% higher than Earth, subsurface water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe the benefit of Moons and atmospheres

A

Moons and atmospheres help to stabilize the environment, atmospheres protect from UV radiation and solar radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are three general things determining the plausibility of life?

A

Liquid solvent, energy, ability to form large, complex molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Assumptions for life to begin and continue (2)

A

Stable environment

Reactions for life formation occurring rapidly (geologically)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Category Two Planetary bodies

A

Past or present liquid water, energy, organic compounds, stable history
Mars, Europa, Enceladus
-could have life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Category Three Planetary bodies

A

Physically extreme conditions, energy, complex chemistry
Titan, Venus
-could have life as we don’t know it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Category Four Planetary bodies

A

Past isolated favorable conditions
Triton, Io, Mercury
-may have very isolated life due to past conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Category Five Planetary Bodies

A

All conditions are unfavorable for Life

Saturn, Jupiter, Moon, Sun

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Category One Planetary Bodies

A

Liquid water, energy, organic compounds, atmosphere, biogenic processes
Earth
-do have life

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Giordano Bruno

A

Proposed the existence of exoplanets in the 17th century

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Adriaan van Maanen, 1917

A

Described a “Polluted White Dwarf”, and the image was later found to have first evidence of an exoplanetary system surrounding it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

White Dwarf

A

White dwarfs are the remnants of stars like ours that have become very small, compressed, and hot, usually characterized by hydrogen, helium and oxygen
The Van Maanen dwarf also had calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

1990 reexamination of the “polluted white dwarf”

A

Re-examined glass plates of the polluted white dwarf
Found calcium along with other elements associated with rocky planets in a disk around the dwarf

Indicated a planetary body like Jupiter pushing asteroids, comets, and other rocky bodies towards the gravitational pull of the white dwarf but also preventing them from being entirely consumed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Detecting light from planets

A

Planets only reflect a small amount of their sun’s light and don’t emit any of their own

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Methods of detecting planets

A

Transit, Radial Velocity, Microlensing, Astrometry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Transit method of detection

A

small dip in light when a planet passes in front of its sun
Size and temperature of planet, maybe atmospheric composition
Discovery of most exoplanets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Radial velocity method of detection

A

gravity causes star to wobble, shift spectral lines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Microlensing method of detection

A

planet warps space, creating a gravitational lens magnifying light
two stars aligned with observer, closer star acts like a lens to bend light, exoplanet around closer star results in a spike in brightness levels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Astrometry method of detection
Measures the location of the star and those around it for tiny changes, then use gravitational microlensing
26
Kepler Telescope
Specifically designed to discover exoplanets using the transit method - Confirmed 200
27
Spitzer Space Telescope
Decommissioned in 2020 Studied infrared spectra - "the old, the cold, the dusty" Found 7 exoplanets around TRAPPIST-1 40 light years away -1999
28
Transiting Exoplanet Survey Satellite
TESS - confirmed 122 exoplanets over 3 years, with 2601 candidates
29
Nancy Grace Roman Space Telescope
Used both transit and gravitational lensing method
30
Classification of exoplanets - Gas giants
Jupiter-like or larger
31
Classification of exoplanets - Neptunian
small gas giants, around the size of Neptune
32
Classification of exoplanets - Super-earth
rocky planets much larger than Earth
33
Classification of exoplanets - terrestrial
rocky planets around the size of Earth
34
Camile Flammarion
Wrote The Planet Mars
35
Schiaparelli
found straight lines called channels connecting "oceans" on Mars
36
Cassini
seasonal changes on Mars
37
Proctor
Named geographical features after scientists
38
Confirmed vs candidate exoplanets
Candidate - signals seen by one telescope | Confirmed - two lines of evidence
39
Naming exoplanets
Name of the telescope Number relating to the order in which its star was catalogued Lowercase letter indicates planet order Ex: Kepler-16b was discovered by the Kepler telescope, in the 16th system discovered by Kepler, and is the closest planet to the star(s) Capital A for star name, Capital B for second star
40
How many potential planets in Milky Way
100 billion
41
Types of Stars (3) and Goldilocks zone
G-type → yellow, 6%, hottest, last around 10 billion years, largest Goldilocks zone K-dwarfs → orange, 13%, last from 15-45 billion years, 5-25x X-ray radiation Highest likelihood of exoplanets with life M-dwarfs → red, 73%, last over 100 billion years, 80-500x X-ray radiation, smallest Goldilocks zone
42
How many confirmed exoplanets? Terrestrial type planets?
4375 | Terrestrial type planets are in the minority
43
Requirements for life
Bounded local environment with disequilibrium (cell-like structures) Consume energy to maintain internal order and adjust to the environment Replicate by passing on hereditary information from one generation to the next
44
Life based on spin configurations
``` Gerald Fienberg and Robert Shapiro Orientations of hydrogen atoms Cold environments with solid hydrogen Infrared as a source of energy Issues with bounded local environment ```
45
Fred Hoyle's Black Cloud
Hoyle worked in nucleosynthesis of heavy elements in stars, named Big Bang theory Thought the universe was static Book about a dark object blocking out the light from other stars and expanding into our solar system blocking out our sun Object would communicate using radio waves Issues with replication with hereditary information
46
Quantum computers
Store information on molecules that change conformation in response to light Use qubits that can take on more than two forms More possible states involve more potential mistakes Requires extreme stability (cold)
47
Neutron star
Formed from a collapse of a massive star after a supernova explosion Possesses masses between 10-25 solar masses Smallest and densest other than black holes Electrons and positrons cancel out and become neutrons Magnetic energy makes life on surrounding planets very unlikely Detected by infrared telescopes
48
Types of neutron stars
Pulsars - Energy and light emitted from magnetic poles, stars are rotating very fast Magnetars - trillion times the magnetic field of Earth, 1000x that of regular neutron stars, release burst of magnetic energy
49
Brown dwarfs
In between gas giants and stars Described by Jill Tarter First evidence in 1995 15-80x mass of Jupiter Insufficient material to start fusion reactions (some can fuse deuterium) Orbit other stars around 1000AUs away or are rogue Discovered by Spitzer / infrared telescopes
50
Types of brown dwarfs
L brown dwarfs → 1200-2000*C | T brown dwarfs → < 1200*C
51
Habitability brown dwarfs
No life due to high temperatures and lack of a surface, lack of heavier elements, severe weather May have their own planets circling them Very narrow habitable / Goldilocks zone Forms of energy - magnetic?, light and photosynthetic organisms, Lack of stable environment
52
Rogue planets
Billions of trillions in Milky Way, planets without a host star
53
Formation of Rogue Planets
``` Collusions while system is forming Gravitational pull or lack thereof Formation of lone brown dwarfs As stars age, can have decrease in gravitational pull Ricochet from multi-star system ```
54
Characteristics of Rogue Planets
Most are gas giants, some are rocky planets | Can be detected by microlensing → light from star becomes aura as planet bends space when passing near it
55
Life on Rogue Planets (energy, water, metabolism)
Sources of energy → geothermal through plate tectonics or radioactive elements, retention of infrared energy through thick atmosphere with N2/CO2/CH4/C2H6 Water → Accretion during formation, outgassing during accretion (certain reactions between early materials during formation) Life → if so, microbial with chemolithotrophic metabolism
56
Evolutionary fates of life
Species collapse Transition Plateaus
57
Species collapse
Non-reversible adaptations followed by rapid environmental change and a lack of suitable adaptations Past evolutionary success no longer providing adaptations (slow environmental change) Well-adapted organisms displaced by better adapted species (invasive species or other competition)
58
Species transition
Becoming different species Punctuated equilibrium model of origin of species Major transitions on Earth → eukaryotic organisms, photosynthesis (oxygenic esp), calcified exoskeletons, aquatic to land, invertebrates to vertebrates, multicellular life, sexual reproduction
59
Species plateaus
Stable environment | Bacteria, archaea, some multicellular life
60
Characteristics of Intelligence
``` Ability to communicate Utilization of tools, development of technology Remembrance Coordinated activities Mourning / Emotions ```
61
Rise and fate of technology
Technology → use of energy, tools, materials, and information to amplify the impact of a species on its environment Fates of population with advanced technologies: Custom-designed, genetically engineered organic beings Totally mechanical forms with artificial intelligence Virtual (non-material) entities Destroy itself
62
SETI
Search for Extraterrestrial Intelligence SETI was started by NASA, switched to private donations in 1993
63
Philip Morrison and Giuseppe Concori
can receive radio signals from light years away
64
False Positives in SETI
pulsars, terrestrial origin, rotating neutron stars (ideally would have 3 confirmations)
65
WOW signal
Neither very regular nor very random signals are indications of possible life Big Ear Telescope in Delaware, Ohio 72 seconds and not detected again Sagittarius part of Milky Way Too short to be get confirmation by other telescopes
66
SETA
Search for Extraterrestrial Artifacts (SETA) | Space structures - dyson sphere
67
Drake equation
Number of possible civilizations that could make contact N = R* times FP times NE times FL times FI times FC times L Rate of star formation, fraction of stars with planets, number of planets capable of supporting life, fraction that do sustain life, fraction with intelligent life, fraction with communication, length of time for signals We would be able to get good guesses with the first three, and estimate the rest L involves the development of the alien society beyond signals we can detect as well as the length of time it takes them to send whatever signal (stars, planets, possible life + life, intelligent, communicate, signals)
68
Fermi's Paradox / Great Silence
Lots of stars → lots of exoplanets → no evidence for life? Reasons → right form of life is very uncommon / we are not looking hard enough, space is big
69
Robots vs Humans space exploration
Humans need radiation protection / food / oxygen, some observations are better in person, can guide rovers on Mars themselves, long transit times Robots have their own instruments
70
Rovers vs Orbitals space exploration
Orbitals have a global view | Rovers have better detail
71
InSight Lander Mission
Lander with two small orbiters Orbiters allow better communication between lander and Earth Focus on geology and interior of Mars, weather on Mars Measure seismology, 480 Marsquakes Geological activity due to past volcanic activity
72
Perseverance and Ingenuity Missions
Astrobiology and previous evidence for life Sample caching Preparing for the arrival of humans Radioactive plutonium Weather conditions X-ray fluorescence spectrometer to determine minerals Ground-penetrating radar that can see subsurface water UV laser for mineralogy and organic compounds MOXIE demonstrates the feasibility of producing oxygen
73
Ingenuity
Helicopter associated with a rover | Helicopter helps determine where the rover should travel next
74
Humans to Mars logistics
Oxygen - MOXIE Nutrients - essential elements Water - frozen/ice on Mars, use Antarctica analogs Shelter - temperature, weather, space suits, UV radiation / space radiation / ionizing radiation (damage to DNA, cells), lava tubes?
75
Moon travel 2024
Ejecta from early Earth impacts preserved in the lunar surface Preserve conditions in early Earth Similar requirements for humans as Mars, expect for the lack of CO2 and the ice limited to the South pole Use as a stopover for Mars missions
76
International Space Station height
250 miles (250,000 to moon)
77
Five Categories of target bodies (with respect to planetary protection concerns)
Category One - no worries about life Category Two - process of chemical evolution and the origin of life, worry about false positives Category Three - flyby or orbiter mission (possible life) Category Four - probe, lander, rover (possible life) IVa - does not have proper instruments IVb - intended to investigate extant life IVc - Martian Special Regions, extant life and possibility for replication of terrestrial life Category Five - something returns to Earth
78
Terraforming Mars
``` Factors Oxygen/Atmosphere - retain heat, dense enough, greenhouse gases May not be enough resources there Liquid water Asteroids Soil/Plants Soil is not super renewable ```
79
Notes from Gravity Assist
Heat shock swab samples so they only look at the stuff that would survive launch 500,000 spores or <300 per square meter Hydrogen peroxide, 70% isopropyl alcohol Missions on the Moon will help plan to prevent contamination on Mars Pulses of elevated methane that disappear (not explained by abiotic)
80
James Webb Telescope
infrared to study the beginning of the universe and the atmospheres of exoplanets using star magnification and transits

Astrobiology (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions