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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
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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

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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

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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
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5
Q

Describe Ceres

A

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

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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

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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

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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

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9
Q

What are three general things determining the plausibility of life?

A

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

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10
Q

Assumptions for life to begin and continue (2)

A

Stable environment

Reactions for life formation occurring rapidly (geologically)

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11
Q

Category Two Planetary bodies

A

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

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12
Q

Category Three Planetary bodies

A

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

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13
Q

Category Four Planetary bodies

A

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

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14
Q

Category Five Planetary Bodies

A

All conditions are unfavorable for Life

Saturn, Jupiter, Moon, Sun

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15
Q

Category One Planetary Bodies

A

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

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16
Q

Giordano Bruno

A

Proposed the existence of exoplanets in the 17th century

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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

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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

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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

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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

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21
Q

Methods of detecting planets

A

Transit, Radial Velocity, Microlensing, Astrometry

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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

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23
Q

Radial velocity method of detection

A

gravity causes star to wobble, shift spectral lines

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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

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25
Q

Astrometry method of detection

A

Measures the location of the star and those around it for tiny changes, then use gravitational microlensing

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26
Q

Kepler Telescope

A

Specifically designed to discover exoplanets using the transit method - Confirmed 200

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27
Q

Spitzer Space Telescope

A

Decommissioned in 2020
Studied infrared spectra - “the old, the cold, the dusty”

Found 7 exoplanets around TRAPPIST-1 40 light years away -1999

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28
Q

Transiting Exoplanet Survey Satellite

A

TESS - confirmed 122 exoplanets over 3 years, with 2601 candidates

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29
Q

Nancy Grace Roman Space Telescope

A

Used both transit and gravitational lensing method

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30
Q

Classification of exoplanets - Gas giants

A

Jupiter-like or larger

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31
Q

Classification of exoplanets - Neptunian

A

small gas giants, around the size of Neptune

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32
Q

Classification of exoplanets - Super-earth

A

rocky planets much larger than Earth

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33
Q

Classification of exoplanets - terrestrial

A

rocky planets around the size of Earth

34
Q

Camile Flammarion

A

Wrote The Planet Mars

35
Q

Schiaparelli

A

found straight lines called channels connecting “oceans” on Mars

36
Q

Cassini

A

seasonal changes on Mars

37
Q

Proctor

A

Named geographical features after scientists

38
Q

Confirmed vs candidate exoplanets

A

Candidate - signals seen by one telescope

Confirmed - two lines of evidence

39
Q

Naming exoplanets

A

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
Q

How many potential planets in Milky Way

A

100 billion

41
Q

Types of Stars (3) and Goldilocks zone

A

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
Q

How many confirmed exoplanets? Terrestrial type planets?

A

4375

Terrestrial type planets are in the minority

43
Q

Requirements for life

A

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
Q

Life based on spin configurations

A 
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
Q

Fred Hoyle’s Black Cloud

A

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
Q

Quantum computers

A

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
Q

Neutron star

A

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
Q

Types of neutron stars

A

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
Q

Brown dwarfs

A

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
Q

Types of brown dwarfs

A

L brown dwarfs → 1200-2000*C

T brown dwarfs → < 1200*C

51
Q

Habitability brown dwarfs

A

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
Q

Rogue planets

A

Billions of trillions in Milky Way, planets without a host star

53
Q

Formation of Rogue Planets

A 
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
Q

Characteristics of Rogue Planets

A

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
Q

Life on Rogue Planets (energy, water, metabolism)

A

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
Q

Evolutionary fates of life

A

Species collapse

Transition

Plateaus

57
Q

Species collapse

A

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
Q

Species transition

A

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
Q

Species plateaus

A

Stable environment

Bacteria, archaea, some multicellular life

60
Q

Characteristics of Intelligence

A 
Ability to communicate
Utilization of tools, development of technology 
Remembrance
Coordinated activities
Mourning / Emotions
61
Q

Rise and fate of technology

A

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
Q

SETI

A

Search for Extraterrestrial Intelligence

SETI was started by NASA, switched to private donations in 1993

63
Q

Philip Morrison and Giuseppe Concori

A

can receive radio signals from light years away

64
Q

False Positives in SETI

A

pulsars, terrestrial origin, rotating neutron stars (ideally would have 3 confirmations)

65
Q

WOW signal

A

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
Q

SETA

A

Search for Extraterrestrial Artifacts (SETA)

Space structures - dyson sphere

67
Q

Drake equation

A

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
Q

Fermi’s Paradox / Great Silence

A

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
Q

Robots vs Humans space exploration

A

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
Q

Rovers vs Orbitals space exploration

A

Orbitals have a global view

Rovers have better detail

71
Q

InSight Lander Mission

A

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
Q

Perseverance and Ingenuity Missions

A

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
Q

Ingenuity

A

Helicopter associated with a rover

Helicopter helps determine where the rover should travel next

74
Q

Humans to Mars logistics

A

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
Q

Moon travel 2024

A

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
Q

International Space Station height

A

250 miles (250,000 to moon)

77
Q

Five Categories of target bodies (with respect to planetary protection concerns)

A

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
Q

Terraforming Mars

A 
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
Q

Notes from Gravity Assist

A

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
Q

James Webb Telescope

A

infrared to study the beginning of the universe and the atmospheres of exoplanets using star magnification and transits

Astrobiology (5 decks)

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