ES1086 EXAM BOLDED WORDS Flashcards
1
Q
Betyls
A
Hebrew for home of God, ancient Greeks and Romans called meteorites betyls
2
Q
Meteorites
A
Highly valued by ancient Egyptians - the rocks have been found entombed with Egyptian pharaohs. The East African Wanika Tribe worshipped a piece of meteorite, but as the enemies burned their village, they concluded that the rock was not good after all & sold it to missionaries.
3
Q
Kaaba Stone
A
Kaaba Stone to which Muslims pay homage in Mecca is a large meteorite - but it’s strictly out of bounds for critical examination! It could just as well be an obsidian (dark volcanic glass) or an impactite (impact glass).
4
Q
Father of Meteoritics
A
Ernst Chladni, published a book of all the data he could find about meteorites in 1774. He was heavily ridiculed and mocked at the time
5
Q
Ceres
A
Asteroid now classified as a dwarf planet
one of the 1st discovered in the asteroid belt by monk Giuseppe Piazzi
6
Q
Asteroid Belt
A
region of space between orbits of Mars and Jupiter where many asteroids can be found.
7
Q
Theories regarding Asteroid Belt
A
Wrong theory: Objects in belt are material left over from planet that was blasted into bits by a collision with a comet
Correct theory: The objects are materials that never assembled into a planet at all, caused by the enormous force of Jupiter
8
Q
Asteroid
A
Natural rocky object in space measuring 100m to several hundred km in diameter
9
Q
Meteoroid
A
Natural rocky object in space measuring from a few mm to 100m in diameter
10
Q
Meteor
A
a visible streak of light from a small meteoroid passing through Earths Atmosphere;
light is the result of friction between object and gas in the atmosphere
11
Q
Fireball
A
light from a large meteoric or asteroid as it interacts with the atmosphere
Very bright compared to meteors
12
Q
Meteorite
A
Fragment (any size) of either a meteoroid or asteroid that lands on Earth’s surface.
It’s not called a meteorite until it lands on Earth’s surface
13
Q
Titius-Bode Law
A
A law predicting the space between planets in the solar system.
14
Q
David Gregory
A
made mathematical sequence which estimates spacing between planets
15
Q
Main Asteroid Belt
A
Majority of the asteroids can be found here between Mars and Jupiter.
Most asteroids here have accurately known circular orbits, and are fairly spaced out from each other appearing mostly empty.
16
Q
Potentially Hazardous Asteroids
A
Asteroids not in the main belt, may cause a threat to us
17
Q
Lincoln Near Earth Asteroid Research (LINEAR)
A
Telescope that is a new asteroid detective which is a highly sophisticated and sensitive electro-optical detector with something called a CCD (charge coupled device) - an array of light sensitive elements that can record very faint images.
As of 2011, LINEAR has found over 231,000 new objects, 2423 of these being near Earth asteroids and 279 comets
18
Q
Asteroid naming
A
assigned a sequential number when its discovered
1 Ceres, 2 Pallas, 452 Hamilton, 1026 Ingrid, and so on
19
Q
15025 Uwontario
A
An outer main-belt asteroid was discovered on October 15th, 1998, and named after Western University
20
Q
Jupiter’s Effect
A
Jupiter has a large mass and high gravitational pull, causing neighboring asteroids to be affected by its gravitation.
Causing the number of asteroids today between Jupiter and Mars AKA main asteroid belt
21
Q
Kirkwood Gaps
A
Explained by Daniel Kirkwood. It is gaps in the asteroid belt where no asteroids exist. That’s because they will get swung out by the gravity of Jupiter which heads towards the inner solar system
22
Q
Albedo
A
proportion of light reflected from an object; 0=pitch black, 1=perfect reflection
23
Q
Spectrometers
A
break down the reflected light in a whole spectrum to tell us which minerals reflect the light
24
Q
Differentiated
A
Asteroids that have been heated by radioactive decay caused by accretion to the extent where it’s interior melts
As they melt, metal can sink toward the center and volcanic rocks (such as basalt) can erupt at the surface.
If these differentiated asteroids are broken apart, layers of different rock types may be exposed. If just the outer layers are broken apart we may see a variety of rock types exposed in a large asteroid. On the other hand, if all of the outer rocky layers are stripped away we can be left with just the metallic core
25
C-Type asteroids
high carbon content or carbonaceous, 75% of known asteroids; roughly similar composition to the Sun, minus volatile elements
2/3 show evidence of water in their mineral structures, which shows up as an absorption feature in the ultraviolet part of the spectrum.
These asteroids range from the middle to the outer edge of the belt.
26
S-Type asteroids
high silicon or silicaceous, 17% of known asteroids
S-type asteroids are confined to the inner belt, but there is some confusion about the S-type asteroids; they do not closely match the spectra of ordinary chondrites.
27
M-Type asteroids
metallic, most of the remaining asteroids
28
Carbonaceous asteroids
Most are high in dark carbon-rich minerals with low albedos
29
4 Vesta
One of the largest objects in the asteroid belt, it is also the brightest in the sky and at times is visible to the naked eye.
Has a metal-rich core half the diameter of its mass.
5.3hr rotation
Struck several times evident by the impact marks
30
E-type asteroids
Asteroids with the highest albedo (40%) are called E-type asteroids
E standing for mineral enstatite
31
Dawn Spacecraft
NASA spacecraft was captured to Vesta’s orbit in 2011 and made the discovery about its metalcore. Also discovered that the biggest mountain on Vesta is larger than Earth.
In 2015, Dawn moved to explore Ceres and captured high reflective spots within craters on its surface.
32
Hirayama families
Astronomer Hirayama grouped the breakup of an asteroid into a collection of fragments which he called a FAMILY.
Families have similar orbital characteristics and members of one family were collision fragments of the same original planetesimal.
In total there are 19 Hirayama families.
33
Near Earth Asteroids/Objects (NEAs)
asteroids and comets that approach or cross Earth's orbit
34
Atens asteroids
Asteroids orbits less than 1 AU, meaning that most of the time they are within the orbit of Earth, though they may cross Earth’s orbit when they’re at their farthest from the Sun
35
Apollos asteroids
Most have orbits that bring them through Earth’s orbit (orbits cross Earth’s orbit).
Earth is hit by an Apollo object once every 250000 years on average. Craters can be 2km deep and 20km in diameter.
36
Amors asteroids
Commonly cross orbit of Mars; they get teasingly close to orbit of Earth but don’t cross
37
Trojan asteroids
group of non-belt asteroids that travel and are trapped in front and behind Jupiters orbit in its Lagrangian points.
38
Torino Scale
Impact potential scale used to determine level of concern of an object colliding with Earth (0 - 10). 8,9,10 = certain collision, life at stake
39
Apophis
previously listed as a 4(highest rating ever awarded) but re-listed as a 0
If it did impact Earth, the energy released would be equivalent to 114000 times the Hiroshima bomb.
40
Meteoritics
Study of meteorites; drawing upon fields such as cosmochemistry, planetology, and space exploration to figure out what meteorites can tell us about how solar system formed, and how planets and asteroids formed.
41
Find meteorite
discovered without prior knowledge of when, where, and how it came to Earth
42
Fall meteorite
witnessed and after seeing its entry through the atmosphere someone has collected a piece/all of that rock
43
Irons meteorites
almost made up entirely of iron + nickel metal alloys.
Makes up 6%
44
Stony-iron meteorites
rare meteorites (1%) have a 50-50 mixture of silicates (stones) and iron-nickel alloys
45
Stone meteorites
most common (93%) made up mostly of silicate stones
46
Chondrites
Stony meteorite that has never been altered or melted.
Chondrites derive from the Greek word chondros which means grain or seed, referring to the small rounded inclusions in Chondrites called Chondrules.
how they formulated: condensed from a hot cloud of gas and dust, very early in the Solar System history, by flash melting of dust aggregates in the solar nebula.
47
Achondrites
stony meteorite; igneous rock that has been at least partially melted or recrystallized.
A fragment of another planet that falls on earth and is the product of crystallization from magma is called achondrites.
48
Pallasite stony iron
metallic looking meteorite with brown/rusted holes
49
Accretion
process of clumping together of the various products appearing in chondrites
50
Igneous rock
magma (molten rock) is formed by melting pre-existing rock at very high temperatures; when that molten rock crystallizes to a solid
51
Residual rock
material left behind that didn’t melt from molten pre-existing rock
52
Primitive achondrite
if the fragment is from residual rock - material left behind that did not melt; it is called primitive achondrite
53
Interplanetary dust particles
micro-sized particles/micrometeoroids orbiting around the Sun are the solar system's smallest meteoroids. These meteoroids are being wiped out constantly by the Sun's flares. They have ability to replace themselves because:
1: asteroid belt send objects/small pieces there constantly
2: dusty trails from comets
54
Pegasus and IRAS.
Two spacecraft sent to detect amounts and locations of dust that would contribute to micro-meteors. They confirmed that the asteroid belt is indeed a major source of micrometeorites.
55
Fireballs
produced by large chunks of rock and iron that were knocked off asteroid parent bodies by collisions.
Particles in an average meteor shower never survive to reach Earth's surface, but most meteoroids that produce fireballs are massive enough to survive the atmospheric passage, often explosively disintegrating into several smaller pieces en-route.
light is normally visible, and sound is commonly heard over 50km
56
Ablation
erosion process by removing small masses during atmospheric drag
57
Inertia
Tendency for an object to resist change in its motion
58
Momentum
Product of an object’s mass, volume, and velocity. The more mass the meteorite is, the faster it travels, and the greater the force needed to change its direction
59
Kinetic energy
Energy gained by a meteorite according to its motion. The heavier and faster a meteorite is moving, the greater its kinetic energy, the greater atmospheric resistance.
60
Regmaglypts
Meteorite surfaces marked with depressions resembling thumbprints from ablation
61
Fusion crust
The crust of a meteorite caused by its entry into Earth's atmosphere.
a layer (usually less than 1 mm thick) of glass (commonly dark or even black in color)
62
Meteorite hunt
Antarctica is the best place to look for meteorite because of its open grounds and cold condition to preserve it. The meteorite found belongs to the landowner it fell on. Otherwise, finders keepers.
63
Petrographic microscope
A specialized version of a binocular microscope
sends transmitted polarized light designed for the study of thin sections of rock or pottery.
64
Electron microscope
microscope that forms an image by focusing beams of electrons onto a specimen.
chemically analyzes the minerals of the meteorites.
65
Mass spectrometer
An instrument that measures the amount of very selective radioactive isotopes in the sample. To understand the age of meteorites.
66
Great Red Spot
a 300-year-old high pressure raging storm on Jupiter
- hurricane-force winds twice the size of Earth
- lightning bolts, and swirling vortex of clouds
67
Io
Innermost moon/satellite of Jupiter orbiting every 2 days
most volcanic active body in the solar system
- The closest satellite to Jupiter- which is also the densest.
- Has a partially molten core of iron and sulfur
- There are over 150 active volcanoes on Io's surface - which cause no crater impacts at all - the lava that is blasted out constantly buries any craters that can be formed.
- Io is heated by tidal heating which affected Ganymede and Europa
68
Ganymede
Satellite of Jupiter
-seems to have a water 'slush' ocean beneath a solid ice cover
- The 3rd outermost Galilean Satellite.
- The largest out of the 4, larger than the moon & mercury.
- Molten iron-rich core, with liquid salty ocean
- One of the only satellites that have a magnetic field - due to its molten core which is very hot to generate heat.
- Has its own extremely thin atmosphere, primarily oxygen and hydrogen (no nitrogen unlike Earth)
69
Callisto
Satellite of Jupiter
-a body that never chemically differentiated
- The outermost of the four satellites
- A mixture of rock & ice
- Has a very weak magnetic field - no dense core / its interior is a mix of rock and ice.
70
Europa
A satellite Jupiter
-significant liquid water beneath the surface
- The 2nd inward satellite
- The more inward the satellite, the denser it is.
- Made up of rock and metal
- Surface has ice, almost free of craters
- Does not have a molten core
- Heat is a result of tidal heating, because of the cracks of its ice surface clearly showing convection beneath.
71
Galilean satellites
Jupiters four main satellites
| -named this in honor of the first man to describe them Galileo
72
Pioneer 10
- spacecraft to photograph Jupiter
- over 500 images
- fictional pioneer 10 was used in Star Trek V: the final frontier
- it has left the solar system
73
Pioneer 11
- better pics than pioneer 10
- measured Jupiter's intense charged particle and magnetic field environment
- it has also left the solar system
74
Voyager 1 and 2
-Voyager 1 made the closest approach on March 5,1979 to Jupiter
- Voyager 2 followed in July
- images showed complicated swirling turbulence of Jupiter's atmosphere
- Voyager 1: discovered 9 active volcanoes erupting on io
- Voyager 2 found that 8/9 were still erupting 8 months later
- Rings were also discovered
75
Galileo Spacecraft
- First spacecraft to orbit Jupiter
- Studied Jupiter's atmosphere, satellites
- Found that there's saltwater in Europa.
- Sent crashing to the surface of Jupiter to not contaminate Europa
- It changed the way we think about the Solar System
76
New Horizons
Passed Pluto in 2015 and is heading for the Kuiper belt
Passed the Jupiter system in 2007
Took great images
77
Juno
The first solar powered spacecraft with the goal to study early history of Solar System- since Jupiter was the first to form.
78
Obliquity
axial tilt
-the angle between an object rotational axis and its orbital axis or equivalently the angle between its equatorial plane and orbital plane
-Jupiter has a v upright stance w a mere 3* of obliquity
--> has a fast rotational period (9hrs 55 mins) as Jupiter orbits the sun
79
Oblateness
Bulges slightly at the equator
-Jupiter is mostly liquid, not having a hard surface, it rotates fast having detectable oblateness
80
Jupiter's Interior heat engine
- Jupiter emits about 1.7x as much energy as it receives from the sun
- Jupiter's weird interior is responsible for this
- from true gaseous hydrogen rich atmosphere it turns to a liquid hydrogen then to 'metallic' hydrogen and finally a heavy metal core
81
Speculation about life in the oceans of which satellites
Europa
Ganymede
-for life to exist radiation strength would have to be decreased substantially by the time it reaches them
82
Atmosphere structure Instrument (ASI)
- carried by the Galileo probe
- sent the ASI into the atmosphere of Jupiter
- made most difficult planetary atmospheric entry ever attempted
- detected high winds and v intense turbulence during descent through the thick atmosphere
- confirmed theories that the source driving much of Jupiters distinct circulation phenomena is probably heat escaping from the deep interior
83
Dark belts and bright zones
- clouds of Jupiter are organized into dark belts and bright zones
- belts: appear to be regions of descending gas
- zones: appear to be high-pressure regions of rising gas that cools as it rises and forms clouds higher in the atmosphere, where they receive more sunlight and look brighter
- belts are low-pressure regions w sinking gas and lower clouds that are not as brightly lit
84
Galilean Moons (AKA satellites)
- 4 largest satellites of Jupiter
- seen through a crude telescope
- all are tidally locked to Jupiter, meaning that they keep the same face facing Jupiter forever
85
Regular satellites
- define the outer orbital reaches of a planets domain in space
- ex. Io, Europa, Ganymede, Callisto
- are large and round
- tend to have stable, simple, nearly circular orbits
- all move through a plan in space that is roughly equal to the planets equatorial plane
86
Formation of regular satellites
2 hypothesis:
1. they formed out of the same nebula of gas and dust that built the planet and likely at the same time THIS IS WHAT EVERYONE BELIEVES
2. they formed by collision. our moon is an ex of this
87
Irregular satellites
- these are of unknown origin
- almost certainly captured objects
- typically small
- all look to have similar composition and trajectories
- great amount of objects in one segment of the Kuiper belt
88
Trojan Satellites
- Satellites that orbit the sun, but is also gravitationally bound to their planet at the same time
- Lagrangian points (60* ahead&behond Jupiter)on its sun's orbital path, 2 packs of asteroids here. Do not orbit Jupiter
- Earth only has one true Trojan called 2010 TH7 sharing Earth's orbit
Earth has acquired a sort of enhanced Trojan, a rock called 2002 AA29
89
3 important principles in comparative planetology
- composition depends on the temp of the material from which it is formed. ex: ice in the outer solar system where sun is weak
- cratering can tell the age of a hard surface
- internal heat has a powerful influence over the geology of these larger satellites
90
Ganymede (points in bold)
- interior estimated at 1500K-1700K
| - very thin atmosphere (about 1/10,000 the pressure of earths atmosphere)
91
Tidal heating
- important for Europa and apparently provides enough heat to keep the little satellite active, obviously active because the ice surface is covered w cracks, showing the effect of convection beneath
- Tidal heating occurs through the tidal friction processes: orbital energy dissipated as heat in the surface ocean or interior of a planet or satellite.
92
Active volcanoes
over 150 present on Io
- Io is the most volcanically active body in the solar system
- volcanism is virtually non-stop
93
Orbital resonance
A situation in which one object's orbital period is a simple ratio of another object's period
- Io, Europa, and Ganymede are locked in an orbital resonance: in the time it takes Ganymede to orbit once, Europa orbits twice and Io four times. This gravitational interaction keeps the orbits slightly elliptical, and Io, being closest to Jupiter, suffers dramatic tides, with its surface rising and falling by about 100 m!
- result is enough friction too melt the interior and drive volcanism
94
Saturn mission: Pioneer 11
- 79' flew within 20,000km of the planets cloud tops
- took pics of rings
- took temp of titan (largest satellites)
95
Saturn mission: Voyager 1&2
- provided data for the Cassini-Huygens mission
- hydrogen/helium ratio of the atmosphere
- winds and atmosphere belt pattern
- auroras at the poles
- good images of the satellites and rings
96
Cassini-Huygens Spacecraft
- 1st spacecraft to orbit Saturn, explored rings and satellites
- dropped into orbit July 1, 2004
- Cassini was built by NASA, and the Huygens probe was built by the European Space agency
- designed to use as little fuel as possible, depends on gravity assists from other solar bodies
97
Plutonium nuclear reactor
- part of Cassini-Huygens
| - nuclear reactor fuel cell
98
Saturn: New Horizons
-cut through orbit of the Saturn system as it sped down toward Pluto
99
Saturns heat
- infrared observations show that Saturn is radiating 1.8x as much energy as it receives from the sun
- must be hot inside cause heat is flowing out from interior
100
Friction and Compaction
The friction of the falling droplets and the compaction of them in the core heat up the planet.
heating is similar to when a star contracts
101
Saturn - Composition
Thick atmosphere with lots of cloud
- Same composition of Jupiter but it is much less dense (contains more hydrogen - the lightest element)
- Saturn has a small rocky core - consist of metallic hydrogen inner mantle and rest is liquid hydrogen.
102
Saturn - atmosphere composition
91% hydrogen, 6% helium
Few but very strong/cold winds
103
Belt and zone circulation
Same as Jupiter
Zones are higher clouds formed by rising gas
Belts are lower clouds formed by sinking gas
104
perfectly symmetrical magnetic field
Saturns magnetic poles exactly match the rotational poles, thus it's the only planet with a perfectly symmetrical magnetic field
-this like other planets magnetosphere is an efficient deflector of the solar winds
105
Credit for the discovery of Saturn
Galileo
106
Credit for the discovery of Saturn's rings
Huygens
107
Cassini Division
The big gap between Saturn's A and B rings - caused by gravitational disturbances by Mimas (Saturn's moon/satellite)
- Very "dirty" - more dirt than ice
108
Mimas
one of Saturn's satellite
109
Resonance
The ring particles orbiting in the gap between Saturns rings (with Mimas) are over time gravitationally nudged into new orbits, thus largely clearing out the section
110
Where do Saturn's rings lie
EXACTLY above Saturn's equator
-only visible because the planets 27 degree axis
111
Spokes
- Discovered by Voyager 1.
- Dark radial features that move in curious patterns on the B ring
- Disappeared and appeared again: Seems to be a seasonal phenomena
112
Water ice
Composition of Saturn's rings are composed of 95% water ice
113
Shepherd satellites
Satellites that tightly associate with the rings were thought to act as stabilizers
-will at least temporarily stabilize the orbit as it will orbit just outside a ring of Saturn and due to its mass, it will orbit a little slower, the gravitational force of the satellite will drag the particles back toward it thus controlling the energy of the particles stabilizing there orbit
114
Titan (Saturns largest moon)
- The main atmospheric component is nitrogen (98.4%) (like earth)
- Larger than Mercury
- The surface is composed of water, ice, and rocky materials, also of an intriguing pattern of irregular bright and dark regions that look like continents and oceans
- 1.5x the surface pressure of the earth
- Surface temperature is -179 degrees - caused by the haze of the atmosphere - meaning the tiny chance of any biological life - methane not created by biological life.
115
Cryovolcanoes
Volcanoes on Titan which their product is not hot lava but cold water and ice.
116
Mimas and Lapetus (Saturn's satellites)
- Mimas: Enormous crater impact on the top right
| - Lapetus: Also have a big crater impact, with an equatorial ridge that crosses the equator.
117
Enceladus
satellite of Saturn
-Frictional kneading and wobbling creates enough heat to make liquid water
- orbits very close to Saturn
- travels at a high speed
118
Prometheus and Pandora
Shepherd satellites which stabilize the F Ring.
119
Gas Giants
Refers to Jupiter and Saturn
Composed of H and He
120
Ice Giants
Refers to Uranus and Neptune
Composed of Water, ammonia, and methane
Both 4 times larger than Earth, circled by dark rings
121
Discovering/naming Uranus
- oldest of the Greek god names suggested by Bode
- they did not want to call it Herschel after the English king
- controversy as he discovered it but it had been discovered years earlier by the Europeans
122
Missions to Uranus and Neptune
In 1986, Voyager 2 flew past Uranus and in 1989 flew past Neptune.
123
Kuiper Belt Location
A region of the solar system that begins just beyond the orbit of Neptune and contains small bodies made mostly of ice.
Neptune is the closest planet to the belt and its gravitation largely affects the belt.
124
Stratosphere
- Upper stratosphere of Uranus's atmosphere
| - Part of the belt-zone cloud patterns of Uranus
125
Troposphere
- the lower troposphere is more interesting
- temp rises rapidly from top to bottom of the layer
- haze or cloud layers of very specific composition appear at different heights through the troposphere
- Temp gradient plus rotation gives rise to a belt-zone cloud pattern
126
Titania
Uranus' largest satellite
127
Conduction
The direct transfer of heat from one substance to another substance that it is touching.
128
Convection
The transfer of heat by the movement of a fluid or gas
129
Radiation
Energy that is radiated or transmitted in the form of rays or electromagnetic waves or particles.
130
Satellites of Uranus
Titania, Umbriel, Miranda, Puck, Ariel
- All 5 contain frozen water
- Dark surfaces
- All 5 contain frozen water
131
Satellites of Neptune
Neptune only has 2 satellites - Triton and Nereid
Triton is nearly circular, but it travels backward – opposite to that in which Neptune
rotates. This makes Triton the only large satellite in the Solar System with a
retrograde (backward) orbit!
Completely stable rn but maybe not in the future
132
The surface imaged from Voyager 2 is divided into three main regions
Uhlanga Regio
(polar)
Monad Regio (eastern equatorial)
Bubembe Regio (western equatorial).
133
Viviane and Namazu Macula
Plumes of dark material made by nitrogen geysers in Uhlanga region
134
Tuonela and Ruach
walled plains or "lakes" such as Tuonela and Ruach in Monad region
135
Trans-Neptunian objects
- these are any sized objects in the solar system that orbit the sun at a greater distance on avg than Neptune
- include everything in the Kuiper Belt and the Oort Cloud
136
Pluto's classification
- demoted in 2006 from a 'proper planet' to a dwarf planet
- this was done because too many Pluto like planets were being discovered
Eris, Ceres, Makemake, and Haumea are also in this category
137
Small Solar System Bodies (SSSBs)
Any astronomical object in the solar system that doesn't meet the international astronomical union (IAU) definition of a planet or dwarf planet--includes moons, asteroids, comets, and meteoroids.
BAD DEF, USE TNO's instead
138
how often does Pluto swing inside the orbit of Neptune?
every 248 earth years
| -stays here for 20 yrs
139
Blink comparator
A machine that allowed to look through a microscope at a small spot on one plate and then flip of a lever to see the same spot on the other plate.
Tombaugh used this to discover Pluto by seeing if any objects moved from the first plate compared to the second plate.
140
Tombaugh Regio
Bright, heart-shaped region on Pluto
141
Sputnik Planum
A smooth plain in the bright, heart-shaped region of the Tombaugh Region is made out of nitrogen, carbon monoxide, and methane
- It suggests that the ice are very young and are geologically active thus no cratering
142
Plutos 4 tiny satellites
-Nix, Hydra, Kerberos and Styx
Discovered by Hubble space telescopes
143
Scattered disc
Objects like Eris that have wild and random orbits out at the edge
of the Solar System are said to make up a Scattered Disc
- since the scatter disc can be said to start w in the Kuiper belt
- evidence most short term comets come from here
144
Amino acids
Most basic carbon components, building blocks
145
Nucleus of comets
dust/frozen gas center typically 1-10km in diameter
146
The Coma of a comet
- atmosphere surrounding the nucleus of the comet
| - this is a result of the sun warming the solid ice surface of the nucleus vaporizing it producing the coma
147
The tail of a comet
-coma becomes larger and brighter as it nears the sun, as comet approaches sun, part of coma becomes elongated tail
148
Head of the comet
Together, the coma and the nucleus form the head of
| the comet
149
Dust tail
-small (smoke-sized) dust particles that sputter off the nucleus
curves toward comet's orbit - made up of dust particles that reflect light.
-usually easiest to see from earth
150
Ion tail
longer blue-colored
- made up of charged glowing gas
- pushed straight away from the sun by the solar wind, while bright dust tail traces the curved orbit
151
Meteor shower
occurs when Earth intersects a comet's orbit and comet particles burn up as they enter Earth's upper atmosphere
152
Which direction do tails point?
tails directed away from the sun
- gas (ion) tails points away from the sun
- dust tail curves toward the orbit path
153
Long-period comets
take more than 200 years to orbit the sun - sometimes thousands or millions of years to orbit the sun once
154
short period comets
the orbital period of 200 years or less
- do not venture past pluto at aphelion, according to Kepler's 3rd law
- dynamical lifetime of a typical short-period comet is 1/2 million yrs
155
Life & death of comets
1. The nuclei are losing mass at rates that cannot be sustained for very long.
2. The active comets are under the gravitational control of the planets - thrown into sun, thrown out of solar system, or collided with one of the planets
156
Oort Cloud
- long period comets come from here
- never been seen
- swarm of icy bodies orbiting the sun at a distance of more than a light yr
157
The Kuiper Belt comets
Significant for 2 reasons for comets:
1. Objects in the Kuiper belt are believed to be the primitive remnants of the early accretional phase of the solar system.
2. Kuiper belt's overlap with the scattered disk is believed to be the source of at least some short-period comets
158
Origin of Comets
- Short-period comets are from the Kuiper Belt & Scattered disc
- Long-period comets are from the Oort Cloud
159
Gliese 710
The star which will shock the Oort cloud objects to land in the inner solar system.
160
Comet Halley
The short-period comet was discovered in 1705 that repeats itself every 76 years and last appeared in 1986.
- Giotto approached with a close flyby, crossing into the coma, produced photos of the nucleus
- Surface is covered with a layer of organic material.
161
Comet Borrelly
Surface is dark, with materials of carbonaceous chondrites
- Studied by Deep Space 1 in a close approach
- Doubled our knowledge of comets overnight
162
left foot and right foot
- Comet wild 2
| - giant impact craters that resemble foot prints
163
Deep impact
- Comet Tempel 1
- rough time justifying a budget
- spent more than $300M to send a probe to smash into Comet Tempel 1 at 37,000km/h
- probe vaporized upon impact
164
Rosetta spacecraft mission
- the visit of the Tchouri / "67P Tchourioumov-Guerassimenko" comet is currently ongoing
- entered orbit around the comet in 2014
- the lander called Philae, performed a soft landing on the surface of the comet and returned data from the surface
165
First predicted return of any comet
Halley's Comet
166
The daylight comet
- appeared a few weeks before Halley's and was the brighter of the 2
- had a long tail and was visible the same times as the sun
167
Great southern comet
Was bright enough to cast shadows and to remain visible even when the sun was above the horizon
-1st comet to be properly photographed
168
Hale and Bopp
-second brightest comet was discovered in 1995 by Hale and Bopp
had it come as close as Hyakutake, it would have cast
shadows
169
Life/life-form
Living matter that utilizes energy from its environment to survive and create offspring.
Life-forms reproduce, & carry out processes by which they grow and live.
170
DNA
- a form of nucleic acid
- carries genetic info of all organisms (bacteria also has this)
- primary role is to contribute the info required for production to regulate chemical reactions to cells
171
RNA
a nucleic acid that translates the code stored in DNA, carries out the coded instructions given by DNA
172
Cells
The smallest unit that has the properties of life and all organisms are composed of 1 or more of them
173
Nucleic acids and proteins
Nucleic acids: macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus
Interaction between them makes up the ability of life to reproduce and regulate within cells
174
Carbon-based life on Earth
all earth life is carbon-based
Carbon atom bonds easily to other atoms, enables it to form long, complex stable chains that are capable of extracting, storing, & utilizing energy.
Unlikely existence of silicon people due to weak bonds
175
Natural selection
The process in which variation in the DNA gives a particular species a survival advantage over the other species. Thus, this type of species will survive and reproduce while the weaker species will die & become extinct
176
Mutant
- Random change in genes/chromosomes produced in offspring that carry mutations (mutant genes)
- the carrier is called a mutant
- in rare cases gives the species a new survival advantage but often make no diff
177
Life (textbook definition)
Cellular organisms
1. that are carbon- and water-based
2. that contain genetic information sufficient to reproduce
3. that possess the abilities to undergo metabolism;
4. that respond to stimuli
5. that adapt (through natural selection) to their environment in successive generations.
178
Primordial soup
The rich mixture of organic compounds in ancient seas
179
Prokaryotes
- all oldest fossils
- poorly defined, simple, single-celled organisms, lacking complex internal structures such as a nucleus
- contained entire DNA in each cell but it's poorly defined
180
Eukaryotes
- larger more complexed structure with nucleus and organelles membrane bound
- DNA nicely defined in the nucleus developed from prokaryotes
- live by respiration using oxygen for energy
- Are Sexual vs Asexual prokaryotes
181
Cambrian period
aka Cambrian explosion
-1/2 billion yrs ago a change in earth climate, life exploded into a wide diversity of complex organisms
182
The three questions leading to life on other planets
1. Could life originate in another world if conditions were suitable?
2. Will life always evolve toward intelligence?
3. Are suitable conditions so rare that life almost never gets started?
183
Most important requirements of life
presence of liquid water
It not only is part of the chemical reactions of life but also a medium to transport nutrients and wastes within the organism. Moderate temperature --> liquid water
184
life on Moon
Airless, even with the possibility of frozen ice at poles, never had liquid water on its surface. Water would boil away rapidly.
185
life on Mercury
Airless, cannot have liquid water on its surface for a long period of time
186
life on Venus
Even with some traces of water vapor in its atmosphere, its surface is too hot for liquid water to survive.
187
life on Europa
The satellite of Jupiter, Europa has the best chance to sustain life.
It seems to have a liquid water ocean below its icy crust, with minerals dissolved in the water that would provide a rich broth of possibilities for chemical evolution.
However, it is not promising because of its instability and it may have once been frozen completely which would prevent life from developing.
188
life on Ganymede
Runner up of the possible destination of life. As the satellite of Jupiter, it has a liquid ocean (not ice). Still behind Europa in terms of the possibility of life.
189
life on Titan
Saturn's satellite has an atmosphere of nitrogen, argon, and methane, and may have oceans of liquid methane and ethane on its surface. It has a similar resemblance to early Earth 4.6 billion years ago.
190
Liquid water on Mars
There's a big belief that water once existed on Mars for a longer period of time than it took for life to evolve on Earth.
191
Life on Mars
Mars has the highest potential to have developed life (not intelligent, just life).
It currently undergoes intensive investigation by large numbers of spacecraft - including the Curiosity and Opportunity rovers, as well as the European Space Agency (ESA)'s Mars Express.
In 2004, ESA discovered signs of methane in the atmosphere. Methane can be the result of volcanic activity, breakdown of carbon dioxide, or most importantly, it can be the product of active biological activity - just like on earth.
192
Habitable zone
Ecosphere
- distance around each star which a planet has temperatures that permit the existence of liquid water
- Size of habitable zone dependent on temp of the star
193
Search for Extraterrestrial Intelligence (SETI)
The US Congress once canceled NASA's funding in the 1990s, and it is now supported by private funds.
The controversy has to do with the fact that the discovery of intelligent life in other worlds has nothing to do with science.
194
Goldilocks zone (hint: another term for..)
aka Habitable zone
195
Kepler-186f
A red dwarf star was discovered by the Kepler mission - 491 light-years from Earth.
radius similar to Earth and sits within the habitable zone
196
Kepler-452b
A potentially Earth-like planet (1.6 times the size of Earth) in the habitable zone of a 6 billion years old star which is like the sun, but a little bit brighter. Therefore, the Kepler-452b is more like Venus than the Earth.
This is considered one of the most important exoplanet discoveries.
197
Tau Ceti e
An exoplanet orbiting around a sun-like star. It is only 11.9 light-years from the Sun, and is twice the size of earth, sits within the habitable zone. If it has an earth-like atmosphere, it will have a surface temperature of 68 degrees Celsius.
198
how long will we have to wait for a reply from space 10 light yrs away
20 years
| -this is from radio communication to space
199
Mass extinctions
The 5 particularly devastating events in the past 500 million years. They all have the same characteristics
200
Common characteristics of mass extinctions
1. A very short period of catastrophism.
2. Global context
3. Disturbance in both marine and terrestrial environments
