The Moon and Planets; Small Bodies in the Solar System Flashcards
Describe the causes and effects of the atmospheric greenhouse effect and global warming
Sunlight heats the ground (which emits infrared radiation). Certain molecules absorb the radiation so the Earth doesn’t cool off because it can’t escape. Water vapor and CO2 block the infrared radiation because they’re greenhouse gases. Humans add CO2 to the atmosphere= warmer temperature= Global Warming
Describe the impact of human activity on our planet’s atmosphere and ecology
Global Warming
- Climate Change
- Melting icecaps
- Rising sea levels
Explain the scarcity of impact craters on Earth compared with other planets and moons
Earth was heavily impacted by craters just as much as the Moon. Craters destroyed by active geology. Plate tectonics renews the crust. Objects burn up in the Earth’s atmosphere. Erosion
Describe the evidence for recent impacts on Earth
1) Tunguska River in Siberia but no craters (if it penetrates the Earth it would be classified as a crater) because it only damaged the surface
2) Arizona called the Meteor Crater
Detail how a massive impact changed the conditions for life on Earth, leading to the extinction of the dinosaurs
Mass extinction: more than half of the species on our planet died out
Chicxulub: crater that killed the dinosaurs. Airborne material blocked out sunlight. Other results such as the fires and acidic rains led to the extinction of the dinosaurs
Discuss what has been learned from both manned and robotic lunar exploration
Manned- terrestrial planets
Robotic- (terrestrial and) jovian planets
Explain the process of impact crater formation
The projectile penetrates 2-3x its own diameter before stopping; energy as a shock wave and heat
Crater size is usually 10-15x greater the diameter of the projectile
Characterize the orbit of Mercury around the Sun
Highest average orbital speed
Describe Mercury’s structure and composition
The smallest terrestrial planet and planet overall
Greater density than the Moon= made up of 2 very different elements (mass: up to 60% iron-nickel, the rest being silicates)
Weak magnetic field (part of the core is liquid to create the field)
Explain why it’s difficult to learn about Venus from Earth-based observation alone
Surface is not visible b/c of clouds
Compare the basic physical properties of Earth, Mars, and Venus, including their orbits
All about the same size
All terrestrial planets- mostly solid
Provide an overview of the composition of the giant planets
Material: gas (mostly hydrogen and helium), ice, rock (less abundant than ices)
Gas giants- Jupiter and Saturn
Ice giants- Uranus and Neptune (interiors contain more ice)
Describe typical orbits of asteroids
Ellipse oribit like all the planets. Some are in the KB (outside of the solar systeml has the comets, asteroids, and other small bodies of ice adn rock)
Characterize the general physical appearance of comets
Comet: small chunk of icy material that develops an atmosphere as it approaches the Sun (has a very faint nebulous tail). Not spectacular; very faint. Appear at unpredictable times. Visible for a couple weeks to months
Explain what a meteor is and why it is visible in the night sky
What: a small piece of solid matter that enters Earth’s atmosphere and burns up, popularly called a shooting star because it is seen as a small flash of light. a small rocky or metallic body in outer space.
Why: It’s heating up and it’s getting hot as it’s traveling through the air.
Describe the origins of meteor showers
Ash, dust, debris from the comets/rock/asteroids. Falling fast which makes it appear on fire and glowing like.
Many meteors appearing to radiate from one point in the sky; produced when Earth passes
through a cometary dust stream.
A sudden burst of meteor activity usually lasts several hours. Often named by the constellation from where the radiant is located
Explain how the study of meteorites informs our understanding of the age of the solar system
Includes oldest and most primitive material
Classifications of meteorites: iron, stones, and stony-irons (obvious which type they fall into)
Describe the motion, chemical, and age constraints that must be met by any theory of solar system formation
Motion constraints: most planets rotate in the same direction as they revolve. Most moons orbit counterclockwise. Besides comets and other TNOs motion is defined by a disk or frisbee shape. Exceptions include the retrograde rotation of Venus
Chemical constraints: Jupiter and Saturn have the same compositions (mostly hydrogen and helium). Comets in the Oort cloud and TNOs in the Kuiper belt are icy, asteroids are rocky w/ dark, carbon-rich material. Temperature sequence with planets’ position to the Sun. Exception w/ water on Earth and Mars.
Age constraints: radioactive dating. Age of building blocks= age of planetary system
Summarize the physical and chemical changes during the solar nebula stage of solar system formation
The solar system formed about 4.5 B years ago. Rotating cloud of vapor and dust collapsed under its own gravity, making the material fall towards the center and become more hot and concentrated. Solar nebula began to rotate faster due to angular momentum. Faster materials collapsed into a disk to revolve around the center, which explains the motions of the solar system. When gravitational energy faded tha nebula cooled, but the center formed a star where it maintained its own energy. Turbulent motions and magnetic fields drained its angular momentum and therefore its spin. Some material fell into the growing star and the disk stabilized. Disk cooling produced compounds (liquids and solids) from gases. First solid materials were metals and rock-forming silicates. Temperature sequence (cool temp= oxygen could combine w/ hydrogen to form water= ice)
Explain the formation process of the terrestrial and giant planets
Terrestrial: Grains condensed to form planetesimals
Accretion: when planetesimals are large enough to attract their neighbors gravitationally and grow in the process
Protoplanets: not quite ready for primetime planets
Planetesimals accelerate to combine with the protoplanet, heating the protoplanet
Planetary differentiation: heavier materials sink to the bottom and lighter materials float to the top
Giant: Protoplanets attracted gas. Heated by contraction, but were too small to raise core temperatures. Gradually cooled. Less gas was captured by Uranus and Neptune which is why they have icy and rocky cores.
Describe pseudoscience and give some examples
Pseudoscience is an idea of different methods and concepts that falsely use science as validation of its effectiveness
Examples: astrology, numerology, hypnosis
Explain what scientists mean by a hypothesis, theory, and law
Hypothesis: an explanation that can be tested over and over again. They explain the “how”
Theory: an explanation of a phenomenon supported by facts. Theories start out as hypotheses. They explain the “why”. Cannot turn into a law
Law: principles that can be used to predict processes in the natural world. They explain the “what”
All based on observations
Explain why science poses no threat to religion and how many scientists can be – and are – very religious as well
Science and religion have coexisted for a while. About 40% of scientists are religious. Only a very small percentage of religious people are “anti-science”.
Explain the northern lights
The direction of the solar wind is changed by the Earth’s magnetic field and is funneled into the North and South poles. The solar wind molecules crash through the atmosphere and excite the electron molecules. These electrons move up (absorb light) and down energy levels to emit light, which produce the lights we see at the North pole.
Where are most of the asteroids in our solar system?
Between Mars and Jupiter; the asteroid belt
Kuiper Belt
a disk of debris at the edge of our solar system; beyond Neptune
What kind of object is Pluto?
Kuiper belt object
Oort cloud
sphere of widely spaced comets; the large spherical region around the Sun from which most “new” comets come; a reservoir of
objects with aphelia at about 50,000 AU
Describe Venus’ atmophere
Most of the atmosphere is CO2. It’s the hottest planet because of the greenhouse effect, which means it has few craters. It spins backwards.
What is the “Runaway Greenhouse” effect?
The greenhouse effect on Earth worsens to the point it looks like Venus
Why does Io have volcanic activity?
As Io revolves around Jupiter it’s closeness determines its volcanic activity. As Io gets closer to Jupiter, Jupiter’s tides evoke more heat from Io, but as Io gets farther away there is less volcanic activity.
Describe the criteria of a planet
1) Orbits a star
2) Approx. round
3) Not a star or moon
4) Nothing big in its orbit
Describe a comet
a “dirty snowball”; 2 tails: gas and dust. The solar wind blows gases out. The closer to the Sun the longer the tail. The position of the comet in its orbit depends on where it is in its tail development.
Asteroid
a stony or metallic object orbiting the Sun that is smaller than a major planet but that shows no
evidence of an atmosphere or of other types of activity associated with comets
Near-Earth Asteroid (NEA)
an Earth-approaching asteroid, one whose orbit could bring it on a collision course
with our planet
Near-Earth object
a comet or asteroid whose path intersects the orbit of Earth
Nucleus (of a comet)
the solid chunk of ice and dust in the head of a comet
Exoplanet
a planet orbiting a star other than our Sun
Iron meteroite
a meteorite composed primarily of iron and nickel
Stony meteorite
a meteorite composed mostly of stony material, either primitive or differentiated
Stony-iron meteorite
a type of differentiated meteorite that is a blend of nickel-iron and silicate materials
