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1-4 Study Guide - Sarah Miller
Our Solar System (ESCI 420)
University of New Hampshire
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How should I work through weekly material?
One possible approach:
Check the ‘Quiz’ section to see if any question responses are due within the next week. If so, make note of them so you’ll more efficiently identify relevant information in your reading and multimedia reviewing. Don’t forget to submit responses before the deadline!
Read through the accompanying study guide for the week. Be ready to take notes on material listed.
View the multimedia content. Note themes, answers to study guide material, general approaches to science, and pay attention to not only what we know but how we know it.
Read the assigned textbook chapters, which are not terribly long. Same marching orders as for multimedia content.
What skills are being practiced in lab? What sorts of calculations are you using to quantify some physical aspect of how we understand the universe or Solar System to work?
ESCI 420: Our Solar System Week 1 Study Guide
- What is the cosmological principle? On what length scales does it apply?
The Cosmological Principle is the idea that astronomers describe as universes or galaxies having no special place or position in the universe
- What is the expression for Newtonian gravity and how is this idea of how gravity works different from the general relativity understanding of gravity in the universe?
Newton’s universal law of gravitation states that every object in the universe attracts every other object with a force that is directed along a line joining them. The force is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
- What is Hubble’s Law? Be able to identify the variables in the equation.
Hubbles law tells us that a galaxy’s velocity grows with distance according to the formula V=H*d Hubbles time is th=d/v Hubbles formula assumes that expansion of space has remained constant V= velocity H= hubbles constant D=Distance
What is a redshift in the light transmitted by galaxies and what does it tell us about the nature of the universe? Redshift is the stretching of the universes effect on wavelengths. The redshift indicates how much the universe has expanded since light left the object we are observing.
What is a parsec? Both the parsec and light-year are frequently used by astronomers when talking about stars and galaxies, so it is useful to be able to convert back and forth between them. A parsec is a little more than 3 times larger than a light year, so converting between them is similar to converting between meters and feet.
What does general relativity tell us about space that, combined with the cosmological principle, explains why light from other galaxies appears red-shifted?
Einstein's theory of general relativity explains why the universe is expanding but has no center of expansion or blast origin. General relativity predicts that space itself is expanding There is no contradiction between general and special relativity
Why do galaxies with high redshifts physically appear to be different from galaxies with low redshifts? Galaxies with a high redshift are much farther away from our galaxy than others. These look different because we are looking back in time to a younger galaxy relative to the rest of the universe the redshift of a galaxy increases with its distance from us Galaxies at such high redshifts look very different from nearby galaxies, in part because the matter was just in the beginning stages of gathering together to form a galaxy (Unit 76). If we look out farther and farther, to earlier and earlier times in the age of the universe, ultimately, we should see a time when the whole universe was packed together at extremely high density.
What evidence do we have of universe expansion?
The evidence we have of universal expansion is that there is a redshift from the wavelengths of light being emitted from far away galaxy's
- Can you apply the Hubble equation to a set of galaxy data to calculate a time when two galaxies were very close together?
Yes, you can easily see when galaxies were far apart from each other. You just need to follow Hubble's formula backwards and use ht hubbles time page 641
The H-R diagram: note the axes, logarithmic scales, how luminosity is reported relative to that of our Sun (normalized) Identify regions on the H-R diagram (except for spectral class):
Where are the highest and lowest mass stars located on the Main Sequence? Compare the observed size range of white dwarf stars with that of red giants.
Could you track a possible path along the H-R diagram for a low or high mass star?
The electromagnetic spectrum is divided into seven broad categories of light. Know the wavelength general order of magnitude for each and examples of each.
Equations E = hν, ν = c/λ (know the variables of each)
Week 3 Study Work Guide
What are the planets in our solar system and what is their order from the Sun? How is mass distributed across the solar system?
What does planet density tell us about their compositions?
Where are the asteroid belt, Kuiper Belt, and Oort Cloud located?
What is the definition of a planet and what distinguishes a planet from a dwarf planet?
What is our best estimate of the age of the solar system?
What evidence supports this age?
What is a half-life? How would you determine it by looking at a graph plotting a decaying parent isotope population as a function of time?
Name several long-lived and several short-lived isotopes useful in dating solar system materials.
What is the chemical composition of an interstellar cloud?
What process(es) dominate(s) at each step? Interstellar cloudàsolar nebulaàplanetesimal formationàmature solar system with planets
What is the accretion process sequence (from snowflake to gravitational collapse)? What forces dominate at each step?
What is the relationship between the likely temperature gradient within the solar nebula and the types of materials condensed from near the sun out to beyond > 50 AU?
What is the ‘snow line’ in the solar system and where is it located? What are the sources of energy for differentiating a planet? What are the possible fates of planetesimals formed in the early solar system? What was the late-stage bombardment and what evidence indicates that it occurred? What are the leading explanations proposed for the formation of Earth’s oceans and atmosphere? What is the T-Tauri phase and why is it relevant to solar system studies? Why do we not observe residual gas and dust between the planets today?
Week 4 Study Work Guide
Identify components describing an ellipse (focus, major and minor axes, eccentricity) and how these correspond to orbits in our solar system.
How is Pluto’s orbit different from that of planets in the solar system? What are Kepler’s three laws of planetary motion?
What is Newton’s equation for gravitational force (for two bodies some distance from one another)?
What are the relationships between orbital velocity, G, m, M, r, and a?
How do velocity and eccentricity determine whether a body remains in orbit around a primary body?
What types of orbits are possible? How are secular and periodic perturbations different? What is resonance? What are tidal forces and how are they generated?
1-4 Study Guide - Sarah Miller
Course: Our Solar System (ESCI 420)
University: University of New Hampshire
