Chapter 2: The Science of Life in the Universe Flashcards
What is the name of the path that the sun takes?
Ecliptic.
How do the planets generally move?
From west to east.
Planets sometimes show what kind of motion?
Retrograde motion.
From what direction do objects rise and set?
They rise in the east and set in the west.
Who found out that the earth was spherical? When was it?
Aristotle. 350 BCE.
Ancient scientists of the geocentric model referred to what as epicycles?
The double spinning motion that attempted to explain retrograde motion.
What did Copernicus give to the field? (5)
- He simplified the geocentric model. 2. Sun was at the center. 3. All planets orbit the sun. 4. Earth rotates. 5. Uniform circular motion.
What is Kepler’s First Law?
The orbits of the planets are ellipses with the sun at one focus.
What is Kepler’s Second Law?
The straight line between the sun and a planet sweeps out equal areas in equal times.
What is Kepler’s Third Law?
The square of a planet’s orbital period P (measured in years) is equal to the cube of the semi-major axis A of its orbit (measured in AU). P(^2)=A(^3).
What is an orbital period? What is it for Earth.
The duration of one orbit (e.g. one year for Earth).
What does 1 AU mean?
1 astronomical unit.
What does 1 AU designate?
The distance from the Sun to the Earth.
What did Galileo do for the field?
- Invented the astronomical telescope. 2. First to use it to look at the sky and publish about it. 3. Breakthrough technology leads to new data revolution.
Who essentially disproved the geocentric model?
Galileo.
What else did Galileo discover? (2)
- Phases of Venus. 2. Tied to angular size and position relative to the sun.
How did Galileo essentially disprove the geocentric model? (2)
- Venus tied to solar orbit. 2. We would never see illuminated side in geocentric model.
Who solved the parallax problem?
Galileo.
What is the solution to the parallax problem?
The stars are far away so the parallax must be tiny.
Who came up with the heliocentric model?
Copernicus.
What explains planet, moon, comet, asteroid, and stellar orbits?
Gravity.
What two things did Einstein contribute to the field?
- Gravity is woven into the fabric of space-time. 2. General relativity replaces Newtonian gravity.
What explains apparent retrograde motion?
The planets do not actually change direction but appear to when they are passed by another planet closer to the sun (the planets closer to the sun move faster than those further away from the sun).
