Key Concepts
Explain the four steps of the Scientific Method.
1. Observe nature
2. Create a hypothesis
3. Use it to make a prediction
4. Test your prediction
He formulated Kepler's laws of planetary motion based on Brahe's data.
Johannes Kepler
What are Kepler's Laws?
1. Orbits of the planets are ellipses with the sun at one focus
2. A line segment joining a planet and the sun sweeps out equal areas during equal intervals of time.
3. The square of the orbital period of a planet is proportional to the cube of the semi-major axis of its orbit. (p^2 = a^3)
How many degrees is the Earth's axial tilt?
23.5 degrees
Sidereal vs. Synodic
Sidereal refers to the position of stars
Synodic refers to the alignment of celestial bodies (lunar cycle)
A phenomenon where an astronomical body always shows the same face to the object it orbits is referred as ______ _______.
Tidal Locking
He was known for his accurate astronomical observations and data collection in the pre-telescope era.
Proposed by Copernicus, what was the model of the solar system where the sun is at the center and planets orbit around it?
Heliocentric Theory
How many hours are in a Solar day?
24 hours
Solar eclipse vs. Lunar eclipse
Solar elipse - the moon blocks the sun
Lunar eclipse - the moon is in the shadow of the Earth
Occam's razor
He proposed the heliocentric model (sun in the center) of the solar system.
Nicolaus Copernicus
The speed at which light travels in a vacuum, approximately 3 x 10^8 m/s.
The Speed of Light
How many hours are in a Sidereal day?
23 hours and 56 minutes
Explain the altitude-azimuth (alt-az) coordinate system.
Alt-az is local and fixed to a place on the earth,
altitude - angle up from horizon
azimuth - angle to the right of North
______ is a recognizable pattern of stars in the sky.
Asterism
He was the first to use a telescope for astronomical observations, further supporting the heliocentric model.
Galileo Galilei
Phenomena observed in the light from stars and galaxies that indicate their movement relative to the Earth
______ indicated moving away
______ indicated moving slower
Redshift, Blueshift
What does the word constellation refer to?
A group of stars forming a pattern, and the surrounding area of the night sky.
Right ascension (R.A.) and Declination (Dec. ) coordinated are fixed to _____ _____, with the Earth spinning at the center.
Distant Stars
R.A. is the angle to the left of zero (hours/mins)
Dec. is the angle up from the celestial equator
The apparent path of the sun across the sky, which also defined the plane of the Earth's orbit around sun
Ecliptic
He developed the laws of motion and universal gravitation, laying the foundation for classical mechanics.
Isaac Newton
Why do we have leap years?
It occurs every four years, because a calendar year is not a whole number (365.25 days)
What is Spectroscopy?
The study of the interaction between light and matter, revealing the composition of stars through their unique absorption and emission spectra.
Spectroscopy, specifically the study of Blackbody spectrums, led Einstein to say that light is made of _____.
Photons