Unit 1: The night sky Flashcards
What is an Astronomical Unit (AU)
The distance from the Earth to the Sun (1.5 x10^8 km)
What is the celestial sphere?
An imaginary sphere that has its poles at the north and south pole
What are constellations?
Random patterns of the stars that humans have interpreted mythologically
What is a galaxy?
A collection of billions of stars, other objects such as black holes, and the gas between them
What is a horizon?
Boundary where the sky meets the ground; Altitude = 0 degrees
What is a local sky?
Where the observer’s horizon is; what the sky looks like where the observer is standing
What is a light year?
The distance that light travels in one year
What is the Proxima Centauri?
The closest star beside our Sun (4.25 light years away from Earth)
What is a star?
A hot sphere of gas containing hydrogen and helium.
What is the solar system?
A collection of stars, its planets, their moons, and other orbiting bodies
What formula is used to calculate how far a light year is?
Velocity = distance/time -> distance=velocity x time
What is a zenith?
The point right above the observers head; altitude= 90 degrees
What is the order of the Universe from smallest to largest: Local supercluster, Earth, Solar System, Milky Way Galaxy, Observable Universe, Local Group
Earth, Solar System, Milky Way Galaxy, Local Group, Local Supercluster, Observable Universe
Earth rotates from what direction to what direction? What direction do stars appear to travel?
West to east; East to west
According to the scientific method, theories
Will be revised if new observations are made that are inconsistent with the theory
