Topic 3- Earth in the Universe Flashcards
What kind of radiation found in the universe supports the Big Bang Theory?
long-wavelength background radiation (actually, microwaves) come from all directions of the universe
What is electromagnetic energy?
various types of waves that transmit energy through space
What is the Doppler Effect?
the shifting of wavelengths
What is a red shift Doppler Effect?
when Earth and other celestial objects are moving apart
The farther away a galaxy is from Earth, the greater the ____ shift.
red
What is a galaxy?
a collection of billions of stars and various amounts of gas and dust held together by gravity
What shape is our galaxy, the Milky Way?
spiral-shaped
What is a star?
a large ball of gas held together by gravity that is luminous and produces a lot of energy (not all stars)
What is nuclear fusion?
the combining of nuclei of smaller elements to form the nuclei of larger elements with some of the mass being converted to energy
In what conditions can nuclear fusion occur?
extremely high temperatures and high pressure conditions. Ex: inside a star
What is luminosity?
the actual brightness of a star or rate of total energy emitted compared to the Sun
Most stars are much _____ than Earth, but not all stars.
bigger
What are main sequence stars?
average size, higher temperatures, high densities
What are giant stars?
red, orange, and yellow giant stars. high luminosity, late stage in the evolution of medium to small stars
What are Super Giant stars?
highly luminous, late evolution of stars. they explode, creating supernovas. they are the hottest in temperatures
What are White Dwarf stars?
small stars (Earth size). they are hot in surface temperature and have a low luminosity. last stage of shining
What are Black Dwarf stars?
dead stars- the stage after white dwarfs. there are many black dwarfs
What do stars originate from?
clouds of gas and dust molecules
What is a solar system?
the sun and all objects that orbit the sun under its gravitational influence
Do the planets share their environments with large objects?
no
What is an asteroid?
solid, rocky and/or metallic body that independently orbits the sun. smaller than planets
What are moons?
a body that orbits a planet or an asteroid as those objects orbit the sun
What is a comet?
a dirty snowball (ices of water and methane mixed with rocky or metallic solids). composed of solids that can change to gases when heated.
Why can we see comets in the sky?
solids are released, forming a visible tail in the sky
What is a meteoroid?
small solid fragments that orbit the sun
Why do we see meteors in the sky?
meteoroids burn up or vaporize, leaving a streak
What is an impact crater?
depression in earth’s crust made by a meteoroid
What is an impact event?
planets gravitational forces pull on smaller clumps of matter to cause comets, asteroids, and meteoroids to collide with the planets
What are Terrestrial planets?
close to the Sun and mostly solid. they have small diameters and high densities
What are our solar system’s Terrestrial planets?
Mercury, Venus, Earth and Mars
What are Jovian planets?
far from the Sun and gaseous. they are not solid.
What are our Jovian planets?
Jupiter, Saturn, Uranus and Neptune
How do we determine a planet’s length of day?
the period of rotation around its axis
The planets revolve around the Sun in a _________ direction as viewed from Polaris.
counterclockwise
What is inertia?
the concept that an object at rest tends to remain at rest, while an object in motion tends to stay in motion
When a planet is closer to the Sun, the orbital velocity is
greatest
What is the Big Bang Theory?
the theory that all matter and energy started out concentrated in a small area and, after a giant explosion, matter began to organize into subatomic particles and atoms
