Honors EES Unit Two: Astronomy
The evidence used to support the Big Bang
Cosmic Microwave Background Radiation (CMBR) and the Red Shift
When the Universe began
13.7 billion years ago
Solar eclipse
An eclipse in which the sun is obscured by the moon.
Astronomy
The branch of science that deals with space
Gravity
The force that attracts a body towards the center of the Earth
Geocentric
Having or representing the Earth as the center of the solar system
Heliocentric
Having or representing the sun as the center of the solar system
Retrograde motion
The apparent change in the movement of a planet
Lunar eclipse
When the moon passes directly behind the Earth
Solar eclipse
Umbra
The shadow cast by an opaque object, totality in a solar eclipse
Penumbra
A partially shaded outer region of a shadow
Perihelion
The point in the orbit of a planet when it is closest to the sun
Aphelion
The pound in the orbit of a planet when it is farthest from the sun
Apogee
The point in the orbit of the moon when it is farthest from Earth
Perigee
The point in the orbit of the moon when it is closest to the Earth
Precession
A slow motion of Earth’s axis that traces out a cone over a period of 26,000 years
Nutation
The periodic variation in the inclination of a subject
Terrestrial planets
The name given to the four inner planets: Mercury, Venus, Earth, and Mars.
Gas planets
A planet composed mostly of helium and hydrogen
Kuiper belt
Region of the solar system beyond the orbit of Neptune
Oort Cloud
A spherical region of comets that surrounds the solar system
Satellite
An artificial body placed in orbit to collect info for communication
Telescope
A device built to observe distant objects by making them appear closer
Johannes Kepler
German astronomer who first stated laws of planetary motion (1571-1630)
Elipse
An obscuring of light from one celestial body by the passage of another
Kepler’s First Law
The path of the planets about the stars is elliptical in shape with the sun in the center
Kepler’s Second Law
A planet moves faster when it is closer to the sun
Kepler’s Third Law
Every planet has its own unique orbiting period
Meteorite
A meteor that travels through the Earth’s atmosphere and hits the ground
Electromagnetic Spectrum
The range of wavelengths over which radiation extends
Nuclear fusion
A nuclear reaction in which atomic nuclei with a low atomic number fuse to from a heavier nucleus with the release of energy
Core (Layers of the sun)
The center of the sun and the hottest part of the sun
Radiative zone (Layers of the sun)
Where energy is mainly transported to the exterior by radiative diffusion
Convection zone (Layers of the sun)
Where energy is transported by convection
Chromosphere (Layers of the sun)
Normally invisible and can only be seen during a solar eclipse
Photosphere (Layers of the sun)
The outer shell where light is radiated
Corona (Layers of the sun)
The aura of plasma that surrounds the sun and other stars
Solar flare
A brief eruption of intense high-energy radiation from the sun’s surface
Aurora
A natural electrical phenomonon that causes streamers of red or green light in the sky
Light year
Distance light travels in one year.
Nebula
A cloud of gas and dust in outer space
Red Giants
A large star of high luminosity and low surface temperature
Neutron star
A celestial object of a very small radius and very high density
Black hole
A region of space having a gravitational field so intense no matter can escape
Edwin Hubble
An American astronomer
The Doppler effect
The change in frequency or wavelength of a wave to an observer
Red shift
The displacement in radiation from distant galaxies and objects
Cosmic Microwave Background Radiation (CMBR)
Radiation left from the Big Bang
Hertzsprung-Russell Diagram
A graph relating the surface temperatures and absolute brightness of stars
Barycenter
The center of mass is the balance point between two orbiting bodies.
Neap Tide
When the sun and moon are right angles from the Earth
Spring tide
The tide after a new or full moon