Big Bang Theory
A theory that states that the universe is 13.7 billions years old. A tiny hot spec that started to expand and cool over time.
cosmological red shift
Wavelengths of radiated light that are being constantly stretched (lengthened) as the light crosses the expanding
Radiation that has different wavelengths. Gamma rays with the shortest and radio waves with the longest.
A galaxy that is shaped as a perfect sphere or an elliptical shape that contains the oldest stars. Scientists have estimated that more than half of the galaxies in the universe are ______
A shifting of light from an object towards the red end of the spectrum as the object moves away from earth
One of three types of galaxies. It Looks like a pinwheel from the top and from the side, it looks like a plate with a bulge in the center. The newer stars are on the edge and older ones are closer to the core. Our solar system is part of an ____ ______ and our sun is in the center of an arm.
A group of stars held together by gravity. Open (100's to 1000's) and globular (1000's to millions).
Small rocky bodies in our solar system, most of which orbit the sun between Mars and Jupiter
A very dense celestial body (that is made when a super nova collapses on itself) with a strong gravitational pull.
The change in wavelengths of electromagnetic radiation or sound that occurs because of the movement of the source relative to an observer
When two hydrogen atoms fuse together to make helium. The nuclei of the two atoms fuse together to form a single atom, creating an enormous amount of energy
The time it takes for light to travel in a year. light travels at 300 000km/s so a ______ is equivalent to 9.5 trillion km
The apparent shift of an object against a stationary background due to the change in position of the observer. Closer objects have a bigger shift.
A celestial body that orbits one or more stars, it is large enough that its own gravity holds it in a spherical shape, and is the only body occupying the orbital (elliptical) path
The motion of an celestial body moving all they way around another. (ex. the earth orbits the sun and the moon orbits the earth)