Chapter 3: The Universal Context of Life Flashcards
What is light?
Electromagnetic radiation.
Is radiation a form of energy?
Yes.
At what speed does radiation go?
At the speed of light.
Is electromagnetic radiation a wave or a particle?
A wave.
Pre-defined packages of energy are called what?
Quanta
What is Planck’s constant?
h=6.626x10-34 Joule sec.
What is the spectrum?
The dependence of luminosity on wavelength.
Shorter wavelength cause what type of frequency?
Higher frequency.
Opaque objects do what to radiation?
Absorb and block all radiation hitting them.
What do transparent objects do to radiation?
Allow radiation to pass through them.
What is a blackbody?
An object that is completely opaque to all radiation.
On the blackbody spectrum, hotter things are what color?
Bluer.
Describe what hotter things look like on the blackbody spectrum.
Always brighter at all wavelengths.
How do you raise the orbital of an electron?
Add energy by hitting it with a photon. The photon is then converted into energy.
What is the process of raising the orbital of an electron called?
Absorption.
What is the process of lowering the orbital of an electron called?
Emission.
How does the orbital of an electron get lowered?
Electron releases energy as light.
How do we measure how fast celestial objects are moving?
Using the doppler effect.
How does the doppler effect work?
A moving object is partly catching up to its own light waves, or moving away from them.
Light emitted by a moving object will appear blue-shifted if…
The source is moving towards the observer.
Light emitted by a moving object will appear red-shifted if…
The source is moving away from the observer.
What did Vesto Slipher discover?
That almost all galaxies were red-shifted - they were moving away from us.
What did Hubble discover?
All galaxies are moving away from each other. - Meaning that there is no center - the observer would always see themselves as the center.
What is a comet?
A relatively small and ice-rich object that orbits a star.
What is an asteroid?
A relatively small and rocky object that orbits a star.
What is the cosmic microwave background?
A faint glow of radiation left behind when the universe expanded and cooled with time.
Describe matter at the time of the big bang.
All of the matter in the universe was compressed to extremely high temperatures and density.
What are two major lines of evidence for the big bang theory?
- Cosmic microwave background. 2. Overall chemical composition of the universe.
