AS101 final exam review

Light

The messenger of energy, measured in joules.

Watt

The unit for measuring light energy flow, equivalent to 1 joule.

Electromagnetic Radiation

Light is composed of electric and magnetic fields.

Wavelength

The distance between successive peaks or troughs of a wave.

Frequency

The number of times per second that a wave vibrates up and down.

Nanometre

One billionth of a metre.

Angstrom

One tenth of a nanometre.

Photon

Particles of light that have a wavelength and frequency.

Planck’s constant

6.626 x 10^-34 joule x second, related to photon energy.

Emission

Energy in matter that can be converted into light.

Absorption

The process where matter absorbs energy in the form of light.

Transmission

The ability of transparent objects to emit light.

Reflection

The bouncing of light off objects in a specific direction.

Temperature

A measure of the average speed of atoms and molecules in a material.

Heat

The transfer of energy stored in a material.

Kelvin

The unit of temperature used by astronomers.

Blueshift

A Doppler shift toward shorter wavelengths caused by a source approaching an observer.

Redshift

A Doppler shift toward longer wavelengths caused by a source moving away from an observer.

Radial Velocity (Vr)

The component of an object's velocity directed away from or toward Earth.

Light Gathering Power

Depends on the surface area of the primary lens/mirror of a telescope.

Resolving Power

A measure of a telescope's ability to distinguish between two close objects.

Sidereal Tracking

The continuous movement of telescopes to compensate for Earth's rotation.

Observable Universe

The part of the universe visible from a specific location in space and time.

Cosmic Expansion

The phenomenon where galaxies appear to move away from Earth, indicating an expanding universe.

Hubble Time

The estimated age of the universe, approximately 14 billion years.

Cosmic Microwave Background Radiation

The radiation that provides evidence supporting the Big Bang theory.

Cosmological Principle

The assumption that the universe is homogeneous and isotropic.

Dark Matter

An unknown form of matter necessary for explaining the universe's structure.

Inflationary Big Bang

A version of the Big Bang theory that includes rapid expansion in the early universe.

Terrestrial Planets

Earth-like planets made of rocks or metals, such as Mercury and Venus.

Jovian Planets

Large gas planets like Jupiter, Saturn, Uranus, and Neptune.

Asteroids

Rocky objects in space, mostly orbiting between Mars and Jupiter.

Exoplanets

Planets located outside of our solar system.

Black Hole

A region in space where the gravitational forces are so strong that nothing, not even light, can escape.

The Chandrasekhar Limit

The maximum mass a white dwarf can have while remaining stable.

Hertzsprung-Russell Diagram

A plot of star luminosity versus surface temperature used to categorize stars.

Albedo

The ratio of light reflected from an object compared to the light received.

Lunar Highlands

Older, heavily cratered regions of the moon composed of low-density rock.

Caloris Basin

The largest basin on Mercury, formed by heavy meteor impacts.

Atmosphere of Venus

Dominated by CO2, with other gases like nitrogen, sulphur dioxide, and traces of hydrochloric acid.

Martian Water Evidence

Indications that liquid water once existed in large quantities on Mars, though now mostly frozen.

Phobos and Deimos

Irregularly shaped moons of Mars, believed to be captured asteroids.