Astronomy Review (Chapter 1-5)

Geocentric Perspective

The belief that earth is the center of the universe

Ecliptic

The path of the Sun on the celestial sphere, which runs through the center of the zodiac.

Constellations

Sectors in which the celestial sphere is organized, consisting of 88 different constellations.

Heliocentric Cosmology

The theory that the planets, including Earth, orbit around the Sun.

Kepler's Laws of Planetary Motion

Three fundamental laws that describe the behavior of planets in their orbits.

Newton's Laws of Motion

Three laws that govern the motion of objects, including the relationship between force and acceleration.

Newton's Universal Law of Gravitation

The law that relates the gravitational force between two objects to their masses and distance.

Orbits

The paths followed by objects in space, such as satellites and planets.

Coordinate Systems

Systems used to locate objects on the celestial sphere, such as latitude and longitude for Earth and right ascension and declination for the celestial sphere.

Seasons

The cycle of seasons on Earth caused by the tilt of its axis of rotation.

Calendar

Systems used to reconcile the lengths of the day, month, and year, such as the Gregorian calendar.

Phases of the Moon

The changing angles of the Moon's illumination by the Sun, resulting in different phases.

Tides

The twice-daily ocean tides caused by the Moon's differential force on Earth's crust and ocean.

Eclipses

Phenomena where the Moon or Earth casts a shadow on the other, resulting in solar or lunar eclipses.

Electromagnetic Spectrum

The range of wavelengths of electromagnetic radiation, including gamma rays, X-rays, visible light, and radio waves.

Spectroscopy

The study of the interaction between matter and electromagnetic radiation, used to analyze the composition of celestial objects.

Structure of the Atom

The composition of atoms, consisting of a nucleus with protons and neutrons, and electrons orbiting the nucleus.

Formation of Spectral Lines

The process by which atoms absorb or emit photons of specific energies, resulting in spectral lines.

Emission line

A line in the spectrum that is produced when electrons move from a higher energy level to a lower one, resulting in the emission of photons.

Absorption line

A line in the spectrum that is produced when electrons absorb photons and move to higher energy levels.

Spectral lines

Unique patterns of lines in the spectrum associated with the characteristic set of energy levels of each atom, allowing astronomers to determine the presence of elements in stars and clouds of gas and dust.

Ground state

The lowest energy level of an atom, where the electron is in its least energetic orbit.

Excited state

When an electron is in an orbit other than the least energetic one possible, causing the atom to be in an excited state.

Ion

An atom that has lost one or more electrons, resulting in it being called an ion.

Ionized

The state of an atom that has lost one or more electrons and is therefore ionized.

Doppler effect

The shift in the wavelength of a spectral line towards the blue or red end of the spectrum, depending on whether the atom is moving towards or away from the observer, respectively.

Radial velocities

The velocities of objects along the line of sight, which can be measured using the Doppler effect.