Earth's Magnetosphere and Ocean Tides Quiz

Observing the Local Sky

• Stars, planets, and the moon are visible to the naked eye at night.
• Cultures have named patterns of stars, called constellations.
• Early astronomers used constellations for navigation and calendars.
• Modern astronomers use constellations to define large areas of the sky.
• Stars appear to move across the sky from east to west, but their relative locations remain unchanged (Earth's rotation causes this apparent movement).
• The celestial sphere is a helpful model, though incorrect, for visualizing star positions.
• Stars in a constellation may be located at vastly different distances.
• The celestial sphere clarifies the Sun's motion (ecliptic), the Earth's poles, and the equator.

Circling the Sky

• We perceive objects in the sky as moving because Earth is moving.
• The local sky is the sky as seen from a particular location on Earth.
• Zero points are required to define locations in the local sky (azimuth and altitude).
• Azimuth measures direction (North, East, South, West).
• Altitude measures elevation above the horizon.
• Zenith is the point directly above (observer's head).
• The meridian is an imaginary half-circle from North through Zenith to South.

Angles

• Angles are measured using sexadecimal units.
• Measuring angular size of an object.
• Measuring angular distances between a pair of objects
• Stars and other objects in the sky appear to rise in the East and set in the West.
• This is because of Earth's rotation.
• If you could view the celestial sphere from outside, the daily motion of the stars would appear as circles.
• Two angles are required to locate any object in the local sky.

Celestial Coordinate System

• Local sky can be extended to the entire Earth's surface.
• This creates a geographical coordinate system using longitude and latitude.
• Longitude is measured from Greenwich, increasing Eastward.
• Latitude is measured from the equator, increasing Northward.

Motion of Objects in the Sky

• The path of celestial objects across the sky varies depending on their position in the celestial sphere.
• This means stars seem to move in different patterns depending on their position.
• Planets, Sun, and Moon also appear to follow these rules.

Geographic Location on Earth Calculation

• Geographic latitude can be calculated by measuring the altitude (height above the horizon) of the celestial pole.
• Geographic location and observing conditions are critical for determining the accurate position of celestial objects.

Seasons

• The Earth's axis is tilted, causing the position of the Sun in the sky to change throughout the year.
• The Earth's tilt is responsible for the seasons.
• The Sun appears to move along the ecliptic (a great circle on the celestial sphere).
• Solstices and equinoxes are specific times throughout the year.

Precession of Earth's Axis

• The Earth's axis slowly changes its orientation over a period of 26,000 years.
• The gradual change in the direction Earth's axis points in space is called precession.

Celestial Sphere

• The local sky can be extended infinitely, forming the celestial sphere.
• This sphere allows astronomers to describe the positions of objects in the sky.

The Moon

• The Moon's appearance changes throughout the month.
• The Moon orbits the Earth (its orbital period is 27.3 days).
• The Moon's rotation period is synchronized with its orbital period.

Lunar Phases

• The Moon's phases are related to how much of the Moon's surface is illuminated by the Sun.

Eclipses

• Lunar eclipses occur when the Earth is between the Sun and the Moon.
• Solar eclipses occur when the Moon is between the Sun and the Earth.
• The Moon's orbit is inclined to the ecliptic plane of the Earth.

Celestial Timekeeping

• Sidereal day is measured relative to distant stars.
• Solar day is measured relative to the Sun's movement.
• Tropical year is the time it takes for the Sun to return to the same position relative to the stars.
• Sidereal year is the time it takes for the Sun to return to the same position relative to the background (fixed) stars.

Law of Radiation

• All macroscopic objects emit radiation.
• Radiation depends on the object's temperature and its radiation.

Electromagnetic Spectrum

• All electromagnetic radiation travels in the form of waves.
• Electromagnetic radiation includes visible light, as well as radio waves, infrared, ultraviolet, x-rays, and gamma rays.
• The electromagnetic spectrum includes all wavelengths of electromagnetic radiation.

Doppler Effect

• The Doppler effect describes the change in the observed wavelength of electromagnetic radiation when an object is moving relative to the observer.

Spectroscopy

• Spectroscopy is the study of the interaction of matter with electromagnetic radiation.
• A spectroscope separates incoming radiation into its characteristic component wavelengths.

Atomic Structure

• Atoms are composed of protons, neutrons, and electrons.
• Atoms absorb and emit electromagnetic radiation at specific frequencies.

Observational Techniques

• Telescopes collect photons and concentrate them for analysis.
• There are two main types of telescopes: refracting and reflecting.
• Refracting telescopes use lenses, and reflecting telescopes use mirrors.
• Instruments like photometers and spectrometers can be used with telescopes.

Telescopes

• Large lenses cannot be constructed.
• Refraction in a refracting telescope focuses red and blue light differently, which is chromatic aberration.
• Light absorption by lenses is important for IR and UV observations, as is the absence of this effect in mirrors and lens weight.

Power of Telescopes

• Resolving power is the ability of a telescope to form separate and distinct images of objects close together.
• Angular resolution is the factor that determines this ability.

Effects of Improving Resolution

• Diffraction causes a blurry image. The angular resolution of a telescope improves and this is inversely proportional to its mirror size. Larger the mirror size, the better the image.

High Resolution Observations

• Turbulent Earth's atmosphere blurs the image and limits the resolving power of telescopes.
• Adaptive optics are used to counteract these effects.

Radio Astronomy

• Radio telescopes collect photons at radio frequencies.
• Radio telescopes are more sensitive to astronomical imperfections than visible light telescopes.

Interstellar Matter

• The interstellar medium contains dust and gas between stars in galaxies.

Structure of the Solar System

• The solar system has four major groups: inner, outer, asteroid belt, and Kuiper Belt.

Inner Planets

• Mercury, Venus, Earth, and Mars are inner planets.
• They have solid rocky surfaces.

Outer Planets

• Jupiter, Saturn, Uranus, and Neptune are outer planets.

Asteroids

• Asteroids are rocky bodies that orbit the Sun.
• The main asteroid belt is between Mars and Jupiter.

Comets

• Comets are icy bodies that orbit the Sun.
• Comets have a nucleus, a coma, and a tail.

Meteors

• Meteors are fragments of interplanetary debris that enter Earth's atmosphere and burn up.

Formation of Solar System

• The solar system formed from a collapsing cloud of gas and dust.

Earth's Magnetosphere

• Earth's magnetic field creates a protective magnetosphere that deflects charged particles from the Sun.

Earth's Tides

• The gravitational pull of the Moon and Sun on Earth causes the tides (changes in the ocean level).

Earth's Rotation

• Earth's rotation causes the apparent motion of objects in the sky.

Planets

• The eight planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune) orbit the Sun in a roughly similar plane.

Properties of the Planets

• The planets have unique properties and features.

Surface Features of Inner Planets

• Craters, volcanoes, lava plains, and other surface features are present on each inner planet based on the materials that were present at the time of formation.

Atmosphere of Inner and Outer Planets

• The atmospheres of each inner and outer planet differ widely in composition and density.

Moons of the Outer Planets

• The outer planets have numerous moons.

Summary of the Solar System

• The solar system is a relatively isolated collection of planets that orbit a central star.

Nebular Theory

• The nebular hypothesis describes the process of the formation of the Sun and planets.

Condensation Theory

• The condensation hypothesis details the condensation of gas and dust resulting in the formation of planets.