Solar Radiation and Energy

Solar Radiation

• Solar radiation refers to electromagnetic waves, including light, that travel from the sun to Earth
• There are three main types of solar radiation: visible, infrared, and ultraviolet wavelengths
  • Visible light is divided into subcategories: red, orange, yellow, green, blue, indigo, and violet
  • Infrared light has a lower frequency than visible light and a wavelength between 2.5 μm and 750 nm
  • Ultraviolet light has a higher frequency than visible light and a wavelength between 1-400 nm

Effects of Solar Radiation

• Solar radiation affects the Earth's climate, weather, and seasons
• Energy from the sun is trapped by greenhouse gases, causing the greenhouse effect and warming the Earth
• The tilt of the Earth's axis causes different parts of the planet to receive varying amounts of sunlight, resulting in different seasons
• The total amount of solar energy the Earth receives remains constant, despite seasonal changes

Wind and Water Cycle

• The sun's energy heats the Earth unequally, causing areas of low and high pressure
• Wind is created when air moves from high to low pressure areas
• The transfer of light energy from the sun into heat energy drives the water cycle
• Water evaporates from the surface, condenses into clouds, and returns to the surface as precipitation

Astronomical Units and Telescopes

• An astronomical unit (AU) is the average orbital distance of the Earth from the Sun, approximately 93 million miles
• Astronomical distances can be measured in AUs, light-years, or parsecs
• Telescopes are used to study the universe, and come in different types:
  • Refracting telescopes use lenses to produce images
  • Reflecting telescopes use mirrors to produce images
  • Compound telescopes use a combination of lenses and mirrors
  • Radio, X-ray, and gamma-ray telescopes detect electromagnetic radiation

The Solar System and Universe

• The Solar System consists of the Sun, planets, moons, asteroids, dwarf planets, Kuiper belt objects, meteoroids, comets, and interplanetary dust
• A galaxy is a collection of gas, dust, and stars held together by gravity
• The Universe is all of space, matter, energy, time, and its contents
• The Universe is vast, with hundreds of billions of galaxies
• Galaxies come in different shapes, such as spiral, elliptical, or irregular

Stars and Their Properties

• Stars are formed in stellar nebulas, or large gas clouds made from hydrogen
• The life cycle of a star depends on its mass
  • Low-mass stars become red giants and then planetary nebulas
  • High-mass stars become red supergiants and then undergo a supernova
• Luminosity is the total energy a star radiates in one second
• Temperature and luminosity are used to categorize stars into spectral classes
• The Hertzsprung-Russell diagram plots a star's luminosity vs. surface temperature

Solar Radiation

• Solar radiation refers to electromagnetic waves, including light, that travel from the sun to Earth
• There are three main types of solar radiation: visible, infrared, and ultraviolet wavelengths
  • Visible light is divided into subcategories: red, orange, yellow, green, blue, indigo, and violet
  • Infrared light has a lower frequency than visible light and a wavelength between 2.5 μm and 750 nm
  • Ultraviolet light has a higher frequency than visible light and a wavelength between 1-400 nm

Effects of Solar Radiation

• Solar radiation affects the Earth's climate, weather, and seasons
• Energy from the sun is trapped by greenhouse gases, causing the greenhouse effect and warming the Earth
• The tilt of the Earth's axis causes different parts of the planet to receive varying amounts of sunlight, resulting in different seasons
• The total amount of solar energy the Earth receives remains constant, despite seasonal changes

Wind and Water Cycle

• The sun's energy heats the Earth unequally, causing areas of low and high pressure
• Wind is created when air moves from high to low pressure areas
• The transfer of light energy from the sun into heat energy drives the water cycle
• Water evaporates from the surface, condenses into clouds, and returns to the surface as precipitation

Astronomical Units and Telescopes

• An astronomical unit (AU) is the average orbital distance of the Earth from the Sun, approximately 93 million miles
• Astronomical distances can be measured in AUs, light-years, or parsecs
• Telescopes are used to study the universe, and come in different types:
  • Refracting telescopes use lenses to produce images
  • Reflecting telescopes use mirrors to produce images
  • Compound telescopes use a combination of lenses and mirrors
  • Radio, X-ray, and gamma-ray telescopes detect electromagnetic radiation

The Solar System and Universe

• The Solar System consists of the Sun, planets, moons, asteroids, dwarf planets, Kuiper belt objects, meteoroids, comets, and interplanetary dust
• A galaxy is a collection of gas, dust, and stars held together by gravity
• The Universe is all of space, matter, energy, time, and its contents
• The Universe is vast, with hundreds of billions of galaxies
• Galaxies come in different shapes, such as spiral, elliptical, or irregular

Stars and Their Properties

• Stars are formed in stellar nebulas, or large gas clouds made from hydrogen
• The life cycle of a star depends on its mass
  • Low-mass stars become red giants and then planetary nebulas
  • High-mass stars become red supergiants and then undergo a supernova
• Luminosity is the total energy a star radiates in one second
• Temperature and luminosity are used to categorize stars into spectral classes
• The Hertzsprung-Russell diagram plots a star's luminosity vs. surface temperature