Space physics

Topics

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Sample objectives

What this unit covers

• The Earth: Understand that the Earth is a planet that rotates on its tilted axis approximately every 24 hours, and use this knowledge to explain the observed daily movement of the Sun and the cycle of day and night.
• The Earth: Recognize that the Earth completes an orbit around the Sun roughly every 365 days, and apply this understanding to explain the cyclical nature of the seasons.
• The Solar System: Explain that the Solar System consists of: (a) one star, the Sun, (b) eight named planets in their order from the Sun, (c) minor planets like dwarf planets such as Pluto and asteroids that orbit the Sun, (d) moons that orbit the planets, and (e) smaller bodies like comets and natural satellites.
• The Solar System: Understand that the four planets closest to the Sun are small and rocky, while the four farthest are large and gaseous, and explain this distinction using the accretion model of Solar System formation, which includes: (a) the role of gravity, (b) the variety of elements in interstellar gas and dust clouds, and (c) the rotation of material leading to the formation of an accretion disc.
• The Sun as a star: Understand that the Sun is a medium-sized star primarily made up of hydrogen and helium, emitting most of its energy in the infrared, visible light, and ultraviolet parts of the electromagnetic spectrum.
• The Sun as a star: Recognize that stars generate energy through nuclear reactions, specifically the fusion of hydrogen into helium in stable stars.
• Stars: Identify that galaxies consist of billions of stars, that the Sun is a star located in the Milky Way galaxy, that other stars in the Milky Way are significantly farther from Earth than the Sun, and that astronomical distances are measured in light-years, with one light-year being the distance light travels in a year in a vacuum.
• Stars: Recognize that one light-year is equivalent to 9.5 x 10^15 meters.
• The Universe: Understand that the Milky Way is one of countless galaxies that constitute the Universe, with a diameter of about 100,000 light-years.
• The Universe: Explain redshift as the increase in the wavelength of electromagnetic radiation from stars and galaxies that are moving away from us.