Topic 3-Earth and Universe - Vocabulary - Earth and Universe terms

Sep 28, 2026

Topic 3 - Earth and Universe vocabulary and overview explains core concepts in astronomy and planetary science. It defines key terms such as asteroid, comet, galaxy, star, celestial object, solar system, moon, rotation and revolution, plus orbital descriptors like ellipse, focus, foci and eccentricity. The document also summarizes the origin and age of the universe using Big Bang evidence from red shift, and outlines how stars produce energy through nuclear fusion, along with major stellar life stages. Solar system sections cover planetary types, moons, asteroids, meteoroids and comets, followed by solar-nebula evolution and planet motions.

LanguageEnglish

CategoryExam

FormatPDF

Pages14

Reading Time35 min

AccessFree to download

Topic 3 - Earth and Universe

Vocabulary

Overview of Topic

Origin and Age of the Universe

Stars including our Sun

Solar System

Evolution of the Solar System

Characteristics of planets

Planet Motions

Topic 3-Earth and Universe Vocabulary Asteroid – solid rocky objects orbiting the sun that are large and irregularly shaped. Big Bang theory – Universe started as a big explosion containing all matter 15 – 17 billion years ago. Celestial object – objects outside of the Earth’s atmosphere such as the moon, stars, sun, planets, etc … Comet – a low density celestial object that orbits the sun made up of ices that vaporizes Doppler Effect – the apparent change in wavelength as an object moves in relation to the observer. Eccentricity – the degree of ovalness of an ellipse, either flat or round with a value between 0.000 to 1.000. Ellipse – a closed circle around an object(s) called foci. Describes orbits of celestial objects with values between 0.000 to 1.000. Focus – plural foci. The two points real and imaginary, in an orbit that a celestial object orbits orbit either a star or planet. Galaxy – a large grouping of millions or more stars held together by gravitational attraction, such as our galaxy the Milky Way. Jovian planet – the planets that are furthest from the sun; large, gaseous and low densities. Luminosity – the measure brightness of a star compared to the sun. Moon – the natural satellite that orbits the Earth. Nuclear fusion – the smashing of atoms in a star that makes their light and energy. Red shift – the movement of the wavelength to the red part of the spectrum, used to determine object moving away from Earth, used to determine object in universe are moving away from each other. Revolution – an objects movement in an orbit around another larger object, such as the Earth – Moon orbit or the Earth – Sun orbit. Rotation – the spinning on abject on its axis. Solar system – a group of objects that orbit a star under the influence of gravity. Earth is part of the Solar System. Star – a large ball of gas producing tremendous amounts of energy, the sun. Terrestrial planet – rocky planets closest to the sun; small and high density. Earth is a terrestrial planet. Universe – everything that exists in totality. We are part of the universe. Overview of Topic I. Origin and Age of the Universe - Estimated to be 12-14 billion years old. a. Evidence for the Big Bang i. Determined from red shift in the spectra 1. Red shift indicates objects are moving away from the observer. 2. Blue shifted means moving towards an observer 3. Spectral lines in laboratory spectrum will either move to the red (away) or the blue (towards) 4. Majority of objects are red shift indicating expansion of universe. II. Stars including our Sun - Many sizes, many ages and many types are found in you galaxy, the Milky Way and other galaxies in the universe. a. Energy production i. Nuclear fusion combines hydrogen into helium. ii. Energy produced is in the form of electromagnetic radiation 1. Page 14 ESRT – Electromagnetic Spectrum b. Characteristics of stars i. Based on Luminosity 1. Bigger is more luminous 2. Hotter is more luminous c. Star types i. Page 15 ESRT – Characteristics of Stars 1. Horizontal axis a. Surface temperature - Increases left to right b. Color 2. Vertical axis a. Luminosity - Increase towards top - Largest stars at top Smallest stars bottom ii. Main sequence 90% of all stars located here - Our Sun - Fusing hydrogen - Can be small red dwarf to large blue giants - Blue is hot, burning fuel fast, short lived - Red is cool, burning fuel slow, long lived iii. Giants - Late stage star – dying - Main sequence star that is no longer fusing hydrogen - Our sun will follow the path - Become white dwarfs iv. Super giants - Late stage star – dying massive star - Massive main sequence stars that is no longer fusing hydrogen. - Become black holes or neutron stars v. White dwarfs - Very small - Remains of a star core. - Our sun will become a white dwarf d. Star origin and evolution i. Nebula - Space dust that forms

FAQs

How does red shift provide evidence for the Big Bang and an expanding universe?

Red shift indicates objects are moving away from the observer. When most distant objects show red shift, it supports the idea that the universe is expanding.

What process powers a star’s energy production?

Nuclear fusion combines hydrogen into helium. The released energy appears as electromagnetic radiation.

What is the difference between planetary rotation and revolution?

Rotation is the spinning of a planet on its axis. Revolution is the orbit of a planet around a larger object, such as the Earth-Moon or Earth-Sun path.

Sep 28, 2026

Uploaded by Nguyễn Văn Học