🌌 Earth & Space Science - Space Unit Study Guide 🌌

🚀 The Universe & The Big Bang

• Big Bang Theory – The theory that the universe began as a single point and has been expanding ever since.

• Redshift – When light from galaxies shifts toward the red end of the spectrum, showing they are moving away (evidence for expansion).

• Blueshift – When light shifts toward blue, showing an object is moving toward us.

• Cosmic Microwave Background (CMB) – Faint radiation left over from the Big Bang, found everywhere in the universe.

🌟 Light & Spectra

• Electromagnetic Spectrum – The full range of light waves, including visible light, infrared, ultraviolet, X-rays, etc.

• Absorption Spectrum – A spectrum with dark lines where certain wavelengths are absorbed by elements in a star’s atmosphere.

• Emission Spectrum – A spectrum with bright lines, showing specific wavelengths emitted by a gas.

• Continuous Spectrum – A complete rainbow of colors, created by hot, dense objects.

• Doppler Effect – The change in wavelength due to motion (used to explain redshift and blueshift).

🪐 Kepler’s Laws of Planetary Motion

1. First Law (Elliptical Orbits) – Planets move in ellipses, not perfect circles, with the Sun at one focus.

2. Second Law (Equal Areas Law) – Planets move faster when they are closer to the Sun and slower when farther away.

3. Third Law (Orbital Period Law) – The farther a planet is from the Sun, the longer its orbit takes.

🌞 The Life Cycle of Stars

• Nebula – A cloud of gas and dust where stars are born.

• Protostar – A forming star before nuclear fusion begins.

• Main Sequence – The stable phase where stars fuse hydrogen into helium (the Sun is here).

• Red Giant / Supergiant – A star that has run out of hydrogen and starts fusing heavier elements.

• Supernova – A massive explosion at the end of a large star’s life.

• White Dwarf – A small, hot, but dim core of a dead low-mass star.

• Neutron Star – A dense, collapsed core left after a supernova (made mostly of neutrons).

• Black Hole – A region of space with gravity so strong that nothing, not even light, can escape.

🌌 H-R Diagram (Hertzsprung-Russell Diagram)

• A graph that plots stars based on temperature and luminosity (brightness).

• Main Sequence – Stars in the stable phase (includes the Sun).

• Red Giants/Supergiants – Large, bright, but cooler stars.

• White Dwarfs – Small, hot, but dim remnants of dead stars.

🌠 Constellations & Motion

• Constellations – Patterns of stars in the sky that appear to move due to Earth’s rotation and orbit.

• Earth’s Rotation – Causes daily movement of stars (makes them appear to rise and set).

• Earth’s Revolution – Causes seasonal changes in visible constellations.