Solar System Objects and Celestial Phenomena

The solar system comprises a vast array of objects, ranging from minuscule asteroids to enormous galaxies. Understanding the scale and relationships between these objects is crucial for comprehending our place in the universe.

• Celestial objects in order of size: asteroid, moon, planet, star, solar system, galaxy, Local Group, universe
• Planets distance from the Sun in order: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
• Comets are balls of dust, gas, and ice with highly elliptical orbits around the Sun
• Earth's rotation and revolution, along with its axial tilt, cause day/night cycles and seasons

Vocabulary: NEOs (Near Earth Objects) - Objects in space such as asteroids, comets, or meteoroids that sometimes pass near Earth.

Highlight: The universe is so vast that it affects how we perceive distant objects. Telescopes are necessary to observe distant planets, while neighboring galaxies appear as blurs in the sky.

Example: A light year, the distance light travels in one year, is used to describe vast cosmic distances. For instance, the Sun is 8 light minutes away from Earth, while Proxima Centauri, the next closest star, is four light years away.

Definition: Craters are formed when NEOs enter Earth's atmosphere and impact the surface, sometimes leaving behind massive holes.

The Earth's equator divides it into the Northern and Southern hemispheres, which experience seasons differently due to the planet's axial tilt as it orbits the Sun. This 23.5-degree tilt causes one hemisphere to receive more direct sunlight at different times of the year, resulting in the four seasons.

Highlight: Key dates for seasonal changes include:

• March 21/22: Spring equinox (North), Autumn equinox (South)
• June 21/22: Summer solstice (North), Winter solstice (South)
• September 22/23: Autumn equinox (North), Spring equinox (South)
• December 21/22: Winter solstice (North), Summer solstice (South)