Astronomy

  • Earth: The third planet from the Sun, home to all known life, with a diameter of about 12,742 km and a surface composed of land and water.

  • East: One of the four cardinal directions; it is the direction toward which the Earth rotates and where the Sun rises.

  • Kepler: Refers to Johannes Kepler, a German astronomer who discovered the laws of planetary motion. Also the name of a space telescope launched by NASA to discover Earth-like planets.

  • Kuiper Belt: A region of the Solar System beyond Neptune, filled with small icy bodies and dwarf planets like Pluto.

  • Uranus: The seventh planet from the Sun, known for its tilted axis, icy composition, and faint rings.

  • Van Allen Protective Belts: Zones of charged particles trapped by Earth’s magnetic field that protect the planet from harmful solar radiation.

  • Eratosthenes: An ancient Greek mathematician and geographer who calculated the circumference of the Earth with remarkable accuracy.

  • Light Year: A unit of distance that measures how far light travels in one year (about 9.46 trillion kilometers).

  • Venus: The second planet from the Sun, similar in size to Earth but with a thick atmosphere of carbon dioxide and sulfuric acid clouds.

  • 4.6: Refers to the approximate age of the Solar System, which is about 4.6 billion years old.

  • Europa (Galileo): Europa is one of Jupiter’s largest moons, known for its icy surface and the possibility of an ocean beneath. Galileo refers to the Galileo spacecraft that studied Jupiter and its moons.

  • Mars: The fourth planet from the Sun, known as the Red Planet due to iron oxide (rust) on its surface, and a potential target for human exploration.

  • Zenith: The point in the sky directly above an observer.

  • 8: Refers to the number of planets in our Solar System.

  • Mercury: The closest planet to the Sun, known for its extreme temperatures and short orbital period (88 days).

  • 23.5: The axial tilt of Earth, responsible for the changing seasons.

  • Geocentric: An ancient model of the universe that places Earth at the center, with the Sun and planets revolving around it.

  • Methane: A colorless, odorless gas (CH₄) found in the atmospheres of planets like Uranus and Neptune, and in the moons Titan and Triton.

  • 88: The number of days it takes for Mercury to complete one orbit around the Sun.

  • Heliocentric: The model of the solar system that places the Sun at the center, with planets orbiting around it (first proposed by Copernicus).

  • Milky Way: The galaxy that contains our Solar System, a barred spiral galaxy that is home to billions of stars.

  • Apollo: Refers to NASA’s Apollo program, which successfully sent humans to the Moon between 1969 and 1972.

  • Hydrogen: The lightest and most abundant element in the universe, making up about 75% of all normal matter, and a key component in stars.

  • Moon: Earth’s natural satellite, which orbits the planet every 27.3 days.

  • Artemis: NASA’s current program aimed at returning humans to the Moon and eventually sending astronauts to Mars.

  • Impact Craters: Circular depressions on planets, moons, and asteroids caused by collisions with meteoroids or comets.

  • Neptune: The eighth planet from the Sun, known for its deep blue color, strong winds, and large moon, Triton.

  • Astronomical Unit (AU): A unit of distance equal to the average distance between Earth and the Sun, about 149.6 million kilometers.

  • Inertia: A property of matter that resists changes in motion; in space, objects will keep moving at a constant speed and direction unless acted upon by an outside force.

  • Newton: Refers to Sir Isaac Newton, who formulated the laws of motion and universal gravitation. Also connected with the Oort Cloud, a distant region of icy bodies surrounding the Solar System.

  • Brahe: Tycho Brahe, a Danish astronomer known for his accurate and comprehensive astronomical observations, which laid the groundwork for Kepler's laws of planetary motion.

  • Dwarf Planet: A celestial body that orbits the Sun and is spherical in shape but has not cleared its orbit of other debris (e.g., Pluto).

  • Io: One of Jupiter’s largest moons, known for its intense volcanic activity.

  • Jupiter: The fifth and largest planet in the Solar System, famous for its Great Red Spot, a giant storm, and its many moons.

  • Saturn: The sixth planet from the Sun, well known for its prominent ring system made of ice and rock particles