earth and space

• big bang theory: 14 billion years ago, universe was inside a hot and dense ball that exploded, time space and matter were created. after 1 billion years stars and galaxies were formed
• evidence for big bang: cosmic background radiation was discovered and universe is continuously expanding
• neil armstrong was the first human on the moon
• developments from space exploration: medicine (heart monitors), industry (cordless tools), materials (fireproof clothing)
• uses of satellites: gps and weather forecasting
• hazards of space exploration: muscles shrink due to lack of gravity and heart doesn’t have to work as hard thus getting weaker
• accidents in space: apollo 1 where all 3 astronauts were killed in a fire in the cockpit during prelaunch tests
• life cycle of a star: formation, stable period, red giant and lastly white dwarf
• terrestrial planets orbit closest to the sun (mercury, venus, earth, mars)
• jovian planets are very big and have rings (jupiter, saturn, uranus, neptune)
• pluto is a dwarf/planetoid
• we only see one side of the moon since it revolves earth and rotates on its own axis at the same time
• if the part of earth is tilted towards the sun then it’s summer for that part of the world
• lunar eclipse is when earth is between moon and sun and solar eclipse is when moon is in the middle of sun and earth
• star: a large ball of gas that gives off light and heat
• galaxy: a collection of millions of stars
• satellite: any object that orbits a larger object or planet
• asteroid: a small rocky object that orbits a star
• comet: a small object composed of frozen gases, ice, rock and dust that can glow and produces a tail