Earth and Space

• The stratosphere is the second layer of the Earth's atmosphere, above the troposphere, and contains the ozone layer.
• Mercury is closest to the Sun and has no atmosphere or water on its surface.
• The continuous process of one tectonic plate moving under another caused volcanic activity and mountain building at the surface of the Earth.
• Our solar system consists of eight planets, five dwarf planets, asteroids, comets, moons, and other objects that orbit around the sun.
• The increase in density caused the materials to settle towards the center and form the Earth's core, with the lighter elements gathering at the surface to form the Earth's crust.
• The Earth initially solidified from a massive cloud of gas and dust about 4.5 billion years ago.
• The sun is the center of our solar system.
• The inner core is the solid, innermost layer of the Earth, composed mostly of iron and nickel.
• The Earth's crust is the outermost layer of the Earth and is composed of solid rock.
• The thermosphere is the fourth layer of the Earth's atmosphere, above the mesosphere, where temperatures increase with altitude due to solar radiation.
• The mesosphere is the third layer of the Earth's atmosphere, between the stratosphere and thermosphere, where temperatures decrease with altitude.
• Exoplanets are planets that orbit stars outside our own solar system.
• Venus is similar in size to Earth but has an extremely thick atmosphere that traps heat and makes it hotter than any other planet.
• Jupiter is larger than all planets combined and has many moons, including Ganymede which is bigger than Mercury.
• Plate tectonics refers to the movement of large plates that make up the lithosphere (the solid outer part of the earth).
• Mars is smaller than Earth and has a thin atmosphere with little oxygen.
• Convection currents are created by heat from the core of the Earth causing hot rock to rise and cooler rock to sink.
• Asteroids are small rocky bodies that orbit between Mars and Jupiter.
• The inner core is solid iron and nickel, while the outer core is liquid iron and nickel.
• The mantle is made up of rocky material and makes up most of the volume of the Earth.
• Comets have an icy nucleus surrounded by dust and gas.
• Sea-floor spreading occurs when new crust forms along mid-ocean ridges as magma rises through fractures in the ocean floor.
• The Earth's interior can be divided into three main layers based on their composition and physical properties: the inner core, outer core, and mantle.
• The Earth's magnetic field protects us from dangerous charged particles coming from space.
• The lithosphere is composed of rigid plates that float on top of the asthenosphere.
• Moons are natural satellites that orbit planets.
• The outer core is the liquid layer surrounding the inner core, also made up mainly of molten iron and nickel.
• The Earth's rotation causes day and night.
• Comets have an icy nucleus surrounded by a gaseous envelope called a coma.
• The mantle is the thick layer between the core and the crust, consisting primarily of silicate rocks.
• The atmosphere is the gaseous envelope surrounding the Earth, consisting primarily of nitrogen and oxygen.
• Asteroids are small celestial bodies made up mainly of rocks and metals, found primarily in the asteroid belt between Mars and Jupiter.
• Jupiter is larger than all the terrestrial planets combined and has many moons, including four large ones known as the Galilean Moons.
• Comets are celestial objects consisting of ice, dust, and gas, which can be seen as bright streaks in the sky when they approach the Sun.
• Uranus is tilted on its side, causing it to appear almost stationary in the sky over long periods of time.
• Saturn's rings consist mostly of water ice particles that range from tiny grains to boulder-sized chunks.