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large cloud of gas and dust in space. It’s often the place where new stars are born.
large cloud of gas and dust in space. It’s often the place where new stars are born.
measures how stretched out an orbit is. A perfect circle has an eccentricity of 0; more stretched orbits have higher values (up to just under 1).
Eccentricity
spinning of a planet on its axis. Earth’s rotation takes about 24 hours and causes day and night.
Rotation
the process that powers the Sun. It happens when hydrogen atoms are smashed together under extreme pressure and heat to form helium, releasing a huge amount of energy.
nuclear fusion
Tilt
Earth’s tilt is the 23.5° angle of its axis. This tilt, combined with revolution, causes the changing seasons.
imaginary line through a planet from the North Pole to the South Pole. Earth spins around this line.
Axis
force that pulls objects toward each other. It keeps the planets in orbit around the Sun and causes things to fall to the ground on Earth.
Gravity
says that a planet moves faster when it is closer to the Sun and slower when it is farther from the Sun — but it always sweeps out equal areas in equal times. ( Law of Equal Areas)Planets move faster near the Sun and slower farther away, but they always cover equal areas in equal time.
Kepler's second law
gas giants (Jovian Planets)
also called Jovian planets, are large planets made mostly of gases like hydrogen and helium. In our solar system, these are Jupiter, Saturn, Uranus, and Neptune.
is the time it takes for an object to complete one full orbit
orbital period
Revolution
movement of one object around another. Earth’s revolution around the Sun takes about 365 days and causes the seasons.
Kepler's first law
says that planets orbit the Sun in an elliptical (oval-shaped) path, not in perfect circles. ( Law of Ellipses)
Neap Tide
weaker tide with less difference between high and low tides. It happens when the Moon and Sun form a right angle with Earth (during first and third quarters).
very high high tide and very low low tide. It happens when the Earth, Moon, and Sun are in a straight line (during full and new moons).
Spring Tide
small, rocky planets close to the Sun. In our solar system, these are Mercury, Venus, Earth, and Mars.
terrestrial planets
Planets that are farther from the Sun move more slowly and take more time to go around the Sun than planets that are closer.
Kepler's third law
the path one object in space takes around another
Orbit
is a small piece of rock or metal floating in space. If it enters Earth’s atmosphere and burns up, it becomes a meteor (a "shooting star")
Meteoroid
Solar Nebular Theory
explains how our solar system formed. It says that the Sun and planets formed from a spinning cloud of gas and dust (a nebula) about 4.6 billion years ago
includes all types of light energy, from radio waves (longest) to gamma rays (shortest). Visible light is just a small part of this spectrum.
Electromagnetic Spectrum