Earth’s axis tilt is the angle at which the planet spins compared to its orbit around the Sun. This tilt causes different parts of Earth to receive varying amounts of sunlight during the year, creating the seasons — spring, summer, fall, and winter.
A solstice occurs when one hemisphere is tilted most toward or away from the Sun, resulting in the longest and shortest days of the year. An equinox happens when day and night are nearly equal in length worldwide.
Tides are the regular rise and fall of ocean water, mainly caused by the Moon’s gravity and partly by the Sun’s gravity.
Rotation is the spinning of an object on its axis. For example, Earth rotates once every 24 hours, which causes day and night.
Revolution is the movement of one object around another object. Earth revolves around the Sun once every 365 days, which gives us one year.
The heliocentric model is the idea that the Sun is at the center of the solar system and the planets revolve around it. This model was supported by scientists like Copernicus and Galileo.
The geocentric model is the earlier belief that Earth is at the center of the universe and that the Sun, Moon, and planets move around Earth.
Terrestrial planets are rocky planets with hard surfaces and include Mercury, Venus, Earth, and Mars.
Gas giants are much larger planets made mostly of gases like hydrogen and helium; these include Jupiter, Saturn, Uranus, and Neptune.
Mercury, the smallest planet and the closest to the Sun, which orbits the Sun faster than any other planet. Venus is the second planet from the Sun and is the brightest planet in the sky.
Finally, an atmosphere is defined as the layers of gases that surround Earth or other planets.
The universe includes all space and everything in it—every bit of matter and energy that exists. Within the universe are galaxies, which are massive collections of billions of stars, along with dust and gas, all held together by gravity.
Our galaxy contains our solar system, which includes the Sun and all the planets and other objects that orbit around it.
A planet is a large, round object that travels around a star in an elliptical orbit. Earth is a planet that orbits the Sun. The Big Bang Theory, which states that all matter and energy in the universe were once compressed into an extremely small point called a singularity.
This singularity expanded rapidly, beginning the formation of the universe as we know it today.
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