Take The Astronomy Vocab Practice Questions!

Gravity is the force that causes the moon to fall toward the Earth and changes its straight-line path into a curved orbit. Gravity is the attractive force between two objects with mass, and it is responsible for keeping celestial bodies, like the moon, in orbit around larger objects, like the Earth. This force pulls the moon towards the Earth, constantly changing its direction and causing it to move in a curved path rather than a straight line.

A small body of ice, rock, and cosmic dust loosely packed together is called a comet. Comets are celestial objects that orbit the sun in elongated elliptical paths. As they approach the sun, the heat causes the ice in the comet to vaporize, creating a glowing coma (a cloud of gas and dust) around the nucleus. The coma often forms a tail that points away from the sun due to solar wind. Comets are believed to be remnants from the early formation of the solar system and can provide valuable information about its history.

A lunar eclipse occurs when Earth comes between the sun and the moon and the shadow of Earth falls on the moon. During this phenomenon, the moon appears to darken as it enters the Earth's shadow, creating a reddish or coppery hue. This happens because the Earth blocks the sunlight from reaching the moon's surface directly. Lunar eclipses can only occur during a full moon when the sun, Earth, and moon are aligned in a straight line.

A galaxy is a collection of stars, dust, and gas bound together by gravity. Galaxies are vast systems that can contain billions or even trillions of stars. They come in different shapes and sizes, ranging from spiral galaxies with arms and a central bulge, to elliptical galaxies that are more spherical in shape. The gravitational force within a galaxy keeps all its components together, allowing them to orbit around a common center. Galaxies are the building blocks of the universe and play a crucial role in shaping its structure and evolution.

A solar eclipse occurs when the moon aligns itself between the Earth and the sun, causing the moon's shadow to fall on a portion of the Earth. During this alignment, the moon blocks the sunlight from reaching the Earth, resulting in a temporary darkening of the sky in the affected area.

A complete trip along an orbit is called a revolution. This term is commonly used in astronomy to describe the movement of celestial bodies around a central object. In the case of planets, one revolution refers to the complete journey around the sun. Similarly, for satellites or spacecraft, one revolution signifies a complete orbit around a planet or celestial body. The concept of revolution helps in understanding the periodicity and cyclical nature of celestial motions.

The Ptolemaic theory, also known as geocentric theory, was developed by Ptolemy and states that the Earth is at the center of the universe. According to this theory, the other planets and the sun revolve around the Earth.

Venus spins in a clockwise direction, which is opposite to the usual counterclockwise rotation of most planets. This opposite rotation is known as retrograde rotation.

The Big Bang Theory is a scientific explanation that states that the universe originated from a massive explosion approximately 13.7 billion years ago. This theory is supported by various pieces of evidence, such as the observation of the cosmic microwave background radiation and the expansion of the universe. It suggests that all matter, energy, and space were created during this event, leading to the formation and evolution of galaxies, stars, and planets over time.

A nebula is a region in space where stars are born or where stars explode at the end of their lives. It is also classified as a large cloud of gas and dust in interstellar space. Nebulas are often illuminated by nearby stars or by the energy released during the star formation or explosion processes. They come in various shapes and sizes, and their colors are determined by the types of gases and elements present within them. Nebulas play a crucial role in the formation and evolution of galaxies.

A meteor is the bright streak of light caused by a meteoroid or comet dust burning up in the atmosphere.

The correct answer is "heliocentric." The Copernican theory, also known as the heliocentric theory, proposes that the sun is at the center of the universe, and all the planets revolve around it. This theory challenged the previously accepted geocentric model, which stated that the Earth was the center of the universe. Copernicus' heliocentric theory revolutionized our understanding of the solar system and laid the foundation for modern astronomy.

Small, rocky bodies that revolve around the sun are commonly known as asteroids. These objects are typically found in the asteroid belt, a region located between the orbits of Mars and Jupiter. Asteroids vary in size, with some being as small as a pebble and others reaching several hundred kilometers in diameter. They are remnants from the early solar system and provide valuable insights into the formation and evolution of our solar system.

A meteoroid that enters Earth's atmosphere and strikes the ground is called a meteorite.

The term "prograde rotation" refers to the direction in which Earth appears to spin when viewed from above its North Pole, which is counterclockwise. This means that Earth rotates in the same direction as it orbits the sun.