Definition: A dim light seen in the sky that appears directly opposite the sun, likely caused by sunlight reflecting off tiny particles in space.

Example: On a clear night, we could see the gegenschein shining softly in the sky opposite the sun.

Definition: Describing a viewpoint or model that considers the Earth as the center of the universe or a system.

Example: In a geocentric model, the Earth is placed at the center of the solar system, with all other celestial bodies orbiting around it.

Definition: In a way that relates to the Earth being at the center of the universe, especially in historical or astronomical contexts.

Example: The ancient astronomers viewed the stars and planets geocentrically, believing that everything revolved around the Earth.

Definition: Relating to a satellite that orbits the Earth at the same rate that the Earth rotates, allowing it to stay in a fixed position above a specific point on the Earth's surface.

Example: The communication satellite is geostationary, providing constant coverage to the same area.

Definition: Relating to an orbit that matches the Earth's rotation, allowing a satellite to stay in the same position relative to the Earth's surface.

Example: The communication satellite is geosynchronous, so it remains above the same point on Earth.

Definition: Describing a shape that is rounded or bulging, especially when referring to the moon or a planet that is more than half illuminated but not fully.

Example: The moon was gibbous, casting a soft light over the landscape.

Definition: Related to the force that pulls objects toward each other, especially the force that keeps us on the ground.

Example: The gravitational pull of the Earth keeps the moon in orbit.

Definition: In a way that relates to the force of gravity.

Example: The planets move gravitationally around the sun due to its massive pull.

Definition: A theoretical particle that is thought to be a fermion connected to the graviton in the context of supersymmetry and supergravity theories.

Example: Scientists are researching the properties of the gravitino to understand its role in the universe.

Definition: A theoretical particle that is believed to carry the force of gravity, having no electric charge and no mass.

Example: Scientists are researching the properties of the graviton to better understand gravity at the quantum level.