Untitled Flashcards Set

Scientific Notation

A method of expressing numbers as a product of a coefficient and a power of 10.

Hypothesis

A testable explanation of an observation.

Theory

A well-developed idea or group of ideas that agrees with known physical laws and makes testable predictions.

Principles

General ideas or guidelines about the universe that often guide the construction of new theories.

Cosmological Principle

The assumption that the universe is homogeneous and isotropic on a large scale.

Occam's Razor

The principle that suggests that the simplest explanation is usually the correct one.

Spring Tide

Tides that occur when the moon is high in the sky, producing higher high tides and lower low tides.

Neap Tide

Tides that occur when the moon is low in the sky, leading to lower high tides and higher low tides.

Solar Eclipse

An event where the moon blocks the light from the sun, casting a shadow on the Earth.

Lunar Eclipse

An event where the Earth's shadow blocks the sun's light from reaching the moon.

Geocentric Model

The ancient model of the universe where the Earth is at the center.

Heliocentric Model

The model of the universe where the Sun is at the center, and the planets, including Earth, orbit around it.

Newton's 1st Law

An object will not change its motion unless a force acts on it.

Newton's 2nd Law

The force on an object is equal to its mass times its acceleration (F=ma).

Orbit

The curved path of an object around a star, planet, or moon.

Weightlessness

The condition experienced in free fall where the force of gravity is not felt.

Photon

A discrete packet of light energy.

Absorption Spectrum

The spectrum produced when an atom absorbs light, showing dark lines over a rainbow.

Emission Spectrum

The spectrum produced when an atom emits light, showing bright lines on a dark background.

Doppler Effect

The change in frequency of a wave in relation to an observer moving relative to the source.

Reflection Telescope

A telescope that uses mirrors to gather and focus light.

Refraction Telescope

A telescope that uses lenses to bend light as it passes through.

Kepler's Laws

Three laws that describe the motion of planets around the sun: 1) planets move in elliptical orbits, 2) a line segment joining a planet and the sun sweeps out equal areas during equal intervals of time, 3) the square of the period of a planet is proportional to the cube of the semi-major axis of its orbit.

Luminosity

The total amount of energy emitted by a star or other celestial body per unit time.

Redshift

The phenomenon where the wavelength of light from an object is increased (shifted to the red end of the spectrum) as the object moves away from an observer, indicating the universe is expanding.

Black Hole

A region in space where the gravitational pull is so strong that nothing, not even light, can escape from it.

Event Horizon

The boundary around a black hole beyond which no light or other radiation can escape.

Gravity

The force that attracts two bodies towards each other, proportional to their masses and inversely proportional to the square of the distance between them.

Supernova

A powerful and luminous explosion of a star that occurs at the end of its life cycle.

Neutron Star

A compact celestial object composed almost entirely of neutrons, formed by the gravitational collapse of a massive star after a supernova.

Planetary Nebula

A ring-shaped nebula formed by the expansion of gas from a red giant star at the end of its life.

Red Giant

A late phase in the life cycle of a star, characterized by a large size and a reddish color due to cooler surface temperatures