Astronomy Chapter Basics

Galaxies are categorized into elliptical, spiral, spiral barred, and irregular types.

A galaxy with an elliptical shape.

A galaxy with a spiral structure.

A spiral galaxy with a bar-shaped structure through the center.

Our galaxy; a spiral barred galaxy with a central bulge and spiral arms.

The Sun is at the center of our solar system.

Asteroids have irregular and flattened shapes.

Eight main planets and smaller bodies orbit the sun.

Comets are icy masses.

Solar system formed from a nebula.

The initial state and origin of the universe.

The ongoing increase in the size of the universe.

Links galaxy distance to its speed away from us.

Rapid expansion immediately after Big Bang.

Estimated using Hubble's Law

Stars begin in nebulas, clouds of gas and dust. Gravity pulls these materials together creating a protostellar object, which eventually becomes a star.

A stage in a star's life, where it fuses hydrogen into helium in its core to generate energy. It is a stable stage in a star's life.

A star in a later phase of life when it runs out of hydrogen fuel in its core. This causes the outer layers to expand and cool, creating a large, red star.

A massive explosion of a dying star. This happens in very massive stars at the ends of their life.

The dense core that remains after a red giant sheds its outer layers. It slowly cools down.

The Sun's core is the innermost region where nuclear fusion, the process that generates the Sun's energy, takes place.

Energy is transported outward through the Radiative Zone primarily by radiation, where photons travel through the dense plasma.

The Convective Zone is where energy is transported outward by convection, similar to how hot air rises in a pot of boiling water.

Prominences are large, bright, luminous structures extending outward from the Sun's surface, often seen as loops or arches.

The photosphere is the visible surface of the Sun, where granules of gas rising from the convective zone are visible.