Big Bang Theory and Galactic Structures

These flashcards cover key vocabulary and concepts from the lecture on the Big Bang Theory, galaxies, star clusters, exoplanets, and their properties.

Big Bang Theory

A model explaining the origin of the universe, stating it began 13.7 billion years ago from a hot, dense state.

Galaxies

Large groupings of stars, gas/dust, and planets held together by gravity, potentially numbering in the billions.

Redshift

The phenomenon where light from a star moving away from an observer shows longer wavelengths, shifting towards the red end of the spectrum.

Nebula

A dense cloud-like collection of gas and dust in space, often sites of star formation.

Spiral Galaxy

A type of galaxy characterized by long arms that spiral out from a central core; the Milky Way is an example.

Elliptical Galaxy

A galaxy with an ellipse shape, ranging from spherical to elongated, containing some of the oldest stars.

Irregular Galaxy

A galaxy without a regular shape, rich in gas and dust, serving as the building blocks of stars.

Star Clusters

Groups of stars found within galaxies; includes globular clusters (hundreds of thousands of stars) and open clusters (up to a few thousand stars).

The Milky Way

A spiral galaxy containing approximately 200 billion stars, where our solar system is located.

Local Group

A cluster of about 40 galaxies, including the Milky Way and Andromeda, approximately 10 million light-years in diameter.

Exoplanets

Planets outside our solar system; there may be trillions of such planets in the galaxy.

Transit Method

A technique to detect exoplanets by observing dips in stellar brightness as a planet passes in front of the star.

Habitable Zone

The region around a star allowing for liquid water to exist, crucial for the potential of life.

Light Curve

A graph plotting a star's brightness over time, used to analyze properties of exoplanets.