Mediaspace scheduled maintenance: Aug 25, 2026 07:00 - 12:00 AM. During this time, videos will be temporarily unavailable. Check status updates.

Lecture

Introduction to Astrophysics

Description

This lecture covers the basics of astrophysics, starting with an introduction to the field and its importance. Topics include the structure of the universe, celestial bodies, and key concepts in astrophysical research.

Official source

Ontological neighbourhood

Astronomy

Astrophysics: Physical cosmology

Related concepts (29)

Cosmology

Cosmology () is a branch of physics and metaphysics dealing with the nature of the universe. The term cosmology was first used in English in 1656 in Thomas Blount's Glossographia, and in 1731 taken up in Latin by German philosopher Christian Wolff, in Cosmologia Generalis. Religious or mythological cosmology is a body of beliefs based on mythological, religious, and esoteric literature and traditions of creation myths and eschatology. In the science of astronomy, cosmology is concerned with the study of the chronology of the universe.

Universe

The universe is all of space and time and their contents, including planets, stars, galaxies, and all other forms of matter and energy. The Big Bang theory is the prevailing cosmological description of the development of the universe. According to this theory, space and time emerged together 13.787billion years ago, and the universe has been expanding ever since the Big Bang. While the spatial size of the entire universe is unknown, it is possible to measure the size of the observable universe, which is approximately 93 billion light-years in diameter at the present day.

Physical cosmology

Physical cosmology is a branch of cosmology concerned with the study of cosmological models. A cosmological model, or simply cosmology, provides a description of the largest-scale structures and dynamics of the universe and allows study of fundamental questions about its origin, structure, evolution, and ultimate fate. Cosmology as a science originated with the Copernican principle, which implies that celestial bodies obey identical physical laws to those on Earth, and Newtonian mechanics, which first allowed those physical laws to be understood.

Observable universe

The observable universe is a ball-shaped region of the universe comprising all matter that can be observed from Earth or its space-based telescopes and exploratory probes at the present time; the electromagnetic radiation from these objects has had time to reach the Solar System and Earth since the beginning of the cosmological expansion. Initially, it was estimated that there may be 2 trillion galaxies in the observable universe, although that number was reduced in 2021 to only several hundred billion based on data from New Horizons.

Shape of the universe

The shape of the universe, in physical cosmology, is the local and global geometry of the universe. The local features of the geometry of the universe are primarily described by its curvature, whereas the topology of the universe describes general global properties of its shape as a continuous object. The spatial curvature is described by general relativity, which describes how spacetime is curved due to the effect of gravity.

Related lectures (40)

Cosmic Magnetic Fields: Generation and Backreaction

Covers the generation of primordial magnetic fields and their backreaction effects in cosmology.

Cosmological Puzzles: Dark Matter and Energy

Explores fundamental cosmological puzzles related to dark matter and energy.

The Universe: Describing Size, Mass-Energy, Geometry, and Evolution MOOC: The Radio Sky I: Science and Observations

Explores the Universe's size, mass-energy, geometry, and evolution, including redshift effects and accelerating expansion.

Hubble's Observations: Redshift and Distance MOOC: Introduction to Astrophysics

Explores Hubble's observations of the early universe, redshift, cepheid stars, and type Ia supernovae.

Inflationary Magnetogenesis: Primordial Curvature Perturbations and Magnetic Fields