Lecture

Spectral Lines: Natural Linewidth & Broadening

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Description

This lecture covers the concept of natural linewidth and broadening in spectral lines, exploring the effects of different factors on the line width, such as collisional broadening and Doppler broadening. The instructor discusses the impact of various parameters on the spectral lines and their implications in astronomy and radio observations.

In MOOC

The Radio Sky I: Science and Observations

The serendipitous and unexpected discovery of radio emission from celestial objects opened up the possibility of studying a new and exciting view of the universe beyond the visible spectrum. Astronomers have been studying the cosmos in visible light since ancient Greece, but it is only in comparatively modern times that the universe beyond the visible spectrum has become accessible to us. In this course you will learn about the most important objects that emit in the radio regime, both within and beyond ou

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Related concepts (14)

Spectral line

A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules. These "fingerprints" can be compared to the previously collected ones of atoms and molecules, and are thus used to identify the atomic and molecular components of stars and planets, which would otherwise be impossible.

Radio astronomy

Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation coming from the Milky Way. Subsequent observations have identified a number of different sources of radio emission. These include stars and galaxies, as well as entirely new classes of objects, such as radio galaxies, quasars, pulsars, and masers.

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.

Astronomy

Astronomy is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxies, meteoroid, asteroid, and comets. Relevant phenomena include supernova explosions, gamma ray bursts, quasars, blazars, pulsars, and cosmic microwave background radiation. More generally, astronomy studies everything that originates beyond Earth's atmosphere.

Chronology of the universe

The chronology of the universe describes the history and future of the universe according to Big Bang cosmology. Research published in 2015 estimates the earliest stages of the universe's existence as taking place 13.8 billion years ago, with an uncertainty of around 21 million years at the 68% confidence level. For the purposes of this summary, it is convenient to divide the chronology of the universe since it originated, into five parts.

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