ASTROPHYSICS: OBJECT OF STUDY, HISTORY, THEORIES, BRANCHES - ARTE - 2025

The astrophysics is responsible for combining the approaches of physics and chemistry to analyze and explain all bodies in space as stars, planets, galaxies, and so on. It appears as a branch of astronomy and is part of the sciences related to the study of the Universe.

Part of the object of study has to do with the search for understanding the origin of life in the Universe and the function or role of human beings within it. For example, try to discover how environments with favorable conditions for the development of life develop within a planetary system.

Astrophysics studies objects in space in terms of their structure and chemical and physical composition. The electromagnetic spectrum is your main source of information. Image by WikiImages from Pixabay

Object of study

Astrophysics has the object of study to explain the origin and nature of astronomical bodies. Some of the factors it looks at are density, temperature, chemical composition, and luminosity.

This branch of astronomy uses the electromagnetic spectrum as the main source of information for any astronomical objective in the universe. Planets, stars and galaxies, among others, are studied. Today, in addition, it focuses on more complex or distant targets such as black holes, dark matter or dark energy.

Much of the modern technology implemented in the astrophysical approach makes it possible to obtain information through light. With the study of the electromagnetic spectrum, this discipline is capable of studying and knowing both visible and invisible astronomical bodies to the human eye.

History of astrophysics

The emergence of astrophysics as a branch of astronomy occurs during the nineteenth century. Its history is full of relevant antecedents in which chemistry is closely related to optical observations. Spectroscopy is the most crucial study technique for the development of science and is responsible for analyzing the interaction between light and matter.

Spectroscopy, as well as the establishment of chemistry as a science, were elements that notably influenced the advancement of astrophysics. In 1802 William Hyde Wollaston, chemist and physicist of English origin, discovers some dark traces in the solar spectrum.

Later the German physicist Joseph von Fraunhofer notes on his own that these traces of the sun's optical spectrum are repeated in stars and planets such as Venus. From here he deduced that this was an inherent property of light. The spectral analysis of light, prepared by Fraunhofer, was one of the patterns to be followed by various astronomers.

Another of the most prominent names is that of the astronomer William Huggins. In 1864, through a spectroscope that he had set up in his observatory, he was able to discover using this instrument that the chemical composition could be determined and some physical parameters of the nebulae obtained.

For example, the temperature and density could be found. Huggins's observation was made to study the nebula NGC6543, better known as "Cat's Eye."

Huggins relied on Fraunhofer's studies to apply spectral analysis of sunlight and use it in the same way for stars and nebulae. In addition to this, Huggins and the professor of chemistry at King's College London, William Miller, spent a lot of time carrying out spectroscopy studies on terrestrial elements to be able to identify them in the studies of the stars.

By the twentieth century, the quality of discoveries were held back by instrument limitations. This motivated the construction of teams with improvements that allowed the most significant progress to date.

Outstanding Theories for the Study of Astrophysics

Inflationary theory of the universe

The inflationary theory was postulated by the physicist and cosmologist Alan H Guth in 1981. It aims to explain the origin and expansion of the universe. The idea of ​​"inflation" suggests the existence of a period of time of exponential expansion that occurred in the world during its first moments of formation.

The inflationary proposal contradicts the Big Bang theory, one of the most accepted when looking for explanations of the origin of the universe. While the Big Bang expects that the expansion of the universe has slowed down after the explosion, the inflationary theory states the opposite. "Inflation" proposes an accelerated and exponential expansion of the universe that would allow great distances between objects and a homogeneous distribution of matter.

Maxwell's electromagnetic theory

One of the most interesting contributions in the history of the physical sciences is the "Maxwell equations" within his electromagnetic theory.

In 1865, James Clerk Maxwell, specialized in mathematical physics, published A dynamic theory of the electromagnetic field in which he exposed the equations through which he reveals the joint work between electricity and magnetism, a relationship that has been speculated since the 18th century..

The equations cover the different laws that are associated with electricity and magnetism, such as Ampère's law, Faraday or Lorentz's law.

Maxwell detected the relationship between the force of gravity, magnetic attraction, and light. Previously, within astrophysics only properties such as gravity or inertia were evaluated. After Maxwell's contribution, the study of electromagnetic phenomena was introduced.

Information gathering methods

The spectrometer

Physicist Gustav Kirchhoff and chemist Robert Bunsen, both Germans, were the creators of the first spectrometer. In 1859 they demonstrated that each substance in its pure state is capable of transmitting a specific spectrum.

Spectrometers are optical instruments that make it possible to measure light from a specific part of an electromagnetic spectrum and subsequently identify materials. The usual measurement is made by determining the intensity of the light.

The first spectrometers were basic prisms with gradations. At present they are automatic devices that can be controlled in a computerized way.

Astronomical photometry

Within astrophysics, the application of photometry is important, since much of the information comes from light. The latter is responsible for measuring the intensity of light that may come from an astronomical object. It uses a photometer as an instrument or it can be integrated into a telescope. Photometry can help determine, for example, the possible magnitude of a celestial object.

Astrophotography

It is about the photography of astronomical events and objects, this also includes areas of the sky at night. One of the qualities of astrophotography is to be able to translate distant elements into images, for example, galaxies or nebulae.

Branches implemented in observational astrophysics

This discipline focuses on data collection through the observation of celestial objects. It uses astronomical instruments and the study of the electromagnetic spectrum. Much of the information obtained within each subbranch of observational astrophysics has to do with electromagnetic radiation.

Radio astronomy

Its object of study is celestial objects that are capable of emitting radio waves. It pays attention to astronomical phenomena that are usually invisible or hidden in other portions of the electromagnetic spectrum.

For observations at this level, a radio telescope is used, an instrument designed to perceive radio wave activities.

Infrared astronomy

It is a branch of astrophysics and astronomy in which infrared radiation from celestial objects in the universe is studied and detected. This branch is quite wide since all objects are capable of emitting infrared radiation. This implies that this discipline encompasses the study of all existing objects in the universe.

Infrared astronomy is also capable of detecting cold objects that cannot be perceived by optical instruments that work with visible light. Stars, particle clouds, nebulae and others are some of the space objects that can be perceived.

Optical astronomy

Also known as visible light astronomy, it is the oldest study method. The most widely used instruments are the telescope and spectrometers. This type of instrument works within the range of visible light. This discipline differs from the previous branches because it does not study invisible light objects.

Artist's impression of a gamma ray burst

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Gamma ray astronomy

It is the one in charge of studying those phenomena or astronomical objects that are capable of generating gamma rays. The latter are radiation of very high frequency, higher than X-rays, and their source is a radioactive object.

Gamma rays can be located in very high energy astrophysical systems such as black holes, dwarf stars or supernova remnants, among others.

Relevant concepts

Electromagnetic spectrum

It is an energy distribution range related to electromagnetic waves. In relation to a specific object, it is defined as the electromagnetic radiation that is capable of emitting or absorbing any object or substance both on Earth and in space. The spectrum includes both light visible to the human eye and that which is invisible.

Astronomical object

In astronomy, an astronomical or celestial object is called any entity, set or physical composition that is found naturally within the observable part of the universe. Astronomical objects can be planets, stars, moons, nebulae, planetary systems, galaxies, asteroids, and others.

Radiation

It refers to the energy that can come from a source and travel through space and even be able to penetrate other materials. Some known types of radiation are radio waves and light. Another type of familiar radiation is "ionizing radiation" that is generated through sources that emit charged particles or ions.

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