Astrophysics, definition and study. A-Z index of Cognitio.

Astrophysics is the branch of astronomy or physics that studies physical properties, that is, all the various phenomena of celestial matter. The traditional scope of astrophysics includes the physical properties of stars, galaxies, half interstellar, and half intergalactic, and any other forms of matter present in the universe; It also studies the formation and evolution of the universe as a whole, called Cosmology.

Cosmology, definition and study. A-Z index of Cognitio.

Cosmology

Though astronomy is as ancient as the story itself, it was long kept separate from the study of physics. In the Aristotelian vision of the world, the celestial world tended to perfection – where bodies in the sky seemed to be perfect spheres moving on perfectly circular orbits – while the earthly world seemed destined for imperfection; these two kingdoms were not seen as related. At the end of the nineteenth century, it was discovered that by shattering the sunlight they could observe a multitude of spectral lines. Hot gas experiments showed that the same lines can be observed in the gas spectra, specific lines corresponding to unique chemical elements. In this way, it was proven that the chemical elements found in the Sun (main hydrogen) were also found on Earth.

Sun, definition and study. A-Z index of Cognitio.

Sun

Indeed, the helium element was first discovered in the Sun’s spectrum and only later on Earth, hence its name. During the 20th century, spectroscopy (the study of these spectral lines) progressed, particularly as a result of the advent of quantum physics that was needed to understand astronomical observations and experiments. From the space, we receive mostly electromagnetic radiation (photons), but also some particles (cosmic and neutrino rays). Most astrophysical phenomena are not directly observable: for example, consider the processes that provide the energy that the Sun radiates into space, occurring in the deepest areas of the Sun, or the Big Bang, which occurred about 13.7 billions of years ago.

Astrophysics, definition and study. A-Z index of Cognitio.

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Astrophysics, definition and study. A-Z index of Cognitio.

Astrophysics