Tag: Astrophysics
-
Planetary Nebula
The phrase “planetary nebula” is a bit of a misnomer as it doesn’t actually have anything to do with planets. Instead, planetary nebulae are fascinating and colorful astronomical objects, formed when stars similar to our Sun reach the end of their lives, showcasing the incredible artistry of the universe. Introduction to Planetary Nebulae Planetary Nebulae…
-
Dark Sky Paradox
Unveiling the Paradox The Dark Sky Paradox, also known as Olbers’ Paradox, is a historical puzzle named after the German astronomer Heinrich Wilhelm Olbers, who described it in 1823. The paradox questions why the night sky is dark instead of bright, given that there are countless stars in the universe. Theoretical Explanation If we assume…
-
Solar Wind
Introduction The Solar Wind is a stream of charged particles released from the upper atmosphere of the Sun. This flow of particles is mostly composed of electrons and protons, with energies usually between 1.5 and 10 keV. It permeates the Solar System with an intensity that, although relatively weak, has a significant effect on the…
-
Andromeda Galaxy
Introduction The Andromeda Galaxy, also known as Messier 31 (M31), is a spiral galaxy approximately 2.537 million light-years away from Earth in the Andromeda constellation. It is the nearest spiral galaxy to the Milky Way, our galaxy, and is on a collision course with our galaxy, expected to occur in about 4.5 billion years. Characteristics…
-
X-Ray Astronomy
Introduction X-ray astronomy is a subfield of observational astronomy that deals with the detection and study of X-ray emission from celestial objects. X-ray radiation is absorbed by the Earth’s atmosphere, so instruments to detect X-rays must be taken to high altitude by balloons, sounding rockets, and satellites. Basics of X-ray Astronomy X-ray radiation from space…
-
Velocity Dispersion
Introduction Velocity dispersion refers to the statistical spread in velocities of particles in a system. It is a measure of how much the velocities of the particles deviate from the mean. The concept is widely used in physics and astronomy, especially in the study of galaxies and clusters of galaxies. Basic Understanding In a system…
-
Quasar
Introduction A quasar, or a quasi-stellar object (QSO), is an extremely luminous active galactic nucleus (AGN). Quasars are among the most distant objects in the universe, and their extreme brightness is generated by supermassive black holes at the center of galaxies. The Power Source of a Quasar The central engine powering quasars is a supermassive…
-
Kerr Black Hole
Introduction A Kerr black hole is a type of rotating black hole that is described by the Kerr metric in general relativity. Named after physicist Roy P. Kerr who discovered this solution in 1963, it describes a black hole rotating about an axis of symmetry. Kerr Metric The Kerr metric is given by the line…
-
Galactic Rotation Curve
Introduction A galactic rotation curve is a graph of the orbital speeds of visible stars or gas in a galaxy versus their radial distance from that galaxy’s center. It is crucial in the study of galaxy formation and evolution and has significant implications for the understanding of dark matter. Theoretical Framework Keplerian Rotation If the…
-
Hawking Radiation
Introduction Hawking Radiation is a theoretical prediction made by physicist Stephen Hawking in 1974. It is a quantum mechanical phenomenon in which black holes emit thermal radiation due to quantum effects near the event horizon. This stands in stark contrast to the classical prediction of general relativity, which asserts that black holes should not emit…