## Jansky (Jy) – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is a Jansky (Jy)? In the field of astronomy, the Jansky (Jy) is a unit of measurement used to quantify the flux density of electromagnetic radiation. Named after the pioneering radio astronomer Karl Jansky, the Jansky is equivalent to 10^-26 watts per square meter per hertz. This unit is commonly used to measure … Read more

## Planck Mass – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is Planck Mass? Planck Mass is a fundamental constant in physics that is derived from Planck’s constant, the speed of light, and the gravitational constant. It is the mass scale at which quantum mechanical effects of gravity become significant. In other words, it is the mass at which the quantum effects of gravity … Read more

## Planck Energy – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is Planck Energy? Planck Energy is a fundamental unit of energy in physics that is derived from the Planck constant, a fundamental physical constant that plays a crucial role in quantum mechanics and the theory of relativity. Named after the German physicist Max Planck, the Planck Energy represents the energy scale at which … Read more

## Doppler Cooling – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is Doppler Cooling? Doppler cooling is a technique used in physics to slow down the movement of atoms or ions by using laser light. This process is based on the principle of the Doppler effect, which states that the frequency of light emitted or absorbed by an object changes depending on the relative … Read more

## Kerr Metric – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is the Kerr Metric? The Kerr Metric is a mathematical solution to the equations of general relativity that describe the spacetime around a rotating black hole. It was first derived by the physicist Roy Kerr in 1963 and is named after him. The Kerr Metric is a key tool in understanding the behavior … Read more

## Transverse Velocity – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is Transverse Velocity? Transverse velocity is a term used in astronomy to describe the speed at which an object moves across the sky, perpendicular to the line of sight from the observer. In other words, it is the velocity of an object in the plane of the sky. This type of velocity is … Read more

## De Sitter Universe – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is the De Sitter Universe? The De Sitter Universe is a theoretical model of the universe proposed by Willem de Sitter in 1917. It is a solution to Einstein’s field equations of general relativity that describes a universe with a positive cosmological constant and no matter or radiation. In this model, the universe … Read more

## Angular Diameter Distance – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is Angular Diameter Distance? Angular diameter distance is a fundamental concept in astronomy that is used to measure the physical size of an object in the sky based on its apparent size and distance from Earth. It is defined as the ratio of an object’s physical size to its angular size as seen … Read more

## Jeans Length – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is Jeans Length? Jeans Length is a concept in astrophysics that refers to the minimum size that a cloud of gas must have in order for gravitational forces to overcome thermal pressure and allow the cloud to collapse and form stars. Named after the British physicist Sir James Jeans, who first proposed the … Read more

## Color-Magnitude Diagram (CMD) – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is a Color-Magnitude Diagram (CMD)? A Color-Magnitude Diagram (CMD) is a graphical representation used in astronomy to display the relationship between the color and brightness of stars in a particular region of the sky. The vertical axis of a CMD represents the magnitude or brightness of stars, while the horizontal axis represents the … Read more