Magnitude Scale – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is the Magnitude Scale in Astronomy? In astronomy, the magnitude scale is a logarithmic scale used to measure the brightness of celestial objects such as stars, planets, and galaxies. The concept of magnitude dates back to ancient Greek astronomers who classified stars based on their apparent brightness. The modern magnitude scale was developed … Read more

Quantum Foam – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is Quantum Foam? Quantum foam is a term used in theoretical physics to describe the turbulent and fluctuating nature of spacetime at extremely small scales. According to quantum mechanics, at the most fundamental level of reality, spacetime is not smooth and continuous, but rather composed of tiny, ever-changing bubbles of energy and spacetime … Read more

Redshift-Space Distortion – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is Redshift-Space Distortion? Redshift-space distortion is a phenomenon in astronomy that occurs when the observed redshift of galaxies is affected by their peculiar velocities. In simple terms, redshift-space distortion refers to the apparent stretching or compression of galaxy clusters along the line of sight due to their motion through space. This distortion can … Read more

AB Magnitude System – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is the AB Magnitude System? The AB Magnitude System is a standardized system used in astronomy to measure the brightness of celestial objects, such as stars, galaxies, and other astronomical bodies. It was developed by astronomers Arlo Landolt and Alan Dressler in the 1980s as a way to provide a more consistent and … Read more

Lomb-Scargle Periodogram (time series analysis) – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is the Lomb-Scargle Periodogram? The Lomb-Scargle Periodogram is a method used in time series analysis to detect periodic signals in unevenly sampled data. It was developed by Lomb in 1976 and later refined by Scargle in 1982. This technique is particularly useful in fields such as astronomy, where observations may be taken at … Read more

Poynting-Robertson Effect – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is the Poynting-Robertson Effect? The Poynting-Robertson Effect, named after John Henry Poynting and Howard P. Robertson, is a phenomenon in astrodynamics that describes the effect of radiation pressure on small particles in space. When a small particle, such as a dust grain or asteroid, is exposed to sunlight, it absorbs and re-emits photons, … Read more

Azimuth – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is Azimuth? Azimuth is a term used in astronomy and navigation to describe the direction of a celestial object or point on the horizon, measured clockwise from true north. It is an angular measurement that helps determine the position of an object in the sky or on the Earth’s surface. Azimuth is often … Read more

Friedmann Equations – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What are the Friedmann Equations? The Friedmann Equations are a set of equations in cosmology that describe the expansion of the universe. They were first derived by the Russian physicist Alexander Friedmann in the 1920s, and later refined by Belgian physicist Georges Lemaître. These equations are a key component of the Friedmann-Lemaître-Robertson-Walker (FLRW) metric, … Read more

Cepheid Variable – Definition & Detailed Explanation – Astronomical Units & Measurements Glossary

I. What is a Cepheid Variable? Cepheid Variables are a type of pulsating star that expands and contracts in a regular cycle, causing their brightness to fluctuate over time. These stars are named after the first known example, Delta Cephei, which was discovered in the constellation Cepheus. Cepheid Variables are important tools for astronomers because … Read more