Astrophysics calculators
12 calculators Black Hole Collision Calculator Black hole merger calculator: find final mass, Schwarzschild radii, chirp mass, ISCO peak frequency, radiated energy, and ringdown frequency instantly.
Open Black Hole Temperature Calculator Calculate the Hawking temperature of any black hole from its mass, plus Schwarzschild radius, entropy, luminosity, evaporation time, and peak photon wavelength.
Open Drake Equation Calculator Use the Drake equation to estimate communicating alien civilizations in the Milky Way. Enter all 7 factors and compare optimistic, pessimistic, and 1961 scenarios.
Open Hubble Law Distance Calculator: Recessional Velocity and Cosmic Distance Calculate a galaxy's recessional velocity from its distance or vice versa using Hubble's Law. Adjust the Hubble constant, switch units, and see the step-by-step math.
Open Light Year Calculator Convert light years to km, miles, AU and parsecs - or reverse any unit. Includes step-by-step working, light travel time, and a table of 15 famous cosmic distances.
Open Luminosity Calculator Calculate star luminosity from radius and temperature via the Stefan-Boltzmann law. Get solar luminosities, watts, absolute magnitude, and apparent magnitude instantly.
Open Olbers' Paradox Calculator Calculate the expected night-sky brightness under the infinite static universe model and see exactly how finite universe age and cosmic expansion resolve Olbers' paradox.
Open Parallax Calculator: Stellar Distance from Parallax Angle Calculate stellar distance in parsecs, light-years, and AU from the parallax angle, or reverse-solve the parallax from a known distance. Step-by-step working shown.
Open Radiation Pressure Calculator Calculate radiation pressure from intensity, reflectivity, and angle. Get force, acceleration, delta-v for solar sails, and stellar interior pressure from temperature.
Open Redshift Calculator: Wavelength, Velocity and Cosmological Distance Compute redshift z from wavelength or frequency shifts. Convert z to recession velocity, lookback time, and cosmological distances using the relativistic formula.
Open Schwarzschild Radius Calculator Calculate the Schwarzschild radius (event horizon) for any mass. Enter mass in kg, solar, or Earth masses to get radius, gravitational field, and known-object comparisons.
Open Universe Expansion Calculator Calculate recession velocity, proper distance, comoving distance, and lookback time for any galaxy redshift using the Hubble constant and flat LCDM model.
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