Hubbleállandó

Hubbleállandó, often referred to as the Hubble constant, is a fundamental value in cosmology that describes the rate at which the universe is expanding. It is denoted by the symbol H₀. The constant relates the recessional velocity of distant galaxies to their distance from us. Essentially, the farther away a galaxy is, the faster it appears to be moving away from Earth. This relationship is known as Hubble's Law.

The value of the Hubble constant has been a subject of intense study and debate for decades. Early measurements suggested a value around 500 km/s/Mpc, but more precise observations have refined this figure considerably. Current estimates place the Hubble constant at approximately 70 kilometers per second per megaparsec (km/s/Mpc). This means that for every megaparsec (about 3.26 million light-years) farther away a galaxy is, its recession velocity increases by about 70 kilometers per second.

Determining the precise value of the Hubble constant is crucial for understanding the age, size, and ultimate fate of the universe. Different observational methods, such as measuring the distances to supernovae or analyzing the cosmic microwave background radiation, have yielded slightly different values, leading to what is known as the "Hubble tension." Resolving this tension is one of the major goals of modern cosmology.