Convert Megaparsec (Mpc) to Electron Radius (re) instantly.
About these units
Megaparsec (Mpc)
A megaparsec is equal to one million parsecs, making it one of the principal units for describing intergalactic distances and the scale of the observable universe. Astronomers use Mpc to measure the distances between galaxies, galaxy groups, and galaxy clusters, as well as to express the scale of cosmic structures like the cosmic web. Megaparsecs are also central to cosmology because the Hubble constant — which describes the rate of cosmic expansion — is measured in units of kilometers per second per megaparsec. Thus, the Mpc sits at the heart of research on dark energy, large-scale structure formation, and the Big Bang. While hardly intuitive for everyday understanding, the megaparsec offers unmatched practicality for professional astronomy. It simplifies equations and visualization of the universe at the grandest scales.
Electron Radius (re)
The classical electron radius, approximately 2.818 × 10⁻¹⁵ meters, is a theoretical value derived from classical electromagnetic theory rather than an actual measured size. It represents the radius a charged sphere would need to have in order for its electrostatic self-energy to equal the electron's rest energy. Although electrons are now understood to be point-like or extremely small compared to this radius, the classical electron radius remains useful in scattering theory, especially in calculations involving Thomson scattering — the elastic scattering of electromagnetic radiation by free electrons. Thus, while not a physical dimension of the electron, the classical radius serves as a meaningful parameter in specific areas of physics and retains importance in radiation modeling and plasma physics.