The Pleiades is an open cluster consisting of approximately 3,000 stars at a distance of 400 light-years (120 parsecs) from Earth in the constellation Taurus. (It also known as “The Seven Sisters”, or the astronomical designations NGC 1432/35 and M45.)
Astrophysics – the branch of astronomy that deals with the physics of the universe, including the physical properties (luminosity, density, temperature, and chemical composition) of celestial objects such as stars, galaxies, and the interstellar medium, as well as their interactions. The study of cosmology is theoretical astrophysics at the largest scales where Albert Einstein’s general theory of relativity plays a major role.
The majority of astrophysical observations are made using the electromagnetic spectrum.
- Radio astronomy – studies radiation with a wavelength greater than a few millimeters
- Infrared astronomy – studies radiation with a wavelength that is too long to be visible but shorter than radio waves.
- Optical astronomy i- telescopes paired with a charge-coupled device or spectroscopes are the most common instruments used.
- Ultraviolet, X-ray and gamma ray astronomy study very energetic processes such as binary pulsars, black holes, magnetars, and many others.
- astronomy, physics, physical properties, luminosity, density, temperature, chemical composition, interaction, cosmology, scale, theory, relativity, light-year, parsec, radiation, wavelength, infrared, spectroscope, ultraviolet, x-ray, gamma ray, energetic