Sun questions

Coronal holes generally discharge solar wind at a speed about twice the average. The escaping solar wind is known to travel along open magnetic field lines that pass through the coronal hole area. Since coronal holes are regions in the Sun’s corona that have much lower densities and temperatures than most of the corona, these regions are very thin. This thinness contributes to the solar wind since particles within the chromosphere can more easily break through.

The Earth revolves around the sun, not the other way around.

By far most of the solar system's mass is in the Sun itself: somewhere between 99.8 and 99.9 percent. The rest is split between the planets and their satellites, and the comets and asteroids and the dust and gas surrounding our star.

The astronomical unit (AU) represents the mean distance between the Earth and our sun. An AU is approximately 93 million miles (150 million km). It’s approximately 8 light-minutes.

The distance is exactly 92.96 million mi. It varies every season, but this is the average distance.

The Sun is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. Hot plasmas (thermal plasmas) have electrons and the heavy particles at the same temperature, i.e. they are in thermal equilibrium with each other. Cold plasmas (nonthermal plasmas) on the other hand have the ions and neutrals at a much lower temperature, whereas electrons are much "hotter".

The photosphere is a layer below which the Sun becomes opaque to visible light. It is tens to hundreds of kilometers thick, and is slightly less opaque than air on Earth. Because the upper part of the photosphere is cooler than the lower part, an image of the Sun appears brighter in the center than on the edge or limb of the solar disk, in a phenomenon known as limb darkening.

The sun performs a full turn around the center of our galaxy during 225 million years.

Halo is the name for a family of optical phenomena produced by light interacting with ice crystals suspended in the atmosphere. Halos can have many forms, ranging from colored or white rings to arcs and spots in the sky. Among the best known halo types are the circular halo (properly called the 22° halo), Other common optical phenomena involving water droplets rather than ice crystals include the glory and the rainbow.

Kepler is a space observatory launched by NASA to discover Earth-size planets orbiting other stars. Named after astronomer Johannes Kepler, the spacecraft was launched on March , 2009, in. Designed to survey a portion of our region of the Milky Way to discover Earth-size exoplanets in or near habitable zones and estimate how many of the billions of stars in the Milky Way have such planets,