A 21st Century Model Of The Sun
The visible surface of the Sun is called the photosphere. This is the region of the Sun where energy produced in its core can finally escape the star, and fly off into space. It reaches a temperature of almost 6,000 degrees Kelvin, and gives the Sun its white/yellow appearance. | | | | |
Perhaps the most familiar feature on the surface of the Sun are sunspots. These are relatively cooler regions on the surface of the Sun, where its magnetic field lines pierce the surface of the Sun. Sunspots can be the source of solar flares and coronal mass ejections.
core
The Earth core is the innermost, hottest part of the planet that has been detected by seismological study. It is a primarily solid sphere about 1,220 km in radius. It is thought to be made up of an iron-nickel alloy with a temperature similar to the surface of the Sun (5,778 K). The make-up of the inner core can be deduced from the abundant chemical elements in the solar system.
There are two layers to the core * Inner unconnected * Outer The existence of an inner core distinct from the liquid outer core was discovered in 1936 using observations of seismic waves that partly reflect from its boundary.
The outer core was believed to be liquid due to its inability to transmit elastic shear waves. It only allows compressional waves to pass through it.
The solidity of the inner core has been difficult to establish, because the elastic shear waves that are expected to pass through it are very weak and difficult to detect.
Mercury is the innermost and smallest planet in the Solar System,[a] orbiting the Sun once every 87.969 Earth days. The orbit of Mercury has the highest eccentricity of all the Solar System planets, and it has the smallest axial tilt. It completes three rotations about its axis for every two orbits.
