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The Sun is 1.4 million kilometers (4.643 light-seconds) wide, about 109 times wider than Earth, or four times the Lunar distance, and contains 99.86% of all Solar System mass. The Sun is a G-type main-sequence star that makes up about 99.86% of the mass of the Solar System. [26]
From 2007 to 2009, sunspot levels were far below average. In 2008, the Sun was spot-free 73 percent of the time, extreme even for a solar minimum. Only 1913 was more pronounced, with no sunspots for 85 percent of that year. The Sun continued to languish through mid-December 2009, when the largest group of sunspots to emerge for several years ...
This will rise to 10 −6 M ☉ /year on the asymptotic giant branch, before peaking at a rate of 10 −5 to 10 −4 M ☉ /year as the Sun generates a planetary nebula. By the time the Sun becomes a degenerate white dwarf, it will have lost 46% of its starting mass. [15] The mass of the Sun has been decreasing since the time it formed.
Thus, the Sun occupies 0.00001% (1 part in 10 7) of the volume of a sphere with a radius the size of Earth's orbit, whereas Earth's volume is roughly 1 millionth (10 −6) that of the Sun. Jupiter, the largest planet, is 5.2 AU from the Sun and has a radius of 71,000 km (0.00047 AU; 44,000 mi), whereas the most distant planet, Neptune, is 30 AU ...
Solar maximum is the regular period of greatest solar activity during the Sun's 11-year solar cycle. During solar maximum, large numbers of sunspots appear, and the solar irradiance output grows by about 0.07%. [2] On average, the solar cycle takes about 11 years to go from one solar maximum to the next, with duration observed varying from 9 to ...
Solar cycles are nearly periodic 11-year changes in the Sun's activity that are based on the number of sunspots present on the Sun's surface. The first solar cycle conventionally is said to have started in 1755. The source data are the revised International Sunspot Numbers (ISN v2.0), as available at SILSO. [1]
The core of the Sun is considered to extend from the center to about 0.2 of the solar radius (139,000 km; 86,000 mi). [1] It is the hottest part of the Sun and of the Solar System . It has a density of 150,000 kg/m 3 (150 g/cm 3 ) at the center, and a temperature of 15 million kelvins (15 million degrees Celsius; 27 million degrees Fahrenheit).
The output of, for example, a photovoltaic panel, partly depends on the angle of the sun relative to the panel. One Sun is a unit of power flux, not a standard value for actual insolation. Sometimes this unit is referred to as a Sol, not to be confused with a sol, meaning one solar day. [36]