Sun
Overview
Star
A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...
at the center of the Solar System
Solar System
The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. The vast majority of the system's mass is in the Sun...
. It is almost perfectly spherical
Sphere
A sphere is a perfectly round geometrical object in three-dimensional space, such as the shape of a round ball. Like a circle in two dimensions, a perfect sphere is completely symmetrical around its center, with all points on the surface lying the same distance r from the center point...
and consists of hot plasma
Plasma (physics)
In physics and chemistry, plasma is a state of matter similar to gas in which a certain portion of the particles are ionized. Heating a gas may ionize its molecules or atoms , thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions...
interwoven with magnetic field
Magnetic field
A magnetic field is a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude ; as such it is a vector field.Technically, a magnetic field is a pseudo vector;...
s. It has a diameter of about 1,392,000 km, about 109 times that of Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
, and its mass (about 2 kilograms, 330,000 times that of Earth) accounts for about 99.86% of the total mass of the Solar System.
Chemically, about three quarters of the Sun's mass consists of hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
, while the rest is mostly helium
Helium
Helium is the chemical element with atomic number 2 and an atomic weight of 4.002602, which is represented by the symbol He. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas that heads the noble gas group in the periodic table...
.
Unanswered Questions
Discussions
Quotations
Law, say the gardeners, is the sun, Law is the one All gardeners obey To-morrow, yesterday, to-day.
W. H. Auden in "Law, Say The Gardeners, Is The Sun"
Season of mists and mellow fruitfulness! Close bosom friend of the maturing sun
John Keats, in "Ode to Autumn"
Death comes to all, but great achievements build a monument which shall endure until the sun grows cold.
Georg Fabricius|Georg Fabricius, in praise of Georg Agricola|Georg Agricola in De Metallicis Rebus (1566); as translated by Herbert Hoover|Herbert Clark Hoover and Lou Henry Hoover|Lou Henry Hoover in the introduction to their 1912 translation of Agricola's De re metallica|De Re Metallica (1556)
There is no patent. Could you patent the sun?
Jonas Salk, in response to the question regarding his Polio vaccine, "Who owns the patent on this vaccine?" by Edward R. Murrow, in a CBS Television interview, on See It Now|See It Now (12 April 1955); quoted in Shots in the Dark : The Wayward Search for an AIDS Vaccine (2001) by Jon Cohen|Jon Cohen
Like our shadows, Our wishes lengthen as our sun declines.
Edward Young, in The Force of Religion : or Vanquished Love (1714)