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Sun : (1) the luminous celestial body around which the earth and other planets revolve, from which they receive heat and light, which is composed mainly of hydrogen and helium, and which has a mean distance from earth of about 93,000,000 miles (150,000,000 kilometers), a linear diameter of 864,000 miles (1,390,000 kilometers), and a mass 332,000 times greater than earth (2) a celestial body like the Sun — Webster

Oxford, OneLook, Free Dictionary, Wiktionary, InfoPlease, Word Reference, Urban Dictionary


Roget’s II (, Merriam-Webster Thesaurus, Visuwords


Solar Physics Glosary (NASA)


The Sun is the star at the center of the Solar System. It is a nearly perfect sphere of hot plasma, with internal convective motion that generates a magnetic field via a dynamo process. It is by far the most important source of energy for life on Earth. Its diameter is about 109 times that of Earth, and its mass is about 330,000 times that of Earth, accounting for about 99.86% of the total mass of the Solar System. About three quarters of the Sun’s mass consists of hydrogen (~73%); the rest is mostly helium (~25%), with much smaller quantities of heavier elements, including oxygen, carbon, neon, and iron.

The Sun is a G-type main-sequence star (G2V) based on its spectral class. As such, it is informally referred to as a yellow dwarf. It formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most of this matter gathered in the center, whereas the rest flattened into an orbiting disk that became the Solar System. The central mass became so hot and dense that it eventually initiated nuclear fusion in its core. It is thought that almost all stars form by this process.

The Sun is roughly middle-aged; it has not changed dramatically for more than four billion years, and will remain fairly stable for more than another five billion years. After hydrogen fusion in its core has diminished to the point at which it is no longer in hydrostatic equilibrium, the core of the Sun will experience a marked increase in density and temperature while its outer layers expand to eventually become a red giant. It is calculated that the Sun will become sufficiently large to engulf the current orbits of Mercury and Venus, and render Earth uninhabitable. — Wikipedia

Britannica, Columbia (Infoplease)


Sun in Depth (NASA)


WolframAlpha, DuckDuckGo



Voyages to the Sun (Steven J. Dick, NASA’s Chief Historian)
Missions to Study the Sun (Planetary Society)


Quotations Page Bartlett’s


WorldCat, Library of Congress, UPenn Online Books, Open Library




OER Commons: Open Educational Resources
Open Education Consortium





Space Weather Live, News about the Sun (NASA), NPR Archives




Space Weather Prediction Center (NOAA)





The top 10 suns in art (The Guardian)


OEDILF: The Omnificent English Dictionary In Limerick Form



SpaceWeatherLive RSS Latest Space Weather news updates from the SpaceWeatherLive team.

  • Coronal hole faces Earth
    on October 10, 2017 at 3:46 pm

    A northern hemisphere coronal hole is facing our planet today. […]

  • Coronal holes faces Earth, AR2673 returns
    on September 24, 2017 at 2:09 pm

    A large southern extension of the northern hemisphere polar coronal hole is facing Earth today. […]

  • Sunspot region 2673 YouTube video
    on September 14, 2017 at 10:11 pm

    Solar activity has plunged to very low levels with the disappearance of sunspot region 2673. […]

  • Coronal mass ejection arrival
    on September 12, 2017 at 7:54 pm

    The X8.2 coronal mass ejection has arrived. A weak impact was observed at 19:29 UTC with a minor increase in the solar speed, density and the total strength of the interplanetary field (Bt). This is without a doubt the glancing blow arrival of the X8.2 coronal mass ejection as the low energy protons measured by ACE/EPAM peaked at the moment of impact, a classic sign of a CME arrival. […]

  • Coronal hole faces Earth
    on September 11, 2017 at 11:01 pm

    A southern extension of the northern hemisphere polar coronal hole is facing our planet today. It is the same coronal hole that caused minor G1 geomagnetic storm conditions for four days last month. […]