These are organized by a classification scheme developed exclusively for Cosma. More…
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
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
SpaceWeatherLive RSS Latest Space Weather news updates from the SpaceWeatherLive team.
Coronal hole faces Earth, Quiet Sun
on December 8, 2017 at 6:38 pm
Today we have yet another southward extension of the northern hemisphere polar coronal hole facing our planet. […]
Coronal hole faces Earth, G2 watch issued
on December 2, 2017 at 8:52 pm
A northern hemisphere coronal hole is facing our planet today. […]
The past, the present and the future
on November 27, 2017 at 5:10 pm
We've been a bit more quiet than you're used to from us during the past few weeks but our team is once more at full capacity ready to bring you the latest space weather updates. Without any further ado, let's get started! […]
Coronal hole faces Earth
on November 5, 2017 at 6:52 pm
We are currently in a very quiet period when it comes to space weather with no significant sunspot regions, solar flares or geomagnetic storms to report about but fortunately we still have the occasional coronal hole to lighten up the mood... and skies! […]
Coronal hole faces Earth
on October 21, 2017 at 8:57 am
A large southern extension of the northern hemisphere polar coronal hole is facing Earth today. […]