For statistics of the Sun, click below:
The Sun has a diameter of 1,390,000 kilometers, a mass of 2 X 10^30 kilograms and a density of 1.4 grams per cubic centimeter.
The Sun supplies the energy for the existence and maintenance of nearly all living organisms on planet Earth. Solar energy influences Earth's weather.
The Sun is a star. It is a self-luminous sphere of gas held together by its own gravity and energized by nuclear fusion reactions in its interior. It moves through space with its family of planets at a speed of approximately 250 kilometers per second, in the direction of the constellation Lyra. Viewed from the Earth its angular diameter is about 0.5 degrees. The average distance is 93,000,000 miles. This makes the diameter of the Sun 811,578 miles. The Sun's equator is inclined about 7 degrees from the orbital plane of the Earth. As the Sun is mainly composed of gasses, its period of rotation is not the same all over. It is 25 Earth days at the equator and longer at higher latitudes.
The core temperature is believed to be 15 million Kelvins. The interior of the Sun is so hot that individual atoms do not exist, as high speed collisions continually knock the electrons loose from the atomic nuclei. The interior is composed of high speed nuclei and electrons moving about more or less independently, similar to a gas. This forms a fourth phase of mater called plasma, with an average density of 1.4 grams per cubic centimeter. (Imagine! a gas 1.4 times as heavy as water. That is how intense the pressure is). The temperature decreases radially outward to the visible surface of the Sun which is called the photosphere. The temperature of the photosphere has been measured to be 6000 Kelvin.
The photosphere is composed (as we believe the core is) of 94% hydrogen, 5.9% helium, and 0.1% heavier elements, the most abundant being carbon, oxygen, nitrogen, and neon.. It has a granular appearance, the granules being hot spots (about 100 K higher than the surrounding surface). that are a few hundred kilometers in diameter and last only a few minutes.
Extending more than 19,000 kilometers (12,000 miles) above the photosphere is the chromosphere (color + sphere) which is composed mainly of hydrogen. Its temperature heated by energy from shock waves is greater than the photosphere (50,000 K). It is seen as a thin, red crescent for only a few seconds during a solar eclipse. (photosphere is hidden from view). During a total solar eclipse, we can see the corona (outer solar atmosphere). Since it also receives energy from shock waves, its temperature exceeds 1,000,000 K. This high temperature gives protons, electrons, and ions enough energy to escape the Sun's atmosphere. This flow of radiation is called the solar wind with wind speeds in excess of 400 km/sec (893,000 mile per hour). The range of this wind was thought to be 50 AU, but now is believed to be 100 AU., the outer limits of the solar system. This range is known as the heliosphere.
A very distinct feature of the Sun's surface is the periodic occurrence
of Sunspots, which are patches (thousands of kilometers in diameter)
which are cooler material. There is a central dark spot called the
Umbra,
and
a lighter border called the penumbra. Sunspots are cooler
regions of the sun where magnetic energy wells up, often prior to eruptions.
Space storms occur when the sun throws off an outburst of radiation and
energetic particles that can interact with Earth's magnetic field. Such
storms can disrupt communications, damage satellites and even pose health
risks. The National Oceanic and Atmospheric Administration has set up three
scales to measure the severity of "space weather." Sunspots can be
seen from home with proper, safe viewing techniques. Astronomers suggest
projecting the sun’s image through binoculars onto a white surface. Never
look directly at the sun, however, either with the naked eye or through
binoculars or telescopes.
The number of sunspots appearance varies over a 22 year period. They can cause problems with electricity and communications on Earth. A solar storm in 1989 left six million people in eastern Canada and the northeast United States without power for nine hours as it disabled electrical transformers in Quebec. In 1998, a burst of solar radiation was implicated in the failure of the Galaxy IV communications satellite, temporarily silencing 80 percent of the pagers in North America. There were no sunspots observed from 1645 until 1715 when a mini ice age occurred, and Northern lights (Aurora Borealis) were not seen in northern Europe.
For more information click below:
Another distinct feature of the Sun's surface is the appearance of prominences that seem to be connected with violent storms in the chromosphere. They extend thousands of miles from the surface, occasionally reaching a height of 1 million miles. They appear as streamers, loops, spiral or twisted columns, fountains, curtains, or haystacks.
The Sun radiates energy because of nuclear fusion reactions inside its core, which is made up mostly of hydrogen nuclei or protons moving at very high speeds, occasionally fusing together. The products of this nuclear reaction are a deuteron (proton and neutron together), a positive electron (positron), and a neutrino. A neutrino has no (or very little) mass, no charge, travels at or near the speed of light, and hardly ever interacts with other particles such as protons or electrons. Their presence can only be detected by trapping them in a tank of 100,000 gallons of fluid tetrachloroethylene located deep in the Earth. For more details on the neutrino click below.
and here Tau Neutrino
Every second, in the Sun's interior about 600,000,000,000 kilograms of hydrogen is converted into helium and energy. Even at this rate, we expect the Sun to radiate energy from hydrogen fusion for at least 5 billion years. To find out how long it would take to consume 10% of the Sun's hydrogen, click below.
Time
to consume 10% of Sun's hydrogen
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