The chromosphere is above the photosphere. Solar energy passes through this region on its way out from the center of the Sun. Faculae and flares arise in the chromosphere.
Faculae are bright luminous hydrogen clouds which form above regions where sunspots are about to form.
Flares are bright filaments of hot gas emerging from sunspot regions.
Sunspots are dark depressions on the photosphere with a typical temperature of 4,000°C (7,000°F).
The corona is the outer part of the Sun's atmosphere. It is in this region that prominences appears.
Prominences are immense clouds of glowing gas that erupt from the upper chromosphere. The outer region of the corona stretches far into space and consists of particles traveling slowly away from the Sun.
The corona can only be seen during total solar eclipses.
Introduction of Sun
The Sun is the most prominent feature in our solar system.
It is the largest object and contains approximately 98% of the total solar system mass.
One hundred and nine Earths would be required to fit across the Sun's disk, and its interior could hold over 1.3 million Earths.
The Sun's outer visible layer is called the photosphere and has a temperature of 6,000°C (11,000°F).
This layer has a mottled appearance due to the turbulent eruptions of energy at the surface.
Solar energy is created deep within the core of the Sun.
It is here that the temperature (15,000,000° C; 27,000,000° F) and pressure (340 billion times Earth's air pressure at sea level) is so intense that nuclear reactions take place.
This reaction causes four protons or hydrogen nuclei to fuse together to form one alpha particle or helium nucleus.
The alpha particle is about .7 percent less massive than the four protons.
The difference in mass is expelled as energy and is carried to the surface of the Sun, through a process known as convection, where it is released as light and heat.
Energy generated in the Sun's core takes a million years to reach its surface.
Every second 700 million tons of hydrogen are converted into helium ashes.
In the process 5 million tons of pure energy is released; therefore, as time goes on the Sun is becoming lighter.
| Sun Statistics | |
| Mass (kg) | 1.989e+30 |
| Mass (Earth = 1) | 332,830 |
| Equatorial radius (km) | 695,000 |
| Equatorial radius (Earth = 1) | 108.97 |
| Mean density (gm/cm^3) | 1.410 |
| Rotational period (days) | 25-36* |
| Escape velocity (km/sec) | 618.02 |
| Luminosity (ergs/sec) | 3.827e33 |
| Magnitude (Vo) | -26.8 |
| Mean surface temperature | 6,000°C |
| Age (billion years) | 4.5 |
Sun Prominence This image was acquired from NASA's Skylab space station on December 19, 1973. It shows one of the most spectacular solar flares ever recorded, propelled by magnetic forces, lifting off from the Sun. It spans more than 588,000 km (365,000 miles) of the solar surface. In this photograph, the solar poles are distinguished by a relative absence of supergranulation network, and a much darker tone than the central portions of the disk. (Courtesy NASA)
Comet SOHO-6 and Solar Polar Plumes
This image of the solar corona was acquired on 23 December 1996 by the LASCO instrument on the SOHO spacecraft. It shows the inner streamer belt along the Sun's equator, where the low latitude solar wind originates and is accelerated. Over the polar regions, one sees the polar plumes all the way out to the edge of the field of view. The field of view of this coronagraph encompasses 8.4 million kilometers (5.25 million miles) of the inner heliosphere. The frame was selected to show Comet SOHO-6, one of seven sungrazers discovered so far by LASCO, as its head enters the equatorial solar wind region. It eventually plunged into the Sun. (Courtesy ESA/NASA)
A New Look at the Sun This image of 1,500,000°C gas in the Sun's thin, outer atmosphere (corona) was taken March 13, 1996 by the Extreme Ultraviolet Imaging Telescope onboard the Solar and Heliospheric Observatory (SOHO) spacecraft. Every feature in the image traces magnetic field structures. Because of the high quality instrument, more of the subtle and detail magnetic features can be seen than ever before.
Solar Disk in H-Alpha This is an image of the Sun as seen in H-Alpha. H-Alpha is a narrow wavelength of red light that is emitted and absorbed by the element hydrogen. (Courtesy National Solar Observatory/Sacramento Peak)