Sun, star around which Earth and the other components of the solar system revolve. It is the dominant body of the system, constituting more than 99 percent of its entire mass.
Sun-Earth Day is a celebration established in 2000 by NASA and ESA. The purpose of the holiday is to popularize the knowledge about the Sun, and the way it influences life on the Earth.
 See also ...
Sun Erupts With Most Powerful Solar Flare in 4 Years
An X2.2 flare erupted from the sun's active region 1158 (at lower right) at about 0150 UT or 8:50 pm ET on Feb. 14, 2011.
View full size image ...
Sun, the solar system's only star
Stars are born. They take shape. They go through a turbulent adolescence, and then they live out their lives in a predictable pattern. Some have companions to provide for. Others rapidly decline and die. In some ways, stars are just like people.
The closest star to the Earth and the center of the solar system.
Sun and planets formed from different ingredients
DR EMILY BALDWIN
Posted: 28 June 2011 ...
How to Photograph the Sun
You have probably seen various photos where the Sun always has different color. There is no mystery about it, it all depends on the filter you have, and a filter you must use. The most obvious and desired target are... Continue reading → ...
sun at HighBeam Research
sun on Wikipedia
sun. Wikimedia Commons (Public Domain) ...
The Sun in Mythology
Creation is often linked to a combination of the Sun (Male) and Moon (Goddess) - representing duality in physical reality.
Mankind will not remain on Earth forever, but in its quest for light and space will at first timidly penetrate beyond the confines of the atmosphere, and later will conquer for itself all the space near the Sun. - Konstantin E. Tsiolkovsky
Sun Introduction ...
sun spot - Space and Astronomy Definition - Online Dictionary and Glossary ...
high sun - Space and Astronomy Definition - Online Dictionary and Glossary ...
Cepheid Variable - Space and Astronomy Definition - Online Dictionary and G...
Enchanted Learning Search
First search engine with spelling correction and pictures! ...
The sun's atmosphere consists of the chromosphere, corona, and photosphere. The photosphere is the bright visible surface of the sun, with a surface temperature of 5,800 K. The chromosphere consists of the bright gases just above the photosphere of the sun and is 10,000-15,000 km thick.
The Sun in the He II emission line.
Credit: SOHO (ESA/NASA)
The Sun is the Earth's dominant source light (and thus heat) and the star about which all of the planets of the solar system orbit. The Sun has mass 1.989 × 1030 kg and a radius of ~700,000 km.
The sun has guided human life for all of history, and it has also been the facilitator of life on our planet. It is the most obvious object in the sky, but in the grand scheme of things, the sun is an average star with no special significance.
The Sun is a star at the center of our solar system. Our Sun is a medium-sized yellow star that is 93,026,700 miles (149,680,000 km) from Earth. Its diameter is 865,121 miles (1,391,980 km).
Our Sun is gorgeous, and dangerous, and amazing. These pictures and videos are more than just beautiful; they are telling us about the mechanisms and processes occurring both on the surface and inside our nearest star. Given the impact this can have on Earth, the more we know, the better.
Wikipedia, the free encyclopedia - Cite This Source
The Sun (Sol) is the star at the center of the Solar System. The Earth and other matter (including other planets, asteroids, meteoroids, comets and dust) orbit the Sun, which by itself accounts for about 99.8% of the solar system's mass.
Sun Watching Satellite SOHO Regains Ability
Solar and Heliospheric Observatory (SOHO), the Sun-watching satellite, has regained most of its capability after having been shut down partially in June-July 2003 when its high-gain antenna froze up reducing its ability to transmit data to Earth.
Sun City Palm Desert Astronomy Club
Please contact this organization for information on their astronomy viewing schedules, telescope availability, membership, and public programs.
Sun City Palm Desert Astronomy Club ...
"Sun Observer's Guide" by Pam Spence,159 pp., Firefly Books, 2004. A concise and readable overview. Questions from Users: The color and temperature of stars and of the Sun
*** Questions about the Solar Corona:
(1) Why don't its particles separate by weight?
The Sun's Surface
The deepest layer of the Sun you can see is the photosphere. The word ``photosphere'' means ``light sphere''. It is called the ``surface'' of the Sun because at the top of it, the photons are finally able to escape to space. The photosphere is about 500 kilometers thick.
Our Sun is a yellow dwarf star. Its official designation is as a G V star. Stars in the this classification have a surface temperatures between 5,300 and 6,000 K and fuse hydrogen into helium to generate their light. They generally last for 10 billion years.
Our Sun's Lost Sibling
By Brian Ventrudo
Like most stars in the Milky Way, our Sun was born in a cluster of hundreds of new stars in a cloud of glowing gas and dust like the Orion Nebula, then settled down with its siblings in an open star cluster like the Pleiades.
When we think of stars, we usually neglect the fact that the nearest one is right in our own backyard: the Sun! The Sun is not only the dominant object in the sky during the day, but it is the source of virtually all of the light and the heat that fuels life on Earth.
Many ancient peoples worshiped the Sun as a god. They thought a solar eclipse meant the god was angry with them. They believed the Sun god's anger could only be calmed with prayer and sacrifice.
The Sun in Time
...is a program designed to integrate science and social studies curricula through a study of Solar Science and Archaeoastronomy.
Our Sun is a normal main-sequence G2 star, one of more than 100 billion stars in our galaxy. diameter: 1,390,000 km. mass: 1.989e30 kg temperature: 5800 K (surface) 15,600,000 K (core) ...
The Sun: An Introduction to the Stars
In this course, Astronomy 124, we will be learning about the contents of the universe, from the relatively small scales of a single star system up to the largest distances known, namely the entire visible universe.
1. The Sun is a star that is in the center of the Solar System
2. The Sun is recognized as having the largest mass in our Solar System.
3. The diameter of the Sun is 1.4 million km (870,000 miles) ...
Sun Wu-K'ung's first appearance in historical records dates back to a minor skirmish in the Version War in the Waterby system, then a small colonial outpost on the periphery of the Terragen expanse.
The star at the center of our solar system. An average star in terms of size and mass, the Sun is a yellow dwarf of spectral type G2. It is about 5 billion years old, contains 2 * 1030 kilograms of material, and has a diameter more than 100 times that of Earth.
Sun spots come and go on a regular basis. At times there are very few if any sun spots. Other times there are far more. They generally increase in intensity and then decrease over a period of 11 years. This 11 year cycle is known as the Saros Cycle.
Solar Flares ...
things you should know about your hamster's cage
Everyone has a dead bird story ...
The Sun. Courtesy of SOHO (ESA & NASA)The Sun is steadily converting the hydrogen in its core into helium. As the available fuel runs out the energy output declines. Outward pressure declines too and so the core of the Sun shrinks.
The Sun. Image credit: NASA
We've talked about the Sun before, but this time we're going to look at the entire life cycle of the Sun, and all the stages it's going to go through: solar nebula, protostar, main sequence, red giant, white dwarf, and more.
The Sun is one of the only two objects which can be seen year round by people around the world. The other is, of course, the Moon. The Sun is, however, the only object in the sky which can be dangerous to view.
The Sun's Corona
The sun, in x-ray wavelengths
Of all the billions and billions of stars in the universe, only one small and fairly unremarkable star really matters to us: the star without which there would be no life on Earth -- our star, the Sun.
The Sun and its entourage of planets travel in the general direction of Vega (away from Sirius), orbiting the center of the Milky Way at some 140 to 150 miles per second. Even at this breakneck speed, it takes something like 225 million years for the Sun to complete one revolution around the Galaxy.
The Sun at wavelengths from x-ray to radio.
Views of the Solar System
Bill Arnett's Solar Tour
A solar virtual tour.
An excellent pictorial introduction to the sun.
Solar Heliospheric Observatory (SOHO). Solar Image Gallery.
The Sun also has an influence on the tides, but since it is further away, it doesn't pull as strongly. However, when both the Moon and the Sun are pulling along the same axis, the tides are highest.
"The sun strings these worlds - the earth, the planets, the atmosphere - to himself on a thread." ...
How did the sun's family of planets and minor bodies originate?
How did the solar system evolve to its current diverse state?
How did life begin and evolve on Earth, and has it evolved elsewhere in the Solar System?
A model of the Sun shows its nuclear fusing core (where hydrogen is turned into helium by the conversion of mass into energy), an envelope where energy is transferred by radiation, and an outer layer where convection (the rising of hot gases, falling of cool gases) rules.
Observing Where the Sun Sets
Grade Level: 3-5
Lesson Time: Less Than 30 Minutes
Body: Sun, Earth
Mission: Earth Science Missions (Earth), Heliophysics Missions (Sun) ...
Set it on a flat surface and rotate the base of the fixture so that the North Pole is farthest away from an imaginary light source (the Sun). This simulates winter in the northern hemisphere; summer in the southern hemisphere. For illustrative purposes, let's consider Alaska.
Thus, in the Copernican model the Sun was at the center, but the planets still executed uniform circular motion about it. As we shall see later, the orbits of the planets are not circles, they are actually ellipses.
Analysis of data from GONG and other sources shows that current theories about the structure of the Sun need to be expanded.
The Sun will appear directly opposite it on the sky, so subtract 12h from the right ascension (or add 12h, as the case may be), and change the sign of the declination. That puts the Sun at 5h 57.8m, -4° 42', in the constellation Orion as seen from Barnard's Star.
Welcome to the Tour of Our Sun! The following pages will tell you about how scientists are studying our Sun this very minute.
There are about eight main pages to this tour with lots of hyperlinks to more technical information. Be sure to watch several of our solar movies - they're really cool!! ...
Sun and Planets
The following table compares major features of the Sun and planets, and relates many planetary characteristics to Earth's own:
Sun redirects here. For information on Earth's sun, see Sol. You may be searching for the actress Star.
Sun Liang was an emperor of Eastern Wu during the Three Kingdoms period. He was the founding emperor Sun Quan's youngest son and heir.
Sun: The Sun is a star and the biggest object in the Solar System, it burns brightly in the center as planets and other objects orbit around it. It has a diameter around 110 times bigger than the Earth’s and is located around 150 million kilometres (93 million miles) away.
Sun: One of the 100 billion stars in our galaxy. 1,390,000 km diameter. Temperature at the core: 15,600,000 K. Temperature at the surface: 5800 K.
Sun: The star associated with Earth's solar system. The Sun weighs about 2x1030 kilograms, and is about 1.4x109 meters in diameter.
Supergiant: Very luminous star 10-1000 time more massive than the Sun.
Sun synchronous orbit -- A spacecraft orbit that precesses, wherein the location of periapsis changes with respect to the planet's surface so as to keep the periapsis location near the same local time on the planet each orbit. See walking orbit.
The star at the centre of our solar system, providing the light and heat required for life on Earth.
A device used to determine the time of day by observing shadows cast by a gnomon.
SUN - Our parent star. The structure of Sun's interior is the result of the hydrostatic equilibrium between gravity and the pressure of the gas. The interior consists of three shells: the core, radiative region, and convective region.
(a) The star that Earth orbits. The Sun is a yellow main-sequence star that is spectral type G2, shines with apparent magnitude -26.74, and has an absolute magnitude of +4.83. The Sun is 4.6 billion years old.
Sun, Mercury, Venus, Earth, Moon, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto, Quaoar, Asteroids, Comets, Sedna ...
The Sun Is Moved To The Center
They explained this by assuming the planets and stars (as well as the Moon and Sun) were fixed on large, concentric, invisible, rotating spheres with the Earth at their center.
Our sun is located in the Orion arm of the Milky Way between the inner Sagittarius arm and the outer Perseus arm of our galaxy. Just outside the Perseus arm is the outermost Cygnus arm. Between the Sagittarius arm and the galactic center are the Scutum-Crux arm and the innermost Norma arm.
The Sun →
08.18.09 - Read about Earth's sun, and learn a song, too!
What Is NASA?
THE SUN IN X-rays
What sort of radiation is emitted by a gas of 1,000,000 K? Unlike the 5800 K photosphere, which emits most strongly in the visible part of the electromagnetic spectrum, the hotter coronal gas radiates at much higher frequencies"primarily in X-rays.
Mean Sun. An imaginary Sun travelling at a speed equal to the average rate that the real Sun travels along the ecliptic.
Mean. The average of a series of values.
Megaparsec. One million parsecs, a distance equal to 3 260 000 light years.
The Sun is the brightest object in our sky with an apparent magnitude of -26.8. The giant star Canopus (Alpha Carinae) lying 310 light years (ly) from earth is the second brightest star in the night sky. Canopus has an apparent magnitude of -0.74. How much brighter does the Sun appear than Canopus?
and âˆ´ Sun's diameter = 1,390,000 km (or 1.39 Ã- 109 m).
If a star is 20 parsecs away and has an apparent magnitude of +6, what is its absolute magnitude?
1) Why the Sun and Moon live in the sky Retold and Illustrated by Niki Daly $15.00 (hardcover) African Myth - This book was also found on the shelf of Barnes and Nobles ...
Sun, Moon & Planets - now!
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Sun The star at the center of our solar system. It is made mostly of hydrogen and helium with traces of heavier elements. This image of the Sun is courtesy of SOHO/EIT.
More about the Sun...
Sun-centered; using the sun rather than the earth as the point to which we refer. A heliocentric measurement, for example, omits the effect of the Doppler shift caused by the earth's orbital motion.
helium - (n.)
atom consisting of two protons and two electrons.
Sun, for example, the immense pressures and temperatures of the interior ionize the atom into free protons and electrons and so turn hydrogen into a nuclear fuel (see NUCLEOSYNTHESIS).
A sun like star is dying. It becomes
? a brown dwarf.
? a yellow giant;
? a red super giant
? a red giant.
No sun tan lotion required
Pluto is situated so far out in the depths of the solar system that if you were to stand on its surface the sun would just look like a bright star.
Size matters ...
The Sun shining through the Stonehenge monument. Sun rise on the summer solstice was the most important time the Sun would shine through the monument.
Click on image for full size
Windows to the Universe original image ...
The sun passes this constellation from late July to early August. In former times the Sun used to lie in this constellation when it reaches the its point farthest north - the time of the summer solstice.
The Sun and Earth pass through Saturn's ring plane on August 10th and September 4th, 2009. However, unlike the Saturn ring plane crossing of 1995, the 2009 events will occur when Saturn, viewed from Earth, is close to the sun.
The Sun is in Pisces from March 13 to April 19, and it crosses the ecliptic on March 21, which marks the vernal Equinox, the first day of autumn in the southern hemisphere. This used to be called the first point in Aries, but precession has now moved it into Pisces.
The Sun, a spectral class G2 star that contains 99.86% of system's mass.
The planets of the solar system are those nine bodies traditionally labelled as such; Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
The Sun is in the galactic disk, about half-way from the galactic center to the outer edge of the disk. All of the stars we see in the sky are part of this disk. The stars that make that band up are close to us, because dust in the disk eventually blocks our view. At its distance of 7.
The sun is a star and a strong source of radio emission. Most ordinary stars are expected to emit radio waves since they are thermal sources. However, the majority of the radio emission from stars is undetectable since they are far away and the signals are too faint.
The Sun as seen through my 10-inch Meade Schmidt Cassegrain telescope in Orlando, Florida on 3/14/89. This image was captured on Kodak Ektachrome 100 color slide film with a Thousand Oaks full-aperture glass solar filter.
The Sun and nearby disk stars share a common orbital motion about the galactic center, but in addition each has a small random velocity, reflecting the fact that their orbits are not perfect circles.
Our sun is heading away from Columba as fast as it can go. Columba contains the "solar antapex" which is the opposite of the solar apex, which is the direction the sun is headed. Right now, we seem to be journeying toward the constellation Hercules.
The Sun, or any star for that matter, "shines" or "burns" due to a process of thermonuclear fusion, not due to a chemical reaction like the oxygen-driven fires on Earth.
The Sun is at the center of the universe and everything revolves around that. Was first proposed by Copernicus.
The study of the interior of the sun by the analysis of its modes of vibration.
The Sun's path across the sky. The Moon and the planets follow this path closely, since their orbital planes are nearly aligned with Earth's orbital plane. The ecliptic is tilted 23.5 degrees from the celestial equator.
effective temperature ...
The Sun's disk and the separation from the comet are shown to scale, with north at the top of the image and west to the right. Keep in mind that ISON will be very close to the Sun (1.5° on average, around three times the apparent diameter of the Sun).
Of the Sun.
The large cloud of gas from which the Sun and planets were formed 4,600 million years ago.
If the sun were replaced by Betelgeuse, the surface of the star might stretch out beyond the asteroid belt. The planets out to the orbit of Mars would be engulfed by the star.
The sun and moon both exert gravitational pull on the earth. This pull has a definite affect on the earth's rotation, because the earth is not perfectly spherical. The earth bulges at the equator.
On the Sun, an extended H-alpha emission feature of an active region that is seen from the time of emergence of the first magnetic flux until the widely scattered remnant magnetic fields merge with the background.
In the Sun convection is also an important process. Convection becomes important whenever the opacity goes up and the rate of radiative diffusion becomes less. Then heat builds up and the boiling begins. Radiative diffusion is most important in the inner 80% of the Sun, convection in the outer 20%.
One of the Sun's outer layers, visible for a few minutes as a spectacular halo during during a total eclipse of the Sun.
A reddish-colored layer in the solar atmosphere, just above the photosphere.
The Sun when visible at midnight, which happens only in summer north of the Arctic Circle or south of the Antarctic Circle.
Our own galaxy.
On nearing the Sun, a comet may develop two tails. The solar wind of high-speed protons and electrons sweeps cometary ions in a direction away from the Sun, producing a straight plasma or ion tail. A second tail consisting of dust particles about a micrometer in size may appear.
Kepler-20: A Sun-like Star with Three Sub-Neptune Exoplanets and Two Earth-size Candidates
March 17, 2012 GAUTIER Th., CHARBONNEAU D., ROWE J., MARCY G., ISAACSON H., TORRES G. & 38 additional authors
ApJ., 749, 15
paper arxiv ...
active (of the sun; characterized by a high level activity in sunspots and flares and radio emissions)
stargaze (observe the stars)
go down; go under; set (disappear beyond the horizon) ...
See also: Astro, Earth, Planet, Solar, Star