Gourt > Science > Astronomy > Solar System > Sun (5)
| Observation data | |
|---|---|
| Mean distance from Earth | 149.6 km (92.95 mi) (8.31 minutes at the speed of light) |
| Visual brightness (V) | −26.8m |
| Absolute magnitude | 4.8m |
| Spectral classification | G2V |
| Orbital characteristics | |
| Mean distance from Milky Way core | ~2.5 km (26,000-28,000 light-years) |
| Galactic period | 2.25-2.50 a |
| Velocity | 217 km/s orbit around the center of the Galaxy, 20 km/s relative to average velocity of other stars in stellar neighborhood |
| Physical characteristics | |
| Mean diameter | 1.392 km (109 Earth diameters) |
| Circumference | 4.373 km (342 Earth diameters) |
| Oblateness | 9 |
| Surface area | 6.09 km² (11,900 Earths) |
| Volume | 1.41 km³ (1,300,000 Earths) |
| Mass | 1.9891 kg | (332,950 Earths)
| Density | 1.408 g/cm³ |
| Surface gravity | 273.95 m s-2 | (27.9 g)
| Escape velocity from the surface | 617.54 km/s |
| Surface temperature | 5780 K |
| Temperature of corona | 5 MK |
| Core temperature | ~13.6 MK |
| Luminosity (Lsol) | 3.827 W 3.9 lm or 100 lm/W efficacy |
| Mean Intensity (Isol) | 2.009 W m-2 sr-1 |
| Rotation characteristics | |
| Obliquity | 7.25° (to the ecliptic) 67.23° (to the galactic plane) |
| Right ascension of North pole | 286.13° (19 h 4 min 30 s) |
| Declination of North pole | +63.87° (63°52' North) |
| Rotation period at equator | 25.3800 days (25 d 9 h 7 min 13 s) |
| Rotation velocity at equator | 7174 km/h |
| Photospheric composition (by mass) | |
| Hydrogen | 73.46 % |
| Helium | 24.85 % |
| Oxygen | 0.77 % |
| Carbon | 0.29 % |
| Iron | 0.16 % |
| Neon | 0.12 % |
| Nitrogen | 0.09 % |
| Silicon | 0.07 % |
| Magnesium | 0.05 % |
| Sulphur | 0.04 % |
About 74% of the Sun's mass is hydrogen, 25% is helium, and the rest is made up of trace quantities of heavier elements. The Sun is about 4.6 billion years old and is about halfway through its main-sequence evolution, during which nuclear fusion reactions in its core fuse hydrogen into helium. Each second, more than 4 million tonnes of matter are converted into energy within the Sun's core, producing neutrinos and solar radiation. In about 5 billion years, the Sun will evolve into a red giant and then a white dwarf, creating a planetary nebula in the process.
The Sun is a magnetically active star; it supports a strong, changing magnetic field that varies year-to-year and reverses direction about every eleven years. The Sun's magnetic field gives rise to many effects that are collectively called solar activity, including sunspots on the surface of the Sun, solar flares, and variations in the solar wind that carry material through the solar system. The effects of solar activity on Earth include auroras at moderate to high latitudes, and the disruption of radio communications and electric power. Solar activity is thought to have played a large role in the formation and evolution of the solar system, and strongly affects the structure of Earth's outer atmosphere.
More on [ Sun ]
Stars :: Astronomy
Neutrino :: Particle
GeoEye-1 Will Be A High-Res Eye In The Sky
Fri, 29 Aug 2008 14:29:00 -0400
The GeoEye-1 satellite will be capable of making out details on Earth just 16 inches across. It will be the highest resolution satellite run by a private company; it's images will be marketed to a range of governments and private customers.
Europe Considers Joining Space-Faring Nations
Tue, 19 Aug 2008 10:35:00 -0400
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Fri, 15 Aug 2008 16:18:00 -0400
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What Makes Our Solar System Special?
Fri, 08 Aug 2008 15:02:00 -0400
Researchers say that if the conditions had been slightly different for our solar system, planets could have careened into the sun or been expelled into deep space. Also: A volunteer astronomer spots a strange gaseous object some are calling a "cosmic ghost."
Phoenix Finds A Salt Compound On Mars
Fri, 08 Aug 2008 14:07:00 -0400
NASA's Phoenix Mars Lander has detected a salt found on Earth on the surface of Mars. The salt, called perchlorate, is used in fireworks and rocket fuel. The news follows the recent confirmation of the presence of water on the Red Planet.
Space Company Hopes To Cut Cost Of Launches
Thu, 07 Aug 2008 16:44:00 -0400
A private company called SpaceX has failed three times to reach orbit with one of its rockets. But the company says it's learning from its failures and still hopes to radically decrease the cost of putting objects in space.
AAS Solar Physics Division - [Greenbelt, Md] Members, organization, news, meetings, contacts.
Analemma - Explains the phenomenon - the Sun's apparent path in the sky - including simple animations.
Birmingham Solar Oscillations Network - Who they are and what they do. Also includes background information, results, data.
Meta Description: [ Birmingham Solar Oscillations Network - BiSON homepage ]
Cosmic and Heliospheric Learning Center - Based at NASA/GSFC. Includes sections about the Sun, the cosmic rays and the history of its study.
Meta Description: [ Cosmicopia at NASA/GSFC -- Home ]
Current Solar Data - An unofficial archive of NOAA GOES solar data.
Meta Description: [ maj.com: Free image hosting, picture gallery. ]
Current Solar Data - Offers real time images and observations of the Sun from a variety of ground and space sources.
Geospace Environment Modeling (GEM) - Offers documents and overview from a series of projects with focus on magnetosphere studies.
Global Oscillation Network Group - Features project overview and news of a group attempting to measure the oscillations of the Sun's interior.
Global Oscillation Network Group (GONG) - Extensive information about the group and the project, which aims to conduct a detailed study of solar internal structure and dynamics using helioseismology.
Helio- and Asteroseismology - Offers introduction to the science of solar oscillations.
How Stuff Works: Sun - In-depth illustrated description of the Sun, its surface, atmosphere, sunspots, solar prominences and solar flares.
Meta Description: [ Having cell phone trouble? Believe it or not, the culprit could be eruptions of charged particles on the Sun. This week saw one of the largest solar flares in 20 years. Learn all about that huge ball of light in the sky. ]
NASA/Marshall Solar Physics - The Solar Physics Branch of Marshall Space Flight Center's (MSFC) Space Sciences Laboratory (SSL) is composed of 15 scientists involved in various studies of the physics of the Sun.
Solar Images from SDAC - Daily pictures from the SOHO and Yohkoh space platforms, the US National Solar Observatory, and the Mauna Loa Solar Observatory.
500
Solar Orbit - The site describes the solar orbit and consequences which result out of this movement of the sun. Detailed description and downloadable program allow you to investigate further details.
Meta Description: [ Description of the solar orbit. Consequences for the source of energy in the sun. ]
Stanford Solar Center - Presents a collection of educational activities based on Solar Oscillations Investigation (SOI) and Solar and Heliospheric Observatory (SOHO) data.
Meta Description: [ A collection of fun educational activities
where educators and students can explore the Sun's tangled magnetic field,
its turbulent surface motions, sounds bouncing within the solar interior, the dramatic sunspot
cycle, and even what magic happens in the solar interior where instrumen... ]
The Analemma Project - An analemma photograph is featured with a detailed description of how it was created.
Meta Description: [ Keppel Henge is a large stone circle which has been created in Canada as a millennium project. This page of the web site describes a special project that took place there. ]
The Inconstant Sun - From NASA Science News, experiment on board shuttle mission STS-107 is monitoring the Sun's variable brightness and its link to terrestrial climate change.
Meta Description: [ NASA Science News: Recording the Sun ]
The Michelson Doppler Imager - Provides results and science of an experiment flown on the SOHO spacecraft to study solar oscillations.
The Nine Planets: Sun - General information, some statistical data and links.
The Solar System in Action: Sun - General information about the star presented in a popular language.
Meta Description: [ The Sun, from ORRERY: the Solar System in action. Powerhouse of the solar system. ]
The Sun is a Ball of Iron - Dr. Oliver K. Manuel's posits a new theory of the sun's formation, composition and energy production.
Meta Description: [ New theory of the Origin of the Solar System replaces the current Solar Model. The sun is comprised mostly of Iron (Fe) ]
The Virtual Sun - Virtual tour of the sun which uses images, diagrams, and movies to illustrate subjects such as solar wind, solar flares, the solar surface and sunspots.
Meta Description: [ The Virtual Tour of the Sun offers a multimedia tour of our nearest star, the Sun. It shows you spectacular images and movies, and describes in clear terms what the amazing phenomena are. ]
The Virtual Sun - A virtual tour with basic information. Some movies also available.
Views of the Solar System: Sun - Pictures, animations, general information and data.
Meta Description: [ 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. The Sun's outer visible layer is called the photosphere ]
Windows to the Univers: Sun - Overview including general information, data, pictures, news, historical and mythological background.
500
World Book: Sun - Basic features and facts.
YPOP Tour of the Sun - Educational information about the Sun.
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