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Related Category: Astronomy: General
in astronomy: see photosphere.
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Photosphere - luminous, apparently opaque layer of gases that forms the visible surface of the sun or any other star.

Granules are small (about 1000 km across) cellular features that cover the entire Sun except for those areas covered by sunspots.

A convective cell in the solar photosphere.
gravitational attraction
See gravity.

Granule - A bright convective cell or current of gas in the Sun's photosphere. Granules appear bright because they are hotter than the descending gas that separates them ...

supergranule: A large granule on the sun's surface including many smaller granules.
superluminal expansion: The apparent expansion of parts of a quasar at speeds greater than the speed of light.

Granules are regions of the sun where hot solar material comes to the solar surface. Granules are about 600 miles (1,000 km) across and only exist for about 5 to 10 minutes before they fade away.

Gray granules covering most of the crater floor surrounding Opportunity contain hematite, said Dr.

Each granule forms the topmost part of a solar convection cell. Spectroscopic observation within and around the bright regions shows direct evidence for the upward motion of gas as it "boils" up from within.

Figure 2. Granules on the surface of the Sun. Each bubble is around 1000 km in size. The differences in the shades is due to temperature differences, with lighter areas being hotter. Image courtesy of NASA's Solar Physics Research Site.

granules Small bright features of the photosphere of the sun, covering 50 to 60 percent of the surface. They have been likened in appearance to rice grains. graph A diagram indicating the relationship between two or more variables.

granule (SOHO Glossary - GSFC) A roughly circular region on the Sun whose bright center indicates hot gases rising to the surface, and whose dark edges indicate cooled gases that are descending towards the interior.

granule (solar) small, roundish patch of dark nebulosity that may be the precursor of a protostar. grating optical surface (transmissive or reflective) upon which is ruled a large number of finely spaced grooves.

Hot gas rises in the middle of each granule bringing energy from the interior to the surface and sinks back down on the border of a granule. The hot gas rising in the center is brighter than the cooler gas sinking at the borders.

The surface of the sun consists of convection cells termed granules. The granules have diameters of 1000 km and lifetimes of 5-10 min and are observable in visible light.

Intergranular - angular interstices between feldspars occupied by pyroxene granules (very small grains).
Intersertal - interstices filled with a mixture of glass and some pyroxene.

Traditionally, active carbons are made in particular form as powders or fine granules less than 1.0 mm in size with an average diameter between .15 and .25 mm. Thus they present a large surface to volume ratio with a small diffusion distance.

The Sun's photosphere is composed of convection cells called granules-cells of gas each approximately 1000 kilometres in diameter with hot rising gas in the center and cooler gases falling in the narrow spaces between them.

How fast are these bits and pieces and granules moving around in the stream?

February 1, 2004: The crater floor surrounding Opportunity is covered with gray granules containing hematite.

Solar faculae are bright spots that form in the canyons between solar granules, short-lived convection cells several thousand kilometers across that constantly form and dissipate over timescales of several minutes.

Each granule lasts about 5 minutes on the average and represents a temperature roughly 300 higher than the surrounding dark areas. At any one time, granules cover about one-third of the solar photosphere. [H76]
Graticule ...

8 million kilometres across, with huge spots covering its surface (granules blown up large) and clouds of boiling plasma. As it expands, it reaches 772.5 million kilometres across.

4. Using a hand lens to observe the granules, have individuals sketch granules of each substance, taking care not to confuse nor mix the samples.

A meteorite with embedded pebble-sized granules that contain significant quantities of organic (complex carbon-rich) matter.
Cassegrain telescope ...

granulation: The cellular structure of the photosphere. "Granules" are formed by convection, each one is quite large, about 700 to 1000 km (400 - 600 miles) in diameter.
H ...

Cellular structure of the photosphere visible at high spatial resolution. Individual granules, which represent the tops of small convection cells, are 200 to 2000 km in diameter and have lifetimes of 8 to 10 minutes.
Greenwich Mean Time (GMT) ...

The second-of-arc scale mottled pattern in the solar photosphere. Individual granules last for a few minutes and are thought to be the tops of convection cells.

Intergranular lanes are dark, cool areas between granules where material is descending below the surface of the Sun.

The surface of the Sun can be seen, through a telescope (SEE WARNING), to have a granular appearance. These granules are the convection cells that carry the energy from below the apparent surface.

The Sun's surface in 3D. Note the sunspots neat top right. Hundreds of solar granules, each about 1,000 km across are visible in the image.

Spectra of the centers of the granules shows these regions to be a few hundred Kelvin hotter than the surrounding darker lanes. Individual granuales last for about 20 minutes.

See also: See also: Granules, Solar, Sun, Earth, Astro

Astronomy  Granulation  Granules

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