Disk Galaxies
The term 'disk galaxies' includes all galaxy types that possess prominent disks. These include spiral galaxies (Hubble Types Sa-d and Sm) and S0 galaxies (otherwise known as lenticular galaxies).
Disk galaxys are one of the two main types of galaxy observed in the universe, the other type being elliptical galaxies. We live in a disk galaxy called the Milky Way, it is a spiral disk galaxy.
Definition: disk: The visible surface of the sun or any other heavenly body projected against the sky.
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Airy disk
The central spot in the diffraction pattern of the image of a star at the focus of a telescope, named after George Airy. It is surrounded by several fine diffraction rings like the rings around the bull's-eye of a target.
Dust Disk
NASA, JPL, University of Florida
Larger false-color and black and white images.
Disk galaxies are thus rather fragile and delicate objects. The evidence, while fragmentary and largely circumstantial, suggests that these galaxies grow best in quiet, ...
Full Disk Neptune
On its approach to in August 1989, Voyager 2 captured this image of the fourth and outermost of the giant gas planets. This image shows two of the four oval cloud features tracked by the cameras.
Accretion Disk :
The center of active galaxies is the site of a wide range of activity apparently powered by the black hole. X-rays and gamma-rays are emitted from the area, and rapidly moving gas clouds can be observed there.
Dynamics in Disk Galaxies
A detailed understanding of the internal working of galaxies must incorporate their dynamics - just how the gravitational potential and internal motions balance to give galaxies their forms.
Accretion disk
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An accretion disk is a structure that is created when matter falls into a gravitational source, like a wormhole.
A protoplanetary disk (or proplyd) is a rotating disk of dense gas surrounding a young newly formed star, a T Tauri star or Herbig star.
Protoplanetary disk
A proplyd forming in the Orion Nebula.
The protoplanetary disk HH-30 in Taurus, about 450 light years away. The disk emits the reddish stellar jet, a common structure of these formations.
disk--The surface of the Sun as it is seen in the sky
electric field--The forces in action between two charged objects
filament--A mass of gas that appears as dark lines suspended over the photosphere by magnetic fields ...
Disk. The visible surface of the Sun (or any heavenly body) projected against the sky.
Disk Component
All material confined to the plane of the galaxy.
Distance Indicator ...
Disk
the surface of the Sun or other celestial body projected against the sky.
Disk Instability - A possible explanation for the origin of a close binary pair of stars in which one star forms within the disk of gas and dust orbiting another, newly formed star ...
Disk. The appearance or face of a planet, star or moon as seen from Earth.
Diurnal. Another name for daily.
Disk
The central plane of a galaxy, as distinguished from other structural and mprphological components such as its bulge, halo or nucleus.
Airy Disk - The Airy Disk is a disk of light from a star that forms at the focal plane of an optical system instead of a point. The stars we see in the night sky are so far away that they are essentially point sources.
THIN DISK - The defining morphological component of disk galaxies in general and spiral galaxies in particular. The thin disk contains stars, star clusters, gas and dust confined to the galaxy's plane of rotation.
thick disk Region of a spiral galaxy where an intermediate population of stars resides, younger than the halo stars, but older than stars in the disk.
seeing disk Roughly circular region on a detector over which a star's pointlike images is spread, due to atmospheric turbulence.
seismic wave A wave that travels outward from the site of an earthquake through the Earth.
A cipher disk is an enciphering and deciphering tool developed in the 15th century by Leon Battista Alberti.
Disk rotates :
Sun's speed ~220 km/s
Sun's orbital period ~200 million yrs
about 50 rotations since birth of galaxy
Kepler's law ---
M ~ 10 11Msun inside of Sun's orbit ...
disk
(a) A flattened, circular region of gas, dust, and/or stars. It may refer to material surrounding a newly-formed star; material accreting onto a black hole or ; or the large region of a spiral galaxy containing the spiral arms.
Disk sometimes sharply defined; diffraction rings seen as long arcs or complete circles.
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Disk always sharply defined; rings seen as long arcs or complete circles, but always in motion.
disk - (n.)
(a.) Of a galaxy, the disk-like flat portion, as opposed to the nucleus or the halo; (b) Of a star or planet, the two-dimensional projection of its surface.
distance modulus - (n.) ...
A disk of gas and dust glows softly in this artist's concept of the star system known as HD 97048. The disk contains enough gas to make about 10 Jupiter-sized planets and enough solid particles to make 50 planets as massive as Earth.
A disk of dust and gas encircles the star with a tilt of 30 degrees and the planet shares this orientation. This is direct evidence for the formation of planets from disks of this kind, which are seen around many other young stars.
a disk surrounding a black hole or star in which matter gravitationally falls onto the central object
achromatic lens
a two-element lens, or doublet, that significantly reduces chromatic aberration ...
No disk. Stars smoothly distributed through an ellipsoidal volume ranging from nearly spherical (E0) to very flattened (E7) in shape. No obvious substructure other than a dense central nucleus.
Stellar content ...
The disk is surrounded by a spheroid halo of old stars and globular clusters. While the disk contains gas and dust obscuring the view in some wavelengths, the halo does not.
The disk defines the orbital plane of the youngest stars in the galaxy. The disk is much thinner than its diameter. The orbits are nearly circular around the center of the Galaxy.
The disk includes solutions to the problems and is distributed with the understanding that such solutions will only be available to teachers.
Questions from Users: Advice to home-schooling parent
Timeline Glossary Math index ...
Some disk galaxies have no spiral arms and are called ``S0'' (``SB0'' if there is a bar) or lenticular galaxies. They are placed at the point in the tuning fork diagram where it brances off to the regular spiral or barred spiral pattern prong.
Thin disk around Beta Pictoris. [more]
HD 141569: Gap in stellar dust disk. [more]
HR 4796A: Dust ring around star. [more] ...
Huge Disk Galaxy
(117K GIF)
This is the Andromeda Galaxy, our nearest large neighbor galaxy.
(86K GIF) ...
Full-disk mosaic of the million-degree Sun by TRACE
Due to the high spatial (1 arc second) and temporal resolution (1-5sec), TRACE has been able to capture highly detailed images of coronal structures, ...
Galactic Disk
A flattened disk of gas and young stars in a galaxy. Some galactic disks have material concentrated in spiral arms (as in a spiral galaxy) or bars (as in barred spirals).
Galactic Halo ...
Accretion Disk
A relatively flat, rapidly rotating disk of gas surrounding a black hole, a newborn star, or any massive object that attracts and swallows matter.
accretion disk
The whirling disk of gas that form around a compact object such as a white dwarf, neutron star or black hole as matter is drawn in.
active galactic nuclei (AGN) ...
ACCRETION DISK
An accretion disk is a flat disk of gas and dust in space that surrounds a newborn star, black hole, or other enormous object that is growing by attracting matter to it with its gravitational field.
Accretion Disk: A disk of gas that accumulates around a center of gravitational attraction, such as a white dwarf, a neutron star, or a black hole.
The compass disk represents a part of the surface of the Earth. You can imagine a tiny observer (standing on the black dot at the center of the disk) looking out at the horizon in any direction. The round head of the paper fastener represents the Sun.
Discovered a disk of dust grains around the star Vega
Detected disks of material around several other stars.
Detected several probable protostars embedded in clouds of gas and dust ...
We live in a disk-shaped Galaxy of some 200 billion stars that we see around us as the broad white band of the Milky Way.
The original disk. There was a sizeable amount of rocky metallic matter left in the dusty chaos after the Sun formed. And tiny particles of frozen water and frozen carbon dioxide. All were suffused through a vast cloud of hydrogen and helium.
A. Is the Airy disk clearly visible, even though highly mobile and sometimes merged with background light?
" NO: Go to B.
" YES: Go to C.
burst disk (NASA SP-7, 1965) A diaphragm designed to burst at a predetermined pressure differential; sometimes used as a valve, e.g., in a liquid propellant line in a rocket. Also called a rupture disk .
disk
The flattened structure of a circular collection of material, which often refers to the overall structure of a spiral galaxy.
a central, flat disk containing a dense cloud of interstellar matter and young star clusters (mostly on the arms) a central bulge (or nucleus) containing older stars ...
*Uranus' apparent disk size, on the other hand, is only one-sixteenth as large Venus'. To find the proportionate disk size, you always square the diameter (1/4 X 1/4 = 1/16). copyright 2004 by Bruce McClure
Mercury in the Morning ...
Galaxy A large disk or ball of billions of stars and nebulae. They are the largest individual structures in the Universe.
mater: the heavy disk which forms the base of an astrolabe.
mean solar day: the time between successive transits of the fictitious mean Sun (i.e.
Obtain an acrylic disk, about 12 inches or 30 cm in diameter and 1/8 inch or 3 mm thick. Attach the acrylic disk's center to the motor shaft.
aneroid (NASA SP-7, 1965) A thin, disk-shaped box or capsule, usually metallic, partially evacuated of air and sealed, which expands and contracts with changes in atmospheric or gaseous pressure.
An ACTIVE PROMINENCE seen on the DISK. ACTIVE LONGITUDE. The approximate center of a range of heliographic longitudes in which ACTIVE REGIONS are more numerous and more FLARE-active than the average. ACTIVE PROMINENCE.
coronagraph a special instrument which blocks light from the disk of the Sun in order to study the faint solar atmosphere. cosmic ray an extremely energetic (relativistic) charged particle.
Open clusters are also known as galactic clusters as they are generally located along the disk of spiral galaxies where star formation is more common. Open clusters have a few dozen up to a few thousand stars in a vloume up to 20 parsecs or so wide.
 See also: Light, Sun, Solar, Earth, Star
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