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Astronomy Topics - Absolute Brightness
- The total luminosity radiated by an object.
- Absorption Edges
- Sudden rises superposed on the smooth decrease of the curve of the attenuation coefficient, which cause the curve to have a typical sawtooth aspect.
- Absorption Lines
- Dark lines in a spectrum that are produced when light or other electromagnetic radiation passes through a gas cloud or similar object closer to the observer.
- Absorption Trough
- Range of wavelengths at which atomic hydrogen absorbs or emits radiation.
- Accretion
- The process by which the terrestrial planets grew.
- Accumulation Theory
- The theory by which planetesimals are assumed to collide with one another and coalesce, eventually sweeping up enough material to form the planets.
- Active Sun
- The Sun during its 11-year cycle of activity when spots, flares, prominences, and variations in radio frequency radiation are at a maximum.
- Adaptive Optics
- A technique that uses deformable mirrors on a telescope to correct the blurring caused by turbulence in the atmosphere.
- Apocentre
- The point on a spacecraft′s orbit at which it is furthest away from the body it is orbiting.
- Astrometry
- The branch of astronomy concerned with measuring the positions of celestial bodies, such as stars and galaxies, and their real and apparent motions.
- Astronaut
- A person who rides in a space vehicle.
- Aurora Australis
- The aurora of the Southern Hemisphere.
- Auroral Oval
- The region in which aurora appears at the same time, corresponding to the ring of fire around the magnetic pole.
- Binary Star
- Pair of stars bound together by mutual gravitation and orbiting their common centre of mass.
- Black Hole
- A massive star that has collapsed to such a small size that its gravitational force is so strong that not even light can escape from its 'surface'.
- Blue Supergiant
- A supergiant star with spectral type O or B.
- Bow Shock
- The shock wave caused by the edge our Solar System travelling through deep space.
- Brahe, Tycho
- Danish astronomer who made precise observations of the sky.
- Carbonado
- Carbon that has metamorphosed into its diamond phase but remains black.
- Cassegrain Telescope
- Two-mirror reflecting telescope.
- Cataclysmic Variable
- A binary star system containing a white dwarf that exhibits sudden outbursts of energy.
- Celestial Sphere
- An imaginary sphere of infinite radius centered on the Earth and poles aligned with the poles of the Earth.
- Chemical Enrichment
- The process in which a star manufactures chemical elements, such as carbon and oxygen, in the nuclear reactions in its interior and then ejects these elements into space.
- Decaying Orbit
- An unstable orbit from which the orbiting object will gradually spiral into the body it is orbiting.
- Earth
- The basic Earth data.
- Evening Star
- Name given to Venus when observed in the evening, also known as Phosphorus.
- Faculae
- Bright granular structures on the surface of the Sun that are slightly hotter than the surrounding photosphere.
- Faint Young Sun Paradox
- Calculations suggest that at about the time of the formation of Earth, the Sun was roughly two-thirds the brightness that it is now. However, there is no geological evidence.
- Galaxy Clusters
- Groups of galaxies that may contain up to a few thousand galaxies.
- Great Year
- Or Platonic Year, the period of one complete cycle of the equinoxes around the ecliptic, about 25800 years.
- Heliopause
- The boundary between the solar wind and the interstellar wind, where the pressure of both are in balance.
- Heliosheath
- A vast, turbulent expanse where the solar wind piles up as it presses outward against interstellar matter.
- Jupiter
- The largest planet in our solar system.
- Keplers Laws
- Kepler found three laws defining the orbit of planets.
- Kerr Black Hole
- A rotating black hole.
- Lunar Eclipse
- When the Moon enters the Earth′s shadow as the Earth moves between the Sun and the Moon.
- ly
- Abbreviation of Light Year.
- Mars
- The fourth planet from the sun in our solar system.
- Mercury
- The planet nearest to the sun in our solar system.
- Meteor
- A meteoroid that has entered Earth′s atmosphere.
- Meteorite
- The remnants of a meteor after it has actually impacted the Earth.
- Meteoroid
- An object in space similar to but smaller than an asteroid.
- Moon
- Basic Moon data.
- Morning Star
- Name given to Venus when observed in the morning, also known as Hosperus.
- Neptune
- The outermost gas giant in our solar system.
- Neutron Star
- A star composed only of neutrons.
- North Pole
- That end of the axis of rotation of a celestial body at which, when viewed from above, the body appears to rotate in a counter-clockwise direction.
- Nova
- A star which suddenly becomes many times brighter than previously, and then gradually fades.
- Opposition
- The point at which a planet that is further away from the Sun than the Earth.
- Orbit Acquisition
- Reception of the telemetry containing the information about the orbital parameters of the spacecraft.
- Planet
- A spherical ball of rock and/or gas that orbits a star.
- Platonic Year
- The period of one complete cycle of the equinoxes around the ecliptic, about 25800 years.
- Pluto
- The outermost planet in our solar system and it′s double Charon.
- Protoplanet
- Any of the sun′s planets as it emerged or existed in the formative period of the solar system.
- Protoplanetary Disc
- The disc of dust surrounding a star out of which planets might form.
- Protosun
- The sun as it emerged in the formation of the solar system.
- Pulsar
- A stellar source, such as a rotating single star or pair of stars, emitting electromagnetic radiation which is characterised by rapid frequency and regularity.
- Red Supergiant
- A supergiant with spectral type M. These are the largest stars in the universe.
- Reflecting Telescope
- A type of telescope using a mirror as the objective.
- Refracting Telescope
- A type of telescope using a lens as the objective.
- Satellite
- An object in an orbit around a planet.
- Saturn
- The sixth planet from the sun in our solar system.
- Schwarzschild Black Hole
- A nonrotating, spherical black hole that has no electric charge.
- Solar Eclipse
- When the Earth enters the Moon′s shadow as the Moon moves wholly or partially in front of the Sun as seen from Earth.
- Standing Wave
- The interference pattern produced by two waves of equal amplitude and frequency traveling in opposite directions.
- Star
- A ball of mostly hydrogen and helium gas that shines extremely brightly. Our Sun is a star.
- Starburst Galaxy
- Galaxy in which a large burst of star formation is observed.
- Stellar
- Of the stars.
- Stellar Wind
- A steady or unsteady outflow of material from the surface of a star.
- Sun
- The star at the centre of our solar system.
- Sunspot
- An area on the surface of the sun marked by a lower temperature than its surroundings and that has magnetic activity.
- Telescope
- Instrument used to focus electromagnetic radiation into an image.
- Termination Shock
- Particles from the Sun begin to slow and clash with matter from the sparse gas found between the stars.
- True Sun
- The actual sun as it appears in the sky.
- Uranus
- The seventh planet from the sun in our solar system.
- Yellow Supergiant
- A supergiant star with a spectral type of G.
- Zenith Telescope
- Instrument for observing stars near the zenith.
See also: Astrophysics.
  
Subjects:- Physics
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