Astronomical Terms & Definitions

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Astronomical Terms & Definitions

Albedo:

In astronomy, the term albedo refers to the brightness of an object in space. Derived from Latin, albedo means “whiteness” (albus= “white”). Albedo is measured on a scale from 0 to 1, where 0 refers to an object that’s completely dark, i.e., it doesn’t reflect any light. 1 on the size refers to a wonderfully reflective object. The Moon has an Albedo of 0.12, while Earth’s average albedo is 0.3.

Altitude (elevation):

Altitude or elevation is that the angle an object makes with the horizon.

Annular Solar Eclipse:

An annular eclipse happens when the Moon covers the Sun’s center, leaving the Sun’s visible outer edges to make a “ring of fire” or annulus round the Moon.

Antumbra:

The antumbra is that the lighter a part of a shadow that forms at a particular distance from the thing casting the shadow. it’s involved in annular solar eclipses and planet transits.

Asterism:

A pattern of stars recognizable to observers from Earth. Asterisms may or might not be a part of a constellation. the large Dipper is one among the foremost well-known asterisms. Its stars belong to the constellation Great Bear .

Asteroid:

These are found between the orbits of Mars and Jupiter. These are celestial bodies with sizes starting from a couple of meters to many the kilometres of diameter, revolving round the sun. they need originated by the disintegration of the planets.

Astronomical Season:

Astronomers and scientists use the dates of equinoxes and solstices to mark the start and end of seasons during a year. within the hemisphere , the four astronomical seasons are:

Spring:

vernal equinox to June solstice.

Summer:

June solstice to autumnal equinox .

Fall (autumn):

autumnal equinox to December solstice.

Winter:

December solstice to vernal equinox .

Astronomical Twilight:

Astronomical twilight is that the darkest of the three twilight phases. it’s the earliest stage of dawn within the morning and therefore the last stage of dusk within the evening.

Astronomical Unit:

the typical distance between Earth and therefore the Sun, 1.5 x 108 km

Atmospheric Phenomena:

Atmospheric phenomena occur when light, usually from a natural source, but sometimes from artificial sources, is reflected or refracted because it passes through the atmosphere, for instance by air molecules, ice crystals, or differing types of particles.

Aurora:

The glowing light from solar particles interact with Earth’s magnetic flux is named aurora

Aurora Borealis and Aurora Australis:

An aurora may be a phenomenon that makes bright and colorful light displays within the sky. within the Arctic Circle , they’re referred to as northern lights or northern lights; within the Antarctic Circle , they’re called aurora australis or southern lights.

Axial Tilt – Obliquity:

Earth’s axis is tilted by about 23.4 degrees to the perpendicular to the plane . Earth rotates the Sun at a slant. this suggests that different amounts of sunlight reach the Northern and Southern Hemispheres throughout the year. this is often the rationale we’ve seasons on Earth.

Axis:

An axis in astronomy refers to the (imaginary) line that an object, usually a planet, rotates around. Earth’s rotational axis is an imaginary line that runs through the North and South Poles

Azimuth:

An object’s cardinal direction, like north, east, south, or west

Black Hole:

A star remains contracting and, thus, mass during a great quantity , concentrates on one point. Such body with high density is named region . It doesn’t allow anything to flee , including the sunshine thanks to which it are often seen. it’s John Wheeler who propounded the concept of region

Black Moon:

It are often the third new phase of the moon in an astronomical season with four new phase of the moon s or the second New Moon within the same month .

Two Definitions of Blue Moon:

Seasonal long time = The third full-of-the-moon in an astronomical season with four Full Moons (versus the standard three).

Monthly long time = The second full-of-the-moon during a month with two Full Moons.

If the moon actually looks blue, it’s caused by a rare sort of dust within the atmosphere.

Celestial Equator:

The equinoctial circle is that the projection of Earth’s equator onto the sphere . From our perspective, it’s the a part of the sky directly above the equator.

Celestial Horizon:

The imaginary horizontal line separating the 2 hemispheres of the sphere is named the horizon .

Celestial Pole:

The celestial poles are imaginary lines that trace Earth’s rotation axis in space. From our perspective, they’re the points within the sky directly above the North Pole and therefore the South Pole . due to this, objects that lie on the pole don’t seem to maneuver in the least , while all other objects, mostly stars, seem to maneuver during a revolve around the pole.

Celestial Sphere:

The sphere is an imaginary sphere that extends infinitely into space with Earth at its center. it’s the backdrop the horizontal frame of reference uses to map the sky and describe the positions of its objects.

Circumpolar Stars:

Circumpolar stars never set or go below the horizon for observers from specific latitudes. they’re visible to observers from these latitudes throughout the year due to their proximity to the pole . Circumpolar objects lie within the circumpolar circle, and stars circumpolar to latitudes within the hemisphere aren’t visible within the hemisphere , and the other way around .

Civil Twilight:

Civil twilight is that the brightest of the three twilight phases. The Sun is simply below the horizon, so there’s generally enough natural light to hold out most outdoor activities.

Comet:

one among the tiny , icy bodies that orbit the sun that make tails of gas and mud once they get on the brink of the sun. There are the bodies composed of dust, ice and gases, which come from the colder and darker areas, faraway from the sun. they are going round the sun in large and irregular orbits. While occupation their orbits, once they come very on the brink of the sun, they begin glowing with a bright gaseous tail always pointing faraway from the sun. many an times, comets are visible to the eye and present a really spectacular sight. Comet Halley, discovered by Halley , returns after every 76 years

Constellation:

within the present day, a constellation may be a two-dimensional area in space as defined by the International Astronomical Union (IAU). Today, there are 88 officially recognized constellations. this is often different from the historical understanding of a constellation dominantly utilized in astrology which is defined as a gaggle of stars easily identifiable by a pattern to observers on Earth.

Crust:

The land and oceans at the Earth’s surface lie on an outer layer of cool, hard rock called the crust.

Core:

At the very centre of the world may be a super-hot ball of iron called the core

Dawn:

Dawn is that the transition from night to day because the sky gets brighter. Scientists distinguish between three definitions of dawn: civil, nautical, and astronomical dawn. all may be a specific moment in time, supported the solar elevation angle.

Dusk:

Dusk generally refers to the transition from day to nighttime . Scientists distinguish between three definitions of dusk: civil, nautical, and astronomical dusk. all may be a specific moment in time, supported the solar elevation angle.

Diamond Ring:

Just before the moon completely covers the sun, mountains on the moon allow a touch of sunshine to peek through creating this beautiful diamond ring effect at right

Eight planets:

system consists of eight “planets” Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Ecliptic:

the trail the Sun seems to follow within the sky

Earthshine:

Earthshine may be a dull glow which sometimes lights up the unlit a part of the Moon. it always occurs a couple of days before and after a replacement Moon when sunlight reflects off surface and illuminates the portion of the Moon’s surface which isn’t lit up by direct sunlight.

Eclipses:

A eclipse happens when the new phase of the moon moves between Earth and therefore the Sun. A eclipse occurs when Earth casts a shadow onto the complete Moon.

Ecliptic — Ecliptic Plane – Orbital Plane:

The ecliptic plane, also called plane , is that the imaginary line that traces the Sun’s apparent path within the sky. In other words, it’s the projection of our planet’s orbit into the sphere . Any constellations on this line are referred to as zodiacal or zodiac constellations.

Earth’s Axial Tilt or Obliquity:

When an object the dimensions of Mars crashed into the newly formed planet Earth around 4.5 billion years ago, it knocked our planet over and left it tilted at an angle.

Elevation (altitude):

Elevation or altitude is that the angle an object makes with the horizon.

Equinox:

There are two equinoxes per annum – in March and September – when the Sun is directly above the equator and therefore the length of night and day are nearly equal.

False Dawn:

False dawn or reflection may be a rare physical phenomenon that happens around sunset and sunrise, usually during early spring and late fall.

Full Moon:

the complete Moon is that the Moon phase when the whole face of the Moon is lit up.

Great Circle:

an excellent circle is any circle that’s formed by a plane that passes through the middle of Earth. The equator and therefore the circles created by the meridians form great circles.

Halos:

Halos are atmospheric phenomena created by light which is reflected or refracted by ice crystals within the atmosphere.

Horizontal Coordinate System:

The horizontal frame of reference , also referred to as the Alt/Az system, may be a method for describing the precise position of objects within the sky, like planets, the Sun, or the Moon.

Light Pillars:

Light Pillars are an physical phenomenon created by light which is reflected by ice crystals within the atmosphere.

Light Year:

a light-weight year (also spelled: light-year or lightyear) may be a unit of distance and is defined because the distance traveled by light during a vacuum during a Julian year. In astronomy, a Julian year (symbol: a) may be a unit of time defined as exactly 365.25 days of 86,400 seconds each. the space is approximately 9.5 trillion kilometers or 6 trillion miles.

Local Midnight:

Local midnight typically occurs when the Sun crosses the meridian below the horizon. In areas where there’s atmospheric phenomenon , local midnight is when the Sun is at its lowest point of the night.

Lunar Apogee:

the purpose of the Moon’s orbit farthest from Earth is named apogee.

Lunar Month:

A moon is that the time it takes the Moon to undergo all of the Moon phases, measured from one new phase of the moon to subsequent . A moon is additionally referred to as a lunation, while the astronomical term for this era may be a lunar month .

Lunar Perigee:

the purpose of the Moon’s orbit closest to Earth is named perigee.

Lunation:

A lunation is that the time it takes the Moon to undergo all of the Moon phases, measured from a replacement Moon to subsequent new phase of the moon . A lunation is additionally referred to as a moon , while the astronomical term for this era may be a lunar month . Lunations are numbered in several different systems; the foremost common one is that the Brown lunation numeration system , which we use our Moon phase pages.

Magnetic Declination:

The difference between true north and north is named magnetic declination or magnetic variation.

Meridian:

A meridian is an imaginary line that runs from the North Pole to the South Pole , connecting all locations sharing an equivalent longitude. the moment when the Sun or the Moon crosses a location’s meridian marks the instant once they reach the very best position within the sky, appearing either south , due north, or directly overhead. For the Sun, it’s the instant of solar noon.

Meteor:

When a meteoroid enters Earth’s atmosphere, it starts to glow because it collides with air molecules within the upper atmosphere. The flash of sunshine this generates is named a meteor, a meteor , or a falling star. Meteors are the celestial bodies composed of dust and gases. After coming under the influence of earth’s gravity, they move with an excellent velocity towards the world . But, thanks to collision with the particles of the atmosphere they burn and obtain converted into ash.

Meteor Shower:

A meteor stream is when an unusual amount of meteors—or shooting stars—flash across the night sky over a period, usually a couple of days or weeks.

Meteorite:

A meteorite is that the name for an area rock or meteoroid which has survived falling through the atmosphere and has landed on Earth.

Meteoroid:

Meteors which are large in size and don’t burn completely and reach the surface of the world are called meteorites. A meteoroid may be a block of matter made from dust particles or fragments from a comet or an asteroid. Meteoroids become meteors, also called shooting stars, once they enter Earth’s atmosphere burning a trail of dust and fire which is visible from Earth as a flash of sunshine within the sky.

Micromoon:

When a full-of-the-moon or a replacement Moon occurs around apogee, which is that the point on the orbit farthest from Earth, it’s called a Micromoon, Minimoon, or Apogee Moon. When there’s a Full or new phase of the moon around perigee, it’s called a Supermoon.

Midnight Sun — Polar Day:

Midnight Sun is when a minimum of a neighborhood of the Sun’s disk is visible above the horizon 24 hours of the day. The scientific name for atmospheric phenomenon is polar day, and therefore the opposite is polar night.

Moon Phase:

The sunlight that reflects onto the Moon’s surface we call a Moon phase. what proportion of that light we will see from our point of view on Earth varies a day . The moon is usually divided into four primary and 4 intermediate Moon phases: new phase of the moon , Waxing Crescent Moon, half-moon Moon, Waxing Gibbous Moon, Full Moon, Waning Gibbous Moon, Third Quarter Moon and Waning Crescent Moon

Moonbows:

Moonbows or lunar rainbows are rare natural atmospheric phenomena that occur when the Moon’s light is reflected and refracted off water droplets within the air.

Moonrise and Moonset:

Moonrise is defined because the moment the upper fringe of the Moon becomes visible above the horizon. The Moon sets because the upper edge disappears below the horizon. Sometimes, the Moon isn’t visible albeit it’s above the horizon. this is often the case, for instance , during the new phase of the moon and when the sky isn’t clear.

Magma:

Inside the centre of the world there’s red-hot, liquid rock. This rock is named magma.

Mantle:

the recent magma below rises and sinks slowly during a layer called the mantle.

Neutron Star:

If the mass of the star is far quite the mass of the sun then it became star .

Nautical Twilight:

Nautical twilight is that the second twilight phase. Both the horizon and therefore the brighter stars are usually visible at this point , making it possible to navigate stumped .

Northern Lights — Aurora Borealis:

An aurora may be a phenomenon that makes bright and colorful light displays within the sky. within the Arctic Circle , they’re referred to as aurora borealis or northern lights.

Obliquity – Axial tilt:

Earth’s axis is tilted about 23.4 degrees to the perpendicular to the plane . Our planet rotates the Sun at a slant. this suggests that different amounts of sunlight reach the Northern and Southern Hemispheres throughout the year. this is often the rationale we’ve seasons on Earth.

Orbit:

An orbit is that the path of an object around some extent or another object in space. generally , this path is repeatedly followed by the thing , though, in some cases, different celestial forces like gravitation can change its orbit. An object in orbit is named a satellite. Orbits are formed thanks to two opposing forces—the orbiting object’s momentum and therefore the force of gravity that pulls it towards the thing it’s orbiting. These two forces need to balance one another for an orbit to be sustained.

Parhelic Circle:

A solar halo may be a rare optical physical phenomenon .

Partial Lunar Eclipse:

A partial eclipse occurs when Earth moves between the Sun and Moon, but the three bodies don’t form a wonderfully line in space. When this happens, only a part of “> a part of the Moon’s surface is roofed by the darkest part of the shadow cast by Earth, the umbra.

Partial Solar Eclipse:

During a partial eclipse , only a part of the solar disk is roofed by the new phase of the moon .

Penumbra:

The penumbra is that the lighter outer a part of a shadow. The Moon’s penumbra causes partial solar eclipses, and Earth’s penumbra is involved in penumbral lunar eclipses.

Penumbral Lunar Eclipse:

A penumbral eclipse occurs when the Sun, Earth, and therefore the Moon align in an almost line . When this happens, Earth covers all or a part of “> a part of the Moon with the outer part of its shadow, also referred to as the penumbra. Since the penumbra is far fainter than the dark core of the Earth’s shadow, the umbra, a penumbral eclipse of the Moon is usually difficult to inform aside from a traditional full-of-the-moon .

Pink Moon:

the complete Moon in April is that the Pink Moon, from the pink flowers – phlox – that bloom within the early spring.

Plates:

The earth’s surface is cracked into large pieces, called plates, which fit together like a huge jigsaw. There are nine large plates and a number of other smaller ones.

Planetary Transit:

A planetary transit occurs when a planet passes ahead of the Sun. it’s then visible from Earth as a small black dot silhouetted against the Sun’s disk. the sole two planets which will be seen transiting the Sun from Earth are Mercury and Venus, because they’re the sole planets inside Earth’s orbit.

Polar Day — atmospheric phenomenon :

Polar day or Midnight Sun is when a minimum of a neighborhood of the Sun’s disk is visible above the horizon 24 hours of the day. The scientific name for atmospheric phenomenon is polar day, and therefore the opposite is polar night.

Polar Night:

Polar night happens when the whole Sun remains below the horizon all day. It only happens within the latitude , and therefore the opposite of polar night is atmospheric phenomenon or polar day.

Reflection:

Reflection occurs when light bounces off the surface of an object.

Refraction:

Refraction is that the bending of sunshine because it moves from one substance to a different . for instance , it happens when sunlight enters Earth’s atmosphere.

Shooting Star:

A meteor may be a popular term for a meteor, which may be a flash of sunshine generated when a meteoroid enters Earth’s atmosphere.

Solar Day:

Modern timekeeping defines each day because the sum of 24 hours – but that’s almost correct. In solar time, most days are a touch longer than 24 hours, the time it takes from one solar noon to subsequent .

Solar Noon:

Solar noon occurs when the Sun crosses a location’s meridian and reaches its highest position of the day. In most locations, it doesn’t happen at 12 o’clock. Find Sun times worldwide.

Solar Time:

A sundial shows truth or apparent solar time. Because Earth’s rotation isn’t constant, solar days vary slightly long . this suggests that the speed of true solar time isn’t constant. Mean Solar Time is predicated on the length of a mean or average day , which is 24 hours long. It moves at a continuing speed.

Solar Wind:

solar radiation is a component of space weather. it’s endless stream of highly energized particles – mostly electrons and protons – that effuse from the Sun through space at very high speeds and heat . aurora borealis are caused by high solar radiation activity.

Solstice:

Solstices happen twice a year — in June and December. The June solstice is around summer solstice , when the Sun is directly overhead the Tropic of Cancer. The December solstice takes place around December 21. On today , the Sun is precisely over the Tropic of Capricorn. The solstice is that the shortest day of the year, while the June 21 is that the longest day of the year. Solstices are opposite on either side of the equator.

Southern Lights — Aurora Australis:

An aurora may be a phenomenon that makes bright and colorful light displays within the sky. within the Antarctic Circle , they’re called aurora australis or southern lights.

Summer Solstice:

The June 21 is that the longest day of the year. Solstices are opposite on either side of the equator; the June 21 within the hemisphere is that the June solstice, while within the hemisphere , it’s the December solstice.

Sundogs:

Sundogs are an physical phenomenon created by light which is reflected or refracted by ice crystals within the atmosphere.

Sunspots:

Sunspots are areas where the cooler areas show up darker than the encompassing surface. Some sunspots are larger than the diameter of the world and may reach up to twenty ,000 km in diameter.

Solar flares:

Solar flares are jets of particles that burst from the sun and may disrupt satellite communications and knock out electricity on Earth. Solar flares can sometimes leave the sun and zoom towards Earth. When the high speed particles from the sun contact the Earth’s magnetic flux it produces a lighting effect referred to as the aurora.

Supernova:

The helium starts converting into carbon and carbon into heavy metal like iron within the core. This leads to a huge explosion within the which is understood as supernova

Sunrise:

Sunrise is defined because the moment the upper fringe of the solar disk—called the upper limb—becomes visible above the horizon.

Sunset: because the upper fringe of the solar disk—called the upper limb—disappears below the horizon, the Sun has set.

Supermoon:

When a full-of-the-moon or a replacement Moon occurs around perigee, which is that the point on the orbit closest to Earth, it’s called a Supermoon. When a full-of-the-moon takes place when the Moon is near its closest approach to Earth, it’s called an excellent full-of-the-moon . When there’s a replacement Moon round the closest point to Earth, it’s referred to as an excellent new phase of the moon .

Synodic Month:

A lunar month is that the time it takes the Moon to undergo all of the Moon phases, measured from a replacement Moon to subsequent new phase of the moon . it’s also referred to as a moon or a lunation.

Tides:

The gravitational pull of the Moon and therefore the Sun makes the water within the oceans bulge, causing endless change between high and low water .

Total Solar Eclipse:

During a complete eclipse of the Sun, the Moon covers the whole disk of the Sun. a complete eclipse is merely total within the trail of totality and just for a brief while. Most of the time and in most places, it’s visible as a partial eclipse .

Tropical Year:

A solar year is that the time it takes Earth to finish a full orbit round the Sun. Its duration varies from year to year. Also referred to as a tropical year , an solar year , or an solar year , it is, on the average , approximately three hundred and sixty five days , 5 hours, 48 minutes and 45 seconds long (365.24219 days).

Twilight:

Twilight is that the time between day and night when there’s light outside, but the Sun is below the horizon. There are three degrees of twilight: civil, nautical, and astronomical twilight.

Umbra:

The umbra is that the darkest portion of a shadow. The Moon’s umbra causes total solar eclipses, while Earth’s umbra sometimes creates total and partial lunar eclipses.

Zenith:

In celestial coordinate systems, the situation straight above you is named zenith while the purpose exactly below you is mentioned as nadir.

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