Different Celestial Bodies and Natural Phenomena.

Galaxy:

A galaxy is defined as a huge congregation of stars which are held together by the force of gravity. Galaxies numbering millions lie scattered in the Universe like dots. The galaxies are the clusters of stars. These can be spiral galaxies, elliptical galaxies or irregular galaxies. Out of these, the spiral galaxies are large flattened systems with spiral arms extending outwards from a central nucleus. The Elliptical galaxies have not internal structure and are spherical. The largest ellipticals, exceeds from 1012 solar masses. The irregular galaxies have no particular shape but possess large amount of interstellar matters.

Milky Way is a spiral galaxy to which the Sun belongs. It comprises of hundred of thousand million stars. It has a flattened disc which is 120 light years across where as the distance of the Sun from the center is 3,300 light years. Two spiral arms wind out from bulging central nucleus. Black hole exist in the center of Galaxy. A black hole is a region of greatly distorted space, size of which increase with the mass of contracting material. In 2004, the Hubble Space Telescope discovered a new galaxy Abell which is about 13,230 million light years away from the Earth. We belong to galaxy Milky Way, which is a part of a cluster of three dozen galaxies called the local group. The Milky Way is the second largest galaxy of the local group followed by Andromeda Galaxy. The distance from Andromeda galaxy to Milky way is 2 million light years. Apart from Andromeda and Milky way the some of the galaxies of Local Group are:

  • Triangulum Galaxy

The Triangulum Galaxy is a spiral galaxy 2.73 million light-years from Earth in the constellation Triangulum. It is catalogued as Messier 33 or NGC 598. The Triangulum Galaxy is the third-largest member of the Local Group of galaxies, behind the Milky Way and the Andromeda Galaxy.

  • Large Megellanic Cloud

 It is 158,200 light years distant from the Earth.  Its diameter is 7,000 light years

Apparent size (V): 10.75° × 9.17°

The Large Magellanic Cloud is a satellite galaxy of the Milky Way. At a distance of around 50 kiloparsecs, the LMC is the second- or third-closest galaxy to the Milky Way, after the Sagittarius Dwarf Spheroidal and the possible dwarf irregular galaxy known as the Canis Major Overdensity.

  • Messier 32

Messier 32 is a dwarf “early-type” galaxy located about 2.65 million light-years from Earth, appearing in the constellation Andromeda. M32 is a satellite galaxy of the Andromeda Galaxy and was discovered by Guillaume Le Gentil in 1749. M32 measures 6.5 ± 0.2 thousand light-years in diameter at the widest point.

Radius: 3,250 light years

Distance to Earth: 2.489 million light years

Apparent mass: ~3 billion M☉

Magnitude: 8.1

Constellation: Andromeda

Apparent size (V): 8′.7 × 6′.5

  • Small Magellanic Cloud

The Small Magellanic Cloud, or Nubecula Minor, is a dwarf galaxy near the Milky Way. Classified as a dwarf irregular galaxy, the SMC has a diameter of about 7,000 light-years, contains several hundred million stars, and has a total mass of approximately 7 billion solar masses. 

Distance to Earth: 199,000 light years

Radius: 3,500 light years

Apparent mass: ~6.5 billion M☉

Distance: 201±6 kly (61.7±2.0 kpc)

Apparent size (V): 5° 20′ × 3° 5′

Coordinates: RA 0h 52m 45s | Dec -72° 49′ 43″

  • Messier 110

Messier 110, or M110, also known as NGC 205, is a dwarf elliptical galaxy that is a satellite of the Andromeda Galaxy. 

Distance to Earth: 2.674 million light years

Radius: 8,500 light years

Apparent mass: ~9.3 billion

Magnitude: 8.92

Stars: 10 billion

Apparent size (V): 21′.9 × 11′.0

Leo I

  • Dwarf galaxy

Leo I is a dwarf spheroidal galaxy in the constellation Leo. At about 820,000 light-years distant, it is a member of the Local Group of galaxies and is thought to be one of the most distant satellites of the Milky Way galaxy. 

Apparent mass: ~0.02 billion Magnitude: 11.2

Constellation: LeoApparent size (V): 9′.8 × 7′.4

Apparent magnitude (V): 11.2

Distance: 820 ± 70 kly (250 ± 20 kpc)

Constellations:

Constellations are clusters of stars in recognizable patterns visible in the night sky. Major constellations include Big Bear(Ursa Major), Canis Major, Leo, etc. So far, 88 constellations have been discovered which are as given below:

  • Andromeda
  • Antila
  • Apus
  • Aquarius
  • Aquila
  • Aura
  • Aries
  • Auriga
  • Bootes
  • Caelum
  • Camelopardalis
  • Cancer
  • Canes Venatici
  • Canis Minor
  • Canis Major
  • Capricomus
  • Carina
  • Cassiopia
  • Centaurus
  • Cephus
  • Cetus
  • Chameleon
  • Circinos
  • Columba
  • Coma Berenices
  • Corona Australis
  • Corona Bonealis
  • Corvus
  • Crater
  • Crux
  • Cygnus
  • Delphinus
  • Dorada
  • Draco
  • Equleus
  • eridanus
  • Formax
  • Gemini
  • Grus
  • Hercules
  • Horologium
  • Hydra
  • Hydrus
  • indus
  • Laeerta
  • Leo
  • Leo Minor
  • Lepus
  • Libra
  • Lupus
  • Lynx
  • Lyra
  • Mensa
  • Microscopium
  • Monceros
  • Musca
  • Norma
  • Octans
  • Ophiuchus
  • Pavo
  • Pegasus
  • Perseus
  • Phoenix
  • Pictor
  • Pisces
  • Piscis
  • Puppis
  • Pyxis
  • Reticulum
  • Sagitta
  • Sagittarius
  • Scorpius
  • Sculptor
  • scutum
  • Serpens
  • Sextans
  • Taurus
  • Telescopium
  • Triangulum
  • triangulum astrale
  • Tucana
  • Ursa Major
  • Ursa Minor
  • Vela
  • Virgo
  • Volans
  • Valpecula
  • Orion

Comets:

The name comet has been derived from the Greek word Kometes meaning ”Hair Like”. A comet is a large snowball of frozen gases with very little solid matter. it possesses a small nucleus of ice and dust surrounded by bright cloud of gas and dust. there are about 100,000 comets in our solar system. The comets can be classified into short period comets and log period comets. Out of these, the former such as Hailey’s Comet have orbital period of less than 150 years where as the latter have orbital periods of ten thousand years. Some important comets are detailed as under:

(1). Hailey’s Comet:

This comet was discovered by Edmund Hailey in 1682. This comet appears after 76 years period. In 1705, Edmund Hailey said that the comet appearing in the years 1531, 1607, 1682 was the same Hailey’s comet. according to Haiey’s prediction, this comet reappeared in 1758, 1910, 1986.

(2). Comet Smith Tuttle:

This comet was first sighted in 1862 and reappeared in 1992. comet ‘Smith Tuttle is a k kiometer huge ball traveling with a speed of 60 km/s.

(3). Comet Shoemaker Levy-9:

This comet was discovered by scientists Sheomaker, Carolyn andLevy. It is about 10 km long and weighs about 500 billion tons.

A comet can have a nucleus up to 1000 miles in diameter and a tail up to 20 million miles long. On 16th July, 1994, comet Shoemaker was broken into 21 pieces when it crashed in to the surface of Jupiter producing scars on the planet.

Stars:

A star is gigantic ball of superheated has and keeps hot through nuclear reactions in its center. Sun is also a star in which heat and light is produced through fusion of hydrogen and fission of Helium. It is estimated that the temperature at the core of Sun is 36 million degree Fahrenheit. Thus Star is a luminous body in the sky. Large stars explode a supernovae and the surviving core forms Neutron Stars or Black Hole. Through their gravitational forces, the stars form galaxies by attracting millions of other smaller stars.

Brightest Stars of the Universe

Sr. No Name of Stars Constellations Mag Distance in Light years
1 Serius Canis Major -1.5 8
2 Canopus Carina -0.9 650
3 Alpha Centari Centaurus 0.1 4
4 Vega Lyra 0.1 23
5 Capella Auriga 0.2 42
6 Arcturiss Bootes 0.2 32
7 Rigel Orion 0.3 545
8 Procyon Canis Minor 0.5 10
9 Achemar Eridanus 0.6 70
10 Beta Centauri Centarius 0.9 130
11 Altair Aquita 0.9 18
12 Betelgewse Orion 0.9 600
13 Aldebaran Taurus 1.1 54
14 Spica Virgo 1.2 170
15 Pollux Gemini 1.2 90
16 Antares Scorpions 1.2 170
17 Fomalhunt Piscis 1.3 27
18 Deneb Cygnus 1.3 465
19 Regulus Leo 1.3 70
20 Beta Crucis Crux 1.5 465
21 Eta Carinae Carina 1.7 465
22 Alpha One Crux 1.6 150
23 Castor Gemini 1.6 44
24 Gamma Crucis Crux 1.6 44
25 Epsilon Canis Canis Major 1.6 325
26 Epsilon Ursae ursa Major 1.7 50
27 Bellatrix Orion 1.7 215
28 Lambde Scorpii Scorpion 1.7 325
29 Epsilon Carina Carina 1.7 325
30 Mira Cetus 2.1 250
Famous stars.

Satellites:

Satellite is a large body which revolves around a planet. The Solar System has 162 satellites. Out of these satellites, Jupiter has 63, Saturn has 56, Uranus has 27, Neptune has 13, Mars has 2 and Earth has one satellite(Moon). Major Satellites of Solar System are as under:

Planets and satellites - CBSE Class VI Social Science lesson - YouTube
Planets and Their satellites.
  • Earth: Moon
  • Mars: Phobos, Deimos.
  • Neptune: Triton, Nereid
  • Uranus: Miranda, Areil, Umbrial, Titania, Oberson.
  • Jupiter: Metis, adrastea, Amalthea, Thebe, Lo, Europa, Ganymede, Callisto, Leda, Elara, Himalia, Lysithea.
  • Saturn: Mimas, Tethys, rhea, Titan, Hyperion, Phoebe, Tetheys Co

Meteors:

A meteor is a small cosmic body which gives a streak of light when it burns up and entering the atmosphere of the Earth. This phenomenon also takes place when the Earth passes through a steam of meteors at the same time each year. An interplanetary rock may have a mass ranging from 10-7 gram to complete asteroid weighing several thousand tons. Due to the long streak of light, the meteor is called a shooting star. The largest meteorite weighing about 70 tons was found at Hoba in Namibia. The fragments of the Meteor fall on Earth creating craters in the surface of Earth.

A meteorite is a piece of cosmic debris weighing over 100 kg that falls on the earth. Thousands of Meteorites fall to the Earth each year. So far, the largest meteorite weighing 70 tons lies embedded near Grootfontein (South West Africa). Similarly another meteorite weighing 34 tons is in exhibition in New York.

New theory may explain the 'music of the meteors' | Science | AAAS
Night view of a Shooting Star

Difference among Meteoroid, Meteor and Meteorite:

Meteor: When a small piece of cometary or asteroidal material enters into atmosphere of Earth, it blazes due to friction with atmospheric air and burns down. It is observed in the form of Light streak. It is called Meteor.

Meteoroid: Before entering into Earths’s atmosphere, a cometary material is floating in space near the planet. Now it is called Meteoroid.

Meteorite: Most meteoroids that enter the atmosphere burn up completely as meteors. In some cases, however, the meteoroid does not completely burn up, and the object actually makes it to Earth’s surface. The chunk that has survived its fiery journey and fallen on the surface of Earth is called a meteorite. Or the Unburnt pieces of a Meteor which all on the surface of Earth are called Meteorites.

Constellations:

Constellations are clusters of stars in recognizable patterns visible in the night sky. Major constellations include Big Bear (Ursa Major), Canis Major, Leo, etc. So far, 88 constellations have been discovered.

Constellations and asterisms: what's the difference? - skyatnightmagazine
Night Sky with Constellations
  • Andromeda
  • Antila
  • Apus
  • Aquarius
  • Aquila
  • Aura
  • Aries
  • Auriga
  • Bootes
  • Caelum
  • Camelopardalis
  • Cancer
  • Canes Venatici
  • Canis Minor
  • Canis Major
  • Capricomus
  • Carina
  • Cassiopia
  • Centaurus
  • Cephus
  • Cetus
  • Chameleon
  • Circinos
  • Columba
  • Coma Berenices
  • Corona Australis
  • Corona Bonealis
  • Corvus
  • Crater
  • Crux
  • Cygnus
  • Delphinus
  • Dorada
  • Draco
  • Equleus
  • eridanus
  • Formax
  • Gemini
  • Grus
  • Hercules
  • Horologium
  • Hydra
  • Hydrus
  • indus
  • Laeerta
  • Leo
  • Leo Minor
  • Lepus
  • Libra
  • Lupus
  • Lynx
  • Lyra
  • Mensa
  • Microscopium
  • Monceros
  • Musca
  • Norma
  • Octans
  • Ophiuchus
  • Pavo
  • Pegasus
  • Perseus
  • Phoenix
  • Pictor
  • Pisces
  • Piscis
  • Puppis
  • Pyxis
  • Reticulum
  • Sagitta
  • Sagittarius
  • Scorpius
  • Sculptor
  • scutum
  • Serpens
  • Sextans
  • Taurus
  • Telescopium
  • Triangulum
  • triangulum astrale
  • Tucana
  • Ursa Major
  • Ursa Minor
  • Vela
  • Virgo
  • Volans
  • Valpecula
  • Orion

Auroras:

These are the northern and the southern lights. Out of these, the northen lights are also called Aurora Borealis and the Southern lights are called Aurora Australis. These lights are luminous occurrence in high altitude in various shapes such as arcs, bands and patches. According to modern research, auroras take place due to leakage of electrons from the outer Van Allen layer.

The 7 Best Places to See the Northern Lights and Southern Lights
Aurora Borealis
Aurora Australis puts on a show across Tasmania | The Examiner |  Launceston, TAS
Aurora Astralis

Quasar:

Quasar is a quasi-stellar object which emits tremendous amount of light and microwave radiation. According to an estimate, the quasars emit 100 times as much light as an entire galaxy comprising of millions of stars. The Source of light produced by quasar is the billions of stars which are stuck up in the black holes.

Pulsar:

Pulsar is a celestial body which emits radiations at regular interval. It is a rotating Neutron Star which is a star that has gone gravitational collapse and its atoms coalesce into neutrons. The radiation of Pulsar is generated by the electrons moving in the star’s magnetic field.

NASA continues to study pulsars, 50 years after their chance discovery
Pulsar.

Eclipses:

An eclipse takes place when an astronomical body during its revolution passes through the shadow of another body. The Solar eclipse, and lunar eclipse are its examples. The Solar eclipse takes place when the Moon comes between the Sun and the Earth. As a result, part or full part of the Sun looks black.In the Lunar eclipse, the Earth comes between the Sun and the Moon. Lunar eclipses occur when Earth’s shadow blocks the sun’s light, which otherwise reflects off the moon. There are three types — total, partial and penumbral — with the most dramatic being a total lunar eclipse, in which Earth’s shadow completely covers the moon.

Total Lunar Eclipse - Blood Moon

Moon:

Moon is a satellite of Earth which revolves around it at a distance 221,463 miles to 252,710 miles. It completes a revolution around the Earth in 27 days and 7 hours. Moon has a diameter of 2,160 miles. Moon is illuminated by the light taken from the Sun. Thus lunar eclipse takes place when The earth comes between Moon and the Sun. The moon revolves around its axis also in 27 days and 7 hours, thus it has only one side which is visible from Earth. It is about 1/4th the size of the Earth. Moon became the first planet to have been visited by man on July 21, 1969, when US astronauts, Neil Armstrong and Edwin Aldrin landed on its surface. Moon has no satellites of its own.

Space:

Space is the vast area which lies between the planets and stars in the Universe. Space is without air and magnetic field. Thus a man becomes weightless in space. The astronauts wear a space suit which helps them survive in space. They travel in specially designed space stations.

Space Stations:

Space station is a large space craft in which the astronauts remain in space for long period to conduct experiments. Soviet Union became the first country in 1971 to launch a space station named Salyut-I. Two years later, in 1973, USA followed by putting Skylab in the orbit of the Earth.

 

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