Celestial Objects

The Celestial objects which are objects in our sky, are of different types. Planets in Solar system, Moon, different types of stars and clusters, Asteroids, Comets all are contained in this list. Some of which and its details are mentioned here.

When we look at a celestial object we are looking at how it appeared that long ago in the past.

Milky way galaxy is a big place, even at this blazing speed, it takes the sun approximately 225-250 million years to complete one journey around the galaxy’s center. That amount of time – “the time takes us to orbit the center of galaxy” – is called a Cosmic year.

  •  Asteroids.

The Asteroid belt is a torus-shaped region in the solar system, located roughly between the orbits of the planets Jupitor and Mars, that is occupied by a great many solid, irregularly shaped bodies, of many sizes but much smaller than planets, called asteroids or minor planets.

These are rocky worlds revolving around the sun which are too small to be called as planets . Made up of Metals and rocks and consists of organic compounds . Which have shorter and elliptical orbits. Can found millions of asteroids that measures hundreds of kilometers across. Some as small as dust particles . Mass less than that of Moon.

Most of the asteroids are small but some have diameter as large as 100 Km. Which are revolving around the sun between the orbits of Mars and Jupiter.

  • Comets.

Comets also orbit the sun and are relatively small bodies of solar systems. When Comets approach the sun , some of their ice particles melt the other materials vapourises due to the heat of the Sun . This results in a glowing halo that extends outwards as though sailing through the space. The ice and compounds like ammonia and methane develop a fuzzy cloud-like shell known as Coma. This forms a notable difference between comets and asteroids . 

  • Meteors.

A meteor is a streak of light in the sky. A meteor, sometimes called a shooting star or falling star, is actually a space rock that is crashing through Earth’s atmosphere. A meteor is a streak of light in the sky caused by a meteoroid crashing through Earth’s atmosphere.

  • Halley’s Comet.

Halley’s Comet is arguably the most famous comet. It is a periodic comet and return to Earth’s vicinity about 75 years, making it possible for a human to see it twice in his or her lifetime. The last time it was here in 1986 , and it is projected to return in 2061.

Halley’s orbital period has varied between 74-79 years since 240 BC. Its orbit around the sun is highly elliptical with an orbital eccentricity of 0.967( with 0 being a circle and 1 being a parabolic trajectory) The perihelion, the point in the comet’s orbit when it is nearest the sun, is just 0.6 AU.


Black hole is a region of space from which nothing, not even light, can escape. It is the result of the deformation of Space time caused by a very compact mass.

The simplest black hole has mass but neither electric charge nor angular momentum. The mass of the blackhole is finite. But has very high density, the reason why a blackhole has infinite density is that its mass is concentrated into a space of zero-volume.

Chandrasekhar determined what is known as the Chandrasekhar limit-that is a star having a mass more than 1.44 times that of the sun does not form a White dwarf but instead continues to collapse , blows off its gaseous envolope in a supernova explosion, and becomes a neutron star.

Recently Scientists observed the merge of giant “black holes” billions of light years away from the earth. The blackhole is supposed to be located in Abel 2261, an enormous galaxy cluster that is about 2.7 billion light years away from our planet. At 2.7 billion light years away, the Abel Galaxy is at an overwhelmingly large distance away from us.

  • Planets

The order of the planets in the solar system, starting nearest the sun and working outwards is the following : Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and then the possible planet Nine.

Planets have an apparent motion but does not twinkle. Planets do not twinkle because 

1) Planets are not a source of light instead they reflect low intensity light reaching them.

2)They are also closer to the earth than the distant stars. Hence the shift is not enough for the planets to twinkle.

Because of the lack of an atmosphere in moon ,  sunlight omited is scattered. So whether its daytime or night time on the moon, the sky appears black.  

  • Earth

When the earth was created more than 4000 million years ago, there was 54% oxygen and no carbon dioxide. When living organisms originated, they modified the early atmosphere of the earth.

The early atmosphere largely contained water vapor, nitrogen, carbon dioxide, methane, ammonia and very little of free oxygen. The process through which the gases were outpoured from the interior is called degassing. Continuous volcanic eruptions contributed water vapor and gases.

The energy from earth, Geothermal energy is the heat received from the earth’s core, this heat continuously flows outwards. It transfers to the surrounding layers of the rock, the mantle. When temperature and pressure becomes very high some mantle rocks melt becoming magma.

From electromagnetic radiation to revolution of the earth everything is responsible for bringing dynamic changes on the surface of the earth and that changes made the earth as of the form that we live now.

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