DWARF PLANET

  Any celestial body orbiting around the sun, weighing for the self-gravity and nearly be round in shape is called ‘Dwarf Planet’.

E.g.: Ceres, Pluto, Haumea, Make make and Eris

SATELLITES

The satellites move around a planet from West to East.

They do not have own light, but reflect the light of the Sun.

They have no atmosphere and water.

The moon is the earth’s natural satellite.

The moon moves around the earth in about 27 days. It takes exactly the same time to complete one spin. As a result, only one side of the moon is visible to us on the earth.

ASTEROID

Asteroids are small rocky celestial bodies that revolve around the Sun, like other Planets. These are found in between the planets Mars and Jupiter. This belt is known as ‘Asteroid belt’.

When an asteroid collides with the earth, then a huge crater is formed on the surface of the earth. For example: lonar lake in Maharashtra.

COMETS

unlike the other small bodies in the solar system, comets have been known since antiquity. There are Chinese records of Comet Halley going back to at least 240 BC. The famous Bayeux Tapestry, which commemorates the Norman Conquest of England in 1066, depicts an apparition of Comet Halley.

By far the most famous comet is Comet Halley but SL 9 was a “big hit” for a week in the summer of 1994.

Meteor shower sometimes occur when the Earth passes thru the orbit of a comet. Some occur with great regularity: the Perseid meteor shower occurs every year between August 9 and 13 when the Earth passes thru the orbit of Comet Swift-Tuttle. Comet Halley is the source of the Orionid shower in October.

Comet Comets are snowballs made up of frozen gas, rock, and dust that orbit the Sun. As they get closer to the Sun, they heat up and leave a trail of glowing dust and gases.

Comet is also the heavenly body located on the outermost part of the solar system. They are made up of small ice particles and meteoric fragments. As the comet approaches the sun, it develops a long, glowing tail.

Comets are sometimes called dirty snowballs or “icy mudballs”. They are a mixture of ices (both water and frozen gases) and dust that for some reason didn’t get incorporated into planets when the solar system was formed. This makes them very interesting as samples of the early history of the solar system.

When they are near the Sun and active, comets have several distinct parts:

• nucleus: relatively solid and stable, mostly ice and gas with a small amount of dust and other solids.
• coma: dense cloud of water, carbon dioxide and other neutral gases sublimed from the nucleus.
• hydrogen cloud: huge (millions of km in diameter) but very sparse envelope of neutral hydrogen.
• dust tail: up to 10 million km long composed of smoke-sized dust particles driven off the nucleus by escaping gases; this is the most prominent part of a comet to the unaided eye.
• ion tail: as much as several hundred million km long composed of plasma and laced with rays and streamers caused by interactions with the solar wind.

METEOROIDS

Meteoroids are lumps of rock or iron that orbit the sun, just as planets, asteroids, and comets do.

Meteoroids, especially the tiny particles called micrometeoroids, are extremely common throughout the solar system.

They orbit the sun among the rocky inner planets, as well as the gas giants that make up the outer planets. 

A meteoroid, comet, or asteroid enters Earth’s atmosphere at a speed typically in excess of 20 km/s (72,000 km/h; 45,000 mph), aerodynamic heating of that object produces a streak of light, both from the glowing object and the trail of glowing particles that it leaves in its wake. This phenomenon is called a meteor or “shooting star”. A series of many meteors appearing seconds or minutes apart and appearing to originate from the same fixed point in the sky is called a meteor shower. A meteorite is the remains of a meteoroid that has survived the ablation of its surface material during its passage through the atmosphere as a meteor and has impacted the ground.

An estimated 25 million meteoroids, micrometeoroids and other space debris enter Earth’s atmosphere each day, which results in an estimated 15,000 tonnes of that material entering the atmosphere each year