Other members of solar system

Science 8

1. Other members of solar system

2. COMETS heavenly bodies which are cloudy in appearance revolving around the Sun. They contain a nucleus inside a cloud-like coma. As they come near the Sun, they develop a tail due to the melting of icy constituents and dusts blown away by the solar wind. The tails points away from the Sun. As it moves away from the Sun, the tail disappears. Comets are seen periodically.

3. example ENCKE’S COMET Comet 2P/ Encke was first discovered by Pierre F. A. Mechain on Jan. 17, 1786. Other astronomers located this comet in subsequent passages, but these sightings were not defined as the same comet until Johann Franz Encke calculated its orbit . It takes 3.30 years for Enke to orbit the sun once.

4. example HALLEY’S COMET Halley was last seen in Earth's skies in 1986 and was met in space by an international fleet of spacecraft. It will return in 2061 on its regular 76-year journey around the Sun . Comets are usually named for their discoverer(s) or for the name of the observatory/telescope used in the discovery. Since Halley correctly predicted the return of this comet ​— the first such prediction — it is named for him to honor him. The letter "P" indicates that Halley is a "periodic" comet. Periodic comets have an orbital period of less than 200 years.

5. example COMET C/1995 O1 (HALE-BOPP) was discovered in July 23, 1995, independently, by both Alan Hale and Thomas Bopp. Hale-Bopp was discovered at the amazing distance of 7.15 AU. One AU is equal to about 150 million km (93 million miles ).

6. COMETS They have nebulous appearance and elongated orbits. The nucleus is the only part that can be seen with a large telescope even when still far away from the Sun. This cometary nucleus is an irregularly shaped mass composed of largely frozen water mixed with substantial amounts of carbon the form of fine dust.

7. Origin of comets Comets are as old as the solar system and are the remnant of the building blocks that produced the giant planets. Hundreds of millions of comet nuclei exist in a spherical region called Oort Cloud that surrounds the solar system.

8. Two types of comets Short-period comets are those that are periodically observed in less than two hundred (200) years. Comet Halley with an average period of 76 years is the only one that returns in a single lifetime. It is among those comets that can be easily seen with the naked eye. Long-period comets are those with periods of more than or 2 000 years. C omets bodies were investigated for the first time with spacecraft during the mid-1980s. 1985 – US Probe known as ICE (International Cometary Explorer) passed through the dust tail of comet Giacobini-Zinner . 1986 – Spacecraft launched by Japan and USSR along with the Giotto Probe of ESA (European Space Agency) flew by Comet Halley, transmitting many useful data about its composition and sending pictures of its nucleus.

9. METEOROIDS any interplanetary object of relatively small size that enters the Earth’s atmosphere. vast majority of meteroids burn up in the upper atmosphere, but occasionally one of relatively large mass survives.

10. METEOR the resultant luminous phenomena, due to the collision with the atoms and molecules of the atmosphere at high velocity, the object begins to burn up and heats the air around . Also known as a shooting star or falling star and can be seen as a streak of light in the sky.

11. METEORITE object survives its plunge through the atmosphere and strikes the ground. Termed used to similar objects reaching the surface of other planets or satellite.

12. Studies suggest that the majority of meteroids re fragments of asteroids produced by collisions between objects in the asteroid belt lying between the orbits of Mars and Jupiter. Evidences says that some meteroids are of cometary origin. Some of the meteroids entering the Earth’s atmosphere came from the dust embedded in a comet. Meteor showers become visible when the Earth encounters swarms of meteroids moving together. Eta Aquarid is meteor shower which can be seen every year in early May, has been identified with Comet Halley. The meteoroids in the swarm producing this shower are thought to be debris ejected from the comet along its orbit.

13. ASTEROIDS rocky bodies that move in elliptical orbits around the Sun like planets do. Most asteroids rotate on their axis. Most of them are found between Mars and Jupiter, known as Asteroid belt which separates the inner planets from the outer planets. The bigger ones are Ceres, Pallas, and Vesta . In 1992, an asteroid was found between Neptune, one of the first of the Kuiper belt ( Edgeworth -Kuiper belt). In 1996, asteroids near the earth were discovered. One of the largest near-Earth asteroid is Eros.

14. ASTEROIDS also known as planetoids or minor planets being smaller, rocky astronomical objects than any of the eight planets of the Solar System. By the 1990s, more than 7000 asteroids had been observed and 5 000 of them had been assigned numbers, done as soon as accurate orbital elements have been determined. There are about 30 few large asteroids having a diameter of more than 300 kilometers (km).

15. Ceres – the largest known asteroid discovered in 1801, has a diameter of roughly 935 km. Pallas – the second sie , measures 535 km across.

16. Approximately 250 asteroids have a diameter of at least 100 km. it is estimated that millions of asteroids of boulder size exist in the solar system. In 1993-1994 images were produced by spacecraft Galileo passing through the asteroid belt on its way to Jupiter showing an asteroid that has its own tiny moon. As potato-shaped asteroid named Ida with a length of about 56 km is orbited at a distance of roughly 100 km by a rock that is about 1.5 km in diameter and is the smallest known natural satellite in the solar system.