1. Solar system .
2. planets & asteroids & comets .
3. comet Elenin ( main topic ) .
The solar system :
- It was formed 4.6 billion years ago , and it consists from medium- sized star ( the sun ) which dominated by its huge gravity on all the objects in the solar system like planets , asteroids and comets .
- The solar system is divided into two regions : Mercury , Venus , Earth and Mars make up the inner solar system & Jupiter , Saturn , Uranus and Neptune make up the outer solar system ( gas giants ) .
- The four planets of the outer solar system make up 99% of the known mass orbiting the sun .
- Kuiper Belt :
is an area located in space beyond the orbit of Neptune at a distance of about 50 AU from the sun , and contains thousands of small icy objects, the Kuiper belt is important to study the solar system, where it was likely that the Kuiper belt objects are the remnants of very early stages of the solar system.
is a huge spherical cloud surrounding the solar system and extends for a distance of three years light, this distance is on the edge of the sun gravity ,there are alot of comets in this cloud which have a weak attraction with the sun , so any star can affect on their orbits and can send them outside the solar system .
Planets & Asteroids & Comets :
The IAU defined the planet as a celestial body orbiting a star or stellar remnant that is massive enough to be rounded by its own gravity.
So after this a new definitation , Pluto is no longer a planet because it doesn’t match the specifications and it becomes a dwarf planet ( asteroid ).
are small solid bodies have a round & irregular shapes , extending several hundreds of kilometers, but most of it is small scale, More than 100,000 asteroids lie in a belt between Mars and Jupiter , Ceres is the biggest one .
is a icy small solar system body, in most cases has a tail , it like a block of ice and dust .
- Some of comets pass by our solar system periodically and repeat its rotations like Comet Halley which was predicted to pass by solar system in 1986 by the astronomer Edmond Halley.
- Comet Hale – Bopp is one of the brightest comets watched in 1997 .
Comet Elenin :
It was discovered by Russian amateur astronomer Leonid Elenin in 10/12/2010 .
In 10 / 09 / 2011 it was the closet approach from the sun .
In 16 / 10 / 2011 it was the closet approach from the earth.
It was believed that when the comet becomes on the straight line between the earth and the sun , this comet will make a bad effects on the earth like earthquakes , thunder….etc and it can finish the life on the earth .
But it was wrong because in 26 / 09 / 2011 , the comet was on the straight line between earth and sun and nothing happened .
- This comet is far away , when it was in the closet approach from the earth , the distance was 35 million Km ( 90 twice the distance between the moon and the earth ) .
- The comet is very very tiny , its diameter doesn’t exceed 5 kilometers .
. So how this tiny far comet has effects on our planet !!!!
- Although the moon ‘s bigger than Elenin and closet to earth more than it , moon hasn’t effects on earth except Tides .
- Every few years we get almost that close to Venus (23.7 million miles), a rocky planet nearly the same size as our own, and don’t suffer any ill
- effects. unLike the comet, its pull on Earth is tiny, tiny, tiny.
Recommended Links :
Video about solar system :
Observing with Nasa :
Near- earth object program :
Location : AUC “Tahrir Spuare”
Instructor : Dr.Alaa Ibarhim.
Date : Fri. 21/10/2011.
By: Muhamed Hecham.
Magnology Space Club.