The Solar System

Solar System means system of the sun. All bodies under the gravitational influence of our local star, the Sun, together with the Sun, forms the solar system. The largest bodies, including Earth revolving around the sun are called planets. Often smaller cool bodies, called satellites and moons, orbit a planet. Bodies smaller than planets that orbit the sun are classifieds as Asteroids if they are rocky or metallic from the region between Mars & Jupiter, Comets if they are mostly ice & dust, and Meteoroids if they are very small.

Our Solar System

How Big is Our Solar system ?

To think about the large distances, we use a cosmic ruler based on the astronomical unit(AU). 1 AU is the distance from Earth to the Sun, which is about 150 million kilometres. the area of the Sun’s influence stretches far beyond the the planets, forming a giant bubble called the heliosphere. The enormous bubble of the heliosphere is created by the solar wind, a stream of charged gas blowing outward from the Sun. As the Sun orbits the center of the milky way, the bubble of heliosphere also moves ahead of itself in interstellar space through the interstellar gases. The area where the solar wind is abruptly slowed by pressure from gas between the stars is called the termination shock. That was observed when Voyager 1 began sending unusual data to Earth in late 2003. In December 2004, thats how scientists confirmed that Voyager 1 had crossed the termination shock at about 94 AU, approximately 13 billion kms from the sun,venturing into the vast, turbulent expanse where the Sun’s influence diminishes. Voyager 2, 16 billion kilometres from Voyager 1, crossed the termination shock in August 2007. Voyager 1 may reach in interstellar space sometime between 2014 & 2017; when voyagers exit the enormous Oort Cloud, a vast spherical shell of icy bodies surrounding the solar system.

Galaxies

Solar System: As we know it

A Solar system refers to a star and all the objects that travel in orbit around it. Our Solar system consists of the sun – our Star – Eight planets and their natural satellites (such as our moon); dwarf planets; asteroids and comets. Our solar system is locally in an outward spiral of the Milky Way galaxy.

Like early explorers mapping the continents of our globe, astronomers are busy charting the spiral structure of our galaxy, the Milky Way. Using infrared images from NASA’s Spitzer Space Telescope, scientists have discovered that the Milky Way’s elegant spiral structure is dominated by just two arms wrapping off the ends of a central bar of stars. Previously, our galaxy was thought to possess four major arms. This annotated artist’s concept illustrates the new view of the Milky Way, along with other findings presented at the 212th American Astronomical Society meeting in St. Louis, Mo. The galaxy’s two major arms (Scutum-Centaurus and Perseus) can be seen attached to the ends of a thick central bar, while the two now-demoted minor arms (Norma and Sagittarius) are less distinct and located between the major arms. The major arms consist of the highest densities of both young and old stars; the minor arms are primarily filled with gas and pockets of star-forming activity. The artist’s concept also includes a new spiral arm, called the “Far-3 kilo-parsec arm,” discovered via a radio-telescope survey of gas in the Milky Way. This arm is shorter than the two major arms and lies along the bar of the galaxy. Our sun lies near a small, partial arm called the Orion Arm, or Orion Spur, located between the Sagittarius and Perseus arms.

Our Solar System Consists of-

  • Planets:8 – The planet count in our solar system has gone as high as 15 before new discoveries prompted a fine tuning of the definition of a planet.
  • Dwarf planets:6 – This new class of worlds helps us categorize objects that orbit the Sun but aren’t quite the same as the rocky planets and gas giants of our solar system. There could be hundreds more of these small worlds far out there waiting to be discovered.
  • Moons:173 – This Counts includes only the moons orbiting the eight planets in our solar system. it is likely there are more moons orbiting the giant planets of our solar system and there are moons orbiting around dwarf planets and asteroids.
  • Asteroids:645,118 – New asteroids are discovered on an almost daily basis. it is estimated that the mineral wealth of the asteroid in the main belt between Mars and Jupiter is about $100,000,000 for every person on Earth.
  • Comets:3,279 – orbiting spacecraft such as SOHO have raised this tally in recent years by catching the comets as they plunge towards the Sun – and sometimes vaporize. Scientists estimated there could be as many as 1,000,000,000 comets held in the gravitational grip of the Sun.