Lunes, Oktubre 10, 2011

Planets in the Solar System


             The Solar System consists of the Sun and the astronomical objects gravitationally bound in orbit around it, all of which formed from the collapse of a giant molecular cloud approximately 4.6 billion years ago. Of the many objects that orbit the Sun, most of the mass is contained within eight relatively solitary planets whose orbits are almost circular and lie within a nearly flat disc called the ecliptic p . The four smaller inner planets, Mercury,Venus, Earth and Mars, also called the terrestrial planet, are primarily composed of rock and metal. The four outer planets, the gas giants are substantially more massive than the terrestrials. The two largest, Jupiter and Saturn, are composed mainly of hydrogen and helium; the two outermost planets, Uranus and Neptune, are composed largely of ices, such as water, ammonia and methane, and are often referred to separately as "ice giants".(www. Wikipedia.com)
            The Solar System is also home to a number of regions populated by smaller objects. The asteroids belt, which lies between Mars and Jupiter, is similar to the terrestrial planets as it is composed mainly of rock and metal. Beyond Neptune's orbit lie the Kuiper belt and scattered disc; linked populations of trans-Neptunian is object composed mostly of ices such as water, ammonia and methane. Within these populations, five individual objects, Ceres, Pluto, Haumea, Makemake and Eris, are recognized to be large enough to have been rounded by their own gravity, and are thus termed draft planets. In addition to thousands of small bodies in those two regions, various other small body populations, such as comets, centuars and interplanetary gas, freely travel between regions. Six of the planets and three of the dwarf planets are orbited by natural satellites, usually termed "moons" after Earth's Moon. Each of the outer planets is encircled by planetary rings of dust and other particles.(www. Wikipedia.com)


       By the current count of astronomers, our solar system includes 8 planets and 5 draft planets. The planets were formed during  the process of solar system formation, when clumps begun to form in the disk of gas and dusk rotating about our young Sun. Eventually only the planets and other small bodies in the solar system remained. The four rocky planet's at the center of solar system Mercury, Venus, Earth, Mars, are known as the inner planets. Jupiter, Saturn, Uranus and Neptune are all composed primarily of gas and are known as the outer  planets.


As you travel outward from the Sun, Mercury is the closest planet. It's orbits the Sun at the average distance of 58 million km. Mercury  is airless and so without significant atmosphere to hold in the heat, it has dramatic temperature differences. Mercury is also the smallest planet in the Solar System, measuring  just 4879 km across the equator. Mercury has only visited two times by spacecraft. The first was Mariner 10, back in the mid 1970s.  It wasn't until 2008 that another spacecraft  from the Earth made a close flyby of Mercury, taking new image of it's surface.
  
        Venus is the second planet in the Solar System, and it's an almost virtual twin of the Earth in terms of size and mass. Venus orbits at an average  distance of 108 km, and completes and orbit around the Sun every 224 days. Apart from the the size, though,Venus is very different from the Earth. It has an extremely thick atmosphere made almost entirely of carbon dioxide that cloaks the planet and helps heat it up to 460 degree Celsius.Several spacecraft have visited Venus, and a few landers  have actually made it down to the surface to sent back images of the hellish landscape.

                     The Earth is our home, the third planet from the Sun. It's orbit the Sun at an average distance of 150 km. Earth is the only planet in the Solar System known to support life. This is because our atmosphere keep the planet warm from the vacuum spaces, but it's not so thick that we have a runaway green house effect. No planet in the Solar System has been studied as well as Earth, both the ground and the space. Thousands of spacecraft have been launched to study the planet, measuring it's atmosphere. land masses, vegetation, water, and human impact Earth has only a single moon.

                 Mars the fourth closest planet to the sun, the second smallest planet in the Solar System.The planets itself was named Mars after the Roman god of war. It has also be been referred to as the red planet because of its reddish appearance.


                    Mighty Jupiter is the biggest in our Solar system and the fifth planet from the Sun. It is two and half times larger and then all the other planets in solar system combined. Jupiter is primary composed of hydrogen with a minute portion of helium.

Saturn is the 6th planet from the Sun, and the 2nd largest in the solar system.It orbit the Sun at average distance of 1.4 billion km. The most amazing feature of Saturn is it's ring. These are made of particles of ice ranging in size from a grains of sand to the size of a car. Saturn has been visited by spacecraft 4 times: Pioneer 11, Voyager 1 and 2 were just flybys Cassini has actually gone into orbit around Saturn and has captured thousands of images of the planet and it's moon. And speaking moons,Saturn has a total of 60 moons discovered so far. 
               Next comes Uranus, the 7th planet from the Sun. It orbits the Sun at an average distance of 2.9 billion km.Uranus was the first planet to be discovered with a telescope, it was first recognize as a planet in 1781 by William Herschel.


                   Neptune is the 8th and final planet in solar system, orbiting at an average distance of 4.5 kilometer from the Sun. It's the 4th largest planet, measuring about 49,000 km across.It might not be as big as Jupiter, but it's still 3.8 times larger than Earth. Neptune has only visited by one spacecraft, Voyager 2, which made a fly by in August 1989.Neptune has 13 known moons.


                And those are the planet in the Solar System. Unfortunately, Pluto isn't a planet anymore.




                    

Miyerkules, Agosto 3, 2011

"Hydorsphere a Beautiful Gift to Human World"


            In physical geography, the term "Hydrospehere" ( Greek hydro means "water" ) describes the collective mass of water found on, under, and over a planet's surface. The Earth's hydrosphere consists chiefly the oceans, but technically includes clouds, inlands seas, lakes, rivers,, and undergroundwaters. The earth's appears to be a blue  planet when seen from outer space. this is because more than two-thirds of the Earth's surface is water. We call this the hydrosphere. (www.newworldencyclopedia.org)





            The hydrosphere is important for many reason. It is essential to life. Neither plants nor animals can live without it. It provides the water that is needed by all living things. Not only do we drink water but we also use fresh water to irrigate the land. This enable us to grow food without having to rely on rain and we can grow more food this way. Oceans, lakes and rivers are themselves important sources of food. Fish is the major source of protein for many people around the world, and much of our salt comes from the sea, and this help flavor our food and also important natural preservatives.

           Even though we often perceived water to be very ordinary, we are dependent of water for survival. We use water for different activities like washing our clothes, cleaning, bathing and cooking. We are about two-thirds of water ourselves and require water to live. Life as we know it could not have been evolved without water and dies without it.

          The hydrosphere covers 3 quarters of the Earth's surface. A major part of the hydrosphere is the marine ecosystem in the ocean, while only a small part is fresh water. The fresh water in rivers, lakes and glaciers is perpetually being renewed by process of evaporation and rainfall;some of this fresh water is stored in underground aquires. Human activities, like deforestation, create serious changes in the hydrosphere . Once the land is denuded of vegetation,the rain erodes the soil,which is then washed into the sea.
         Chemicals from industry and sewage find their way into rivers and into the sea. Water pollution thus theaterns the health of communities,as all our lives depend on the availability of clean water.This once plentiful resource is now becoming rare and expensive due to pollution. Water also affects the weather, thus water can directly or indirectly add to the extremity of weather conditions such as drought brought by El Nino and the long rainy season La Nina. 
        
         We should protect our hydrosphere in order for us to have a good source of water to drink and good source of food from our oceans and rivers. Neglecting the importance of hydrosphere can lead to water shortage and we humans will suffer and face the consequences of not taking care of our water resources.