The wonderful universe and human According to the human knowledge the endless universe increases human curiosity obout it every day. I am also one of them who have the curiosity obout our universe.It is a wonderful feeling when someone feel the mystery of it. Galaxies The universe consist of billions of galaxies.Most of these galaxies are not identified by human.The galaxy which contains our earth has is called thw MILKY WAY.The stars which we can see in night are in our milky way. the solar system which includes our earth , sun and other planet is a tiny piece of the milky way. Harlow shapely is the scientist who has the honour of identify the size of the milky way.According to him oue galaxy has a diameter about 100,000 light years.If it is from miles it is about 4*1017.It is meantioned that the milky way’s age is about 20 billion years and it consist of about 1000 million stars. In 1960 it was discovered by the scientists the weight of our milky way is about 2*1011 times than our sun. Andromeda galaxy The closest galaxy to our milky way is the Andromeda galaxy.It can be seen as a small smoke cloud in September in north sky with human eyes.A Arabic scientist Al sufi(1903-1986) is the first scientist to meantion about the existence of Andromeda galaxy.But the germa scientist Simon Marios is the first scientist who published the scientific informations about Andromeda galaxy.In 1920 an American scientist Edwin Powell Hubble show the world that the Andromeda galaxy is an independent galaxy not a part of our galaxy. So it is time to start the journey…… The family of the sun The solar system is called as the family of the sun.This includes the sun,9 planets which orbits around the sun,moons, Sun Distance from the earth-1.0Au/150m km Diameter-1,391,400 km Mass-1.99*1030 kg Volume(earth=1)-1.3*105 Density(water=1)-1.412 Rotation time-25.4 days Number of planets-8 Number of moons-66 Thing on the surface-H2 and He Sun is the only star in our solar system. The light which is released by the sun arrives to the earth by 8 minutes.Earth is effected by its radiations.The sun which has a diameter of 1,391,400 km is about 10 times bigger than the Jupiter which is the biggest planet in our solar system. The surface temperature of the sun is about 15,000,0000C.Because of this heat any kind of a metal cannot be exist in the sun.So the sun is created with gases. If we compare Sun’s mass with the addition of the masses of other planets it is about 743 times than the addition of other planets. We can see some kind of spots on the surface of the sun.The specific thing about it is the situation of those spots vary with the time.By this it can be proved that the sun is also rotate around itself.It takes 25 days to rotate a complete round around itself. The contains of the sun. The Sun is, at present, about 70% hydrogen and 28% helium by mass everything else amounts to less than 2%. This percentages change slowly over time as the Sun converts hydrogen to helium in its core. In 1868 two scientists called Pierre Janssen and Norman Lockeyer have found that there is new material on the surface of the sun.This is named as He. The power of the sun The Sun's power (about 386 billion billion megaWatts) is produced by nuclear fusion reactions. Each second about 700,000,000 tons of hydrogen are converted to about 695,000,000 tons of helium and 5,000,000 tons (=3.86e33 ergs) of energy in the form of gamma rays. As it travels out toward the surface, the energy is continuously absorbed and re-emitted at lower and lower temperatures so that by the time it reaches the surface, it is primarily visible light. For the last 20% of the way to the surface the energy is carried more by convection than by radiation. Solar eclipse It just happens that the Moon and the Sun appear the same size in the sky as viewed from the Earth. And since the Moon orbits the Earth in approximately the same plane as the Earth's orbit around the Sun sometimes the Moon comes directly between the Earth and the Sun. This is called a solar eclipse; if the alignment is slighly imperfect then the Moon covers only part of the Sun's disk and the event is called a partial eclipse. When it lines up perfectly the entire solar disk is blocked and it is called a total eclipse of the Sun. Partial eclipses are visible over a wide area of the Earth but the region from which a total eclipse is visible, called the path of totality, is very narrow, just a few kilometers (though it is usually thousands of kilometers long). Eclipses of the Sun happen once or twice a year. If you stay home, you're likely to see a partial eclipse several times per decade. But since the path of totality is so small it is very unlikely that it will cross you home. So people often travel half way around the world just to see a total solar eclipse. To stand in the shadow of the Moon is an awesome experience. For a few precious minutes it gets dark in the middle of the day. The stars come out. The animals and birds think it's time to sleep. And you can see the solar corona. It is well worth a major journey. Our sun is the life of our solar system.It provides us the light,energy,power and so many things.Every thing of the human is depends on the sun.If there is an end of the sun it will be the end of us.so it justifies the why the ancient people treat sun as a god. Earth Earth, which is our home and the only planet with life according to the discoveries done up to today. So it is very important to study about our earth. We can study about Earth without the support spacecraft .But until the twentieth century we did not have maps of the entire planet. As the technology improved pictures of the Earth taken from spacecrafts are very important for human in various ways. for example, They are very helpful in weather prediction and especially in natural disasters. And they are extraordinarily beautiful The Earth can be divided into several layers which have distinct chemical and seismic 0- 40 Crust 40- 400 Upper mantle 400- 650 Transition region 650-2700 Lower mantle 2700-2890 D'' layer 2890-5150 Outer core 5150-6378 Inner core Most of the mass of the Earth is in the mantle, most of the rest in the core; the part we live is a small fraction of the whole (values in x1024 kilograms): atmosphere = 0.0000051 oceans = 0.0014 crust = 0.026 mantle = 4.043 outer core = 1.835 inner core = 0.09675 The core contains mostly of iron. But there is a possibility that some lighter elements can also contain in the core. Temperature at the center of the core is about 7500 K, which is hot than the surface of the Sun. The lower mantle contains mostly silicon, magnesium and oxygen with some iron, calcium and aluminum. The upper mantle is mostly olivene and pyroxene, calcium and aluminum. We can see most of the times samples from the upper mantle arrive at the surface as lava from volcanoes but the majority of the Earth is inaccessible. The crust is primarily quartz (silicon dioxide) and other silicates. Earth's chemical composition 34.6% Iron 29.5% Oxygen 15.2% Silicon 12.7% Magnesium 2.4% Nickel 1.9% Sulfur 0.05% Titanium When we consider about Earth’s atmosphere the Earth's atmosphere is 77% nitrogen, 21% oxygen and few other gases. Earth is the only planet which has liquid water on its surface. This liquid water and oxygen creates a suitable environment for human to live and born. I hope this will give you a good understanding about our Earth. In future we will be discussing on more complex information and characteristics of the Earth.
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