Grade 77 grade science
How the earth is formed and why does life is only on earth and why does the sun burns for this much years
How the earth is formed and why does life is only on earth and why does the sun burns for this much years
1 Answer
jyoti bhatia
When it comes to how the Earth was formed, forces that can only be described as fiery, chaotic, and indeed godlike, were involved. However, in the past few centuries, research and refinements made in what is today known as Earth Sciences have allowed scientists to assemble a more empirical and scientific understanding of how our world was formed.
Basically, scientists have ascertained that several billion years ago our Solar System was nothing but a cloud of cold dust particles swirling through empty space. This cloud of gas and dust was disturbed, perhaps by the explosion of a nearby star (a supernova), and the cloud of gas and dust started to collapse as gravity pulled everything together, forming a solar nebula—a huge spinning disk. As it spun, the disk separated into rings and the furious motion made the particles white-hot.
The center of the disk accreted to become the Sun, and the particles in the outer rings turned into large fiery balls of gas and molten-liquid that cooled and condensed to take on solid form. About 4.5 billion years ago, they began to turn into the planets that we know today as Earth, Mars, Venus, Mercury and the outer planets.
We really don’t know if life only exists on Earth! We do know that life as we understand it requires very special conditions to exist. In fact, many scientists believe that these conditions exist elsewhere and offer the possibility for life beyond just our Earth. These may be very simple organisms such as bacteria or even more complex life such as plants and animals. All living things need some sort of food, water, the right atmosphere and temperature. Humans for example, need to breathe in oxygen and can survive in temperatures that aren’t extreme hot or cold. Even the strength of gravity determines the form of our bodies such as our bones and muscle strength. Other planets don’t have exactly the same conditions as Earth so life would be somewhat different there. For example, these places may have a different atmosphere so there wouldn’t be the right amount of oxygen for us to breathe. All living things on earth have adapted to our atmosphere, which means all living things need our mix of atmospheric gases. Life elsewhere would be specifically adapted to their own conditions.
Water is a really important ingredient to sustain the kind of life we know on Earth. Both plants and animals require water for survival. Planet Earth is very special because it contains so much water in liquid form. We have yet to find a planet with the same amount of liquid water as on earth but there are many new “exoplanets” being discovered orbiting other stars that offer this possibility. One of things that the Mars Rover, Curiosity, is looking for is the presence of water now or evidence that it existed in the past on Mars. It appears that Mars did have lots of liquid water at one time. Conditions might have been right on Mars to support life.There is even the possibility that life formed on Mars before it formed on Earth and that Mars “seeded” life on Earth. For living things the correct temperature is really important. Most life on earth lives in warm to moderate temperatures. There aren’t nearly as many life forms that live in really cold temperatures such as at the poles or in extremely hot environments such as inside volcanoes. One factor that affects the temperature of a planet’s atmosphere is its distance from the star it orbits around – it’s “sun.” The planets closest to the sun are very hot, while planets that are farther out are much colder. People couldn’t survive on these planets. We are detecting “exoplanets” around other stars at the right distance to have the right temperature for life to exist. So, there still might be life on other planets, or even the moons of other planets, but it would probably be very different than life on Earth! These other possible forms of life would be very far away.
The sun has used up about half of its hydrogen fuel in the last 4.6 billion years, since its birth. It still has enough hydrogen to last about another 5 billion years. The temperature of the sun’s surface is about 10,340 degrees Fahrenheit (5,726 degrees Celsius).
The sun burns using a nuclear fusion process, combining hydrogen into helium. When the sun runs out of hydrogen, it will fuse helium and other heavier elements until it runs out of fuel.
Sun is made up of Hydrogen just like other stars. Hydrogen atom fuses in the process of Nuclear Fusion and gives out Helium and lot of energy. This energy we see as light and heat.
There is lots and lots of Hydrogen atoms and not only Hydrogen atom gives energy. Further Helium fuses to form other heavy elements which also gives out energy. This process is repeated till we get to Iron. Iron fusion doesn’t give out energy , it is an endothermic process.
Sun will continue burning till the maximum amount of hydrogen is burnt and converted to Iron. Once the iron goes high, the core becomes dense and create huge gravity and pulls the star inside and thus death of the star.
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