Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Big Bang theory:
The most important current theory for the origin of the universe is the Big Bang theory.According to this theory, the universe started with'a huge explosion. It was not an explosion like the ones with which we are familiar, which start from a definite centre and spread out. It was an explosion which occurred everywhere in space at the same time. It filled all space from the beginning, with every particle of matter rushing apart from every other particle. This was not a burst of matter into space but rather an explosion of space itself. Every particle of matter rushed away from every other particle. It is so far impossible to 'picture' the fi~st moment of 'creation' of the universe. One-hundredth of a second after the creation of the universe is the earliest time about which scientists can speak with any confidence. At this instant, the temperature of the universe was about a hundred billion degrees centigrade. This-is much hotter than in the centre of even the hottest star. At such temperatures none of the components of ordinary matter, atoms, molecules, or even nuclei of atoms, could have held together. Instead, the matter rushing apart in the explosion consisted of various types of elementary particles. The particles most abundant in the early universe were the electrons, positrons and neutrinos. There were also some protons and neutrons. The rest of the universe was filled with energy. It was a kind of a cosmic soup. As the explosion continued, matter and energy rushed apart, the universe expanded and the temperatures dropped, reaching 30 billion (3x1010) degrees centigrade after about one-tenth of a second; 10 billion degrees after about one second; and 3 billion degrees after about fourteen seconds. At the end of the first three minutes, the universe became cool enough (about 1 billion 0C) for the protons and neutrons to begin to form into simple nuclei. The first to be formed was the nucleus of heavy hydrogen which was made up of one proton and one neutron. There were also helium nuclei made of two protons and two neutrons. It was still too hot for atoms to hold together, they were ripped apart as soon as they were created. This matter continued to rush apart, becoming steadily cooler and less dense.
Many thousands of years later, it became cool enough for electrons to join with nuclei to form atoms of hydrogen and helium. Soon, the resulting gas began to form clumps under the influence of gravitation. These clumps ultimately condensed to form the galaxies and stars of the present-day universe, almost 5 billion years after the Big Bang. There is another theory about the origin of the universe known as the steady state theory. This theory holds that the universe has always been just about the same as it is now. As it expands, new matter is created continuously to fill up the gaps between the galaxies. Thus, the problem of the origin and early moments of the universe is banished: there was no early universe. However, the Big Bang theory is the most favoured by the astronomers and astrophysicists. Why is it so? This is due to the evidence based on observations which lend support to the 'Big Bang' universe.
What is a covalent crystal? A covalent crystal is one in which the lattice structure is held together by powerful covalent bonds. These crystals tend not to be soluble in water
Explain the Foetal Monitoring During late pregnancy and during labour, a physician may want to monitor the foetal heart rate and other functions. Foetal heart rate monitoring i
solar system At night you can see very many stars in the sky. But during the day, only one star is .visible, and that is the Sun. This is not because there is anything extrao
what is the decimals for 23
What happens if the elasticity of Price expectations is less than one?
what is the regulation of steady conditions inside an organism
Explain Factors Affecting viscosity of Blood Viscosity of blood affects the systemic blood pressure in the same way as changes in the peripheral resistance. In anaemia, viscos
Explain in brief about the Crop Rotation 1. Deep rooted legumes may be grown periodically over all fields. 2. There is more continuous vegetative cover and probably less e
Question 1 Database design plays important role in success of CDM. Justify Question 2 What is Clinical data coding? Why coding is required in CDM? Question 3 List
What is the only usual mineral to be strongly magnetic other than magnetite: Pyrrhotite
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd