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.
PROCEDURE : Your Counsellor will be performing the following experiments. You are advised to observe the disposal methods carefully. Experiment 1: Test for studying miscibility
how long do people live
1. identify ten diagnostic medical term that use diagnostic, note the suffixes and provide the definitions.2. then identify ten related procedural medical terms that use procedural
Personal Protective Devices : We shall now discuss the details of protective devices required for safety in a laboratory. The aim of protective devices is to minimise the risk of
Starch is a non-reducing substance , as except one carbonyl group, all other carbonyl groups are involved in glycosidic bond formation. It may be hydrolyzed by boiling with hyd
economic importance
Explain the Dichromates or Mild Colour Blindness A dichromate individual possesses only two cone pigments. Lack of the red pigment, called protanopia, makes distinguishing of t
How to make a simple apparatus for distilling water You can make a easy water-distilling apparatus from a flask, and a length of glass or rubber tubing. Fit the flask with a si
Deductive logic: Deductive logic may be considered as the opposite of induction. Here the reasoning is more direct. If we know a statement about a whole class of objects, ph
Linh has been brought by ambulance to the Emergency Department of the local metropolitan hospital where you are working, following a drug overdose of thirty Paracetamol tablets whi
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