Welcome to the Official English Website of the Savior of Mankind Imam Ahmed al-Hasan PBUH
- 22 February 2014
- Super User
May the peace, mercy and blessings of Allah be upon you.
I ask Allah for you to be well and in good health.
I will be posting some topics from The Atheism Delusion on this page. It will be beneficial, God willing.
The Friedmann Models:
General relativity predicts a non-static universe. Einstein was trying to avoid this issue by adding the cosmological constant to his equation. So along with many physicists at the time, Einstein used to believe that the universe was static and steady. A static and steady universe must collapse upon itself if there is no force or energy to counteract the attraction of matter and the cosmological energy.
However, Russian physicist Alexander Friedmann resolved this issue in a different way. Instead of adding the cosmological constant to the equation, he found a solution: an unsteady model of the universe that concurs with general relativity. Einstein eventually embraced the Friedmann solution and admitted that he was wrong to add the cosmological constant and assume that the universe was static. However, it will be mentioned that later on dark energy was discovered, which works against gravity, meaning it matches the job of the cosmological constant in gravity’s counteraction of matter and energy.
Afterwards, three models of an unsteady universe were completed, commonly referred to as the Friedmann models. This opened the door to the expanding universe, which has a beginning. The Friedmann models had predicted that the universe is expanding before Edwin Hubble used the results of galaxy observations to discover that the frequency of light that galaxies emit shifts toward the color red, and this shift increases the further away they are. According to the doppler effect, this means they are moving away from each other at an increasing rate.
The Friedmann models are:
The first model: The curvature of the universe is positive like the surface of a sphere, and if it is expanding, it will eventually contract due to gravity, and its expansion will not continue forever.
The second model: The curvature of the universe is negative like the surface of a hyperbolic paraboloid or a horse saddle, and if it is expanding, its expansion will continue forever.
The third model: The curvature of the universe is zero, or let’s say it is flat. If it is expanding, its rate of expansion will slow down, approaching but never actually reaching zero. This means it will slow down, but never completely stop expanding. In this type of universe, the positive energy provided by matter equals the negative energy provided by gravity.
All Friedmann models predict that at the beginning of the universe, the distance between the galaxies was zero, meaning the size of the universe was zero and its density was infinite. This means that the Friedmann models built on the theory of relativity state that the universe started from a point at which the theory of general relativity itself collapses. This point is called a point of singularity, at which the big bang began.