What is the Universe? Is it empty of all matter and without a Creator?
The Universe cannot be created or otherwise measured, for it is infinite and eternal. According to quantum mechanics, the Universe consists of a vast vacuum, which is neither known nor unknown. It is said that the laws of conservation of energy govern the behaviour of the Universe; thus, the laws of thermodynamics also state that the Universe cannot be destroyed.
The present-day Universe consists of space-time, which cannot be seen by the naked eye, as it is fuzzy and void of any visible matter.
The whole Universe consists of empty space, and space-time is made of what is known as “dark energy”. The cosmos seems to be static, as it contains no moving parts. It is the source of dark energy that makes the Universe move, and the motion that brings about changes in the temperature of the “atoms” of the cosmos.
Astronomers have detected a number of galaxy groups and clusters, which are relatively close together, which they term as “galactic clusters”.
These clusters are extremely hot and dense, emitting highly radio waves and ultraviolet radiation. They are the result of merging millions of stars, which are extremely hot and extremely dense, which collectively emit X-rays and gamma rays. Astronomers cannot see through the hydrogen atoms of these clusters, but they can detect their effects on the very hot, extremely dense gas clouds. These clouds reach a temperature of ten times the Earth’s average temperatures.
The present-day Universe was created in about a billion years from a preceding explosion of solar-type stars.
This explosion produced more than three times as much matter as the Sun. The amount of dark matter is about ten times the amount of solar matter. This makes the present-day Universe extremely heavy, with an overall density about ten times that of the Sun. Because of this heavy concentration of dark matter, the present-day Universe is very dense, with about four hundred times the density of water.
The present-day Universe is expanding at a rate of about seven hundred thousand miles a second. Most astronomers think that the future expansion will continue at this rate, with a speed of about a hundred miles a second, until it is over in about a billion years. Although the present-day Universe is expanding, we still don’t know how the expansion will affect the various scales of the Universe. Some researchers are of the opinion that the expansion will slow down when the dark matter becomes less dense, while others think that it will speed up. Scientists don’t quite know which theory is correct.
The present size of the Universe is not very well-guessed by us. We have telescopes to measure the distance and other such ways. But there are some interesting clues which are not very strong and can be compared with our present-day knowledge only. We know that the largest objects in the Universe, like the stars and planets, are relatively close to their own milieu (the space surrounding them), whereas very distant objects like the galaxies are outside our milieu. And if we place these objects inside of a large halo of gas, they get even closer to us.
Another way to measure the present-day size of the Universe is by looking at the amounts of radiation coming from objects which originated far away, at great distances from the Earth.
If we observe that the radiation produced by stars is quite a lot stronger than the radiation produced by the Sun, and that the radiation emitted by objects at great distances from the Earth is much dimmer, then we can estimate the amount of distance that objects of a given mass can from the rest of the sky. This technique, called the cosmic background radiation, was earlier used to study the properties of the first particles of the Universe, which are very similar to those of the Sun. By comparing the measured strength of the cosmic background radiation with the value obtained from calculations based on general relativity, astronomers came to the conclusion that the Sun was very near its own galaxy.
The other way to calculate the amount of distance from a star is to take into consideration the orbital elements of the planets of the Solar System.
Planets such as Jupiter and Saturn revolve around their own axes quite rapidly, while the comets move much slower. Moreover, astronomers have calculated the values of the orbital periods of the planets in our solar system, and have deduced that the average distance from the Earth to the innermost planets of the Solar System, namely Earth, Jupiter, Saturn, Uranus, Neptune, Pluto, and Epsilon Masses, is about 3.6 astronomical units. The calculation is therefore not far off, if we take into account the fraction of the solar radius for each planet, and the fraction of the annual mean orbital period for the planets. Hence, the fraction of the solar radius and the fraction of the annual mean orbital period of the planets indicate the sizes of the Solar System, the present-day volume of the Universe, and the number of ancient planetary systems in the Universe.