STEADY STATE THEORY

The Big Bang is not the only proposed theory concerning our universe's origin. In the 1940s a competing hypothesis arose, called the Steady State theory. Some astronomers turned this idea simply because, at the time, there wasn't enough information to test the Big Bang. British astrophysicist Fred Hoyle and others argued that the universe was not only uniform in space-an idea called the Cosmological Principle - but also unchanging in time, a concept called perfect cosmological principle. This theory didn't depend on a specific event like the Big Bang. Under the Steady State theory, stars and galaxies may change, but on the whole the universe has always looked the way it does now, and it always will. 

The Big Bang predicts that galaxies recede from 1 another, space becomes progressively emptier. The Steady State theorists admit that the universe is expanding, but predict that new matter continually comes to life in the space between the receding galaxies. Astronomers propose that this new material was made up of atom of hydrogen, which slowly coalesced in open space to form new stars.

Naturally, continuous creation of matter from empty space has met with criticism. How can you get from nothing? The idea violates a fundamental of law of physics: the conservation of matter. According to this law, matter can neither be created nor destroyed, but only converted into the forms of matter or into energy. But skeptical astronomers have found it hard to directly disprove the continuous creation of matter, because the amount of matter formed under the Steady State theory is so very tiny: about one atom every billion years for every several cubic feet of space.

The Steady State Theory fails, however, in 1 important way. If matter is continuously created everywhere, then the average age of stars in any section of the universe should be the same. But astronomers have found that not to be true.

Astronomers can figure out how old a galaxy or star is by measuring its distance from Earth. The farther away from the Earth an object is, the longer it has taken light from the object to travel across space and reach Earth. That means the most distant objects we can see are also the oldest.

For example, take a quasar's, the small points of light that give off enormous amounts of radio energy. Because the light from quasars i shifted so far to the red end of the spectrum, astronomers use Hubble's law to calculate that this powerhouses lie at a great distance from Earth, and hence are very old. But quasars exist only at these great distances -  none are found quasars. If the Steady State theory were true there ought to be but young and old quasars. Since astronomers haven't found quasars that formed recently, they conclude the universe must have changed over time. The discovery of quasars has put the Steady State theory on unsteady ground.