Dr. Gasser Hathout, July 17, 2005
Universe now remain expanding. With time they go further and further apart. It's like a blowing balloon up. It is the result of big bang. We now take it for granted but at that time it was a considered a scientific heresy.
When Albert Einstein pretty much formulated the theory in 1912, 1915, 1917 and 1919, he sensed the universe could not be stable and either it is expanding or compressing, which is the theory of general relativity. At that
time scientists considered that the universe is static. Hence in order to solve this confusion, Einstein introduced the cosmological constant to force the equation to be constant.
In 1929, Edward Hubble, after whom the Hubble telescope was named, made an amazing discovery that the universe is expanding based on observations and not scientific theory. Hubble went on to win the Nobel Prize for this discovery. Einstein learnt about Hubble's discovery and conceded saying that it was the biggest mistake of his entire life that he did even though he knew that the universe is expanding.
"And the firmament, We constructed with power and skill and verily We are expanding it." (Quran, 51:47)
The arabic word "moosiAAoona" in some tafsir books is translated as "the vastness of space", which means the universe is static but I think the more appropriate translation of this word is that "we are actively expanding it".