Allah The Allmighty says :
( 22-47 ) < And surely a day with your Lord is as a thousand years of what you number.>
It's mean that a Day by Allah is 1000 years in our reckoning in relation with the revolution of the Moon around the Earth ( it is the Hegire year) or the revolution of the Earth around the Sun ( Gregorian year).
And Allah says :
[70.4] To Him ascend the Angels and the Spirit in a day the measure of which is fifty thousand years.
In this verse of the Sura 'The way of Ascent' ( it is the Way which take the Angels from the Earth to the Heaven after having excecuted the duties necessary for the Life of our Planet and the Kosmos. We can note that Allah doesn't say "fifty thousand years of what you number" because the day in question in this verse is a time measure of a Gods day ( which each day is 1000 years in our reckoning ) and this day is the age of the Universe which all events of our life from heaven to earth ascend to Him.
Let's convert these God's Years in our norms :
50,000 * 365.2422 (days in human year) = 18,262,110 Allah's Days.
One Day by Allah is corresponding 1000 years of our reckoning, therefore the Age of the Universe is :
18,262,110 * 1,000 = 18,262,110,000 years, that's to say that the age of the Universe is around 18, 1/4 Billions years. This number correspond exactly of the above article . After more than 14 centuries, Science and particularly Professor Jean-Claude Batelere of the "College de France" states that it is now a certitude that the Universe is 18 billions years old .
Note that others Secrets are hidden in these two verses.