Most astrophysicist generally agree that the universe is 12.5 billion years old or thereabouts. Agreed? This age is determined by the observation of the most distant light detected in the universe, which reaches us on earth after traveling 12.5 billion light-years (side: a light-year is not a measurement of time, but rather of distance- i.e., 1 light-year is the distance that light travels in 1 year. Simple). Given the following observation, that is, of light that has reached the earth after traveling 12.5 billion light-years, astrophysicists deduce the age of the universe to be 12.5 billion years old.
For me (admittedly, a laymen in astrophysics), there is an inherent flaw with this line of argument; namely, that in order for us to observe light that has traveled for 12.5 billion years, there has to be a distance of 12.5 billion light-years spanning between the earth and the source of this long-traveling light. However, matter does not travel at the speed of light, and in fact, the expansion velocity of all of the observable matter in the universe spawned by the Big Bang is roughly 1-3% the speed of light, depending on the matter at hand. So, here lies the predicament: Since the distance between us and the source of the most distantly observed light is expanding at a velocity of between 1-3% the speed of light, this means that it would take somewhere between 412.5 billion years to 1,250 billion years in order to produce a total distance of 12.5 billion light-years.
EDIT: Spelling mistake. heh.
For me (admittedly, a laymen in astrophysics), there is an inherent flaw with this line of argument; namely, that in order for us to observe light that has traveled for 12.5 billion years, there has to be a distance of 12.5 billion light-years spanning between the earth and the source of this long-traveling light. However, matter does not travel at the speed of light, and in fact, the expansion velocity of all of the observable matter in the universe spawned by the Big Bang is roughly 1-3% the speed of light, depending on the matter at hand. So, here lies the predicament: Since the distance between us and the source of the most distantly observed light is expanding at a velocity of between 1-3% the speed of light, this means that it would take somewhere between 412.5 billion years to 1,250 billion years in order to produce a total distance of 12.5 billion light-years.
EDIT: Spelling mistake. heh.