Notes of a lecture on starlight and time. Do they present an insurmountable problem for biblical creationists? The lecture was given August 1st, 2015. See Age and Reason Seminar Adelaide for details.
Here is the problem. The universe is truly vast in size, in fact, tens of billions of light-years in size. One light-year is about 10 trillion kms. It is the distance light travels in one year. By taking a literal history from Genesis chapters 5 and 11 you can calculate that the universe is only about 6000 years old. If so, how does starlight get to earth from a distance greater than 6000 light-years? Shouldn’t we only be able to see to a distance of 6000 light-years in the universe?
Is this a brick wall? Does it mean the bible must be wrong? Distances are billions of light-years. Surely that must mean light took billions of years to travel here from the distant cosmos? How do you explain that?
Ok, lets first look at some simple maths.
Distance = Speed x Time
So if you drive your car a distance of 100 kms and travel at 50 km/hr it will take you 2 hours. 10 billion light-years represents a distance in the Universe to some of the most distant galaxies like those pictured here in what is called the Hubble Ultra-Deep Field 2014.
This is an image taken with the Hubble Space Telescope. The galaxies are between 5 and 10 billion light-years away. Light travelling at 1 light-year/year over that distance should take 10 billion years to get to earth. Shouldn’t it?
Let’s not argue over the distances in the cosmos. They are truly vast and even if the assumed distances were in error such that they were really 100 times less it would not solve the problem. Secondly there is the speed of light. Has it changed over time? If so, that could be a place to look for an answer. But it is a speed limit in the known Universe. And finally, there is the time it takes light from the distant cosmos to travel to earth, which is related to how we actually measure that time. We might also ask in reference to the biblical statements on the age of the Universe, by which clocks is that age measured? But biblical creationists are not the only ones with a light travel time problem. Continue reading