The latest episode of Cosmos, devoted to explaining the nature of space, time, and the speed of light, presented a stunning case in point. For as host Neil deGrasse Tyson explained, if creationists were right about the extreme youth of the universe, then we wouldn’t even be able to see the vast majority of the stars in the sky.
The logic is unavoidable: Light travels at a fixed speed of 186,000 miles per second. Because of this, many objects in the universe are many “light-years” away from us, where a light-year is simply the distance light travels in the space of the year. As an example, Tyson presented one particular object, the Crab Nebula, which just happens to be 6,500 light years from Earth. This means that when we look at it, what we’re actually seeing is the nebula as it was 6,500 years ago.
The Crab Nebula is far away, but not that far: It is actually still part of our own Milky Way galaxy. But the fact that it happens to be 6,500 light-years off has a particular significance for creationists who believe the world is exactly that same age.
Read the full, original story: The Latest “Cosmos” Episode Has the Best Argument Yet Against Creationism