The fact that distant starlight can be seen from Earth has always been a major problem for the young Earth idea. Because the speed of light is finite, what you are actually seeing when you look at an object is an image of that object from the past. "From the past" here has a few caveats regarding the relativity of our concept of the past, the future, and now. In the BBC Horizonprogram What Time Is It? physicist and former pop-synth player Brian Cox suggested that, as information cannot travel faster than light, and that time and space are relative, it can be considered that that the stars actually are what they look like "now", in a manner of speaking. Either way, though, the bottom line is still the same; the light has travelled a certain distance, for a certain time, before arriving on Earth to be seen by our eyes or telescopes. We can use this data to put a minimum time on the existence of the universe, by looking at how long some light has been travelling for.

On Earth, the delay caused by the speed of light is incredibly minor — when you look at an object a mile away, the light has been travelling for five microseconds. When you look at the Sun, you are seeing light that has been in transit for 8.3 minutes. It's more noticeable with sound and distant objects, but only because the light from things such as distant explosions or jet fighters is so much faster. There's still a delay and transit time for the information that says whatever made the light/sound must have been around that long ago to produce it.

On the cosmic scale of things, this delay is far from minor and really is noticeable. When astronomers look at the closest star to Earth (Alpha Centauri), which is roughly four light years away, they are seeing the star as it was four years ago from our perspective. When astronomers look at objects in the region of space known as the "Hubble ultra deep field", they are seeing the stars there as they were over ten billion years ago. Light we are receiving from these fields has been travelling for ten billion years, and the universe must have, therefore, existed long enough for that transit time to take place.

Therein lies the problem for young Earth creationism; if the universe is only 6,000 years old, how can objects billions of light years away — and therefore billions of years old — be seen?

Many places on Earth show evidence of erosion taking place over very long time periods. The Grand Canyon, for instance, would have taken millions of years to form using the normal rate of erosion seen in water.^[9] Nevertheless, Young Earthers insist it was cut in a few years following the Great Flood - but in order for this to happen the rocks of the Kaibab Plateau would have needed to have the solubility of granulated sugar, rather than the more solid stone that it's made of.^[10]VenomFangX of YouTube claimed that the Grand Canyon would have formed in about "5 minutes", which at the very least would require the water to travel 5-6 times the speed of sound.^[11]

In the case of the Yakima River in Washington State between Ellensburg and Yakima, the river meanders with many oxbows typical of a slow-moving river on a plain, yet it is set within a deep canyon with visible layers of erosion. The only possible explanation is that the pre-existing river maintained its original bed as slow tectonic forces caused the surrounding land to rise underneath and around it.

Ice layering is a phenomenon that is almost universally observed in ice sheets and glaciers where the average temperature does not rise above freezing.

Annual differences in temperature and irradiation cause ice to form differently from year to year, and this generates alternating layers of light and dark ice, much like tree rings. This method is considered a relatively accurate way to measure the age of an ice sheet, as only one layer will form per year. While there have been a few cases where several layers have formed per year, these incidents do not challenge the ability of ice layering to provide a minimum age, as these false layers can be discerned from the real thing upon close inspection.

Currently, the greatest number of layers found in a single ice sheet is over 700,000, which clearly contradicts the idea of an Earth less than 10,000 years old. Even if one were to assume an absurdly high average of ten layers per year, the age demonstrated by this method would still be far greater than that suggested by young Earth creationists.^[16]

Nevertheless, the minimum age of the Earth identified by these means is 160,000 years. (+/- 15,000 years.)

Deoxyribonucleic acid (DNA), the universal carrier of genetic information, is present in all organisms while they are alive. When they die, their DNA begins to decay under the influence of hydrolysis and oxidation. The speed of this decay varies on a number of factors. Sometimes, the DNA will be gone within one century, and in other conditions, it will persist for as many as one million years. The average amount of time detectable DNA will persist though is somewhere in the middle; given physiological salt concentrations, neutral pH, and a temperature of 15 °C, it would take around 100,000 years for all the DNA in a sample to decay to undetectable levels.^[21]

If fossils of the dinosaurs were less than 6,000 years old, detectable fragments of DNA should be present in a sizable percent of dinosaur fossils, especially in the Arctic and Antarctic regions where the decay of DNA can be slowed down 10-25 fold. A claim that soft tissues in a Tyrannosaurus fossil had been recovered in 2005^[22] have since been shown to be mistaken,^[23] supporting the idea that dinosaur fossils are extremely old.^[24]

The formation of permafrost (frozen ground) is a slow process. To be consistent with the young earth creationist model, which states that all sediment was deposited by the global flood, there would have to be absolutely no permafrost present at the end of the flood, because any permafrost that was present at the moment of creation would have been melted during the flood.

Because earth is a good insulator and permafrost forms downward from the surface, it would have taken much more than the few thousand years allotted by creation theory to produce some of the deepest permafrost. In the Prudhoe Bay oil fields of Alaska, the permafrost which extends over 600 meters into the ground is believed to have taken over 225,000 years to reach present depth