Final answer:
Recent discoveries challenging the Young Earth Creationist view include dinosaur embryos with soft eggshells over 200 million years old, the transitional fossil Archaeopteryx, and evidence of a mass extinction caused by a cosmic collision.
Step-by-step explanation:
Some recent discoveries that have challenged the Young Earth Creationist (YEC) view include the discovery of dinosaur embryos and their soft eggshells by a team led by Mark Norell, suggesting that dinosaurs reproduced in a way similar to modern birds over 200 million years ago. Additionally, the fossil of Archaeopteryx provides evidence of shared ancestry due to its combination of reptilian features and feathers, indicative of evolutionary transitions. The presence of a crater and evidence of a cosmic collision explain the mass extinction event, further supporting a timeline that exceeds the YEC timeframe.
Most fossils found are not of complete organisms, which presents a challenge for scientists; they have responded by using technology and comparative anatomy to piece together the full picture of prehistoric life. Among the significant pieces of evidence used in the 1800s to suggest Earth is very old was the stratification of rock layers. Lastly, it is clear that relative to the length of time life has been on Earth, modern humans have appeared very recently. These discoveries and lines of evidence support the extensive geological and evolutionary time scales, opposing the YEC view.