A piece of oxygen-darkened amber was said to hold a particular arachnid, but it wasn't clearly visible. Scientists made a surprising discovery when a computed tomography scan was able to produce a finely detailed three-dimensional image of a hunting spider. But if the amber is actually 49 million years old, as is claimed, why hadn't it completely darkened long ago?

For many creatures, embryonic development involves the amazing unfolding of a single cell into an animal with billions of cells, each with a specific structure and function. How does a small ball of identical dividing cells know when to start or stop its growth, as well as when or where (not to mention how) to begin differentiating into various types of tissues?

More than 80 varieties of fish, amphibian, and reptile mothers are able to lay eggs that have not been fertilized and yet produce offspring. In a process called "parthenogenesis," these eggs hatch little clones of the mother, which in turn lay clone eggs themselves. Could this remarkable mode of unisexual reproduction have evolved?

Because of the amount of time it takes distant light to reach earth, the farther away an object is, the further back in time it appears to be.

Jupiter's moon Io may have a very short name, but it definitely has the highest volcanic activity of any object in the solar system. Littered with volcanoes, its unique surface sports a massive active volcano named Loki whose lava output exceeds that of all of earth's volcanoes put together.