Conventional geology assumes that different rock layers represent different periods of time. Paleontologists assess the age of fossilized creatures by the rock layers in which they are found. So, a fossil found in a lower rock layer is considered to have lived in a much earlier time than one found in a higher ("younger") stratum.

When waters are murky, how do seals find fish? They don't have a sonar apparatus like whales, and yet they somehow hunt successfully in the dark.

The human genome has become a leading area of biological investigation. Its massive amounts of data have been digitized, which allows the information to be more easily studied. Much of genomic function remains a mystery, so new discoveries are common--and often quite surprising to the researchers making them.

Hopes of finding life on Mars have been consistently dashed by data clearly showing that the planet's surface would be extraordinarily hostile to anything resembling a living cell. Scientific studies have demonstrated that conditions there would quickly put an end to any incipient life form.

Turinah, a woman who lives in south Sumatra, claimed to be 157 years old in the latest Indonesian census. She has no records to prove her claim, but other evidence suggests she might be telling the truth. Is it biologically feasible that a person born in 1853 could still be alive in 2010?