Researchers Just Filled A Major Gap In HIV's Evolutionary History

Researchers know that HIV jumped from apes and monkeys to humans on multiple occasions, in the form of HIV-like viruses called simian immunodeficiency viruses (SIV). To date, 11 out of 13 of these cross-species transmissions have been accounted for. On Monday, researchers identified the final two. » 3/02/15 2:35pm Yesterday 2:35pm

Can You Solve One Of Archimedes' Most Challenging Puzzles?

Archimedes was the greatest mathematician of antiquity. He was also a lover of puzzles, which he would devise and pose to his contemporaries. This week, we present you with two versions of what is arguably Archimedes' most challenging puzzle ever. » 3/01/15 1:05pm Sunday 1:05pm

Rats remember acts of kindness, and then reciprocate. A study published this week in Biology Letters showed rats remember who is nice to them and return the favor later. National Geographic calls it "the first evidence of direct reciprocation in nonhumans." We're not so sure about that last part, but it's an… » 2/25/15 6:00pm Wednesday 6:00pm

Aerogel Sure Makes A Funny Sound, For A Supermaterial

If you're familiar with aerogel, you know that it's one of the lowest-density materials on Earth. But even if you're versed in this supermaterial's physical properties, you've probably never thought about what aerogel sounds like. This video answers that question. » 2/25/15 2:40pm 2/25/15 2:40pm