The Tunguska event was a large explosion that occurred near the Tunguska River, in where is now Russia. The explosion occurred at an altitude of 5–10 kilometres (3–6 mi) by a stony asteroid that is believed to have burst in the air rather than hitting the surface.

Since the 1908 explosion, there have been an estimated 1,000 scholarly papers (mainly in Russian) published on the Tunguska explosion. In 2013, a team of researchers led by Victor Kvasnytsya of the National Academy of Sciences of Ukraine published analysis results of micro-samples from a peat bog near the blast epicenter showing fragments that may be of meteoric origin.

Estimates of the energy of the blast range from as low as three to as high as 30 megatons of TNT. The energy of th ...

A dog searching for a lost child is typically given an item of clothing to smell. But what does that scent “look” like?

To find out, scientists tested 48 dogs, half of which had special police or rescue training. In a laboratory room, the scientists slid each dog’s favorite toy across the floor to a hiding place, while the dog waited in another room. One researcher then brought the dog to the testing room and pointed at the starting point of the odor trail and told the dog, “Look for it! Bring it!” In one trial, the dog found either its favored toy or a different item.

Many of the surprised dogs continued searching for the toy used to lay the scent trail—an indication that they had a mental representation of what they expected to find. Bot ...

Phytochemicals are compounds in foods found in plants that are thought to be beneficial to health. More than 5000 different types have been identified, and several studies have linked their intake to reduced risk for cardiovascular disease, cancer, diabetes, Alzheimer’s, cataracts, and age-related decline. While they may be beneficial, they are not considered nutrients (substances necessary to sustain life), thus no daily recommended intakes have been established.

A list of five popular phytochemical families are listed below, along with their health claims and food source.

Carotenoids:

Includes: Alpha-carotene, beta-carotene, lutein, lycopene, zeaxanthin, etc.

Health Claims: Diets with foods rich in these phytochemicals may reduce the risk of ...