There are a lot of scientific papers out there. One estimate puts the count at 1.8 million articles published each year, in about 28,000 journals. Who actually reads those papers? According to one 2007 study, not many people: half of academic papers are read only by their authors and journal editors, and the average number of readers for a published scientific paper is only 0.6.

Brain freeze, or sphenopalatine ganglioneuralgia is a form of headache commonly associated with consumption (particularly quick consumption) of cold beverages or foods such as ice cream.

Scientists have discovered that sunflowers can pull radioactive contaminants out of the soil.

A salt is an ionic compound that results from the neutralization reaction of an acid and a base.

An eclipse is an astronomical event that occurs when an astronomical object is temporarily obscured, either by passing into the shadow of another body or by having another body pass between it and the viewer.

A nebula is an interstellar cloud of dust, hydrogen, helium and other ionized gases. Contrary to fictional depictions where starships hide in nebulae as thick as cloud banks, in reality a nebula that is barely visible to the human eye from Earth would appear larger, but no brighter, from close by.

A mushroom (or toadstool) is the fleshy, spore-bearing fruiting body of a fungus.

The Universe is all of time and space and its contents.

The human heart has four chambers, which are the left and right atria and the left and right ventricles.

Absolute zero is the lowest temperature that is theoretically possible, at which the motion of particles that constitutes heat would be minimal. It is zero on the Kelvin scale, equivalent to -273.15°C or -459.67°F.