Science A–Z

A physicist who helped transform our understanding of light, space, time, and gravity. His 1921 Nobel Prize recognized his explanation of the photoelectric effect.

The leading scientific account of the universe's early development: space has been expanding from an extremely hot, dense early state for about 13.8 billion years.

The control center of the nervous system. Its networks of neurons receive information, coordinate the body, form memories, and make thought possible.

The fifth planet from the Sun and the largest in our solar system. It is a gas giant with powerful storms, faint rings, and many moons.

A physicist and chemist who pioneered research on radioactivity, helped discover polonium and radium, and became the first person awarded two Nobel Prizes.

The fourth planet from the Sun. Iron minerals give its surface a rusty red color, and evidence shows that liquid water flowed there long ago.

The smallest planet and the closest to the Sun. Its cratered surface experiences extreme temperature changes between day and night.

The eighth and most distant major planet from the Sun. This cold blue ice giant has some of the fastest winds measured in the solar system.

Our solar system has eight planets: four rocky inner worlds, two gas giants, and two ice giants. All orbit the Sun.

A map of the chemical elements arranged by atomic number. Elements in the same column often share important chemical behavior.

The seventh planet from the Sun. This blue-green ice giant rotates on its side, probably because of a massive collision early in its history.