Carbon is a chemical element with the symbol C and atomic number 6.

Coordinated Universal Time (UTC) is the primary time standard by which the world regulates clocks and time.

Earth is the third planet from the Sun in our solar system and the only known celestial body to support life.

The Wikipedia page for Global Positioning System (GPS) provides an overview of the satellite-based navigation system developed by the United States Department of Defense.

Helioseismology, a term coined by Douglas Gough, is the study of the structure and dynamics of the Sun through its oscillations.

Helium is a chemical element with the symbol He and atomic number 2.

The ionosphere is a region of Earth's upper atmosphere, extending from about 60 kilometers (37 miles) to 1,000 kilometers (620 miles) above the planet's surface.

Kelvin is a unit of temperature widely used in the scientific field.