Light Year
A light year is a unit of distance used in astronomy to measure how far light travels in one year. Light moves extremely fast—about 299,792 kilometers per second—so in one year, it travels roughly 9.46 trillion kilometers (or about 5.88 trillion miles). Light years help scientists express the huge distances between stars and galaxies. For example, the nearest star to Earth, Proxima Centauri, is about 4.24 light years away. The term “light year” can be confusing because it sounds like a measure of time, but it actually measures distance.
Fathom
A fathom is a unit of length traditionally used to measure the depth of water. It equals 6 feet or approximately 1.8288 meters.
Originating from the Old English word fæðm, meaning "to embrace" or "outstretched arms," the fathom was based on the average distance between a person's outstretched arms. It has been widely used by sailors and navigators to estimate sea depths and underwater distances.
Key facts:
1 fathom = 6 feet
1 fathom ≈ 1.8288 meters
1 fathom = 2 yards
Though modern sonar and electronic instruments now measure depth more precisely, the fathom remains a traditional unit in nautical contexts, especially in maritime charts and historical references.