Deep blue facts

You won't believe what they found in the Pacific: 10 incredible sea facts

Image: Isabel Noschka

As you probably know, the oceans cover about 70% of the Earth's surface. That's huge! However, humans have explored only about 5% of the ocean. Just imagine what fascinating—and possibly terrifying—creatures might be hiding down there! If you're ready to learn 10 little-known facts about the ocean, keep reading.

Image: Fernando Jorge

If you think the Andes are the longest mountain range on the planet, you're only partially right! At about 5,500 miles long, the Andes are the longest mountain range on Earth’s surface. However, the ocean hides a giant over 40,000 miles long. That’s right—the Mid-Ocean Ridge, which lies entirely underwater, is actually the longest mountain range on Earth!

Image: Vincent Camacho

In the Pacific Ocean, about 124 miles east of the Mariana Islands, lies the famous Mariana Trench. It's more than just a trench—it's the deepest oceanic trench on Earth. In fact, it's even deeper than Mount Everest is tall! You might be thinking, "Wait, what?" Well, Everest rises an impressive 29,032 feet above sea level, but the deepest point of the Mariana Trench, known as the Challenger Deep, plunges to about 36,000 feet below sea level.

Image: nadhem benmbarek

If you say "older than dinosaurs" to refer to something that happened a long, long time ago, you could also say "as old as sea sponges." That’s because sea sponges—simple, invertebrate sea creatures—have existed on this planet since before the dinosaurs, and they’re still here! As some of the first multicellular organisms on Earth, they’ve been around for about 600 million years!

Image: James Thornton

We all know that trees and plants give us oxygen through photosynthesis. But did you know that land-based plants contribute only about 20 to 30% of the Earth's oxygen? That’s right—the majority, around 70%, comes from the ocean! This oxygen is produced through photosynthesis by marine organisms like phytoplankton, algae, and cyanobacteria.

Image: Mikhail Preobrazhenskiy

Frogfish aren’t particularly distinguished by their beauty, but their eccentric appearance is not the only strange thing about them. When it comes to eating, they have a really hard time! Why? It happens that these creatures are carnivorous and feed mainly on other fish and crustaceans. But here's the thing: they don't have teeth! So, they have no choice but to swallow their prey whole.

Image: Thomas Vimare

Despite being teeming with life, even containing thousands of species that humans have yet to discover, the ocean also has areas where there’s virtually nothing. What do we mean? We're talking about the so-called "dead zones" of the ocean—those parts where the amount of oxygen is so low that almost no form of life can survive!

Image: Veronica Reverse

Among the many surprises that can be found under the sea is the Great Barrier Reef, recognized as the largest living structure on the planet.

Located off the coast of Australia, it stretches over 1,400 miles—that's about the same distance as between New York City and Dallas! In fact, it’s so large that it can even be seen from space. Amazing, isn’t it?

Image: Heidi Bruce

The ocean is home to incredible creatures, and among the most fascinating is the mimic octopus. As its name suggests, this extraordinary animal has the ability to adopt a wide variety of shapes.

The mimic octopus can change its color, texture, and form to blend in with its surroundings, imitating different surfaces. But what’s even more surprising is its ability to mimic not just the appearance, but also the behaviors of other marine animals!

Image: Matt Paul Catalano

Water is incredibly powerful—and surprisingly fast! It has been proven that tsunamis—those giant waves caused by underwater earthquakes—can travel at speeds of 500 to 600 miles per hour, roughly the same speed as a jet plane. That’s why tsunamis are so dangerous and destructive when they reach land.

Image: Kris-Mikael Krister

Do you know what nudibranchs are? These creatures are soft-bodied marine mollusks are known for their stunning colors. But their appearance isn’t the only amazing thing about them—some types of nudibranchs are even solar-powered! What does that mean? Well, these incredible creatures can harness the sun’s rays to produce energy, much like plants do.

The ultimate leadership system

Decoding the chain of command: 10 main U.S. military ranks explained

The structure of the United States military relies on a hierarchy designed to maintain operational discipline and distribute leadership across every level of command. Examining 10 main U.S. Military ranks in sequential order reveals the language behind the names.

The rank of Private represents the entry-level enlisted tier in the U.S. Army and U.S. Marine Corps. At this level, service members focus on basic training, mastering tactical skills, and executing orders issued by superior officers.

Etymologically, "private" is short for "private soldier", designating an individual without public office or independent military command. Historical records note that some of the earliest documented uses of the term in the American military context appear in the personal correspondence of George Washington.

A Corporal is responsible for leading small tactical units, such as fireteams or squads. Corporals oversee the daily discipline, appearance, and fundamental skills training of junior soldiers.

The word derives from the French corporal, which stems from the Latin caput (meaning "head"). Over time, the term was influenced by the Latin corpus ("body") and the French military term corps, blending roots for "head" and "body" into the modern word corporal.

A Sergeant is a key frontline leader who typically commands a squad or section and directly supervises daily operations. Sergeants hold direct responsibility for troop welfare, equipment maintenance, and tactical execution.

The word shares its Latin root (serviens, meaning "servant") with the word servant. In medieval times, a "sergeant at arms" served as an armed retainer to a feudal lord. As military structures modernized, the sergeant evolved into the link between commissioned officers and enlisted troops.

The rank of Lieutenant serves as the entry point for commissioned leadership. Lieutenants typically command platoons consisting of 16 to 40 service members alongside an experienced platoon sergeant.

The term comes directly from the French lieu tenant, which literally translates to "place holding". A lieutenant is a placeholder or deputy tasked with standing in for or assisting a superior commander.

A Captain typically commands a company, battery, or troop consisting of 60 to 200 service members. Captains represent one of the oldest military designations in the English language, used as a general term for a military leader since the 1400s. Derived from French and rooted in the Latin caput ("head"), a captain is the "head" of an organized military unit.

A Major serves as a field-grade officer, often functioning as a battalion executive officer or primary staff supervisor. Interestingly, the rank of major is a historical abbreviation of sergeant major. During the 16th and 17th centuries, a sergeant major was a commissioned field officer ranking above a captain. As the boundary between non-commissioned officers and commissioned officers solidified in the 1700s, the "sergeant" prefix was dropped, leaving "Major" as a distinct officer rank.

A Colonel commands brigade-sized formations (1,500 to 3,200 soldiers) or fills critical senior staff positions. The title originates from the Italian colonnello, meaning the leader of a column (colonna) of troops. The unusual English pronunciation ("kernel") occurred because English borrowed the word from French, which had adopted the Italian word but altered its pronunciation, while English retained the French spelling.

A Brigadier General is a one-star general officer who commands a brigade or serves as a deputy commander for a division. The title derives directly from brigade, denoting an operational military unit composed of multiple regiments or battalions.

A Major General is a two-star general who typically commands a force of 10,000 to 15,000 personnel. This rank has a historical quirk: despite a Major ranking above a Lieutenant, a Major General ranks below a Lieutenant General. This is because the rank was originally called sergeant major general before the 1700s. Because a "sergeant major general" was subordinate to a "lieutenant general", the order remained intact even after "sergeant" was removed from the title.

A General is a four-star officer holding the highest operational rank in peacetime. Four-star generals command unified combatant commands, geographic theaters, or serve as service branch chiefs of staff. Rooted in the Latin generalis (meaning "pertaining to all" or "universal"), the title signifies overarching authority across all branches and arms of command.