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USS Thresher underway at sea on July 24, 1961

In 1963 USS Thresher disappeared during deep-diving tests 220 miles east of Cape Cod with 129 people aboard and the loss forced the U.S. Navy to rebuild submarine safety around SUBSAFE

One hundred twenty-nine people were aboard USS Thresher when the nuclear-powered attack submarine was lost in the Atlantic on April 10, 1963. The loss remains the deadliest accident in U.S. submarine history. It also left a lasting technical and human legacy, because the Navy rebuilt crucial parts of its approach to submarine design, repair, testing,…

Marie Tharp with Al Ballard and Marty Weiss during the 1968 USNS Kane expedition

Oceans Explainer

In 1956, Marie Tharp published a hand-drawn North Atlantic seafloor map after recognizing a V-shaped rift in six depth profiles and its alignment with earthquake patterns helped reshape the evidence for a moving ocean floor

Pacific Ocean seen from space by the Suomi NPP satellite

Oceans Explainer

Pacific Ocean: Size, depth, currents and the Ring of Fire

NASA satellite visualization of chlorophyll concentrations across the Atlantic Ocean

Oceans Explainer

Atlantic Ocean: The growing basin that moves heat around Earth

View of the vast ocean and horizon from an offshore platform under cloudy skies

Oceans Explainer

In 1962 engineers launched a 355-foot research platform that flooded its tanks until 300 feet pointed straight down, turning FLIP into a nearly motionless ocean laboratory that served scientists for 61 years before its 2023 retirement

Deep-sea manned vehicle for oceanographic research and rescue operations

Oceans Explainer

In 1974, Alvin and two French submersibles descended into the Mid-Atlantic Ridge, made 44 dives and collected 100,000 photographs and 3,000 pounds of rock while giving scientists a close view of how new ocean crust takes shape

Illuminated HMS Belfast with Tower Bridge in the backdrop at night in London

Oceans Explainer

In 1872 HMS Challenger left Portsmouth with six scientists and 243 crew members, traveled nearly 127,000 kilometers over almost four years, made 492 depth soundings and returned with a global record that helped establish modern oceanography

NOAA bathymetric map of Monterey Bay and its submarine canyon

Oceans Explainer

In 1857, James Alden found a deep valley in Monterey Bay while sounding from the Coast Survey Steamer Active, revealing the first known seafloor canyon before sonar existed and giving mariners an early glimpse of the hidden terrain beneath California’s central coast

In 1857, a set of depth measurements in Monterey Bay produced a surprise that no sailor could see from the deck. James Alden, commanding the Coast Survey Steamer Active, traced a deep valley running through the bay. The feature would become known as Monterey Canyon and NOAA records describe it as the first known seafloor…

Technology Explainer

In 1958 USS Nautilus slipped beneath the Arctic ice on a secret second attempt, carried 116 people across the geographic North Pole and emerged near Greenland after nuclear propulsion solved the endurance problem that had stopped earlier submarines

For the 116 people aboard USS Nautilus, the Arctic Ocean offered no reliable way to surface, communicate, or turn around quickly. Thick ice sealed off the sea above them. In August 1958, the nuclear-powered submarine passed beneath that ceiling and reached the geographic North Pole, opening a route that had long resisted undersea travel. The…

NASA satellite composite centered on the Indian Ocean, southern Africa and Madagascar

Oceans Explainer

Indian Ocean facts

The Indian Ocean helps set the rhythm of life for hundreds of millions of people. Its seasonal winds help shape rainfall over East Africa, the Indian subcontinent and Southeast Asia. Its warm waters store heat, feed powerful storms and carry water between the tropics and the Southern Ocean. It is also a busy marine crossroads.…

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