From: cleoabram
Despite the ocean covering 71% of Earth’s surface, our understanding of its floor is surprisingly limited [00:00:42]. While Google Maps may suggest precise topography, this is largely inaccurate [00:00:10]. We possess significantly less detailed knowledge of the ocean floor than we do of the surface of Mars [00:00:14].
Current Mapping Resolution
The resolution of maps for different celestial and terrestrial bodies highlights the disparity:
- Mars: Mapped to a resolution of 5 meters per pixel [00:00:19].
- Earth’s Land: Mapped to approximately 30 centimeters [00:00:25].
- Most Oceans: Mapped at a resolution of 1.5 kilometers, which is 300 times less detail than land maps [00:00:28].
This lack of detail is a significant problem, as the ocean is constantly used for various purposes, including laying internet cables, global trade, and food sources [00:00:32].
Challenges of Ocean Mapping
Mapping the ocean is inherently difficult due to its immense depth and the properties of water [00:01:43].
- Pressure: At 10 meters deep, the pressure is an entire additional atmosphere [00:01:54]. The pressure at the Titanic’s depth (3800 meters) is over 350 atmospheres, capable of instantly collapsing submersibles [00:02:30].
- Darkness: Light cannot penetrate beyond a thousand meters, leaving the vast majority of the ocean in complete blackness [00:02:13].
- Depth: The deepest known natural point, Challenger Deep, is 10,935 meters (6.8 miles) deep, deeper than Mount Everest is tall [00:03:08].
How Current Maps are Made
Since light cannot reach the ocean floor, current maps often rely on indirect methods [00:00:55].
Satellite Gravity Data
Much of the topography seen on platforms like Google Maps is derived from satellite gravity data [00:03:55]. This method, explained by marine scientist Steve Hall, leverages the subtle variations in the ocean’s surface caused by gravitational pull [00:04:00]:
- The ocean surface is not perfectly flat; it subtly reflects the shape of the seabed below [00:04:16].
- A deep trench causes a slight dip in the sea surface above it, while a mountain creates a tiny bulge [00:04:24].
- Satellites send radar pulses to measure the height of the water surface, then estimate the seafloor’s shape [00:04:38].
While this method provides a good approximation, it lacks precision, leading to blurry, low-detail images when attempting to zoom in [00:04:58]. Many of these maps are based on “educated guesswork” [00:05:10].
Historical Evolution of Ocean Floor Mapping Techniques
Early mapping efforts utilized acoustic waves.
- Sonar: Devices developed before the 1940s could send acoustic waves into the water and record the time it took for them to bounce back [00:05:28].
- Marie Tharp: In the 1940s, Marie Tharp transformed raw sonar measurements into the first ocean floor maps, revealing mountains and valleys [00:05:37].
- She manually connected data points from narrow lines of sonar along shipping routes using colored pencils to create contours and 2D profiles [00:07:08].
- Working with Bruce Heezen, she sketched what parts of the ocean might look like, eventually compiling these into early published maps, such as one from 1957 [00:07:32].
- However, these maps still required significant “filling in the blanks” due to sparse data [00:08:12].
Modern Sonar Advancements
Today, sonar remains crucial, but its capabilities have vastly improved.
- Instead of single beams, modern sonar devices send thousands of beams in a wide fan, covering several kilometers at once [00:08:37]. This allows for mapping much larger areas in greater detail [00:08:47].
Importance of Detailed Seabed Mapping
Detailed maps of the ocean floor are critical for numerous reasons:
- Navigation: Better navigation for deep ocean activities like laying internet cables [00:09:02].
- Safety: Predicting tsunamis, storms, and sea level rise [00:09:07].
- Resource Management: Understanding the ocean for new renewable energy sources [00:09:11].
- Crisis Response: During the search for MH370, entire mountain ranges and valleys were discovered that had never appeared on maps, highlighting the risk of navigating uncharted territory [00:09:16].
Seabed 2030 Initiative
An international collaboration called Seabed 2030 aims to map the entire ocean floor in detail by the year 2030 [00:09:45].
- Resolution Targets:
- Unknown areas: 800 meters resolution [00:09:54].
- Higher traffic areas: A few meters resolution [00:10:00].
- Data Sources: The project aggregates data from diverse sources, including oil and gas companies, environmental groups, and militaries (with some limitations on sensitive areas) [00:10:05].
- Technological Advancements: Seabed 2030 heavily relies on cutting-edge ocean technology [00:10:40]:
- Robots: Unmanned and autonomous underwater vehicles (AUVs) are used for “mowing the lawn” — systematically collecting measurements in a grid pattern, a task too tedious for human crews [00:10:45].
- AI: Artificial intelligence is being developed to enable robots to autonomously identify and investigate interesting features with higher accuracy [00:11:17].
Since the project began, the percentage of the ocean floor with detailed maps has increased from 6% to 25% [00:11:24].
Ethical Considerations
Some concerns exist that more detailed maps could lead to destruction, such as deep-sea mining for minerals [00:11:35]. However, Steve Hall argues that the lack of a map is not a barrier to such activities [00:11:43]. He emphasizes that “you can’t manage what you haven’t measured,” and maps provide a level playing field for understanding and responsible decision-making [00:11:48]. It is humanity’s responsibility to use new knowledge wisely [00:12:01].
The ability to map our environment has historically been the first step toward understanding it and using it for the better [00:12:10]. Exploring the ocean is likened to the collaborative efforts on the International Space Station, where countries overcome political differences for the sake of exploration and science [00:12:25]. Through technology, curiosity, and grit, humanity is finally able to visualize and interact with this alien world on our own planet [00:12:44].