A revolutionary plan to turn the Earth into a giant observatory!

Fiber optic cables run across the oceans to power communication systems, and scientists believe this vast network of infrastructure could be used to observe the Earth’s surface from below.

In particular, the 1.2 million kilometers (over 745,000 miles) of existing fiber optic cable could be combined with satellites and other remote sensing tools to observe the entire globe “from above and below” in real time.

According to the authors of this idea, in this way it is possible to track storms and earthquakes, as well as ships and whales passing through the seas. It is possible to use the network in the task of detecting broken pipelines.

“This global observatory has the potential to be a game-changer in ocean and earth sciences,” says geophysicist Martin Landru from the Norwegian University of Science and Technology (NTNU).

Monitoring will be carried out using acoustic sensors of fiber-optic cables. Any bends in cables can be picked up by sound waves or real waves and interpreted to measure movement.

The team demonstrated this last year while tracking whales in the Arctic. Over the course of 44 days in 2020, scientists were able to detect more than 800 whale sounds over a 120-kilometer underwater cable. They also detected a major storm at a distance of 13,000 kilometers (8,078 miles).

All of this was made possible by a setup known as distributed acoustic sensing (DAS) and a device called an interrogator. The interrogator sends a pulse of light down the fiber optic cable, which then detects any bends and accurately measures them.

“This technology has been around for a long time,” says Landru. “But it has taken a huge step forward in the last five years. So now we can use it to monitor and measure acoustic signals up to 100 meters away.” up to 200 kilometers. It’s new.”

And there are limitations: the results obtained by the system contain a lot of noise, which means that the signals are more difficult to capture than, for example, with seismographs. This is where other sensors, such as satellites, come into play to provide additional context.

It is also a constantly updated technology. Currently, DAS researchers cannot “see” the legacy components inside fiber optic cables used to transmit signals, but researchers are working hard to overcome this limitation.

The team is also keen to emphasize that its global surveillance network will complement other systems, not replace them. Since these cables are very wide, the potential number of results can be overwhelming.

“The DAS whale detection and observation experiment demonstrates an entirely new use for this type of fiber optic infrastructure, resulting in superior and unique science,” says Landru.

The study was published in the journal Scientific Reports.

Source: Science Alert