By South China Morning Post | Created at 2024-11-30 12:01:23 | Updated at 2024-11-30 16:42:11
4 hours ago
Chinese scientists have achieved a breakthrough in submarine detection by successfully creating a radio-emitting source in the sky using high-energy microwave synthesis technology.
According to the researchers, this virtual signal source is capable of emitting electromagnetic waves continuously while travelling at close to the speed of light.
For an observer on Earth, the wavelength of these electromagnetic waves, emitted by a source moving away at such high speeds, would significantly expand. This would result in a reduction of the signal frequency, similar to the redshift – the move towards the red end of the electromagnetic spectrum – of some distant stars.
These extremely low-frequency (ELF) electromagnetic waves have the capability to penetrate seawater, making it possible to detect submarines hiding hundreds of metres beneath the surface.
This is a “disruptive technology”, according to the research team led by Li Daojing with the National Key Laboratory of Microwave Imaging of the Chinese Academy of Sciences, in a peer-reviewed paper published this month.
When facing signals with frequencies as low as 100Hz, the radar cross-section (RCS) of a nuclear submarine in seawater can reach up to 88 square metres (947 square feet). This means that underwater target detection can be achieved using just “common magnetic detectors”, Li and his colleagues wrote.
