In a first, scientists create loudest possible sound

In a new experiment, scientists have produced what may be the loudest possible sound underwater with the help of X-ray lasers.

A team from SLAC National Accelerator Laboratory used X-ray laser to generate extremely loud underwater sound by blasting tiny jets of water, creating sound pressures above 270 decibels.

Sound is measured on decibel scale, at the lowest end of which is the limit of human hearing. In comparison, sound of normal conversations is at 55 decibels, a chain saw at 100 decibels, jet taking off 330ft away is at 130 decibels, and the sound of a rock concert is 150 decibels, as per New Atlas.

However, in air, a sound can’t get higher than around 194 decibels, but in water it’s about 270. For creating the sound, the researchers blasted micro-jets of water thinner than a hair strand, with Linac Coherent Light Source (LCLS), an insanely powerful X-ray laser that can do things like heating water to 100,000°C in less than a millionth of a millionth of a second, reported Science Alert.

When the short X-ray pulses hit the water it vaporized, it generated a shockwave. The shockwave then traveled through the jet and formed copies of itself in a ‘shockwave train’ made up of alternating high and low pressure zones – in short, an extremely loud underwater sound.

Once the sound intensity went above a certain threshold, the water broke down and turned into small vapor-filled bubbles, which immediately collapsed in a process known as cavitation. Also, since the pressure in the X-ray-generated sound wave is just below the break-apart threshold, it is as loud as an underwater sound can be.

The team believes that by better understanding how these shockwave trains work, it may be possible to find ways to protect miniature samples undergoing atomic-scale analysis inside water jets from damage, which would be of great help in the development of better drugs and materials.