Twinkle twinkle, little star: Scientists convert star 'twinkles' into sound waves
Stars appear to twinkle from Earth due to starlight bending as it passes through our atmosphere. However, stars also have a "twinkle" that isn't an optical illusion.
This twinkle is caused by rippling waves of gas on the stars' surfaces, and it's currently imperceptible to existing ground-based observatories.
A team led by scientists at Northwestern University has developed the first 3D simulations of energy rippling from a massive star's core to its outer surface, a press statement reveals. Using their simulations, the scientists could determine how often stars should perform these real twinkles.
The researchers, who published their findings today, July 27, in a paper in the journal Nature Astronomy, could also convert these rippling waves into sound waves, allowing listeners to hear what this "twinkling" sounds like.
Twinkle twinkle, little star
The new audio representation of star twinkling is a word-first that stemmed from the team's investigation into gas waves emanating from the cores of massive stars.
"Motions in the cores of stars launch waves like those on the ocean," Northwestern's Evan Anders, who led the study, explained in the press statement.
"When the waves arrive at the star's surface, they make it twinkle in a way that astronomers may be able to observe," Anders continued. "For the first time, we have developed computer models which allow us to determine how much a star should twinkle as a result of these waves. This work allows future space telescopes to probe the central regions where stars forge the elements we depend upon to live and breathe."
Stars have a convection zone where gases churn, pushing heat outward toward the star's surface. This convection zone is found at the core of giant stars at least 1.2 times the mass of our sun.
"Convection within stars is similar to the process that fuels thunderstorms," Anders explained. "Cooled air drops, warms, and rises again. It’s a turbulent process that transports heat."
The process also creates waves that cause starlight to dim and brighten periodically. The team set out to simulate the processes occurring within these massive stars' cores, shedding new light on how these waves cause the stars to twinkle.
"Stars get a little brighter or a little dimmer depending on various things happening dynamically inside the star," Anders said. "The twinkling that these waves cause is extremely subtle, and our eyes are not sensitive enough to see it. But powerful future telescopes may be able to detect it."
The sounds of stars and space
Anders and his team also used their simulations to generate sound. The real waves have too low a frequency for human ears to hear, so the researchers increased their frequencies to make them audible.
The eerie sounds can be heard via the following link.
The researchers explained that the waves make different sounds depending on the region of a star they come from. For example, waves emanating from the core of a large star make sounds similar to a ray gun from a sci-fi movie. However, as that wave travels to the star's surface, the sound is altered, shifting into a sound reminiscent of a low echo reverberating in an empty room.