According to the latest finding by the ICRAR scientists, all galaxies rotate once every billion years, no matter how big they are.
The Earth turning around on its pivot once gives us the length of a day, and a total circle of the Earth around the Sun gives us a year.
Although, it’s not Swiss watch precision. Be that as it may, paying little mind to whether a universe is huge or little if you could sit on the extreme edge of its disk as it spins, it would take you about a billion years to go all the way around.
Professor Gerhardt Meurer from the UWA said, “By using simple maths, you can show all galaxies of the same size have the same average interior density. Discovering such regularity in galaxies really helps us to better understand the mechanics that make them tick—you won’t find a dense galaxy rotating quickly, while another with the same size but lower density is rotating more slowly.”
Scientists found evidence of older stars existing out to the edge of galaxies. They also found a significant population of older stars along with a thin smattering of young stars and interstellar gas.
Professor Meurer said, “This is an imperative outcome since knowing where a cosmic system closes implies we cosmologists can restrain our perceptions and not sit around idly, exertion and PC handling power on examining information from past that point.”
“Because of this work, we now know that galaxies rotate once every billion years, with a sharp edge that’s populated with a mixture of interstellar gas, with both old and young stars.”
Professor Meurer said that the next generation of radio telescopes, like the soon-to-be-built Square Kilometre Array (SKA), will generate enormous amounts of data, and knowing where the edge of a galaxy lies will reduce the processing power needed to search through the data.
“When the SKA comes online in the next decade, we’ll need as much help as we can get to characterize the billions of galaxies these telescopes will soon make available to us.”
Journal Reference
- Gerhardt R Meurer, Danail Obreschkow, O Ivy Wong, Zheng Zheng, Fiona M Audcent-Ross, D J Hanish. Cosmic clocks: a tight radius–velocity relationship for H i-selected galaxies. Monthly Notices of the Royal Astronomical Society, 2018; 476 (2): 1624 DOI: 10.1093/mnras/sty275