Hubble, a NASA space telescope, continues to bring us breathtaking pictures of the planets, stars, and galaxies. Since its launch and deployment by the space shuttle Discovery in 1990, it has revolutionised astronomy.
According to NASA, a recent infrared survey from the Hubble Space Telescope, which looked for this so-called "intracluster light," sheds new light on the mystery. The new Hubble observations suggest that these stars have been wandering around for billions of years, and are not a product of more recent dynamical activity inside a galaxy cluster that would strip them out of normal galaxies.
"The survey included 10 galaxy clusters as far away as nearly 10 billion light-years."
The observations also showed that intracluster space in the early universe was illuminated by the weak, diffuse light of lone stars; these stars had been travelling alone for a very long period.
"This means that these stars were already homeless in the early stages of the cluster's formation," said James Jee of Yonsei University in Seoul, South Korea. His findings have been released in Nature magazine's January 5 issue.
"We don't exactly know what made them homeless. Current theories cannot explain our results, but somehow they were produced in large quantities in the early universe," said Jee. "In their early formative years, galaxies might have been pretty small, and they bled stars pretty easily because of a weaker gravitational grasp."
"If we figure out the origin of intracluster stars, it will help us understand the assembly history of an entire galaxy cluster, and they can serve as visible tracers of dark matter enveloping the cluster," said Hyungjin Joo of Yonsei University, the first author of the paper.
Galaxies and clusters of galaxies are held together by dark matter, the universe's invisible framework.
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