Science News Roundup: Climate change may have stimulated plankton bloom behind Thai mass fish die-off: expert; How to kill a star? Astronomers see a 'demolition derby' scenario and more

They suspect the two doomed stars were neutron stars, which pack roughly the mass of our sun into a sphere only the size of a city. Study reveals how immune system of astronauts breaks down Evidence is growing about the many ways that traveling in the microgravity environment of space tampers with the human body, with new research showing how it dials down the activity of genes in white blood cells crucial to the immune system.

Following is a summary of current science news briefs.

Stonehenge-like 4,000-year-old sanctuary discovered in Netherlands

Archaeologists have discovered a 4,000-year-old sanctuary made up of ditches and burial mounds in the central Netherlands that they believe may have served a similar purpose to Stonehenge. Like the famous stone circle in southern England, the sanctuary - which was as big as at least three soccer fields and built with soil and wood - was built to align with the sun on the solstices.

Climate change may have stimulated plankton bloom behind Thai mass fish die-off: expert

Climate change might have stimulated a plankton bloom that caused thousands of dead fish to wash up along a 3- to 4-kilometre stretch of beach in Thailand's southern Chumphon province, an expert said. Thon Thamrongnawasawat, deputy dean of the Faculty of Fisheries at Kasetsart University, attributed the fish deaths on Thursday to the bloom - a natural occurrence that lowers oxygen levels in the water and causes fish to suffocate.

How to kill a star? Astronomers see a 'demolition derby' scenario

Astronomers have spotted an immensely energetic explosion emanating from an ancient galaxy, apparently triggered by a type of star destruction hypothesized for decades but never before observed. You might call it stellar death by demolition derby. Researchers said the gamma-ray burst they observed may have been caused by the collision of two compact stars in the densely packed and chaotic environment near a supermassive black hole at the center of this elliptically shaped galaxy. They suspect the two doomed stars were neutron stars, which pack roughly the mass of our sun into a sphere only the size of a city.

Study reveals how immune system of astronauts breaks down

Evidence is growing about the many ways that traveling in the microgravity environment of space tampers with the human body, with new research showing how it dials down the activity of genes in white blood cells crucial to the immune system. A study involving 14 astronauts who spent 4-1/2 to 6-1/2 months aboard the International Space Station found that gene expression in these cells, also called leukocytes, quickly decreased when they reached space and then returned to normal not long after returning to Earth, researchers said on Thursday.