Slowing stars

Chilean telescope shows star formation is almost over

New collaborative study using telescopes in Chile and Hawaii suggests that the universe will only increase in stellar density by 5 percent from present-day value. 

Wednesday, November 28, 2012 Category: Education
The astronomers studied levels of alpha particles that are emitted from Hydrogen atoms and are indic The astronomers studied levels of alpha particles that are emitted from Hydrogen atoms and are indicators of star formation. Photo courtesy of Anttler/Flickr / Fotopedia.


A new study involving the European Southern Observatory’s (ESO) Very Large Telescope (VLT) in northern Chile’s Atacama Region has provided the most comprehensive evidence yet to suggest that star formation in the universe is sputtering to a halt.


This graph shows the slowing rate of star formation over time. Note the rapid increase in stellar density during the universe’s younger years. Image courtesy of Sobral et al.

This graph shows the slowing rate of star formation over time. Note the rapid increase in 

stellar density during the universe’s younger years. Image courtesy of Sobral et al.



The study, led by astronomer David Sobral using the UK Infrared and Subaru telescopes in Hawaii as well as the VLT, suggests that the rate of star formation in the universe is at just 3 percent of its historic top rate.


“You might say that the universe has been suffering from a long, serious ‘crisis’,” Sobral said in a statement. “Cosmic GDP output is now only 3 per cent of what it used to be at the peak in star production.”

Using a sample size 10 times larger than previous similar studies, Sobral and his colleagues analyzed imagery of the universe from 2, 4, 6, and 9 billion years ago, searching for alpha particles associated with star formation.


The current standard model holds that the first stars began to form around three hundred years after the start of the universe, or 13.4 billion years ago. Sobral’s study backs up previous findings that indicate a massive glut of star formation between 11 and 9 billion years ago, when about half of the universe’s stars formed, with the other half forming in the 9 billion years that followed.


According to the study, published in the Royal Astronomical Society’s Monthly Notices, if the rate of star formation continues this downward trend, the universe has already produced 95 percent of all the stars that will ever form.


"While these measurements provide a sharp picture of the decline of star formation in the universe, they also provide ideal samples to unveil an even more fundamental mystery which is yet to be solved: Why?" Sobral said.


Due to its almost non-existent humidity and clear skies, the Atacama is the planet’s premier location for astronomy. Chile is home to almost half the world’s telescope infrastructure, and this is set to increase to over two thirds by 2018.

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