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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Big Bangs Made Way for Solar System
9 October 2001 7:00 pm
Our solar system sits inside a bubble of space that is mysteriously empty. Now, an astronomer suggests that the area was blasted clean by several massive explosions from stars in a cluster that has since migrated away from us. The theory, reported in the 10 October issue of Astrophysical Journal, could settle a long-standing debate about the origin of the so-called Local Bubble and offer clues about how many such bubbles exist inside our galaxy.
In the mid-1970s, astronomers began to recognize that the space around the solar system has a density less than 1% of normal. Many believed that only powerful explosions from dying stars, or supernovae, could explain this interstellar void. But there are so few stars nearby that it's highly unlikely that three or more would explode within the required few million years, and those low odds have mystified scientists.
Now, astronomer Jesús Maíz-Apellániz of the Space Telescope Science Institute in Baltimore, Maryland, may have found the answer. Maíz-Apellániz analyzed the movements, velocities, and present positions of stars in the Scorpius-Centaurus cluster, just outside the bubble. Extrapolating back, he found that 2 million to 8 million years ago, dozens of the stars were inside what's now the Local Bubble. That number was high enough for Maíz-Apellániz to estimate that about six exploded, demolishing almost everything nearby. In the same time period, the sun and other stars moved in, although the bubble remains relatively empty.
"It's the most likely theory I've heard in the last 5 or 10 years," says Steven Snowden, an astronomer at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Snowden believes that Maíz-Apellániz's theory could help astronomers determine the frequency of such bubbles-giving us a better understanding of what our galaxy looks like.