NASA Simulator Creates Stardust on Earth from Scratch
NASA scientists have successfully replicated, here on Earth, the processes that form interstellar dust in the atmosphere of a red giant star.
A team led by Farid Salama of the agency's Ames Research Center in Moffett Field, Calif. created a device, called the Cosmic Simulation Chamber (COSmIC), to better understand the types of grains that form around dying stars.
Dust grains that form in the outer layers of dying stars, such as those in the red giant phase, are catapulted into space and (after millions of years) can lead to the formation of planets.
"The harsh conditions of space are extremely difficult to reproduce in the laboratory, and have long hindered efforts to interpret and analyze observations from space," Salama said in a news release. "Using the COSmIC simulator we can now discover clues to questions about the composition and the evolution of the universe, both major objectives of NASA's space research program."
In the past, the inability to reproduce space conditions in the gaseous state has prevented scientists from identifying unknown matter. But the COSmIC device changes the game. It recreates the harsh vacuum-like conditions prevalent in deep space, including ultraviolet and visible radiation from nearby stars, temperatures under -270 degrees Fahrenheit (-168 degrees Celsius), and a diffuse soup of interstellar ions and molecules.
"We now can for the first time truly recreate and visualize in the laboratory the formation of carbon grains in the envelope of stars and learn about the formation, structure and size distribution of stellar dust grains," said Cesar Contreras of the Bay Area Environmental Research Institute.
"This type of new research truly pushes the frontiers of science toward new horizons, and illustrates NASA's important contribution to science."
The team started with small hydrocarbon molecules that it expanded in the cold jet spray in COSmIC and were then exposed to an electrical discharge. NASA detected and characterized the large molecules that are formed in the gas phase from these precursor molecules with highly sensitive detectors. Then, individual grains were gathered and imaged with Ames' Scanning Electron Microscope.
With these techniques, researchers were able to characterize dust nanoparticles only 10 nanometers in diameter, dust grains between 100 and 500 nanometers wide, and aggregates of grains up to 1.5 micrometers in size.