Three specks of matter captured by the NASA spacecraft Stardust may be stardust that has just entered our solar system.
© JPL/NASASPECKS - As a spacecraft completed its ride through the solar system, it swung past Earth and detached a capsule, above, containing the collected particles.
"They have all the hallmarks of interstellar dust," said Andrew Westphal of the Space Sciences Laboratory at the University of California, Berkeley.
Dr. Westphal reported the first speck in March, and he described the second and third on Friday at a meeting of the Meteoritical Society in Manhattan. Each speck is about one-25,000th of an inch across.
The third is particularly intriguing. It is rich in carbon, raising the possibility that it is full of the molecules that could serve as the building blocks for life.
The Stardust's primary mission was to bring back bits of a comet that it passed in 2004, but scientists also hoped that it would also trap some interstellar particles within a wispy concoction known as aerogel that served as a cosmic dust collector.