Seven tiny specks of interstellar space dust captured by Stardust, a NASA probe, have agency scientists excited about the origins of the universe. It is the first time that elements from beyond the solar system have been captured and brought back for analysis. Within the makeup of these particles could lie information scientists can extract to understand humanity’s place in the ever-evolving cosmos.
Launched on Fegruary 7, 1999, Stardust’s primary mission was to intercept the comet Wild 2 and collect samples from the cloud of melted ice and dust, or coma, that shrouded its nucleus. A comet’s coma is formed as its orbit approaches the sun.
The captured dust samples were then returned to earth via a separate capsule for analysis by scientists. That part of the mission was completed when the capsule parachuted to earth on January 15, 2006. Stardust continued its mission by intercepting another comet, Tempel 1. The spacecraft ceased operations in March 2011.
While Stardust was collecting comet samples on one side, the other side, facing away from the comet, was able to collect bits of interstellar dust. The captured space dust came from the direction of the constellation Ophiuchus. It has taken scientists years to find and analyze the seven dust particles that may have originated from outside the solar system. If confirmed, it will mark the first time interstellar material has ever been returned to earth by a space vessel.
These tiny motes are bits of rocks filling the vast void of space. They have their origin in supernovas and other major universal events. Containing elements like oxygen, nitrogen and carbon, they are the precursor to planetary life. Andrew Westphal, planetary scientist from the University of California at Berkeley, stated, “Instead of looking at interstellar dust with telescopes, now we get to look at samples…with microscopes.”
Each mote of NASA’s captured interstellar space dust has its own, individual characteristics suggesting their origins might be as diverse as the universe itself. Some of the motes are small and dense, while others are larger and fluffier. Identifying the objects collected and determining their interstellar origin has been a major undertaking.
Preliminary study of the particles revealed surprising information. Some 0f them contained sulfides, elements scientists did not expect to find. Olivine, a mineral derived from silicon, magnesium and iron was also found. These elements, probably modified by interstellar space, were thought to come from distant stars. Other particles containing aluminum were discounted since the metal is not found in the interstellar medium.
All of the dust motes are extremely small, weighing about one trillionth of a gram. To analyze these tiny particles researchers used powerful synchrotrons. Synchrotrons accelerate electrons close to the speed of light to gather information about elements at the molecular level. Since synchrotrons are the size of a small mall, they cannot be transported into space. It highlights the need for missions like Stardust to capture materials and return them for in-depth analysis.
NASA is continuing to search the cosmos for evidence of living organisms and universal evolution. Rosetta Stone, a current joint space operation with the European Space Agency (ESA), is linking up with Comet 67P/C-G, 251 million miles from earth. The spacecraft will deploy a module onto the comet in hopes of capturing interstellar dust and organic material that could shed light on the origins of biological life and the universe itself.
By Hans Benes