Bruce Hudson, from Ontario in Canada, is just such a citizen scientist and he has discovered what scientists believe is the first piece of interstellar dust that was captured by NASA'a Stardust spacecraft. The NASA mission was primarily sent to catch dust streaming from Comet Wild 2 and return it to Earth for analysis, but scientists also set up the Stardust Interstellar Dust Collector (SIDC) to capture interstellar dust. The spacecraft landed back on Earth in 2006 and scientists have been analysing the data ever since.
The dust collector is made of aerogel and as an interstellar particle hits the collector it will form a signature trail wider than itself – imagine firing a bullet into a swimming pool filled with jelly - before either being stopped in its tracks or flying straight through. The scientists estimate they will find as few as 45 interstellar dust particles embedded in the collector. “Finding them will be like searching for 45 ants on a football field while searching one 5 cm x 5 cm square at a time.” laments the Stardust@home website.
This is why a part of the research has been outsourced to enthusiasts worldwide. Stardust@home is a website where anybody in the world can help find these particles of stardust, with some 27,000 people having already joined. The images taken of the aerogel are not really flat pictures but rather “focus movies” in that they are a complete slice of the material with the ability to focus in and out using their dedicated online viewer, or “virtual microscope”. Your mission, should you choose to accept it, is to look at each slice, focus in and out as if operating a real microscope and report back should you find one of those elusive specks of interstellar dust or, more likely, a signature trail. The prize is that you get to name the particle. Bruce Hudson named the previously plain “particle 30” as “Orion”. “So far this particle is unique... if we drop it on the floor, it will cost $300m to get another one.” says a nervous Dr Andrew Westphal, from the University of California, Berkeley.
The above image shows the surface of an aerogel slide. The "track" looks unimportant and the random dirt is in focus. Adjusting your "virtual microscope" to look under the surface (below) the dirt becomes out of focus but the important interstellar dust track is now clear. You've found space dust! Or at least the trail of one!
But why is all this important? “All the heavy atoms in this room were in interstellar dust...” enthuses Don Brownlee, from the University of Washington, who is considered the pioneer of interstellar dust research “... so we want to know what this stuff is.” According to current theory, such heavy atoms are formed when stars explode but once the particles have cooled down they could be flying through interstellar space for billions of years. They are thus an echo of past star-bursts and can help explain how stars and planetary systems evolve.
Dr Westphal is, however, keeping his feet on the ground just in case this discovery proves, on further analysis, to be some other space debris that can also be seen in numerous of their slides. "It is very fine-grained material, which is what you'd expect for interstellar dust. It has an elemental composition which is consistent with what you would expect for interstellar dust. And it has a composition for other elements which are not inconsistent, but a bit surprising." he explains to the BBC. The researchers have so far analysed magnesium, aluminium, iron, chromium, manganese, nickel, copper and gallium from the particles. When the research paper eventually gets published, our citizen scientist Bruce Hudson will also get his name up in bright lights – well, as a joint author anyway.
So it's time to roll up your sleeves, don that lab-coat (purely optional) and get a feel for what it's like to be a research scientist: paying close attention to detail, getting tired and frustrated from hours staring at apparently similar images, as well the excitement of actually finding something unique – something nobody else has ever seen! In the words of the Stardust@home website, “The best attitude for this project is this: Have Fun!”