On January 15, 2006, the Stardust spacecraft’s sample return capsule parachuted gently onto the Utah desert. Nestled within the capsule were precious particles collected during Stardust’s dramatic encounter with comet Wild 2 in January of 2004; and something else, even rarer and no less precious: tiny particles of interstellar dust that originated in distant stars, light-years away. They are the first such contemporary interstellar dust particles ever collected in space and returned to Earth for study.

Before they can be studied, though, these tiny interstellar grains have to be found. As we have discovered since we started the Stardust@home project in 2006, this is not easy. Unlike the thousands of particles of varying sizes collected from the comet, scientists originally estimated that Stardust would collect only around 45 interstellar dust particles. After a thorough search of about one-third of the collector, we have so far found only four particles that appear to be interstellar. So they are incredibly rare and precious. They are tiny only about a micron (a millionth of a meter) in size! These miniscule particles are embedded in an aerogel collector 1,000 square centimeters in size. To make things worse the collector plates are interspersed with flaws, cracks, and an uneven surface. All this makes the interstellar dust particles extremely difficult to locate.

If we were doing this project twenty years ago, we would have searched for the tracks through a typical laboratory microscope of the era. Because the view of the microscope is so small, we would have had to move the microscope more than 1.6 million times to search the whole collector. And in each field of view, we would have had to focus up and down by hand to look for the tracks. This is so much work, that even starting twenty years ago, we would still be doing it today!

This is where you come in:

Since we cannot do this by ourselves, we are asking for help from talented volunteers like you from all over the world. Of course, we can’t invite hundreds of people to our lab to do this search-we only have two microscopes! To find the elusive particles , therefore, we are using an automated scanning microscope to automatically collect images of the entire Stardust interstellar collector at the Curatorial Facility at Johnson Space Center in Houston. We call these stacks of images focus movies. All in all there will be nearly a million such focus movies. These are available to Stardust@home users like you around the world. You can then view them with the aid of a specialVirtual Microscope (VM) that works in your web browser.

Together, you and thousands of other Stardust@home participants will find the first pristine interstellar dust particles ever brought to Earth.

In recognition of the critical importance of the Stardust@home volunteers, the discoverer of an interstellar dust particle appears as a co-author on any scientific paper by the Stardust@home team announcing the discovery of the particle. The discoverer also has the privilege of naming the particle! Each particle, as it is discovered, will be given some kind of alpha-numeric identifier (an address of sorts) for book-keeping purposes. But the name that people will actually call each particle will be given to it by its discoverer. For example, Bruce Hudson of Ontario, Canada, discovered our first candidate interstellar dust track. Its official NASA “phone number” is “I1043,1,30,0,0” – which is very hard to remember and doesn’t exactly roll off the tongue. So we asked Bruce to give it a name to publish it by, and he decided on “Orion”, and then later “Sirius” for the accompanying upstream particle that was discovered very nearby. Bruce was featured in a recent article in Nature on Citizen Science projects. To also recognize the efforts of our volunteers who work hard, but may not have found a particle, we will invite the top-ranked volunteers to come visit our lab in Berkeley for a special tour. (Unfortunately, we are legally precluded from covering travel expenses.)

“If we knew what it was we were doing, it would not be called research, would it?”
– attributed to Albert Einstein

How to participate:

First, you will go through a web-based training session. You must pass a test to qualify to register and participate. After passing the test and registering, you will be able to login to the virtual microscope. The VM will automatically connect to our server and download focus movies. The VM will work within your web browser, under your control. You will search each field for interstellar dust impacts by focusing up and down with a focus control.

The VM downloads and displays these images, so that you can do just what someone sitting at real microscope would do: focusing up and down in each movie to look for tracks. To use the VM you will need a relatively fast internet connection, and the latest version of just about any web browser. To find out more about the system requirements for the VM visit our Tech FAQ.

Some things to keep in mind while searching…

The instructions for searching with the VM are simple. Click on the tracks if you find them, or click on “No Track.” If any part of the FOV does not focus beneath the surface of the aerogel then click on “Bad Focus.” If you see something else of possible interest that does not appear to be a flaw in the aerogel or a particle track, you should click on that as well.

Each focus movie will be viewed by many different people. When a volunteer identifies the focus movie as either having or not having a particle track the movie will be given a score. The score the focus movie receives will be weighted by the score of the volunteer.


Stardust@home volunteers (aka “Dusters”) accumulate two types of individual scores: “Power Score” and “Skill Score.” Your scores are based on random VM calibration movies (also called “Power Movies”). For more information on Power Movies and how your Power and Skill scores are calculated, please see the Help page. Please note, once you sign-up to take part in Stardust@home, you will receive feedback e-mails about Power Movies you’ve missed. The emails include what the missed values were, and a link to see a picture of exactly where each calibration track was located so that you can study at your leisure what we want you to be looking for. This information will also be available to you on your “My Events” page while dusting – even if you choose to opt-out of receiving the feedback emails. Please be aware that you WILL miss Power Movies that are essentially impossible – even we miss those! But if you are routinely missing tracks with low values (less than 30 or so), we encourage you to go back and review the training. Everyone, even long-time veteran dusters, can benefit from a refresher.

“If you’re not having fun, you’re not doing it right.”
– Jim Westphal

The best attitude for this project is this: Have Fun! If you’re not having fun, stop.

As with any research project, the outcome is uncertain. You may be lucky enough to find an interstellar dust particle. You may find an interplanetary dust particle. You may find something entirely unexpected. Or you may search for hours or days and find nothing at all. We simply don’t know what will happen. This unpredictability is what makes science fun!

The search will take several years to complete. Our automated microscope at the Johnson Space Center can scan about one tile of aerogel from the Stardust interstellar dust collector tray per day. There are 130 tiles in total. We may have false starts (in fact, we already have), where we discover a problem and have to rescan one or more tiles. For example, once we find a dust track, we may decide to change the lighting conditions or the scanning parameters so that the scans are better. Please be patient with us!

Don’t be discouraged if you don’t find something right away, or even later in the project if many interstellar dust grains have already been found. We don’t know a lot about interstellar dust grains. But one thing that we do know is that they are diverse. Even if 99 interstellar dust grains are eventually identified near the end of the project, it may be that the 100th is the most important–the rare grain that turns out to be the key to understanding interstellar dust! Again, please be patient, and remember that the most important thing is to have fun.

This is a completely new approach to doing research. We are in utterly new territory—no one has ever done a project like this before, so we have no experience with it. As with any research project, we will be learning as we go. We will make mistakes (we guarantee it). We ask in advance for your patience. All we can promise is that we will do our best.

We will rely on your feedback to improve things as we go.
If you have ideas, suggestions, or questions, please use our message board to communicate those to us. We cannot guarantee that we will agree with every recommendation that you make. If we do, and it is practical to adopt it, we will do so. We will acknowledge those who make specific, constructive and polite recommendations on our website, even if we don’t adopt them. We may not be able to respond personally to every message.