Did you know? The University of Wisconsin–Madison is the headquarters for the IceCube Neutrino Observatory, a science experiment located in Antarctica at the South Pole! Almost 400 scientists and engineers from all over the world work together on this project, the biggest, strangest telescope in the world.
Instead of looking at light from stars in the night sky like traditional telescopes, IceCube continuously looks for mysterious particles called neutrinos that are created in outer space. It is over a cubic kilometer in size, and most of it is buried underground.
Neutrinos are tiny, invisible particles, sometimes described as ghost particles because they can travel through solid objects very easily, like ghosts. They are all around us—trillions of neutrinos pass harmlessly through you every second!
Where do they come from?
The neutrinos we see here on Earth mostly are produced in the sun, nuclear reactors, and particle accelerators. IceCube is looking for neutrinos created far away in outer space, which are called astrophysical neutrinos. They are created by powerful astrophysical phenomena like exploding stars (called supernovae or hypernovae), black holes, and mergers between black holes and stars.
The neutrinos are ejected throughout the cosmos at close to the speed of light, and they can travel for billions and billions of miles in a totally straight line, carrying information about the sources that created them. Some astrophysical neutrinos make it to Earth...and some go through Earth and make it to the South Pole.
How does IceCube see these ghostly particles? IceCube can’t see neutrinos directly, but it can see signals that a neutrino interacted. When extremely energetic astrophysical neutrinos reach the South Pole, they occasionally collide with an atom in the ice. This creates particles that produce a small amount of blue light.
We put over 5,000 light sensors deep in the ice that activate when they observe this blue light. When the sensors activate in quick succession, it tells our scientists that an astrophysical neutrino might have passed through!
Watch an animation of this process in this 11-second video:
Colors tell scientists the relative time that the sensor was activated. The red indicates the sensors that first saw the light from the neutrino collision, and the blue/green designates sensors that detected the light later. So by following the colors from red to blue, you can get an idea of which way the neutrino traveled through the ice.
The other part of our display is the IceCube Laboratory, a school bus-sized, 2-story building at the South Pole that sits on the surface of the ice on top of the telescope. It contains computers that send data up to UW–Madison. If IceCube sees a signal that looks like it could be an astrophysical neutrino, the information can be sent up north in less than one minute!
Since most of our experiment is buried in the ice, the IceCube Laboratory is the iconic symbol of IceCube at the South Pole. Our scientists have taken many beautiful photos of it...
Want to learn more about IceCube and WIPAC?
For kids and families: Watch a recording of our kid-friendly webcast with the South Pole from earlier this year, including special guest, Jargie the Science Girl!
Explore our websites to learn more about our experiments: wipac.wisc.edu and icecube.wisc.edu.
Try some of our family activities that can be printed at home:
- IceCube coloring sheets
- Paper snowflake patterns
- Our educational comic book series, Adventures with Rosie & Gibbs (available in 9 languages)