What is Dark Matter?
There’s more to the universe than stars, planets, asteroids, comets, and space dust. In fact, there’s a lot more to the universe that we can’t yet explain.
Scientists believe that dark matter, which we have so far only detected through its gravity-based effects in space, makes up about a quarter (26.8 percent) of the total mass and energy of the universe, and something that is driving the universe’s accelerating expansion—which scientists call dark energy—accounts for another 68.3 percent. The ordinary matter, like stars and planets and galaxies, makes up just 4.9 percent of the total mass and energy of the universe.
So there’s a BIG part of the universe that we don’t know much about. We’re not sure if dark matter is made up of undiscovered particles, or if it can be explained by tweaking the known laws of physics. Its makeup could teach us much about the history and structure of our universe.
Plan an Event
Want to plan a Dark Matter Day event in your community? We can help! Check out the links below to resources that can help you find and connect with local dark matter experts, plan a program for a particular audience, and promote and share your event with the world.
Begin preparing for Dark Matter Day 2021 by familiarizing yourself with these resources.
Celebrate Dark Matter Day
On and around October 31st, 2021 , the world will celebrate the historic hunt for the unseen—something that scientists refer to as dark matter.
Since 2017, more than 159 global, regional, and local events have been held on and around October 31 by institutions and individuals looking to engage the public in discussions about what we already know about dark matter and the many experiments seeking to solve its mysteries.
What are we learning?
From space-based telescopes to underwater detectors, scientists are leaving no stone unturned in their search for hints of dark matter.
Telescope Array System (VERITAS)
The MAGIC telescopes are currently run by an international collaboration of about 165 astrophysicists from 24 institutions and consortia from 12 countries.
Encompassing a cubic kilometer of ice, IceCube searches for nearly massless subatomic particles called neutrinos. These high-energy astronomical messengers provide information to probe the most violent astrophysical sources: events like exploding stars, gamma-ray bursts, and cataclysmic phenomena involving black holes and neutron stars."
The experiment employs the latest in high speed electronics and data acquisiton, and explores new experimental territory, only millimeters away from the incident electron beam.
ADMX is an axion haloscope, which uses a strong magnetic field to convert dark matter axions to detectable to microwave photons. The ADMX G2 experiment is one of the US Department of Energy's flagship dark matter searches, and the only one looking for axions. The experiment consists of a large magnet, a microwave cavity, and ultra-sensitive low-noise quantum electronics.
The first phase is DarkSide-50 (DS-50 Time Projection Chamber), with 50 kilograms active mass, which has been operating beneath 1,400 meters of rock in the underground INFN Gran Sasso Laboratories, located in Abruzzo, Italy, since autumn 2013. DS-50’s background suppression strategy uses 30 tons of liquid scintillator for neutron detection, and 1,000 tons of water to detect muons, both of which can mimic the signal of a dark matter particle.
One of the advantages of the PICO detector is the dramatically reduced sensitivity to background events which can cause false signals in the detector. This reduction is only applicable for larger masses of dark matter particles, and diminishes for lighter dark matter particles. The Scintillating Bubble Chamber (SBC) strives to extend this background rejection through the use of a different target material. This increases the complexity of the detector, requiring it to be kept very cold (-186°C) but the use of argon makes the possibility of detecting lighter particles possible. The light generated by the background events will be detected by new silicon photomultipliers which will allow for even greater particle discrimination.