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Project GRAND aims to use 200,000 antennas to detect neutrinos and extreme cosmic particles across a gigantic area.
In one of the most ambitious projects in modern astroparticle physics, the GRAND Collaboration is working to transform large terrestrial areas into a kind of planetary antenna for almost invisible particles coming from the deep Universe. According to an article presented at ICRC 2023 and published by Proceedings of Science on September 27, 2024, the Giant Radio Array for Neutrino Detection, GRAND, is a planned observatory to detect ultra-high energy neutrinos, cosmic rays, and gamma rays, with a final configuration expected to be 200,000 radio antennas distributed over 200,000 km² in sub-arrays spread across the world.
The idea seems straight out of science fiction because GRAND does not rely on traditional telescopes to observe the sky. The project’s strategy is to capture the radio emission generated by particle showers in the atmosphere, produced when extreme energy particles interact with the air or the Earth’s crust. The planned design divides the system into about 20 sub-arrays of approximately 10,000 km² each, creating an observation structure much larger than any conventional laboratory detector.
Project GRAND aims to create the largest neutrino detector ever planned
The name GRAND stands for Giant Radio Array for Neutrino Detection. The project was conceived by an international collaboration of researchers seeking to detect extremely rare particles using a completely different approach from traditional observatories.
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Instead of relying on large underground tanks or submerged ocean detectors, GRAND intends to use thousands of antennas distributed in remote mountainous regions.
The scale of the project is difficult to visualize. The complete plans call for up to 200,000 antennas spread over approximately 200,000 km², an area similar to the size of entire countries or large Brazilian states.
This dimension is necessary because ultra-high energy neutrinos almost never interact with matter. Detecting them requires observing gigantic areas for long periods.
Neutrinos are ghost particles that traverse entire planets almost without collision
Neutrinos are often called “ghost particles.” They have an extremely small mass and interact very little with matter. Trillions of them pass through the human body every second without leaving any perceptible effect.
This makes their detection extremely difficult. Most of the time, they pass through entire planets practically without colliding with anything. GRAND intends to use mountains as a strategic element of the system.
The idea is that ultra-energetic neutrinos will traverse the Earth and eventually interact near mountain slopes, generating secondary particles.
These particles would produce atmospheric showers capable of emitting radio signals detectable by antennas scattered across the terrain.
Earth’s atmosphere becomes a giant screen to record cosmic collisions
When extreme energy particles enter the atmosphere, they trigger cascades of secondary particles.
These cascades emit very fast and weak radio signals. The role of the antennas is to capture these signals and allow scientists to reconstruct the trajectory and energy of the original event.
In practice, the project transforms the atmosphere itself into a gigantic cosmic observation surface.
One of the reasons for scientific interest is the absurd energy involved. Some neutrinos and cosmic rays carry energies millions of times higher than those produced in accelerators like CERN.
These events can reveal extreme phenomena linked to supermassive black holes, violent cosmic explosions, and still poorly understood objects.
Scientists want to discover the origin of the Universe’s most extreme cosmic rays
One of the big questions in modern astrophysics concerns precisely the origin of ultra-high energy cosmic rays.
Scientists know they reach Earth, but they still don’t fully understand which objects can accelerate them to such absurd energies. Black holes, active galactic nuclei, and stellar explosions are among the main candidates.
To function correctly, GRAND needs to operate in electromagnetically extremely quiet areas.
Interferences produced by cities, telecommunications antennas, and electronic equipment can disrupt the sought-after signals. Therefore, isolated mountainous regions appear as ideal candidates to host some of the antennas.
System will be modular and built in smaller stages
The complete project is still under development and is expected to advance in phases. Before the massive installation of 200,000 antennas, researchers are working on smaller prototypes to validate technology, algorithms, and detection methods.
These steps help verify if the approach can indeed efficiently identify ultra-high-energy neutrinos. GRAND is part of a growing trend in modern astronomy: using radio waves to investigate extreme phenomena.
Giant radio telescopes already study black holes, distant galaxies, and mysterious cosmic signals. The difference here is using radio to detect nearly invisible particles. This enormously expands the possibilities for observing the deep Universe.
Detecting neutrinos can reveal invisible regions of the cosmos
Neutrinos can pass through regions that block light, X-rays, and other forms of radiation. This means they carry information about extreme cosmic environments normally inaccessible to conventional telescopes.
Capturing them can help scientists see hidden parts of the Universe. GRAND brings together extremely complex scientific areas.
The initiative combines particle physics, radio astronomy, computing, signal analysis, and large-scale engineering. Furthermore, the expected data volume requires advanced artificial intelligence and distributed processing systems.
Observatory can help understand the most violent events ever recorded in the cosmos
Scientists expect the system to help track phenomena linked to:
- gamma-ray bursts
- extreme cosmic collisions
- active black holes
- relativistic jets
- unknown energetic events
These phenomena are among the most violent ever observed in the Universe. The most impressive aspect of the project is perhaps its scale.
Instead of a single telescope, GRAND functions as a distributed infrastructure on a continental scale. It is an example of how modern science has begun to build gigantic systems to answer fundamental questions about the origin, structure, and behavior of the Universe.
The 200,000 antennas can turn mountains into a machine for observing invisible particles
If the project reaches its full configuration, mountains scattered across the planet could function as part of a gigantic cosmic detector.
The proposal seems futuristic because it transforms natural elements of Earth into active components of a global scientific machine. The ultimate goal is to capture particles so rare and energetic that they can carry clues about the most extreme events ever produced in the cosmos.
Did you imagine that entire mountains could become part of a planetary detector created to capture nearly invisible particles coming from the most violent regions of the Universe?
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