The article is about the most energetic particle ever discovered...
WHAT IS THE OH-MY-GOD PARTICLE?
The Oh-My-God Particle was an ultra-high-energy cosmic ray with an energy of about 300 EeV, or 43 million TeV, which is roughly 40 million times more energetic than those of particles produced in the Large Hadron Collider. It is believed to have been a proton, though this is not 100% confirmed. It could also have been a heavier atomic nucleus (like an iron nucleus), but a proton is the most likely candidate based on the energy and how it interacted with the Earth's atmosphere. It was detected on 15th October, 1991, by the Fly’s Eye Experiment, in Utah, USA.
WHAT IS COSMIC SCIENCE?
Cosmic science is the study of the universe beyond Earth, focusing on the origin, structure, behaviour, and evolution of celestial bodies and cosmic phenomena. It combines elements of astrophysics, cosmology, astronomy, and particle physics. Topics include stars, galaxies, black holes, cosmic rays, and the Big Bang. It helps us understand how the universe works at both the cosmic and quantum scales.
What is the Large Hadron Collider (LHC)?
The Large Hadron Collider (LHC) is the world’s largest and most powerful particle accelerator, operated by CERN (the European Organisation for Nuclear Research), located near Geneva, Switzerland.
It accelerates protons and heavy ions close to the speed of light and smashes them together to study the fundamental building blocks of the universe.
The LHC lies in a 27-kilometre circular tunnel, buried about 100 metres underground.
It uses powerful magnets to steer and accelerate particles to extremely high energies before colliding them.
One of its most famous discoveries is the Higgs boson, confirmed in 2012, which helps explain why particles have mass.
WHAT IS A COSMIC RAY?
Cosmic rays are high-energy particles that travel through space and occasionally strike Earth's atmosphere. Most of them are protons, but they can also be atomic nuclei or electrons. First discovered in 1912 by Victor Hess during a balloon experiment, cosmic rays have since become a major focus in astrophysics. They matter because they carry clues about powerful cosmic events like supernovae, black holes, and even the early universe.
They are of 2 types:
Primary cosmic rays come directly from space and hit Earth's atmosphere.
Secondary cosmic rays are formed when primary cosmic rays collide with atmospheric particles and break into smaller pieces.
By energy level, they can be:
Low- to medium-energy rays – mostly from the Sun.
High-energy rays originate from distant space events.
Ultra-high-energy cosmic rays (UHECRs) are extremely rare and powerful, like the "Oh-My-God" particle.
High-Energy and Ultra-High-Energy Cosmic Rays (UHECRs)
Cosmic rays become truly fascinating at ultra-high energies:
High-energy rays can reach energies above 10¹⁸ electronvolts (EeV). UHECRs like the Oh-My-God particle detected in 1991 had energy ~3×10²⁰ eV, far beyond what man-made accelerators like the LHC can achieve.
Studying these rays is hard because they’re extremely rare and hard to trace back to their source.
The possible sources are:
Active Galactic Nuclei (AGN)
These are supermassive black holes at the centre of galaxies.
They emit powerful jets of particles and radiation.
Strong magnetic fields can accelerate protons to ultra-high energies.
2. Quasars
A type of AGN, extremely luminous and distant.
Supermassive black holes also power quasars.
They have the potential to function as massive accelerators of particles.
3. Gamma-Ray Bursts (GRBs)
These are the most intense explosions known to exist in the universe.
Thought to result from the collapse of massive stars or neutron star mergers.
These explosions are short-lived yet intense, making them potential sites for the generation of UHECRs.
4. Blazars
Blazars represent a unique form of AGN that directs its jet towards Earth.
Blazars are characterised by their extreme brightness and high variability.
Their extreme energy output makes them prime candidates for UHECRs.
5. Radio Galaxies
Emit strong radio waves due to relativistic jets.
Example: Centaurus A, which is a strong nearby candidate.
6. Supernova Remnants
Supernova remnants can accelerate cosmic rays, typically to lower energies.
They may contribute to the acceleration of lower-energy cosmic rays, which are not UHECRs, but they are still significant.
7. Pulsars and Magnetars
Highly magnetised neutron stars.
Could accelerate particles under extreme magnetic and rotational forces.
Comparison of High-Energy Cosmic Rays
To understand their power, compare:
These cosmic rays are millions of times more energetic than anything we can create on Earth.
Detection and Measurement of Cosmic Rays
Scientists use huge detectors to study cosmic rays:
Ground-based detectors like the Pierre Auger Observatory detect the particle showers that cosmic rays cause in Earth’s atmosphere.
Space-based detectors like the Fermi Gamma-ray Telescope and AMS on the ISS directly observe cosmic rays before they hit Earth.
Detection techniques include:
Cherenkov radiation (light created when particles move faster than light in a medium),
Scintillation (flashes of light in special materials),
Calorimetry (measuring energy deposited in detectors).
Fundamentals Behind Cosmic Rays
Understanding cosmic rays requires basic particle physics:
They involve protons, electrons, neutrinos, and atomic nuclei.
These particles interact with Earth's atmosphere using electromagnetic and nuclear forces.
Concepts like E = mc² from Einstein's relativity help explain how particles gain mass or energy at high speeds.
When cosmic rays hit the atmosphere, they create a particle shower — a cascade of particles like pions, muons, and gamma rays.
Cosmic Microwave Background (CMB) and Other Radiation
The Cosmic Microwave Background (CMB) is leftover radiation from the Big Bang, filling the universe like a faint glow. While it's not a cosmic ray, it’s closely related:
CMB tells us about the early universe just 380,000 years after the Big Bang.
Cosmic rays and CMB interact, leading to the formation of new particles – pion production – limiting how far ultra-high-energy rays can travel (due to the GZK cutoff).
GZK cutoff: The ultra-high-energy rays (UHERs) interact with low-energy particles, which may include CMB particles, leading to pion production. This process causes them to lose energy and limits their travel distance in space; once they lose a certain amount of energy, they can no longer be classified as UHERs.
Applications and Implications
Cosmic ray research has many important uses:
It aids scientists in comprehending the workings of the universe, encompassing the forces of nature and the composition of matter.
Ensures space travel safety, as astronauts are exposed to higher radiation.
Secondary particles and cloud formation have the potential to impact Earth's climate and atmospheric chemistry.
Recent Missions and Experiments
Here are some of the latest efforts in cosmic ray science:
AMS (Alpha Magnetic Spectrometer)—operating on the ISS, detects cosmic ray particles in space.
IceCube Neutrino Observatory – detects neutrinos, often linked to cosmic ray sources.
Pierre Auger Observatory – the largest cosmic ray detector on Earth.
New experiments aim to solve mysteries like: Where do UHECRs come from? Are they linked to dark matter?
The answers to this question will revolutionise and deepen our understanding of these particles.
Name- Dharmik Verma
Batch code: 0028
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