Explore atomic nuclei, radioactive decay, nuclear fusion, fission reactors, and the physics powering stars.
Everything in the universe is made of atoms. At the center of every atom lies the nucleus, containing protons and neutrons.
Proposed by Albert Einstein, this equation shows that mass can be converted into energy. Nuclear reactions release enormous energy because tiny amounts of mass are transformed directly into energy.
The nucleus is held together by the strong nuclear force, one of the four fundamental forces in physics.
Some atomic nuclei are unstable and spontaneously decay into more stable forms while releasing radiation.
This equation describes how radioactive materials decay over time.
| Type | Description |
|---|---|
| Alpha | Helium nuclei, heavy and weakly penetrating |
| Beta | Fast electrons or positrons |
| Gamma | High-energy electromagnetic radiation |
Half-life is the time required for half of a radioactive substance to decay.
Nuclear fission occurs when a heavy nucleus splits into smaller nuclei, releasing massive amounts of energy.
When Uranium-235 absorbs a neutron, it becomes unstable and splits apart.
Modern reactors use controlled fission reactions to heat water and generate electricity.
Fusion occurs when light nuclei combine into a heavier nucleus. This process powers stars, including the Sun.
Hydrogen isotopes fuse together under enormous temperature and pressure conditions.
Fusion requires temperatures above 100 million degrees Celsius. Scientists use magnetic confinement systems such as tokamaks to contain the plasma.
Magnetic fields control charged plasma particles inside fusion reactors.
Experimental reactors such as ITER aim to achieve sustainable net-positive fusion energy for the first time in history.