How to put 170 atoms in an atom
Fitting 170 Atoms Inside a Single Atom
It is a well-known fact in physics that atoms are composed primarily of empty space. While the concept of "size" becomes surreal at the subatomic level, the disparity between the center and the edge of an atom is staggering.
The Scale of the Void
To visualize this, consider the ratio between the nucleus and the electron's orbital:
| Atomic Component | Relative Scale | Real-World Analogy |
|---|---|---|
| Nucleus | Extremely Small | A single grain of sand |
| Electron Orbital | Relatively Massive | A full-sized football field |
Because of this vast internal vacancy, it is theoretically possible to nest multiple atoms of the same element inside another—potentially over a hundred of them. This isn't science fiction; researchers have actually achieved this without breaking any laws of physics. The secret recipe requires one colossal atom and a group of extremely chilled ones.
Expanding the Atom: Electron Excitation
An atom is essentially a nucleus hugged by a cloud of electrons. To increase the size of the atom, you must push the outermost electron further away from the center. This process is known as electron excitation.
How it works:
- An electron absorbs external energy.
- It "jumps" to a higher, more distant orbital.
- The orbital becomes more loosely bound, increasing the atom's total radius.
This is a natural occurrence, as atoms constantly exchange energy with their environment. However, there is a limit: if the electron absorbs too much energy, it will escape the nucleus entirely. At that point, you no longer have an atom, but an ion.
The Rydberg Atom
When scientists maximize this expansion without losing the electron, they create what is known as a Rydberg atom.
Historical Note: These are named after Johannes Rydberg, a Swedish physicist who, in 1888, identified patterns in atomic spectra that eventually paved the way for our understanding of electron energy levels.
(Note: Image represents the concept of Rydberg's work)
(Actual image from source: https://i0.wp.com/signoregalilei.com/wp-content/uploads/2026/08/Rydberg_Janne_foto_Per_Bagge_AFs_Arkiv.jpg?resize=210%2C300&ssl=1)
In a lab setting, a Rydberg atom can be 1,000 times wider than a standard atom, creating a massive "room" to house other atoms.
The Cooling Challenge: Bose-Einstein Condensates
You cannot simply shove normal room-temperature atoms into a Rydberg atom. If the guest atoms have too much kinetic energy, they will collide with and knock away the fragile outer electron. To prevent this, scientists use a state of matter called a Bose-Einstein Condensate (BEC).
Temperature is essentially a measurement of how much particles are vibrating or bouncing. By cooling atoms to a temperature nearly reaching absolute zero—specifically —the atoms slow down and begin to share the same quantum state.
The 2018 Experiment: Creating the Polaron
In 2018, an international research team put these theories into practice using strontium atoms. Their process followed these steps:
- Create a BEC consisting of strontium atoms.
- Target a single atom with a precisely tuned laser.
- Excite that atom's outermost electron to transform it into a Rydberg atom.
- Trap neighboring BEC atoms within the expanded orbital.
The result was a "Rydberg polaron"—a strange, hybrid structure that behaves like a bizarre molecule.
The Capacity
Based on computer simulations, the researchers found that the internal volume of a Rydberg polaron is surprisingly spacious:
# Theoretical Capacity Simulation
atom_type = "Strontium"
host_atom = 1
guest_atoms_max = 170
total_atoms_in_one_orbital = host_atom + guest_atoms_max
print(f"Total atoms: {total_atoms_in_one_orbital}")
# Output: Total atoms: 171
While it is currently unknown if Rydberg polarons will have practical applications in daily life, they provide invaluable insights into the mechanics of quantum physics and atomic interaction.
