Similarity of atomic world and solar system

Atom (Bohr model):

- Dense central nucleus (protons + neutrons).

- Electrons orbit around it in shells.

Solar System:

- Massive central Sun.

- Planets orbit around it in paths.

Atom: Held together by electromagnetic force (negative electrons attracted to positive nucleus).

Solar System: Held together by gravity (planets attracted to the Sun’s mass).

Both forces follow an inverse-square law (strength decreases with the square of distance).

However, electrons don’t move in neat circular orbits like planets. Instead, quantum mechanics tells us they exist in probability clouds, not fixed paths. If atoms really behaved like tiny solar systems, they would collapse quickly due to radiation loss. Quantum rules prevent that.

In classical electrodynamics, an electron orbiting a nucleus is an accelerating charge. Accelerating charges must emit electromagnetic radiation, losing energy continuously. That would make the electron spiral into the nucleus in about 10⁻¹¹ seconds --- atoms would collapse, and matter as we know it couldn’t exist.

Acceleration isn’t just about speeding up or slowing down. In physics, acceleration means any change in velocity, and velocity includes both speed and direction. So, even if an electron were moving at a constant speed around the nucleus, it would still be constantly changing direction. That change in direction means it has a centripetal acceleration toward the nucleus.

Quantum mechanics says electrons can only occupy discrete energy states. They cannot radiate energy continuously; they can only “jump” between levels, emitting or absorbing photons of specific energies. In the lowest state (the ground state), there’s no lower level to fall into, so no radiation is emitted.

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