How does Poynting-Robertson drag move tiny asteroid dust particles toward Earth?

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Meteorite The Hoba meteorite, lying where it was discovered in 1920 near Grootfontein, Namibia. The largest meteorite on Earth and an iron meteorite by classification, it consists of a nickel-iron alloy and is estimated to weigh about 60 tons.

The premise that Poynting-Robertson drag moves asteroid dust particles toward Earth is accurate. This process specifically affects interplanetary dust particles that are less than a few hundred micrometres across.1

Poynting-Robertson drag functions through the interaction between these tiny particles and solar radiation. As these particles orbit the Sun, they absorb and re-emit solar energy, which creates a subtle drag force that causes their orbits to decay. This force results in the particles spiraling inward from the asteroid belt toward the inner solar system, eventually entering Earth-crossing orbits.1

The time required for this journey depends on the particle's size and its starting position within the asteroid belt. For instance, dust particles measuring 10–50 micrometres are estimated to take approximately 100,000 years to reach Earth's vicinity. It is important to note that particles significantly smaller than one micrometre are not moved toward Earth by this process; instead, they are pushed out of the solar system entirely by radiation pressure.1