Final answer:
True, a planet requires both an atmosphere and a magnetic field for auroras to occur. Charged particles from the solar wind interact with atmospheric molecules at the poles, resulting in the light displays known as auroras.
Step-by-step explanation:
The statement that a planet must have an atmosphere and a magnetic field to have an aurora is True. Auroras occur when charged particles from the solar wind are funneled by a planet's magnetic field towards the planet's poles and interact with the atmospheric particles. The magnetic field guides the solar particles, and these particles then collide with gas molecules in the atmosphere, leading to the emission of light that is seen as the aurora. This process not only creates the aurora borealis (northern lights) but can also generate the aurora australis (southern lights) in the Earth's Southern Hemisphere. Other planets with strong magnetic fields, such as Jupiter and Saturn, have also been observed to have auroras.