Quiz Topic Sheet

Light and Shadow in the Sky

Many phenomena offer a unique and spectacular experience for skywatchers, from simple observation with the naked eye to the use of advanced telescopes for the finest details.


Astronomical phenomena

  • Stars and constellations: Fixed points of light forming recognizable patterns.
  • Planets: Visible like stars but with a glow that doesn't flicker, often brighter.
  • Milky Way: Band of light crossing the sky, made up of billions of distant stars.
  • Galaxies and nebulae: Visible to the naked eye under very good conditions or with a telescope, appearing as small luminous clouds.
  • Meteors and meteor showers (shooting stars): Streaks of light created by debris entering the Earth's atmosphere.
  • Comets : Visible with the naked eye or binoculars, characterized by their shiny hair and sometimes a tail.

Atmospheric phenomena

  • Aurora (Boreal and Austral): Colored lights dancing in the sky, caused by the interaction between solar particles and the Earth's magnetic field.
  • Rainbows: Spectra of light formed by the refraction, reflection and dispersion of light through water droplets.
  • Halos, arcs and pillars of light: Luminous circles or pillars of light appearing around the Sun or Moon, caused by the refraction of light through ice crystals in the atmosphere.
  • Lightning: sudden, bright electrical discharges during thunderstorms.

Phenomena related to artificial objects

  • Satellites: Points of light moving regularly across the sky, including the International Space Station (ISS), which is particularly visible.
  • City lights and light pollution: Although technically not a natural phenomenon, light emanating from urban areas can illuminate the night sky, reducing the visibility of stars.

Occasional events

  • Solar and lunar eclipses: Rare occasions when the Moon passes between the Earth and the Sun, or when the Earth passes between the Sun and the Moon, casting a shadow that partially or totally blocks the sunlight.
  • Transits and occultations: Moments when one celestial object passes in front of another, such as a transit of Venus in front of the Sun or an occultation of a star by the Moon.

Further Information


Quiz questions preview

  • What optical phenomenon discovered by Lord Rayleigh in the 19th century explains the blue color of the sky?

    Rayleigh diffraction | Rayleigh scattering | Rayleigh interference | Rayleigh polarization
  • A phenomenon produced by the reflection of sunlight on the dust particles between the planets.

    Interplanetary halo | Interstellar glow | Cosmic mist | Zodiacal light
  • How many colors are there in the rainbow?

    12 | 7 | 5 | 10
  • In which galaxy are all the stars visible to the naked eye located?

    The Andromeda Galaxy | The Hercules Cluster | The Large Magellanic Cloud | The Milky Way
  • What is the common name for meteors that enter the Earth's atmosphere and glow as they burn?

    Shooting stars | Rainbows | Cosmic flashes | Northern lights