The most difficult sky riddles A list of sky related questions that are most often answered incorrectly Nature quiz What does the Bortle scale refer to?Brightness of the night sky. The Bortle scale is a nine-level numeric scale that measures the night sky's brightness of a particular location. It quantifies the astronomical observability of celestial objects and the interference caused by light pollution. It was created by John E. Bortle in 2001.very hard 34% spectrum of the starsspectrum of the stars20%types of nebulaetypes of nebulae27%brightness of the night skybrightness of the night sky34%size of the planetssize of the planets16%Created by: Ninjai. Statistics based on 2280 answers in 3 languages »space riddles » What is larger on the sky: the Moon or the Sun? (by apparent size)Sometimes the Moon, sometimes the Sun. The Moon's orbit is elliptical, and its apparent diameter varies by 10%. This is why both total eclipses (if the Moon is larger) and annular eclipses (if the Sun is larger) happen.hard 43% the Sunthe Sun18%the Moonthe Moon23%both are identicalboth are identical14%sometimes the Moon, sometimes the Sunsometimes the Moon, sometimes the Sun43%Created by: pan Krzyżówka. Statistics based on 11844 answers in 3 languages »Sun riddles » What cloud is it?Cumulus clouds are clouds which have flat bases and are often described as "puffy", "cotton-like" or "fluffy" in appearance. Cumulus clouds can be formed from water vapor, supercooled water droplets, or ice crystals, depending upon the ambient temperature. They come in many distinct subforms, and generally cool the earth by reflecting the incoming solar radiation. hard 44% cumulonimbuscumulonimbus13%cirruscirrus29%cumuluscumulus44%stratusstratus12%Created by: Tschuka. Statistics based on 5306 answers in 2 languages »clouds riddles » What cloud is it?Cumulonimbus, from the Latin cumulus ("storm cloud"), is a dense, towering vertical cloud associated with thunderstorms and atmospheric instability, forming from water vapor carried by powerful upward air currents. If observed during a storm, these clouds may be referred to as thunderheads. Cumulonimbus can form alone, in clusters, or along cold front squall lines. These clouds are capable of producing lightning and other dangerous severe weather, such as tornadoes. hard 46% stratusstratus7%cumuluscumulus36%cumulonimbuscumulonimbus46%cirrostratuscirrostratus9%Created by: Tschuka. Statistics based on 5856 answers in 2 languages »weather riddles » This is a rare phenomenon called iridescent clouds. It occurs in the clouds with ...Small droplets or ice crystals. The effect is similar to irisation. Iridescent clouds are a diffraction phenomenon caused by small water droplets or small ice crystals individually scattering light. Larger ice crystals do not produce iridescence, but can cause halos, a different phenomenon.average 60% volcanic dustsvolcanic dusts13%sulphuric acidsulphuric acid15%detergent vaporsdetergent vapors10%small droplets or ice crystalssmall droplets or ice crystals60%Created by: Tschuka. Statistics based on 19732 answers in 2 languages »atmosphere riddles » Which direction was the camera pointing at while taking this picture?North. The entire celestial sphere seems to rotate slowly around the North-South axis of Earth's rotation. So the camera must have been pointed North or South, depending on the hemisphere the photo was taken at. But the bright star in the center must be Polaris, as the south celestial pole currently lacks a bright star to mark its position. average 64% NorthNorth64%SouthSouth13%EastEast11%WestWest10%Created by: globalquiz.org. Statistics based on 17118 answers in 2 languages »photography riddles » Play nature quiz and see all the questions.