10 most difficult astronomy riddles A list of ten (out of 55) astronomy related questions that are the most often answered incorrectly Astronomy quiz What is the most common element (by mass) forming the planet Earth?Iron is most abundant in the Earth's outer and inner core, and it is the fourth most common element in the Earth's crust.very hard 29% carboncarbon29%oxygenoxygen21%ironiron29%siliconsilicon20%Created by: globalquiz.org. Statistics based on 8534 answers in 2 languages »Earth riddles » Which rover was the first to explore Mars?Sojourner was the first Mars rover. It was much smaller then Curiosity, whose wheel is about the size of the whole Sojourner. It landed on July 4, 1997 as part of Mars Pathfinder mission on Mars's Ares Vallis and remainded in contact with Earth till September 27, 1997.very hard 29% CuriosityCuriosity32%OpportunityOpportunity19%SojournerSojourner29%SpiritSpirit18%Created by: smyru. Statistics based on 3703 answers in 2 languages »space riddles » Which of the following cosmic structures is the largest?Galaxy filaments are the largest known structures in the universe. They group galaxy superclusters, which in turn are formed by cluster composed of galaxies. Hercules–Corona Borealis Great Wall is considered the largest known structure of Universe. It is estimated to span 10 billions light years. very hard 30% GalaxyGalaxy26%Galaxy filamentGalaxy filament30%Galaxy clusterGalaxy cluster2%SuperclusterSupercluster39%Created by: smyru. Statistics based on 3520 answers in 2 languages »universe riddles » What is the source of the most powerful release of energy in the universe, second in scale only to the Big Bang?Gamma-ray bursts are the brightest in the universe, even brighter than the glare of quasars, second only to the brightness and power of the Big Bang. It is believed that arise during disruption of stars by black holes.very hard 32% supermassive starssupermassive stars4%quasarsquasars19%gamma-ray burstgamma-ray burst32%supernovasupernova43%Created by: Krzysztof Moskal. Statistics based on 3613 answers in 2 languages »stars riddles » This is an iron buoy. Where were its atoms formed?In a high-mass star preceding Sun. Radioactive nickel-56 (which decays to the most common isotope of iron) is the last element to be produced before the collapse of a supernova. That is why the iron was abundantly scattered into space after the supernova explosion.very hard 34% in a high-mass star preceding Sunin a high-mass star preceding Sun34%in the Sunin the Sun8%in the Earth's corein the Earth's core29%in the Earth's crustin the Earth's crust28%Created by: life-o-holic. Statistics based on 13624 answers in 2 languages »elements riddles » What was the exposure time of this photo?About 1 hour. The length of stars trails is pretty much the same as the distance travelled by an hour hand of clock during 30 minutes. But the Earth rotates twice as slow compared to the hour hand of a clock (one rotation per day, while clock's hour hand makes two).very hard 35% about 10 secondsabout 10 seconds16%about 10 minutesabout 10 minutes12%about 1 hourabout 1 hour35%about 8 hoursabout 8 hours35%Created by: globalquiz.org. Statistics based on 7450 answers in 2 languages »time riddles » Who first proposed the principle of the heliocentric theory?Aristarchus of Samos, Aristarchos (approx. 320 approx. 250 BC), was the Greek astronomer and mathematician from Alexandria. He believed that the Earth revolves around the Sun, which is the center of the world, and the occurrence of day and night is related to the Earth's rotation around its axis. He also tried to mathematically determine the size of the Sun and the Moon, as well as their distance from Earth. very hard 35% GalileoGalileo27%Nicolaus CopernicusNicolaus Copernicus25%ArchimedesArchimedes11%Aristarchus of SamosAristarchus of Samos35%Created by: Krzysztof Moskal. Statistics based on 6282 answers in 2 languages »ancient history riddles » Which famous astronomer was also a succesful sportsman?Edwin Hubble. In his younger days he was noted more for his athletic prowess than his intellectual abilities. He won seven first places in a single high school track and field meet in 1906. He also set the state high school record for the high jump in Illinois, and practiced amateur boxing.very hard 36% Galileo GalileiGalileo Galilei21%William HerschelWilliam Herschel14%Edmond HalleyEdmond Halley28%Edwin HubbleEdwin Hubble36%Created by: globalquiz.org. Statistics based on 8894 answers in 2 languages »scientists riddles » This plaque, carried by Pioneer 10 and Pioneer 11 space probes, describes the location of the Sun. What are the points at the ends of the lines?Pulsars. Each of the line includes binary encoding of pulsar frequency, so these can be easily recognized. The hydrogen spin-flip transition frequency is used as the unit of time (Hydrogen particle at the top of the image).very hard 37% planets of the Solar Systemplanets of the Solar System31%galaxiesgalaxies15%quasarsquasars14%pulsarspulsars37%Created by: Sophie Letherman. Statistics based on 7955 answers in 4 languages »astronautics riddles » What is the name of first in history cosmic tourist (astrotourist)?Dennis Tito. Dennis Anthony Tito is an American engineer and multimillionaire, most widely known as the first space tourist to fund his own trip into space. Tito paid a reported $20 million to the Russian Federal Space Agency.very hard 37% Neil Alden ArmstrongNeil Alden Armstrong30%Guy LalibertéGuy Laliberté13%Dennis TitoDennis Tito37%Richard GarriottRichard Garriott19%Created by: Paweł Kołodziejczyk. Statistics based on 7957 answers in 2 languages »tourism riddles » Play astronomy quiz and see all the questions.