10 most difficult space riddles A list of ten (out of 52) space related questions that are the most often answered incorrectly Space quiz What is the second brightest star in the night time sky, after Sirius?Canopus is the brightest star in the southern constellation of Carina, and the second brightest star in the night time sky, after Sirius. Its name is generally considered to originate from the mythological Canopus, who was a navigator for Menelaus, king of Sparta.very hard 17% ArcturusArcturus14%CanopusCanopus17%VegaVega57%ProcyonProcyon10%Created by: Ninjai. Statistics based on 87 answers in 2 languages »stars riddles » What astronomical object emerges sometimes from supernova instead of a black hole?Magnetar. A magnetar is a type of neutron star with an extremely powerful magnetic field. The magnetic field decay powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays. As of March 2016, only 23 magnetars are known, with six more candidates awaiting confirmation.very hard 23% MagnetarMagnetar23%BlazarBlazar12%QuasarQuasar43%only a black hole can emerge from supernovaonly a black hole can emerge from supernova21%Created by: Ninjai. Statistics based on 2169 answers in 3 languages »astronomy riddles » What is the largest discovered star? (by radius)UY Scuti is a bright red supergiant and pulsating variable star in the constellation Scutum. It is currently the largest known star by radius and is also one of the most luminous of its kind. It has an estimated radius of 1,708 solar radii (1.188×109 kilometres; 7.94 astronomical units); thus a volume nearly 5 billion times that of the Sun. It is approximately 2.9 kiloparsecs (9,500 light-years) from Earth. If placed at the center of the Solar System, its photosphere would at least engulf the orbit of Jupiter.very hard 24% VY Canis MajorisVY Canis Majoris32%V396 CentauriV396 Centauri31%UY ScutiUY Scuti24%Alfa PerseiAlfa Persei11%Created by: Dev. Statistics based on 1556 answers in 3 languages »astronomy riddles » What is the name of the hypothetical last stage of the evolution of Sun-sized stars?Black dwarf. A black dwarf is a theoretical stellar remnant, specifically a white dwarf that has cooled sufficiently that it no longer emits significant heat or lightvery hard 24% White dwarfWhite dwarf22%Black dwarfBlack dwarf24%Gray dwarfGray dwarf3%Red dwarfRed dwarf50%Created by: Tschuka. Statistics based on 3321 answers in 5 languages »astronomy riddles » What does the word "planet" mean?"wandering stars" . The word is typically traced back to the ancient Greeks, who believed the Earth was stationary at the center of the universe while objects in the sky revolved around it. The Greek term asters planetai mean "wandering stars" and described the tiny lights that moved across the sky more dramatically than stars when compared over weeks and months. These wandering stars, back then, amounted to Mercury, Venus, Mars, Jupiter and Saturn.very hard 26% "round object""round object"18%"wandering stars" "wandering stars" 26%"celestial body""celestial body"35%"rocky star""rocky star"19%Created by: Tschuka. Statistics based on 288 answers in 2 languages »astronomy riddles » The idea that the nascent universe passes through the phase of exponential expansion, which was driven by the positive density of vacuum energy, is called;Cosmic inflation. Alan Guth formally proposed the idea of cosmic inflation in 1981, the idea that the nascent universe passed through a phase of exponential expansion that was driven by a positive vacuum energy density (negative vacuum pressure).very hard 27% Cosmic inflationCosmic inflation27%Grand unification theoryGrand unification theory25%Theory of SupersymmetryTheory of Supersymmetry15%All answers are correct.All answers are correct.31%Created by: Tschuka. Statistics based on 4810 answers in 2 languages »universe riddles » What was the name of the first and only Soviet space shuttle?Buran (Snowstorm or Blizzard) was the first spaceplane to be produced as part of the Soviet Buran programme. OK-1K1 completed one unmanned spaceflight in 1988, and was destroyed in 2002 It remains the only Soviet reusable spacecraft to be launched into space. very hard 28% UralUral19%BuranBuran28%GagarinGagarin21%BaikalBaikal31%Created by: Tschuka. Statistics based on 3258 answers in 2 languages »technical riddles » Which two planets are the closest in size?Uranus and Neptune. The diameters of Uranus and Neptune are respectively 25 362 km and 24 622 km - the difference is only 2.92%.very hard 28% Mercury and MarsMercury and Mars16%Venus and EarthVenus and Earth43%Jupiter and SaturnJupiter and Saturn10%Uranus and NeptuneUranus and Neptune28%Created by: Tschuka. Statistics based on 967 answers in 3 languages »planets riddles » The largest impact crater of the Solar System is:Caloris Planitia is a plain within a large impact basin on Mercury, informally named Caloris, about 1,550 km in diameter. It is one of the largest impact basins in the Solar System. The crater, discovered in 1974, is surrounded by a ring of mountains approximately 2 km (1.2 mi) tall. very hard 29% Valles MarinerisValles Marineris31%CalorisCaloris29%Rupos AltaiRupos Altai21%AristarchusAristarchus17%Created by: Tschuka. Statistics based on 1586 answers in 2 languages »Solar System riddles » When was the Hubble Space Telescope launched into orbit?In 1990. The Hubble Space Telescope (HST) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. Although not the first space telescope, Hubble is one of the largest and most versatile, and is well known as both a vital research tool and a public relations boon for astronomy. very hard 29% In 1982In 198213%In 1986In 198637%In 1990In 199029%In 1994In 199419%Created by: Tschuka. Statistics based on 2157 answers in 2 languages »astronautics riddles » Play space quiz and see all the questions.