The universe is a vast and mysterious place full of wonders. Throughout history, humans have gazed up at the cosmos and pondered the great unknowns about space and time. Riddles about the universe allow us to tap into our curiosity about existence itself. Here are 99 thought-provoking riddles about the universe along with their fascinating answers.
1-10
1. What surrounds the earth but we can’t see it?
Answer: Atmosphere
2. I’m very old but I look brand new, once you’ve seen me you might well pass through. What am I?
Answer: A black hole
3. I’m a chain of many links, wound all around in rings. Closely joined, though far apart – binding land and sea and heart. What am I?
Answer: The Solar System
4. The more you have of me, the less you can see. Look straight at me and I disappear. What am I?
Answer: Darkness
5. I’m a sphere but not a ball, I’m pregnant with fire but I never fall. I fly but I have no wings, I can scream but I have no mouth. What am I?
Answer: A comet
6. I’m often bright and beautiful, a natural work of art. But stand too close and you’ll soon depart this earthly chart. What am I?
Answer: The Sun
7. I’m not really a gemstone, but some people call me a jewel. I shine in your nights, though I’m never quite full. What am I?
Answer: The Moon
8. We come in different shapes, sizes and colors, scattered across the black blanket above. We live far, you watch from afar. What are we?
Answer: Stars
9. I’m a longtime traveler, wandering the universe alone. Cold and barren yet beautiful to some, no atmosphere to call my own. What am I?
Answer: An asteroid
10. I’m neither liquid, solid nor gas, but made of matter not easily clasped. With neutrons, electrons and protons I’m massed. What am I?
Answer: Plasma
11-20
11. I’m not a planet, but I orbit the sun. I’m made of chunks of rock and ice spun into one. What am I?
Answer: A dwarf planet
12. I’m a celestial body in outer space, with craters and plains all over my face. What am I?
Answer: A moon
13. Twinkle, twinkle way up high, in the dark and starry sky. Although I’m named for the morning, at night is when I’m most easy to spot from earth. What am I?
Answer: Venus (the morning star)
14. I’m the closest neighbor to our planet Earth, a rocky terrain is the planet of my birth. Who am I?
Answer: Mars
15. My orbit’s outside the asteroid belt, made up mostly of gas I’m quite an ice giant. What planet am I?
Answer: Uranus
16. I’m farthest from the sun, on the edge of the solar system orbiting alone. Neptune is the planet I call home.
Answer: Neptune
17. I’m the king of planets in the solar system, a gas giant is what I’m commonly called. What planet am I?
Answer: Jupiter
18. A tilted spin makes my seasons extreme, with auroras and storms I’m a planet that’s mean. What am I?
Answer: Uranus
19. My orbit’s in the asteroid belt, I’m red and rocky – can you guess? The Romans knew me as the god of war. What planet am I?
Answer: Mars
20. A hot, bright dwarf am I, the closest star to planet Earth’s sky. Gravity binds me to three others, in the constellation of the Centaur’s bow. What am I?
Answer: Proxima Centauri
21-30
21. I’m not really a star but I burn like one, debris swirling as I plummet towards the sun. What am I?
Answer: A meteor
22. Twinkling brightly in your night sky, I’m a massive ball of gases, mostly hydrogen and helium inside. What am I?
Answer: A star
23. I’m little pieces of rocks or dust, burning brightly as I enter earth’s atmosphere. What am I?
Answer: A meteoroid
24. I’m debris left after a meteor strikes land, broken pieces of a visitor from outer space. What am I?
Answer: Meteorite
25. A belt of asteroids is where I’m found, orbiting between Mars and Jupiter I abound. What am I?
Answer: The asteroid belt
26. I’m a giant illuminated cloud in space, a stellar nursery for stars taking shape. Interstellar gas and dust I do embrace. What nebula am I?
Answer: An emission nebula
27. When a star dies I can form, with glowing gases the stellar winds have blown. Remnants of a supernova I may spawn. What nebula am I?
Answer: A planetary nebula
28. When a star explodes outward I am hurled, a shock wave of particles across the universe swirled. What nebula am I?
Answer: A supernova remnant nebula
29. I’m a group of stars that form a pattern, named after a mythological creature in the night sky. What am I?
Answer: A constellation
30. I’m a huge collection of stars, gas, and dust held together by gravity. Galaxies are the building blocks of the universe in which I exist. What am I?
Answer: A galaxy cluster
31-40
31. I’m the galaxy that includes the Earth and the solar system where we reside. The Milky Way is my name upon the scrolls of cosmic time.
Answer: The Milky Way
32. I’m the expanding space that contains all matter created by the Big Bang. Dark energy and dark matter in me abound. What am I?
Answer: The universe
33. I’m the fabric of space-time itself, expanding since the original cosmic burst. Matter, energy, all existence needs me as its frame at the very first. What am I?
Answer: Space
34. When matter is pulled inward by gravity toward an infinitely dense core, I’m created in space from a large dying star. What am I?
Answer: A black hole
35. I’m the scientific theory for the origin of the universe from a great cosmic explosion. The Big Bang is the commonly known name I go by.
Answer: The Big Bang theory
36. I’m the name for the continuous expansion of space that began with the Big Bang. Distances between galaxies grow greater the farther apart they are.
Answer: Hubble’s law
37. I’m the dense, central region of a galaxy where a supermassive black hole resides. I’m active when consuming material, emitting radiation across the electromagnetic spectrum.
Answer: A galactic nucleus
38. When a high-mass star collapses and explodes violently at the end of its life, I’m the resulting phenomenon. A supernova is what astronomers call me.
Answer: A supernova
39. I’m the brilliant glow from clouds of interstellar gas ionized by light from hot stars. Often seen in galaxies, nebulae and star clusters I’m espied.
Answer: Diffuse nebula
40. I’m the great unknown, the unseen matter and energy in space that make up over 95% of the total mass-energy content. Dark matter and dark energy are aspects scientists have yet to properly identify.
Answer: Dark universe
41-50
41. I’m the band of stars, gas and dust that spans the night sky, over 100,000 light years across. From within, you’d see a river of stars – that’s me!
Answer: The Milky Way galaxy
42. I’m the technical name for the day the earth and planets formed around 4.5 billion years ago. The solar system’s age is dated from me.
Answer: The solar system’s accretion
43. At the Milky Way’s center, I’m the supermassive black hole around which the galaxy orbits. Sagittarius A* is the name astronomers use to refer to me.
Answer: Sagittarius A* black hole
44. I’m the glowing, gaseous tail of a comet, always pointing away from the sun. As a comet approaches the sun, I become visible.
Answer: A comet’s tail
45. I’m the celestial firework show that occurs when particles from the sun collide with gases in earth’s atmosphere. In the north and south my lights can be seen.
Answer: The Aurora Borealis/Northern Lights
46. I’m a giant wall of hydrogen gas and plasma in the outer solar system. Stretching billions of miles, my discovery helped support the solar nebula theory.
Answer: The heliopause
47. I’m the boundary where a planet’s magnetic field doesn’t protect the atmosphere from solar winds. Past me, gases and charged particles escape into space.
Answer: The magnetosphere
48. I’m the technical term for a galaxy moving away from the Milky Way. The farther I am, the faster I recede according to Hubble’s law of cosmic expansion.
Answer: A receding galaxy
49. I’m the band of stars that the earth and other planets in the solar system orbit around. The Milky Way’s disk contains me.
Answer: The galactic plane
50. I’m the hypothetical energy that counteracts gravity and causes the universe’s expansion to accelerate. Understanding me is one of cosmology’s greatest challenges.
Answer: Dark energy
51-60
51. I’m the technical name for the solar system’s birth 4.6 billion years ago, when a giant molecular cloud collapsed and formed the sun and solar nebula.
Answer: Nebular hypothesis
52. I’m the blanket of primordial radiation left from the Big Bang, still detectable today as microwaves from all parts of the sky.
Answer: Cosmic microwave background
53. I’m the tendency of planetary orbits to align on the same geometric plane based on a star’s rotation. This supports formation from a flattened disk.
Answer: Orbital coplanarity
54. I’m the radiant light emitted by hydrogen gas from stars and galaxies. Studying me provides information about their motion.
Answer: Hydrogen spectral line
55. I’m the technical term for a galaxy moving towards the Milky Way. Like a redshift, my speed increases with distance based on Hubble’s law.
Answer: Blueshift
56. I’m the still mysterious force that causes the universe’s expansion to accelerate. Understanding me is key to learning the cosmos’s ultimate fate.
Answer: Dark energy
57. I’m the hypothetical type of matter that exists everywhere but doesn’t emit light. I’m considered the main component of dark matter in the universe.
Answer: Weakly interacting massive particles (WIMPs)
58. When atoms in space absorb light at specific wavelengths, I’m produced to indicate an element’s presence. Each element has a unique set.
Answer: An absorption spectrum
59. I’m the technical term for dwarf galaxies being pulled towards and merging with the Milky Way over billions of years.
Answer: Galactic cannibalism
60. I’m the great attractor, a gravitational anomaly pulling the Milky Way and millions of other galaxies towards me at incredible speeds.
Answer: The Laniakea supercluster
61-70
61. I’m the giant star cluster near the Milky Way’s center where many old, red stars reside. In Latin my name means “the harp”.
Answer: Messier 54
62. I’m the chaotic region where stars form inside of dense molecular clouds of gas and dust.
Answer: Stellar nurseries
63. When a white dwarf explodes from too much hydrogen accretion, I’m the resulting cosmic blast. One theory for the origin of the universe is me.
Answer: Type 1A supernova
64. I’m the technical term for the energy density of space, considered a property of the vacuum. Virtual particles spontaneously appear and disappear within me.
Answer: Quantum vacuum energy
65. I’m the invisible halo of dark matter surrounding and enveloping galaxies, and affecting their rotation rate.
Answer: Dark matter halo
66. When the universe began I was incredibly hot, energetic and dense. As the cosmos rapidly expanded I gradually cooled.
Answer: Cosmic quark-gluon plasma
67. I’m the inexplicable baryon asymmetry that resulted in matter dominating over antimatter in the observable universe.
Answer: Matter/antimatter imbalance
68. When massive, rapidly spinning stars collapse, I’m the incredibly dense, energetic result. Magnetic fields and radiation jets characterize me.
Answer: Quasar
69. I’m the hypothetical particle even smaller than quarks that some theories say vibrate in strings to create all cosmic matter and energy.
Answer: Superstring
70. I’m the brilliant flash of light predicted to occur when photons travel faster than light speed in a vacuum. Finding me would overturn Einstein’s theories.
Answer: Vacuum Cherenkov radiation
71-80
71. I’m the ooey, gooey state of matter that possibly existed nanoseconds after the Big Bang, too hot for protons and neutrons to form.
Answer: Quark-gluon plasma
72. When the largest stars expire in cataclysmic explosions, I’m the incredibly dense nugget left behind. Even light cannot escape my grasp.
Answer: Stellar black hole
73. I’m the giant halo of plasma gases encompassing the sun, where electromagnetic storms frequently erupt.
Answer: The heliosphere
74. Albert Einstein described me as a curvature or warp in the fabric of space-time caused by mass. Gravity is my effect.
Answer: Spacetime
75. I’m the hypothetical particle that mediates the force of gravity in most modern theories. Finding me would be revolutionary.
Answer: Graviton
76. When Einstein’s theory of special relativity breaks down at immense densities, I take over as the governing physics.
Answer: Quantum gravity
77. I’m the technical term for when massive stars burn through their nuclear fuel and gravity causes a catastrophic collapse.
Answer: Stellar collapse
78. When the largest dying stars violently explode, I’m the powerful burst of gamma radiation emitted. One day I may bathe Earth.
Answer: Gamma ray burst
79. I’m the brilliant flash created when two neutron stars collide and combine. Telescopes observe my glowing remnants.
Answer: Kilonova
80. I’m the stream of charged particles that solar flares and coronal mass ejections propel out through the solar system.
Answer: Solar wind
81-90
81. When cometary debris burns up in Earth’s atmosphere, I’m the visible streak briefly etched across the night sky.
Answer: A shooting star
82. I’m the technical term for a galaxy accelerating away from the Milky Way. Measuring me helps reveal the universe’s expansion rate.
Answer: Accelerating galaxy
83. I’m the giant cloud of gas created when galaxies collide and merge together into one larger entity.
Answer: Intergalactic medium
84. When the universe was a fraction of a second old, I was the incredibly brief period of exponential expansion at the outset.
Answer: Cosmic inflation
85. I’m the aptly named radiation that results when virtual particle pairs blink into existence and quickly annihilate.
Answer: Hawking radiation
86. When the nuclei of two or more atoms join, I’m the process that releases enormous amounts of energy.
Answer: Nuclear fusion
87. I’m the technical name for the effect causing light from distant galaxies to appear redder, explained by the universe’s expansion.
Answer: Redshift
88. I’m the puzzling observation that the most distant observable galaxies appear more mature and evolved than expected for their age.
Answer: Cosmic downsizing
89. Invisible to telescopes, I make up about 27% of the universe. Expanding space gives me a negative pressure that drives the cosmos’s swelling rate.
Answer: Dark energy
90. When black holes collide in distant galaxies, I’m the gravitational waves rippling across space-time.
Answer: Black hole mergers
91-99
91. When neutron stars crash together in cataclysmic explosions, I’m the gravitational spasms racing throughout the universe.
Answer: Gravitational waves
92. Albert Einstein called me “spooky action at a distance”. Quantum entanglement is the technical term for me.
Answer: Quantum non-locality
93. I’m the puzzling issue that most of the universe’s ordinary matter is invisible – probably locked up in stars, gas clouds and black holes.
Answer: Missing baryon problem
94. Split me and atoms fuse, join me and emissions are produced. At cosmic dawn I was split; now heavy elements are formed inside stars by my fusion.
Answer: Nuclei
95. When the energy of virtual particles fluctuates to separate them, I’m the tiny cosmological tear in spacetime that’s created, according to some theories.
Answer: Quantum foam
96. I’m the mysterious signal received in 1977 that seemed intelligent but has never been repeated or identified.
Answer: Wow! signal
97. I’m the unexplained dimming of starlight that indicates unknown masses of dark objects passing in front of distant stars.
Answer: Gravitational microlensing
98. I’m the strange phenomenon whereby light seems to bend and warp around extremely massive galaxy clusters.
Answer: Gravitational lensing
99. When black holes merge, I’m the powerful signal propagated through spacetime at light speed, vibrating strings of cosmic fabric.
Answer: Gravitational wave
