🚀 100 GK Questions on Space
Test your knowledge of the universe, planets, stars, galaxies, the Moon, the Sun, space exploration and astronomy.
Showing 100 questions
1Solar System
What is the name of our planetary system?
The Solar System.
2Solar System
How many planets are officially recognized in our Solar System?
Eight.
3Solar System
Which planet is closest to the Sun?
Mercury.
4Solar System
Which planet is farthest from the Sun among the eight planets?
Neptune.
5Solar System
What is the largest planet in the Solar System?
Jupiter.
6Solar System
What is the smallest planet in the Solar System?
Mercury.
7Solar System
Which planet is known for its prominent rings?
Saturn.
8Solar System
Which planet is known as the Red Planet?
Mars.
9Solar System
Which planet is sometimes called Earth’s twin because of its similar size?
Venus.
10Solar System
Which planet rotates on its side relative to its orbital plane?
Uranus.
11Solar System
Which planet has the strongest known winds in the Solar System?
Neptune.
12Solar System
What lies between the orbits of Mars and Jupiter?
The main asteroid belt.
13Solar System
What is the largest dwarf planet in the Solar System by diameter?
Pluto is the largest known dwarf planet by diameter, although Eris is more massive.
14Solar System
What is the region beyond Neptune containing many icy objects called?
The Kuiper Belt.
15Solar System
What is the distant spherical region thought to surround the Solar System and contain long-period comets?
The Oort Cloud.
16Planets
Which planet has the longest day among the eight planets?
Venus, if a day means one complete rotation relative to the stars.
17Planets
Which planet has the shortest year?
Mercury, which orbits the Sun in about 88 Earth days.
18Planets
Which planet has a Great Red Spot?
Jupiter.
19Planets
Which planet is the hottest in the Solar System?
Venus, because its dense carbon-dioxide atmosphere creates an extreme greenhouse effect.
20Planets
Which planet has the largest volcano in the Solar System?
Mars, home to Olympus Mons.
21Planets
What is Olympus Mons?
A gigantic shield volcano on Mars.
22Planets
Which planet has a day longer than its year?
Venus.
23Planets
Which planet is famous for its blue appearance caused partly by methane in its atmosphere?
Neptune.
24Planets
Which planet has the largest number of known moons as of the mid-2020s?
Saturn has the largest confirmed moon count as currently catalogued, though counts can change as new moons are discovered and confirmed.
25Planets
Which planet is covered by thick clouds of sulfuric acid?
Venus.
26Planets
Which planet has a prominent hexagonal storm pattern at its north pole?
Saturn.
27Planets
Which planet is the densest planet in the Solar System?
Earth.
28Planets
Which planet has a large canyon system called Valles Marineris?
Mars.
29Planets
Which planet has the most extreme axial tilt among the eight planets?
Uranus.
30Planets
Which planet has a very thin atmosphere made mostly of carbon dioxide?
Mars.
31Planets
Which planet is sometimes visible as a bright morning or evening object called the Morning Star or Evening Star?
Venus.
32Planets
Which planet has no solid surface and is composed mainly of hydrogen and helium?
Jupiter is a gas giant with no solid surface like Earth’s.
33Sun & Moon
What is the Sun?
A star at the center of our Solar System.
34Sun & Moon
What is the main element in the Sun?
Hydrogen.
35Sun & Moon
What process powers the Sun?
Nuclear fusion, primarily converting hydrogen into helium in its core.
36Sun & Moon
What is the natural satellite of Earth?
The Moon.
37Sun & Moon
Approximately how long does moonlight take to reach Earth?
About 1.3 seconds.
38Sun & Moon
Why does the Moon appear to change shape?
Because we see different portions of its sunlit side as it orbits Earth.
39Sun & Moon
What is a solar eclipse?
An event in which the Moon passes between Earth and the Sun and blocks some or all of the Sun’s disk from view.
40Sun & Moon
What is a lunar eclipse?
An event in which Earth passes between the Sun and Moon and Earth’s shadow falls on the Moon.
41Sun & Moon
What causes ocean tides mainly?
The gravitational effects of the Moon and the Sun, with the Moon being the stronger influence on Earth’s tides.
42Sun & Moon
What is a full moon?
The lunar phase when the Moon’s Earth-facing side is fully illuminated by the Sun.
43Sun & Moon
What is a new moon?
The lunar phase when the Moon is positioned roughly between Earth and the Sun and its illuminated side faces mostly away from Earth.
44Sun & Moon
How long does it take the Moon to orbit Earth relative to the stars?
About 27.3 days.
45Sun & Moon
How long is the lunar cycle from one new moon to the next?
About 29.5 days.
46Sun & Moon
Which spacecraft first carried humans to the Moon?
Apollo 11 was the first crewed mission to land humans on the Moon.
47Stars
What is a star?
A huge, self-luminous ball of plasma held together by gravity and powered mainly by nuclear fusion.
48Stars
What is the closest star to Earth?
The Sun.
49Stars
What is the closest star to the Sun?
Proxima Centauri.
50Stars
What is a supernova?
A powerful stellar explosion associated with certain stages of stellar evolution.
51Stars
What is a neutron star?
An extremely dense stellar remnant composed primarily of neutrons, formed from the collapsed core of certain massive stars.
52Stars
What is a pulsar?
A rapidly rotating neutron star that emits beams of electromagnetic radiation detected as regular pulses.
53Stars
What is a red giant?
A late stage of stellar evolution in which a star expands greatly after exhausting hydrogen in its core.
54Stars
What is a white dwarf?
A hot, dense stellar remnant left after a Sun-like star has shed its outer layers.
55Stars
What determines the color of a star?
Primarily its surface temperature. Hotter stars tend to appear bluer, while cooler stars tend to appear redder.
56Stars
What is a constellation?
A defined region of the sky or, traditionally, a recognizable pattern of stars.
57Stars
Which star is commonly called the North Star?
Polaris.
58Stars
Which constellation contains the North Star?
Ursa Minor, the Little Bear.
59Stars
What is the brightest star in Earth’s night sky, excluding the Sun?
Sirius.
60Galaxies
What is a galaxy?
A vast gravitationally bound system containing stars, gas, dust, dark matter and other objects.
61Galaxies
What galaxy contains our Solar System?
The Milky Way Galaxy.
62Galaxies
What type of galaxy is the Milky Way?
A barred spiral galaxy.
63Galaxies
Which galaxy is the nearest large galaxy to the Milky Way?
The Andromeda Galaxy.
64Galaxies
What is the Andromeda Galaxy also called?
Messier 31, or M31.
65Galaxies
What is at the center of the Milky Way?
A supermassive black hole called Sagittarius A*.
66Galaxies
What is a spiral galaxy?
A galaxy characterized by a flattened disk and spiral arms extending from its central region.
67Galaxies
What is an elliptical galaxy?
A galaxy with a smooth, roughly ellipsoidal shape and generally little cold gas and dust compared with spiral galaxies.
68Galaxies
What is a galaxy cluster?
A large group of galaxies bound together by gravity.
69Galaxies
What is a light-year?
A unit of distance equal to the distance light travels in one year.
70Galaxies
Approximately how fast does light travel through vacuum?
About 299,792 kilometers per second.
71Space Exploration
Who was the first human to travel into space?
Yuri Gagarin of the Soviet Union, in 1961.
72Space Exploration
Who was the first woman in space?
Valentina Tereshkova, in 1963.
73Space Exploration
Who was the first person to walk on the Moon?
Neil Armstrong.
74Space Exploration
Who was the second person to walk on the Moon?
Buzz Aldrin.
75Space Exploration
Which country launched Sputnik 1?
The Soviet Union.
76Space Exploration
What was Sputnik 1?
The world’s first artificial satellite, launched in 1957.
77Space Exploration
What does NASA stand for?
National Aeronautics and Space Administration.
78Space Exploration
What is India’s national space agency?
ISRO — Indian Space Research Organisation.
79Space Exploration
What was India’s first satellite?
Aryabhata, launched in 1975.
80Space Exploration
What was the name of India’s first lunar mission?
Chandrayaan-1.
81Space Exploration
What did Chandrayaan-1 help confirm on the Moon?
Evidence of water/hydroxyl molecules on the lunar surface.
82Space Exploration
What was Chandrayaan-3 notable for?
It successfully landed on the Moon in 2023, making India the fourth country to achieve a soft lunar landing and the first to land near the lunar south polar region.
83Space Exploration
What was India’s first successful Mars mission called?
Mars Orbiter Mission, commonly called Mangalyaan.
84Space Exploration
What is the International Space Station commonly called?
The ISS.
85Space Exploration
What is the Hubble Space Telescope?
A space-based observatory launched in 1990 that has made major astronomical observations across multiple wavelengths.
86Space Exploration
What is the James Webb Space Telescope designed primarily to study?
It observes the universe mainly in infrared wavelengths, studying objects ranging from early galaxies to stars, planets and planetary systems.
87Space Exploration
Which spacecraft carried humans to the Moon during the Apollo missions?
Apollo spacecraft were used for the crewed lunar missions.
88Astronomy
What is the study of objects and phenomena beyond Earth called?
Astronomy.
89Astronomy
What is a black hole?
A region of spacetime where gravity is so strong that nothing, including light, can escape once it passes the event horizon.
90Astronomy
What is the boundary around a black hole beyond which escape is impossible called?
The event horizon.
91Astronomy
What is a comet mainly made of?
A mixture of ice, dust and rocky material.
92Astronomy
What causes a comet’s visible tail?
Solar radiation and the solar wind cause material from the comet to form tails of gas and dust that generally point away from the Sun.
93Astronomy
What is an asteroid?
A relatively small rocky or metallic body orbiting the Sun.
94Astronomy
What is a meteor?
The streak of light produced when a meteoroid enters an atmosphere and heats up.
95Astronomy
What is a meteorite?
A space rock or fragment that survives passage through an atmosphere and reaches the ground.
96Astronomy
What is a nebula?
A large cloud of gas, dust and plasma in space.
97Astronomy
What is a supermassive black hole?
A black hole with a mass ranging from hundreds of thousands to billions of times the mass of the Sun, commonly found at the centers of large galaxies.
98Astronomy
What is dark matter?
Matter inferred from its gravitational effects that does not appear to interact significantly with light.
99Astronomy
What is dark energy?
The name given to the unknown component associated with the accelerated expansion of the universe.
100Astronomy
What is the Big Bang theory?
The leading scientific model describing the early hot, dense state of the universe and its subsequent expansion.
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