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IAAC — 2019 Final Round
Question 1
Most people use °C (degree Celsius) to measure everyday temperatures. Astronomers prefer to use K (Kelvin) to measure te...
Open questionIAAC — 2019 Final Round
Question 2
Mars might be a place for future human explorations. However, humans cannot breathe on the surface of Mars because the a...
Open questionIAAC — 2019 Final Round
Question 3
The two moons of Mars are called ...
Open questionIAAC — 2019 Final Round
Question 4
On which planet in our solar system can you find the Great Red Spot?
Open questionIAAC — 2019 Final Round
Question 5
The axis of the Earth is tilted at an angle of approximately ... relative to the orbital plane around the Sun.
Open questionIAAC — 2019 Final Round
Question 6
The Pleiades is an open star cluster that plays a role in many ancient stories and is well-known for containing ... brig...
Open questionIAAC — 2019 Final Round
Question 7
Previous IAAC rounds featured Proxima/Alpha Centauri as closest star(system) to the Earth. Which one is the second close...
Open questionIAAC — 2019 Final Round
Question 8
The visible part of the electromagnetic spectrum is between ...
Open questionIAAC — 2019 Final Round
Question 9
The constellation ... is a bright W-shaped constellation in the northern sky.
Open questionIAAC — 2019 Final Round
Question 10
What is the so-called bolometric luminosity in astronomy?
Open questionIAAC — 2019 Final Round
Question 11
The second cosmic velocity (or escape velocity) is the speed required by an object to escape the gravitational field of...
Open questionIAAC — 2019 Final Round
Question 12
The International Space Station (ISS) circles the Earth approximately 410 km above the ground. Find the best estimate fo...
Open questionIAAC — 2019 Final Round
Question 13
Find the best approximation for the surface temperature of the Sun:
Open questionIAAC — 2019 Final Round
Question 14
The four big moons of Jupiter are Callisto, Europa, Ganymede, and Io. Which one of them has the smallest distance to Jup...
Open questionIAAC — 2019 Final Round
Question 15
The name of the black hole in the center of our Milky Way is ...
Open questionIAAC — 2019 Final Round
Question 16
Approximately how far away is the Andromeda Galaxy?
Open questionIAAC — 2019 Final Round
Question 17
When was the telescope invented by Galileo?
Open questionIAAC — 2019 Final Round
Question 18
The astronomical unit parsec (pc) plays a crucial role in astronomy. One parsec is equal to about 3.26 light-years. How...
Open questionIAAC — 2019 Final Round
Question 19
The picture below shows a very famous nebula: What is the name of this nebula?
Open questionIAAC — 2019 Final Round
Question 20
The star Betelgeuse is one of the brightest stars in the night sky with remarkable red color. In which constellation is...
Open questionIAAC — 2019 Final Round
Question 21
What does the astronomical term ecliptic describe?
Open questionIAAC — 2019 Final Round
Question 22
Approximately how long does it take Pluto to orbit the Sun once?
Open questionIAAC — 2019 Final Round
Question 23
Sunspots are black regions that temporarily appear on the Sun. Their number highly increases every ... years. This perio...
Open questionIAAC — 2019 Final Round
Question 24
The Large Magellanic Cloud is ...
Open questionIAAC — 2019 Final Round
Question 25
The Milky Way is part of a giant supercluster with a diameter of 160 Mpc. What is the name of this supercluster?
Open questionIAAC — 2019 Final Round
Question 26
Why are Cepheid stars relevant for astronomers?
Open questionIAAC — 2019 Final Round
Question 27
What type of radiation causes a black hole to evaporate over time?
Open questionIAAC — 2019 Final Round
Question 28
In astronomy, the concept of black bodies is very important to better calculate the radiation of stars. Which one is the...
Open questionIAAC — 2019 Final Round
Question 29
One astronomical unit (AU) is equal to approximately ...
Open questionIAAC — 2019 Final Round
Question 30
Radio telescopes are crucial for astronomical observations. Which one of these well-known radio telescopes has the large...
Open questionIAAC — 2019 Final Round
Question 31
Which one of these constellations is not located along the Milky Way in the sky?
Open questionIAAC — 2019 Final Round
Question 32
A comet’s tail points in the following direction:
Open questionIAAC — 2019 Final Round
Question 33
As the life of a star progresses, heavy elements are produced. The elements form layers around the star in this order (s...
Open questionIAAC — 2019 Final Round
Question 34
The so-called dark energy is a model to explain ...
Open questionIAAC — 2019 Final Round
Question 35
As a star collapses at the end of its life, the triple-alpha reaction takes place. Which one of these equations describe...
Open questionIAAC — 2019 Final Round
Question 36
Besides large astronomical objects, astrophysicists are also interested in small particles from space. Which one of thes...
Open questionIAAC — 2019 Final Round
Question 37
The term Schwarzschild radius usually describes properties of ...
Open questionIAAC — 2019 Final Round
Question 38
What is the correct numerical value and unit of the Boltzmann constant?
Open questionIAAC — 2019 Final Round
Question 39
What is true for a type-Ia (“type one-a”) supernova?
Open questionIAAC — 2019 Final Round
Question 40
The famous Drake equation attempts to answer the following question:
Open questionIAAC — 2020 Final Round
Question 1
How many parsecs are approximately 23 light years?
Open questionIAAC — 2020 Final Round
Question 2
Which one is the biggest moon of Jupiter?
Open questionIAAC — 2020 Final Round
Question 3
Which object was investigated by the Cassini research mission?
Open questionIAAC — 2020 Final Round
Question 4
What is the distinctive color of the star Betelgeuse?
Open questionIAAC — 2020 Final Round
Question 5
The International Space Station circles the Earth approximately every ...
Open questionIAAC — 2020 Final Round
Question 6
The well-known Hyades star cluster is located in the constellation ...
Open questionIAAC — 2020 Final Round
Question 7
What is the diameter of the Sun approximately?
Open questionIAAC — 2020 Final Round
Question 8
The planet Jupiter orbits the Sun in ...
Open questionIAAC — 2020 Final Round
Question 9
The value of the Hubble constant is approximately ...
Open questionIAAC — 2020 Final Round
Question 10
The first gravitational wave GW150914 was detected by using a Michelson interferometer with an arm length of ...
Open questionIAAC — 2020 Final Round
Question 11
The Event Horizon Telescope is a very long baseline interferometry array observing at a wavelength of ...
Open questionIAAC — 2020 Final Round
Question 12
Light with a wavelength of 100 micrometres is called ...
Open questionIAAC — 2020 Final Round
Question 13
How high above the Earth’s equator is the geostationary orbit located?
Open questionIAAC — 2020 Final Round
Question 14
Voyager 1 is the most distant man-made object. How fast is Voyager 1 moving away from the Sun at the moment?
Open questionIAAC — 2020 Final Round
Question 15
When was the dwarf planet Pluto discovered?
Open questionIAAC — 2020 Final Round
Question 16
How many times more mass has the Earth compared to the Moon?
Open questionIAAC — 2020 Final Round
Question 17
What does the astronomical term barycentre describe?
Open questionIAAC — 2020 Final Round
Question 18
How many Lagrange points exist in a two-body system?
Open questionIAAC — 2020 Final Round
Question 19
The astronomical term axial precession describes the changing ...
Open questionIAAC — 2020 Final Round
Question 20
Which astronomical term describes the alignment of three celestial objects?
Open questionIAAC — 2020 Final Round
Question 21
The farthest point of a planet to the Sun is called ...
Open questionIAAC — 2020 Final Round
Question 22
What is a synodic month?
Open questionIAAC — 2020 Final Round
Question 23
The astronomical object Hale-Bopp is a ...
Open questionIAAC — 2020 Final Round
Question 24
The Olbers’ paradox raises the following question:
Open questionIAAC — 2020 Final Round
Question 25
The picture below shows a very close and well-known galaxy: What is the name of this galaxy?
Open questionIAAC — 2020 Final Round
Question 26
The correct astronomical term for shooting stars (or falling star) is ...
Open questionIAAC — 2020 Final Round
Question 27
The calculated age of the universe is ...
Open questionIAAC — 2020 Final Round
Question 28
What is expected to happen at the end of the Sun’s lifetime?
Open questionIAAC — 2020 Final Round
Question 29
Approximately how far away is the Sun from the centre of the Milky Way?
Open questionIAAC — 2020 Final Round
Question 30
Which one is the correct order of spectral classes according to the star’s surface temperature (from high to low)?
Open questionIAAC — 2020 Final Round
Question 31
A rocket that has accelerated to the second cosmic velocity can...
Open questionIAAC — 2020 Final Round
Question 32
What is the diameter of the observable universe in parsec?
Open questionIAAC — 2020 Final Round
Question 33
The well-known and very large volcano named Olympus Mons is located on ...
Open questionIAAC — 2020 Final Round
Question 34
About how many Earth days are one Mars day?
Open questionIAAC — 2020 Final Round
Question 35
The fascinating aurorae (or polar lights) are located in the ...
Open questionIAAC — 2020 Final Round
Question 36
In which year did humans first land and walk on the Moon?
Open questionIAAC — 2020 Final Round
Question 37
The term heliocentric means ...
Open questionIAAC — 2020 Final Round
Question 38
Saturn’s moon Titan has many lakes which are made of liquid ...
Open questionIAAC — 2020 Final Round
Question 39
Copernicus is located on our moon and refers to a well-known ...
Open questionIAAC — 2020 Final Round
Question 40
What type of nebula is the famous Orion Nebula?
Open questionIAAC — 2020 Final Round
Question 41
How is the path in the sky called that the Sun appears to cross within a year?
Open questionIAAC — 2020 Final Round
Question 42
Spectral line splitting caused by magnetic fields is called ...
Open questionIAAC — 2020 Final Round
Question 43
In which wavelengths is the cosmic background radiation concentrated?
Open questionIAAC — 2020 Final Round
Question 44
Kepler’s Laws state that the cube of a planet’s semi-major axis is proportional to the ...
Open questionIAAC — 2020 Final Round
Question 45
What is the astronomical term for the outer boundary of the Sun’s magnetic field?
Open questionIAAC — 2020 Final Round
Question 46
The angle between an inferior planet and the Sun when observed from Earth is called ...
Open questionIAAC — 2020 Final Round
Question 47
The summer solstice in the northern/southern hemisphere occurs in ...
Open questionIAAC — 2020 Final Round
Question 48
Absolute magnitude is a star’s apparent magnitude in a distance of ...
Open questionIAAC — 2020 Final Round
Question 49
What is the visible part of the Sun called?
Open questionIAAC — 2020 Final Round
Question 50
The average albedo of the Earth (planetary albedo) is between ...
Open questionIAAC — 2021 Final Round
Question 1
Which intense meteor shower peaks every year in August?
Open questionIAAC — 2021 Final Round
Question 2
The distance between two objects with equal mass is doubled. By how much does the gravitational force between the object...
Open questionIAAC — 2021 Final Round
Question 3
A spaceship accelerates at 150 m/s² from rest. How long does it take to reach a 1.2 km distant asteroid?
Open questionIAAC — 2021 Final Round
Question 4
What kind of radiation do pulsars emit?
Open questionIAAC — 2021 Final Round
Question 5
The gravitational potential energy E between two objects with a distance R to each other can be expressed as ...
Open questionIAAC — 2021 Final Round
Question 6
What instrument is commonly used to observe and study pulsars?
Open questionIAAC — 2021 Final Round
Question 7
What type of astronomical object are pulsars most commonly?
Open questionIAAC — 2021 Final Round
Question 8
The two coordinate axis of the Equatorial Coordinate System are called ...
Open questionIAAC — 2021 Final Round
Question 9
The Vernal equinox is the intersection point between ...
Open questionIAAC — 2021 Final Round
Question 10
The closest star system to the Earth is called Alpha Centauri. How many stars belong to the Alpha Centauri system?
Open questionIAAC — 2021 Final Round
Question 11
The picture below shows a satellite galaxy of the Milky Way: What is the name of this satellite galaxy?
Open questionIAAC — 2021 Final Round
Question 12
Stars from which spectral type have the lowest temperature?
Open questionIAAC — 2021 Final Round
Question 13
Which one of the following expressions is the Rankine-Hugoniot jump condition for the conservation of momentum through a...
Open questionIAAC — 2021 Final Round
Question 14
Which one of the following expressions is correct for the Lorentz factor γ and β = v/c?
Open questionIAAC — 2021 Final Round
Question 15
The intergalactic medium is permeated mainly by ...
Open questionIAAC — 2021 Final Round
Question 16
In a far-away solar system, a planet circles the main star with an orbital period of 100 days and a semi-major axis of 2...
Open questionIAAC — 2021 Final Round
Question 17
How is the part of a moon’s shadow called in which a total solar eclipse is possible?
Open questionIAAC — 2021 Final Round
Question 18
The diameter of the lens’ aperture of your telescope is 5 m and you observe at a wavelength of 1000 nm. What is the reso...
Open questionIAAC — 2021 Final Round
Question 19
A fast travelling spaceship has a Lorentz factor of γ = 3. This corresponds to a velocity v of ...
Open questionIAAC — 2021 Final Round
Question 20
Imagine that a total solar eclipse happens on the Earth today. What is the phase of the Moon on this day?
Open questionIAAC — 2021 Final Round
Question 21
The negative effect of incoming wavefront distortions on telescope images is reduced by using a system called ...
Open questionIAAC — 2021 Final Round
Question 22
You are given a list of stars and their apparent magnitude. Which one is the faintest star?
Open questionIAAC — 2021 Final Round
Question 23
The right ascension is measured in units of ...
Open questionIAAC — 2021 Final Round
Question 24
The Lyman-alpha line can be found at a wavelength of around ...
Open questionIAAC — 2021 Final Round
Question 25
Which transition is called Lyα lines?
Open questionIAAC — 2021 Final Round
Question 26
Below, you can see the rough sketch of a telescope. What type of telescope is drawn?
Open questionIAAC — 2021 Final Round
Question 27
An Analemma is a diagram showing the position of _____ from a fixed location and the same mean solar time over the cours...
Open questionIAAC — 2021 Final Round
Question 28
Which astronomical coordinate system uses the observer on Earth as a reference point?
Open questionIAAC — 2021 Final Round
Question 29
Which type of star is only stable due to the pressure of an electron gas?
Open questionIAAC — 2021 Final Round
Question 30
The colour of a star depends on the ...
Open questionIAAC — 2021 Final Round
Question 31
An object is moving with a velocity of 0.6c in your line of sight. What is the redshift z of this object?
Open questionIAAC — 2021 Final Round
Question 32
In which one of the following time frames after the Big Bang did the cosmic reionization process begin?
Open questionIAAC — 2021 Final Round
Question 33
Massive stars are essential for the universe because they ...
Open questionIAAC — 2021 Final Round
Question 34
The drawing below shows a comet in four positions around the Sun. For which position does the comet’s tail point in the...
Open questionIAAC — 2021 Final Round
Question 35
What spectral region can be observed from the Earth even when there are clouds in the sky?
Open questionIAAC — 2021 Final Round
Question 36
What was the last planet visited by Voyager 1?
Open questionIAAC — 2021 Final Round
Question 37
The time between two full moons is approximately ...
Open questionIAAC — 2021 Final Round
Question 38
Which one of the following objects is called a black dwarf in astronomy?
Open questionIAAC — 2021 Final Round
Question 39
Which planet has an axial tilt of 98 degrees?
Open questionIAAC — 2021 Final Round
Question 40
The smallest distance between Pluto and the Sun is about ...
Open questionIAAC — 2022 Final Round
Question 1
What is the name of the JWST component highlighted below?
Open questionIAAC — 2022 Final Round
Question 2
What is the name of the JWST component highlighted below?
Open questionIAAC — 2022 Final Round
Question 3
What is the name of the JWST component highlighted below?
Open questionIAAC — 2022 Final Round
Question 4
When a neutron star rotates, it becomes a ...
Open questionIAAC — 2022 Final Round
Question 5
If the Earth had the density of a neutron star, what would be the diameter of the Earth?
Open questionIAAC — 2022 Final Round
Question 6
Where in space is the JWST located?
Open questionIAAC — 2022 Final Round
Question 7
Two asteroids with masses m₁, m₂ and velocities v₁, v₂ collide horizontally and merge into a single object. What is the...
Open questionIAAC — 2022 Final Round
Question 8
Which one of these wavelengths is considered ultraviolet radiation?
Open questionIAAC — 2022 Final Round
Question 9
Which one of these wavelengths is considered infrared radiation?
Open questionIAAC — 2022 Final Round
Question 10
The planet’s albedo is the fraction of incident light ...
Open questionIAAC — 2022 Final Round
Question 11
Earth’s current average surface temperature is around ...
Open questionIAAC — 2022 Final Round
Question 12
Which of the following acronyms refers to an instrument of the JWST?
Open questionIAAC — 2022 Final Round
Question 13
A star has the luminosity L₀. The temperature T of the star doubles. How does the luminosity change?
Open questionIAAC — 2022 Final Round
Question 14
An object emits light at a wavelength of 200 nanometers. You receive the light at 1000 nanometers. What is the redshift...
Open questionIAAC — 2022 Final Round
Question 15
Why is it hard to observe the universe with infrared radiation from the Earth’s surface?
Open questionIAAC — 2022 Final Round
Question 16
The moment of inertia of a solid cylinder with radius R and mass M is given by ...
Open questionIAAC — 2022 Final Round
Question 17
Kepler’s 2nd law states that ...
Open questionIAAC — 2022 Final Round
Question 18
Scientists detect no CH₃OH and no NH₃ in the atmosphere of a sub-Neptune planet. What type of surface does this planet p...
Open questionIAAC — 2022 Final Round
Question 19
Sub-Neptune planets are ...
Open questionIAAC — 2022 Final Round
Question 20
The surface temperature (in °C) of the Sun is close to ...
Open questionIAAC — 2022 Final Round
Question 21
An object’s spectral energy distribution (SED) is formally given by ...
Open questionIAAC — 2022 Final Round
Question 22
Galileo discovered with his telescope that Venus ...
Open questionIAAC — 2022 Final Round
Question 24
Neptune’s diameter is similar to ...
Open questionIAAC — 2022 Final Round
Question 25
Compared to the Sun’s surface temperature, sunspots are ...
Open questionIAAC — 2022 Final Round
Question 26
The brightest star in the night sky is called ...
Open questionIAAC — 2022 Final Round
Question 27
Alpha Centauri is the closest star system to the Earth. It is located on the ...
Open questionIAAC — 2022 Final Round
Question 28
The atmosphere of Venus contains high amounts of ...
Open questionIAAC — 2022 Final Round
Question 29
What is the name of Jupiter’s moon shown in the figure below?
Open questionIAAC — 2022 Final Round
Question 30
The moon Titan orbits around ...
Open questionIAAC — 2023 Final Round
Question 1
Which one of these shapes (shown below) illustrates an elliptical galaxy?
Open questionIAAC — 2023 Final Round
Question 2
What is the class of the galaxy shown below?
Open questionIAAC — 2023 Final Round
Question 3
Which class of galaxies does the shape shown below illustrate?
Open questionIAAC — 2023 Final Round
Question 4
The speed of light is approximately ...
Open questionIAAC — 2023 Final Round
Question 5
What is the most common type of galaxy in the universe?
Open questionIAAC — 2023 Final Round
Question 6
How far away from Earth is a star with an observed parallax of 0.1 arcseconds?
Open questionIAAC — 2023 Final Round
Question 7
Which one of the labeled points on the ellipse shown below is the aphelion?
Open questionIAAC — 2023 Final Round
Question 8
What is true about the orbit of a comet called C/2023 A3?
Open questionIAAC — 2023 Final Round
Question 9
The term dark energy is related to ...
Open questionIAAC — 2023 Final Round
Question 10
Which landforms near the Zhurong landing site on Mars are likely related to volcanism?
Open questionIAAC — 2023 Final Round
Question 11
The gravitational acceleration at the surface of a star with average density ρ and radius R is given by ...
Open questionIAAC — 2023 Final Round
Question 12
The Zhurong Mars rover landed at an elevation of around ...
Open questionIAAC — 2023 Final Round
Question 13
Which instrument onboard the Zhurong Mars rover measures the magnetic field?
Open questionIAAC — 2023 Final Round
Question 14
Which object was historically the reference value m₀ for the apparent magnitude?
Open questionIAAC — 2023 Final Round
Question 15
About how much brighter is a star with an apparent magnitude of m = 1 compared to a star with an apparent magnitude of m...
Open questionIAAC — 2023 Final Round
Question 16
Hydrostatic equilibrium can best be described as the equilibrium between ...
Open questionIAAC — 2023 Final Round
Question 17
The ideal gas law states that ... (T: temperature, p: pressure, V: volume, N: number of particles, k: Boltzmann constant...
Open questionIAAC — 2023 Final Round
Question 19
Where on Mars did the Zhurong rover of the Tianwen-1 mission land?
Open questionIAAC — 2023 Final Round
Question 20
The colour of light with a wavelength of 700 nanometers is ...
Open questionIAAC — 2023 Final Round
Question 21
How high was the star formation rate in the Galactic Center in the past 10–100 billion years?
Open questionIAAC — 2023 Final Round
Question 22
The two young massive clusters near the Galactic Centre are called ...
Open questionIAAC — 2023 Final Round
Question 23
How far away is the centre of the Milky Way from Earth?
Open questionIAAC — 2023 Final Round
Question 24
The atmosphere of Mars consists primarily of ...
Open questionIAAC — 2023 Final Round
Question 25
Approximately how many stars are there in the Milky Way?
Open questionIAAC — 2023 Final Round
Question 26
The bending of starlight when it passes through a gravitational field is called ...
Open questionIAAC — 2023 Final Round
Question 27
The outermost layer of the Sun that is visible during a total solar eclipse is called the ...
Open questionIAAC — 2023 Final Round
Question 28
The fusion process that generates the Sun’s energy is called ...
Open questionIAAC — 2023 Final Round
Question 29
How does the temperature of a star affect the distribution of photon energies it emits?
Open questionIAAC — 2023 Final Round
Question 30
The asteroid belt of the solar system is between the orbits of ...
Open questionIAAC — 2024 Final Round
Question 1
Which one of these stars can be seen only in the Southern Hemisphere?
Open questionIAAC — 2024 Final Round
Question 2
Which one of these constellations can be seen only in the Southern Hemisphere?
Open questionIAAC — 2024 Final Round
Question 3
What kind of astronomical object is the Large Magellanic Cloud?
Open questionIAAC — 2024 Final Round
Question 4
How many stars are there in the Milky Way?
Open questionIAAC — 2024 Final Round
Question 5
On Earth’s surface, objects fall with a gravitational acceleration of approximately ...
Open questionIAAC — 2024 Final Round
Question 6
The cosmic microwave background can be detected using a ...
Open questionIAAC — 2024 Final Round
Question 7
The rotational speed at Earth’s equator is about 1,600 km/h. What is the rotational speed at Earth’s poles?
Open questionIAAC — 2024 Final Round
Question 8
Which latitude is best suited for a rocket launch?
Open questionIAAC — 2024 Final Round
Question 9
The altitude of the International Space Station (ISS) is around ...
Open questionIAAC — 2024 Final Round
Question 10
The ISS descends over time primarily due to ...
Open questionIAAC — 2024 Final Round
Question 11
Space is often considered to start at an altitude of ...
Open questionIAAC — 2024 Final Round
Question 12
What is the name of the region marked in the horizontal Milky Way drawing below?
Open questionIAAC — 2024 Final Round
Question 13
What is the name of the region marked in the horizontal Milky Way drawing below?
Open questionIAAC — 2024 Final Round
Question 14
Einstein rings are caused by ...
Open questionIAAC — 2024 Final Round
Question 15
What is the initial mass function (IMF) in astronomy?
Open questionIAAC — 2024 Final Round
Question 16
What is a spectral energy distribution (SED) plot in astronomy?
Open questionIAAC — 2024 Final Round
Question 17
Io is a moon of the planet ...
Open questionIAAC — 2024 Final Round
Question 18
Which spacecraft orbits currently around Jupiter?
Open questionIAAC — 2024 Final Round
Question 19
How do volcanoes at the poles of the moon Io differ from volcanoes at the equator?
Open questionIAAC — 2024 Final Round
Question 20
How many volcanic hot spots were observable on the surface of the moon Io between 2017 and 2022?
Open questionIAAC — 2024 Final Round
Question 21
Which mechanism causes volcanic activity on the moon Io?
Open questionIAAC — 2024 Final Round
Question 22
How many people have stepped on the moon as of 2024?
Open questionIAAC — 2024 Final Round
Question 23
Which one of these planets is never visible at midnight?
Open questionIAAC — 2024 Final Round
Question 24
Schmidt, Cassegrain, and Galilean are names for famous ...
Open questionIAAC — 2024 Final Round
Question 25
Most stars are cooler than the Sun and emit most of their energy as ...
Open questionIAAC — 2024 Final Round
Question 26
Astronomers use Cepheid stars as a measurement for ...
Open questionIAAC — 2025 Final Round
Question 1
What type of optical telescope is shown in the image below?
Open questionIAAC — 2025 Final Round
Question 2
What type of optical telescope is shown in the image below?
Open questionIAAC — 2025 Final Round
Question 3
Approximately how large is the diameter of the Sun?
Open questionIAAC — 2025 Final Round
Question 4
What is the distance between the Sun and the closest star?
Open questionIAAC — 2025 Final Round
Question 5
If the Sun had a diameter of a football (22 cm), what would be Earth’s diameter on this scale?
Open questionIAAC — 2025 Final Round
Question 6
One astronomical unit (AU) is equivalent to approximately ...
Open questionIAAC — 2025 Final Round
Question 7
What is the average density of the planet Earth?
Open questionIAAC — 2025 Final Round
Question 8
The gravitational acceleration experienced by an object of mass m at the surface of a planet with mass M and radius R eq...
Open questionIAAC — 2025 Final Round
Question 9
The Hubble parameter H(t) is connected to the cosmological scale factor a(t) by ...
Open questionIAAC — 2025 Final Round
Question 10
The unit of the Hubble constant H₀ is usually given as ...
Open questionIAAC — 2025 Final Round
Question 11
The current age of the universe is ...
Open questionIAAC — 2025 Final Round
Question 12
What are the two main components of comets?
Open questionIAAC — 2025 Final Round
Question 13
What are the two tails of a comet mainly made of?
Open questionIAAC — 2025 Final Round
Question 14
If the distance to a star doubles, the gravitational force it exerts becomes ...
Open questionIAAC — 2025 Final Round
Question 15
Cepheid variables are primarily important because they allow astronomers to measure ...
Open questionIAAC — 2025 Final Round
Question 16
If a Cepheid has a period of 30 days, compared to a 6-day Cepheid, it will be ...
Open questionIAAC — 2025 Final Round
Question 17
The distance modulus relates which two quantities?
Open questionIAAC — 2025 Final Round
Question 18
A star has an absolute magnitude of -2.0 and is located 1000 pc away. What is its apparent magnitude?
Open questionIAAC — 2025 Final Round
Question 19
A star has an apparent magnitude of 10.0 and is located 100 pc away. What is its absolute magnitude?
Open questionIAAC — 2025 Final Round
Question 20
The question of why the night sky is dark despite the vast number of stars is known as ...
Open questionIAAC — 2025 Final Round
Question 21
Why is the night sky dark, even though the universe contains billions of stars?
Open questionIAAC — 2025 Final Round
Question 22
In cosmology, the critical density determines ...
Open questionIAAC — 2025 Final Round
Question 23
If the density of the universe is smaller than the critical density, the universe is ...
Open questionIAAC — 2025 Final Round
Question 24
The Milky Way-Andromeda collision probability is mainly influenced by which smaller galaxies?
Open questionIAAC — 2025 Final Round
Question 25
Which galaxy tends to increase the probability of a Milky Way-Andromeda collision?
Open questionIAAC — 2025 Final Round
Question 26
Gravitational softening in simulations is introduced to ...
Open questionIAAC — 2025 Final Round
Question 27
The galaxy M31 is also called ...
Open questionIAAC — 2025 Final Round
Question 28
Which two galaxies are the dominant members of the Local Group?
Open questionIAAC — 2025 Final Round
Question 29
What is the currently expected timescale for a possible Milky Way-Andromeda merger?
Open questionIAAC — 2025 Final Round
Question 30
The perihelion distance is defined as ...
Open questionIAAC — 2025 Final Round
Question 31
The discovery of the object Ammonite (2023 KQ 14) was significant because it fills the ...
Open questionIAAC — 2025 Final Round
Question 32
The newly discovered Sedna-like object ‘Ammonite’ has a perihelion of ...
Open questionIAAC — 2025 Final Round
Question 33
Which hypothetical body is often proposed to explain Sedna-like orbits?
Open questionIAAC — 2025 Final Round
Question 34
Which element is most abundant in the universe?
Open questionIAAC — 2025 Final Round
Question 35
Which star will the Sun most likely become at the end of its life?
Open questionIAAC — 2025 Final Round
Question 36
Which planet has the fastest rotation period?
Open question