3.Universe & Solar System
· General Science/Everyday Science
30 MCQs
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1–20
of 30 MCQs
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1
What is the largest type of galaxy?
Answer:
Elliptical
Elliptical galaxies are the largest in the universe, ranging from small dwarf ellipticals to giant ones that can contain over a trillion stars and span hundreds of thousands of light-years. Unlike spiral galaxies, they have an approximately ellipsoidal shape and a smooth, nearly featureless brightness profile.
2
The Milky Way galaxy is classified as
Answer:
Spiral
The Milky Way is a barred spiral galaxy, characterized by a central bar-shaped structure composed of stars, surrounded by a disk of gas, dust, and stars that form distinct spiral arms. Our solar system is located within one of these arms, about 27,000 light-years from the galactic center.
3
What is at the center of most galaxies?
Answer:
Black hole
Most, if not all, massive galaxies are thought to harbor a supermassive black hole at their centers. These incredibly dense objects have a gravitational pull so strong that even light cannot escape, and they play a crucial role in the evolution and structure of the galaxies that surround them.
4
What is a light-year?
Answer:
Distance light travels in one year
A light-year is a unit of distance, not time. It represents the total distance that light travels in a vacuum in one Julian year (365.25 days), which is approximately 5.88 trillion miles or 9.46 trillion kilometers.
5
A supernova is
Answer:
An exploding star
A supernova is the powerful and luminous stellar explosion that occurs during the last evolutionary stages of a massive star. The explosion expels much or all of a star's material at great velocity, creating a shock wave that can trigger the formation of new stars.
6
What is a nebula?
Answer:
Cloud of gas and dust
A nebula is a giant cloud of dust and gas in space. Some nebulae come from the gas and dust thrown out by the explosion of a dying star, while others are regions where new stars are beginning to form, often referred to as 'star nurseries'.
7
Which galaxy is closest to the Milky Way?
Answer:
Andromeda
The Andromeda Galaxy (M31) is the closest large spiral galaxy to the Milky Way, located about 2.5 million light-years away. It is currently moving toward the Milky Way, and the two galaxies are expected to merge in about 4 to 5 billion years.
8
A black hole has gravity so strong that it can trap
Answer:
Light
A black hole is a region of spacetime where gravity is so intense that nothing—no particles or even electromagnetic radiation such as light—can escape from it. The boundary of the region from which no escape is possible is called the event horizon.
9
The Big Bang Theory explains
Answer:
The origin of the Universe
The Big Bang Theory is the prevailing cosmological model for the observable universe. It suggests that the universe began as a very hot, dense point and has been expanding for approximately 13.8 billion years.
10
Which is NOT a type of galaxy?
Answer:
Cubic
Galaxies are primarily classified by their visual morphology into spiral, elliptical, and irregular shapes. There is no such classification as a 'cubic' galaxy, as gravitational forces pull matter into rounded or disk-like configurations.
11
Stars are mostly made of
Answer:
Hydrogen and helium
Stars are massive spheres of plasma held together by gravity. They are primarily composed of hydrogen (about 70%) and helium (about 28%). The fusion of hydrogen into helium in the core provides the energy stars emit.
12
The lifecycle of a star ends as a
Answer:
White dwarf, neutron star, or black hole
Depending on its initial mass, a star will end its life as a white dwarf (low mass), a neutron star (massive stars), or a black hole (most massive stars) after exhausting its nuclear fuel.
13
What do we call the collection of billions of stars held by gravity?
Answer:
Galaxy
A galaxy is a massive, gravitationally bound system that consists of stars, stellar remnants, an interstellar medium of gas and dust, and dark matter. The Milky Way is our home galaxy.
14
Quasars are
Answer:
Energetic cores of distant galaxies
Quasars are the extremely bright and active centers of distant galaxies, powered by supermassive black holes actively consuming matter and releasing enormous energy across the electromagnetic spectrum.
15
Pulsars are
Answer:
Rotating neutron stars
Pulsars are highly magnetized, rapidly rotating neutron stars that emit beams of electromagnetic radiation. As they rotate, these beams sweep across Earth, appearing as regular pulses of radiation.
16
A constellation is
Answer:
A group of stars forming a pattern
A constellation is an area on the celestial sphere in which a group of visible stars forms a perceived outline or pattern. There are 88 officially recognized constellations representing various figures.
17
What force keeps galaxies together?
Answer:
Gravitational
Gravity is the fundamental force that holds galaxies together. It binds stars, gas, dust, and dark matter into the massive structures we observe throughout the universe.
18
Which is the most abundant element in the universe?
Answer:
Hydrogen
Hydrogen is the most abundant chemical element in the universe, making up roughly 75% of all normal matter. It was the first element created after the Big Bang and serves as the primary fuel for stars.
19
Red giants are
Answer:
Large, old stars
Red giants are stars in a late stage of stellar evolution. When a star exhausts the hydrogen in its core, it begins fusing hydrogen in a shell, causing the star to expand significantly and cool, giving it a reddish color.
20
What is the event horizon?
Answer:
Point around black hole where nothing escapes
The event horizon is the theoretical boundary surrounding a black hole. Once anything passes this 'point of no return,' the gravitational pull is so great that escape is impossible even at the speed of light.
