Questions and Answers
What is baryonic matter?
Ordinary matter consisting of protons, electrons, and neutrons that comprises atoms, planets, stars, galaxies, and other bodies.
What is dark matter?
Matter that has gravity but does not emit light.
What is dark energy?
A source of anti-gravity, a force that counteracts gravity and causes the universe to expand.
What is a protostar?
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What is a thermonuclear reaction responsible for?
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What are main sequence stars?
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What is a light year?
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How old is the universe?
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What is the predominant composition of the universe?
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Which of the following is not a theory that preceded the Big Bang Theory?
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Redshift refers to the phenomenon where light emitted by an object moving away appears to be shifted toward longer wavelengths.
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What phenomenon allows us to observe cosmic microwave background radiation?
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What primarily causes the universe to expand?
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When was the solar system formed in the age of the universe?
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Study Notes
Universe Composition
- Universe is at least 13.8 billion years old; Solar System is 4.5-4.6 billion years old.
- Comprises all space, time, matter, and energy.
- 4.6% baryonic matter: ordinary matter made of protons, electrons, neutrons forming atoms, planets, stars, and galaxies.
- 24% dark matter: invisible matter exerting gravitational forces but does not emit light, necessary for galaxy cohesion.
- 71% dark energy: a force causing the universe to expand, counteracting gravity.
- Fundamental elements in the universe include Hydrogen, Helium, and Lithium.
Stellar Formation
- Protostar: early stage of star formation from gravitational collapse of gases.
- Thermonuclear reaction: fusion process in stars producing energy by fusing hydrogen into helium.
- Main Sequence Stars: stars in a stable phase fusing hydrogen in their cores, balancing nuclear fusion's outward pressure with gravity.
Structures in the Universe
- Galaxy: Contains billions of stars, with diameters spanning 91 billion light years.
Theories of Universe Origin
- Ancient cultures presented various creation myths explaining the origin of the universe.
- Steady State Model, Primordial Universe, Cyclical Universe, Ptolemaic Universe, and Einsteinian Universe were proposed theories preceding the Big Bang Theory.
- Monotheistic religions attribute universe creation to a supreme being.
Big Bang Theory
- Widely accepted for explaining the universe’s expansion and origin.
- Redshift: phenomenon where light from distant objects shifts to longer wavelengths, indicating they are moving away, contributing to the understanding of an expanding universe.
- Cosmic Microwave Background (CMB): remnant radiation from the Big Bang, providing evidence for the universe's hot, dense initial state.
Evolution of the Universe
- Initial conditions: all matter and energy existed in a hot, dense state around 13.8 billion years ago.
- Rapid inflation occurred shortly after, leading to the formation of fundamental particles (quarks, hadrons, leptons).
- Big Bang nucleosynthesis: formation of protons, neutrons, and light elements (hydrogen, helium, lithium) occurred roughly within 20 minutes post-Big Bang.
- Universe cooled and transitioned to a matter-dominated period where photons decoupled from matter about 380,000 years later, leading to the release of CMB.
- Over 100 million years, initial cloud formations led to the birth of stars and subsequently galaxies.
- By 9.8 billion years after the Big Bang, dark energy began dominating the universe's dynamics, resulting in its accelerating expansion.
- Formation of the Solar System occurred approximately 9.8 billion years post-Big Bang.
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Description
Explore the fundamental concepts of the universe in this quiz, including baryonic matter, dark matter, and dark energy. Test your knowledge on the formation of stars from protostars to fully developed celestial bodies. Perfect for students diving into cosmology and astrophysics.
