Questions and Answers
The absorption lines for helium for light coming from the Sun are shifted towards the ______ end as compared with those for a distant star.
red
The evidence for expansion contradicted the previously held view of a static and unchanging ______.
universe
The ______ Bang Theory describes the evolution of the universe.
Big
Cosmic ______ Background is a key piece of evidence for the Big Bang Theory.
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A protostar forms before a star enters the ______ sequence phase.
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The ______ state Model is one of the theories regarding the origin of the universe.
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Light travels a distance measured in ______ years across space.
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The universe is currently ______, implying it is expanding over time.
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Study Notes
Universe and the Solar System
- Comprised of various celestial bodies, including stars, planets, asteroids, and meteoroids.
- The solar system features the Sun at its center, surrounded by eight planets and their moons.
Baryonic Matter
- Refers to the ordinary matter that makes up stars, planets, and other visible astronomical entities.
- Accounts for about 4-5% of the total mass-energy content of the universe.
Dark Matter
- Constitutes approximately 27% of the universe’s total mass-energy.
- Cannot be observed directly but inferred from gravitational effects on visible matter and radiation.
Dark Energy
- Makes up around 68% of the universe and is responsible for its accelerated expansion.
- Its nature is still largely unknown, posing significant questions in cosmology.
Protostar
- A young star that is just beginning to form, around a molecular cloud.
- Forms through the gravitational collapse of gas particles, leading to increased pressure and temperature.
Thermonuclear Reaction
- The process that powers stars, including the Sun, through hydrogen fusion into helium.
- Releases vast amounts of energy, contributing to the star's heat and light.
Main Sequence Stars
- Stars that are in a stable phase of nuclear fusion, converting hydrogen into helium in their cores.
- Account for about 90% of all stars, including the Sun.
Light Years
- A unit of distance representing how far light travels in one year, roughly 5.88 trillion miles (9.46 trillion kilometers).
- Used to measure vast interstellar distances.
Expanding Universe
- The universe is constantly expanding, supported by the observation of redshift in distant galaxies.
- Redshift indicates that galaxies are moving away, providing evidence against the static universe theory.
Cosmic Microwave Background
- A relic radiation from the early universe, providing a snapshot of the infant universe roughly 380,000 years after the Big Bang.
- Uniformly fills the universe and supports the Big Bang theory.
Origin of the Universe
- Explored through various theories, including the Big Bang theory and the Steady State model.
- The Big Bang theory posits that the universe began as a singular explosion, leading to expansion and cooling.
Timeline of the Big Bang
- The evolution of the universe proceeds through stages, starting from the singularity to the formation of galaxies and large-scale structures.
- Key events include nucleosynthesis, the formation of atoms, and the emergence of cosmic structures.
Evolution of the Universe according to the Big Bang Theory
- The universe evolved from a hot, dense initial state to its present, cooler condition.
- Continues to expand at an accelerating rate, leading to the current understanding of cosmic evolution dynamics.
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Description
Test your knowledge on the universe and the solar system with this engaging quiz. Explore topics such as baryonic matter, dark matter, protostars, and the structure of the cosmos. Challenge yourself on various concepts related to the expanding universe and main sequence stars.
