Astr 101 quiz 1

• Lightyear: It represents the distance that light travels in one year through the vacuum of space.
• Units are standardized quantities used to express measurements of physical quantities. They provide a way to quantify and communicate information about various properties or characteristics in a consistent manner
• AU(astronomical unit), the average distance between the earth and the sun. Disatnces within the solar system use the unit AU.
• Distance: km(objects), AU(orbits), Ly (between stars).
• Time: years (orbits), days (rotations/orbits), hours (rotations)
• Energy: Joule
• Power: Watt
• Temperature: Kelvin
• a local group refers to a small collection of galaxies that are gravitationally bound to each other.
• The term "local group" is commonly used to describe the immediate galactic neighborhood to which our Milky Way galaxy belongs.
• The Virgo supercluster is part of a network of other superclusters that are all gravitationally connected.
• The current best hypothesis of the structure of the universe is a web of matter connected together.
• Indirect knowledge uses devices.
• Direct knowledge provides a foundation for our immediate experiences, while indirect knowledge allows us to build upon and share information through more complex cognitive processes.
• The scientific method does not produce truth or facts, and can never be used to prove anything. the goal is to disprove things.
• Inductive reasoning is a form of reasoning in which general principles are inferred from specific observations or instances. It involves making conclusions about the broader category or generalization based on a limited set of specific observations.
• Deductive reasoning is a form of logical reasoning in which specific conclusions are drawn from general principles or premises. It is often described as a top-down approach, as it starts with a general statement or hypothesis and moves toward specific instances or predictions.
• Hypothesis: A hypothesis is a specific, testable statement or prediction that can be investigated and is often formulated to explain observations. It is a tentative explanation for a phenomenon or a question that can be tested through experimentation or further observation.
• • Theory: A scientific theory is a well-substantiated and comprehensive explanation of some aspect of the natural world. It is based on empirical evidence and has undergone extensive testing and scrutiny. A scientific theory is a broader, more established concept compared to a hypothesis.
• Hypothesis: Hypotheses are designed to be tested through experiments or further observations. They are falsifiable, meaning there is a possibility to prove them wrong through empirical evidence.
• Theory: While theories are also testable, they are typically not tested in the same way as hypotheses. The testing of a theory often involves a broad range of observations, experiments, and empirical evidence accumulated over time.
• Hypothesis: A hypothesis is an early stage in the scientific method, where researchers propose an idea that can be tested through experimentation or observation.
• Theory: A scientific theory is a more advanced and refined stage in the scientific method. It represents a well-established and widely accepted explanation supported by extensive evidence.
• Scientific theories must be falsifiable, meaning that they can be tested and disproved.
• Experiments must be repeatable
• A falsifiable statement is a statement or hypothesis that can be proven false or shown to be incorrect through empirical evidence or observation.
• Simplicity: no unnecessary details, scientific theories should not make any unnecessary claims.
• elegance: tie in of multiple phenomena such that the resulting understanding is greater than the individual parts.
• All brightness is measures relative to Vega.
• 10x brighter = -2.5 magnitude
• 100x brighter = -5 magnitude
• smaller = brighter
• There are 88 constellations in western astronomy
• Constellations were useful in mapping out the night sky, to give reference to locations.
• Western views of constellations are dominated by greek and babylonian origins
• The stars of a constellations are based on their apparent magnitude.
• The celestial sphere is the apparent 2-d sky, as stars are too far away for depth perception.
• Asterisms: shapes that are not officially recognized as constellations.
• Zodiac constellations are the constellations that follow the path of the sun through the night sky.
• The celestial sphere is an imaginary spherical shell that surrounds the Earth and serves as a convenient way to visualize the positions of celestial objects in the sky. It is an abstract concept that simplifies the representation of stars, planets, and other celestial bodies as seen from Earth.