Astronomy Ch 1

the galaxy in which the sun and solar system reside

Milky Way galaxy

The principle that the simplest hypothesis is the most likely, named after William of Occam, the Medieval English cleric to whom the idea is attributed.

Occam's razor

How many galaxies are in the Local Group? A. a few B. a few dozen C. a few hundred D. a few thousand

a few dozen

when you see a pattern in nature, it is usually evidence of:

an underlying physical law

An interdisciplinary science combining astronomy, biology, chemistry, geology, and physics to study life in the cosmos.

astrobiology

The belief that the positions and aspects of stars and planets influence human affairs and characteristics, as well as terrestrial events.

astrology

The average distance from the sun to earth: approximately 150 million kilometers

astronomical unit (AU)

the scientific study of planets, stars, galaxies, and the universe as a whole

astronomy

The smallest unit of a chemical element that retains the properties of that element. Each atom is composed of a nucleus (neutrons and protons) surrounded by a cloud of electrons.

atom

astronomical unit

au

The event that occurred 13.8 billion years ago that marks the beginning of time and the universe.

big bang

The number by which one quantity is multiplied to get another number.

constant of proportionality

The (testable) assumption that the same physical laws that apply here and now also apply everywhere and at all times and that the universe has no special locations or directions.

cosmological principle

At which point does the distance make a huge jump in scale? A. Earth to Sun B. Sun to Neptune C. Sun to closest star D. diameter of the Milky Way Galaxy

diameter of the Milky Way Galaxy

a hypothesis shown to be false

falsified

The scientific method is a process by which scientists:

gain confidence in theories by failing to prove them wrong

a well considered idea, based on scientific principles and knowledge, that leads to testable predictions.

hypothesis

ly

light year

the group of galaxies that include the Milky Way and Andromeda galaxies

local group

Which discipline is used to analyze patterns and communicate complex material? A. chemistry B. language C. mathematics

mathematics

Rank the steps of the scientific method in order from start to finish. A. forming hypotheses B. making observations C. making predictions D. testing theories

observation, hypothesis, prediction, test theories

A broad statement that predicts a particular aspect of how the physical universe behaves and that is supported by many empirical tests.

physical law

A general idea or sense about the universe that guides us in constructing new scientific theories. Principles can be testable theories.

principle

A relationship between two things whose ratio is a constant

proportionality

The relationship in quantity or size between two or more things.

ratio

The formal procedure- including hypothesis, prediction, and experiment or observation- used to test (that is, to attempt to falsify) the validity of scientific hypotheses and theories.

scientific method

The standard expression of numbers with one digit (which can be zero) to the left of the decimal point and multiplied by 10 to the exponent required to give the number its correct value.

scientific notation

the gravitationally bound system made up of the sun, planets, dwarf planets, moons, asteroids, comets, and Kuiper belt objects, along with their associated gas and dust.

solar system

A luminous ball of gas held together by gravity. A normal star is powered by nuclear reactions in its interior.

star

the star at the center of the solar system

sun

a large conglomeration of galaxy clusters and galaxy groups, typically more than 100-300 megaparsecs (Mac) in size and containing tens of thousands to hundreds of thousands of galaxies.

supercluster

Rank the following in order of size from smallest to largest. A. a light-minute B. a light-year C. a light-hour D. the radius of Earth E. the distance from Earth to the Sun F. the radius of the Solar System

the radius of the earth, a light minute, the distance from earth to the sun, a light-hour, the radius of the solar system, a light-year.

A description of the properties of a particular object or system in terms of known physical laws or theories; often, a computer calculation of predicted properties based on such a description

theoretical model

Which of the following is the highest level of scientific knowledge? A. hypothesis B. observation C. theory

theory

a well-developed idea or group of ideas that are tied solidly to known physical laws and make testable predictions about the world. A very well-tested theory may be called a physical law, or simply a fact.

theory

a fundamental quantity fo measurement. The meter is an example of a metric unit; the foot is an example of an English unit.

unit

All of space and everything contained therein. our own universe in a collection of parallel universes that together make up all that exists.

universe