Our Place In the Universe

Vocab for the textbook Understanding Our Universe by Stacy Palen and George Blumenthal 4th edition for Astronomy&101

Astronomy

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

Astronomical Unit (AU)

Average distance from Earth to the Sun. Approximately 150 million kilometers

Massive

Contains mass

Scientific Method

The formal procedure used to test (attempt to falsify) the validity of a scientific hypothesis and theories

Theory

A well developed (group of) ideas tied solidly to known physical laws and make testable predictions about the universe.

Idea

An untested notion about how something might be

Fact

An observation or measurement

Hypothesis

An idea that leads to testable predictions

Law

Series of observations that scientists that can use to make predictions with no explanation of why it occurs

Scientific Principle

A generalization about the universe that guides scientists in the construction of a new hypothesis; not independent of other principles

Light Time Travel

How long it would take for light to travel a given distance. Used do to it being the fastest possible speed, always the same speed, 300,000 kilometers/second

Light Year

The distance that light travels in one year, approximately 9.46 trillion kilometers. It is used to measure astronomical distances.

Big Bang

The leading explanation for the origin of the universe 13.8 billion years ago, suggesting it began as an extremely hot and dense point and has been expanding ever since.

In the beginning only Helium and Hydrogen existed with traces of Lithium, Beryllium, and Boron. These combined to make stars and galaxies, leading to the formation of heavier elements through nuclear fusion in stars.

Satellite

Object in orbit more massive than a body

Nuclear Diffusion (stars)

that emit light and heat due to nuclear fusion in their cores, serving as the building blocks of galaxies.

Nuclear Fusion (stars)

is the process where two light atomic nuclei combine to form a heavier nucleus, releasing energy in the process. It is the reaction that powers stars and produces heavier elements.

Cosmic Location

Universe ,Laniakea Supercluster, Virgo Supercluster, Local Group, Milky Way, Solar System, Earth

Waves

Radio, Microwave, Infared, Visible, Ultra Violet, X-ray, Gamma Ray

Falsified

The ability to be proven wrong

Occam’s Razor

When faced with competition hypothesis that explain all observations equally well, choose the one with the fewest assumptions, the simpler explanation

Cosmological Principle

The testable assumption that the same physical laws that apply here and now also apply everywhere and at all times; there is no special locations or directions in the universe