Chapter 1 Flashcards
(22 cards)
Astronomy
the study of celestial objects such as moons, planets, stars, nebulas, and galaxies.
the Universe
the total of space, time, matter, and energy.
scientific notation
5 billion = 5x10^9
5 million = 5x10^6
0.005 = 5x10^-3
—using powers of ten to express hard to write down numbers
scientific notation rules
multiplication: multiply coefficients, add the exponents
division: divide coefficients, subtract the exponents
add+subt: only add or subtract directly if exponent is the same. otherwise, you need to manipulate them to make the exponents the same.
order of magnitude
each jump in the power of ten (the exponent)
planets
a body that orbits a star and is massive enough for self-gravity to have pulled it into a spherical shape and to have cleared smaller objects from the neighborhood of its orbit
come in two basic types: small spheres of rock like earth, or larger spheres of gas like jupiter
stars
balls of gas that produce energy by means of nuclear fusion in their cores.
planetary systems
a star and the planets that orbit it together.
galaxies
millions to billions of gravitationally bound stars. galaxies also include gas, dust, and dark matters.
galaxy clusters
a collection of hundreds or thousands of galaxies bound together by gravity.
supercluster
a collection of galaxy clusters; the largest type of object in the universe.
astronomical unit (AU)
the average distance from the sun to earth.
1 AU =1.5x10^11meters
used as a standard of measure for solar system objects.
light year (ly)
the distance light travels in a year: 9.5x10^15 meters. used as a standard of measure for large distances.
parsec (pc)
astronomers’ preferred unit for large distances. equal to 3.26 light years.
dust
the smallest bits of solid matter in the universe. composed of atoms such as carbon and silicon.
atoms
the fundamental building block of matter, consisting of a dense central nucleus surrounded by a cloud of negatively charged electrons.
subatomic particles
any particle smaller than an atom. including protons, neutrons, and electrons.
scientific method
theory
an explanation for a phenomenon that has undergone extensive testing and is generally accepted to be accurate
pseudoscience
a claim, belief, or practice that is presented as scientific but does not adhere to a valid scientific method, lacks supporting evidence or plausibility, and/or cannot be reliably tested
astrology
the belief that there is a relationship between astronomical phenomena and events in the human world.
climate change
a significant, long term change in the statistical distribution of weather patterns
