Astronomy chapter 1 & 2

A star is 230 light years away. The light we see tonight from that star left it

230 years ago

The Renaissance astronomer who wrote the pioneering book that suggested the Earth probably orbits the Sun (instead of the other way around) was

Copernicus

The great astronomer of ancient times who summarized and improved a system of circles upon circles to explain the complicated motions of the planets (and published the system in a book now called The Almagest) is

Potelmy

Within a constellation, an even smaller, recognizable pattern of stars is often called

an asterism

The smallest piece of an element (like gold or lead) that still has all the properties of that element is called

an atom

The laws of nature as determined by science

are constructed from many observations, hypotheses, and experiments

How did Eratosthenes measure the size of the Earth?

by measuring the height of the Sun in the sky on the same day in two cities at different latitudes

The 88 sectors into which astronomers today divide the celestial sphere (the whole sky) are called

constellation

The way scientists know that a hypothesis in astronomy is a reasonable description of nature is to

do experiments and observations about the predictions of the hypothesis

When it comes to our place in the solar system today, which model do we accept?

heliocentric

The south celestial pole and the north celestial pole lie in the sky directly above

polaris

The Astronomical Unit (AU) as defined by astronomers is

the distance between the earth and the sun

A light year is

the distance that light travels in one year

The Sun's apparent path around the celestial sphere is called

the ecliptic

The celestial sphere turns once around each day because

the planet on which we live is rotating

In Ptolemy's system the planets orbit the Earth and not the Sun. How did the system explain the retrograde motion of planets like Jupiter?

the planets moved on a small circle whose center, in turn, circled a point near the Earth

The star that provides energy for life on Earth is

the sun