Astronomy Test

What is geocentric?

The Aristotle (Greek) BC used an earth centered model of the solar system.

Who is Ptolemy (Egyptian) BC. What did he do?

He added epicycles to the geocentric model making it more complex.

Who is Nicholas Copernicus (Polish) 1543?

He proposed a sun centered model of the solar system ( heliocentric)

Who is Galilei Galileo (Italian)?

Found out sun spots, mountains on the moon, saturns rings etc. using a telescope. He supported the heliocentric model.

Who is Johannes Kepler?

Found out that the planets orbit were ellipses, not circles.

Who is Issac Newton?

Discovered gravity, orbits were discovered. Discovered Uranus, Neptune, and Pluto.

What is the zenith?

The point directly above the observer on the celestial sphere.

what is the nadir?

The point directly below the observer on the celestial sphere.

What is Ecliptic?

The path of the sun in the celestial sphere that is seen from the earth.

How much is one astronomical unit (au)?

93 mil miles.

How much is one light year?

9.46 km

What is a comet?

A comet is a celestial object that is made from. rocks, ice, water, and frozen gases.

What is a meteor?

A mete

What is an equinox?

When the sun is directly above the equator, this happens twice a year.

When does spring start ( vernal)?

March 21st

When does fall start? ( Autumnal)

It starts september 21

What is the asteroid belt?

The asteroid belt is located between the orbits of Mars and Jupiter. It is composed of dwarf plants. rocks and small pebbles.

What is the difference between a meteor, meteorite, meteoroid

A meteor is a streak of light when a meteoroid enters the earth atmosphere. A meteorite is a piece of rock that floats in space. A meteorite is when a meteoroid lands on the earth’s surface as a solid.

What is a chromosphere?

The chromosphere is the second layer of the sun, A thin layer of plasma.

What is the corona?

The corona is the outermost layer of the suns atmosphere.

What are sunspots?

Sunspots are cooler regions on the suns surface. These are only temporary.

What is the core of the sun?

The core of the sun is the central region where nuclear fusion happens.

What is a ‘falling star”?

It is a meteor, a streak of light when a meteoroid burns because of the earth’s atmosphere.

What is terrestrial and Jovian?

Terrestrial planets are rocky and smaller, while jovian planets and gas giants and larger.

Why does the moon has no atmosphere?

The moon has no atmosphere because of its weak gravity. It cannot retain gas molecules, it constantly escapes.