Space Science Learning Experience 1

Astronomy is what two types of sciences?

Historical science and observational science

Light-year

The distance light travels in one year / 5.8 × 10¹² miles

How does nature reveal itself?

observations, experiments, models, and testing

What are the most common elements in the universe?

hydrogen and helium

Aristotle’s evidence for the Earth being round?

The shadow on the moon is always round, and not everyone sees the same stars overhead.

parallax

shift in direction of an object due to the observer moving

stellar parallax

shift in apparent direction of a star due to Earth’s orbit

What did Eratothenes discover?

He calculated the Earth’s circumference and discovered that the Earth is round by using 2 wells in Alexandria and Syene, and observing the shadows (or lack of shadows)

What did Hipparchus do?

He measured the position of objects in the sky and calculated the brightest and dimmest stars, as well as developed a system with celestial coordinates. He also hypothesized precession.

precession

The slight “wobble” of the Earth; the slow circular motion of Earth’s axis rotation

What is precession caused by?

The gravitational pole of the moon and sun

How many years does it take for the North Star to change due to precession?

Approximately 26,000 years

What did Ptolemy discover?

He created a method that predicted the positions of the sun, moon, and planets in the sky

What is the Epicycle/Ptolemaic Theory?

“wheels within wheels” or “circles within circles”

retrograde motion

the apparent motion when planets seem to go backwards, and then speed up

What were the two major flaws that set Ptolemy back?

The belief that the Earth is the most important, and thus in the center, and that everything is in a perfect circle

zenith

the point directly above your head when you look up and the sky looks like a dome

astrology

the thought that the positions of the bodies among the stars are thought to hold the key to understanding life

What did Nicolaus Copernicus discover?

He developed a sun centered (heliocentric) model of the solar system, and a picture of where all the planets belong.

What did Galileo Galilei discover?

He studied motion and the action of forces on bodies, and created the first telescope

mean solar day

interval when the sun is at the celestial median from one day to the next due to Earth’s rotation; takes 4 minutes longer to return to the median

sideral

interval when the stars are at the celestial median from one day to the next (star time)

What did Aristotle believe?

that the universe was symmetrical, spherical, and finite with the earth at the center

How fast does light travel?

9.46 × 10¹² kilometers per second

How many planets are currently in our solar system?

8

The smallest piece of an element that still has all the properties of the element is called?

an atom

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

the earth’s axis

On the celestial sphere, halfway between the celestial pole lies what?

celestial equator

The star that is currently closest to the North Celestial Pole is what?

Polaris

Within a constellation, a smaller, recognizable pattern of stars is often called what?

an asterism

Astronomers divide the whole sky into 88 sections called what?

constellations

What are the steps of the scientific method?

Define the problem, gather data, hypothesis, test the hypothesis, retest, conclusions

How many tests does it take to prove a hypothesis false?

1 or 2

How many tests does it take to prove a hypothesis true?

infinite

What is the order of the solar system?

Sun, Mercury, Venus, Earth, Mars, asteroid belt, Jupiter, Saturn, Uranus, Neptune

speed of light

c = 3×10⁸ m/s = 300,000 km/s

age of the Earth

4.5 billion years

age of the universe

13.8 billion years

Structure of the universe / smallest to biggest

atoms, molecules, meteors, comets, planets, sun, solar system, Milky Way galaxy, clusters of galaxies, universe

Which direction do planets travel when looking at the solar system from above?

counterclockwise

Which direction do the sun, moon, and planets travel from earth?

Rise in the east, set in the west - move eastward in our sky

right ascension

longitude of the sky (west and east), counted in hours/minutes/seconds

declination

how far above or below the celestial equator (north and south), measured in degrees

If you are standing at the equator, where is Polaris?

the northern horizon

If you are standing at the North Pole, where is Polaris?

directly overhead at the zenith

altitude

angle height above the horizon

azimuth

compass direction is the left/right angular measure with respect to the horizon (North = 0 or 360; East = 90; South = 180; West = 270)

What is the angular size of the sun and moon from earth?

½ degree

How quickly does the earth rotate?

¼ degree per minute, 15 degrees per hour

How many degrees does earth move around the sun per day/that the sun seems to move in our sky?

1 degree

The same side of the moon always faces the earth

True

Pythagoras

used mathematics to describe natural phenomena, proposed earth is spherical and revolved around a distant center, studied phases of the moon, lunar eclipses (saw the shadow on the moon was curved)

Aristotle

proposed the earth was spherical, believed the universe was symmetrical, spherical, and finite with earth at the center, the circle was the perfect shape

Aristarchus

first proposed heliocentrism (wasn't taken seriously), estimated size of the moon, estimated earth-moon distance using mathematics/lunar eclipses

Copernicus

founded the heliocentric model of the solar system, explained the position of planets around the sun

Hipparchus

magnitudes of the stars, precession

Galileo

used a telescope to discover the phases of Venus and Jupiter’s moons; provided compelling evidence for the heliocentric model

What causes seasons?

The way the Earth tilts on its axis; causes light to hit more directly and heat more effectively, and effects the amount of daylight

What phase of the moon is this?

waning crescent

What phase of the moon is this?

waxing crescent

What phase of the moon is this?

waning gibbous

What phase of the moon is this?

waxing gibbous

What phase of the moon is this?

first quarter

What phase of the moon is this?

third/last quarter

synodic period

29.5 days, new moon to new moon

lunar sidereal period

27.3 days, period for the moon to make a complete orbit around earth

aphelion

the point when the earth is farthest away from the sun (94.5 million miles, July 4th)

perihelion

the point when the earth is closest to the sun (91.4 million miles, January 3)

perigee

when the moon is closest from the earth

apogee

when the moon is farthest from the earth