Celestial Sphere and Evolution of Astro Practice

most stars and constellations slowly rise in the east, pass overhead, and set in the west

When we watch the nighttime sky here in Utah, we find that…

4 minutes earlier

On an average the stars rise at a different time from the previous night. By how much?

Stars rise and set from east to west

Which of the following is caused by the Earth’s rotation (spin)?

-Moon goes through phases

-Different constellations in the early evening during different months

-Stars rise and set from east to west

-The altitude of the sun increasing during the summer and decreasing in the winter

About half way up the sky from the North horizon

Where is the North Celestial Pole as seen from here in Utah?

Polaris

Which star is closest to the North Celestial Pole currently?

8 pm

You go out at 10pm and see Orion just over the Mountain. One month later you are camping and you want to show Orion. What time should you go out to find it at the same place in the sky?

the celestial equator and the ecliptic

The equinoxes are located at the intersections of the

less than 12 hours

If a star rises in the southeast, how long until it sets in the southwest?

9 am

If a star rises in the NE at 7pm. Which is an appropriate time for when it could set?

Earth's orbit around the sun

We see Orion in Winter at 9pm in our sky, but in the summer I have to go out at 3 am to see it. Why?

Latitude

Declination on the celestial sphere has this role on the Earth’s coordinate system:

circumpolar

These stars are always above the horizon.

circle of animals

Zodiac means ________.

13

How many Zodiac constellations ACTUALLY lie on the ecliptic?

26000 years

Precession takes about ___________ to complete one full cycle.

Obliquity describes the tilt of Earth’s axis while precession describes motion/direction of Earth’s axis

What’s the difference between precession and obliquity?

False

T or F Isaac Newton was the first scientist to use a telescope for astronomical discoveries

False

True or False: Kepler gave us the law of gravitation.

True

True or False: The gravitational pull between two objects is stronger the closer together they are.

It increases

As objects move closer toward each other, what happens to the gravitational pull between them?

The Earth

Most ancient Greeks used a geocentric model. What was at the center of their model

True

T or F: A comet way out by Pluto feels the gravitational pull of the sun.

The same speed in the same direction

According to Newton's laws of motion, if an asteroid is traveling out in space and doesn't feel any gravity (not possible, but let's say it happens) what will happen to it?

Tycho

Significant number of planetary observations

Kepler

determined by matching observations that the planets orbit the sun in ellipses and follow other laws

Copernicus

Founder of the heliocentric model with circular orbits

Galileo

Saw that Venus exhibits phases like the moon among other things

Ptolemy

devised a geocentric model using epicycles to predict location

True

T or F: Galileo is credited with being the first person to look at the night sky with a telescope

True

T or F: Bigger telescopes are able to show fainter objects

Newton

Whose laws of motion made it possible for us to understand the motion of objects in space?

100 times weaker

If Earth were to be moved to a distance of 10 AU from the Sun, how much stronger or weaker would be the Sun’s gravitational force on Earth?

the relative motions of Earth and planet

Retrograde motion of a planet when viewed from Earth is caused by

None of them

Which of the planets can be found by the North Celestial Pole as seen from the Earth? 

True

T or F: The Earth’s precession means that we sometimes may not have a polar star.

Reflecting

Which type of telescope using mirrors?

The location during the sun’s path when it is furthest south in the sky

The Winter Solstice is ….

50%

During one complete year, an observer on the north pole would be able to see what fraction of the overall sky? (this question does take into account the rotation and annual motion of the Earth)

Phases of Venus

Which of the following seen by Galileo was an observable for a heliocentric solar system?

True

T or F: Polaris (the North Star) is up in the sky during the daytime, we just can’t see it.

False

T or F: The Planet Mars stays “in” the same stars during the course of one whole Earth year.

True

T or F: For those who live on the equator, all the stars rise and set. (remember there are no actual stars at the exact locations for the Celestial poles.)

True

T or F: The Celestial Equator separates the Celestial Sphere into a north half and a south half?

as distance increases, gravity decreases at a greater rate

Gravity is determined by an inverse square law with distance. This means essentially that

inertia

A body at rest that stays at rest exhibits the concept of

a body that maintains the same velocity unless forces act on it

Newton's first law is best expressed as

in a straight line in the direction that it was moving when the string broke.

A mass is being moved in a circle by a string. If the string breaks the mass will initially move

False

T or F Mass and weight are the same thing.

F=ma

The Second Law of Motion is best described as

change in velocity

Acceleration is _______ over a period of time.

change in position

Velocity is _______ over a period of time

True

T or F: Little ‘g' is considered the surface gravity acceleration.

in circular motion

Centripetal force applies to a body

True

T or F: A centripetal force on an object moving in a circle always points toward the center of the circle.