Astronomy lecture tutorials/ranking task answers

What is the parallax angle for the nearby star exhibiting parallax from question 9?

1/8 arcsecond

To make a scale model of the Earth-Moon orbital system you not only need to pick appropriately sized objects to represent Earth and the Moon, you also need to place them the correctly scaled distance apart. Lets say you use a 1 foot basketball and a 3 inch orange as your Earth and Moon. About how far apart must they be placed to present accurate scale model of the Earth-Moon orbital system?

30 feet.

If we used a basketball to represent the Sun and a ping pong ball to represent Earth, and separated them by the distance in quetion 6, would we have an accurate scale model of Sun-Earth system?

No Ping pong ball used for earth is too large.

What is the angular separation between he end points that you marked in figure 1 for the nearby star exhibiting parallax?

The moving star distance is half the A-B star distance.

Compar answer for bar house angle from Question 1 and the Moon-star angle from question 2. Are they the same?

Yes they are

Which of the following pairs of objects would make a good scale model of Earth and the Moon?

a basketball and a baseball (or softball)

The star Lee ha an apparent magnitude of 0.1 and is located 250 parsecs away from Earth. Which of the following is most likely the absolute magnitude for Lee?

-6.9

If you were to use 1 foot basketball to represent Sun, how far would it have to be from Earth to be accurate scale model?

110 feet

For a star with parallax angle of 1/2 an arcsecond, what is its distance from us?

2 parsecs

Approx. how many times could the Moon's orbital diameter fit between Earth and the Sun?

220 Moons would fit between the Sun and the Earth

For a star with a parallax angle of 1/4 an arcsecond, what is its distance from us?

4 parsecs

How many moons would fit across the diameter of the Sun?

440 moons fit across the sun

What is the distance from us to the nearby star exhibiting parallax in the drawing from figure 2?

8 parsecs

What is the angle between you, the house, and the barn?

90 degrees

You see the Moon on the horizon just above the barn in the east and also a bright star directly overhead. What is the angle between you, the Moon, and the overhead star?

90 degrees

Student 1: If the distance to the star is more than 1 parsec, then the parallax angle must be more than 1 arc second. So a star that is many parsecs away will have large parallax angle Student 2: if we drew a diagram for a star that was much more than 1 parsec away from us, the triangle in the diagram would be pointer than the one we just drew.

Agree with student 2 because as the parallax angle is smaller the star's distance is greater.

tells us how bright an object will appear from earth.

Apparent magnitude

Can any combinations of the following items be used to make an accurate scale model of Earth and the Sun?

Baseball for sun, grain of sand for Earth

Is a parsec a unit of length or a unit of angle?

It is a unit of length

Describe how star A would appear to move among the distant stars as Earth orbits the Sun counterclockwise from January one year, through July,to January the following year.

It would move in a straight line between the two X's with a motion in time similar to a swinging pendulum

Do the angles from above tell you anything about the actual distance between the barn and house or the Moon and star?

No. Such angular measure on celestial sphere tells us nothing about the actual distance between the object because there is no accounting for the distance between each object and earth.

Which star, the closer one (A) or the farther one (B) has the large parallax angle?

Star A

Student 1: I think a star with an apparent magnitude number of -2.0 would look brighter than a star with an apparent magnitude number of +1.0. Student 2: I disagree. You don't understand the number of scale for apparent and absolute magnitude. The bigger the number the brighter the star. So the +1.0 star would look brighter than the -2.0 star.

Student 1 has it right. Negative magnitudes represent greater apparent brightness.

How many times bigger is separation between star a and b compared to distance between end points of line showing range of motion for star exhibiting parallax?

The A-B star distance is is twice as big as the moving star distance.

Does this mean two Sun's place side by side would fit inside Moon's orbit around Earth, or that two moon orbits placed side by side would fit across sun?

This means two Moons would fit side by side inside the Sun.

What is the angular separation between stars c and d in arc seconds?

Twice times a half is 1 arcsecond

The full moon has an apparent magnitude of -12.6, and when Mars is at its brightest in the night sky, the apparent magnitude is +2.0

a. Mars b. Full moon c. +3 mag object

tells us about object's actual brightness.

absolute magnitude.

If star c appears to move back and forth by a greater amount than star d, which star do you think is closer to you?

star c