Question 10(2 points)

Recall the last conical section that I made with a bottomless coffee cup and my cellphone. If a newly discovered comet moves on this type of orbit, and at its closest approach to the Sun was at 0.26 AU on 11th Oct. 2025, it will again approach the same distance to the Sun on:

Question 10 options:

	11th Oct. 2029
	21st Apr. 2027
	Never
	29th Nov. 2025

Question 11(2 points)

What is at the centre of the long-exposure images we discussed in Week 1d Module?

Question 11 options:

	Vega
	Polaris
	Sirius
	Southern Cross

Question 12(2 points)

What would the answer be to the last question, if I teach this course in 15000 years?

Question 12 options:

	Polaris
	Vega
	Southern Cross
	Sirius

Question 13(2 points)

In Week 1d module, when we talked about measuring angles in the sky, I showed a slide with 3 different sky views. The first view showed the moon, and its angular size. The second view showed Big Dipper and how it points to Polaris. Now imagine you are the person observingthe third view(which shows another constellation). For you, the star Polaris:

Question 13 options:

	is at Zenith
	Can be seen in part of the year, depending on the season
	Has an altitude of 7 degrees
	cannot be seen

Question 14(2 points)

Saved

The official start of the Muslim holy month of Ramadan is at the first sighting of the crescent moon, after the New Moon that follows the month Sha'aban.

This sighting happens:

Question 14 options:

	just before sunrise
	just after sunrise
	just before sunset
	just after sunset

Question 15(4 points)

The Sun completes a full 360 degrees along the ecliptic circle on the celestial sphere, once a year (=365.24 days). Based on the course video on Kepler's laws, determineSun's angular speed (in degrees per day) on celestial sphere, when:

Question 15 options:

123	Earth is at the topmost point of its orbit on the slides.
123	Earth is at the leftmost point of its orbit on the slides.
123	Earth is at the rightmost point of its orbit on the slides.
123	Earth is at the bottommost point of its orbit on the slides.

1.	1.02
2.	0.95
3.	0.99

Question 16(3 points)

Find the angular resolution of amystery telescope, for light with wavelength of 1.5 microns.

The aforementionedmystery telescopewas given as an example when we discusseddiffraction limitin the course.

Give your answer in arcseconds, at 5% precision.

Your Answer:

Question 16 options:

Answer

Question 17(2 points)

A Scientific Model must

Question 17 options:

	rely solely on natural causes
	explain the observations as simply as possible
	make testable predictions
	All of the above

Question 18(3 points)

When we discussed the first time that humans managed to measure the size of the Solar System (or distance to planets), I showed an astronomical event that was observed from both Europe and South Africa, at the same time. What event was this, and did it last longer in Europe or South Africa?

Question 18 options:

Question 19(6 points)

In our discussion of extrasolar planets, I gave an example of a star with several planets that were discovered through their transits. If all those planets happen to be transiting at the same time (and do not block each other), what fraction the light from the star will be blocked? Give your answer in percentage, with 2 significant digits.

Question 19 options:

Question 20(4 points)

In our discussion of Weight in Space, we explored three scenarios: a person standing on top of a tall tower jumping forward at three different speeds, which resulted in three distinct orbits. Which orbital shape resulted from the fastest jumping speed for our brave protagonist in these scenarios? Compute this speed in km/s, to 2 significant digits.

(You can ignore air friction, and assume the height of the tower is much shorter than the radius of Earth)