f

PART I: Astronomy with the Human Eye (The Need for Telescopes) Picture of the magazine cover I used as Reference

Picture of the Set-up: The newspaper is set on the kitchen counter and stands thanks to a prop behind it. To mark the different distances I used objects with a flat surface, the

side facing the counter is where the maximal distance is delimited. I didn’t have a ruler or measuring tape so I utilized an online ruler which adapts the centimetric measures to the screen you’re using Text to be read Distance (cm) Size of Print Ratio (R) La Quinzaine 1065 2.7 394.4 littéraire 457 1.2 380.83 Delacroix 320 0.6 533.33 ● ‘ representative’ value of R: 436.19 ○ 394.4 + 380.83 + 533.33 = 1308.56 1308.56 / 3 = 436.1867 Question 1: ● What size of feature would the astronauts be able to see? 917.03 m The ISS orbits at an average altitude of 400 kilometers above the Earth. The value of R is 436.19. Case 2=Distance/R Given: ● Size of Rogers Stadium=200 meters ● R=436.19 ● Distance D from the ISS to Earth's surface ≈ 400 km (400,000 meters) (NASA(1), 2024.) ● Minimum Size: 400,000/436.19 ● Given that, would they be able to pick out Rogers Stadium, in Toronto? No ○ The minimum size of details that astronauts could discern on the ground without aid is approximately 917.03 meters. The Rogers Stadium is about 200 meters across making it smaller than the calculated minimum discernible size by around 717m. Astronauts would not be able to pick out the Rogers Stadium with the unaided eye from the ISS Question 2: Do you think the Great Wall would be observable from the ISS? ● Average width of the Great Wall is about 4-5 meters ● Average height is around 6 to 7 meters (Chinadiscovery) ● The ISS orbits Earth at an altitude of approximately 400 kilometers ● Length of the wall is 21,196km (Britannica)

Using Case 2 from question 1: the minimum size of detail discernible from the ISS is about 917 meters. And while the Great Wall is indeed extremely long, its width and length can only be described as narrow from a celestial perspective. The case study’s minimum size is still much bigger than some of the dimensions of the Great Wall (for context the Wall’s width would need to be around 204 times as large as it is now to make up for it). Therefore suggesting that the wall's both width and height are too small to be discerned from the ISS without any aids. The idea that the Great Wall is visible from space with the naked eye is more of an urban legend. The wall's gray-brown color blends in with the natural landscape, and its relatively narrow width makes it indistinguishable from such a vast distance. Even if it were to be painted a bright color the distance from the ISS would still make it challenging to see. Reports from astronauts (including those from China), have indicated that it's not possible to see the Great Wall from orbit with the unaided eye. This aligns with the previous calculations. Source of Chinese astronaut: https://www.theguardian.com/science/2003/oct/23/thisweekssciencequestions “Yang told Chinese TV when he returned to Earth last week. "I didn't see the Great Wall."” Q uestion 3: How big would a feature on the Moon need to be if we are to discern it from the Earth with the unaided eye? 880.35km ● Distance from Earth to the Moon: 384,000 km. (NASA(2)) ● R value is 436.19 Minimum size= 384,000*1000(convert to meters)/436.19 = 880350.306059 = 880350.306059/1000 = 880.35 km ● Lake Ontario stretches around 311 km from Kingston to Hamilton (Sail Lake Ontario). ○ like we’ve seen with the Great Wall. being long doesn't automatically make it visible from the ISS. It's more about the size and how it stands out against the background. ● For any feature on the Moon to be spotted with just our eyes from Earth it's got to be at least about 880.35 km big in diameter. Thinking about a big red patch the size of Lake Ontario, which is roughly 311 km long doesn't quite cut it.