1 A Galaxy Revealed Among the great astronomical mysteries x the 1800s were the spiral nebulac, which appeared in telescopes as swirling cloadlike forms, bu whose nature was unknown Four different renderings of one such spiral nebula, designated M5!are shown in Figure 15-5 Figure 15-5A is a drawing from 1845 by William Pursons, the Earl of Rosse, who viewed MSI through what was then the world's larges telescope and sketched what he saw Figure 15-5B is a picture from 1889 by English amaceur astronomer Isaac Roberts, and is perhaps the first-ever photograph of MS1. Figure 13.5C is a 1950 photograph that was taken through the largest -in-the-world telescope of that era, the 200 -inch Hale reflector on Mr. Palomar in Califomia Figure 15-5D was obtained with the Hubble Space Telescope in 2005. Today we know that spiral nebaline like MSI are actually spiral galaxies, vast star systems like our own Milky Way galaxy. 11. Compare the four pictures of MSI. Describe similarities and differences 14. What factors might have led to the paticeable improvements in these images over time?

11. Comparing the four pictures of MSI, we can observe the following similarities and differences:<br /><br />Similarities:<br />- All four images depict the spiral nebula MSI, which appears as a swirling cloud-like form.<br />- The spiral structure is visible in all four images, indicating the presence of a spiral galaxy.<br /><br />Differences:<br />- The earliest image (Figure 15-5A) is a sketch by William Purcass, the Earl of Rosse, in 1845. It is a hand-drawn representation and lacks the level of detail and clarity seen in the later images.<br />- The second image (Figure 15-5B) is a photograph taken by Isaac Roberts in 1899. This is the first-ever photograph of MSI, and it shows a more defined and detailed structure compared to the sketch.<br />- The third image (Figure 15-5C) is a 1950 photograph taken through the 200-inch Hale reflector on Mt. Palomar in California. This image has even better resolution and detail, capturing the spiral arms and the central bulge of the galaxy.<br />- The final image (Figure 15-5D) was obtained with the Hubble Space Telescope in 2005. This image has the highest resolution and clarity, allowing us to see individual stars and other details within the spiral arms.<br /><br />14. The noticeable improvements in the images of MSI over time can be attributed to several factors:<br /><br />- Advancements in telescope technology: As telescopes became larger and more advanced, they were able to gather more light and provide higher-resolution images. This allowed astronomers to capture more detail and clarity in the images of MSI.<br /><br />- Improvements in photographic techniques: The transition from hand-drawn sketches to photographs allowed for more accurate and detailed representations of the spiral nebula. The development of more sensitive and advanced photographic materials also contributed to the improved quality of the images.<br /><br />- Increased observation time: As telescopes became more powerful, astronomers were able to observe MSI for longer periods, allowing them to capture more comprehensive and detailed images.<br /><br />- The use of space-based telescopes: The Hubble Space Telescope, being located above the Earth's atmosphere, was able to provide even higher-resolution images of MSI. The lack of atmospheric distortion and the ability to observe in various wavelengths further enhanced the quality of the images.<br /><br />Overall, the combination of technological advancements, improved observational techniques, and the use of space-based telescopes have led to the remarkable improvements in the images of MSI over time.