Concept explainers
When a “spiral nebula” is observed closer than some of our galaxy, would it be an evidence in favor of Shapley’s argument or Curti’s argument.
Answer to Problem 1CC
Solution:
The closeness of “spiral nebula” as compared to other stars in our galaxy will give evidence that supports Shapley’s argument.
Explanation of Solution
Introduction:
Spiral nebulae: Spiral nebulae are the clouds that are spiral in shape, which were later found to be galaxies themselves. These lie outside the region of the Milky Way.
Explanation:
The astronomical community was divided into two groups on the basis of nature of the spiral nebula. In April 1920 two different ideas were presented in front of the National academy of science in Washington D.C.
On one side there was a scientist named Harley Shapley, who was from the Mount Wilson Observatory. According to Shapley, the size of the spiral nebula was relatively small and the nearby objects scattered around our galaxy.
On the other hand, was Heber D. Curtis from the University of California Lick laboratory, who said that each of these spiral nebulae is a rotating system of stars similar to our galaxy.
Conclusion:
From the above observation, it can be concluded that if the spiral nebula is closer than some of the starts, then it would give evidence in favor of Harley Shapley’s argument.
Want to see more full solutions like this?
Chapter 23 Solutions
Universe
- Would you expect to observe every supernova in our own Galaxy? Why or why not?arrow_forwardWhy do nebulae near hot stars look red? Why do dust clouds near stars usually look blue?arrow_forwardThe best parallaxes obtained with Hipparcos have an accuracy of 0.001 arcsec. If you want to measure the distance to a star with an accuracy of 10%, its parallax must be 10 times larger than the typical error. How far away can you obtain a distance that is accurate to 10% with Hipparcos data? The disk of our Galaxy is 100,000 light-years in diameter. What fraction of the diameter of the Galaxy’s disk is the distance for which we can measure accurate parallaxes?arrow_forward
- Consider the following five kinds of objects: open cluster, giant molecular cloud, globular cluster, group of O and B stars, and planetary nebulae. A. Which occur only in spiral arms? B. Which occur only in the parts of the Galaxy other than the spiral arms? C. Which are thought to be very young? D. Which are thought to be very old? E. Which have the hottest stars?arrow_forwardWhy does star formation occur primarily in the disk of the Galaxy?arrow_forwardHow can the Crab Nebula shine with the energy of something like 100,000 Suns when the star that formed the nebula exploded almost 1000 years ago? Who “pays the bills” for much of the radiation we see coming from the nebula?arrow_forward
- You can use the equation in Exercise 22.34 to estimate the approximate ages of the clusters in Figure 22.10, Figure 22.12, and Figure 22.13. Use the information in the figures to determine the luminosity of the most massive star still on the main sequence. Now use the data in Table 18.3 to estimate the mass of this star. Then calculate the age of the cluster. This method is similar to the procedure used by astronomers to obtain the ages of clusters, except that they use actual data and model calculations rather than simply making estimates from a drawing. How do your ages compare with the ages in the text? Figure 22.10 NGC 2264 HR Diagram. Compare this HR diagram to that in Figure 22.8; although the points scatter a bit more here, the theoretical and observational diagrams are remarkably, and satisfyingly, similar. Figure 22.12 Cluster M41. (a) Cluster M41 is older than NGC 2264 (see Figure 22.10) and contains several red giants. Some of its more massive stars are no longer close to the zero-age main sequence (red line). (b) This ground-based photograph shows the open cluster M41. Note that it contains several orange-color stars. These are stars that have exhausted hydrogen in their centers, and have swelled up to become red giants. (credit b: modification of work by NOAO/AURA/NSF) Figure 22.13 HR Diagram for an Older Cluster. We see the HR diagram for a hypothetical older cluster at an age of 4.24 billion years. Note that most of the stars on the upper part of the main sequence have turned off toward the red-giant region. And the most massive stars in the cluster have already died and are no longer on the diagram. Characteristics of Main-Sequence Starsarrow_forwardAt the average density of a star-forming molecular cloud, about 900 atoms per cm3, determine how large a sphere you would need to encompass mass equal to that of the Sun? Enter the radius of this sphere in light-years. (HINTS: 900 atoms per cm3 corresponds to a density of 1.51×10-18kg/m^3; the mass of the Sun is 2×1030kg) (The volume of a sphere is 4/3 * π * R3) (my previous answer of 6.812 X 1015 was incorrect)arrow_forwardusing the center-of-mass equations or the Carter of Mass Calculator (under Binary-Star Basics, abova), you will investigate a specific binary star system. Assume that Star 1 has m, 3.2 solar masses, Star 2 has m,-0.9 solar masses, and the total separation of the two (R) is 34 All (One AU is Earth's average distance from the Sun) (2) What is the distance, d. (In Au) from Star 1 to the center of mass? AU (b) What is the distance, dy On Au) from Star 2 to the center of mass AU ( what is the ratio of d, tod?arrow_forward
- AstronomyPhysicsISBN:9781938168284Author:Andrew Fraknoi; David Morrison; Sidney C. WolffPublisher:OpenStaxStars and Galaxies (MindTap Course List)PhysicsISBN:9781337399944Author:Michael A. SeedsPublisher:Cengage Learning
- Foundations of Astronomy (MindTap Course List)PhysicsISBN:9781337399920Author:Michael A. Seeds, Dana BackmanPublisher:Cengage Learning