21st Century Astronomy
6th Edition
ISBN: 9780393428063
Author: Kay
Publisher: NORTON
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Chapter 15, Problem 16QP
To determine
Reason why gas does not block a visible light view of galactic center.
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Chapter 15 Solutions
21st Century Astronomy
Ch. 15.1 - Prob. 15.1CYUCh. 15.2 - Prob. 15.2CYUCh. 15.3 - Prob. 15.3CYUCh. 15.4 - Prob. 15.4CYUCh. 15 - Prob. 1QPCh. 15 - Prob. 2QPCh. 15 - Prob. 3QPCh. 15 - Prob. 4QPCh. 15 - Prob. 5QPCh. 15 - Prob. 6QP
Ch. 15 - Prob. 7QPCh. 15 - Prob. 8QPCh. 15 - Prob. 9QPCh. 15 - Prob. 10QPCh. 15 - Prob. 11QPCh. 15 - Prob. 12QPCh. 15 - Prob. 13QPCh. 15 - Prob. 14QPCh. 15 - Prob. 15QPCh. 15 - Prob. 16QPCh. 15 - Prob. 17QPCh. 15 - Prob. 18QPCh. 15 - Prob. 19QPCh. 15 - Prob. 20QPCh. 15 - Prob. 21QPCh. 15 - Prob. 22QPCh. 15 - Prob. 23QPCh. 15 - Prob. 24QPCh. 15 - Prob. 25QPCh. 15 - Prob. 26QPCh. 15 - Prob. 27QPCh. 15 - Prob. 28QPCh. 15 - Prob. 29QPCh. 15 - Prob. 30QPCh. 15 - Prob. 31QPCh. 15 - Prob. 32QPCh. 15 - Prob. 33QPCh. 15 - Prob. 35QPCh. 15 - Prob. 36QPCh. 15 - Prob. 37QPCh. 15 - Prob. 38QPCh. 15 - Prob. 39QPCh. 15 - Prob. 40QPCh. 15 - Prob. 41QPCh. 15 - Prob. 42QPCh. 15 - Prob. 43QPCh. 15 - Prob. 44QPCh. 15 - Prob. 45QP
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- 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_forwardThe mass of the interstellar medium is determined by a balance between sources (which add mass) and sinks (which remove it). Make a table listing the major sources and sinks, and briefly explain each one.arrow_forwardIf the Sun were a member of the cluster NGC 2264, would it be on the main sequence yet? Why or why not?arrow_forward
- How would the density inside a cold cloud (T=10K) compare with the density of the ultra-hot interstellar gas (T=106K) if they were in pressure equilibrium? (It takes a large cloud to be able to shield its interior from heating so that it can be at such a low temperature.) (Hint: In pressure equilibrium, the two regions must have nT equal, where n is the number of particles per unit volume and T is the temperature.) Which region do you think is more suitable for the creation of new stars? Why?arrow_forwardA molecular cloud is about 1000 times denser than the average of the interstellar medium. Let’s compare this difference in densities to something more familiar. Air has a density of about 1 kg/m3, so something 1000 times denser than air would have a density of about 1000 kg/m3. How does this compare to the typical density of water? Of granite? (You can find figures for these densities on the internet.) Is the density difference between a molecular cloud and the interstellar medium larger or smaller than the density difference between air and water or granite?arrow_forwardDescribe the characteristics of the various kinds of interstellar gas (HII regions, neutral hydrogen clouds, ultra-hot gas clouds, and molecular clouds).arrow_forward
- How are giant molecular clouds (GMCs), the loci of most star formation, themselves formed out of diffuse interstellar gas? What processes determine the distribution of physical conditions within star-forming regions, and why does star formation occur in only a small fraction of the available gas? How is the rate at which stars form determined by the properties of the natal GMC or, on a larger scale, of the interstellar medium (ISM) in a galaxy? What determines the mass distribution of forming stars, the initial mass function (IMF)? Most stars form in clusters (Lada & Lada 2003); how do stars form in such a dense environment and in the presence of enormous radiative and mechanical feedback from other YSOs?arrow_forwardThe very first “image" of a black hole, at the centre of galaxy M87, was recently taken by the Event Horizon Telescope (EHT). More accurately, EHT imaged radio emission from the disc of gas that orbits the black hole with a lack of emission from the centre being attributed to the black hole. This image was only possible because EHT is not a single radio telescope, but is in fact a network of telescopes from around the world that take advantage of something known as interferometry. Interferometry is a method for combining the light from multiple telescopes, which results in an image that could have been taken by a telescope that has a diameter equal to the distance between the telescopes referred to as the "“baseline"-rather than the size of each individual telescope. EHT in particular combines observations from several Very Long Baseline Interferometry (VLBI) stations in order to achieve a high angular resolution. (a) Given that the "baseline" of EHT is effectively the diameter of the…arrow_forwardThe very first "image" of a black hole, at the centre of galaxy M87, was recently taken by the Event Horizon Telescope (EHT). More accurately, EHT imaged radio emission from the disc of gas that orbits the black hole with a lack of emission from the centre being attributed to the black hole. This image was only possible because EHT is not a single radio telescope, but is in fact a network of telescopes from around the world that take advantage of something known as interferometry. Interferometry is a method for combining the light from multiple telescopes, which results in an image that could have been taken by a telescope that has a diameter equal to the distance between the telescopes-referred to as the “baseline"-rather than the size of each individual telescope. EHT in particular combines observations from several Very Long Baseline Interferometry (VLBI) stations in order to achieve a high angular resolution. (a) Given that the "baseline" of EHT is effectively the diameter of the…arrow_forward
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