1. What objects Hershel and Shapley, respectively, used to map the Galaxy? What were their results and why did they come up with such different dimensions of our Galaxy?
2. What are the four major parts of our galaxy? Summarize their main properties? What type of orbital motion do the objects exhibit in each part?
3. At the center of our Milky Way Galaxy, there is a supermassive black hole. Infrared observations show that a star that has mass ~ 100 M⦿, orbits around this black hole once every 14.5 years on an elliptical orbit with a semi-major axis a = 920 AU. Estimate the mass of this black hole at the Galactic center.
4. The Sun moves around the Galactic center in a nearly circular orbit with the radius R0 ~ 8 kpc at the orbital velocity v0 ~ 220 km s−1. The total mass of the Galaxy within the Sun’s orbit is MG. The observed Galactic rotation curve shows an orbital velocity of stars v ~ 270 km/s at near the outer boundary of the visible Galactic disk (d ~ 16 kpc from the Galactic center). Calculate the total Galactic mass between the Sun’s orbit and the outer boundary of the Galactic disk in units of MG.
5. The Sun orbits around the Galactic center at the distance of d0 = 8 kpc with a velocity of v0 = 220 km s−1. Assuming that the mass beyond the solar orbit along the Galactic disk is negligible compared to that within the solar orbit, what rotational velocity would be expected for a star orbiting at the distance of d = 16 kpc from the Galactic center?
6. Using Cepheid variables, Edwin Hubble measured the distance to many spiral nebulae, for example he measured the distance ~ 300 kpc for Andromeda Nebula. This marks a historic discovery. What is the astronomical significance of this measurement?
7. You observed a galaxy where you found no current star-forming activity. Would you expect that there are neutron stars in this galaxy? Justify your answer.
8. Explain what dark matter is and how it was discovered in our and other galaxies.
9. What are the three major types of galaxies? Rank them from a) smallest range of sizes to largest range of sizes, b) no new star formation to vigorous star formation, c) bluish to yellow-whitish to reddish, d) mostly population I to mostly population II stars. (You should know what are population I and II type stars.)
Can you please give me guidance to what websites I should look at to answers all of these questions? Thank you.-xoxo
Brainly has a lot of expert feedback, and they respond quite fast. Might be worthwhile trying them.
Brainly.com
Thank you!
Certainly! Here are some reliable websites where you can find information to answer the questions:
1. To find information about Hershel and Shapley's mapping of the Galaxy, their results, and the differences in their dimensions of the Galaxy, you can refer to reputable astronomy and astrophysics websites such as NASA's website (www.nasa.gov) or the European Space Agency's website (www.esa.int).
2. To learn about the four major parts of our galaxy, their main properties, and the type of orbital motion exhibited by objects in each part, you can visit websites such as the National Optical Astronomy Observatory (www.noao.edu) or the University of California, Berkeley's Astronomy Department website (astro.berkeley.edu).
3. To estimate the mass of the black hole at the center of our Milky Way Galaxy based on the given information, you can refer to research papers, scientific journals, or websites such as the Harvard-Smithsonian Center for Astrophysics (www.cfa.harvard.edu) or the Black Hole Initiative at Harvard University (bhi.fas.harvard.edu).
4. To calculate the total Galactic mass between the Sun's orbit and the outer boundary of the Galactic disk in units of MG using the provided data, you can refer to resources such as astrophysics textbooks, research papers, or websites such as the Sloan Digital Sky Survey (www.sdss.org) or the NASA Exoplanet Archive (exoplanetarchive.ipac.caltech.edu).
5. To determine the expected rotational velocity of a star orbiting at a distance of 16 kpc from the Galactic center, based on the given conditions, you can consult textbooks on galactic dynamics or research papers available on platforms like NASA ADS (ui.adsabs.harvard.edu) or arXiv.org.
6. To understand the astronomical significance of Edwin Hubble's measurement of the distance to the Andromeda Nebula and its impact on our understanding of the universe, you can explore resources such as the American Astronomical Society's website (aas.org) or the Hubble Space Telescope's website (hubblesite.org).
7. To determine whether neutron stars would be expected in a galaxy with no current star-forming activity, you can refer to resources such as astrophysical journals, research papers, or websites like the Chandra X-ray Observatory's website (chandra.harvard.edu) or the National Radio Astronomy Observatory (public.nrao.edu).
8. To learn about dark matter and its discovery in our and other galaxies, you can visit websites such as the Dark Energy Survey project's website (www.darkenergysurvey.org) or the Cosmic Microwave Background website maintained by NASA (cmbpol.kek.jp).
9. To understand the three major types of galaxies, their size ranges, star formation activities, and stellar populations, you can refer to resources such as astronomy textbooks, online courses, or websites like the HubbleSite (hubblesite.org) or the National Aeronautics and Space Administration (NASA) website (www.nasa.gov).
Remember to always critically evaluate the sources and choose reputable websites or scientific literature for accurate information. Happy exploring and learning!