StudentShare
Search

# U08a1 Galaxies Review - Coursework Example

Summary
4. How can we use orbital properties to learn about the mass of the galaxy? What have we learned? If we know a star’s orbital period and orbital radius, we can use Newton’s version of Kepler’s third law to determine the mass of the galaxy, with a minor warning: We get only the mass of the galaxy within the orbit of the star we examine…

## Extract of sample "U08a1 Galaxies Review"

Download file to see previous pages The gravitational influence of mass contained within an orbit of a particular size determines the speed (and therefore period) of that orbit. So by measuring the period and size of the orbit, we can determine the mass inside the orbit. This is one method you can use to determine the mass of Jupiter (by looking at the orbits of its moons). Mathematically, the expression for the mass enclosed within an orbit of radius r is M = v2r/G, where G is Newton's gravitational constant and v is the orbital speed of a star at distance r. This concept works equally well for the orbits of stars and gas within spiral galaxies. By looking at the mass inside the orbit of stars or gas at different distances from the center of the galaxy, the mass of a galaxy as a function of radial distance from the center can be obtained from the rotation curve of the galaxy. 7. What are cosmic rays, and where are they thought to come from? Cosmic Rays are extremely high energy charged particles (usually protons) that travel the Universe at nearly the speed of light. Most galactic cosmic rays are probably accelerated in the blast waves of supernova remnants. This doesn't mean that the supernova explosion itself gets the particles up to these speeds. The remnants of the explosions, expanding clouds of gas and magnetic field, can last for thousands of years, and this is where cosmic rays are accelerated. Bouncing back and forth in the magnetic field of the remnant randomly lets some of the particles gain energy, and become cosmic rays. Eventually they build up enough speed that the remnant can no longer contain them, and they escape into the Galaxy. Because the cosmic rays eventually escape the supernova remnant, they can only be accelerated up to a certain maximum energy, which depends upon the size of the acceleration region and the magnetic field strength. 11. How do we know that spiral arms do not rotate like giant pinwheels? What makes spiral arms bright? Spiral arms are regions of stars that extend from the center of spiral and barred spiral galaxies. These long, thin regions resemble a spiral and thus give spiral galaxies their name. Either way, spiral arms contain a great many young, blue stars (due to the high mass density and the high rate of star formation), which make the arms so remarkable. We know that the spiral arms cannot rotate like pinwheels around the center of the galaxy because the inner stars would finish several orbits while the outer stars complete one. This would wind the spiral pattern up, which we do not see. The arms appear bright because of the enhanced star formation in them. The bright, bluer stars in particular make the arms bright since these stars do not live long and so die before spreading far from the arm in which they formed. Therefore spiral arms are bright because they contain many short-lived blue stars that shine for only a few million years. 21. The carbon in my diamond ring was once part of an interstellar dust grain. The carbon in my diamond ring was once part of an interstellar dust grain. This statement is sensible. Much of the carbon in the interstellar medium is in the form of dust grains, so the carbon in the interstellar cloud out of which the Earth formed must also have been largely in the form of dust grains. 36. We measure the mass of the black hole at the galactic center from (a) the orbits of stars in the galactic cente ...Download file to see next pagesRead More
Cite this document
• APA
• MLA
• CHICAGO
(“U08a1 Galaxies Review Coursework Example | Topics and Well Written Essays - 750 words”, n.d.)
(U08a1 Galaxies Review Coursework Example | Topics and Well Written Essays - 750 Words)
https://studentshare.org/finance-accounting/1424445-u08a1-galaxies-review.
“U08a1 Galaxies Review Coursework Example | Topics and Well Written Essays - 750 Words”, n.d. https://studentshare.org/finance-accounting/1424445-u08a1-galaxies-review.
Click to create a comment or rate a document

## CHECK THESE SAMPLES OF U08a1 Galaxies Review

### The Role of Black Holes in the centers of Galaxies

...? The Role of Black Holes in the Centers of Galaxies A black hole is an area in space where “the gravity is so strong that nothing – not even light – can escape it” (Lovgren, 2005). Basically, there are two types of black holes – one type is the remnant of massive stars that have already collapsed and may occur in millions in most galaxies. These are known as stellar mass black holes. The other type of black holes, and the one that we are concerned more about, is the type which is found in the centers of galaxies, which are otherwise known as “supermassive black holes” (Lovgren, 2005). These supermassive black holes have a particular role or roles which may be hypothetical at this point but which can be speculated through careful... ...
4 Pages(1000 words)Essay

### U09a1 Universe Review

...Define dark matter and dark energy, and clearly distinguish between them. What types of observations have led scientists to propose the existenceof each of these unseen influences? Dark energy is a hypothetical form of energy that permeates space and exerts a negative pressure, which would have gravitational effects to account for the differences between the theoretical and observational results of gravitational effects on visible matter. Dark energy is not directly observed, but rather inferred from observations of gravitational interactions between astronomical objects, along with dark matter. Dark matter must exist to account for the gravity that holds galaxies together. Dark matter is also responsible for amplifying...
3 Pages(750 words)Coursework

### Ebay Case Analysis

3 Pages(750 words)Case Study

### Review

...Review of Articles An article by Miner (1990) sets out an evolutionary model that works on the internal structure of the organization throughselective retention of jobs, which can be carried out in conjunction with other structural changes initiated at the executive levels. This model of evolutionary change is based upon refining the internal structure of activities of the organization over a period of time. In the process of structural evolution of these internal processes and activities, the evolutionary process must provide for replication of activities over time, variations in these activities as well as mechanisms geared towards the elimination of some activities. The organizational model provided by Miner also provides... of Articles...
2 Pages(500 words)Essay

### U08a1 Project

...Health Care Introduction: This paper examines the issues regarding lowered care of record of injuries occurred for the employees of the Tufts Medical Center. The organization deal with providing total health care and is a well known and highly reputed medical center ranking among the top five medical institutions of its kind in the United States. This Boston based health care center “offer outstanding patient care to both adults and children, teach generations of future physicians the most advanced medical science and break new ground with ongoing, innovative research.” (Welcome to tufts medical centre, 2010, para.1). Research Issue: However, there is a major concern regarding the performance of Tufts Medical Center... Care Introduction:...
2 Pages(500 words)Essay

### Review

...28 September Review: Commendations: This paper is basically based on contemplating the concise yet informative report based on Intraoperative Magnetic Resonance Imaging (IMRI) which has rapidly become the highly preferred modality for musculoskeletal and neurological imaging in clinical practice since its introduction. The report is largely centered on highlighting the majorly beneficial IMRI systems available in the market and based on their specialties and disadvantages, which of them are most suitable to be incorporated in the department by the physicians. While briefly comparing the modality of IMRI with CT and ultrasound to identify that IMRI presents no limitations when it comes to neurological imaging, the report...
2 Pages(500 words)Research Paper

### Review

...In his article, The Rising Seas, David Schneider gives a thorough overview of the current science supporting or refuting the thought that seal level rise is endangering coastal areas around the world. The article looks at disasters in the recent past where seawalls were topped and thousand of people died. The question that the article attempts to answer is how likely is this to happen again and again in the future? The first section is a discussion of the possible causes of seal level rise. Historical and geologic records indicate that sea level rises and falls continually when measured on a geologic time scale. Causes of this rising and falling include the thermal expansion of water as it is heated by the atmosphere... his article, The...
2 Pages(500 words)Essay

### HAVE taken an online course

2 Pages(500 words)Essay

### Peer review ( critical review)

...Romantic Relationships: Article review This paper seeks to review the article for quality writing and quality science in its arguments. This review will be done through reviewing the arguments in the article to ascertain the manner in which it is written and how the arguments are delivered. Whether there is a catching assertions in the article with facts about the subject will lead to inference of quality science and writing. According to the article, there is inadequate research concerning the development of romantic relationships among young adults and adolescents. This leads to insufficient mastery of the development. This is scientific and proven according to the...
2 Pages(500 words)Essay

### Edwin Hubble - Discovering Galaxies

...﻿Edwin Hubble: Understanding the Galaxies Introduction - Brief Biography Edwin Hubble was born on November 20, 1889 in Missouri, though a lot of his childhood was spent in Illinois. Although he was a good student, Hubble was known more for his athletic abilities than his intelligence. He got good grades while he was in school, though he focused more on his athletic skills, such as track and field and amateur boxing. However, while he attended college at the University of Chicago, he focused on mathematics and astronomy, eventually getting a bachelor of science. He later changed his major to Spanish; he used both his Spanish and science majors to teach at a high school in Indiana. It was in 1917 when Hubble had received his Ph.D... . in...
7 Pages(1750 words)Research Paper