The interpretation is that gravity bends spacetime and that light follows the curvature of space.

Size: px
Start display at page:

Download "The interpretation is that gravity bends spacetime and that light follows the curvature of space."

Transcription

1 7/8 General Theory of Relativity GR Two Postulates of the General Theory of Relativity: 1. The laws of physics are the same in all frames of reference. 2. The principle of equivalence. Three statements of the principle of equivalence: 1. The inertial mass (the one that appears in Newton s second law, F = ma) is the same as the gravitational mass (the one that appears in Newton s law of gravity). 2. No experiment can be done in a closed elevator that will distinguish between being in free fall in a gravitational field or moving with constant velocity in gravity-free space. 3. No experiment can be done in a closed elevator that will distinguish between being at rest in a gravitational field or having a uniform acceleration in gravity-free spece. Consequences of the principle of equivalence (#3) 1. Gravity is a manifestation of the curvature of space. Follow the path of a light pulse in an elevator accelerating in gravity-free space. The dashed line in the top figure shows the path of the pulse as observed by an observer who remains at rest outside the elevator. Each different color rectangle represents the position of the elevator at the given time. The x s represent the locations of the pulses at each given time. The bottom figure shows the path of the pulse as seen by an observer inside the elevator. This observer sees that the pulse falls from the upper left corner of the elevator to the lower right corner. By the principle of equivalence, the same thing must happen in a elevator at rest here on Earth. (Note that we don t see this effect because of the large value of the speed of light. It travels so fast that it doesn t fall a measurable distance in the Earth s weak gravity.) We see that gravity has an effect on light bends the path of the light. The interpretation is that gravity bends spacetime and that light follows the curvature of space. Einstein showed that it is the presence of matter and energy in space that causes spacetime to curve.

2 Einstein s equations are equations for the metric of spacetime. Einstein s Field Equations schematically: Curvature = mass and energy Consider the Pythagorean theorem: Not true in this form on a curved surface. On a curved surface, we have this: The g s are called the metric of the space. The two middle ones are always the same and one can always choose a frame in which they are zero. Einstein s field equations are equations for the metric once we have the metric, we can predict the paths of particles and light through the space. Analogies: 1. Imagine a surgical rubber sheet stretched over a wooden frame. Place a large ball bearing on the sheet, and it will stretch the sheet. A second small ball bearing placed on the sheet next to the first ball bearing will roll toward it as if there were a force gravity! between the two. 2. Consider two bodies traveling with constant speed along two lines of longitude, starting at the equator and heading toward the north pole. As they travel, we see them move closer together because the two lines of longitude intersect at the north pole. From our vantage point in three dimensions, we easily see this to be the case. But a two-dimensional observer on the surface of the sphere won t be aware of the third dimension and will interpret this moving together of the two bodies as a force gravity! between the two. GR is based on the idea that gravitational fields and accelerations are equivalent Principle of Equivalence. If we do an experiment in an accelerating spaceship we will get same results as if we did the experiment sitting at rest in a gravitational field say, at the Earth s surface.

3 Another result of GR time runs slow in a gravitational field. Put John at the bottom of the spaceship and Marsha at the top. John and Marsha both have clocks. At time zero on both clocks, two things happen the spaceship begins to accelerate and John sends a pulse of light toward Marsha. The light pulse moves toward Marsha and eventually reaches her. She sees this as the first tick on John s clock. A time 1 second on John s clock, he sends a second pulse. Since Marsha is now moving away at some speed, it will take longer for this second pulse to reach Marsha than it did for the first pulse to reach Marsha. Marsha measures the time between pulses to be greater than 1 second, that is, greater than the time that John measures. Marsha concludes that John s clock is ticking more slowly than once a second. His clock runs slow. The same thing must happen for an experiment done at rest on Earth. GR has been tested in a number of different ways and has always met predictions. 1. Bending of starlight near the edge of the Sun during and eclipse is correctly predicted by GR. 2. Due to time dilation, GR predicts that laser light should drop in frequency as it travels from the basement to the attic of a building. The experiment agreed with the predictions of GR. 3. GR correctly accounts for a 43 seconds of arc per century precession of Mercury s orbit. 4. GR correctly accounts for a degrees per year precession in a binary neutron star system. 5. There are some competing theories to GR so called scaler/tensor theories. Predictions about the characteristics of binary systems in which on object is much more massive that the other are different in GR and these theories. Recently, a binary system containing a neutron star and a white dwarf where the ratio of the masses is about 12 were measured, and the results predicted by GR agreed with these observational results. GR and Black Holes: If we viewed the contraction of a black hole, we would see the contraction come to a standstill as

4 gravity became strong enough at its surface to bring time to a stop. The point at which this occurs is called the Schwartzchild radius or event horizon. Called the event horizon because at this point the escape speed is equal to the speed of light if light cannot escape, nothing can. We can calculate the Scwartzchild radius of a black hole A black hole with the mass of the Sun would have a radius of 3 km, so we can write where M is the mass of the black hole in solar masses. GR gives us some idea about what goes on inside a black hole. Inside the black, the contraction continues. GR predicts it will shrink to a singularity mathematical point of infinite density. Quantum Mechanics will probably prevent that from happening, but we don t understand the physics yet so we can t be sure. It turns out that an isolated black hole radiates it gets smaller it evaporates Hawking Radiation If a virtual particle-antiparticle pair were to be created near the event horizon of a black hole, one could escape while the other is trapped inside the hole. The one that escapes is the radiation the one that is trapped enters a negative energy state and reduces the mass of the hole. Except for pulsars black holes don t make pulsars all the methods used for detecting neutron stars can be used to detect black holes: 1. Close binary x ray spectrum is different for a black hole because once the matter enters the event horizon, the x rays are cut off. Doesn t happen for a neutrons star. 2. If a dark companion in a binary system is found to have a mass in the black hole range, it must be a black hole. 3. A black hole produces a much larger brightening and much longer brightening in gravitational lensing than does a neutron star. Chapter 11 Galaxies

5 Our own Galaxy Milky Way Galaxy MW Structure First attempt was counting stars out from the Sun. INCORRECT conclusion Disk shape with Sun at the center. Incorrect because gas and dust blocks our view after a certain distance. Harlow Shapely first astronomer to deduce the location of the center of the Galaxy. He noted that globular star cluster orbit about a point in the constellation Sagittarius. This point, about 30,000 ly from the Sun is the center of the Galaxy. We can now map the MW: 1. IR observations tell us where the dust in the Galaxy is. 2. Radio observations tell us where the hydrogen gas (H) is in the Galaxy. Uses the 21-cm emission from hydrogen. Electron has two spin states in the magnetic field of the proton. When aligned, the electron has lower energy than when opposite. When spin flips, a 21- cm photon is emitted. Structure of MW: 1. It has a basic disk shape with a diameter of 100,000 ly. 2. Center has a bulge about 10,000 ly thick. 3. Away from the bulge, thickness is about 1000 ly. 4. Looking down on the MW we see spiral arms coming out from the center much like a pinwheel. 5. It does have a bar-like structure through its nuclear bulge. 6. Gas and dust in the disk is about 500 ly across. What we find in the spiral arms: 1. Almost all the gas and dust in the Galaxy resided in the spiral arms. 2. Sun is about in the spiral arm about 2/3 of the way from the center of the Galaxy. 3. All star formation in the spiral arms. 4. All the young stars.

6 5. All open clusters. 6. No globular clusters. 7. There are some old stars in the spiral arms. What do we find in the nuclear bulge? 1. Almost no gas and dust. 2. No star formation. 3. Only old stars. These parts are the visible parts there is a non visible part called the halo of the Galaxy. Note: The halo of the Galaxy is spherical; it is not a ring. What we find in the halo: 1. Globular star clusters. 2. We have found that, using Newton s law of gravity, the visible matter in the Galaxy does not account for the motion of the visible matter in the Galaxy. Thus, either there is matter out there that is not visible (that is, not detectable) except by its gravitational effect, or Newton s law of gravity and GR are not correct or Newton s second law is not correct. MOND Modification Of Newtonian Dynamics 3. We will take the undetectable matter perspective dark matter. 4. At this point, we don t know what dark matter is. 5. However, apparently dark matter accounts for 90% of the matter in the universe! 6. Dark matter can only be detected gravitationally. Note: the halo of the Galaxy might be 5 times the size of the visible part of the Galaxy. What is the mass of the MW? Use Kepler s third law! Apply it to the orbital parameters of the Sun Note that this will only give us the mass of that part of the MW closer to its center than the Sun is. Time for the Sun to complete one orbit about the center of the MW is 250 million years. Distance from of the Sun from the center of the MW is 30,000 ly or about 8500 pc or AU.

7 Note that value is actually more like due to the fact that there is a lot of matter farther from the center of the MW than the Sun. The Nucleus of the MW its center 1. Can t see the nucleus in visible light too much stuff in the way. 2. Can observe radio waves from the nucleus see a strong radio source there Sagittarius A* or Sgr A*. 3. IR observations show stars to be tightly packed near the center. 4. Distances between stars about 1000 AU not 100,000 AU like out here in the disk. 5. We see a ring of gas that extends from about 6 pc from the center to 25 pc from the center. 6. This gas may have been pushed away from the center by an explosion 100,000 years ago. 7. From the orbital parameters of the stars near the center and Kepler s third law, we have calculated the mass of the nucleus to be 2 million solar masses. 8. The size of the nucleus is no more than 2 AU in diameter we see fluctuations in the nucleus over a time periods of 15 to 20 minutes. The size of the object is the distance light can travel in this time about 2 AU. 9. Something that small and that massive must be a black hole! Other Evidence: 1. Sgr A* does not move stars around it do, but it doesn t. 2. Evidence of black holes at the centers of other Galaxies as well.

7/5. Consequences of the principle of equivalence (#3) 1. Gravity is a manifestation of the curvature of space.

7/5. Consequences of the principle of equivalence (#3) 1. Gravity is a manifestation of the curvature of space. 7/5 Consequences of the principle of equivalence (#3) 1. Gravity is a manifestation of the curvature of space. Follow the path of a light pulse in an elevator accelerating in gravityfree space. The dashed

More information

Neutron Stars. Chapter 14: Neutron Stars and Black Holes. Neutron Stars. What s holding it up? The Lighthouse Model of Pulsars

Neutron Stars. Chapter 14: Neutron Stars and Black Holes. Neutron Stars. What s holding it up? The Lighthouse Model of Pulsars Neutron Stars Form from a 8-20 M Sun star Chapter 14: Neutron Stars and Black Holes Leftover 1.4-3 M Sun core after supernova Neutron Stars consist entirely of neutrons (no protons) Neutron Star (tennis

More information

Lecture Outlines. Chapter 22. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc.

Lecture Outlines. Chapter 22. Astronomy Today 8th Edition Chaisson/McMillan Pearson Education, Inc. Lecture Outlines Chapter 22 Astronomy Today 8th Edition Chaisson/McMillan Chapter 22 Neutron Stars and Black Holes Units of Chapter 22 22.1 Neutron Stars 22.2 Pulsars 22.3 Neutron-Star Binaries 22.4 Gamma-Ray

More information

ASTR Midterm 2 Phil Armitage, Bruce Ferguson

ASTR Midterm 2 Phil Armitage, Bruce Ferguson ASTR 1120-001 Midterm 2 Phil Armitage, Bruce Ferguson SECOND MID-TERM EXAM MARCH 21 st 2006: Closed books and notes, 1 hour. Please PRINT your name and student ID on the places provided on the scan sheet.

More information

Einstein s Gravity. Understanding space-time and the gravitational effects of mass

Einstein s Gravity. Understanding space-time and the gravitational effects of mass Einstein s Gravity Understanding space-time and the gravitational effects of mass Albert Einstein (1879-1955) One of the iconic figures of the 20 th century, Einstein revolutionized our understanding of

More information

The Galaxy. (The Milky Way Galaxy)

The Galaxy. (The Milky Way Galaxy) The Galaxy (The Milky Way Galaxy) Which is a picture of the Milky Way? A A is what we see from Earth inside the Milky Way while B is what the Milky Way might look like if we were far away looking back

More information

2. Can observe radio waves from the nucleus see a strong radio source there Sagittarius A* or Sgr A*.

2. Can observe radio waves from the nucleus see a strong radio source there Sagittarius A* or Sgr A*. 7/7 The Nucleus of the MW its center 1. Can t see the nucleus in visible light too much stuff in the way. 2. Can observe radio waves from the nucleus see a strong radio source there Sagittarius A* or Sgr

More information

Our Galaxy. We are located in the disk of our galaxy and this is why the disk appears as a band of stars across the sky.

Our Galaxy. We are located in the disk of our galaxy and this is why the disk appears as a band of stars across the sky. Our Galaxy Our Galaxy We are located in the disk of our galaxy and this is why the disk appears as a band of stars across the sky. Early attempts to locate our solar system produced erroneous results.

More information

Black Holes -Chapter 21

Black Holes -Chapter 21 Black Holes -Chapter 21 The most massive stellar cores If the core is massive enough (~3 M ; total initial mass of star > 25 M or so), even neutron degeneracy pressure can be overwhelmed by gravity. A

More information

ASTR 200 : Lecture 21. Stellar mass Black Holes

ASTR 200 : Lecture 21. Stellar mass Black Holes 1 ASTR 200 : Lecture 21 Stellar mass Black Holes High-mass core collapse Just as there is an upper limit to the mass of a white dwarf (the Chandrasekhar limit), there is an upper limit to the mass of a

More information

11/1/17. Important Stuff (Section 001: 9:45 am) Important Stuff (Section 002, 1:00 pm) 14.1 White Dwarfs. Chapter 14: The Bizarre Stellar Graveyard

11/1/17. Important Stuff (Section 001: 9:45 am) Important Stuff (Section 002, 1:00 pm) 14.1 White Dwarfs. Chapter 14: The Bizarre Stellar Graveyard 11/1/17 Important Stuff (Section 001: 9:45 am) The Second Midterm is Thursday, November 9 The Second Midterm will be given in a different room: Willey 175 Bring 2 pencils and a photo-id. In accordance

More information

Physics HW Set 3 Spring 2015

Physics HW Set 3 Spring 2015 1) If the Sun were replaced by a one solar mass black hole 1) A) life here would be unchanged. B) we would still orbit it in a period of one year. C) all terrestrial planets would fall in immediately.

More information

Centers of Galaxies. = Black Holes and Quasars

Centers of Galaxies. = Black Holes and Quasars Centers of Galaxies = Black Holes and Quasars Models of Nature: Kepler Newton Einstein (Special Relativity) Einstein (General Relativity) Motions under influence of gravity [23] Kepler The planets move

More information

Number of Stars: 100 billion (10 11 ) Mass : 5 x Solar masses. Size of Disk: 100,000 Light Years (30 kpc)

Number of Stars: 100 billion (10 11 ) Mass : 5 x Solar masses. Size of Disk: 100,000 Light Years (30 kpc) THE MILKY WAY GALAXY Type: Spiral galaxy composed of a highly flattened disk and a central elliptical bulge. The disk is about 100,000 light years (30kpc) in diameter. The term spiral arises from the external

More information

Chapter 26. Relativity

Chapter 26. Relativity Chapter 26 Relativity Time Dilation The vehicle is moving to the right with speed v A mirror is fixed to the ceiling of the vehicle An observer, O, at rest in this system holds a laser a distance d below

More information

Astronomy A BEGINNER S GUIDE TO THE UNIVERSE EIGHTH EDITION

Astronomy A BEGINNER S GUIDE TO THE UNIVERSE EIGHTH EDITION Astronomy A BEGINNER S GUIDE TO THE UNIVERSE EIGHTH EDITION CHAPTER 14 The Milky Way Galaxy Lecture Presentation 14.0 the Milky Way galaxy How do we know the Milky Way exists? We can see it even though

More information

1. Convective throughout deliver heat from core to surface purely by convection.

1. Convective throughout deliver heat from core to surface purely by convection. 6/30 Post Main Sequence Evolution: Low-Mass Stars 1. Convective throughout deliver heat from core to surface purely by convection. 2. Convection mixes the material of the star is the material carries the

More information

Black Holes, or the Monster at the Center of the Galaxy

Black Holes, or the Monster at the Center of the Galaxy Black Holes, or the Monster at the Center of the Galaxy Learning Objectives! How do black holes with masses a few times that of our Sun form? How can we observe such black holes?! Where and how might you

More information

Black Holes and Curved Space-time. Paths of Light and Matter. The Principle of Equivalence. Implications of Gravity Bending Light

Black Holes and Curved Space-time. Paths of Light and Matter. The Principle of Equivalence. Implications of Gravity Bending Light Black Holes and Curved Space-time When a massive star collapses at the end of its life, it can become a black hole A black is an object that is so massive that light cannot escape from it The theory that

More information

11/1/16. Important Stuff (Section 001: 9:45 am) Important Stuff (Section 002, 1:00 pm) 14.1 White Dwarfs. Chapter 14: The Bizarre Stellar Graveyard

11/1/16. Important Stuff (Section 001: 9:45 am) Important Stuff (Section 002, 1:00 pm) 14.1 White Dwarfs. Chapter 14: The Bizarre Stellar Graveyard Important Stuff (Section 001: 9:45 am) The Second Midterm is Thursday, November 10 The Second Midterm will be given in a different room: Willey 175 Bring 2 pencils and a photo-id. In accordance with the

More information

Special Relativity. Principles of Special Relativity: 1. The laws of physics are the same for all inertial observers.

Special Relativity. Principles of Special Relativity: 1. The laws of physics are the same for all inertial observers. Black Holes Special Relativity Principles of Special Relativity: 1. The laws of physics are the same for all inertial observers. 2. The speed of light is the same for all inertial observers regardless

More information

Review Special Relativity. February 3, Absolutes of Relativity. Key Ideas of Special Relativity. Path of Ball in a Moving Train

Review Special Relativity. February 3, Absolutes of Relativity. Key Ideas of Special Relativity. Path of Ball in a Moving Train February 3, 2009 Review Special Relativity General Relativity Key Ideas of Special Relativity No material object can travel faster than light If you observe something moving near light speed: Its time

More information

Notes for Wednesday, July 16; Sample questions start on page 2 7/16/2008

Notes for Wednesday, July 16; Sample questions start on page 2 7/16/2008 Notes for Wednesday, July 16; Sample questions start on page 2 7/16/2008 Wed, July 16 MW galaxy, then review. Start with ECP3Ch14 2 through 8 Then Ch23 # 8 & Ch 19 # 27 & 28 Allowed Harlow Shapely to locate

More information

Chapter 13 2/19/2014. Lecture Outline Neutron Stars. Neutron Stars and Black Holes Neutron Stars. Units of Chapter

Chapter 13 2/19/2014. Lecture Outline Neutron Stars. Neutron Stars and Black Holes Neutron Stars. Units of Chapter 13.1 Neutron Stars Lecture Outline Chapter 13 Neutron Stars and After a Type I supernova, little or nothing remains of the original star. After a Type II supernova, part of the core may survive. It is

More information

A100 Exploring the Universe: Black holes. Martin D. Weinberg UMass Astronomy

A100 Exploring the Universe: Black holes. Martin D. Weinberg UMass Astronomy A100 Exploring the Universe: Black holes Martin D. Weinberg UMass Astronomy weinberg@astro.umass.edu October 30, 2014 Read: S2, S3, Chap 18 10/30/14 slide 1 Sizes of s The solar neighborhood visualized!

More information

Evolution of High Mass stars

Evolution of High Mass stars Evolution of High Mass stars Neutron Stars A supernova explosion of a M > 8 M Sun star blows away its outer layers. The central core will collapse into a compact object of ~ a few M Sun. Pressure becomes

More information

Neutron Stars, Black Holes, Pulsars and More

Neutron Stars, Black Holes, Pulsars and More Neutron Stars, Black Holes, Pulsars and More October 30, 2002 1) Star Clusters 2) Type II Supernova 3) Neutron Stars 4) Black Holes 5) More Gravity Announcements Extra Credit there is an extra credit assignment

More information

Neutron Stars. Neutron Stars and Black Holes. The Crab Pulsar. Discovery of Pulsars. The Crab Pulsar. Light curves of the Crab Pulsar.

Neutron Stars. Neutron Stars and Black Holes. The Crab Pulsar. Discovery of Pulsars. The Crab Pulsar. Light curves of the Crab Pulsar. Chapter 11: Neutron Stars and Black Holes A supernova explosion of an M > 8 M sun star blows away its outer layers. Neutron Stars The central core will collapse into a compact object of ~ a few M sun.

More information

Einstein s Relativity and Black Holes

Einstein s Relativity and Black Holes Einstein s Relativity and Black Holes Guiding Questions 1. What are the two central ideas behind Einstein s special theory of relativity? 2. How do astronomers search for black holes? 3. In what sense

More information

General Relativity. In GR, mass (or energy) warps the spacetime fabric of space.

General Relativity. In GR, mass (or energy) warps the spacetime fabric of space. General Relativity Einstein s theory of General Relativity is a theory of gravity The basic idea is to drop Newton s idea of a mysterious force between masses and replace it with the 4-dimensional SpaceTime

More information

Astronomy 182: Origin and Evolution of the Universe

Astronomy 182: Origin and Evolution of the Universe Astronomy 182: Origin and Evolution of the Universe Prof. Josh Frieman Lecture 6 Oct. 28, 2015 Today Wrap up of Einstein s General Relativity Curved Spacetime Gravitational Waves Black Holes Relativistic

More information

Survey of Astrophysics A110

Survey of Astrophysics A110 Black Holes Goals: Understand Special Relativity General Relativity How do we observe black holes. Black Holes A consequence of gravity Massive neutron (>3M ) cannot be supported by degenerate neutron

More information

Stars and Galaxies 1

Stars and Galaxies 1 Stars and Galaxies 1 Characteristics of Stars 2 Star - body of gases that gives off great amounts of radiant energy as light and heat 3 Most stars look white but are actually different colors Antares -

More information

Relativity and Black Holes

Relativity and Black Holes Relativity and Black Holes Post-MS Evolution of Very High Mass (>15 M Θ ) Stars similar to high mass except more rapid lives end in Type II supernova explosions main difference: mass of iron core at end

More information

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way. The Curtis View. Our Galaxy. The Shapley View 3/27/18

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way. The Curtis View. Our Galaxy. The Shapley View 3/27/18 Astronomy 113 Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way 14-2 Historical Overview: the Curtis-Shapley Debate ³What is the size of our galaxy? ³What is the nature of spiral nebula? The Curtis

More information

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Dr. Joseph E. Pesce, Ph.D.

Astronomy 113. Dr. Joseph E. Pesce, Ph.D. Dr. Joseph E. Pesce, Ph.D. Astronomy 113 Dr. Joseph E. Pesce, Ph.D. Distances & the Milky Way Historical Overview: the Curtis-Shapley Debate ³What is the size of our galaxy? ³What is the nature of spiral nebula? 14-2 ³Occurred in

More information

Directed Reading A. Section: The Life Cycle of Stars TYPES OF STARS THE LIFE CYCLE OF SUNLIKE STARS A TOOL FOR STUDYING STARS.

Directed Reading A. Section: The Life Cycle of Stars TYPES OF STARS THE LIFE CYCLE OF SUNLIKE STARS A TOOL FOR STUDYING STARS. Skills Worksheet Directed Reading A Section: The Life Cycle of Stars TYPES OF STARS (pp. 444 449) 1. Besides by mass, size, brightness, color, temperature, and composition, how are stars classified? a.

More information

Test #3 Next Tuesday, Nov. 8 Bring your UNM ID! Bring two number 2 pencils. Announcements. Review for test on Monday, Nov 7 at 3:25pm

Test #3 Next Tuesday, Nov. 8 Bring your UNM ID! Bring two number 2 pencils. Announcements. Review for test on Monday, Nov 7 at 3:25pm Test #3 Next Tuesday, Nov. 8 Bring your UNM ID! Bring two number 2 pencils Announcements Review for test on Monday, Nov 7 at 3:25pm Neutron Star - Black Hole merger Review for Test #3 Nov 8 Topics: Stars

More information

Chapter 13 Notes The Deaths of Stars Astronomy Name: Date:

Chapter 13 Notes The Deaths of Stars Astronomy Name: Date: Chapter 13 Notes The Deaths of Stars Astronomy Name: Date: I. The End of a Star s Life When all the fuel in a star is used up, will win over pressure and the star will die nuclear fuel; gravity High-mass

More information

For instance, due to the solar wind, the Sun will lose about 0.1% of its mass over its main sequence existence.

For instance, due to the solar wind, the Sun will lose about 0.1% of its mass over its main sequence existence. 7/7 For instance, due to the solar wind, the Sun will lose about 0.1% of its mass over its main sequence existence. Once a star evolves off the main sequence, its mass changes more drastically. Some stars

More information

Astronomy Ch. 22 Neutron Stars and Black Holes. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

Astronomy Ch. 22 Neutron Stars and Black Holes. MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. Name: Period: Date: Astronomy Ch. 22 Neutron Stars and Black Holes MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) In a neutron star, the core

More information

The Milky Way Galaxy

The Milky Way Galaxy 1/5/011 The Milky Way Galaxy Distribution of Globular Clusters around a Point in Sagittarius About 00 globular clusters are distributed in random directions around the center of our galaxy. 1 1/5/011 Structure

More information

How does the galaxy rotate and keep the spiral arms together? And what really lies at the center of the galaxy?

How does the galaxy rotate and keep the spiral arms together? And what really lies at the center of the galaxy? Ch 14: Mysteries of the Milky Way How does the galaxy rotate and keep the spiral arms together? And what really lies at the center of the galaxy? The Structure of the Galaxy We know that our galaxy has

More information

ASTR 200 : Lecture 30. More Gravity: Tides, GR, and Gravitational Waves

ASTR 200 : Lecture 30. More Gravity: Tides, GR, and Gravitational Waves ASTR 200 : Lecture 30 More Gravity: Tides, GR, and Gravitational Waves 1 Topic One : Tides Differential tidal forces on the Earth. 2 How do tides work???? Think about 3 billiard balls sitting in space

More information

Syllabus and Schedule for ASTRO 210 (Black Holes)

Syllabus and Schedule for ASTRO 210 (Black Holes) Black Holes Syllabus and Schedule for ASTRO 210 (Black Holes) The syllabus and schedule for this class are located at: http://chartasg.people.cofc.edu/chartas/teaching.html Gravity is Universal Gravity

More information

Beyond Our Solar System Chapter 24

Beyond Our Solar System Chapter 24 Beyond Our Solar System Chapter 24 PROPERTIES OF STARS Distance Measuring a star's distance can be very difficult Stellar parallax Used for measuring distance to a star Apparent shift in a star's position

More information

The Milky Way - Chapter 23

The Milky Way - Chapter 23 The Milky Way - Chapter 23 The Milky Way Galaxy A galaxy: huge collection of stars (10 7-10 13 ) and interstellar matter (gas & dust). Held together by gravity. Much bigger than any star cluster we have

More information

The Milky Way Galaxy (ch. 23)

The Milky Way Galaxy (ch. 23) The Milky Way Galaxy (ch. 23) [Exceptions: We won t discuss sec. 23.7 (Galactic Center) much in class, but read it there will probably be a question or a few on it. In following lecture outline, numbers

More information

5) Which stage lasts the longest? a) viii b) I c) iv d) iii e) vi

5) Which stage lasts the longest? a) viii b) I c) iv d) iii e) vi 1) Which of the following statements about globular clusters is false? a) Globular cluster stars are very metal- poor relative to the Sun. b) Globular cluster stars are more than 12 billion years old.

More information

Exam # 3 Tue 12/06/2011 Astronomy 100/190Y Exploring the Universe Fall 11 Instructor: Daniela Calzetti

Exam # 3 Tue 12/06/2011 Astronomy 100/190Y Exploring the Universe Fall 11 Instructor: Daniela Calzetti Exam # 3 Tue 12/06/2011 Astronomy 100/190Y Exploring the Universe Fall 11 Instructor: Daniela Calzetti INSTRUCTIONS: Please, use the `bubble sheet and a pencil # 2 to answer the exam questions, by marking

More information

Cosmology, Galaxies, and Stars OUR VISIBLE UNIVERSE

Cosmology, Galaxies, and Stars OUR VISIBLE UNIVERSE Cosmology, Galaxies, and Stars OUR VISIBLE UNIVERSE Cosmology Cosmology is the study of the universe; its nature, origin and evolution. General Relativity is the mathematical basis of cosmology from which

More information

Chapter 18 The Bizarre Stellar Graveyard

Chapter 18 The Bizarre Stellar Graveyard Chapter 18 The Bizarre Stellar Graveyard 18.1 White Dwarfs Our goals for learning What is a white dwarf? What can happen to a white dwarf in a close binary system? What is a white dwarf? White Dwarfs White

More information

NSCI 314 LIFE IN THE COSMOS

NSCI 314 LIFE IN THE COSMOS NSCI 314 LIFE IN THE COSMOS 2 BASIC ASTRONOMY, AND STARS AND THEIR EVOLUTION Dr. Karen Kolehmainen Department of Physics CSUSB COURSE WEBPAGE: http://physics.csusb.edu/~karen MOTIONS IN THE SOLAR SYSTEM

More information

ASTR 200 : Lecture 31. More Gravity: Tides, GR, and Gravitational Waves

ASTR 200 : Lecture 31. More Gravity: Tides, GR, and Gravitational Waves ASTR 200 : Lecture 31 More Gravity: Tides, GR, and Gravitational Waves 1 Topic One : Tides Differential tidal forces on the Earth. 2 How do tides work???? Think about 3 billiard balls sitting in space

More information

Structure of the Milky Way. Structure of the Milky Way. The Milky Way

Structure of the Milky Way. Structure of the Milky Way. The Milky Way Key Concepts: Lecture 29: Our first steps into the Galaxy Exploration of the Galaxy: first attempts to measure its structure (Herschel, Shapley). Structure of the Milky Way Initially, star counting was

More information

Chapter S3 Spacetime and Gravity. Agenda. Distinguishing Crackpots

Chapter S3 Spacetime and Gravity. Agenda. Distinguishing Crackpots Chapter S3 Spacetime and Gravity Agenda Announce: Online Quizzes Observations Extra Credit Lecture Distinguishing Crackpot/Genuine Science Review of Special Relativity General Relativity Distinguishing

More information

22. Black Holes. Relativistic Length Contraction. Relativistic Time Dilation

22. Black Holes. Relativistic Length Contraction. Relativistic Time Dilation 22. Black Holes Einstein s Special Theory of Relativity Einstein s General Theory of Relativity Black holes exist in some binary star systems Supermassive black holes at of galaxy centers Two properties

More information

Stellar remnants II. Neutron Stars 10/18/2010. (progenitor star 1.4 < M< 3 Msun) Stars, Galaxies & the Universe Announcements

Stellar remnants II. Neutron Stars 10/18/2010. (progenitor star 1.4 < M< 3 Msun) Stars, Galaxies & the Universe Announcements Stars, Galaxies & the Universe Announcements Exam #2 on Wednesday Review sheet and study guide posted by Thursday Use office hours and Astronomy Tutorial hours Covers material since Exam #1 (plus background

More information

Chapter 14 The Milky Way Galaxy

Chapter 14 The Milky Way Galaxy Chapter 14 The Milky Way Galaxy Spiral Galaxy M81 - similar to our Milky Way Galaxy Our Parent Galaxy A galaxy is a giant collection of stellar and interstellar matter held together by gravity Billions

More information

SPECIAL RELATIVITY! (Einstein 1905)!

SPECIAL RELATIVITY! (Einstein 1905)! SPECIAL RELATIVITY! (Einstein 1905)! Motivations:! Explaining the results of the Michelson-Morley! experiment without invoking a force exerted! on bodies moving through the aether.! Make the equations

More information

The Milky Way, Hubble Law, the expansion of the Universe and Dark Matter Chapter 14 and 15 The Milky Way Galaxy and the two Magellanic Clouds.

The Milky Way, Hubble Law, the expansion of the Universe and Dark Matter Chapter 14 and 15 The Milky Way Galaxy and the two Magellanic Clouds. The Milky Way, Hubble Law, the expansion of the Universe and Dark Matter Chapter 14 and 15 The Milky Way Galaxy and the two Magellanic Clouds. Image taken from the European Southern Observatory in Chile

More information

Lecture 10: General Relativity I

Lecture 10: General Relativity I Lecture 10: General Relativity I! Recap: Special Relativity and the need for a more general theory! The strong equivalence principle! Gravitational time dilation! Curved space-time & Einstein s theory

More information

Accretion Disks. Review: Stellar Remnats. Lecture 12: Black Holes & the Milky Way A2020 Prof. Tom Megeath 2/25/10. Review: Creating Stellar Remnants

Accretion Disks. Review: Stellar Remnats. Lecture 12: Black Holes & the Milky Way A2020 Prof. Tom Megeath 2/25/10. Review: Creating Stellar Remnants Lecture 12: Black Holes & the Milky Way A2020 Prof. Tom Megeath Review: Creating Stellar Remnants Binaries may be destroyed in white dwarf supernova Binaries be converted into black holes Review: Stellar

More information

Class 16. Prof J. Kenney October 31, Relativity

Class 16. Prof J. Kenney October 31, Relativity Class 16 Prof J. Kenney October 31, 2016 Relativity Length contraction (moving sticks are shorter) A measuring stick at rest has a length Lo. When it is propelled at velocity v, it has a shorter length

More information

It is possible for a couple of elliptical galaxies to collide and become a spiral and for two spiral galaxies to collide and form an elliptical.

It is possible for a couple of elliptical galaxies to collide and become a spiral and for two spiral galaxies to collide and form an elliptical. 7/16 Ellipticals: 1. Very little gas and dust an no star formation. 2. Composed of old stars. 3. Masses range from hundreds of thousands to 10's of trillions of solar masses. 4. Sizes range from 3000 ly

More information

Sag A Mass.notebook. September 26, ' x 8' visual image of the exact center of the Milky Way

Sag A Mass.notebook. September 26, ' x 8' visual image of the exact center of the Milky Way 8' x 8' visual image of the exact center of the Milky Way The actual center is blocked by dust and is not visible. At the distance to the center (26,000 ly), this image would span 60 ly. This is the FOV

More information

RELATIVITY. The End of Physics? A. Special Relativity. 3. Einstein. 2. Michelson-Morley Experiment 5

RELATIVITY. The End of Physics? A. Special Relativity. 3. Einstein. 2. Michelson-Morley Experiment 5 1 The End of Physics? RELATIVITY Updated 01Aug30 Dr. Bill Pezzaglia The following statement made by a Nobel prize winning physicist: The most important fundamental laws and facts of physical science have

More information

Black Holes Thursday, 14 March 2013

Black Holes Thursday, 14 March 2013 Black Holes General Relativity Intro We try to explain the black hole phenomenon by using the concept of escape velocity, the speed to clear the gravitational field of an object. According to Newtonian

More information

Chapter 23 The Milky Way Galaxy Pearson Education, Inc.

Chapter 23 The Milky Way Galaxy Pearson Education, Inc. Chapter 23 The Milky Way Galaxy The Milky Way is our own galaxy viewed from the inside. It is a vast collection of more than 200 billion stars, planets, nebulae, clusters, dust and gas. Our own sun and

More information

Our Galaxy. Chapter Twenty-Five. Guiding Questions

Our Galaxy. Chapter Twenty-Five. Guiding Questions Our Galaxy Chapter Twenty-Five Guiding Questions 1. What is our Galaxy? How do astronomers know where we are located within it? 2. What is the shape and size of our Galaxy? 3. How do we know that our Galaxy

More information

Chapter 18 The Bizarre Stellar Graveyard. White Dwarfs. What is a white dwarf? Size of a White Dwarf White Dwarfs

Chapter 18 The Bizarre Stellar Graveyard. White Dwarfs. What is a white dwarf? Size of a White Dwarf White Dwarfs Chapter 18 The Bizarre Stellar Graveyard 18.1 White Dwarfs Our goals for learning What is a white dwarf? What can happen to a white dwarf in a close binary system? What is a white dwarf? White Dwarfs White

More information

Our Galaxy. Milky Way Galaxy = Sun + ~100 billion other stars + gas and dust. Held together by gravity! The Milky Way with the Naked Eye

Our Galaxy. Milky Way Galaxy = Sun + ~100 billion other stars + gas and dust. Held together by gravity! The Milky Way with the Naked Eye Our Galaxy Milky Way Galaxy = Sun + ~100 billion other stars + gas and dust Held together by gravity! The Milky Way with the Naked Eye We get a special view of our own galaxy because we are part of it!

More information

Space and Time Before Einstein. The Problem with Light. Admin. 11/2/17. Key Concepts: Lecture 28: Relativity

Space and Time Before Einstein. The Problem with Light. Admin. 11/2/17. Key Concepts: Lecture 28: Relativity Admin. 11/2/17 1. Class website http://www.astro.ufl.edu/~jt/teaching/ast1002/ 2. Optional Discussion sections: Tue. ~11.30am (period 5), Bryant 3; Thur. ~12.30pm (end of period 5 and period 6), start

More information

Stellar Evolution: Outline

Stellar Evolution: Outline Stellar Evolution: Outline Interstellar Medium (dust) Hydrogen and Helium Small amounts of Carbon Dioxide (makes it easier to detect) Massive amounts of material between 100,000 and 10,000,000 solar masses

More information

Lecture 18 : Black holes. Astronomy 111

Lecture 18 : Black holes. Astronomy 111 Lecture 18 : Black holes Astronomy 111 Gravity's final victory A star more massive than about 18 M sun would leave behind a post-supernova core this is larger than 2-3 M sun :Neutron degeneracy pressure

More information

Mr Green sees the shorter, straight, green path and Mr. Red sees the longer, curved, red path.

Mr Green sees the shorter, straight, green path and Mr. Red sees the longer, curved, red path. Mr Green sees the shorter, straight, green path and Mr. Red sees the longer, curved, red path. In an accelerated frame, time runs slow compared to a non-accelerated frame. The Equivalence Principle tells

More information

Chapter 13: The Stellar Graveyard

Chapter 13: The Stellar Graveyard Chapter 13: The Stellar Graveyard Habbal Astro110 http://chandra.harvard.edu/photo/2001/1227/index.html Chapter 13 Lecture 26 1 Low mass star High mass (>8 M sun ) star Ends as a white dwarf. Ends in a

More information

Name Final Exam December 7, 2015

Name Final Exam December 7, 2015 Name Final Exam December 7, 015 This test consists of five parts. Please note that in parts II through V, you can skip one question of those offered. Part I: Multiple Choice (mixed new and review questions)

More information

Arvind Borde / AST 10, Week 2: Our Home: The Milky Way

Arvind Borde / AST 10, Week 2: Our Home: The Milky Way Arvind Borde / AST 10, Week 2: Our Home: The Milky Way The Milky Way is our home galaxy. It s a collection of stars, gas and dust. (1) What holds it together? Its self-gravity. (2) What did the last slide

More information

Astronomy 421. Lecture 24: Black Holes

Astronomy 421. Lecture 24: Black Holes Astronomy 421 Lecture 24: Black Holes 1 Outline General Relativity Equivalence Principle and its Consequences The Schwarzschild Metric The Kerr Metric for rotating black holes Black holes Black hole candidates

More information

Chapter 14: The Bizarre Stellar Graveyard

Chapter 14: The Bizarre Stellar Graveyard Lecture Outline Chapter 14: The Bizarre Stellar Graveyard 14.1 White Dwarfs Our goals for learning: What is a white dwarf? What can happen to a white dwarf in a close binary system? What is a white dwarf?

More information

A100H Exploring the Universe: Black holes. Martin D. Weinberg UMass Astronomy

A100H Exploring the Universe: Black holes. Martin D. Weinberg UMass Astronomy A100H Exploring the Universe: Black holes Martin D. Weinberg UMass Astronomy astron100h-mdw@courses.umass.edu March 22, 2016 Read: S2, S3, Chap 18 03/22/16 slide 1 Exam #2: March 29 One week from today!

More information

Lecture 25 The Milky Way Galaxy November 29, 2017

Lecture 25 The Milky Way Galaxy November 29, 2017 Lecture 25 The Milky Way Galaxy November 29, 2017 1 2 Size of the Universe The Milky Way galaxy is very much larger than the solar system Powers of Ten interactive applet 3 Galaxies Large collections of

More information

Study Guide Chapter 2

Study Guide Chapter 2 Section: Stars Pages 32-38 Study Guide Chapter 2 Circle the letter of the best answer for each question. 1. What do scientists study to learn about stars? a. gravity c. space b. starlight d. colors COLOR

More information

Lecture 29. Our Galaxy: "Milky Way"

Lecture 29. Our Galaxy: Milky Way Lecture 29 The Milky Way Galaxy Disk, Bulge, Halo Rotation Curve Galactic Center Apr 3, 2006 Astro 100 Lecture 29 1 Our Galaxy: "Milky Way" Milky, diffuse band of light around sky known to ancients. Galileo

More information

Relativity. Class 16 Prof J. Kenney June 18, boss

Relativity. Class 16 Prof J. Kenney June 18, boss Relativity Class 16 Prof J. Kenney June 18, 2018 boss Length contraction (moving sticks are shorter) A measuring stick at rest has a length Lo. When it is propelled at velocity v, it has a shorter length

More information

Our Solar System: A Speck in the Milky Way

Our Solar System: A Speck in the Milky Way GALAXIES Lesson 2 Our Solar System: A Speck in the Milky Way The Milky Way appears to be curved when we view it but in reality it is a straight line. It is curved due to the combination of pictures taken

More information

General Relativity and Cosmology. The End of Absolute Space Cosmological Principle Black Holes CBMR and Big Bang

General Relativity and Cosmology. The End of Absolute Space Cosmological Principle Black Holes CBMR and Big Bang General Relativity and Cosmology The End of Absolute Space Cosmological Principle Black Holes CBMR and Big Bang The End of Absolute Space (AS) Special Relativity (SR) abolished AS only for the special

More information

The Milky Way Galaxy. Some thoughts. How big is it? What does it look like? How did it end up this way? What is it made up of?

The Milky Way Galaxy. Some thoughts. How big is it? What does it look like? How did it end up this way? What is it made up of? Some thoughts The Milky Way Galaxy How big is it? What does it look like? How did it end up this way? What is it made up of? Does it change 2 3 4 5 This is not a constant zoom The Milky Way Almost everything

More information

Beyond the Solar System 2006 Oct 17 Page 1 of 5

Beyond the Solar System 2006 Oct 17 Page 1 of 5 I. Stars have color, brightness, mass, temperature and size. II. Distances to stars are measured using stellar parallax a. The further away, the less offset b. Parallax angles are extremely small c. Measured

More information

Galaxies and Star Systems

Galaxies and Star Systems Chapter 5 Section 5.1 Galaxies and Star Systems Galaxies Terms: Galaxy Spiral Galaxy Elliptical Galaxy Irregular Galaxy Milky Way Galaxy Quasar Black Hole Types of Galaxies A galaxy is a huge group of

More information

Stars, Galaxies & the Universe Lecture Outline

Stars, Galaxies & the Universe Lecture Outline Stars, Galaxies & the Universe Lecture Outline A galaxy is a collection of 100 billion stars! Our Milky Way Galaxy (1)Components - HII regions, Dust Nebulae, Atomic Gas (2) Shape & Size (3) Rotation of

More information

What is a Black Hole?

What is a Black Hole? What is a Black Hole? Robert H. Gowdy Virginia Commonwealth University December 2016 Bob G (VCU) Black Holes December 2016 1 / 29 Black Holes Bob G (VCU) Black Holes December 2016 2 / 29 Overview Spacetime

More information

One of the factors that misled Herschel into concluding that we are at the Universe's center was

One of the factors that misled Herschel into concluding that we are at the Universe's center was Homework 11! This is a preview of the draft version of the quiz Started: Apr 14 at 9:17am Quiz Instruc!ons Question 1 One of the factors that misled Herschel into concluding that we are at the Universe's

More information

Chapter 14. Outline. Neutron Stars and Black Holes. Note that the following lectures include. animations and PowerPoint effects such as

Chapter 14. Outline. Neutron Stars and Black Holes. Note that the following lectures include. animations and PowerPoint effects such as Note that the following lectures include animations and PowerPoint effects such as fly ins and transitions that require you to be in PowerPoint's Slide Show mode (presentation mode). Chapter 14 Neutron

More information

General Relativity and Black Holes

General Relativity and Black Holes General Relativity and Black Holes Lecture 19 1 Lecture Topics General Relativity The Principal of Equivalence Consequences of General Relativity slowing of clocks curvature of space-time Tests of GR Escape

More information

29:50 Stars, Galaxies, and the Universe Second Hour Exam November 10, 2010 Form A

29:50 Stars, Galaxies, and the Universe Second Hour Exam November 10, 2010 Form A 29:50 Stars, Galaxies, and the Universe Second Hour Exam November 10, 2010 Form A There are 20 questions (Note: There will be 32 on the real thing). Read each question and all of the choices before choosing.

More information

Chapter 18 Lecture. The Cosmic Perspective Seventh Edition. The Bizarre Stellar Graveyard Pearson Education, Inc.

Chapter 18 Lecture. The Cosmic Perspective Seventh Edition. The Bizarre Stellar Graveyard Pearson Education, Inc. Chapter 18 Lecture The Cosmic Perspective Seventh Edition The Bizarre Stellar Graveyard The Bizarre Stellar Graveyard 18.1 White Dwarfs Our goals for learning: What is a white dwarf? What can happen to

More information

TAKE A LOOK 2. Identify This star is in the last stage of its life cycle. What is that stage?

TAKE A LOOK 2. Identify This star is in the last stage of its life cycle. What is that stage? CHAPTER 15 2 SECTION Stars, Galaxies, and the Universe The Life Cycle of Stars BEFORE YOU READ After you read this section, you should be able to answer these questions: How do stars change over time?

More information

White dwarfs are the remaining cores of dead stars. Electron degeneracy pressure supports them against the crush of gravity. The White Dwarf Limit

White dwarfs are the remaining cores of dead stars. Electron degeneracy pressure supports them against the crush of gravity. The White Dwarf Limit The Bizarre Stellar Graveyard Chapter 18 Lecture The Cosmic Perspective 18.1 White Dwarfs Our goals for learning: What is a white dwarf? What can happen to a white dwarf in a close binary system? Seventh

More information