Astronomy 2142: Black Holes
Autumn 2025

Slides from lectures:

• Introduction slides in pdf or pptx.
• A few slides on Newton in pdf or pptx.
• Slides for the 9/17 in-class question in pdf or pptx.
• Illustrations from Mr. Tompkins in Wonderland, by George Gamow.
• Empirical evidence for General Relativity in pdf or ptx.
• White dwarfs, supernovae, neutron stars in pdf or pptx.
• Stellar mass black holes in pdf or pptx.
• Quasars and supermassive black holes in pdf or pptx.
• Dan Wilkins's slides on X-ray studies of BH accretion disks: pdf.
• Gravitational waves in pptx or pdf (reposted 11/24/25 with small revisions).
• Imaging Black Hole Event Horizons in pptx or pdf (reposted 12/3/25 with a new final slide).
• Final lecture on black hole frontiers, in pptx or pdf

Homework assignments:

• Homework 1: Newton's Law of Gravity, due on Monday, September 22, 5 pm.
• Solution set handed out on 9/26.
• Homework 2: Solar Energy and Time Dilation, due on Friday, October 3, 7 pm.
• Solution set handed out on 10/9.
• Homework 3: White Dwarfs, Neutron Stars, and Black Holes, i due on Friday, November 7, 7 pm.
• Solution set handed out.
• Homework 4: Supermassive Black Holes and Gravitational Waves, due on Monday, November 24, 7 pm.
• Solution set handed out on 12/3.
• Recovery homework assignment, if you scored below 70\% on one of the four assignments. Due on Thursday, Dec 11, 7 pm.

Information sheets:

• Manipulating equations. To help you remember some rules of algebra that you might have forgotten.
• Scientific notation. Some reminders on scientific notation and test problems to check that you can use it correctly on your calculator.
• Reader's guide for Black Holes and Time Warps, written by DW, last update 8/29/25.
• Review guide for the midterm exam, posted 10/3/25. (Exam is on 10/13/25.)
• Solution sheet for the midterm exam was handed out in class, on paper only.
• Highlight calculations from A2142, a reminder of the most important calculations we have done through the course. Posted 12/1/25.
• Review guide for the final exam, posted 12/5/25. (Exam is on 12/18.)
  Please note that the narrative student evaluation is the 3rd page of the review guide. You should complete this evaluation while reviewing for the final and bring it with you to the exam.

Videos or images shown in class:

• Earth orbiting a black hole, an animation by Andrew Hamilton
• Stars orbiting the Milky Way black hole
• Kepler's laws
• Relativity of simultaneity: image and video.
• Time dilation: image and video.
• Excerpt from Mr. Tompkins in Wonderland, by George Gamow.
• Shoot-the-monkey illustration of the equivalence principle.
• Einstein's elevator, a simple demonstration that objects travel on straight paths in a freely falling reference frame.
• Weightlessness in the International Space Station
• Black hole waterfall description from Andrew Hamilton's Inside Black Holes web site.
• A new way to visualize General Relativity. This video proposes an alternative to the conventional "rubber sheet" visualization of curved spacetime, one that better represents what is going on in GR.
• Now a set of items related to LIGO and gravitational wave detection; these and others can be found at this LIGO website
  • Kip Thorne interview on gravitational waves"
  • The journey of a gravitational wave discovered by LIGO in 2015.
  • Interferometer response to a gravitational wave
  • Black hole merger ripples in a spacetime pond
  • Gravitational wave chirp
  • Simultaneous gravitational and electromagnetic detection of a neutron star merger
  • LIGO signal from a binary neutron star merger
• Inspiral calculation for a supermassive black hole. This video shows the predicted orbit of a stellar mass black hole orbiting a spinning supermassive black hole and eventually merging. This kind of event should be detectable with LISA, but not with LIGO.
• Similar inspiral calculation for a supermassive black hole; this movie stops at several points and shows you the patterns.
• Zoom out from the Event Horizon Telescope image of the M87 black hole.
• BBC video clip on Hawking radiation. I showed a few of minutes of this 7-minute video in class. While this video is generally good, if you aren't careful you will come away with the very incorrect impression that Hawking radiation is what we see when we observe distant black holes, whereas what we see is actually emission from accreting gas outside the event horizon.
• Excerpts from the book The Large Scale Structure of Spacetime, by Stephen Hawking and George Ellis (1973). I showed this so that you can admire the figures.

Other links, some to videos, some to informational web sites or images:

• Death by black hole.
  A conversation with the always-entertaining Neil DeGrasse Tyson.
• A journey into a black hole. This 7-minute video has quite good (and carefully calculated) visualizations and narration explaining what is going on.
• The Black Hole. Not what they are really like.`
• Frames of Reference. I vividly remember this science film from high school physics class; even then it was comically retro. Someone has broken it into chunks and posted it to YouTube. We will watch the first few minutes of Part 1 in class. Part 3 is my favorite.
  Part 1.
  Part 2.
  Part 3.
  Part 4.
  
• Excerpts from English translations of Einstein's 1905 papers On the Electrodynamics of Moving Bodies and Does the Inertia of a Body Depend Upon Its Energy Content?.
• Sound of a pulsar. The image shows the Vela supernova remnant, and the sound is a translation of the central pulsar's pulsating radio signal into sound.
• Visual summary of GR. This video, by the same animator as the "new way to visualize General Relativity" above, covers GR more broadly, from the equivalence principle to black holes.
• Kip Thorne interview on spacetime (14 mins).
• Scenes and interviews on the first LIGO discovery (3 mins)
• The article from the LIGO team on the first gravitational wave discovery.
• Next Generation Event Horizon Telescope. This web site provides a lot of explanation, images, and videos about event horizon imaging, and a detailed description of plans to upgrade the Event Horizon Telescope.
• Fuzzballs. A (16-minute) video discussing the black hole information paradox and the proposed solution based on string theory ``fuzzballs'' from OSU Physics professor Samir Mathur. This is an advanced topic, but the explanation in this video is very good, and accurate.

Links to videos available for extra credit assignments

• Interstellar Monthly Movie Night Panel, for the recording see here.
• Arrival Monthly Movie Night Panel, for the recording see here.

Links to black hole astronomy articles that I mentioned in class

• Spinning into the Gap
• NANOGrav
• Mass of MCG-06-30-15
• Little Red Dots
• Testing Hawking
• Visiting the closest BH
• BH destroys a star?
• Million Msun object found with gravitational lensing
• Big BHs in Little Red Dots
• Growing big BHs in star clusters
• A super-Eddington BH at z=3.4
• Changing Look AGN from disk tearing
• Improved imaging algorithms for the Event Horizon Telescope
• Testing GR with future event horizon imaging