An Online Class in Astrophysics

The non amateur stuff. Hawking, black holes, that sort of thing

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mikemarotta
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An Online Class in Astrophysics

Post by mikemarotta »

I recently completed an online class offered by the École polytechnique fédérale de Lausanne through edX, a program created by Harvard and MIT and now involving many other institutions. I recommend this class with serious reservations.

If you want a structured experience in learning astrophysics on your own, this can help. I found the content informative, challenging, and edifying. However, the presentation was often marred by careless transcription and poor translation of the lectures. I do grant that as listed, Physics 209, this is about what I would expect from an American university for a sophomore class in physics, though for non-majors. Calculus is at a minimum here. If you did well at “Conceptual Physics” and have a head for algebra, this is a solid survey of topics in astrophysics.

Nominally, the course takes seven weeks to work through seven chapters which are presented as 27 lectures and quizzes. Each lecture is about 20 to 35 minutes. There is a thin textbook that you can download as a PDF. I found it helpful. I printed some of it out and captured equations from other pages to include in my own notes.

I took the course for certification. So, I paid the registration fee of USD 139. Personally, I need that kind of motivation. If I had not been financially invested in the outcome, I would have walked away from it—which I also considered. More than once, I almost cut my losses and left the money on the table. Instead, I toughed it out and actually earned the certificate of completion a little more than halfway through the class because at that point, it was arithmetically impossible for me to fail. Nonetheless, my notebook is filled with answers copied “from the back of the book.”

First, and foremost, I do not have the mindset of a physicist or I would have become one a long, long time ago. So, for some problems, I had to see how it was done, what approach was needed, which contexts were relevant, where the equations of solution had to come from. So, that was learning. I missed a couple of others just because I did not understand what was being asked.

I also invested a lot of time into correcting the transcripts of the lectures. The English language speaker did not understand the material he was reading. Often, he spoke “v” for the Greek letter nu and “p” for rho, and so on. Sometimes he left symbols out entirely. Once, he spoke “proton” for “photon.” The course was replete with such problems. In one way, the careless transcription of text gave me the opportunity to read and review the lecture in detail. I formatted paragraphs and formatted equations. The fact remains that some lecture notes lacked any punctuation.

A more subtle difficulty was in the differences between sentence structure in French and English. The English speaker paused when the professor did, even though the thoughts presented as subordinate clauses, parenthetical comments, noted asides, or dependent clauses were strung differently in the two languages.

Despite the fact that the course was supposedly monitored by a professor and three assistants, in point of fact, no one monitored the course. When I finally tried to send an email the EPFL coordinator, the message bounced as undeliverable. So, you are on your own here.
Michael E. Marotta
Explore Scientific 102 mm Refractor
National Geographic 70 mm Refractor
Ploessl oculars 40mm to 6mm 2X Barlow
mike49mercury@gmail.com
mikemarotta
Posts: 107
Joined: Fri Dec 04, 2020 7:04 pm
Location: Austin, Texas, USA
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Re: An Online Class in Astrophysics

Post by mikemarotta »

Quote:
The grading system is simple. Each video is followed by several quizz, either multiple choice questions or questions requesting a numerical answer. In most cases it is possible to try 2-3 answers before giving the final answer. You qualify for the certificate with at least 50% of correct answers for at least 19 out of the 22 quizz that we propose.

When a numerical answer is required, usually, a 10% error bar is included in the calculation, more if it's an order of magnitude estimate.


Week 1: General introduction - Kepler's Laws - Virial theorem.
Week 2: Radiation processes - Line radiation - Black body - Measuring radiation.
Week 3: Doppler-Fizeau effect and astrophysical applications - Interstellar and intergalactic radiation - Strömgroen sphere - Absorption/emission - Color index - Tidal forces.
Week 4: Roche limit - Comets - Planetary energy balance - Planetary atmospheres -
Week 5: Stellar formation - Stellar classification - Stellar evolution.
Week 6: The galaxies - Rotation of the Milky Way and Oort constants - Dark matter.
Week 7: Fundamentals of cosmology - Distance ladder - Gravitational lensing.

Length: 7 Weeks
Effort: 3–4 hours per week
Michael E. Marotta
Explore Scientific 102 mm Refractor
National Geographic 70 mm Refractor
Ploessl oculars 40mm to 6mm 2X Barlow
mike49mercury@gmail.com
mikemarotta
Posts: 107
Joined: Fri Dec 04, 2020 7:04 pm
Location: Austin, Texas, USA
Contact:

Re: An Online Class in Astrophysics

Post by mikemarotta »

Through a YouTube channel created by a maths boffin named Tibees, I found this. She misidentified it as a final exam in astrophysics. It is merely plain old astronomy, which, apparently, at MIT is astrophysics.

https://ocw.mit.edu/courses/physics/8-2 ... 2_soln.pdf

Anyway, the course from EFPL covers this material. The EFPL course is only designed to be seven weeks, half a semester or so. And these are 20-35 minutes lectures, not 50 minutes. So, it was not this much in depth. However, most of these topics were touched on by at least one quiz question.

MIT provides similar Open Courseware material.
Introduction to Astronomy
https://ocw.mit.edu/courses/physics/8-2 ... /index.htm
Black Holes and Relativity (Open Courseware)
https://ocw.mit.edu/courses/physics/8-2 ... /index.htm

Physics (All courses)
https://ocw.mit.edu/courses/physics/
Michael E. Marotta
Explore Scientific 102 mm Refractor
National Geographic 70 mm Refractor
Ploessl oculars 40mm to 6mm 2X Barlow
mike49mercury@gmail.com
Cathy Grimes
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Joined: Fri Mar 26, 2021 2:38 pm
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Re: An Online Class in Astrophysics

Post by Cathy Grimes »

This is very interesting.
Even though I am a retired chartered engineer with several hard science degrees, I considered my understanding of physics along with quantum mechanics and particle physics to be not up to the level that I would like it to be. On looking at some Open University courses I found them to be very expensive.
Last week I looked at edX and found some interesting courses on quantum mechanics and similar courses, but they were archived. I looked on the MIT website and found the lecture notes and videos for the same course that was on the edX website. You can find it at:
https://ocw.mit.edu/courses/physics/8-0 ... /index.htm
On reading though some of the lecture notes, I found it to be an accessible course. I will try to complete the course and if I do, I will see about getting a certificate.
mikemarotta
Posts: 107
Joined: Fri Dec 04, 2020 7:04 pm
Location: Austin, Texas, USA
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Re: An Online Class in Astrophysics

Post by mikemarotta »

Cathy Grimes wrote: Sun Apr 11, 2021 11:04 pm "... Even though I am a retired chartered engineer with several hard science degrees,... I will try to complete the course and if I do, I will see about getting a certificate.
Very good. Keep us posted. For myself, I have no actual use for the work. I am not employed in the field. But I feel that it enhances my appreciation of what I am looking at. The stars are pretty at any magnification. If you do not understand what you are observing, you miss the essence of the experience.
Michael E. Marotta
Explore Scientific 102 mm Refractor
National Geographic 70 mm Refractor
Ploessl oculars 40mm to 6mm 2X Barlow
mike49mercury@gmail.com
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