Dark Matter in the Milky Way and Beyond

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Күн бұрын

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This is part of my complete intro Astronomy class that I taught at Willam Paterson University and CUNY Hunter. If you want to watch all the videos in the correct order, please visit my website at www.jasonkendall.com
Dark matter is a great mystery. It has mass but doesn't interact with light at all. So how do we know it exists? Watch!
Supplement the videos with "OpenStax Astronomy"
openstax.org/books/astronomy/...
25 The Milky Way Galaxy
0:00 Introduction
0:01 The Link to Newton's Gravity
4:41 Circular Motion due to a Central Force
6:16 Circular Motion due to Gravity
7:16 Measuring Rotation Speed of Galaxies
8:54 The Rotation of the Galaxy's Disk
13:30 The Mass of the Milky Way Galaxy
16:56 Example: Milky Way
19:56 Dark Matter in the Milky Way
21:43 Rotation Curves of Other Galaxies
23:20 23% is Dark Matter
26:38 The Dark Matter of the Milky Way Galaxy
30:31 Dark Matter Halos
31:27 Dark Matter in Galaxy Clusters
38:45 The Musket Ball Cluster
42:43 REVIEW QUESTIONS

Пікірлер: 16

@LuciFeric137 4 жыл бұрын

Very interesting. Thank you professor.

@JustaReadingguy 4 жыл бұрын

Wow great stuff.

@elijaguy 2 жыл бұрын

27:13 NOBOKs. (nobody knows' s )

@butHomeisNowhere___ 4 жыл бұрын

Am I correct in saying that, given the data, it looks like the dark matter density increases with the distance from the nucleus? Sort of like how a mattress will lift up around your body when you lay on it, the dark matter increases *around* baryonic matter?

@JasonKendallAstronomer 4 жыл бұрын

Not quite. Dark matter is distributed much more evenly. It’s “hot” dynamically, and it has a hard time losing energy of motion (kinetic energy) because it doesn’t interact with light (electromagnetic interaction). Therefore it stays spread out and the density doesn’t drop off as fast as the regions which emit light.

@elijaguy 2 жыл бұрын

I wonder why Zwicky didnt call it transparent matter. Dark interacts with light: it absorbs it. therefore it becomes dark, therefore it is opaque. While Dunkles Materie is invisible, absolutely transparent, and this quality is what haunts the scientists and also us, the laymen.

@JasonKendallAstronomer 2 жыл бұрын

I always thought it could've ben namd "Doesn't Matter" or auf Deutche "Matter Nicht".

@elijaguy 2 жыл бұрын

@@JasonKendallAstronomer LOL you are funny!

@christopherreed2694 Жыл бұрын

Not all of us with dyslexic learning disorder I put a lot of time into listening to you your very smart 😉 I thank you for speeding up my learning rather than learn 🙂 something not followed

@book3100 Жыл бұрын

I don't have the math, yet, but doesn't dark matter smell a little bit like luminiferous aether?

@JasonKendallAstronomer Жыл бұрын

Can’t you smell that smell? Skynyrd likely knew something about luminiferous aether.

@book3100 Жыл бұрын

@@JasonKendallAstronomer lol, I suppose so. 😆👍 I'm learning. It's just hard to take some things as given. Which is why I'm trying to learn the math at this later stage. I gotta know, ya know? Thanks Prof, for being here.

@JasonKendallAstronomer Жыл бұрын

You’ll want to get this book. An Introduction to Modern Astrophysics a.co/d/ilgFNDq

@HotPinkst17 4 жыл бұрын

Stellar black holes are hard to directly detect, couldn't dark matter just be a mix of all the hard to detect objects in greater than expected quantity? If our tech can't 'see' it then it must be dark matter doesn't seem like a scientific explanation for making the extraordinary claim of a new substance all that strongly.

@pensiring7112 4 жыл бұрын

Is far as i know, the number of black holes required would be fare too large. But there is always the possibility that there is not excess mass, but some flaw in our calculations.

@JasonKendallAstronomer 4 жыл бұрын

Those are called MACHOs and searches have been done. They do exist, but they are not in great enough amounts to account for the missing mass.