If you liked Stephen Hawking, check out Leonard Susskind's The Black Hole War: My Battle With Stephen Hawking to Make the World Safe for Quantum Mechanics

Made this app for android devices, let me know what you think!

https://play.google.com/store/apps/details?id=com.MKProductions.SolARFree

This is a good place to start: http://www.khanacademy.org/science/cosmology-and-astronomy

And I found this lecture incredibly interesting: http://www.youtube.com/watch?v=7ImvlS8PLIo

Those are the first things that come to mind. I can come up with more later if necessary.

Ah, quasars, the inspiration for my username.

The closest quasars that we've observed are 780 million light years away. The reason they are unusual "nearby" (meaning in recent years) is because they are extremely active galactic nuclei, so matter is actively falling into the central black hole. As the nucleus ages, most of the matter that is going to fall into the supermassive black hole has already fallen in, so yes, it turns into a normal galactic center. I recommend watching this.

Barbara Ryden's 4-part lecture series Introduction to Cosmology, based on her undergrad level textbook. At that site, which is a summer school program, there are also many other good lecture series on cosmology.

As discouraging as it is seeing some of the reactions here, I just don't think the intent of this sub was ever to lay out really complex models in a simple-to-understand, math-light way for general consumption of the curious. I'm going to keep my eyes open for a more layman-friendly cosmology sub and will PM you if I stumble upon one.

Participants here - for better or worse - become frustrated with the wild, off-the-wall theories posted by people who've watched a few episodes of Through the Wormhole and become armchair researchers. The sub name is going to attract a lot of fringe folks, and I'm sure that wears on the regulars.

One book I always recommend to people who are interested in Cosmology, but may not have a lot of formal math background is A User's Guide to the Universe. It presents a wide range of really complex topics in an approachable, intuitive way. You may need to read some sections (like the Special Relativity chapter) a half-dozen times before it really starts to sink in, but it can and will start to make intuitive sense eventually.

It may be metaphysical at this point but it's still worthy of research and hypothesizing about. Max Tegmark has done some great work on the subject classifying and describing the four types of multiverses, the first type is not sci-fi at all. Might be worth reading up on. Here's his book on the topic https://www.amazon.com/Our-Mathematical-Universe-Ultimate-Reality-ebook/dp/B00DXKJ2DA/

I am quite certain that "A Most Incomprehensible Thing" by Peter Collier will be what you are after. I highly recommend it.

What? You mean like Celestia or Sky Map? That's not really cosmology you know.

That's a valid way to look at it. In fact, that explanation was used by Epstein in his book Relativity Visualized

This book is outstanding for understanding relativity without getting too deep in the math of it all.

> I also know a bit of spirituality or what i call it unexplained physics

Be wary of the supernatural -- that stuff is fake. If a claim does not have adequate evidence to support its hypothesis and cannot be peer-reviewed by the scientific community through an academic study or paper, then you should stay away. You should only listen to people who are qualified with a legitimate background in math and physics. This field is filled with so much conspiratorial or fringe bullshit that you need to be really careful about what type of things you are reading or watching.

That being said, a very great starting book for anyone truly interested in cosmology or astrophysics would be Stephen Hawking's <em>A Brief History of Time</em>.

YouTube channels like PBS Spacetime are great, but it's very important that you read books as well. This subject matter can be very complicated and dense and you need to be capable of reading and digesting long-form writing. Books are also really get references that you can highlight, annotate, or refer back to at any time. I personally did not enjoy reading until I was about your age. I picked up some books about space and it changed my life.

Thank you for your opinion.

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The Einstein field equation is exact,

I saw the following in Hans Ohanian's book, &quot;Gravitation and Spacetime&quot;.

In writing the field equation (48) we have assumed that the quantity T^{\mu \nu is the energy-momentum tensor of matter. In order to obtain a linear field equation we have left out the effect of the gravitational field upon itself. Because of this omission, our linear field equation has several (related) defects:

(1) According to (48) matter acts on the gravitational field (changes the fields), but there is no mutual action of gravitational fields on matter; that is, the gravitational field can acquire energy-momentum from matter, but nevertheless the energy-momentum of matter is conserved ({\partial _\nu }{T^{\mu \nu }} = 0). This is an inconsistency.

(2)Gravitational energy does not act as source of gravitation, in contradiction to the principle of equivalence. Thus, although Eq. (48) may be a fair approximation in the equivalence. Thus, although Eq. (48) may be a fair approximation in the case of weak gravitational fields, it cannot be an exact equation.

The obvious way to correct for our sin of omission is to include the energy-momentum tensor of the gravitational field in T^{\mu \nu }. This means that we take for the quantity T^{\mu \nu } the total energy-momentum tensor of matter plus gravitation:

Hey this is an awesome comment, dunno why you got downvoted. Glad to offer some inspiration 🤓

Cool video. If you're a layman physics enthusiast (apologies if a bad assumption) and enjoy consuming qualitative content like this, and liked my comment, you will love this book:

General Relativity: From A to B by Robert Geroch

It gives a masterfully written description of GR in a purely qualitative and intuitive way. There are almost no equations at all, but about 100 figures. Everything is described geometrically. You might even know more about relativity than most cosmologists once you're done :p

It won't give you the ability to do anything formal, but it will open your eyes to the big picture

This is the wrong sub for your question, so it should probably be removed. Before that though, you’d probably enjoy reading The Eyre Affair, where that’s basically the plot.

I find MOND a bit arbitrary and Moffat's MOG (modified GR, aka STVG) more interesting; his papers are up on arxiv but he's also published a pop-sci book Reinventing Gravity. The gist of it is that G and c are not constants at large scale, but fluctuate in their own vector field that holds G/c constant. Can reproduce many results, without dark matter. Although obviously, if you're adding another field, there's now another force to identify, which is rather inconveniently almost impossible to measure at short scales. Fun! [EDIT: link]

Here's a page of some astrophysics/cosmology resource materials The site is a markdown pastebin so the markdown for this page is available and you could directly transfer anything you like into your wiki. To get the markdown, just add '/raw' to the end of the link, as in this: link to markdown of page

I might add some things later, but if I do I'll flag them with the date added so they'll be easily identifiable as separate from this original list.

The faster a particle travels the slower we observe it's time passing. The person moving close to the speed of light experiences time normally, but sees us aging rapidly. We see them barely aging.

If you emit a photon and reabsorb the same photon a minute later it hasn't aged and it's meeting the "future you" form it's point of view

Here are some Time Dilation Calculators:

https://keisan.casio.com/exec/system/1224059993

https://www.omnicalculator.com/physics/time-dilation

Schwarzschild radius question:

If I take a gallon of water and confine it inside a sphere, its diameter will not be 1/2 the diameter of another sphere that contains 2 gallons.

According to this calculator: https://www.omnicalculator.com/physics/schwarzschild-radius

If you have two stars A and B that form black holes, if B is twice As mass, it will have double the schwarzschild-radius. So a star that is 10^12 more massive than a 50 solar mass black hole. Projecting this out, according to wilkipedia the entire visible universe would have a Schwarzschild radius of 13.7billion light years. (implying we are inside a black hole)

If I enter the estimated mass of the milky way * 100 or 200 billion estimated galaxies I get a SR of an even larger diameter.

Is this correct? Does adding mass to a black hole expand the SR so much? Why?

Despite what others are telling you, you can actually run N-body sims on your laptop or home computer. First, read good background material such as this page. You cannot run all N-body codes no your laptop, only those that are inaccurate and grid-based. Specifically, the particle-mesh codes scale as O(N_grid*log(N_grid)), and you can set the number of grid points to be sufficiently low to fit into your computer's memory.

If your advisor isn't helpful, feel free to cold-email people that do this kind of work.

Good luck!

Unfortunately, you cannot get credit at a university by taking a course in the Signature Track https://www.coursera.org/signature/guidebook.

However, there are other reasons why you may want to do the Signature Track. Some of them are listed on the above link

If you're not already familiar with it, I'd include [1804.10047] ΛCDM Cosmology for Astronomers by Condon and Matthews in your reading. A listing of some other resource materials is here.

Not sure if it’s what you are looking for, but this is a good book

Overall I like astro books in this Hot Science series.

I taught a course on undergraduate cosmology, and in the first few lectures I talked about the history of cosmology. I did not know much about the history and while looking around I found the second chapter of this book quite useful:

https://www.amazon.com/Cosmology-Science-Universe-Edward-Harrison/dp/052166148X

Particle physics: https://www.amazon.co.uk/Theory-Almost-Everything-Standard-Triumphs/dp/0452287863/ref=tmm_pap_swatch_0?_encoding=UTF8&amp;qid=&amp;sr=

I know it might feel like this is not the right thread to switch up and share philosophy but I couldn’t resist. The reason I share this book in particular is simple. It’s not philosophical work going against science but strangely but very efficiently trying to reconcile the two. After all, physics and philosophy use to be one and the same at Plato’s time. I think it’s even impossible to separate the two if you want the semblance of a complete answer at the end of any specific scientific problem. At least at the end of any theoretical inquiries and research in science comes the inevitable question of why at all things are the way they are. That’s precisely what separated science from philosophy ‘til this day. Remember the answer to this problem by Feynman: Shut up and calculate. Because of course. Once you start searching for the reason things are the way they are, you get stuck in the ontological maze of explaining things-in-themselves and it’s a bottomless pit. Anyway, this philosophy aims towards modern science in terms of its fondamental motions and ways it incorporate quantum mechanics, general relativity and mathematical theory into its teleology made of a mix between very deep and grave philosopher Hegel and absolute piece of work to understand psychoanalyst Lacan. I got carried out very very fare with this book. In fact, It’s not even over. I’m still processing. It’s simply such a piece of genius synthesis between religion, science, philosophy, psychoanalysis, history with light accents of obscurantism. What a trip. A masterpiece. Now the book:

Slavoj Zižek - Less than Nothing

——>

https://www.amazon.com/Less-Than-Nothing-Dialectical-Materialism/dp/1781681279/ref=mp_s_a_1_1?dchild=1&amp;keywords=less+than+nothing+zizek&amp;qid=1602014916&amp;sprefix=Less+than+nothing&amp;sr=8-1

>It kept math mostly out of the picture, as it mainly addressed the theories themselves

That's a curious perspective.

I'd guess the Brief History, as well.

You should take some introductory courses online and expand your knowledge base. You will feel more comfortable navigating the information with some new skills. There are some terrific courses available from Stanford, MIT and other universities through Coursera and EdX. Perhaps start with "The Evolving Universe" on Coursera.

This is also an excellent overview book. https://www.amazon.ca/Introduction-Cosmology-Barbara-Ryden/dp/0805389121

Yes, IF you get the new second edition by Dodelson and Schmidt, published May 27, 2020. Dodelson's first edition was published in 2003. You can see the considerable changes in the Table of Contents between the two editions on Amazon.

I do not deny that time exists throughout the universe, I say that it it a local phenomenon, not a universal one. Its not the same "time" throughout the universe.

>to say that the concept of "now" is not the same point in time throughout the universe is absurd!

Perhaps it sounds absurd, but it seems to be true nonetheless. Read Professor Carlo Rovelli's book for a pretty detailed discussion of why it's likely true, even though it sounds absurd.

It seems clear these days that there just is no universal concept of "now".

You refer to observers watching black holes consume each other etc. But time for this observer is only a personal construct.

>When I refer to universal time I refer to the way an outside observer sees the progression of events, and there must necessarily be a universal time.

That's not how general relativity works. There is no outside observer or universal time. It's a local and personal phenomenon. It's the difference between Newtonian, and Einsteinian time...

I do seriously recommend Rovelli's books and YouTube videos. He talks a lot exactly this topic from a seriously well informed point of view. I learned a lot...

Cheers!·

Cool book, never heard of it! I also recommend Liddle's book:

https://smile.amazon.com/Introduction-Modern-Cosmology-Andrew-Liddle/dp/1118502140/ref=smi_www_rco2_go_smi_g1405964225?_encoding=UTF8&amp;%2AVersion%2A=1&amp;%2Aentries%2A=0&amp;ie=UTF8

It's very succinct, kind of like a Cliff's Notes. A very handy desk reference, and only uses Newtonian gravity and special relativity except for one appendix. Useful even for advanced students, IMO, for distilling things down to their basics in an easy-to-understand way.

Looks like it's just 200 pages long? Judging from Amazon at least: https://www.amazon.com/Introduction-Modern-Cosmology-Andrew-Liddle/dp/1118502140/ref=sr_1_2?s=books&amp;ie=UTF8&amp;qid=1533220233&amp;sr=1-2

Is that the one? The Oxford "Quick" Reference is even longer: https://www.amazon.com/Oxford-Companion-Cosmology-Quick-Reference/dp/0199560846/ref=sr_1_1?s=books&amp;ie=UTF8&amp;qid=1533220233&amp;sr=1-1

Anyways thanks for the tip, just want to make sure I nail down the right book.

There have been many developments since, but it makes sense to start with the original source material.