What are /r/astrophysics' favorite Products & Services?

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I know how you feel, I've been there, hold tight, it gets better, once out of high-school, everything changes.

http://www.academicearth.org/courses/introduction-to-astrophysics/ One of my favorites when I was in high-school

Space: Ten Things You Should Know by Dr Becky Smethurst

https://www.amazon.co.uk/Space-Things-You-Should-Know/dp/1841883824/ref=mp_s_a_1_1?dchild=1&keywords=becky+smethurst&qid=1627049454&sr=8-1

She’s an astrophysicist at Oxford. She also has a YouTube channel and she does a podcast for The Royal Astronomical Society. Check them out.

We have emission or absorption lines from certain elements. Eg one of the main lines is hydrogen at wavelength 656 nm. This is in the red part of visible light. We do this measurement, so we know if we're moving at the same velocity as the source of this emission/absorptionb line, then 656 nm is where we will see it.

https://chem.libretexts.org/Courses/Solano_Community_College/Chem_160/Chapter_07%3A_Atomic_Structure_and_Periodicity/7.03_The_Atomic_Spectrum_of_Hydrogen

If on the other hand if the object was moving away from us then we will see that line at, say, 700 nm, or anything greater than 656 nm. Hence a red shift, since longer wavelength is on the red side of the spectrum and we say the same even if the line goes into the infrared or microwave or radio.

Similarly if we measure this at a wavelength shorter than 656 nm then it is blue shifted.

From these measurements we can determine a value called z, the red(blue)shift value calculated as
> z = (observed wavelength - laboratory wavelength) / laboratory wavelength

If z < 0 then we say it is blueshifted, if z > 0 then it is redshifted.

https://www.omnicalculator.com/physics/redshift

The largest redshift observed is the Cosmic Microwave Background with a value of z = 1089.

The concept you are circling is called a "frame of reference." Things feel normal within your frame of reference. No matter what the rate of time passage, a person will always feel time passing "normally." So a person on Miller's planet will feel time passing normally, even though time passes at a much slower rate than on Earth. A clock brought to Miller's planet will appear to function normally for people on that planet, but to a distant observer (someone with a sci-fi level telescope for example), would see the clock moving incredibly slowly.

If you want to deep dive into the physics, I highly recommend The Science of Interstellar, by Kip Thorne. He's the world renowned theoretical physicist that dreamt up this movie and then consulted on the script, resulting in multiple scientific papers being published. He's also a very nice guy and responded to an email I sent him. :) https://www.amazon.com/Science-Interstellar-Kip-Thorne-ebook-dp-B00NUB4EVC/dp/B00NUB4EVC/ref=mt_other?_encoding=UTF8&amp;me=&amp;qid=1608419979

Gravity is still an interaction described by a field theory and you can try to quantize the fields occurring in it (so they become operators that satisfy some commutator relation) and see what you get. Tldr it's not that easy to do in tried and tested ways

http://www.scholarpedia.org/article/Quantum_gravity_as_a_low_energy_effective_field_theory

Don't get hung up on "it's not a force, it's curvature of spacetime!"

You could buy him a class on something like The Great Courses. There are some fairly inexpensive ones. In the same vein, but for free, you could look for virtual (since going online they've been all ages) Astronomy on Tap events and make an evening of it.

Hi, I'm currently an undergraduate at Caltech studying astrophysics. I also went to public high school and didn't get a wonderfully amazing education. I just want to tell you that you can succeed, so long as you have sufficient drive and motivation.

Your education is what you make of it. If you think your education at school is inadequate, you should supplement it with self-study (I wish I did this in high school). I recommend learning some computer programming (Python is a good place to start). You could also consider reading the Feynman Lectures; its one of the best introductions to physics out there.

Finally, you should talk to people in the astronomy department of local universities to get an idea of the type of research people do in the field. It is also not too uncommon to get involved in astronomy & astrophysics research in high school, particularly as a junior or senior.

I'm also glad to answer any questions you have (to the best of my ability)

It's mainly from the Doppler Effect. Article explaining it: https://io9.gizmodo.com/the-truth-behind-interstellars-scientifically-accurate-1686120318

I'd also recommend Kip Thorne's The Science of Interstellar. He gets into the details a lot deeper.

Reading this should be basic research: Ringworld: The Graphic Novel, Part One (Ringworld: The Graphic Novel, 1) https://www.amazon.com/dp/0765324628/ref=cm_sw_r_apa_i_S3C89Q8XCW2PB4K8A84T_0

Scifi is built in part on previous scifi. Ignore the classics at your own peril.

You are correct as far as I remember. The fact that gravitational force is directed directly towards the sun results in Kepler’s law about same areas in same time, and together with 1/r^2 it results in elliptic, hyperbolic orbits. Circular orbit is just a special elliptic orbit. Feynman once reconstructed Newtons argument as described in the book “Feynman’s lost lecture” (https://www.amazon.com/Feynmans-Lost-Lecture-Goodstein-1-May-1997/dp/B012HUA5IM/ref=sr_1_2?crid=3JXO7P0VG9BCE&amp;keywords=feynman+lost+lecture&amp;qid=1663046789&amp;sprefix=Feynman%E2%80%99s+lost%2Caps%2C174&amp;sr=8-2)

There are some nice applications in the book "Numerical Python in Astronomy and Astrophysics" by Schmidt and Volschow.

>&gt; Should I take Computer Science to go into astrdeparentphysics?

NO!

A long time ago in the galaxy milky way, I majored in both Astronomy and CS. A'Hearn was young and bouncy and full of EXCITEMENT then. But I was too stupid to do real math, so I dropped my astronomy major -- yet I was the CS dept valedictorian. (I was graduated against my will by mom, who caught me taking grad school classes without bothering to graduate.

See, "easy A" classes like topology and group theory and predicate calculus aren't REAL math.

I was graduated against my will by mom who caught me taking grad school classes without bothering to graduate. But any mathematician will point out that computer science "math:"

• ​ No fractions
• No negative numbers
• You only have to know how to count up to 1

That's not math; THIS is math!

Sure light isn't technically a particle but I took some creative liberty!
You can download it here: https://play.google.com/store/apps/details?id=com.UpsilonStudios.Photogenesis

The music is an electrified version of Carl Off's O Fortuna.
In celebration of a successful sunshield deployment!!

I really recommend this book: https://www.amazon.com/Applied-Computational-Physics-Joseph-Boudreau/dp/0198708645/

It's all C++ and mostly about computational physics in general but there are a couple of chapters that are related to astrophysics (N-body simulations etc.).

It's quite expensive but I'm sure you can find it somewhere online/in a library.

Here's an even more in depth interactive version. It goes from things as small as a quark, to the furthest we can physically see do to the light past that point not reaching us yet.

If you are after something a bit more than wikipedia, there is scholarpedia, articles are peer reviewed. http://www.scholarpedia.org/article/Black_hole you can start there and go down the rabbit hole on your favourite aspect, GR, accretion, etc

Otherwise, i would advise a ARAA article: https://www.annualreviews.org/doi/abs/10.1146/annurev-astro-082708-101811 there are few others, but if you want to start on the interaction of supermassive black hole in galaxy evolution, this is a solid reference.

The most successful theory of gravity is general relativity which has been around for 100 years now. It makes very accurate predictions that have been tested and confirmed in experiments repeatedly over the last 100 years. Beyond that you can calculate some quantum corrections to GR.

Hobson / Efstathiou is a good textbook on general relativity.

I think I would advise you to try to learn a lower-level language like C/C++ next to keeping your python knowledge up to date. Python is flexible and versatile (like Perl) so it's great for trying out new ideas and scripts and exploring data and making plots etc. Big simulations will in general not be done in python, but more probably in C, C++ or FORTRAN (like MESA or NBODYx), so knowing a bit of those types of languages will be useful. type

You should also familiarize yourself with some basic Linux things like SSH and Tmux/Screen since any serious calculations shouldn't be done on your personal machine.

Websites like https://www.hackerrank.com/ provide some courses on these topics

Another solid one is this book. But it is on the "cheaper" end. https://www.amazon.com/Astrophysics-People-Hurry-deGrasse-Tyson/dp/0393609391/ref=sr\_1\_4?keywords=neil+degrasse+tyson+astrophysics&amp;qid=1638372444&amp;sr=8-4

The entropy of black hole is hidden from the observer outside the event horizon...when a mass with entropy enters the event horizon the loss in entropy on sight is compensated by the increase in entropy of the black hole. http://www.scholarpedia.org/article/Bekenstein-Hawking_entropy Look at this link for blackhole entropy

Also, let me recommend two excellent books on the subject of Time:

• The Order of Time, Carlo Rivelli, 2018
• From Eternity to Here, Sean Carroll, 2009

These are two very approachable books for non-physicists that deal with time from a physics perspective. I recommend them highly.

If basic math and physics doesn't scare you, my astrophysics bible (covering MANY topics) is Carroll & Ostlie: An introduction to modern astrophysics.
Apparently it is crazy expensive on Amazon. I remember paying much less for a new edition...

This person might inspire you (and might also be worth dropping an email to): https://smile.amazon.co.uk/Astronomers-Tale-Bricklayers-Guide-Galaxy/dp/1780895550/ref=sr_1_1?dchild=1&amp;keywords=Gary+fildes&amp;qid=1620823437&amp;sr=8-1

Astrophysics for People in a Hurry

Not exactly what you're looking for, but is an incredibly good book for its price.

I’d also recommend Space: 10 Things You Should Know by Dr Becky Smethurst

https://www.amazon.co.uk/Space-Things-You-Should-Know/dp/1841883824

She’s an astrophysicist working at Oxford University and has a great YouTube channel and podcast too

If you would like to learn more on this topic, I would recommend the book big bang - the origin of the universe by simon singh. It was the book my high school physics teacher had me read and within it is the best explanation of special relativity I have ever come across. Along with the history of our discovery of the big bang as the origin of the universe, which is also a great story.

The Big Orange Book by Carroll and Ostlie and Introduction to Cosmology by Ryden should cover everything you need for an undergraduate overview of astrophysics. Both are standard works so you should be able to find a second hand copy for very little. If you know how to use google or library genesis you should also be able to get an ebook pdf version if you prefer that.

It's arted and soundtracked by yours truly. That's an electronic version Danse Macabre you're hearing in the background. The goal is to get to the most massive star possible.

Here's the link!

https://play.google.com/store/apps/details?id=com.UpsilonStudios.Nucleogenesis

If it is for hobby purposes I would just see what subjects you find interesting. For most subjects there are nice books. Which aspect of astrophysics would you like to know more about? Stars, galaxies, cosmology, planets, solar system etc... If you want to know more about everything I would recommend an introduction text book like https://www.amazon.com/Astronomy-Physical-Perspective-Marc-Kutner-ebook/dp/B00IE6MRJE

If you want to read some great books on astrophysics and quantum physics, I recommend the books written by Professors Brian Cox and Jeff Forshaw: Universal and The Quantum Universe

They are brilliant books and deliberately shy away from using any complex mathematics, explaining in detail all of the maths that is used.

If you wanna go into the math, you could pick up BOB.

50 Physics Ideas You Really Need to Know. I read it for the first time when I was about your age and definitely was an inspiration for me to then go onto studying physics at university. Really well written and helps people at any level understand more about the world around us.