Astrophysics Definition and 876 Threads

TL;DR Summary: Theoretical astrophysics research status in ISRO, India I am from India and want to be an astrophysicist serving my nation. Whenever I check about any ISRO news, it is always about some engineering achievements, like the launch vehicle and never about pure theoretical research...

Concerning cosmological structures (like galaxies, clusters of galaxies, gas bodies, superclusters...etc) if the elements that make them are close enough they will be attracted towards each other by gravity. Contrarily, if they are sufficiently far apart they will get further away following the...

Spacetime expands at an accelerated rate and the particles with movement associated to this expansion are coupled to the Hubble flow. In many papers that I've read, objects coupled to the Hubble flow are treated as if they have some velocity and kinetic energy associated with it.However, can...

Helloz. I want to become an astrophysicist and was wondering if there topics in math that are HEAVILY used in astrophysics so that I can start focusing on them from early on. I understand that A LOT of different aspects of math are used in almost every field of physics, but I want to know which...

Assuming the Sun’s core has a mass of 0.35 Msolar_mass and taking values for other quantities from a internet background search or from the following figures (i.e.: Radius "solar core" = 0.25 Rsolar_radius ): ------------------------------------------------------------------------...

Summary: Should I major in math, physics, or astrophysics? Hello. I want to be an astrophysics professor someday. Does anyone have experience on whether I should be a math major, or a physics major, or an astrophysics major? And whether I should get B.A or a B.S? Thank you.

Has anyone looked into the details of stellar orbital speeds and required (visible) mass distribution in the Milky Way? Doing some math here - if the local mass density is significantly higher in the inner 10-15% of the galaxy, and then lower and gradually thinning outwards in the disk, we will...

Listen to the following arguments: Earth's orbit isn't perfect ellipse because classically there is the gravitational field of moon and possibly of Mars and Venus which affect it According to general relativity isn't perfect ellipse because there is the curvature of space time which doesn't...

Summary: best publishing sites Hello. I have a theory on astrophysics. I want to find the best free website or platform to publish my articles on it. I want the website to be completely free, not asking for fee from me or the readers in any ways, and not having hidden fees either. please...

My attempt has been attached.

Hi, I'm Dutch, not any kind of Quark ;-) (so excuse me for any bad English) and I'm very curious about "how the universe works". Cosmology/astrophysics and modern physics (quantum, relativity). I find it all mighty intersting. Actually all physics and also how it's all developed and "evolved"...

Many years ago, for my high school senior project, I wrote a solver for the N-body problem that is performance-optimized using the Barnes-Hut algorithm. (the optimization algorithm is not relevant to my question.) In one particular simulation, I simulated a spiral galaxy. The simulation is not...

I was wondering what the best colleges for astronomy/astrophysics are? I'm specifically interested in universities with opportunities for a lot of undergrad research. I've heard good things about University of Colorado Boulder and Michigan State, what's your take and them and what other ones...

I've recently become curious about switching to an astrophysics course for my third and fourth years of undergrad. This course is available to students who have completed two years of either mathematics or physics, and is said to be more mathematically demanding than the standard physics course...

Suppose a light beam is sent from a distant star. When the light beam hit a telescope orbiting around the Earth. How is the light beam modeled? I have searched for many keywords without success. In my opinion, since the beam has gone so far, it can be viewed as parallel rays, with a decaying...

I’ve really been struggling with this book since I started it a couple of days ago. It’s essentially a problem book designed to teach you about astrophysics, structure formation, radiation, fluid dynamics, etc. through a curated set of questions. Some of the questions take a ridiculously long...

Summary:: I'm looking for some great books on deep learning related to image recognition that I can use in astrophysics. Hello, I'm about to start my master thesis, where I, in short, will be comparing snapshots of young binary stars from simulations to observations using deep learning -...

I am not sure where to start for this. Considering it needs to be demonstrate Balmer Break, I am assuming it needs to be wavelength based. As a result I am assuming I cannot use mean (Kramers) Opacity but rather express in terms of Opacity k= n*sigma/rho. My thoughts are to use Boltzmann...

1) If I take as definition of ##a_{lm}## following a normal distribution with mean equal to zero and ##C_\ell=\langle a_{lm}^2 \rangle=\text{Var}(a_{lm})##, and if I have a sum of ##\chi^2##, can I write the 2 lines below (We use ##\stackrel{d}{=}## to denote equality in distribution)...

Dear All. I am an international student who is planning to apply for the Ph.D. in astrophysics in the US in the coming application cycle. I am aiming for the top astrophysics school in the US. For the top, I mean CALTECH, Princeton, MIT, Columba, JHU, Cornell ... e.t.c. I would kindly ask for...

Summary:: You have a spacecraft the size of a cube (2x2x2 m^3, m=3000 kg. It has 24 thrusters (2N each) and one main engine. For preparing your spacecraft for maneuvers, you want to rotate by 180 degrees. For the rotation, you'll use n=4 attitude thrusters per burn. What am I doing wrong...

I'm given an ultra-high energy cosmic ray with energy 10^20 eV. It is coming from a source 10 Mpc away with an extragalactic magnetic field with strength B = 10^-9 G. I am to determine the maximum angular deflection of this cosmic ray, so it hits Earth. I don't have an attempt of the solution...

I'm a physicist familiar with QM, QFT and GR etc but I've never really sat down and learned astrophysics properly. Would Steven Weinberg's new book be considered a good advanced introduction or would people recommend another text. Half tempted to get it anyway to complete the Weinberg collection.

Below the error on photometric galaxy clustering under the form of covariance : $$ \Delta C_{i j}^{A B}(\ell)=\sqrt{\frac{2}{(2 \ell+1) f_{\mathrm{sky}} \Delta \ell}}\left[C_{i j}^{A B}(\ell)+N_{i j}^{A B}(\ell)\right] $$ where ##_{\text {sky }}## is the fraction of surveyed sky and ##A, B##...

I have attempted to link the equations, but I don't really understand how the data given fits. Does the angular radius get plugged in as the deflection angle?

1. Keplers third law (and the asumption that M1+M2 ~ M1) gives that M_Mars = 4*Pi^2*a^3/(G*T^2) With numerical values inserted Mmars = 4*3.14^2*(9400*1000+3396.97*1000)^3/((6.67*10^-11*(7*60*60+39*60)^2) 2. Phobos needs 7h39 minutes to complete a circle, this gives a speed of...

Hi I am a computer science undergraduate working as a data scientist. I generally love studying physics and planetary science. I am aspiring to research in biomarkers and bio signatures in planets. If I have to choose this research path should I study masters in, astrophysics or...

Hello all, I recently did a thought experiment and thought, "what if the universe as a whole is spinning?" This could solve the dark energy problem, as if the universe was spinning, there would be outward pull, and therefore keep the universe expanding. And, I don't know if this means anything...

Summary:: Looking for advice on what Physics topics, which may be dropped, to brush up on whilst studying an Astrophysics focussed degree I'm embarking on an part-time distance learning BSc in Astronomy at UCLAN. I was originally torn between this degree and the BSc Physics at the Open...

In gravitational lensing, the image magnification is defined as the image area over the source area. But many texts also give it as the inverse of the determinant of the jacobian, A, of the of the lens equation. My question is how these are equivalent. The lens equation is...

Hello, I'm struggling with this question A star is observed close to the center of the Milky Way and from its spectrum we find that it is a type A3 star. Its observed magnitude is m_v = 25. There is only a diffusive gas between us and the star, so we can assume an extinction, of 1 magnitude per...

What are some good textbooks for astronomy and astrophysics? I know of fundamental astronomy and the principles of astrophysics. I would prefer it if it were good for self-study. Also, are there any books that are free?

I am taking a class in signal processing. We have a final project in which we seek out "real-world" signal data and process and analyze it, and write a report on what we figured out. I thought it would be interesting to put my own interests into it and try to analyze a pulsar signal. My idea is...

Carbon is considered volatile by planetary science, eg Moon lacks volatiles and thus lacks carbon. However volatiles are defined as "elements or substances with low boiling point", but Carbon boiling point is very high! Its sublimation point is 3900K, so it should be refractory and not volatile...

https://phys.org/news/2020-10-carbon-creation-astrophysics.html Back in 2016 - Recent results in nuclear astrophysics https://arxiv.org/abs/1605.07810 From the abstract -

Riccardo Giacconi (1931-2018) was an italian astrophysicist who was awarded with the Nobel prize in physics back in 2002 for his important contributions to astrophysics. Since he was an astrophysicist he must have heard about the multiverse hypothesis, but I have not found a single paper or...

I'm about to be a senior in the physics program. I can choose General/Special Relativity or Astrophysics. The astrophysics course is not as intensive - the GR/SR course requires mechanics and is more math-savvy. I've been doing some modeling with Lagrangian mechanics for star systems etc. and...

hi! I'm not completely sure what I'm doing but my neighbor sent me this website so i can learn more about what I'm interested in. mostly, I'm interesting in learning about biology, astrophysics/cosmology, and the like. I'm super excited :p

Hi I am planning to do phd in computational astrophysics or planetary science or scientific computing simulation (least preferred in case i am not allowed to the other two). Right now I have bachelors in computer science and planning to do masters in the same. My query is should i join...

Equations I think may be relevant:

Summary:: Which area to best start learning about in Astrophysics. I'm 44 years old and when I was at school we only learned basic things in Maths. Now I'm older, I'm fascinated by the Universe and Astrophysics etc. What would be the best things/areas, maths wise, to learn about first?

Hello all, I'm doing a Master's Degree in Theoretical Astrophysics and now I need to decide in which topic I will do my final project and I wanted to ask you what would be the best option. I would like to do something that would make me have some future in the investigational path I choose...

(If anyone could provide links to information it would be greatly appreciated.) I'm currently taking a class on threats from outer space and have to write a paper on something that could be done in response to an asteroid/meteor coming towards Earth. One of the quickest responses would be to...

Summary:: Need an Astrophysicist from a reputed institute. Can anyone please help me with a Astrophysicist from a reputed institute. I have a paper to present...but don't know how to reachout to a scientist. I tried mailing a few scientists but they don't respond back. Please help. Regards...

The question is taken from An Introduction to Modern Astrophysics by Carroll and Ostlie. I did manage to do the entire question and plot the relevant graphs but I just want to to investigate a bit more. For example I want to look at how the graph would like in the case of the Sun. I don't know...

Hello everyone, I'm a graduated student in astrophysics in Italy. Unfortunately it has been very difficult to find a job that matches my educational background. I am very interested in space science and technology and I wanted to ask if there is anyone who can give me some information about what...

After concluding an investigation about the coriolis effect, I wondered how this phenomenon affected the solar system and in particular the moon. Since the moon is a body that moves within the rotating system formed by the sun and the earth, an apparent deviation in the moon's path would be...

I'm a man. The only thing that I think distinguishes me from the rest is that I am in love with the truth. The truth is very beautiful, that's why I pursue her and when I find her I do nothing but praise her beauty, I love her, I adore her and I am faithful to her. And she, in love with me...

Greetings everyone. I am an undergrad currently majoring in Computer Science with a minor in Physics. I entered college as a physics student because I wanted to pursue astrophysics as a career. After my first 1.5 years of courses and a summer research experience, I concluded that a career in...

I take the following example to explain my question : when a « black-hole » is attracting a planet there is a Force which is proportional to the 2 masses and inversely proportional to the distance between the 2 masses. When the planet moves towards the « black-hole » this attraction force...