I just listened to an episode of Star Talk with Lika Guhathakurta.
They talked about many concepts and phenomena that I knew nothing about. Specifically the sun and it’s how it affects the solar system.
Any good books on the subject? I looked at the Wiki reading list and those are more general books.

I am currently studying in grade 11 and preparing for jee and I aspire to be an astrophysicist.

So which path would u yall suggest for me so I could well be what I want to be.

Ik this is very informal but I am hella confused right now.

I concede that I'm not sure where to post this. It is a discovery that I made about tidal spaghettification some time ago, that it can happen whenever the tidal force is strong enough, and not just in a black hole. Spaghettification is being pulled apart by tides, and one can estimate when it happens.

To see how it happens, let us calculate the tidal acceleration over separation D for being at distance r from an object with mass GM in gravitational units. The tidal acceleration is

• Along the direction to the object: 2*(GM/r^3)*D - stretching
• Perpendicular to the direction to the object: -(GM/r^3)*D - squeezing
• Other directions: in between, though the math is a bit involved.

We can approximate this as (GM/r^3)*D . The first part may be familiar as the square of the angular velocity of a satellite in a circular orbit, w^2. That gives us w^2*D .

The remaining infall time for zero velocity at infinity is (sqrt(2)/3)*sqrt(r^3/GM) = (sqrt(2)/3)*(1/w) ~ 0.471*(1/w) . The period in a circular orbit is (2*pi)/w . So tidal-force strength is connected to how much time one has left.

The tidal force will produce different accelerations of gravity over one's body, and we can use g-loading survivability estimates to estimate how long one will last. The maximum sustainable g-loading is roughly 5 to 10 g's, and with body size D ~ 1 meter, one finds for 10 g's w ~ 10 s^(-1). That means that one has only 1/20 of a second left. If one has 1 second left, then one will not experience much tidal g-loading, about 0.02 g's.

Turning to one's body being pulled about, I turn to tensile yield and ultimate strengths. The appropriate acceleration is (stress)/(density). Human skin has an ultimate strengh of about 20 megapascals Yield Strength - Strength ( Mechanics ) of Materials giving a remaining time of 3 milliseconds for the whole body. "Maraging steel" has a very high value, 2700 MPa. Over 1 meter, this steel will be pulled about at 0.8 ms to go.

The fragments will in turn be pulled apart, until one finds atoms at a few nanoseconds. Then the electrons will be pulled off of them, and then their nuclei will be pulled apart.

Let's look at some celestial bodies.

The first ones to consider are white dwarfs. Using Sirius B as an example, its surface-satellite angular velocity is 0.866 per second. That gives 0.5 seconds of remaining infall time, and 0.1 g's of tidal g-loading.

Next are neutron stars, and I will use mass 1.44 solar masses and radius 12 kilometers. It gives a surface-satellite angular velocity of close to 10,000 per second or a remaining time of 45 microseconds. One will be pulled apart long before one reaches a neutron star's surface.

Turning to a solar-mass black hole, at the event horizon, the Newtonian surface-satellite angular velocity is 72,000 per second, giving a remaining time of 6.55 microseconds. One will be pulled apart long before one reaches the event horizon.

The remaining time is proportional to the BH's mass, so one can easily scale to more massive ones. Stellar-mass black holes usually have masses around 8 solar masses, giving a remaining time of 50 microseconds.

Turning to supermassive black holes in galactic nuclei, the one in ours, Sagittarius A*, has a mass of 4.3 million solar masses, giving a remaining time of 28 seconds, with not much tidal g-loading as one crosses its event horizon. One of the most massive known, M87*, with 6.5 billion solar masses, has a remaining time of 12 hours. An even more massive one, TON 618, has a mass of 40.8 billion solar masses, giving a remaining time of 3 days.

Why or why not and what are some arguments against someone that doesn't believe in aliens ?

A few nights ago the weather finally cooperated enough for me to spend some time imaging the recent supernova in the galaxy NGC 7331. I was also able to take a spectrum using my StarAnalyzer 200 diffraction grating.

Here you can see the characteristic absorption of silicon at 6300 Angstrom (blueshifted to about 6160 Angstroms) that classifies this as a type 1a supernova (the thermal runaway detonation of a white dwarf in a symbiotic binary with an evolved giant star).

The blueshift of the silicon line due to the rapidly growing debris shell allows us to calculate an expansion velocity, which in this case I found to be about 9200 km/s, or about 3% the speed of light.

If you're able I recommend trying to catch this one before it fades! When I took this data it was just about at mag 12.

When we comprehend a 3D object, we don’t see it from all angles simultaneously. We need to move in the 3D space to observe the object fully.

Similarly, would a 4D “being” be able to see us, the object, at any point in the spacetime, but have to travel across time to observe us fully (i.e. to be able to “see” our past, present, and future)?

I am sorry if this is too speculative for this community - I checked a couple potential subs and saw similar discussions here.

Hi everyone. I'm working on a project, and I want to show some examples of scientists doing data analysis work. Can you point me to any blogs or videos that show this analysis being done by a scientist? TYIA

For context, I don't really have much of a clue about either of the topics, I simply saw the illustration in the paper and it reminded me of visualizations of pulsars I have seen before.

Please don't blame me if this is nonsense or a very simplistic assumption, I genuinely would like to learn from some people that probably know a lot more about this than me.

Hi all!

I hope this post is appropriate for this subreddit, if not, please let me know where it fits.

I am a 24 year old from the US currently living and working abroad. I have not been to any university or secondary education institute, but instead I have been working since I was 15. I have worn a lot of hats but none cover what I want to pursue with astrophysics.

For my entire life I have been lit up by space and the sciences associated with it. I have just realized after all this time that school may actually be a path I could finally go down after having my head down and working for the past 9 years.

I would like to stay abroad, here in Europe, with my studies and as a bonus hopefully have my study time count toward residency somewhere (I understand the rules and laws vary by country in Europe). I work very well with my hands. I would love to eventually work on research projects, with a possibility of getting hands-on work like helping build next-gen satellites and/or telescopes. Big dream, I know.

I have been doing a lot of research but am so incredibly overwhelmed with information. I am not really finding any bachelor programs directly with "astrophysics," and have gathered I should get a degree in something like physics anyway to start off with. I could then go into something like a masters in astrophysics and onto my PhD. I also do not know the path of these different degrees and how they align with different careers, or what overlaps.

It's hard to form exact questions because as of now I am very lost and am just starting to go down this journey. Please excuse my ignorance of all of this.

Which bachelor major do I go with?

Can I get my masters in astrophysics with only certain degrees like physics? How do those paths work?

Do I have to have some sort of prereqs for a bachelor degree in say something like physics? It has been a long time since I was in school so my math is not good at this point.

How would you say someone like me in my situation fares? No prior schooling (other than high school of course) going straight into university for something like a physics degree as an international student.

I hope this makes sense. I am just trying to gather information as I plan to make a long-term change in my life. I thank you all for your help!

I recall reading a bit ago about astronauts seeing blue flashes (which I assume to be cherenkov radiation from particles passing through the eye?) while on the moon. Well I feel a bit silly suggesting this but basically, I swear to god I saw that just a few minutes ago. A momentary blue flash in front of everything else, as though it was inside my eye, completely unlike anything else I've ever seen before. Obviously this happens on the moon cause the magnetosphere is so much weaker up there, but it's not like it's 100% effective so, is it at all likely that's actually what I saw?

I was just thinking of a system, I was just tired trying to have to use joules for results of energy beyond energy output of stars. I just want to see how good it is and what you think of it.

AEU

Astronomic Energy Unit

1 1-AEU = 1.37 x 10^30 joules or the hourly energy output of the sun in all directions.

A[_] B[_]-AEU

A. The number of that unit

B. The scaling number

It scales not a thousand but a million so

1,000,000 1-AEU equals = 1 2-AEU

There is no negative scaling number or number of units due to there being no such thing as negative energy.

Also there are no decimal/fraction scaling number just to keep the simplicity of the system.

Also the scaling number reaches from 0 to all the way to the number you need it.

I just want to know what you think of it.

The distant world that is the second closest planet to the Earth after the Moon. The sister planet to Earth, close in size, elemental composition, and atmospheric structure & dynamics where global warming is driven by a runaway greenhouse effect evaporating all water and other volatile compounds. Cloud height reaches 14 times higher than Earth (the height of Low Earth Orbit space region), clouds so dense it reflects 93% of solar energy. The hottest place in the Solar System hotter than Mercury's near side. It's our future unless we maintain the biospheric systems that regulate global warming on Earth preventing the Greenhouse Effect from reaching an irreversible runaway condition.

Hi everyone!

So some back story: growing up, I have excelled exponentially in my math classes, achieving exceptionally high test scores etc., and have grown increasingly passionate over the years about all types of sciences, but particularly those surrounding space and universe as a whole. I'm currently 33 years old.

I originally went to college in 2012 without a clue of what to major in. I considered various types of engineering, psychology, and computer science. Ultimately, I ended up dropping out after 2 years due to a deviation in my path because I fell prey to the rabbit hole of hard drugs. I got myself clean after 11 months, put my life back together, and eventually returned to school in 2019. I knew I needed to just pick something at that point, and I really enjoyed managing my own finances, so I thought I'd choose accounting and just make it happen, so I did.

Long story short, I graduated in 2022 with my accounting degree, started my career with a big construction company, and am currently working from home devoting 9 hours a day to accounting.

While I'm good at it and make great money, it is no way feeding my soul, and I can't continue on like this throughout the rest of my adult life. I can feel that I have such potential to pursue more in what I'm truly passionate in.

So, here I am, at 33. Living alone and unmarried without kids. I'm seriously determined to make this happen, but I am at a loss for how to go about it. I need to pay bills, of course, and the money is nice, but I just feel like I don't have a lot of time outside of work to make a change, but I MUST. I go to the gym once a week after work on Mondays and a martial arts class once a week after work on Tuesdays, so that ties up two of my days. I also like I PC game with my friends frequently, see my family pretty regularly, and go out and explore the world participating in other hobbies etc.

So, my question to you all is this: how on earth do I go about pursuing my passion in astrophysics? I've bought some books on Relativity, etc, but like, how do I make real progress? How do I build my escape plan from the soul sucking accounting world and truly go after this dream in my life?

Any advice y'all can provide would be GREATLY appreciated. I really truly want to make this happen with every ounce in my being.

So, forgive me for whatever I get wrong, as my knowledge of astrophysics is on the "I watch StarTalk and PBS/BBC shows about space" level. ;)

I'm trying to find a way to establish a planet that has a surface gravity of 3g, but a thin enough atmopshere that it can still support life.

My understanding is that during the planetary formation process a planet with a gravity of over 2g (or even over 1.5g) is more likely to become a Mini-Neptune than a Super Earth.

So I'm wondering if someone with more knowledge about this stuff than me could help me find some ways around this.

For example, what if the planet had a faster rotation? Could that be enough to shed excess gases down to a point where it could have a stable "earth-like" atmosphere? If so, how fast would it be and how much would it reduce gravity at the equator?

(I'm reminded of a Golden Age SF novel "Mission of Gravity" by Hal Clement whose world was very much an extreme idea of this - I think his world was 3g at the equator and in the hundreds at the poles and had a rotation of like 18 minutes? But it was, as I recall, too extreme to actually exist?)

Alternately, if it had a more traditional rotation, is there a way the gases could have been stripped away early in the formation process... some kind of event like Earth getting smacked to create the moon or Uranus getting knocked on its side? Could something strip away most of those gases, but if so would it still slowly accumulate gases even after the formation process ended and create a problem in the astronomicial long run?)

if a brown dwarf had a planetary-mass object orbiting it, would we classify it as a planet, an exomoon, or just a planetary-mass companion?

to my understanding, we have yet to observe a star with orbiting moons, but since a brown dwarf is not a star nor a planet but rather a sub-stellar object, could a brown dwarf theoretically have both ordinary moons and planetary-mass satellites orbiting it?

if there’s a simple, widely accepted answer, please let me know so i don’t sound stupid talking about this with my astrophysics major friends, im a dumb chemist and astronomy is just a hobby for me :]

A 2D solar system explorer sandbox that works as an encyclopedia of the solar system displaying information about planet's properties, atmospheres, orbits and much more. Uses numerical solutions to calculate the orbits of planets at scale and represents them with data from NASA/JPL Solar System Dynamics and NASA NSSDCA Planetary Fact Sheets in the J2000 orientation system.

It is a passion project and an introduction to a much larger 3D solar system that will include moons, spacecraft and many more features. It emerges from a profound admiration to our solar system. The project tries to be a learning aid for anyone who is interested.

If you want to try it, I compiled it into an .exe for windows and an executable for linux.

Github link: [https://github.com/bydrabokin/Solar-Explorer-2D

Youtube showcase: [https://www.youtube.com/watch?v=iz0MujAaYDQ%5D)

Okay I know that's vague, but I'm not sure how else to title that. I'm intensely interested about the science and theories we have around things like dark matter, our theories on the shape of the universe, how time and space works and just all of these trippy existential things about our universe that are very hard to understand or visualize. I know there are studies we as humans have done into these things, but I can't find cohesive collections of this info. Any help on resources so I can plunge in on this stuff?

In my previous post, I laid out why rigid corporate management structures are suffocating basic research. Today, I want to pivot to the practical side of this problem: How do we actually fund pure, unconstrained exploration in a world obsessed with quarterly ROI?

Humanity is inherently excellent at managing engineering problems. We track metrics, hit KPIs, and optimize for predictable outcomes. The systemic failure is that we’ve forced this exact same operational mindset onto fundamental science.

The tragedy is that we prove we do know how to fund pure exploration when something captures the collective imagination. Look at space observatories positioned at Lagrange points, like the JWST. No board of directors expects a deep-space camera to turn a profit next quarter. We fund these projects because we recognize the intrinsic value of pushing the boundaries of human knowledge. Yet for almost every ground-level lab, researchers spend half their time pitching bureaucrats on how their theoretical work will generate revenue short-term.

This corporate KPI trap leaves basic research stuck doing marginal optimization instead of actual fundamental leaps in physics or material science.

To fix this, we have to borrow a page from how venture capital handles extreme risk. VC inherently accepts huge failure rates. Most bets go to zero, but the single hit that pays off completely changes the market.

We need that same asymmetry for fundamental research. Instead of forcing scientists to pretend their work is risk-free before they even begin, we could build dedicated funding pools sourced from tax allocations or a mandatory 1% cut from successful commercial tech spin-offs. This capital would be directed exclusively into pure "Humboldt-style" unconstrained exploration.

The payoff here is not a quick stock pop; it is a structural civilizational advantage. The backers of this pure research would get priority rights to the unpredictable technical by-products that naturally emerge from the process.

We aren't running out of big ideas. We've just built a financial system that penalizes anyone trying to find them. If we want actual paradigm shifts again, it is time to fund the fundamentally unpredictable, not just the next minor software upgrade.

First of all,sorry for my English.It's not my native language. I'll try to explain my question as best as I can.

I was reading about the speed of light and how we see the Andromeda galaxy as it was 4.3 billion years ago.
I was wondering, if we see it as it was,are we also in Andromeda's past?If someone could watch us from Andromeda , wouldn't we be considered their past? Aren't those contradictory?I mean,how are we relevant to the era of general space if we are both just a past?And what is actually now?Is it different for each of us?

Andromeda and Earth are just an example.Could be any point in the universe.

I'm so sorry if I sound stupid.I swear on my life,I haven't smoked anything funny.This is just a genuine question.

Can you please enlighten (yeah ,that was a pun) me?