Astronomy and Cosmology

I want to start off by saying I am not a scientist, I hold no PhDs, and have published no papers. all of my understanding of the universe is from pure fascination and an un-healthy level of desire to understand how the universe works. with that said, I was recently reading up on the newest JWST images that could potentially show that the theories on how we believe the universe started and how its expanding my be wrong, or at the very least even more incomplete than we previously thought. If the universe is assumed to be expanding, then as galaxies move further away, they would be distorted by an optical illusion that would make them appear larger the further a…

The US astronomer and astrophysicist Frank Drake (1930-2022) has passed away aged 92. Born in Chicago Illinois, he trained at Cornell, and then in graduate school at Harvard, specialising in radio astronomy. He worked at the National Radio Astronomy Observatory in Green Bank West Virginia, and at the Jet propulsion Laboratory Pasadena California. Drake became one of the founders of the SETI program (search for extraterrestrial intelligence) and is best known for writing the Arecibo message sent to the globular cluster M13 in 1974, and also for creating the famous Drake Equation in 1961 which sets out to estimate the likely number of communicative extraterrestrial ci…

The big bang theory is very vague, it doesn't explain how the matter was created to cause the big bang you would need energy but where did the energy come from. lets say this universe is a simulation, the universe that created our universe how was that universe created or is their a god but what created the god? in science matter cant be created by nothing it requires energy.

Alright, for starter i’m just a guy who is curious about some aspects of science. I completely agree with the way scientist describe gravity but I’d like to build some familiarity with terms used and names of scientist and names of theories to correct or add to my understanding of gravity. I’ll explain my level of how I visualize it even though it doesn’t completely consider every. This is just how i visualize it to understand the actual theory. Ok so to begin the way I imagine gravity working vs the way its described to me. The way I imagine gravity working is sort of like oil and water in the sense that matter and space aren’t the same thing you can’t mix them toge…

hello, i'm a beginner we are not able to look inside a black hole, could we see out of it if we were inside ? when we try to look at the past of the big bang, would we be trying to look at the outside of a black hole from the inside ? what do you think of about this ? Are there any theories evoking this hypothesis?

This is easy for you... Looking north, the stars rise above horizon on east and set below horizon on west. I think. How to locate the north with the 'North star' if everything is moving ? Or everything revolves counterclockwise (at northern hemisphere) in a circle around the 'North star' , appearing as the pivot to all other stars motion ?

I have learned that the rate at which the galaxies are receding from each other is accelerating. (Quite the surprise when this was discovered ,I seem to recall) So we have an ongoing acceleration of the recessionary process. Is there any way to quantify this acceleration and so determine whether this acceleration itself is constant or whether it could be slowing down ?(or even speeding up) I think the mathematical term is "jerk" Could the jerk be negative and how could we know?

Does the size vs the density of a planet have an effect on the extensiveness of the atmosphere? More specifically would an earth sized planet with 2x earths gravity have a more or less extensive atmosphere than a planet 2x the size of the earth with 2x the gravity of earth or a planet 2.5 times the size of the earth with 2x the gravity?

I've posted this before, but I still believe that the future of humans away from the Earth is in space stations, not planets or moons. Once you get them up to a certain size, you can rotate them and create 1g of artificial gravity, you have virtually limitless free energy beaming at you, and you can land and take off using practically no fuel whatsoever. You can mine the moons for raw materials, you can use the cheap solar electricity to manufacture everything, you have free cold storage, and space is well and truly limitless. Here on Earth, we are running out of space with seven billion humans. Up there, there is room for seven billion billion humans, without stepp…

https://theconversation.com/dark-matter-our-review-suggests-its-time-to-ditch-it-in-favour-of-a-new-theory-of-gravity-186344 So, the question is: Is Mond good enough to gain consensus favor?

I've been confused about how red shift works. If I understand correctly when we look far out into the cosmos stars that are farther away are more red shifted. My question is... Does the red shift predominately come from the stars speed moving away from us, or does the light also red shift as it moves through an expanding universe? I.E. a combination of both factors. Given that it's said the expansion of the universe is accelerating, you would think that the further away you look (i.e. father back in time) that the red shift would be less. That is if the red shift entirely occurs when the light leaves the star. If the red shift also occurs as the light travels to…

Compared to the size of the Earth the sun is massive but there are stars out there that would reach out to the orbit of Jupiter if they were where our sun is. I read that when our star reached a certain size it started fusion at the core and then stopped growing because it will start to blow all the gases away that it was feeding on. Most stars are born in a cloud of gas and dust that can be light years across so there's no end of material to feed on while growing. With that in mind what determines how small or large a star will become during its birth?

It is said that the universe is 13.7 billion years old because we have seen light from an exploding star that took place 13.7 billion light years from earth, and it is also said that 13.7 billion years ago the universe was smaller than an atom, so how on earth could anything have been 13.7 billion light years apart? Some scientist say that 13.7 billion light years is the limit of what our technology can see and interpret and that we don't really know the true age of the universe. Isn't giving the universe an age based on the limit of our technology the same thing as standing on a beach back in 1300 AD, looking out on the horizon and saying the earth is flat because that's…

Hey! Check out this video: an absurd search for dark matter! Link below. url deleted

If I choose a galaxy near the edge of the observable universe, and I send a ray of light toward this galaxy, will the light ever reach the galaxy?

Here is article link: https://arxiv.org/abs/2205.04623 So, what do you think about that ?

hello I would like to know the complete formula to have a precise value of the value of the acceleration of the expansion of the universe (m/s^2) at the Hubble radius in the Lambda-CDM model please ...if possible with an arXiv source, which would be a luxury thanks in advance

If there is a redshift of light in the universe because of distance, then galaxies that move away with constant velocity seem to move away with acceleration. So there is no need for bigbang-theory?

Does anyone know whether the whole ‘syzygy’ thing in the lore of the Destiny series is actually scientifically plausible? Basically, the idea is that that the species that would become the Hive lived on a water giant (the lore calls it a gas giant, but I’m almost certain that was just a goof) called Fundament with a huge number of moons, and they learned that at some point all the planets moons would align, and their combined gravity would produce a massive tidal bulge that would be abruptly released once they moved out of alignment. Producing what basically amounts to an apocalyptic mega tsunami. I’m very skeptical that this could happen as described, but I’m just curiou…

At what point in the future before the heat death of the universe (which I believe will be in 10¹⁰⁰ years' time) will it become impossible for any sort of biological life anywhere in the universe to continue? Will it be when all the stars have burnt out or what? Cheerz GIAN 🙂

Please delete this post $\frac{1}{3}$ [tex]\frac{1}{3} [/tex] [tex]\frac{1}{R}(\frac{{{d^2}R}}{{d{t^2}}}) = - (\frac{{4\pi G}}{3})(\rho + 3P)[/tex]

I got curious and wondered how much weight we lose while a solar eclipse is in effect so I calculated it here are my calculations please correct me if I'm wrong/made mistakes; Earth's g=9.81N/Kg Moon's gravitational pull acting on a man standing at the surface of the earth = ((6.67x^-11)x(7.35x10^22))/(384.4x10^6)^2 where 6.67x10^-11 is the gravitational constant, 7.35x10^22 is the mass of the moon, 384.4x10^6 is the distance from the moon to earth therefore moon's g on us is 3.318x10^-5 N/Kg. Now the sun; ((6.67x10^-11)x(1.989x10^30))/(149.6x10^9)^2 therefore sun's g on us = 5.928x10^-3N/Kg. so 9.81/9.81+(3.318x10^-5)+(5.928x10^-3) = 0.999393 so x100 = 99.94% o…

I see that it is said the telescope will not just sit at L2 but will be in orbit around it. I don't understand how this works, as I gather that L2 is at a "peak", rather than a"hollow", in the gravitational field due to the Sun/Earth system, with the result that objects at L2 will drift away from it (rolling down the slope, as it were), unless artificially returned to it at intervals. If this is right, how can the telescope orbit L2? Can someone explain?

Why do we assume we're in a normal place in the universe, when we're on a planet in a solar system in a galaxy that supports life? Isn't the vast majority of the universe the space between things? Why is it we ignore the small scales when concluding the universe is isotropic and homogeneous. When anything that is applied to is true. A billard ball is apparently more uneven than the planet earth when enlarged to the same scale. Isn't a typical place in the universe somewhere in a void between galaxies. Isn't it also a place in the extreme distant future?

Hi, Here is my question, until now, I thought "of course, it's impossible". The matter will never be hard enough to resist, and the whole thing is in meta stable equilibrium anyway : any deviation would pull the closest sides of the sphere and break the whole thing. ("That's dumb !.") Until I thought about this : what about solar wind and matter production from the star...? It seems to me now, that if you really close the star into a solid sphere, it will still produce a powerful solar wind, and temperature and pressure that would fill the solid sphere, until it increase enough to push the sphere away. So here is my question : is a "self pressured" Dyson sphe…