Astronomy and Cosmology

I am thinking most people here are familiar with this event. I think about it sometimes and I have wondered about alternate theories. Is it possible that Oumuamua was not necessarily accelerating away from us under it's own power but the Solar System is accelerating along its flight path due to some other force or early event? I don't offer any explanation as to why the solar system is accelerating in this scenario. I just wonder if it is mathematically possible. If the solar is system were accelerating at some rate, could the behavior of Oumuamua be explained?

Hi @ all! I'm an interested layman with some background - mostly popular science books and TV shows, and Phil Plait's Bad Astronomy blog. Reading about the just-published gravitational wave observation results made me revisit some old thoughts about neutron stars, and what would happen if and when... (1) two of pass each other closely on hyperbolic trajectories? (1a) have a less close pass? Would there be a - kind of - critical distance they'd have to keep? (1b) could / does the acceleration on the inbound branch make one collapse further and form a black hole (due to relativistic mass dilation) (2) one neutron star does such a pass on anothe…

Hello everybody, I'm sorry for bothering you,but I joined here for one single question and clarification. I would like to know how can I calculate Moon's brightness and correct calculation of it with result if possible? I'm terrible in math and calculations and one guy told me result that is impossible,but I don't get how did he got that result? Here is his calculation: Intensity 1/int 2= (distance 2)^2/(distance 1)^2. 1lux/int 2=0,001^2/384400^2=147 billion lux per 1m of Moon's surface. Can you explain me what did he do wrong and what is the real calculation for it as well as final result since this is obviously impossible. I read that …

I'm wondering if it would be theoretically possible to give a huge boost to the solar sail principle, by using tuned mirrors? Imagine the craft with the solar sail, reflecting the Sun's photons back towards the Sun, and being propelled as a result. What if you positioned a massive object, with a mirror, directly opposite your required direction of travel. The mirror is tuned to reflect the light accurately back at the solar sail. And the solar sail reflects it back to the mirror. And the light ends up going back and forth until its lost almost all of it's energy. So instead of using the light just once, it's used possibly thousands of times, and instead of extr…

Found this article............. https://phys.org/news/2021-11-expansion-universe-impacts-black-hole.html New study proposes expansion of the universe directly impacts black hole growth: the paper here.... https://iopscience.iop.org/article/10.3847/2041-8213/ac2fad :::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::: My question is why isn't any BH gravitationally decoupled from the large scale expansion rate, in the same way our solar system/galaxy /local group is also decoupled from the large scale expansion rate? Or am I missing something? Yes I understand that th…

Do you think it will ever be possible to travel faster than the speed of light? I love to get excited about us discovering life on another planet and potentially being able to communicate with them, but with the vast size of the universe, given our current understanding of light travel, surely this will never happen? Even our closest known 'Earth like planet' is some 1,000 lights year away, so even a radio signal would take a thousand years to get there and then another thousand years for any return message (assuming there is a civilisation there capable of detecting radio waves), so it seems kind of pointless?

The orbit of the ISS space station is defined by the following parameters (data as of 07/11/2021) : - - Perygeum 419 km above sea level, - Apogeum 421 km above sea level, - - Orbital period 91,34 minutes (91min 20 sec). From the above data, it follows that the ISS is moving in orbit at a speed of 7786,3 m/s. According to the standard calculations for the mean orbit altitude = 420 km and gravity g = G*M /R^2, - where M is the mass of the Earth = 5,9736E+24 kg, - and the orbit r…

Question: I understand that close-in planets in a red-dwarf system are probably tidally locked. However, if the planet had a large moon, would the tidal locking be avoided? Would the tug of the moon keep the planet from being locked? Thanks.

The recent and ongoing eruption of a Volcano on the Island of La-Palma in the Canary Islands is causing a huge amount of damage and destruction. While so far thankfully no lives have yet been lost, I,m unable to find much news in relation to the famous telescopes on that Island. https://phys.org/news/2021-09-toxic-gas-rivers-molten-lava.html extract: "The rivers of lava, up to six meters (nearly 20 feet) high, rolled down hillsides, burning and crushing everything in their path, as they gradually closed in on the island's more densely populated coast. One was bearing down on Todoque, where more than 1,000 people live, and where emergency services were preparing…

The author of this article points to 17 unresolved problems in GRT http://sergf.ru/litgen.htm He believes that these problems can be solved within the framework of the LITG but using the GRT metric. In LITG, gravity is a force. The above features of general relativity show that most of problems of theory of gravitation may be removed by use of LITG with the idea of using a metric similar to metric of general relativity, as a first approximation to a more accurate theory of gravitational field. In this case, general relativity becomes an extension of special relativity and has its function in the case when the results of spacetime measurements are dependent on ex…

I was watching John Michael Godier and he said that a possible technosignature that could indicate alien life would be a star that had an unnatural composition. I know the heaviest element a star can fuse naturally is iron but scientists have discovered Przybylski’s star which contains traces of plutonium. I personally think it’s NOT a technosignature and I am thinking of writing a story and I was wondering what element would never exist in a natural star and would have to be created artificially. Does anyone know what that element could be?

NASA sent perseverance to mars in a supposedly dried up lake to find fossils. Although they are not expecting to find large dinosaur bones that we have on earth, they are looking for any evidence of microbe life. although the question are their fossils on mars is still unanswered, we should keep our hopes up on finding past life on another planet.

Do we know many metals are in the outer solar system? eg the gas giants, Pluto, their moons and the Kuiper belt? Or can someone point to some easily intelligible layman's literature. I'm thinking that if human beings were living there, they'd need to mine metals to make their own stuff. Cheerz GIAN 🙂

Hi, at the beginning of time there was roughly equal amounts of matter and antimatter, however the matter seems to have won it over the antimatter. why is this , why was there either more matter than antimatter , or if equal what property would have the matter win over the antimatter ? thanks

Hi. This morning I called up YouTube and browsed the multitude of videos for something interesting to watch (let's face it, television isn't that interesting). I often select science programs, some of which are excellent, though one should always exercise a critical attitude. But one video I saw discussed the size of the universe (multiverse?) and brought up the concept of a moebius topology to the cosmos (look it up if you don't know what that's about) So there's a possibility that we could in theory travel back to where we started but reversed? That made me think. Is antimatter simply matter that has moved (expanded?) to such an extent that it has travelled through…

I am not a physicist, and the physics I have studies in colleges, are only physics applicable to civil engineering course (mid-80s) and computer science course (late 90s), so nothing in regards to astrophysics. what are differences M-theory and Multiverse? If they are different, which is likely to be true?

I have two yes/no questions:
 Would an observer, from any random galaxy in the entire universe…
 1. measure the exact same temperature of the CMBR? 2. observe the same quasars that we observe, and qualify them as quasars as well? 1. yes/no 2. yes/no

Thought this pretty cool creation someone posted over on the Space Subreddit. https://www.reddit.com/r/space/comments/ooexmd/i_unwrapped_buzz_aldrins_visor_to_a_360_sphere_to/

The sun will get 10% brighter, all water will be gone. The dying sun with become a red giant and grow in size to the point where it will consume the earth. This the common prediction of our future, the end of us. But do you believe that the end of our story has already been written in stone? I don't...what I believe is there will be a line of great scientists in the future that will make us look like cavemen 🙂. Here's the thing, they haven't been born yet. Maybe not for several, dozens of generations from now. Heck, their families are probably living in huts right now 🙂. They could reverse engineer the sun, they could ignite a NEW one. They co…

I was thinking about spacetime today. Looking at the beginning of time (and space) we are not sure how it started. Some theorys suggest that the big bang happened from a single point called singularity, others that it happened everywhere at the same time. If it happened at a single point and is expanding, there needs to be an end of space (and time) in the form we know them today. So what happens if we reach that point? Can we just leave and come back like you would leave your house or do we enter another (kind of) world that existed before the big bang? If so, is the spacetime only some sort of a layer of a bigger structure or is it lying on some sort of infinite void? A…

Can someone explain to me the connection between equations of Einstein and Friedmann, please? And how they are relevant to the cosmology?

TL:DR Your mind will be blown. Bioreactor/diesel blows Solar out of the water. Bioreactor is approximately 5x more efficient than Solar Panels optimized for Mars. WITHOUT additional efficiency modifiers that can be applied to Bioreactors. Same area of flat bioreactor as Solar Farm (50km^2) = power for 277 astronauts. Bioreactor makes rocket fuel (solar panels do not). Bioreactor is modular and can be built on Earth and shipped to Mars. Bioreactor uses in-situ materials, solar panels cannot. Bioreactor recycles all its nutrients/m…

Does all of space go on for eternity? is it still being created? does space ever end? This has been in my head for over 5 years now and i still don't know the answer.

the prevailing theory among cosmologists is that the observable universe began from a point of singularity and this singularity rapidly expanded in all directions to the present universe we see today. We are, to use the anology, in a balloon expanding outwards in all directions. We have detected the Microwave Background Radiation in equal distance in all points of directions. This observation proves one of three things, that our solar system is the very center of the universe (and therefore the point of origin) or the instruments are inaccurate, or astronomers are not interpreting the data correctly. Astrophysicists state that before the big bang, there was no vacuum…