Astronomy and Cosmology

Newton stated that each object was attracting each other, but Newton could not answer what caused this attraction. Time passed and the great scientist Sir Albert Einstein solved this problem with his Theory of Relativity. Albert Einstein defined Gravity by the concept of space-time, according to Albert Einstein, gravity is a curve in space-time. You may not have understood this very well and perhaps I cannot explain it to you through this blog, so let's do a little experiment first. You can also take this video if you want As shown in the video, Suppose space-time is not like a fabric on which our planet stars, satellites, etc.…

Does space weather affect the space crafts` launches and do scientists check it before space crafts go to space? I know there is such a fact like space turbulence and it can influence a spacecraft, but can space weather?

Hi, I am new to this so please bare with me. I am currently debating a flat earther, and I am unsure how to answer this question accurately. The claim is that the sun cannot be 93,000,000 miles away, as when you view it from a high altitude, the suns arc changes too much. The conclusion is that this must mean the sun is much closer, otherwise its arc wouldnt appear to change to us. I put this down to perspective and explained that if it were 93 million light years away our position would effect our perspective. (I might be wrong there) But I would also like to know if or why this is the case, I havent observed this or been able to. Thanks if anyone ca…

Many apologies for this OP as I'm sure it has been raised many times before. IFF the universe were truly infinite in spatial extent (and I appreciate the 'unknowability' aspect of this), would this imply perforce that whatever the energy density of the earliest moments of the universe, it too would have been spatially infinite? In such circumstances, would GR predict gravitational effects to be compressive, tensile or ... just undefined.?

https://arxiv.org/ftp/arxiv/papers/1605/1605.09187.pdf The Fermi Paradox is Neither Fermi’s Nor a Paradox: Abstract: The so-called Fermi paradox claims that if technological life existed anywhere else, we would see evidence of its visits to Earth—and since we do not, such life does not exist, or some special explanation is needed. Enrico Fermi, however, never published anything on this topic. On the one occasion he is known to have mentioned it, he asked “where is everybody?”—apparently suggesting that we don’t see extraterrestrials on Earth because interstellar travel may not be feasible, but not suggesting that intelligent extraterrestrial life does not e…

I've seen a number of references to space flowing across a black hole event horizon at the speed of light. If space can be lost in this way, what happens to the vacuum energy associated with that space? i.e. Does it increase the mass of the black hole?

Can you name spacecraft that can be used for microgravity missions and experiments? Nowadays it`s rather popular and useful to use uncrewed guided space vehicles for particular missions.

Two cosmological models involving the universe as never having had a beginning and never having an end (eternal), and having no boundaries (infinite) are really interesting me: The Cyclic universe in which the universe has always been (for an infinite amount of time into the past) and always will (for an infinite time into the future) go through cycles of massive expansion and then contraction. Our Big Bang being the last bounce back from the previous contraction and the cosmic microwave background radiation (CMBR) the result of the rapid expansion from the last epoch. The universe of dynamical equilibrium. The universe is not expanding. Redshift has been misund…

https://phys.org/news/2021-01-mars-chandler.html A combined team of researchers from the Jet Propulsion Laboratory, California Institute of Technology and the Royal Observatory of Belgium, has found evidence that Mars has a Chandler wobble. In their paper published in the journal Geophysical Research Letters, the group describes their study of decades of data from Mars probes and what it showed them. Approximately a century ago, astronomer Seth Carlo Chandler discovered that imperfectly round objects (such as planets) sometimes spin off their axis for periods of time. The phenomenon has come to be known as the Chandler wobble, and has been documented for planet …

I think the smart place to start would be to send out an outer ring of radio satellites into orbit around objects on the outer reaches of the solar system in sequential spherically communicating ring of and radio boosters with an prerecorded pulse system that only signals in Pie numbers so anything picking it up and understood a system of mathematics in our level of understanding would know this was the real thing and they were making first tentative communications with another form of life and all that means in the very understanding of the nature of not only our history our present our future our place in the wild west that is the cosmos and the very nature and origin …

Hello, I recently wrote a paper (which I present here ) suggesting which star has the highest probability of being the source of the WOW! Signal. Do you think that we should reply to the WOW! Signal or not?

Looking at our own plant, every natural element serves a purpose. There is no natural "thing" on our planet (perhaps with the exception of humans) that do not serve a purpose. I imagine the universe should be the same and for the most part it appears so but what is the purpose of lifeless planets? They must serve a purpose in the universe or else they would not exist. They cannot be an "incomplete process".

A UCSB site says, " However, the Earth is actually moving sideways compared to the center of the Sun at 3 km/second...." Normally "sideways" refers to the forward orbital direction, which is at 29.79 km/s, so I am assuming this is the velocity towards the center of the Sun due to gravity, that is offset by the acceleration in a stable orbit. Is that correct? And how does one calculate that sideways velocity for any planet? Thanks.

Isn't there a location in the universe, that everything is moving away from? Sort of an expansion "ground zero"?

It seems very counter intuitive that galaxies should be separating from each other at velocities that are proportionate to distance. But this is what we observe ,it seems. Does this imply that ,at an early stage all the matter that formed those galaxies "talked to each other"? What did they "say"?😉

(Hope this is the right subforum) Really a question about waves,particles and fields wrt electromagnetism. I understand that light propagates as a wave in the Electromagnetic Field and think I am also coming to realise that the Cosmic Microwave Background (CMB) may well be such a field and a primordial one at that. So,this is what I am wondering (and my question) When light propagates through the vacuum as a wave in the EM field can we say that it is propagating through this CMB(field) ? Is the vacuum (in this instance) the CMB field? As a second related question,how does one detect the CMB field if it is the same in al…

Is there any connection between the Cosmic Background Radiation and Dark Matter. Dark Matter apparently accounts for a lot of the overall matter in the Universe.. Should its presence be evident in the analysis of the CBR ? Or would its temperature profile around the time of the BB be indistinguishable from that of ordinary matter? Are there any other ways analyses of the CBR could shed light on the DM mystery?

Scientists theorize that there may be a big subterranean ocean of liquid salt water on Europa, and there is a proposal to send a space probe which could drill down to it. In such an ocean there would be presumably no light, and I don't know if there'd be any CO2 or what temperature the water would be, but by introducing autotrophs from our own oceans would it be possible for explorers to start a food chain, gradually introducing higher species culminating in fish? This would permanently give explorers and settlers something to eat, although they'd have to have chips sent up from Earth. Cheerz GIAN 🙂

I have had this theory for almost a decade and want to get this out there so others can share their opinion on it. Please let me know what you think! The nature of the gravitational properties of antimatter can potentially solve 3 of the big puzzles on physics- dark matter, dark energy, and the lack of observed antimatter in the universe. If antimatter has a repulsive gravitation property, meaning that antimatter is repulsive to all types of matter, including antimatter itself, then it would naturally want to be the farthest away from normal matter- galaxies. The theory is that antimatter is spread out through the intergalactic medium, in between galaxies. …

Stephen Hawking thought an asteroid impact posed the greatest threat to life on Earth. Thanks to <deleted> for sponsoring this video. Any Discussions About This Topic Thread?

Could there be a negative dimension / space And as if it worked and looked

I have noticed that bands on Europa contain smaller intricate wave like patterns. I assume that these "waves" were not created after the widening of the spread, but simultaneously. Could these be caused by gravitational waves emitted from Jupiter? What do you think...

whether there can be opposite of the dimension such as time and space and would it still be a dimension?

Theoretically it is somewhat common for particularly dense neutron stars to form a solid crusts, much like a planet's, with any matter that happens to be around them. At these densities, the neutronium between the crust and the center of mass forms a sort of mineraloid structure (known as "nuclear pasta"). I've been curious as to the chemical properties of this as well as the mechanisms responsible. Does the composition of a neutron star's crust effect the formation of nuclear pasta in any way? For example, would it make a difference if the neutron star formed its crust out of ethane or cyclopropenylidene? What if you threw some magnesium or caesium into the equation? I'm…

Precisely what would happen if, suddenly, 87.5% of a given gaseous planet's mass was somehow transformed into pure oxygen, and immediately after, five small asteroids of pure caesium, each possessing a surface area exactly equal to 5% of the gaseous planet's topographic surface area, collided with the newly oxygenated gaseous planet at the same time at equidistant coordinates? Precisely what would be the effects on the astrochemistry and meteorology of the planet, and how would it effect other nearby astral bodies? It's admittedly a vague question with many variables, so I'll provide some specification; according to what we know about the Solar System, what would be the a…