Astronomy and Cosmology

How exactly does the expansion of space result in the lengthening of the wavelength of a photon? So you have a tiny photon in superposition with regards to its position and momentum travelling through spacetime for 13 billion years. An excitation propagating through the EM quantum field. Presumably the field is stretched by expansion, but the photon at any moment is a point. So how do the properties of the photon get stretched when it is just a point in the field? Unless the photon isnt a point, and is a line? And if it is a line, then space expansion doesnt occur at any instant but rather over a period? If a volume experiences space expansion, how do you measur…

Astrophysicists unveil biggest-ever 3D map of Universe: The map is very isotropic and homogeneous, the large scale galactic filaments are not as apparent on this scale. Discussion? Isotropic: .(of an object or substance) having a physical property which has the same value when measured in different directions. .(of a property or phenomenon) not varying in magnitude according to the direction of measurement. Homogeneous: .of uniform structure or composition throughout. Reference: https://www.ctvnews.ca/sci-tech/astrophysicists-unveil-biggest-ever-3d-map-of-universe-1.5030682

A hypothesis is proposed to explain the anomalous clustering of the orbits of trans-Neptunian objects (TNOs) by the comet-like orbit of Planet 9 with an aphelion of ~500 AU and a semi-major axis of ~250 AU. Passing through the Kuiper Belt, Planet 9 chaotically interacts with TNOs, leading to alignment, anti-alignment, and scattering and a decrease in the period of their orbits. But at the same time, alignment creates a closer interaction, which ultimately accelerates scattering. Thus, TNOs whose arguments of perihelion as a result of scattering are grouped in an area at ~180° opposite to Planet 9 have more stable orbits due to a shorter interaction time. And the most stab…

A deep field view from Webb, just click on the link in the article and zoom in and out, the small screen bottom right tells you where you are. You can also adjust filters. https://phys.org/news/2025-06-largest-universe-revealing-ghttps://cosmos2025.iap.fr/fitsmap.htmlalaxies-early.html Link here if you prefer not to read the article. https://cosmos2025.iap.fr/fitsmap.html

I've annotated this diagram by Dr Ralph Lorenz about the hydrological cycle on Titan. Does it look right? CHEERZ, GIAN🙂XXX (science age; 12)

I have wondered, if the reason gravity doesn't work at the quantum scale, is bc the shape of spacetime at that scale, is essentially flat/shapeless.

Hello, I'm new to this forum and eager to discuss a preprint paper I recently uploaded to ResearchGate. The paper, titled Fractal Topology of Spacetime, explores a scalar cyclic model and is approximately 17 pages long with a word count of around 7,000. Since it has not yet undergone peer review, I would appreciate any insights or constructive feedback. Would it be appropriate to share the full text here, or would posting a link to the paper be preferable?

I am about to start general astronomy at my college, any suggestions on what to prepare for or any tips regarding the subject?

ok.. someone help me understand this some scientists state some light the detect is from just after the bigbang, and has taken around 13 billion light years to reach us i understand that, but surely that light must have hit something inbetween?

This is something I can't figure out. Why don't they add a module that has a big centrifuge so the astronauts can work in 1G gravity? Or at least they can sleep and recreate in 1G. The ISS is like a big tinker toy where modules of all shapes and sizes can be attached. Why not attach such a centrifuge?

Hiya , I am new here and have been considering shapes . Recently I considered the Suns shape and its apparent roundness . I then considered movement of the Sun and thought to myself if it was moving then how can it retain being a round shape . My question to you all is, If the Sun was moving , wouldn't the shape not be round ?

Are you aware if the apparent superluminal velocities observed with relativistic jets from quasars is a settled issue as being caused by the angle of observation? I have heard that this explanation is disputed, but that was some time ago. Is it settled now?

although i have no idea what this potential stellar engine might look like, i do have a reason to believe we can harness energy from black holes (and subsequently use said energy) using stellar engines. ways of gathering energy from black holes include hawking radiation and accretion disks. i call this potential megastructure a nihility propulsor. thoughts? could this work in theory?

Why is blue shift not called violet shift? I never got the reason, I realize it's possible that there is no reason other then it's easier to say, but I would love a solid answer. Red and violet are at opposite ends of the visible light spectrum, it would make sense to call it violet shift instead of blue shift. Now here's where you make me feel like an idiot because I'm worrying about such a trivial thing.

The Jeans instability is the collapse of a cloud of gas or dust. Recently, a vSauce short claimed that if you wanted to destroy the Sun, you would need to spread its material far enough that it wouldn't recollapse into a star again. vSauce gives the number at 10 AU (Astronomical units) I usually trust vSauce but I have no clue how he got this number and I can't find any additional sources supporting it. Is 10 AU correct? Jeans instability - Wikipedia How To Destroy The Sun

We know that the Earth is protected by a magnetic field that channels dangerous solar wind to the poles, causing the Aurora Borealis. But what about the magnetic poles where this solar wind is impacting the Earth? Is it dangerous for people or animals to spend an extended period of time at the poles, because of the channeled radiation? I asked ChatGPT this question, and here is the answer. Is ChatGPT wrong? "The Earth's magnetic field does channel the solar wind — a stream of charged particles emitted by the Sun — toward the polar regions, leading to phenomena like the auroras (Aurora Borealis and Aurora Australis). However, this …

Just reading an artcle about a black hole ripping a star apart due to its gravity. https://scitechdaily.com/black-hole-tears-star-to-shreds-unleashing-cosmic-shockwaves/ Seems interesting, however I just wondered if this is a similar phenomenon that is mentioned in the Brian Cox series recently on BBC one where he mentions asteroids around planets also being pulled apart and forming rings. As with the paper above, this new disk is also interacting with another star, I think Professor cox talks about Phobos is going to one day break up, some parts will burn up, however the rest will form a ring or rings around Mars. So something similar is also happenin…

Can you help verify this theory?Continuous Gravitational Influence Theory.pdf

It finally emerged from behind the trees in my front yard (I had to stand at the very end of my driveway to see it) photo with hand-held iPhone

I read this article stating that I have access to the original article but I didn't understand how they measured everything and if this new finding would reduce the need of dark matter. Searching "dark matter" in the article I found:

It has been suggested by a learned Doctor (no name given) that large amounts of electrons and protons in the solar wind enter the Earth propelled by the planet’s magnetic field so that Earth’s mass increases over 100’s of millions of years. I find this difficult to believe. However, can it be estimated just how much mass over, say the last 200 million years could have been added or subtracted from the Earth by solar emissions (CMEs, solar wind etc.)?

Hello, When I think about the expansion of the universe, and how it appears to be accelerating, I understand that the expansion of the universe is more than just galaxies moving apart at greater and greater speeds but space itself expanding at an accelerated rate. But if space is expanding at an accelerated rate, does that mean time is also expanding at an accelerated rate? Or speeding up? Space and time are, after all, part of one continuum called "spacetime", are they not? If so, what does that entail?

The new telescope is stirring up a lot of controversy, we are seeing objects at distances that defy logic. The truth of the beginning will never be known unless we can detect the very last and most distant galaxies out there. Will we ever have an instrument that can detect the true edge of the universe? More and more theories are coming to light regarding the time of the beginning and the course. We live in a new age but we always have and if we always do we may never find the answers we are searching for.

The FLRW metric is often described using the symbol \(\chi\). It occurred to me that many of our viewers would not recognize this angle. The metric can be expressed as a 3d hypersphere for its spatial part \[dl^2=R^2(d\chi^2+sin^2\chi d\phi^2\] the 3d hyper sphere is an embedding in 4d space using (x,y,z,w) in the following manner below For some reason trying to insert images messes up latex instructions in the above but in this case its still readable. anyways the above is from the following reference https://jila.colorado.edu/~ajsh/astr3740_14/flrw.pdf see section 10.1 I am considering adding this diagram to the pinn…

You may have heard that the origin of the Moon was due to a small planetary body colliding with the Earth. I believe that this theory is correct and the biggest evidence of this is on the surface of the Moon. We all can see the large dark areas covering the near side of the Moon called Maria, these are very large lava beds that fill very large craters. The Maria filled these craters due to the very deep and intense impacts that created them. The Maria craters are the largest and newest of all the big impacts to occur on the surface of the Moon. Over 90% of the Marias are on the Earth facing side of the Moon, and it is this fact that brings my atte…