The Astronomy Thread

Tholan

Tholan

Blackwing Lair Raider
951
1,834
Damn, I missed that. Got some pretty lousy reddish pictures last year using my smartphone, but it was cool nonetheless —
especially considering I spent $5k to go to northern Norway for some northern light sightseeing, and it was cloudy the entire time.
 
Gravel

Gravel

Mr. Poopybutthole
42,281
145,973
Captain Suave said:
Click to expand...

This whole derail makes me feel retarded. Physics was never really my thing.

But watching this video, the one question I have is if all of that is true, how does anything travel at the speed of light? If we're breaking this down to how fast atoms are traveling, what difference does it make if we're talking a space ship or the various particles making up "light?" The conclusion for that video is it takes infinite energy to get to 1c, and so it's not feasible. So how the fuck does c exist? It sounds like a theoretical limit that you can approach but never hit, which means light doesn't travel at the speed of light.

Then, for me, it also raises the question of us "seeing" the stuff in the universe. Unless it's moving in a direct plane towards us (which, since we're moving, would be impossible), it would be moving infinitely away from us, relatively. That star 5000 light years away would be moving in an infinite direction away from us, where every second we're staring at it, it's moved away billions of years.
 
Gravel

Gravel

Mr. Poopybutthole
42,281
145,973
Aldarion said:
You can't think of any differences between the particles that make up ships and the "particles" that make up light?
Click to expand...
I mean, watch the video? His example is a photon clock on a spaceship. The photon is really what I'm referencing as far as "spaceship." The photon can never reach the speed of light, because it requires infinite energy in order to do so. It can approach it but never hit it.

And what is light if not photons. If the photon in the photon clock can't hit the speed of light, why can the photons in light do it?

Like I said, my eyes glazed over most of this derail. If it's a super obvious answer, explain it to me, cause that was my conclusion from the video that seemed to be a glaring hole.
 
ShakyJake

ShakyJake

<Donor>
8,181
20,525
Gravel said:
I mean, watch the video? His example is a photon clock on a spaceship. The photon is really what I'm referencing as far as "spaceship." The photon can never reach the speed of light, because it requires infinite energy in order to do so. It can approach it but never hit it.

And what is light if not photons. If the photon in the photon clock can't hit the speed of light, why can the photons in light do it?

Like I said, my eyes glazed over most of this derail. If it's a super obvious answer, explain it to me, cause that was my conclusion from the video that seemed to be a glaring hole.
Click to expand...
Photons are created already traveling at 'c'. They aren't accelerating to c at any point.
 
  • 1Like
Reactions: 1 user
Captain Suave

Captain Suave

Caesar si viveret, ad remum dareris.
5,754
9,871
Gravel said:
This whole derail makes me feel retarded. Physics was never really my thing.

But watching this video, the one question I have is if all of that is true, how does anything travel at the speed of light? If we're breaking this down to how fast atoms are traveling, what difference does it make if we're talking a space ship or the various particles making up "light?" The conclusion for that video is it takes infinite energy to get to 1c, and so it's not feasible. So how the fuck does c exist? It sounds like a theoretical limit that you can approach but never hit, which means light doesn't travel at the speed of light.

Then, for me, it also raises the question of us "seeing" the stuff in the universe. Unless it's moving in a direct plane towards us (which, since we're moving, would be impossible), it would be moving infinitely away from us, relatively. That star 5000 light years away would be moving in an infinite direction away from us, where every second we're staring at it, it's moved away billions of years.
Click to expand...
Photons have no mass. Massless things always travel at c. We know the value of c because that's how fast we measure photons traveling.

As far as "why c?", I don't think there is an answer within the realm of science. Physics is observational. That's just how the universe is.
 
Last edited:
  • 3Like
Reactions: 2 users
Furry

Furry

Email Loading Please Wait
<Gold Donor>
23,956
32,476
Captain Suave said:
Photons have no mass. Massless things always travel at c. We know the value of c because that's how fast we measure photons traveling.

As far as "why c?", I don't think there is an answer within the realm of science. Physics is observational. That's just how the universe is.
Click to expand...
Yet we observed that photons have measurable mass. That fact is rather inconvenient, so we made some math loopty loops to explain how that can happen, because space itself is actually the force, and photons are innocent.

Observations are often fitted to our convenient design we expect for reality. A good summary of theoretical approaches to studying this and the implications of photons with mass.


There's plenty of gaps in our understanding of photos. One of the most easily explainable is that photos are a lateral wave to some degree. Which means information in the lateral inherently moves faster than c, despite this being theoretically impossible. The idea behind quantum entanglement is essentially exploiting this lateral movement to the extreme.

Personally, I think our understanding of photons is just very weak, and QE is just bunk, but there's lots of experimentation into photons that merits pursuit.
 
Captain Suave

Captain Suave

Caesar si viveret, ad remum dareris.
5,754
9,871
Furry said:
Yet we observed that photons have measurable mass.
Click to expand...

No we don't. Experiments produce mass values where the uncertainty range includes zero and non-zero values, and as experiments continue to grow in precision over time the bounds on that uncertainty increasingly ratchets down closer to zero. Given that all experiments will have error, it's impossible to experimentally exclude non-zero values.

That paper just discusses what would be true if the mass were non-zero, but very explicitly does not claim that it is non-zero.
 
Last edited:
  • 1Like
Reactions: 1 user
Captain Suave

Captain Suave

Caesar si viveret, ad remum dareris.
5,754
9,871
Furry said:
That's precisely what I presented the paper as.

Why do you insist on ignoring context all the time.
Click to expand...

Sorry, it seemed to me that the paper link was connected to your first paragraph. I'm not willfully ignoring context; message boards aren't a perfect medium for communication. A simple "that's not what I meant" is fine, no reason for ascribing ill intent. I'm happy to own my misreading. My bad.
 
  • 1Like
Reactions: 1 user
ShakyJake

ShakyJake

<Donor>
8,181
20,525
I had an interesting "discussion" with ChatGPT (o3 'thinking' model), in which I asked whether it would be possible to create a simulated reality that allows for Star Trek-like interstellar travel, while keeping the laws of physics largely consistent with our own and avoiding any use of "magic" to achieve superluminal speeds.

It responded with some modifications to physical constants that would permit such a universe to exist, yet still feel indistinguishable from our own reality.

I'm not sure whether what it proposed actually makes sense, but it was an interesting thought experiment.

Here's the gobbledygook it came up with:

Concise profile of the “warp-enabled” universe


  • Baseline physics: Standard quantum mechanics, electromagnetism, and Newton–Einstein gravity hold wherever the χ-field equals 1, so everyday chemistry, engineering, and biology behave as in our world.
  • Two extra ingredients
    1. Refractive spacetime field χ(x): Sets the local signal speed ceff=c0/χc_{\text{eff}} = c_0/χ. Engineering a thin χ-shell around a vessel creates a warp bubble that can move at coordinate speeds vs≫c0v_s \gg c_0 while occupants remain locally sub-luminal.
    2. Universal clock T(x): A scalar “master time” labels every event, eliminating closed-timelike curves but introducing a tiny, direction-dependent anisotropy in high-precision timing and light-speed measurements.
  • Observable departures from our universe
    • Femtosecond-scale clock drifts and Michelson-Morley–type phase shifts reveal a preferred rest frame.
    • Light bends and slows in high-χ regions, giving the cosmos a weak “refractive” large-scale structure.
    • Warp bubbles crossing χ-gradients emit brief shock flashes; exotic matter quotas also allow stable wormholes and negative-mass scaffolds.
  • Energy economics of FTL
    • Total warp energy Ewarp∝β2R2ΔRE_{\text{warp}} \propto \beta^2 R^{2}\Delta R (β = ship speed / c₀).
    • Planet-to-orbit hops (β ≈ 3, R ≈ 30 m) cost ~10¹⁴ J—comparable to modern chemical launch energy.
    • Interstellar liners (β ≈ 50, R ≈ 200 m) require ~10¹⁸ J—within a mature fusion economy.
    • Only megacivilisations can bankroll β ≈ 100 “galaxy-hop” craft.
  • Civilisational implications
    • Navigation charts list both position and χ-index; plotting courses resembles optical ray-tracing.
    • Interstellar data moves mainly by courier bubbles; conventional radio remains limited by local ceffc_{\text{eff}}.
    • An absolute notion of “now” simplifies coordination and precludes time-travel paradoxes.
  • Existential status
    • This configuration is internally consistent and, in a multiverse framework, lies in a narrow but non-zero slice of life-permitting parameter space.

In essence, it is a universe almost indistinguishable from ours at human scales, yet equipped with a tunable speed-of-light field and a master timeline—making routine faster-than-light travel energetically demanding but technologically attainable.
Click to expand...
 
  • 1WTF
  • 1Like
Reactions: 1 users
Ukerric

Ukerric

Bearded Ape
<Silver Donator>
8,518
10,758
Gravel said:
This whole derail makes me feel retarded. Physics was never really my thing.

But watching this video, the one question I have is if all of that is true, how does anything travel at the speed of light?
Click to expand...
Only things without mass can travel at the speed of light, and by a quirk of the math, they also cannot travel below the speed of the light.
 
Furry

Furry

Email Loading Please Wait
<Gold Donor>
23,956
32,476
Chanur

Chanur

Shit Posting Professional
<Aristocrat╭ರ_•́>
30,951
52,251


??? Galaxies like this are expected to be dim and ancient but this is bright and seems newish. Suggests it makes stars much faster than we expected and is nitrogen dense.

It also suggested our universe could be inside a black hole and that the big bang was actually us falling into the black hole. Then there might be other universes outside the black hole?

I other words we might not know shit about fuck.
 
Last edited:
Furry

Furry

Email Loading Please Wait
<Gold Donor>
23,956
32,476
Chanur said:


??? Galaxies like this are expected to be dim and ancient but this is bright and seems newish. Suggests it makes stars much faster than we expected and is nitrogen dense.

It also suggested our universe could be inside a black hole and that the big bang was actually us falling into the black hole. Then there might be other universes outside the black hole?

I other words we might not know shit about fuck.
Click to expand...

This is one of the galaxies I was thinking about when I said the big bang theory is moving closer to being observationally excluded as we develop better tools some months back. There's plenty of stuff that just doesn't fit with a big bang universe we see now, but none of that evidence is nearly as poignant as how far our most distant observations of galaxies diverge from what the big bang predicts or can even allow for.
 
You must log in or register to reply here.