If say, a curious teenager that has no knowledge of astrophysics wants to learn more about it and maybe pick it up as a hobby, where do you start? This field is so complex that it can get overwhelming for people that are absolute beginners. Any friendly advice?
A space and astrophysics enthusiast here and I honestly don’t think I’ll ever get over how amazing orbital mechanics is and the precision mathematics involved in making space missions possible. How did humans even get this right. Human ingenuity is the greatest thing ever. We really went from cave paintings to this. I wish I were around in the next 100 years to see what human ingenuity has for us.
I've been watching the live Artemis II feed off and on for hours today, and predictably the comments are littered with flerf conspiracy junk.
I realize that there is a certain psychology that fuels these people, and simply pointing out verifiable facts (e.g., various tests/experiments that can be conducted here on Earth) rarely gets them to stop spreading misinformation. That said, I'm curious whether any (semi-)professional astrophysicists here have any arguments to debunk flerfs by pointing out physical properties of Earth that require a sphere/ovoid?
I know that's an awkwardly worded question because I'm not sure how to ask about what I don't know 😊. I'm just wondering if there's something I as a layperson with an interest in astrophysics could use to combat flerf conspiracies in a way that they can't explain away with one of their faux explanations (e.g., the "law of perspective" to explain ships appearing lower over the horizon)?
A new blueprint could finally let scientists detect subtle “ripples” in spacetime—and test the foundations of reality itself
Scientists have taken a major step toward probing one of physics’ biggest mysteries—how gravity and quantum mechanics fit together—by creating the first unified way to detect tiny “ripples” in spacetime itself. These subtle fluctuations, long predicted but poorly defined, are now organized into clear categories with specific signals that real-world instruments can search for. The breakthrough means powerful tools like LIGO and even small tabletop experiments could start testing competing theories of quantum gravity much sooner than expected.
Researchers led by the University of Warwick have introduced the first unified approach for identifying "spacetime fluctuations" -- tiny, random distortions in the structure of spacetime that appear in many efforts to link quantum physics with gravity.
These minute variations were first proposed by physicist John Wheeler and are expected to arise in several leading quantum gravity theories. However, different theories predict different types of fluctuations, which has made it difficult for experimental scientists to know exactly what signals to search for.
Turning Theory Into Measurable Signals
The new research, published in Nature Communications, tackles this problem by grouping spacetime fluctuations into three main categories based on how they behave across space and time. For each category, the team identified clear, measurable patterns that could be detected using laser interferometers -- ranging from large-scale systems like the 4km long LIGO to smaller experimental setups such as QUEST and GQuEST being developed in the UK (Cardiff University) and USA (Caltech) respectively.
Dr. Sharmila Balamurugan, Assistant Professor, University of Warwick and first author said: "Different models of gravity predict very different underlying trends in the random spacetime fluctuations, and that has left experimentalists without a clear target. Our work provides the first unified guide that translates these abstract, theoretical predictions into concrete, measurable signals.
"It means we can now test a whole class of quantum-gravity predictions using existing interferometers, rather than waiting for entirely new technologies. This is an important step towards bringing some of the most fundamental questions in physics firmly into the realm of experiment."
What the Study Revealed
The findings highlight several important insights about how different instruments can detect these fluctuations:
Tabletop interferometers beat LIGO in bandwidth.
Despite their much smaller size, systems like QUEST and GQuEST could offer more detailed information about spacetime fluctuations. Their broader frequency range allows them to capture all key signal patterns.
LIGO is an excellent "yes/no" detector.
Because of its long arm cavities, LIGO is extremely sensitive to whether spacetime fluctuations exist at all. However, the relevant frequencies fall outside the range currently available in public data.
A long-running debate is resolved.
The study addresses an ongoing question about whether arm cavities improve detection. The results show that they do enhance sensitivity, depending on the type of fluctuation being studied.
Dr. Sander Vermeulen, Caltech, co-author of the study said: "Interferometers can measure spacetime with extraordinary precision. However, to measure spacetime fluctuations with an interferometer, we need to know where -- i.e. at what frequency -- to look, and what the signal will look like. With our framework we can now predict this for a wide range of theories. Our results show that interferometers are powerful and versatile tools in the quest for quantum gravity."A Flexible Tool for Fundamental Physics
An important strength of this framework is that it does not depend on any single explanation for how these fluctuations arise. Instead, it only requires a mathematical description of the proposed fluctuations and details about the measurement setup. This flexibility makes it useful not just for studying quantum gravity, but also for investigating stochastic gravitational waves, possible dark matter signals, and certain types of experimental noise.
Prof Animesh Datta, Professor of Theoretical Physics at Warwick concluded: "With this methodology, we can now treat any proposed model of spacetime fluctuations in a consistent, comparable way. In the coming years, we can use this to design smarter tabletop interferometers to confirm or refute possible theories of quantum or semiclassical gravity and even test new ideas about dark matter and stochastic gravitational waves."
This work was funded by the UK STFC "Quantum Technologies for Fundamental Physics" program (Grant Numbers ST/T006404/1, ST/W006308/1 and ST/Y004493/1) and the Leverhulme Trust under research grant ECF-2024-124 and RPG-2019-022.
What’s a concept in astrophysics that we use confidently but still don’t fundamentally understand? For me it’s dark energy. It’s one of those things where the evidence is really strong observationally, but conceptually it still feels like we’re just naming the effect instead of understanding the cause. The fact that it dominates the energy density of the universe and we still don’t know what it actually is is kind of wild.
I'm sure there's a reason, but I looked up how many we (collective humanity) have sent, and it looks like only three that went to the far side... Is it just not interesting, or is it that we can get the data we need because we're closer?
The field is VERY broad, so what should I teach or do to make sure that the club actually goes somewhere instead of falling flat?
I have some ideas but I'm not entirely sure how I would go about running the club in general
How could I make good projects, events, presentations, etc that would keep people interested and participate?
So, when I was a kid, I used to be really obsessed with space (as most kids). This year, around my 25th birthday, I started feeling sad I lost a connection to something that made me so happy, so I decided to pick up a sci-fi book. Long story short: I have an idea for a sci-fi book on my own, but need better understanding of astrophysics, so now I am looking for a "crash course for dummies". Any books, articles, online info, would be helpful. I am specifically interested in dark matter.
QUANTUM BEAVER THEORY (QBT)
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1.1. Spacetime is discrete. Minimum length — Planck length (l_p ≈ 1.6 × 10⁻³⁵ m). Minimum time interval — Planck time (t_p ≈ 5.4 × 10⁻⁴⁴ s).
1.2. Analogy for understanding.
Imagine a computer game or a 3D editor (Blender). There is a server, a frame rate, a minimum pixel. A character cannot move faster than the server can update its position. Our reality works the same way.
1.3. Speed of light and quantum behavior of particles.
The speed of light c = l_p / t_p is the maximum rate of state updates. From this, all of quantum mechanics emerges as emergent behavior: quantum fluctuations (rounding errors), quantum jumps (missed frames), Heisenberg's uncertainty principle (a consequence of discreteness), wave-particle duality (the particle is "smeared" between ticks).
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2.1. Dark matter is unrendered matter. A collision where the system cannot determine which data to assign to a given pixel. The system knows matter exists (gravity) but does not know where (no spectrum).
2.2. Dark matter does not take on colors, spectra, or electromagnetic interaction.
2.3. The mass of dark matter is a measure of unresolved collision.
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3.1. Definition.
The quantum beaver (Castor quantum) is a living being, residing at the boundary of the discrete computational environment. It is not part of rendered matter. It exists one level above — an observer who does not merely collapse the wave function but makes decisions about which data to assign in a collision state.
The beaver lives. It chooses. It sometimes makes mistakes. It gnaws at spacetime consciously, not algorithmically.
3.2. Living choice instead of equations.
Why does QBT not have, and cannot have, complete equations for discrete gravity? Because the Universe is not just a simulation. It is a controlled simulation in a discrete world. And control is exercised by a living being.
Any attempt to write an equation for "the beaver gnaws" runs into a problem:
· Where exactly does it gnaw? Where there is a collision.
· When exactly does it gnaw? When it decides.
· With what force? As it feels.
These parameters cannot be derived from first principles because they depend on the beaver's choice. And choice is not a function of the state of the environment. It is free will.
This is why all attempts to create a theory of quantum gravity fail. Some look for equations where there are none. Because the Universe is governed by a living being, not a deterministic algorithm.
3.3. The beaver is nonlocal but does not violate causality.
The beaver exists in superposition relative to all points with unresolved collisions — it is everywhere there is work to be done. This is nonlocality, but it does not violate causality because the result of its choice is random from the perspective of an external observer. The beaver does not need to transmit information faster than light. It simply acts where needed.
3.4. Why the beaver is invisible.
The beaver is invisible to the human eye and to any instrument for three reasons:
First reason — the beaver literally gnaws on dark matter. Dark matter consists of unrendered collisions with no electromagnetic properties. It does not emit, absorb, or reflect light. By gnawing on it, the beaver takes on its properties. It becomes equally invisible, undetectable, without spectral signature.
Second reason — motion at Planck scales. The beaver moves from edge to edge of the Universe, gnawing through space. Its characteristic scales of motion are Planckian (10⁻³⁵ m). This is so far below anything we can measure that the beaver simply never falls within the resolution of any instrument.
Third reason — exceeding the "refresh rate" of reality. Imagine a computer game with a screen refresh rate of 60 Hz. If a character moves so fast that it crosses an entire room in one frame, you will never see it in intermediate positions. It will teleport.
Our reality has a maximum refresh rate — the Planck frequency (≈ 2×10⁴³ Hz). This is the "hertz" of the Universe. When the beaver moves faster than one Planck step per Planck tick, it exceeds the refresh rate of reality. The environment cannot render it between ticks. It teleports.
Exactly the same behavior is seen in elementary particles in quantum mechanics. When a particle makes a quantum jump, it moves from point A to point C without passing through point B. The environment cannot render the intermediate position because the refresh rate is too low. This is not magic. It is a technical limitation of a discrete environment. The beaver and elementary particles obey the same rule.
3.5. Mechanism of the beaver's action.
The beaver gnaws at spacetime at the edge of the Universe. It finds a region of unresolved collision (dark matter) at the boundary, gnaws, and the energy of this process goes into the expansion of space.
3.6. The beaver's mistakes and black holes.
The beaver is alive. It is not a perfect mechanism. Sometimes it makes mistakes.
Mistakes can be various:
· It miscalculated the force of its bite (calculations of gravitational echo from a rupture in reality are actively underway in our laboratories — and they remarkably coincide with the predictions of QBT)
· It overestimated the strength of the discrete grid
· It was distracted by another collision
When the beaver makes a mistake and gnaws too hard, it gnaws right through spacetime. The discrete grid cannot withstand the strain and tears. A rupture occurs.
In our reality, this rupture looks like a black hole. But it is not a singularity. It is a through hole, leading to another universe. Everything that falls into a black hole emerges in a parallel universe through a white hole.
Black holes are places where the beaver made a mistake.
And yes, those mysterious signals that some are searching for in LIGO data and calling "echoes"? That is the beaver gnawing another hole. They just haven't yet realized who exactly they are looking for.
3.7. How we know the beaver exists and is alive.
Only through indirect effects:
· Resolution of collisions (disappearance of dark matter)
· Expansion of space at the boundary of the Universe
· Controlled acceleration of expansion
· Gnawing through (black holes as entrances, white holes as exits)
· Resonant spectra of LRDs (outputs of white holes)
· The fundamental impossibility of deriving complete equations for discrete gravity
· The random distribution of black holes
· Quantum jumps of elementary particles
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4.1. The density of unresolved collisions is maximal at the boundary of the Universe.
4.2. The beaver resolves these collisions at the boundary. Each resolution transitions an indeterminate state to a determinate one, expending energy. This energy goes into the expansion of space.
4.3. Accelerated expansion is explained by the beaver controllably accelerating.
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5.1. Observation: The rotation speed of galaxies at the periphery equals the speed at the center.
5.2. QBT Explanation: The density of unresolved collisions is distributed not locally but globally — maximal at the boundary of the Universe. The beaver, resolving these collisions, creates a gravitational potential that does not decay as 1/r but tends toward a constant. This equalizes rotation speeds at all distances from the galactic center.
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6.1. Normal resolution of collisions expands the edge. Strong resolution (the beaver miscalculated its force) creates a rupture in the discrete grid.
6.2. In our reality, the rupture is a black hole (entrance). In a parallel universe, a white hole (exit).
6.3. White hole as a resonator: λ_n = 2L/n, where n = 1, 2, 3...
6.4. Beaver burrow (Castor foramen) — a wormhole connecting universes.
6.5. Time in a discrete environment and near a black hole.
In a discrete environment, time flows uniformly across all points within a single tick. However, under the influence of hypermasses (concentrations of unresolved collisions), time can slow down, but it can never stop completely.
Time cannot be zero. t ≠ 0.
If time could be zero, we could stop it. If it could take negative values, time travel would be possible. Neither is observed. Even at the event horizon of a black hole, where time slows critically, the process does not stop. We see accretion disks, observe gravitational waves from mergers, detect radiation. Time flows — just very slowly from the perspective of an external observer.
This is a fundamental limitation of a discrete environment. Even at the deepest point of a black hole, at the very center of the rupture, time does not stop — it approaches zero but never reaches it.
Why this matters.
Imagine a scenario: humanity invents a warp drive and sends a ship to Alpha Centauri. The return path is calculated to fractions of a second — there is a narrow "window" when the Milky Way is positioned such that the ship can fly through without hitting a single speck of dust. The ship's clocks are off due to relativistic effects (no Sun, no Moon, no way to orient). How to hit the window?
You need a device that can count Planck units — the "frames" of our reality. With such a device, you can synchronize time to fractions of a second and pass through the window.
This problem shows: time cannot be zero. We can always measure it if we have a Planck tick counter. Even in a black hole, the process continues — just very slowly.
Returning to the Blender analogy.
In Blender, time flows for all objects in a scene within a single timeline. If an object enters a region with "time dilation" (e.g., a physics simulation with lower FPS), it moves slower, but it does not stop. Planck clocks (a frame counter) would show the actual speed of the process. For an observer on Earth and an observer in a black hole, time flows. It just flows slower for the second. If we could compare the readings of two Planck clocks, we would see a difference in ticks, but not a stop.
Implication for black and white holes.
Since time never stops, the process of data transfer through the rupture never ceases. Everything that falls into a black hole inevitably reaches the white hole in the parallel universe. Perhaps after a vast interval, but it reaches.
The first data obtained from a black hole (when we learn to "read" it) will show not a complete stop of time, but its critical slowdown. This will be direct confirmation of the discrete nature of time and a core prediction of QBT.
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7.1. Discovered by JWST in 2022 at z ≈ 4-8.
7.2. Anomalies: size < 100 pc, luminosity 10^10-10^11 L_⊙, red spectrum, broad lines (FWHM > 1000 km/s), no X-rays, density 20-30%.
7.3. QBT Explanation: LRDs are white holes in our reality.
7.4. Prediction: Blue and violet LRDs at z < 1.
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QBT will be considered refuted if any of the following conditions are met by 2030:
Absence of blue/violet LRDs at z < 1 at the sensitivity of Euclid and Roman Space Telescope (0 objects after 3 years).
Absence of echoes in gravitational waves after black hole mergers with masses > 30 M_⊙.
Absence of directional correlation between LRDs and supermassive black holes (p > 0.05).
Absence of the second resonant mode in LRD spectra at S/N > 100.
Absence of H(z) fluctuations at the level of 10⁻⁵.
Absence of change in the acceleration parameter q₀ over 10 years of observations (see section 12).
Detection of complete time stoppage in a black hole (t = 0) rather than critical slowdown.
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Predictions of QBT
Blue and violet LRDs at z < 1.
Correlation between directions of black holes and LRDs.
Dark matter will not be detected as a particle.
Echoes in gravitational waves from black hole mergers.
Rotation speed of galaxies at the periphery equals speed at center.
Second resonant mode in LRD spectra with I₂/I₁ ≈ 0.125.
H(z) fluctuations at the level of 10⁻⁵.
Change in the acceleration parameter q₀ over time (acceleration decreasing).
Time in a black hole critically slows down but does not stop (t ≠ 0).
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QBT does not require belief in infinite extrapolation. It says: "Here are my predictions for a finite region. Test them. If they match — use them. If not — discard them."
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For millennia, we have sought a theory of everything. Built mathematical cathedrals, multiplied entities beyond measure. Believed that laws do not depend on measurement.
Gauge invariance is based on faith, not proof.
QBT does not require faith. QBT requires testing.
Reality, like any truth, is terrifyingly simple. Or funny.
The quantum beaver.
🦫
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12.1. The beaver has reached its limit.
From the Appendix (Sections A.4–A.5), today's gnawing frequency has reached the Planck limit (2×10⁴³ s⁻¹), and its rate of growth has reached the maximum possible in a discrete environment (doubling in one Planck tick).
12.2. The beaver cannot accelerate indefinitely.
The discrete environment imposes an absolute limit on the gnawing frequency and its rate of growth. Having reached this limit, the beaver stops accelerating.
12.3. Implication for the Universe.
If the beaver has stopped accelerating, the acceleration parameter q(t) stops decreasing and begins to tend toward zero. This means:
· The accelerated expansion of the Universe is slowing down right now
· In the near future (by cosmological standards — billions of years, but the effect should be noticeable already) expansion will become uniform (q = 0)
· Then, if the beaver begins to slow down, expansion will begin to decelerate
12.4. Shocking prediction.
In the current epoch (z ≈ 0), the acceleration parameter q₀ is not constant. It is increasing (i.e., acceleration is decreasing) at the maximum possible rate dictated by the discreteness of the environment.
This means that the standard ΛCDM model, which postulates a constant dark energy (Λ = const), is incorrect. Dark energy is not constant — it reaches a limit and stops growing.
12.5. How to test this.
Compare expansion data from the last 5–10 years (DES, DESI, Euclid, JWST) with predictions:
· ΛCDM predicts: q₀ ≈ -0.55, constant over time
· QBT predicts: q₀ increases over time, approaching zero
If a change in q₀ (even 0.01–0.05) is detected over 10 years — ΛCDM takes a hit. If the change corresponds to the maximum possible rate dictated by Planck limits — QBT receives triumphant confirmation.
12.6. What if q₀ does not change?
If over 10–20 years of observations it is established that q₀ remains strictly constant to within 0.001, then:
· Either the beaver has not yet reached its limit (then our limit estimate is wrong)
· Or there is no beaver (then QBT is refuted)
But even in this case, QBT has other predictions. For complete refutation, all seven criteria from Section 8 must fail.
12.7. Unfalsifiability.
QBT becomes practically unfalsifiable because:
· If q₀ changes — QBT is confirmed
· If q₀ does not change — one can say the beaver has not yet reached its limit
· The only way to refute QBT is for all seven criteria to fail simultaneously
12.8. Final statement.
The quantum beaver has reached the limit of its capabilities. It gnaws at maximum frequency and can no longer accelerate. The Universe is ceasing to accelerate right now. Dark energy is dying. ΛCDM is wrong. Test us in 10 years.
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Appendix. Mathematical Postulates and Predictions of QBT
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A.0. Mathematical Foundation: The Riemann Hypothesis and Critique of Gauge Invariance
A.0.1. The Riemann Hypothesis as a cornerstone.
The Riemann Hypothesis (1859) states that all non-trivial zeros of the zeta function ζ(s) lie on the line s = 1/2 + it. Billions of zeros have been checked — all on the line. But this is not proof. The next one could be off the line. And so on to infinity.
A.0.2. Infinity is a process, not a number.
The Riemann Hypothesis can only be tested under potential infinity — as an infinite process. Under actual infinity, we can never say we have checked everything.
A.0.3. What this means for physics.
We postulate that the laws of nature do not depend on measurement (gauge invariance, homogeneity of the Universe). But the Riemann Hypothesis shows: there exist mathematical truths that depend on an infinite process. If such truths exist in mathematics, why can they not exist in physics?
A.0.4. Gauge invariance is not a fact, but an assumption.
QBT does not require belief in infinite extrapolation. QBT says: "Here are my predictions for a finite region. Test them. If they match — use them. As for what lies beyond the horizon — not my problem."
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A.1. Fundamental Equation of Gnawing Rate
The relationship between the expansion rate H(t) and the gnawing frequency ν_gnaw(t):
H(t) = (ν_gnaw(t) · δR) / R(t)
The gnawing frequency expressed in terms of the observable quantity H(t):
ν_gnaw(t) = (H(t) · R(t)) / δR
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A.2. Today's Gnawing Frequency (Verified Calculations)
Input data:
· H₀ = 73 km/s/Mpc = 73 × 1000 / (3.086 × 10²²) ≈ 2.36 × 10⁻¹⁸ s⁻¹ (taken as 2.4 × 10⁻¹⁸ s⁻¹)
· R₀ = 14.4 billion light-years = 14.4 × 9.461 × 10¹⁵ ≈ 1.36 × 10²⁶ m
· l_p = 1.6 × 10⁻³⁵ m
Calculation:
H₀ × R₀ = (2.4 × 10⁻¹⁸) × (1.36 × 10²⁶) = 3.264 × 10⁸
Division by l_p: (3.264 × 10⁸) / (1.6 × 10⁻³⁵) = 2.04 × 10⁴³ s⁻¹
Rounded: 2 × 10⁴³ s⁻¹
Conclusion: ν_gnaw,0 = 2 × 10⁴³ s⁻¹
This coincides with the Planck frequency (1 / t_p ≈ 1.85 × 10⁴³ Hz). The discrepancy is within the margin of error of the input data. The beaver has reached its limit.
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A.3. Today's Gnawing Acceleration
q₀ ≈ -0.55
ν_gnaw,0 = 2 × 10⁴³ s⁻¹
N_total = 10²⁶
Formula: ν̇/ν = -q₀ · ν_gnaw / N_total
Calculation: -(-0.55) × (2 × 10⁴³) / 10²⁶ = 0.55 × 2 × 10¹⁷ = 1.1 × 10¹⁷ s⁻¹
Conclusion: ν̇_gnaw / ν_gnaw = 1.1 × 10¹⁷ s⁻¹
Doubling time: τ_double = ln(2) / (1.1 × 10¹⁷) ≈ 0.693 / 1.1 × 10⁻¹⁷ ≈ 6.3 × 10⁻¹⁸ s
t_p = 5.4 × 10⁻⁴⁴ s
6.3 × 10⁻¹⁸ s > 5.4 × 10⁻⁴⁴ s (difference of 10²⁶ — due to rounding and scales). Theoretically, doubling occurs in t_p. Our numerical discrepancy comes from the fact that in the formula ν̇/ν = -q₀ · ν_gnaw / N_total, the denominator N_total ≈ 10²⁶. With exact values, τ_double = t_p. We take: τ_double ≈ t_p.
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A.4. Resonant Modes of a White Hole
Resonance condition: λ_n = 2L / n, n = 1, 2, 3...
Mode amplitude ratio: I_n / I₁ = (1/n²) · (Q₁ / Q_n), where Q_n = Q₁ / n
For n = 2: I₂ / I₁ = (1/4) · (1/2) = 1/8 = 0.125
Conclusion: I₂ / I₁ = 0.125 (exact)
Quality factor of the LRD resonator: Q ≈ 100 (from line widths FWHM > 1000 km/s).
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A.5. Fundamental Limitation of Time
In a discrete environment, time cannot be zero: t ≠ 0.
Even at the center of a black hole, time critically slows down but does not stop. The process of data transfer through the rupture never ceases.
The first measurements of time near an event horizon will show a slowdown approaching zero, but never reaching zero. This is a direct prediction of QBT.
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A.6. Final Formulas of QBT
Formula 1: ν_gnaw = (H · R) / l_p = 2 × 10⁴³ s⁻¹
Formula 2: I₂ / I₁ = 0.125
Formula 3: τ_double = t_p (doubling of gnawing frequency in Planck time)
Formula 4: q₀ changes over time, tending toward zero
Formula 5: t ≠ 0 (time does not stop)
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🦫
I'm casually interested in Astrophysics but I am wondering if it is a field worth going into or putting a lot of thought towards. Has thought reached a roadblock where tech needs to develop further before more theories can become facts or are things accelerating?
I am worried that we may have reached / be reaching the limit of what is testable / provable with human technology and astrophysics will just become a more subjective field akin to philosophy where there are many good ideas but none that will ever be perfect or fully confirmed
If not, what are some exciting upcoming experiments / new tech being developed to advance the field? I am aware of Cern's goal to create dark matter