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I liked the old YouTube, pre google, better.
The Physics That Makes Interstellar Travel IMPOSSIBLE ...
- Thread starter BusyLittleShop
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Our lives are short compared to the bigger picture. Everything seems new to me. I just hope I don't fall off when the planet flips, just joking of course.
We = humans and those humans who have taken an interest in learning what we know.
I do know quite a bit...
"The Hab Conspiracy" was a novel, I think from the early '80s, with the premise that ice builds up on the Earth's poles, creating instability.
Every few million years, the heavy poles are swung to the outside, flipping the Earth 90°. The new poles, previously at the equator, begin to accumulate I've, and the cycle begins anew.
Interesting concept.
And how to visualize many billion times the speed of light? With a simple example. 
Forget interstellar space travel. We can't get back from Mars, assuming we ever got there successfully.
Person A: "What do you think about Shakespeare?"
Person B: "I don't think Shakespeare's stories are any good"
Person A: "Have you ever read Shakespeare?"
Person B: "No."
Humans are funny animals who not only love to opine about topics they have little to no knowledge about, they love to vehemently opine about these topics. It's hard to say what we do or don't know about the universe when you yourself don't know what we do or don't know about the universe.
Person B: "I don't think Shakespeare's stories are any good"
Person A: "Have you ever read Shakespeare?"
Person B: "No."
Humans are funny animals who not only love to opine about topics they have little to no knowledge about, they love to vehemently opine about these topics. It's hard to say what we do or don't know about the universe when you yourself don't know what we do or don't know about the universe.
https://www.livescience.com/space/c...-wrong-with-our-understanding-of-the-universe
I think we are just learning how the universe works. Discoveries of the James Webb satellite are rewriting what should be considered possible in the universe and ripped up many of the "accepted" models.
We have such limited data collecting ability in our infinitesimal corner of the universe that exclusion bias is assured.
Very small changes in something like the cosmological constant can have profound effects on the large scale structure of the universe but it is itself a small part of what we know and have measured.
Experimentally, quantum chromodynamics (quarks) is correct. Quantum mechanics (how small things behave) is correct. Quantum electrodynamics (how electromagnetisms works at small scales) is correct. These three things accurately explain most phenomena in the universe minus a quantum description of gravity (we have a very good Newtonian macro-scale description) that is only relevant in extremes like blackholes and in quantum events. An understanding of dark matter/energy is also missing.
We know a whole lot and can explain a whole lot with precise experimental accuracy and the fact that we can't explain everything perfectly doesn't mean we don't know anything. There are some great books written for lay people on all aspects of physics - some of my favorites or Brian Green, Larry Krauss, and Sean Carroll. These even come in audio books. If you're interested, give them a read or listen and if at the end of a book on Newtonian physics, quantum chromodynamics, quantum electrodynamics, quantum mechanics, blackholes and general cosmology you still think we don't know anything, I'll seriously listen to why you think that is true. They are all actually easy reads and listens.
There is no normal but as we see it being a human being we think there is a normal . I can’t see how anyone would believe there is a physical limitation to speed of travel.
We know nothing. It wasn’t too long ago that we thought the Earth was square.
We are a primitive species as much as we don’t want to admit it.
Anyway, as far as regarding the poles they always move and they reverse and they go forward and they also switch. The poles actually switch from North Pole to South Pole, South Pole to North pole.
It takes a very long time. The last one was 780,000 years ago. Our so-called advanced society has only been around for about 200 years, we are nowhere advanced.
The link below has unlimited links to links of links of NASA data, including magnetic headings. I didn’t care to go too much into it.
https://www.ncei.noaa.gov/news/tracking-changes-earth-magnetic-poles
If you are very, very patient and have a capable device, this link goes to a NASA animation of just the last four or 500 years or so
It probably takes about four or five minutes to load
https://www.ncei.noaa.gov/maps/historical-declination/
We know nothing. It wasn’t too long ago that we thought the Earth was square.
We are a primitive species as much as we don’t want to admit it.
Anyway, as far as regarding the poles they always move and they reverse and they go forward and they also switch. The poles actually switch from North Pole to South Pole, South Pole to North pole.
It takes a very long time. The last one was 780,000 years ago. Our so-called advanced society has only been around for about 200 years, we are nowhere advanced.
The link below has unlimited links to links of links of NASA data, including magnetic headings. I didn’t care to go too much into it.
https://www.ncei.noaa.gov/news/tracking-changes-earth-magnetic-poles
If you are very, very patient and have a capable device, this link goes to a NASA animation of just the last four or 500 years or so
It probably takes about four or five minutes to load
https://www.ncei.noaa.gov/maps/historical-declination/
"Everything we know" is where your argument falls apart. We don't know what we don't know
Wow the magnetic lines have moved a lot in my lifetime. Looks like Santa at the north pole has had to move a lot over the decades. Because of the North Pole movement
It doesn't fall apart at all and the counter to your argument is of course unknown unknowns exist but that is a tautological argument and it doesn't address what we are talking about here. The existence of unknown unknowns does not invalidate known knowns. If hidden variables existed in Newton’s time, that did not make Newtonian mechanics false. It made it incomplete. And incompleteness is not ignorance.
Your position confuses incompleteness with ignorance. Scientific knowledge does not require omniscience. It requires: 1. Predictive accuracy, 2. Internal consistency, 3. Reproducibility, and 4. Falsifiability. By those standards, we know an extraordinary amount.
Modern physics allows us to: 1. Predict planetary motion centuries in advance using General Relativity; 2. Design GPS systems that require relativistic corrections to function; 3. Build semiconductors using quantum mechanics; 4. Detect gravitational waves exactly as predicted by Einstein; 5. Model stellar evolution and nucleosynthesis with high precision. If we “knew nothing,” these systems would not work.
The real power of what we know is that multiple independent frameworks converge on the same empirical truths: 1. Quantum Mechanics accurately describes subatomic phenomena; 2. General Relativity describes gravity at cosmic scales; 3. The Standard Model predicts particle interactions with extreme precision; 4. Cosmology predicts the Cosmic Microwave Background spectrum before it was measured. When independent models align with experimental data across scales, that is strong evidence of real knowledge. There are known open problems: 1. Quantum gravity; 2. Dark matter; 3. Dark energy; 4. Unification and surely there are unknown open questions too. But having unanswered questions does not erase experimentally validated knowledge. Medicine does not become useless because it cannot cure every disease. Physics does not become ignorance because it lacks a Theory of Everything.
Scientific knowledge is provisional, but that does not make it arbitrary. We do not need to know “everything” to know “a great deal.” Physics has produced a coherent, predictive, experimentally validated model of reality spanning 15 orders of magnitude in scale. That is not ignorance. That is extraordinary knowledge, even if incomplete.
However, if YOU don't have a general grasp on that knowledge then sure, I can see why you hold the position you do but that's your issue, not an issue with what humans know.
We know, and have timed the speed of light. Apollo 11 left a mirror that we've fired a laser at, and timed it's journey there and back. (Around 3 seconds round trip). Same as a radio wave. (Also void of matter).
Here at Fermilab, along with our largest particle accelerator (CERN), we can get close to light speed. (99.9999%), but have never exceeded it. We have also proved that time slows with an increase of speed. (The clocks in orbit on the GPS satellites run slower than the ground based clocks).
So a lot of Einstein's theories have been proven out over the years as technology increases. Is there a possibility we could get something to go faster? Perhaps. But so far everything points to light as the universes speed limit.
This conflates an engineering limitations (can we build something that exceeds the sound barrier) with physical limitations predicted by physics and experimental measured and validated. Breaking the sound barrier didn’t show physics was wrong. It showed engineering had to catch up to physics. Today we predict subatomic particle behavior to 10 decimal places, correct GPS clocks using relativity, and model the early universe from measurable background radiation. That’s not ‘knowing squat.’ It’s a deeply experimentally validated framework that works across scales. We don’t know everything, but the unknown sits on top of an enormous foundation of what we demonstrably do know.
A massive object cannot reach the speed of light because the Lorentz factor becomes infinite as velocity approaches the speed of light. That drives total energy and momentum to infinity. In spacetime terms, massive objects follow timelike trajectories and cannot transition to lightlike trajectories. The barrier is mathematical and geometric, not technological.
For faster than light travel to be possible, something fundamental in relativity would have to be wrong. Special Relativity shows that as an object with mass moves closer to the speed of light, the energy required to keep accelerating it increases without bounds. At exactly the speed of light, the required energy becomes infinite. Since infinite energy is physically impossible, objects with mass cannot reach that speed.
This is not just an energy problem, it is built into the structure of spacetime. Massive objects move along what are called timelike paths, while light moves along lightlike paths. To exceed the speed of light, an object would have to shift into a completely different category of motion, which relativity does not allow. Doing so would also create causality problems, where events could appear to happen before their causes in some reference frames.
So for faster than light travel to work, we would have to overturn Lorentz invariance, the relativistic energy equation, or the basic geometry of spacetime itself. All of those have been confirmed experimentally to extremely high precision. That is why the speed of light is understood as a structural limit of reality, not a technological barrier. What would it mean for the Lorentz factor to be wrong? It would mean the 38ms time difference between GPS satellite time and earth surface time would be wrong and your GPS wouldn't be accurate and it would drift 10km per day. The Lorentz factor can't simultaneously predict this time difference but also be wrong about the infinite energy required for massive objects to reach the speed of light - for one to be true, the other must be true. Experimentally, the increases measured in energy/momentum are unbelievably accurately predicted by the Lorentz.
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There is no point trying to explain to folks things that are scientific facts, when they’re just going to run their imaginations. Many people tried before you @PWMDMD and were met with “just imagine” type of argumentation. Their basis is science-fiction, with the emphasis on fiction. And if you try bringing in science, they’ll just bring more fictional examples.
They haven’t called you close minded yet, but just wait…
They haven’t called you close minded yet, but just wait…
His arguments are quite sound actually, because the stuff we do know is 100% replicable and measurable with a very high degree of accuracy.
The fallacy of your argumentation is that, in your view the things we don’t know will somehow invalidate the things we do know, once we discover them.
Oh trust me, this is not the only topic or place on the internet where I occasionally choose to beat my head against a brick wall....I've said it out loud, what people choose to do or not do with it is their choice, but they can't honestly say no one ever made these arguments to them.
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