The Astronomy Thread

Furry

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This statement is nonsense. The universe is nothing but change. Gravity is constantly changing as everything changes mass/energy and moves relative to each other.



No, you. You're the one with the crazy talk. Show us the supposed requirement that gravity propagates instantly, against what everyone since Einstein has claimed.
Cool you understand the philosophical reasoning behind why the theory is retarded. It assumes objects are cohesive entities, which is clearly not true.

As for orbits I dunno I guess I can just use NASA’s formula.

r = a(1 – e2)/(1 + e cos φ)

As you can clearly see the speed of gravity is assumed to be infinite in this formula. To understand further how the magic space memory that knows where gravity will be in the future works in the theory you support, read up on gravitoelectromagnetism and come back more prepared to fight.
 
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Tuco

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Cool you understand the philosophical reasoning behind why the theory is retarded. It assumes objects are cohesive entities, which is clearly not true.

As for orbits I dunno I guess I can just use NASA’s formula.

r = a(1 – e2)/(1 + e cos φ)

As you can clearly see the speed of gravity is assumed to be infinite in this formula. To understand further how the magic space memory that knows where gravity will be in the future works in the theory you support, read up on gravitoelectromagnetism and come back more prepared to fight.
All your questions have answers in https://arxiv.org/pdf/gr-qc/9909087

Aberration and the Speed of Gravity

Abstract The observed absence of gravitational aberration requires that “Newtonian” gravity propagate at a speed c g > 2 × 1010 c. By evaluating the gravitational effect of an accelerating mass, I show that aberration in general relativity is almost exactly canceled by velocity-dependent interactions, permitting c g = c. This cancellation is dictated by conservation laws and the quadrupole nature of gravitational radiation.





The equation you're looking for is

1748226910398.png


Note that the only word I understood in that paper is the word "retarded".
 
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Furry

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All your questions have answers in https://arxiv.org/pdf/gr-qc/9909087

Aberration and the Speed of Gravity

Abstract The observed absence of gravitational aberration requires that “Newtonian” gravity propagate at a speed c g > 2 × 1010 c. By evaluating the gravitational effect of an accelerating mass, I show that aberration in general relativity is almost exactly canceled by velocity-dependent interactions, permitting c g = c. This cancellation is dictated by conservation laws and the quadrupole nature of gravitational radiation.





The equation you're looking for is

View attachment 587690

Note that the only word I understood in that paper is the word "retarded".
Good paper, they fully realize that they are arguing for a system where empty space is the force that magically guides planets and stars along, rather than the bodies themselves. They say it themselves in the beginning:

1748227496759.png


I don’t care if people support or don’t support this theory, but I won’t let people protend the theory is something other than it is.

I don’t have time to go deep into this paper until Tuesday.
 
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Edaw

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Okay, let’s explain this in a super simple way, like talking to a 5-year-old, to help our friend understand why their idea about gravity moving super fast (faster than light) is not right.



Hey there! Let’s talk about gravity!

Imagine you have a toy car, and you push it across the floor. When you push it, it moves right away, right? A long time ago, people thought gravity worked like that too—like if the Sun disappeared, Earth would stop circling it right away. They used a formula (like the one you showed, r = \frac{a(1 - e^2)}{1 + e \cos \phi}) to figure out how planets move in orbits. That formula doesn’t talk about how fast gravity moves, so people assumed it was instant, like magic.

But then a super smart person named Einstein came along with a better idea called general relativity. He said gravity isn’t like an instant push. Instead, it’s like ripples in a pond when you drop a pebble. Those ripples travel at a certain speed, and for gravity, that speed is the same as light—super fast, but not infinite!

Here’s why the old idea is wrong:
  1. Gravity isn’t magic. The formula you mentioned is from a guy named Newton, who lived a long time ago. It’s great for figuring out orbits, but it doesn’t tell us how fast gravity travels. It just assumes gravity is always there instantly, like a magic string pulling planets. Einstein showed that’s not true—gravity moves at the speed of light, like a message sent really fast but not instantly.
  2. No “space memory” needed. You said something about gravity knowing where things will be in the future, like planets having a magic memory. That’s not how it works! Planets move smoothly because space is curved around the Sun, like a bowl that keeps a marble rolling in a circle. If the Sun disappeared, it would take about 8 minutes for Earth to notice because the gravity ripple travels at light speed, not instantly. Scientists proved this with something called gravitational waves—they measured them and saw they move at light speed, not faster.
  3. Gravitoelectromagnetism isn’t magic either. That big word you mentioned is just a way to describe gravity in a way that’s similar to how electricity works. It’s part of Einstein’s ideas, and it still says gravity moves at light speed, not infinite speed. No magic memory is needed—just math that matches what we see in space.
  4. Why the old formula seems confusing. The formula you shared (r = \frac{a(1 - e^2)}{1 + e \cos \phi}) is awesome for drawing the shape of orbits (like circles or ovals), but it doesn’t tell us anything about how fast gravity moves. It’s like a map that shows where a road goes but doesn’t say how fast you drive on it. Newton didn’t know about light speed, so his formula doesn’t include that part. Einstein added that piece to the puzzle.

So, why are you wrong? You thought gravity moves infinitely fast because an old formula didn’t mention speed, and you heard about a “space memory” idea. But that’s based on old thinking before we knew better. Scientists like Einstein and experiments with gravitational waves (like when two black holes smashed together) show gravity moves at the speed of light. It’s not instant, and there’s no magic memory—just space acting like a big, curvy playground that follows rules we can measure.

If you want to learn more, look up “gravitational waves” or ask about how Einstein’s ideas work. You’re super curious, and that’s awesome! Keep asking questions, and we’ll figure it out together!

1715631011139.png
 
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Furry

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LIGO and VIRGO have detected numerous gravitational waves adding more evidence in favor of Einstein's theory?
Ligo and Virgo are incapable of distinguishing between magnetic and gravitational waves.
 
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Burns

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Ligo and Virgo are incapable of distinguishing between magnetic and gravitational waves.
According to this explanation they can (from when the LIGO was about to be turned back on after upgrade, 9 years ago)[timestamped to relevant part]:


From the first 2 detections 8 years ago (timestamped to relevant part):


Edit: meant to link first video instead of second (thought the second had the explanation linked in the first), but second showed the first two detection wave patterns, so left it.
 
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Captain Suave

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Cool you understand the philosophical reasoning behind why the theory is retarded. It assumes objects are cohesive entities, which is clearly not true.

As for orbits I dunno I guess I can just use NASA’s formula.

r = a(1 – e2)/(1 + e cos φ)

As you can clearly see the speed of gravity is assumed to be infinite in this formula. To understand further how the magic space memory that knows where gravity will be in the future works in the theory you support, read up on gravitoelectromagnetism and come back more prepared to fight.

Newtonian equations are good enough for a lot of work. That equation is useful and convenient, but does not describe our most accurate understanding of physics.

Ligo and Virgo are incapable of distinguishing between magnetic and gravitational waves.

LIGO and VIRGO are laser interferometers can don't detect magnetic waves at all. They're just really, really, really, REALLY sensitive rulers.
 
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Captain Suave

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Verifiably false again.

Heres LIGO’s own published paper on the subject, though they prefer the term “magnetic noise” for obvious reasons.


Meh. Earth's magnetic field inducing very low-frequency current resonances through the entire facility and its equipment (paper even mentions metal buildings) is not the same thing as the primary detection mechanism (laser distance measurement) intentionally picking up general EM waves. They're effectively measuring the distance between Earth and Saturn to the precision of the width of a human hair, so yeah, if anything predictably vibrates at any level for any reason they'll want to filter that out. They couldn't detect any kind of non-resonant signal that wasn't manifesting as physical vibration.
 
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Cybsled

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The answer never becomes 3 just because we really want it to. FTL is still impossible, and anything that even could (theoretically) travel FTL would still go through time backwards.

Just to clarify, when I say FTL, I don't mean actually traveling faster than light in terms of linear speed. Mathematically it has been shown that it could be possible to warp space in a localized region and so long as you could produce propulsion, you could effectively "ride the distortion" and achieve the ability to travel distances in space faster than light could normally without actually going faster than light in the linear travel sense. If I recall, the original equation would have required all the energy in the universe (practically impossible), but later it was refined to effectively require the energy in a star. Maybe not impossible if we reached kardashev scale 3 civilization, but it is still no where near the realm of possibility based on our current technology or understanding and resources.

I think it is bold to state it will never be possible because that presumes we know all there is to know. Not a guarantee we ever will find a way, but one should concede that there remains the possibility that there could be.
 

Furry

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Meh. Earth's magnetic field inducing very low-frequency current resonances through the entire facility and its equipment (paper even mentions metal buildings) is not the same thing as the primary detection mechanism (laser distance measurement) intentionally measuring general EM waves. They're effectively measuring the distance between Earth and Saturn to the precision of the width of a human hair, so yeah, if anything predictably vibrates at any level for any reason they'll want to filter that out.
If it’s detected by the detector, how is it not interfering with detection? Why do you start talking about subjects you’ve never bothered to research? If you have followed this thread since the mid 2000s you’d know I actively follow the research and read many scientific papers.

It detects magnetic waves. A magnetic source for so called gravitational waves cannot be ruled out.
 

Big Phoenix

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Missing a few zeroes there. Average distance between stars is 4LY in a close cluster. Average number of stars with a habitable earth like planet is 1 per 1-10k stars, (7% of stars are sun like, and up to 10-20% of those have earth like planets, based on current optimistic estimates. But "earth like" just means rocky/iron core/magnetic field and includes massive planets 3-10x the mass of earth which is bullshit.) Earth is the absolute limit of chemical energy's ability to reach escape velocity. meaning if Earth were even 10% more massive than it is, we could never escape orbit. Actual number of planets you could potentially colonize and then eventually leave again with a new generational ship to continue spreading is off by an order of magnitude.
Fusion power would allow you to travel to nearby star systems within a few dozen years with starships larger than the biggest shipping containers we build today. Seeing as how Voyagers which are 1970s tech, no reason to think advanced societies couldnt build colony ships that can sustain themselves for 20-30 years.

And you dont need to find Earth like worlds to sustain civilization spreading out. As long as the system has anything like Mars, Titan, Pluto or even a Kuiper Belt you will be able to easily sustain and expand your civilization if you can harness fusion power.
 
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Kajiimagi

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I tried reading all this nerd garbage and now I'm sure I have so much nerd on me I'll never get laid for the rest of my life.....and I'm married.


I'll give you this though, you are nerding off in the correct thread. Hmm paging Dr.Retarded Dr.Retarded , this would be a good place for a food derail. I had Chinese take out tonight - GO.
 
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Kharzette

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The math for interstellar travel is tricky, but very doable. You need electricity based propellent free propulsion. There are alot of these sorts of drives being dreamed up and tested and so far none of them work, but we'll get there eventually.

Another is a 20ish year electricity generating power source. Fission is fine.

The third is a big fat stack of ice on the front of the ship. Probably a mile or two thick. Make a long skinny craft with ice at the front.

If you have the juice and the engines to accelerate at 1g, you can get just about anywhere in the known universe in 20 years ship time. Unfortunately closer stars are not that much quicker the way relativity works.

There is no speed limit. There is no magic billion joules to reach it. You just accelerate and keep going. Power requirements are in the ship's frame of reference.

There might be an eventual diminishing return on tonnage of ice vs power needed vs engine mass. Hitting dust will ablate away alot of ice, and even in the voids there's a hydrogen atom every few meters cubed you'll run into. Needless to say if you hit anything bigger than a pebble you'll likely outshine a galaxy with the resulting explosion.

Also the normal light of stars around you all moves to a focused point of ultra hard gamma rays that will ablate quite a bit of ice. (wierdly it moves to the back of the ship, but hits the front)
 
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Sylas

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Holy hell is this thread turbofucked. Sylas arguing that the most popular answer to the Fermi Paradox is the only possible answer and then dying on that hill makes for some bad reading.


My favorite answer: The Prime Mover switched the "Enable Life" bit some 4ish billion years ago and said, "Let the games begin."
Excuse me, i'd hardly call it the most popular answer? I asked AI to list the most popular answers to the fermi paradox and not one of them was "The fermi paradox is retarded and is based on a really stupid assumption". no, I only get the following:

The Rare Earth Hypothesis: The conditions for life to arise and evolve to intelligent levels are exceptionally rare, making it unlikely for life to exist elsewhere.
The Great Filter: There may be a "filter" that prevents life from reaching advanced stages, such as a barrier in the early stages of life or a catastrophic event that wipes out civilizations.
The "Dark Forest" Hypothesis: Advanced civilizations might be intentionally hiding, perhaps due to a fear of other powerful civilizations.
The "Big Silence": We may be the only intelligent species in the universe, and other civilizations may not have developed the ability to communicate with us.

From the wiki here is the chain of assumptions:

There are billions of stars in the Milky Way similar to the Sun. <-- Ok
With high probability, some of these stars have Earth-like planets in a circumstellar habitable zone. <-- Yep
Many of these stars, and hence their planets, are much older than the Sun. If Earth-like planets are typical, some may have developed intelligent life long ago. <-- still good
Some of these civilizations may have developed interstellar travel, a step that humans are investigating. <--Here it is! this assumption is retarded.

The rest of the logic is based on this false premise and is therefore meaningless.

Just to clarify, when I say FTL, I don't mean actually traveling faster than light in terms of linear speed. Mathematically it has been shown that it could be possible to warp space in a localized region and so long as you could produce propulsion, you could effectively "ride the distortion" and achieve the ability to travel distances in space faster than light could normally without actually going faster than light in the linear travel sense. If I recall, the original equation would have required all the energy in the universe (practically impossible), but later it was refined to effectively require the energy in a star. Maybe not impossible if we reached kardashev scale 3 civilization, but it is still no where near the realm of possibility based on our current technology or understanding and resources.

I think it is bold to state it will never be possible because that presumes we know all there is to know. Not a guarantee we ever will find a way, but one should concede that there remains the possibility that there could be.
Yes I know you don't mean accelerating to FTL, unlike furry you seem to have an understanding of math.

The energy to fold spacetime is somewhat known theoretically, it's a black hole. just hop in and hope you pop out from a white hole somewhere else in the universe. it's always going to be a one way trip with no way to communicate back the results so it's use for colonizing galaxies is meaningless and unknowable. Same is true for all such theoretical "natural" methods of FTL travel, finding wormholes and traveling through them before they collapse, etc.

Building a device to harness the energy required to create manmade blackholes or wormholes or whatever, assuming its even possible to make these things much less stabilize them or miniaturize them enough to slap them on a spaceship? Then you end up back in fantasy realm, type 1-3 "civilizations", Dyson spheres and shit. How much matter does it take to build a Dyson sphere? Oh twice as much matter that exists in the solar system including the entire Oort cloud? Ahh cool story bro. So we spend a few hundred thousand years sublighting back and forth to the next 3-4 available stars lassoing up and gathering up all the matter and bringing it back to build a device to harness all the Sun's power. Then somehow we transfer that power to a space ship, with hopes and wishes and fairy dust I guess.

It doesn't work. You want to know how I know it doesn't, cus someone would have already did it.

It's just hogwarts in space.
Fusion power would allow you to travel to nearby star systems within a few dozen years with starships larger than the biggest shipping containers we build today. Seeing as how Voyagers which are 1970s tech, no reason to think advanced societies couldnt build colony ships that can sustain themselves for 20-30 years.

And you dont need to find Earth like worlds to sustain civilization spreading out. As long as the system has anything like Mars, Titan, Pluto or even a Kuiper Belt you will be able to easily sustain and expand your civilization if you can harness fusion power.
uh what?

Fusion is just a more energy efficient style of nuclear power to fission. Making bigger atoms from little atoms rather than what we currently do, which is make little atoms out of bigger atoms. All it does is create heat.

All we use any of it is to heat fucking water to make steam. we use that steam to spin turbines which spin magnets that make electricity. We'd use that electricity for some sort of X-Ray ionic propulsion like the Xenon thruster or whatever else kind of engine we come up with that works solely off of electricity.

Fusion doesn't change that, it just changes what we can use for fuel (hydrogen, super abundant element) to heat water, rather than super heavy rare minerals like uranium or plutonium.

Fusion is nice and most likely necessary so that we can stop at asteroid belts and mine ice, which gives us hydrogen and oxygen, both things we'll need. There aren't any gas stations in the universe that sell uranium. But fusion doesn't make our car faster, that's ridiculous.

All of human invention is just building better mouse traps, figuring out more efficient ways to exploit physics to get work done. In all of our efforts we've found nothing more efficient than the fact that water+ heat creates steam, which rises, and as it rises it cools, becomes liquid again, which is heavier than air so it falls back down, allowing us to create an endless steam cycle loop with very few moving parts outside the turbine, and all it requires is heat. We've just upgraded from trees to coal to oil/gas to nuclear for the source of the heat, but the underlying physical properties we're exploiting have not changed.

this post is getting too long i'm not going to quote kharzette's weird icicle ship post, but will say the energy required to increase velocity does in fact, follow the laws of physics and will increase exponentially as you approach c, so no putting a giant icicle on the front of your space ship doesn't let you zoom around at speeds many times the speed of light.
 
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Cybsled

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And you dont need to find Earth like worlds to sustain civilization spreading out. As long as the system has anything like Mars, Titan, Pluto or even a Kuiper Belt you will be able to easily sustain and expand your civilization if you can harness fusion power.
The issue would be pressures to expand on a long journey like that - your own solar system could sustain you in that case. The only strong reason to venture elsewhere is because you have gotten to the point where you are close to exhausting the resources of your solar system. Economically it wouldn't make sense because any round trips would be measured in decades or centuries unless you literally found unobtanium from Avatar or whatever.
 

Tuco

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It's just hogwarts in space.
For an ape in a species that's been using nuclear reactions for less than 100 years, you seem *really* confident about the limitations of physics. I hope for your own sake you don't approach every situation in life with the assumption, "I know everything" like you're doing here.
 
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Furry

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For an ape in a species that's been using nuclear reactions for less than 100 years, you seem *really* confident about the limitations of physics. I hope for your own sake you don't approach every situation in life with the assumption, "I know everything" like you're doing here.
Yea, it's really bizarre to me. I'm super, incredibly critical of some fields of science and always have been. Quantum computing is a scam, QE a scam, Global warming a scam, magnetically sensitive interferometers for measuring gravity waves a scam, ect. Even so, I've whole heartily supported people researching into these subjects without government backing. In the case of Quantum computing, I think very real advances have been made in field of spin stabilization and measuring of atoms in this subject.

For interferometers, great advances have been made in stabilization and muting of interference which I think have merit. Just because a base science seems pointless to me, doesn't mean I'm not open to the idea that I'm either categorically wrong, or that adjacent discovers of use can be made.

In science, unexpected discoveries have often led to great things. So I'm all for pushing any boundry in what we can do and seeing where it goes. Anyone who thinks they know where the answers are is stupid.

I think time travel is a completely retarded concept, but if someone wants to investigate it seriously, have at it.
 
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Sylas

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For an ape in a species that's been using nuclear reactions for less than 100 years, you seem *really* confident about the limitations of physics. I hope for your own sake you don't approach every situation in life with the assumption, "I know everything" like you're doing here.
The physical universe does not change just because our ability to more accurately describe and measure it improve. Gravity existed before newton, black holes existed before einstein, etc.

Can human beings live on the surface of the sun, biologically? No special materials or suits or anything, just you in cargo shorts and a wife beater, will you survive? The physics says no, not ever. No increase in our ability to measure quarks or accurately predict the movement of celestial bodies or interactions of sub-atomic particles will change that answer, it will always be no.

I don't think it's a question deserving of much discourse or serious debate. if you want to try it, feel free. I don't think any "thought experiment" should exist trying to explain why we don't have rental and vacation properties on the surface on the sun? I don't think there's any merit to this line of thought. It's fine for a facebook quiz, about as apt as which kind of potato are you? but it's not science.

I think Time travel is absurd on it's face. I also recognize that mathematically, you would have to solve time travel (tachyons exist which travel FTL and thus travel backwards through time) on the road to solving FTL (tachyons require the same infinite energy to decelerate down to the speed of light just as normal matter would require infinite energy to accelerate to the speed of light).

ie you would have to harness tachyon's somehow thus master time travel in order to gather the energy necessary to solve FTL. Thus if you believe time travel to be absurd then you must recognize that FTL is doubly absurd. In a game of Civ time travel unlocks before FTL.