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I had a debate with my brother about this when I was young. It's a wonderful debate. I remember a point that if the Enterprise transporters managed to copy the entire of my brain, including all the memories, then from the point of view of the materialised 'new me' my historical memory would tell me I'm the same person.

I would remember walking up to the transporter pad, saying 'energise', and materialising at the destination. My memory is clear, and I am utterly convinced that that person before was the same me.

Then again, I look back now at some of my dim early memories, and realise how fallible memories are. I remember distinctly everyone saying 'Kindergarden' and read it as such, and only recently did I discover it was in fact 'Kindergarten'. How could I get it wrong, in particular a word so frequently used? I struggle to remember memories in early childhood - my grandmothers house, dim cloudy days and mist, a tornado? (I don't think it was, but at the time I thought I saw one). I know it is logical to think that my body was there experiencing things, but to be honest, 'I' wasn't there - I simply can't be where I can't remember being.

Add to this that if I took a prescription drug that alters the way I think, could you say that that was me? I suppose my conclusion is our experience is subjective, and paradoxically also not all of who we are. Evidence tells me that I'm more than my memories, and thus I agree with you @gwolffe356 - I wouldn't step on that transporter pad either.

About life extension though - that is also a scary thought. Imagine all the grumpy old men we know, and imagine them living for another 10,000 years. They would be very, very, very grumpy by then.

@MultiTool - that's fantastic - yes this is what I was thinking definitely the first step. Getting a 'basic' material like lunar regolith, and being able to configure it using simple processes to form new tools, and thus also print new functions into larger and larger structures.

The other component that we need to work on is 'intelligence'. Ie. do we 'print' electronics? I suppose as in your link / paper we could extend it to receive radio signals, and via simple/primitive logic we can control the robot. I think replicating in-built computers is one hurdle too far for our current ability due to difficulty trying to use these to create transistors, circuits and memory chips, and we may need to still rely on industry sourced electronics to control actuators to coordinate the machines.

That way, then all we need is primitive communication with each machine. Perhaps a simple antennae feeding each actuator, and 'simple' old-school circuits.

Keep in mind I think this technology would be best if we have an exponential growth of them to leverage from simple to complex, and scale up - so the power of them is not in their individual intelligence, but in their collective coordination. So:
1. 10 machines that can make another 10
2. 100 machines that can make another 10 each
3. 1000 machines in 3 generations only, which could then start to specialise
4. in 4 generations we could have 10,000 machines that are now specialised to create a large-scale structure (for instance a space-scraper, O'Neill Cylinder, or simply another larger factory) but they all need to be coordinated and controlled to act with a singular purpose.

So - I suppose we are looking at something similar to droneshowsoftware.com to control them - but far more advanced.

Again imagine the ring is not a ring, but a whole series of ISS space stations. There is no gravity in the ISS, because your 'motion' as a person is the same as the ISS.

My answer was saying the ring should be in orbit, as in moving around the Earth, as there is no physical material that could withstand the enormous forces required if it was stationary. However, if you want gravity to be experienced on the ring, then the ring as you say should be stationary (or close to). Then all parts of the ring would be falling towards the Earth as well. If you can create an imaginary material that retains its shape then I suppose it is possible for the ring to be stationary.

Well, if the ring is orbiting it depends on its altitude. Satellites that are closer to Earth must orbit faster than those further away.

Sure - you can build a 'ring' around any planet! A glass dome around a planet wouldn't do much in my opinion, because it would just be the same as it is now. To fill it with atmosphere, perhaps dome around the canyons first?

A1) 20
B1) 20
C1) 1

A2) 20
B2) 20
C2) 0

A3) 20
B3) 20
C3) 20

A4) 20
B4) 0

A5) 20
B5) 0
C5) 0

In summary: I believe the scale of the universe is such that it is simply impossible to fathom life, intelligent or otherwise, does not exist elsewhere. However, we see absolutely no evidence of that on Earth, nor in our solar system (except a tantalising glint of a possibility in Venus, hence the 1).

It's the kind of thing where there can be no 'middle ground'.

Try to imagine the ring not as a stiff ring, but a series of small closely spaced asteroids loosely joined together by pieces of weak elastic.

This is because no material bond can really withstand too much tension over such an enormous distance.

So this means:
- The ring must not require any force on it to stay in place. Essentially it must be in a stable orbit.
- Being in a stable orbit just means it should obey simple orbital mechanics. In other words, yes it does spin around the Earth, and being in a stable orbit its speed of spin will be determined by the radius of its orbit.
- Would you feel weightless? Objects in orbit are in 'free-fall'. They are at rest in a gravitational field, not accelerating, in other words, you would not experience any/much gravity when in orbit. If you were on your stationary ring, you would float, because you would also be in orbit, at the same speed around the Earth and the same distance above the Earth, so you would not experience any acceleration.

Can it be a ring for a space hook? Yes, but any force on the ring must still be counterbalanced, or the ring would loose orbital speed and come apart. Therefore to maintain a stable orbit, either the ring must increase in rotation when bringing an object up, or decrease down, and conversely decrease orbital radius if bringing an object up, or increase radius if putting one down.

I'm not a qualified physicist either, but did study the subject at university. My take on it is:

Yes. When you say 'completely and relativistically' you mean, "in comparison to my own frame of reference".

There is no 'absolute zero' as everything is 'relative' to everywhere else. This is one of the presumptions of Special Relativity - an objects speed can only be measured in terms of another object. There is no 'absolute frame of reference'.
The 'Vector of the Earth' only has meaning relative to another object. eg. if Earth is moving at a speed of 1000 km/hr, this figure only has meaning if you add 'relative to the Sun'.

Yes, all objects with a different velocity relative to 'us' will be experiencing a slightly different rate of time to us depending on the magnitude of the difference. Although there is a caveat on this - expansion of the universe does not affect the equations of Special Relativity, as space is expanding and additional space is inserted between us. Although the 'coordinates in space' may be moving apart, it is important to note that an objects velocity is different to its position even if the position changes. A distant galaxy that is moving away from us due to additional space being created between us is not experiencing a different velocity, only a changing position, so there is no different frame of reference in which a different rate of time is experienced.

You would find that distant galaxies, although appearing to move away from us at great speed, actually don't have much of a different velocity to us. Therefore their rate of time is not dilated as much as you would expect from our point of view.

You can largely ignore time dilation due to Special Relativity in our own solar system, as velocities for common objects like probes are usually not really that fast. However General Relativity time dilation is a factor for communications, satellites and observations of objects close to mass like planets or the Sun (for example, observations of Mercury or clocks on GPS satellites).

Yeah this is precisely what I was thinking. Back to the inability for printing heads to mechanically deposit material quickly, I can only think of a device like a 'sewing machine' - where you have a stream of ions (the thread), interacting with a beam (the needle) in a highly coordinated fashion at extreme speeds. You can then make very complicated structures without the limitations of the macroscopic scale.

Thanks for the link - MetallicaRap is precisely what is needed. I had a chance to meet Elon Musk before but didn't get to (for a different project), but there may be an opportunity soon so will definitely mention it if it happens! :)

So now all we need is MetallicaRap to 'print itself' including all the materials needed, perhaps with legs and the ability to move around. As Yvonm correctly mentioned though we could have specialised ones that process materials to be fed into a MetallicaRap.

Looking at this we may be closer than we think...

I think it is really hard, because we don't really even know what 'consciousness' is yet. But I have some thoughts on this.

So 'I think therefore I am' comes to mind - let's say my brain is damaged in some way - does this affect my consciousness? Or if a drug changes the way my brain thinks - is my consciousness altered? Maybe then we can organise the different levels of intervention into a spectrum, where we can judge the critical point where consciousness 'dies':

1. My normal functioning awake biological human brain.
2. Normal function asleep biological human brain.
3. Temporary drug induced brain which makes my brain sloppy ('alcohol' for instance)
4. Drug induced brain sleep (anaesthetics for instance)
5. Damaged brain - causing distraction and loss of concentration
6. Very Damaged Brain - causing loss of motor functions, loss of speech, loss of observable function
7. Permanent brain sleep with electrical activity in the brain and ongoing body functions, like a coma
8. Loss of electrical activity in the brain

SO, where does death occur, or loss of 'consciousness'? No one really argues that being drunk you are not 'conscious', but what about asleep? Are you conscious then? Do you suddenly regain 'consciousness' when you awake? Initially I was thinking consciousness was up till 5 on the scale, but perhaps not 6.

And what of distortions by disease or drugs - such as Alzheimer's disease or even mind-altering drugs - are they conscious? Perhaps the threshold is a bit more blurry than we think here, and perhaps we are all conscious up to 8.

A scientific way forward could be defining conscious as electrical activity in the brain, which appears to match observation on 8 of the scale - it is generally accepted that the complex signals that occur in the brain is very difficult to replicate or start again after the 'brain' dies, and is irrecoverable. This begs the question though, that if we can restart the same patterns, does your consciousness suddenly reappear? Maybe then even '8' on the scale is not low enough to determine consciousness, and death is not permanent.

If this is true then consciousness is about configuration: a fleeting moment in time of electrons and photons buzzing from one part of our brain to another. We experience this place now at this moment, and yet if this is replicated somewhere else (no matter when or where) then we experience it again, over there, in that moment. Indeed, maybe the buddhists had it right all along - we are resurrected, just as everyone else, or in everybody, or everything.

So - I suppose my conclusion is then a qualified 'yes', you could experience the same pattern in another 'substrate'. However, it is not you 'now' - you're currently you and will continue to be so until you reach scale '8'. If someone replicates the same pattern as you 'now' then you will also experience that pattern, but not at the same time or place, you will experience it at that time and place. It get's complicated but I don't think our consciousness is then defined solely by our 'substrate'.

It also makes me think that we live in an amazing and unique world - how wonderful it is to know that your configuration of electrons and photons in your brain is moving through the world and experiencing it in all its glory and at this unique place and time. It is a remarkable privilege.

You are considering issues that are right at the core of scientific philosophy let alone physics.

There is certainly a sense that we are 'digging down' further and further the rules the universe has the more we discover. But at its core is still that question: Is there a single rule? This is the 'beauty' that many physicists yearn for - simplicity is often found as the source of complexity and this has yielded us useful results so far.

We are at this time in an unenviable position of discovering many sub-atomic particles, bosons, hadrons and fermions, yet not finding the set of rules that link them. When you think about it: why is there 17 subatomic particles? Why is the sub-atomic world so complex? It does seem rather odd, and the universe at this time seems to be 'cobbled together' from disparate parts. It is a confusing time, because our minds are used to trying to find patterns and making sense by finding rules that determine what we see.

Your Conjecture is a reasonable question to ask: Why should we favour simplicity being no further basic rules to discover that make up our current complex understanding? I suppose we don't know, it would be indeed odd either way: Let's say there is no 'Theory of Everything' it would be equally strange if this would be the case - why indeed would the universe have so many different systems and laws that are unrelated? It seems so unfathomable to us and so we must ask that question: how could this have come to be?

Then we end up right where we started. We need to keep probing, keep testing this and questioning this. In a way, the endless questioning and testing is what science is: and how we keep making discoveries.

I too am concerned over the depleted budgets of governments world-wide, and the pressure (and inevitable further funding cuts) on space programs.

However, I think the era of sole-government funded programs and projects is receding, and already there is a transition either to public / private partnerships or further to full private. The global trend to privatisation is unstoppable and COVID-19 (and it's consequences) I foresee merely accelerates this due to upcoming public debt.

It is not all bad though, private enterprise has much to offer, in many ways more than government could. There just needs to be a commercial imperative behind everything. Space X is in a way already a direct result of NASA budget cuts, with many NASA engineers now simply working for Space X. Space X has the advantage of being lightweight, lean and optimised for a market.

Opportunity exists where governments are actually a customer, not a supplier. This is already sometimes the case. Smart companies see future value in this field, and may actually see more government customers as a result of COVID-19 as governments seek to outsource capabilities to reduce debt rather than do them in-house. This may actually be a 'golden era' for private space development and exploration.

I was overjoyed with the Postponing Heat Death episode - in fact seeing it made me feel good about the universe, I was feeling rather despondent thinking our universe was going to go out with a whimper and in many ways couldn't think of a worse end than entropic heat death.

It is a tantalising possibility to 'intelligently' outsmart the universe and entropy, in fact hearing Isaac say this give me hope when there was almost scarcely none. It is, I believe, better to think that we can outsmart the universe than to think the universe has some kind of amazing, unlikely, natural destiny that saves us all. Now we are self-aware, have the ability to observe it and learn from it, we have the ability to make sure that Heat Death is not for us.

Well done Arthur - defeating entropy really is the Greatest Task of All Time!

I agree that there are interpretations of some evidence that do not line up with contemporary scholarship, however mainstream scientific views are generally conservative (which I agree with) in lieu of being too ready to accept aggressive new theories. I would be cautious to link theories based on few discrepancies with mainstream understanding unless there is an overwhelming weight of evidence to the contrary (Occam's Razor is a good principle here). Current consensus is that the pyramids at Giza, including the Sphinx, are likely built for Pharaohs Khufu, Khafre and Menkaure in the fourth dynasty Old Kingdom, consistent with surrounding pyramids, dynasties and evidence unveiled to this time.

I do agree that there are still many mysteries about Ancient Egyptian culture, which makes the field of Egyptology quite exciting and worth following, and would celebrate equally with you if mainstream views are proved incorrect and consensus shifts.

Welcome Steevo, I love the show too!

There are several issues with this theory:

• There have been numerous studies, including radar, sound wave detectors / sonar, metallurgical analysis and historical studies on these structures as they are prominent and well-visited. None of these have detected anything abnormal in the pyramids to suggest any power source, material not made of stone (barring chambers) nor any sign that would indicate the presentation of the pyramids as other than what historically they are: tombs for pharaohs.
• Keep in mind the pyramids at Giza (of which there are 3 main ones, but half a dozen smaller ones) are not the only pyramids in Egypt - there are in fact dozens scattered down the Nile, many of which not many people know about. They are not all orientated or build the same, reflective of the changing construction technology and theological concepts at the time. Early pyramids were 'stepped', many were smaller or intentionally hidden, one is 'bent' (Pharaoh Sneferu, whom it was widely considered died early so they had to quickly finish his pyramid) and chambers are varied and not as consistent as you think. Also, later Pharoahs were buried in hidden tombs as tomb raiding became commonplace.
• A microwave beam would not accomplish what you suggest. The ship to be pushed would also succumb to the force of gravity, and will therefore follow a ballistic trajectory rather than a 'straight line'. Even if in orbit, it's existing speed to remain in orbit would mean the beam would not be able to have any affect, least of all to get to Sirius.
• A beam would have to penetrate the atmosphere, and be continuously active for some time to deliver enough force to move any sail ship. When I say some time, I mean Sirius is 8.6 light years away - at even an extreme speed of 0.01c it would take 860 years excluding time required to reach such a speed.
• Contrary to belief, EM waves or even lasers (synchronous emissions) are not 'beams', but rather radial emissions that would diffract over distance. A beam to travel the distance to Sirius would require constant refocussing along its path, there is no evidence to support the existence of refocussing devices to Sirius.
• All historical evidence, and current understanding of Egyptian mythology, does not support any kind of extraterrestrial origin or interference. Study Egyptian theology thoroughly - you would be pleasantly surprised how wonderful their culture is. A few pointers:
  -. Egyptian culture spanned over 3000 years with a slow accumulation of theological concepts that unified their culture, but which had consistent origins
  -. Their theology essentially formed around order amongst chaos - they find it a miracle that life is present inside the 'primordial soup' of the universe. That is why the Scarab beetle is so revered - being essentially a dung beetle it creates order from chaos, or life from waste.
  -. Egyptian gods, architecture, art and writing are strongly unified. Their language (being the priesthood heiroglyphics script and writing) is consistently transferrable, with concepts of life, death, the passage of the sun and the moon, all strongly linked in a way that over the 3000 years of existence the culture remained quite constant.

There is no mention of any 'power plant' reference or similar to be supported from the wealth of information we have discovered so far, so I would say this scenario is very unlikely.

And that's the crux of it isn't it? Excluding someone from voting is effectively ruling them out of society. It's a form of excommunication.

Young people are excluded historically as they are seen as incapable of making a decision themselves - it's a fine line though to demand this for others due to their circumstances, education or even attitude. Exclusion from voting due to a perception or lack of 'smartness' means they are not allowed to have a say in who rules them. If that is the case, they may as well not exist.

Keep in mind 'society' is the term here. We are social creatures, we need each other (as equals), even the 'bums'. Excluding them is to exclude a part of ourselves.

Personally I also think the voting age should decrease, and should start right from when a person can put pen to paper, ie. around about 4 years old. Antiquated notions of 'maturity' only occurring at 18 years of age are relics of old traditions, we start making decisions that affect our lives (and have people who make decisions for us that affect it equally as much) right from year 0. And we need to include prisoners, cleaners, uneducated, mentally ill, we need to include all of these people in voting too. To remove the right to vote is to remove their right of existence, the right to influence their rulers, the right to even be considered in any discussion by a government with any sense of consequence.

Here's my take:

1. When people get together they need a system of government - it can't be completely anarchistic.
2. Democracy for all it's failings is still the best and I cannot see it being surpassed in the future even with technology. In fact it would likely be enhanced by it, and even more desirable.
3. The democracy must be based on principle. That means all inclusive, seen as a basic right, and must have genuine regard to people/humans.

So in detail:

1. I am a member of a series of organisations, both commercial and charitable, and have realised that in any situation where more than one person (ie. yourself) is required to do something, you need a system of government. Things get political because of the nature of command, labour, and not just because we are mammals.
   So:
2. Even in small groups, say 2 people up to 5, a default 'subliminal' form of government happens. Either someone takes command, or there is a 'level chat' about what to do and mutual agreement. Ie. A democracy.
3. This would be the same regardless of distance, or of task, or of type of communication. Online communities are the same - although most currently are simply 'autocratic', some do take efforts to be open and 'democratic'.
4. So anarchy doesn't really exist. Either you are in a group with a strong leader, or a strong system of democratic principle, or simply not in a group and by yourself.

5. Can a society exist without 'being in a group?' Only if there is no interaction whatsoever. Which is only possible if either there is no one else, or we cannot relate to one-another at all (either in person, online, physically or mentally).

6. Because I live in Australia, a democratic nation, it was hard to conceive of how 'good I had it', until I started to do business overseas. In non-democratic countries you just don't know what you miss. The ability to have (even the slightest) say in who is in command is priceless. Without it, it is easy to imagine feeling disillusioned, inhibited, or disenchanted or simply repressed. So:

7. For all it's problems, such as ineptitude, incompetence, slowness, bad-decision making, it is still the best option because all or any people in a group won't feel the above way. Otherwise you need to resort to violent means to keep everyone in line. Even a military run society, the threat of violence (or court martial) must be there to prevent mutiny of disgruntled subordinates. People will feel what they feel.
8. Why should we take into account people's feelings? Because historically feelings matter - there would be a revolution if repression or inhibition are allowed to fester. And it's good for society: a less repressed nation tends to make better headway in terms of innovation, progress, communication, and have better economies.
9. Yes people are impressionable, but that's ok. Sure someone who can 'sell' can be President or Prime Minister, but in the end at least people had a say, and later they have another say. Actually, even using the word 'they' in this context has special meaning: you cannot really use this in a communist, dictatorship or feudal type society as there really isn't a 'they' when it comes to talking about people - they are seen as subjects/automatons/labourers/means-to-an-end instead.

10. So can you eliminate this feeling with technology? Yes you could brain-wash or mind-alter people, but is this really beneficial to the government? Might as well not have people then, might as well just be in command of machines, which are likely better at menial non-creative tasks anyway. Or in command of AI's, where you can mould them to your will.

11. So what is it about democracy? Better than the system, or the particulars, of the word is the Principle. For it to be a 'democracy' it really must be completely democratic.

12. So can we have a partial democracy? No. It really is 'all or nothing'. Communism is really a partial democracy - ie. the 4 billion or so people of China don't really matter, they are just effectively 'machines'. The democracy actually is in the Party Room of several hundred individuals, when they elect a chairman. And here, the Party Room is actually the country, and the chairman is the government, elected on a regular basis.
13. The pertinent thing to consider here is: Individuals must be equal for a democracy to have any meaning. Excluding anyone simply excludes them from being considered as an individual - in any sense. They disappear and might as well be a machine.

So what will happen to democracies in the future? Actually, they would get MORE important because they have to. Otherwise it's not a democracy, and would simply be a one-person society, with automatons. But what use essentially are mindless automatons? What is the point of people then? For any meaningful interaction between people they need to be seen 'evenly' or democratically. Otherwise yes - it would be better for a government to simply have machines as its people.

And so even militaries are getting 'flatter'. Why bother with so many hierarchal layers of subordinates, when an individual could simply command a cloud of drones coordinated by an AI? A flight crew in old planes used to have half a dozen officers, but with the advent of better tech, computer systems and even interface, there is now only typically two. And that is so a Captain has a backup in case he makes a mistake or falls asleep, otherwise likely there would only be one person in command, and quite sufficiently. Apply this thinking to a whole population of people - and you realise societies CANNOT be more militaristic, they MUST be more democratic instead.

And when everyone is 'feeling' equal? They become better, at thinking 'outside the box', stuff which AI might not be able to accomplish yet. That is the real worth of having people together, of having a society in the first place. Otherwise we are alone, with a field of mindless automatons doing our bidding below us, with no meaning to our lives.

Yes well they are actually related, although in different ways. Special Relativity relates to 'object in comparison to...', whereas General Relativity relates to 'object is not at rest as it is accelerating, when in a gravity field'.

So imagine a 'photonic clock', ie, 2 mirrors locked in place with a photon bouncing between them. By moving the clock, the photon will need to 'travel' a longer distance and the effect is:
- Under Special Relativity: if you are inside the clock, you notice no difference. If you are outside the clock moving at a different speed, looking at it, it will tick at a dilated rate because the photon will still travel from your point of view at the same speed, so the 'ticking' will be slower.
- If it accelerates, Special Relativity still occurs but at the same rate as the new speed. The photon will begin it's journey as normal in the clock from one of the mirrors, but by the time it gets to the other mirror, the clock has accelerated and thus the distance is larger. So, in regards to Special Relativity, there is no difference between velocity and acceleration. In your example above, if you stop accelerating, your dilation will now remain the same from then on, relative to someone else at a different speed.

Now consider the clock also is affected by General Relativity, if it is in a gravitational field (which all objects in the universe actually is). This is an additional effect, so you could say both forms of time dilation exist at the same time on the clock. But there are some differences:
- The clock is inside a gravitation field, and time elapses differently in the space around mass. This is not a function of the clock's velocity, but rather its location close to mass. Yes, it is experiencing 'acceleration' if it is close to a mass, however to clarify my simplistic post above it is not actually due to acceleration (the acceleration is the manifestation) but more accurately its 'gravitational potential'. So if the clock is on a planet, it looks like it is at rest, however it has 'gravitational potential' so if a hole suddenly appears under it and it starts to fall, this only manifests as acceleration.
- It is this 'potential' that causes the time dilation, different to special relativity's 'velocity'.
- I have omitted the obvious next step here, which is to do with 'spacetime', worthy perhaps of another thread. This explains why dilation would occur in the middle of the planet too, which theoretically there is no 'acceleration' because mass is all around you, yet the dilation would be the strongest here because that is where the field is the strongest.

SO, there are some key differences between SR and GR dilation:
- SR dilation is dependant on someone's viewpoint traveling at a different speed to yours.
- GR dilation is dependant on if someone is closer to mass.
- The difference means that if we all had clocks, in SR, our clocks would be seen as slower by each other, as we are moving away 'from each other'.
- Whereas the GR effect (which is in addition to SR), our clocks are moving at different rates by each if we are in different areas of Gravitational Potential (distance from mass) so this means a clock in orbit, as seen by a clock on the planet, could be faster, and a clock on the planet, as seen by a clock out in orbit, would be slower. This is a different result to SR where both would be slower as seen by each other.

I do agree that the concepts of special and general relativity are hard to grasp. To answer your question we need to explore:

• The nature of ‘speed’ (which relates distance with time). It is as simple as it sounds - how fast something goes over time.
• The nature of 'gravity' - not in that it is a force, but it's effect of accelerating objects together
• The concept of relativity and how it relates to gravity

So let's look at the concepts of relativity first. There was substantial confusion century-before-last as to how observational data was not lining up with theories at the time in relation to magnetic fields and classical mechanics. This distilled down essentially to two observable, seemingly (note) contradictory facts:
- light was measured as being a constant speed no matter where measured, or how fast measurements were 'made'
- otherwise 'classical' motion is indistinguishable no matter where, or how fast you are. In other words it makes sense doesn't it that a ball thrown while in a rocket is expected to behave predictably the same as if I was on the ground and threw a ball.

So how can both be true, if the speed of light from a torch on a rocket is measured the same if I am on a rocket, yet when I observe that same light looking at the rocket it should also be the same speed? Previous logic stated that it should be different speeds when measured from different velocities, but they were the same speed. This was the conundrum (simply put - there was a lot of stuff about electric fields and so on, but don't need to get into detail here).

Einstein reconciled these in special relativity, by saying both are true, because in essence observations were that that they were.
He simply then started to think: if they were both true, what else would be true? The difference is really in concepts of time, velocity and distance. So if the speed is of light is the same, it follows on that time must change to accommodate this truth. The rocket must be experiencing slower time to ensure that the speed of the light from the torch is the right speed when measured by someone on the ground. Hence, time and distance dilation occurs when objects are accelerating or decelerating.

Now: general relativity. Einstein had the same truths about gravity. He was likely wondering what gravity is, as concepts of ‘ground’ is also not really defined. Newton said gravity was just a ‘force’ between two masses, however Einstein was dissatisfied with this. If motion and acceleration is relativistic, why not acceleration due to gravity? Surely there shouldn’t be two forms of acceleration out there in the universe…

Hence two postulates for general relativity:
- no matter where you are or how fast you are, special relativity holds true
- including on a planet - where you are experiencing gravity. Ie. there is no difference between gravity and accelerating. Eg. if you are in a rocket, it is the same as if you were on a planet, you are experiencing the same special relativity effects.

So given these two factors - it holds that when you experience gravity it is the same as if you were in a rocket, you experience time and distance dilation as per the previous explanation of special relativity.

NOW THE IMPLICATIONS: Space becomes very weird (or rather just more complicated). Time dilation and distance dilation occur in relation to mass, not just if they were accelerating on rockets. This means light speed from a torch on a rocket is the same speed as measured from a stationary space station (meaning the rocket experiences time dilation) is the same effect as a torch on a planet also (meaning the location on the planet is experiencing time dilation).

This has matched observations, mainly Mercury, which Einstein proved was experiencing slower time close to the sun than when it was further from it, effectively proving the theory of General Relativity.

There is a lot of maths here that is omitted, and this is ‘thought experiment’ realm only, but is the basic principle - which is acceleration causes time dilation (because light is the same speed no matter where measured from), and gravitational acceleration is the same as normal linear acceleration.

Now another aspect of your question of 'why' relativity is true is more philosophical - and calls into question 'why' behaviours we observe are like this and hence the investigations of black holes and so on which push this theory to the limit - and there are still many mysteries to be solved...

Of almost all the concepts Isaac mentions I found the Self-replicating Machine episode the most tantalising. Can we actually make one?

And it got me thinking, how do you create Mega-Structures, space colonies, mass-produced mirrors or spacescrapers? You need to create a machine to build it for you, but not just any machine: a machine that makes the machine to make it for you.

Or a machine that makes the machine that then makes another in order to make a machine to make it for you. (You get the picture)

So this thread I thought we could jot down ideas on the challenges involved, and any solutions you can think of. For instance I would imagine the following problems, just starting with the basics using today's technology:
- how do you make a machine that makes another one? A 3D printer is the only solution I can think of at the moment. It is conceivable to print one using another.
- however complexity in current 3D printers is rudimentary. They use single pre-made materials and are assembled by hand. We need one that can be printed simply.
- and printing electronics is really hard, so your machine cannot 'think' unless it's possible. In order to print electronics you need materials that need mining and refinement processes that are hard to create and difficult to assemble. So perhaps you have a 'brain' like a central computer, that is manufactured using current-day methods, that 'transmits' instructions simply to 3D printed modules. These modules don't need to think then, they just move and perform tasks.
- they need power. However this could be centralised as well similar to electronics.
- The modules can assemble more modules using an easily workable material - what material I am not sure of, but it needs to be commonly found, easily configurable using only basic gathering and simple bonding techniques. Any material needed can be gathered by gathering modules, heated by heating modules, crushed by crushing modules, all of which must be able to made by the original material.

Which then presents the first question and wall to the concept - what material can be used for the above purpose? Does anyone have any ideas? Also feel free to post other challenges/solutions you could think of too.

I know this forum is yet to find its feet on what is and isn't allowed so I thought perhaps I'll post here and if mods want to move it elsewhere that's fine too.

I just finished seeing Orville's Identity part 2. For those that don't know the Orville, it is essentially now the replacement for what Star Trek used to be. BTW- spoiler alert.

Identity 1 was a great episode, for many reasons. But the main one for me was the questions raised about our tendency to readily Anthropomorphise objects. Isaac, the ship's robot, was being seen by all the human (and non-human) crew as a person, and his blank features seemed to accentuate the fact that we can write any impression of what we think he is on his face.

The episode was great because after know Isaac for so long, where we see crew members treat him as a person, Claire even falls in love with him, in the end he was programmed to betray all in a reasonably logical motive to eliminate all biological life, and it called into question all our thoughts up to that point - Am I guilty of thinking Isaac was a person, entitled to emotion and compassion? What is he, if not what we thought he was? I found myself rerunning old episodes to observe Isaac's interaction with the crew, and suddenly all was cast in a sinister light. Yes he commonly viewed himself as superior intelligence (the crew laughed and assumed it was Vanity) or commented on the failings of his fellow officers (some call it Pride) but in the end these were emotions we projected on to him, he was always what I thought him to be, and I don't know how else to think of him.

Superman (the old 1978 film) was a great movie because it explored a similar theme - this time from Lois Lane's point of view: She fell in love with... what? There was a scene in the middle of the movie where we are suddenly privy to her inner thoughts, yearning or hoping he was what she thought he was (or that he would notice her). This was pivotal as we suddenly realised then that the movie was not about Superman at all (even though he is the star) but actually about what Lois Lane's reality was. It calls into focus the bigger question we all face: Do we really know what is real? When we love someone, what do we love? Are we actually seeing what our minds (and heart) wants to see, and it is not possible to see any other way?

Identity 2 resolved the issues opened so intriguingly in a rather perfunctory manner - I did not think it nearly as successful as Identity 1 because I believe the question cannot be answered as it goes right to the heart of being ourselves in the universe, and seeing it as a microcosm of ourself. In fact, the solution in Identity 2 was that the robots were angry at being mistreated by their makers, however this sidesteps the issue and actually applies an emotion (hate) to logic, which is destroying exactly the point Identity 1 was trying to make. Space battle and all, I almost wanted Isaac to continue to be emotionless, as well as his fellow robots, to explore this further (but I suppose the 'TV Show' can only go so far before it must resort to expected tropes).

So - this thread is mainly then about then: Consciousness and being in this body and viewing the universe. I am here in this body - can I truly know someone? Can you? Does it make it impossible to view the universe from a single point of view (a human point of view) meaning we cannot truly know someone, or something, as we are viewing it only through our eyes, and the very act of observation must be done in the context of human meaning (for example, emotion)? Ie, Isaac is a robot, no more than a bunch of atoms, yet we look at him with meaning, hope, fear, expectation, all the emotions we have - we 'see' him, whether real or not - and do you think you could view him in any other way?

In this thread, post your greatest dream.

I dream: The universe is right now bustling with technological life, that it is crowded, they all love talking to each other and meeting up on crowded stations, ships and planets, it has been for some time, and for some reason however unfathomable we just can't see them.

What's your dream?

This is the very first thread I have posted - I'm a new public user who just drifted in with the wind.