Astronomy & Space Exploration

It does work, it just doesn't work to communicate faster than light, and as far as we know never will. We can do some cool stuff with it, just not that.

Are you saying that we can use or even manipulate quantum entanglement.
What kind of cool things can we do with it.
Please excuse my ignorance.
 
Are you saying that we can use or even manipulate quantum entanglement.
What kind of cool things can we do with it.
Please excuse my ignorance.

Entanglement and to a lesser degree, Superposition - have applications in quantum computing, quantum cryptography, timekeeping, and super precise microscopes etc.

Even more mysterious is the recent emergence of temporal entanglement, which showed particles can be entangled across different locations in time, which (imo) has the potential to change physics in the coming decades.

https://www.quantamagazine.org/time-entanglement-raises-quantum-mysteries-20160119/
 
It does work, it just doesn't work to communicate faster than light, and as far as we know never will. We can do some cool stuff with it, just not that.
Quantum entanglement works instantly, surely. I've not read about it in terms of q computing.
 
Quantum entanglement works instantly, surely. I've not read about it in terms of q computing.

It does, but you can't actually communicate with it. You could take entangled quantum particles far apart, and what happens to one would affect what happens to the other no matter how far away from each other they are. But if you try to force one state or another of one particle, to influence the other, you break the entanglement. I might be butchering this, but I think it's something like that.
 
It does, but you can't actually communicate with it. You could take entangled quantum particles far apart, and what happens to one would affect what happens to the other no matter how far away from each other they are. But if you try to force one state or another of one particle, to influence the other, you break the entanglement. I might be butchering this, but I think it's something like that.
I think that I've read something similar. That quantum entanglement works, but if you try to use it to communicate information (that is faster than speed of light) somehow it breaks it. Which is hardly a unique thing in quantum mechanics. The observor is not passive, it directly influences the outcome of experiments simply by observing them (for example the famous double-slit experiment).
 



Susskind really committed to this new direction of combining quantum complexity and high-energy physics. I hope he stays long enough around to see some of his ideas getting explored with quantum computers.
 
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Just finished 'The Black Hole Wars' by Leonard Susskind. A very fascinating read written by one of the brightest minds of our era. In some parts of the book, I felt totally dumb and missed most of the explanations in the string theory chapters. It seems that anything that goes beyond relativity, is too hard to be understood from my brain (I was trying to keep up with some of the analogies in quantum mechanics, but not with a lot of luck, and on string theory it was just hard to follow). Still, I enjoyed it a lot and felt that I learned a lot of things from it.

I would appreciate any recommendation for similar books (please, only from top scientists, not science popularizers).
 
Just finished 'The Black Hole Wars' by Leonard Susskind. A very fascinating read written by one of the brightest minds of our era. In some parts of the book, I felt totally dumb and missed most of the explanations in the string theory chapters. It seems that anything that goes beyond relativity, is too hard to be understood from my brain (I was trying to keep up with some of the analogies in quantum mechanics, but not with a lot of luck, and on string theory it was just hard to follow). Still, I enjoyed it a lot and felt that I learned a lot of things from it.

I would appreciate any recommendation for similar books (please, only from top scientists, not science popularizers).

You shouldn't class yourself as dumb. You should be rather proud of yourself for trying to comprehend such a difficult subject and be well pleased that you have learned something new.

I have tried on a couple of occasions to read (that is the easy part) and comprehend (that is the very difficult bit) books by Stephen Hawking.
But I have to accept that my old brain is better suited to the much easier to understand books by Brian Cox.

Not too many calculations, but explained in a way that I can eventually get to grips with.
 
Just finished 'The Black Hole Wars' by Leonard Susskind. A very fascinating read written by one of the brightest minds of our era. In some parts of the book, I felt totally dumb and missed most of the explanations in the string theory chapters. It seems that anything that goes beyond relativity, is too hard to be understood from my brain (I was trying to keep up with some of the analogies in quantum mechanics, but not with a lot of luck, and on string theory it was just hard to follow). Still, I enjoyed it a lot and felt that I learned a lot of things from it.

I would appreciate any recommendation for similar books (please, only from top scientists, not science popularizers).

Susskind is one of my heros. The black-hole story got new fuel after the "fire-wall paper" in 2012 and many of the prominent physicists in this area are trying to solve it.

I love Susskind's lecture series "The theoretical Minimum".

A number of years ago I became aware of the large number of physics enthusiasts out there who have no venue to learn modern physics and cosmology. Fat advanced textbooks are not suitable to people who have no teacher to ask questions of, and the popular literature does not go deeply enough to satisfy these curious people. So I started a series of courses on modern physics at Stanford University where I am a professor of physics. The courses are specifically aimed at people who know, or once knew, a bit of algebra and calculus, but are more or less beginner

Its heavy at times and he doesn't always succeed at explaining it in terms that are easy to understand. The upside is, that its physics how its done by physicists. He doesn't shy away from sticking to the exact mathematical formalism.
He published "The theoretical Minimum - What you need to Know to start doing physics", where he goes through some of the math that is necessary to understand basic concepts rigorously. Its pretty unique in the sense, that you'll find similar content only in text-books, that are not easily accessible. Its a book for a niche audience, because it certainly has its flaws. I

You should check out Sean Carroll's books. In all honesty, I havn't read them, but he is a brilliant communicator and a serious academic. He just published a fairly new one in 2019 ("Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime").

Otherwise I'd recommend giving "the beginning of infinity" from David Deutsch a look. Its not primarily a physics book, but about philosophy of knowledge. I think that people who are interested in physics would find his approach very interesting. Its probably the best non-fiction book, that I have read.
 
You shouldn't class yourself as dumb. You should be rather proud of yourself for trying to comprehend such a difficult subject and be well pleased that you have learned something new.

I have tried on a couple of occasions to read (that is the easy part) and comprehend (that is the very difficult bit) books by Stephen Hawking.
But I have to accept that my old brain is better suited to the much easier to understand books by Brian Cox.

Not too many calculations, but explained in a way that I can eventually get to grips with.
More like a matter of speech. I think that physics beyond relativity cannot be simply understood in an intuitive manner, and the analogies kind of fail often. I guess even top physicists just get used with the mathematics behind it.

Read Hawking's 'The Grand Design' a few years ago and found it alright, was definitely easier to read than The Black Hole War and felt kind of dumbed-down, though remember learning a shitload of things from it too. Brian Cox is ok for his purpose but was thinking something more advanced.
Susskind is one of my heros. The black-hole story got new fuel after the "fire-wall paper" in 2012 and many of the prominent physicists in this area are trying to solve it.

I love Susskind's lecture series "The theoretical Minimum".



Its heavy at times and he doesn't always succeed at explaining it in terms that are easy to understand. The upside is, that its physics how its done by physicists. He doesn't shy away from sticking to the exact mathematical formalism.
He published "The theoretical Minimum - What you need to Know to start doing physics", where he goes through some of the math that is necessary to understand basic concepts rigorously. Its pretty unique in the sense, that you'll find similar content only in text-books, that are not easily accessible. Its a book for a niche audience, because it certainly has its flaws. I

You should check out Sean Carroll's books. In all honesty, I havn't read them, but he is a brilliant communicator and a serious academic. He just published a fairly new one in 2019 ("Something Deeply Hidden: Quantum Worlds and the Emergence of Spacetime").

Otherwise I'd recommend giving "the beginning of infinity" from David Deutsch a look. Its not primarily a physics book, but about philosophy of knowledge. I think that people who are interested in physics would find his approach very interesting. Its probably the best non-fiction book, that I have read.
Yep, saw it. I would love to do it, but it seems that it needs a huge time commitment, which I cannot give at this stage. Math is okay to be fair, I think that I can keep with it (though not with the math in a rigorous book of quantum mechanics).

Thanks for the recommendations!

PS: Susskind seems such a cool humble guy. He praises everyone in the books (especially t' Hooft and Hawking) like a fangirl, I almost forgot that he is widely considered next to Weinberg and obviously Witten, as the greatest theoretical physicist of his era.
 
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Dark matter solar axions found in Italy?
https://www.bbc.co.uk/news/science-environment-53085260

As it's an "excess events" observation, I'm sure the paper it refers to is going to go through a lot of peer review dissection of its experimental methods as well as its results, and their analysis. Still, it's intriguing. If only from the outsider perspective of how this kind of research is done.
 
Really good explanation of 'The Universe if a hologram' from Leonard Susskind. More or less the same material as in the Black Hole War.

However, I still feel that I don't have an intuitive understanding of 'information', and what is the difference between 'information' and the 'mass-energy'. I am getting used to it though.
 
I am struggling to understand vacuum energy and dark energy. I always thought that they are the same (or well, that the vacuum energy is the reason why dark energy exists), but I guess not.

Wouldn't it be nice if sometime in the future, the physicists would come with some theories that look a bit more sensible?
 
That's one suggestion, but honestly we have no idea what dark energy is.
True. What I mean is that I thought that they are synonyms to each other. I mean, neither of them has been experimentally proven, and both 'exist' just to make relativity equations work (essentially a name for the cosmological constant).

To me the intuition was that the dark energy needs to be there to explain the expansion of the universe, with the vacuum energy being a plausible (quantum mechanics) explanation for the dark energy (essentially, virtual particles with positive and negative energy coming into existence and annihilating each other).

The crazy thing I learned yesterday, is that the mass of energy experimentally measured from quantum mechanics (though no idea how correct this measurement it is, if it is an experimental measurement in the first place) for the vacuum energy is by 120 orders of magnitude smaller than that predicted by some other equations. Yay!

Honestly, I feel that even the smartest people in the world trying to figure these things out are like bacteria trying to understand the plot of Donnie Darko. And laymen like me, probably like more primitive versions of bacteria :lol: Nevertheless, it is the most fascinating thing right there, and I am glad that some of the brightest minds have decided to dedicate their lives to these incredibly hard problems when they could have made a shitload of money by doing economics, or CS or something much simpler but far better paid.
 
I am struggling to understand vacuum energy and dark energy. I always thought that they are the same (or well, that the vacuum energy is the reason why dark energy exists), but I guess not.

Wouldn't it be nice if sometime in the future, the physicists would come with some theories that look a bit more sensible?

Wasn't vacuum energy that which caused the initial cosmic inflation of our universe at the point of the big bang.

We have to always remember that quantum physics doesn't have to be easy for us to understand.
It is what it is, not what we would like it to be.

That is what makes it so fascinating.
 
Honestly, I feel that even the smartest people in the world trying to figure these things out are like bacteria trying to understand the plot of Donnie Darko. And laymen like me, probably like more primitive versions of bacteria :lol: Nevertheless, it is the most fascinating thing right there, and I am glad that some of the brightest minds have decided to dedicate their lives to these incredibly hard problems when they could have made a shitload of money by doing economics, or CS or something much simpler but far better paid.

Agreed. We have only managed to dig 12-km inside Earth's crust. That is the deepest we have gone.

So to understand planets and systems that are lightyears away...
 
I am struggling to understand vacuum energy and dark energy. I always thought that they are the same (or well, that the vacuum energy is the reason why dark energy exists), but I guess not.

Wouldn't it be nice if sometime in the future, the physicists would come with some theories that look a bit more sensible?

This is why we stick to classical physics over here

We were all sorted between Newton and Maxwell and Boltzmann until the rabble rousers came on the scene. I wanted to do a minor in physics until I flipped through a quantum physics book... So many PDEs :wenger:
 
Amazing that there are about 100 billion beyond what's in this photo....



Our universe, or more correctly our observable universe is indeed an astoundingly incredible thing.

Massive beyond belief and full of galaxies including brand new galaxies being born.
And expanding at an increasing rate.

And stars by the hundreds of billions of hundreds of billions. Many if not all with planetary systems.

How can we be alone?
 
Our universe, or more correctly our observable universe is indeed an astoundingly incredible thing.

Massive beyond belief and full of galaxies including brand new galaxies being born.
And expanding at an increasing rate.

And stars by the hundreds of billions of hundreds of billions. Many if not all with planetary systems.

How can we be alone?

I think we're definitely not alone, but it is actually a possibility that life is so absolutely, incredibly unlikely that we might be the only life in our area of the galaxy, galaxy cluster or even the observable universe. Our existence is only proof that it happened once, not that it happens a lot.

Of course, maybe we'll find life on Europa or wherever, and it turns out that life is super common. That's perhaps more scary though, since that raises the question of where all the galaxy-spanning alien civilizations are. Maybe the happy medium is that complex life is so incredibly unlikely that it has only happened a few times in our galaxy. After all, life started pretty soon after the conditions on the Earth allowed for it, but it took billions of years for complex life to happen.
 
I think we're definitely not alone, but it is actually a possibility that life is so absolutely, incredibly unlikely that we might be the only life in our area of the galaxy, galaxy cluster or even the observable universe. Our existence is only proof that it happened once, not that it happens a lot.

Of course, maybe we'll find life on Europa or wherever, and it turns out that life is super common. That's perhaps more scary though, since that raises the question of where all the galaxy-spanning alien civilizations are. Maybe the happy medium is that complex life is so incredibly unlikely that it has only happened a few times in our galaxy. After all, life started pretty soon after the conditions on the Earth allowed for it, but it took billions of years for complex life to happen.
We will 100% find life elsewhere in the solar system. That's where we are from.

Tend to agree with your last few remarks. Which is sad as aliens are an incredible thought.
 
I think we're definitely not alone, but it is actually a possibility that life is so absolutely, incredibly unlikely that we might be the only life in our area of the galaxy, galaxy cluster or even the observable universe. Our existence is only proof that it happened once, not that it happens a lot.

Of course, maybe we'll find life on Europa or wherever, and it turns out that life is super common. That's perhaps more scary though, since that raises the question of where all the galaxy-spanning alien civilizations are. Maybe the happy medium is that complex life is so incredibly unlikely that it has only happened a few times in our galaxy. After all, life started pretty soon after the conditions on the Earth allowed for it, but it took billions of years for complex life to happen.
The universe and everything that happens inside it, for me, is too well put together for Earth to be one of the only planet's in its entirety to truly benefit from it's wonder, It would an incredible waste.. If you look at our own sun, it's practically an engine for life itself, it feels like it's purpose is exactly that. Habitable stars similar to the sun make up a percentage that massively adds up in every galaxy, I think our history of life with the sun will be similar to the fair majority of G type/K type stars across the whole universe, all with their own unique results.
 
Wasn't vacuum energy that which caused the initial cosmic inflation of our universe at the point of the big bang.

We have to always remember that quantum physics doesn't have to be easy for us to understand.
It is what it is, not what we would like it to be.

That is what makes it so fascinating.
Well, it is widely believed that the cosmological constant was higher in the early stages of the universe. Something like 10^(-37) seconds after the Big Bang, it is thought that the universe went from the size of a neutron to a size larger than the observable universe in a tiny amount of time. And then, the cosmological constant has the current value (I believe 119 0 after the decimal point, followed by a nonzero number), which still affects the expansion (otherwise, the gravity should take charge and make the universe collapse).

As far as I know, both the dark energy and the vacuum energy are names/theories for the cosmological constant (which for some time, was thought to be 0, but it seems that is not the case).

This is why we stick to classical physics over here

We were all sorted between Newton and Maxwell and Boltzmann until the rabble rousers came on the scene. I wanted to do a minor in physics until I flipped through a quantum physics book... So many PDEs :wenger:

Yup, physics went from describing the world and being elegant, to making no sense for the laymen and the intuition falling. I actually think that at least in conceptual level relativity (especially special relativity) can still be intuitively understood. But quantum mechanics and what comes after it is just too much for my brain. Honestly, it might be that people just get used to it after being exposed to modern physics, and spending many years on it.
 
The universe and everything that happens inside it, for me, is too well put together for Earth to be one of the only planet's in its entirety to truly benefit from it's wonder, It would an incredible waste.. If you look at our own sun, it's practically an engine for life itself, it feels like it's purpose is exactly that. Habitable stars similar to the sun make up a percentage that massively adds up in every galaxy, I think our history of life with the sun will be similar to the fair majority of G type/K type stars across the whole universe, all with their own unique results.

Okay, but the Sun and the Earth aren't here for our sake, or for the sake of life. They're just here because of physics, so waste doesn't really come into it. There are undoubtedly a lot of planets out there in habitable zones of their systems, but that doesn't mean life happens. It might mean that, but we simply don't know. Life could be extremely unlikely, and though we might wonder at what a coincidence it is that it happened to us, it's one of those "we're only around to wonder why it happened to us because it happened to us" kind of things. If it happened to someone else, they would be the ones wondering why it happened to them.

I don't know, it's all pure speculation obviously. I hope there's life, and I think there is, but you know.. there might not be. We'll just have to wait and see.

We will 100% find life elsewhere in the solar system. That's where we are from.

I mean... maybe? That would be cool, there's just not any evidence for it. There's not any evidence against it either I suppose, so it's as good a thought as any.
 
Sure there is life elsewhere. But:

- Is as advance as us?
- It survived cosmological events in their area ( meteors, is their star(s) lose his constant light/heat, black holes)? Maybe the universe is designed to not give enough time to a life form to evolve enough to get further away than their solar system due to cosmological cataclysmics
- Are they made like us (carbon based)?
- They perceive reality and the universe as us?
- Can they or will be ever life that will be able to travel as much to meet us? is that technology even feasible? (Most important variable IMO)
- The combination on some of them might make their moral, conduct, etc incomprehensive by us (and viceversa) and consider us as alive as we consider rocks to be alive?

And I am sure there is more questions like that
 
Okay, but the Sun and the Earth aren't here for our sake, or for the sake of life. They're just here because of physics, so waste doesn't really come into it. There are undoubtedly a lot of planets out there in habitable zones of their systems, but that doesn't mean life happens. It might mean that, but we simply don't know. Life could be extremely unlikely, and though we might wonder at what a coincidence it is that it happened to us, it's one of those "we're only around to wonder why it happened to us because it happened to us" kind of things. If it happened to someone else, they would be the ones wondering why it happened to them.

I don't know, it's all pure speculation obviously. I hope there's life, and I think there is, but you know.. there might not be. We'll just have to wait and see.
This is true. What is also true, is that the universe seems to have been 'designed' to support life. I am not talking with regard to religion, but for the anthropic principle. There are just so many universal constants, that if either of them would have been slightly off (and by that I mean by 1 billionth of 1 billionth of 1 billionth ... of 1 percent), life doesn't exist. Heck the unvierse might not exist at all if they are slightly different. Of course, a multiverse with 10^(500) universes on it, each with its own constants means that some of the universes will support life, and then obviously we would happen to be in a supporting life universe. But the evidence for the multiverse is as low as that for the existence of God.

I think this is one of the most challenging questions in the history of science. Why these almost random-looking constants are exactly as they should be in order to support life.
 
Okay, but the Sun and the Earth aren't here for our sake, or for the sake of life. They're just here because of physics, so waste doesn't really come into it. There are undoubtedly a lot of planets out there in habitable zones of their systems, but that doesn't mean life happens. It might mean that, but we simply don't know. Life could be extremely unlikely, and though we might wonder at what a coincidence it is that it happened to us, it's one of those "we're only around to wonder why it happened to us because it happened to us" kind of things. If it happened to someone else, they would be the ones wondering why it happened to them.

I don't know, it's all pure speculation obviously. I hope there's life, and I think there is, but you know.. there might not be. We'll just have to wait and see.



I mean... maybe? That would be cool, there's just not any evidence for it. There's not any evidence against it either I suppose, so it's as good a thought as any.
It's a very speculative topic like you say, but I don't think life is just a byproduct of the production of energy from the sun/universe. When you look at the fundamentals of physics and science in general, it is all designed to support the existence of it. It sounds a bit wacky and almost religious, but it seems the purpose of the universe/light/gravity is to ultimately create and support the existence of life.
 
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It's a very speculative topic like you say, but I don't think life is just a byproduct of the production of energy from the sun/universe. When you look at the fundamentals of physics and science in general, it is all designed to support the existence of it. It sounds a bit wacky and almost religious, but it seems the purpose of the universe/light/gravity is to ultimately create and support the existence of life.
Definitely. And to go a bit further, the 'axis of evil' thing seems to give some significance to the solar system.

It is all weird!