andrew s

As far as I understand it all interpretations make the same predictions so there is no scientific way to choose. It is a matter of philosophy not science. Regards Andrew

Is that in one or all of your many worlds? Personally, I would hedge my bets. Regards Andrew

Sadly, I spent years trying to understand how our classical reality emerged from the quantum world. Eventually, I came across environmental dechoherence but even this did not solve the measurement problem. I feel it's more subtle than @vlaiv characterisation but I may be wrong. I am now content with my ignorance in many areas. Regards Andrew

If you want to frighten a quantum physicist ask them about the measurement problem. 🤫😉😊 Regards Andrew

@saac the hot topic area would be quantum computing. Also solid state chip design is hitting the limits set by QM. Regards Andrew

I did until a few weeks ago when I retired from serious observing. Regards Andrew

Absolutely, the classical world is our domain. It is the bumps and bruises of our experience with Newton's insights that forged our world. It is the lack of connection to our experience that make relativity and QM strange and mysterious. Open to our prejudice and fantasies. Regards Andrew

We can't all be perfect 😊 Regards Andrew

A legacy few can aspire to. Regards Andrew

I have spent a life time reading about and trying to understand time. Alas I am none the wiser. I have a bookshelf full of tomes on the topic from psychologist, philosophers and physicist each with there own take on it. It is enigmatic in the extreme, you can only measure it via a clock of some sort, it is not an observable in QM unlike space. However, it is the one continuous parameter that spans GR, SR and QED without modification. I had reached a similar conclusion to you that t = 0 does not exist just as the ends of an open interval on the real line don't include the end points. In GR singularities are outside our space time - you are spot on there. In the end I am left with what Einstein's I said "time is what a clock measures " Regards Andrew

Well it also predicted thing we had not seen before. The bending of light by mass and frame dragging are too good examples. It also has an elegant solution to dark energy namely the cosmological constant representing a minute net curvature of space time. (Not all scientists accept it though.) If you follow the literature you will see many many papers on modification or alternatives to GR and or MOND type theories. The test is to find one that explains all GR does and more. We are still waiting. There is no blind loyalty every scientist working in this area would love to get the next Nobel prize for unseating GR. Ripping up the book and starting again is very hard. I think that's what string theorists tried to do. To my mind the issue is we have very good theories that for all practical purposes meet our needs. What we lack is experimental results that force a change in thinking like the MM aeither experiment and the discovery of wave particle duality. Regards Andrew

Here is an example of lens focus Regards Andrew

I have been looking for a reference without success. I think it depends on the scope. The simplest is to move the prisms back and forth but I don't think that is possible with a roof prism design. Regards Andrew PS beat me to it 😊

Moves internal lenes. Think like moving a Barlow in a normal scope. Some camera lenes do the same. Regards Andrew

Absolutely, the only certainty in life is death and taxes, unless your rich enough to avoid the latter.😊 Regards Andrew

Then I fear you will be forever dissapointed. I see no likelihood that we will be able to probe the required energy regime. To expand slightly. Cosmology needs two main components. Firstly, a theory of gravity and second an equation of state. For the extremes required to described the initial state we don't have either. A quantum theory of gravity, if it exists, remains as illusive as ever and as I mentioned we have no way of seeing how matter and radiation behave in these circumstances. Regards Andrew

Can you say why it's so important to you? I don't think it can explain anything we can observe. Things like nucleosynthesis, the ratio of the initial nuclei, is already covered with what we can explain. If you are not concerned with observable things then you don't need a scientific theory types others will do. Regards Andrew

I am in that's ok camp. We can get to about t = 0.0001s of the start which is good in my view especially if you take it as a percentage of the period we do have a good theory for 0.0001s to 13.8 Gyrs Regards Andrew

@Knighty2112 the simple answer is we don't have a scientific theory for what you call the point of creation. We have to stop when the temperature and density are so high that we don't have access to any data about that regime. Regards Andrew

It might be worth listing the key software and kit I used. Software Voyager automation software - also linked to observatory provided weather / roof control The Sky X telescope control and plate solving Astroimagej calibration and photometry VPN access software Kit relevant drivers and access often via browser Hardware Paramount ME II - robotic mount fails safe Atlas focuser - electronic focuser IP power switch - switching kit on and off as needed UPS Back up disc system Electronic filter wheel On Axis Guider Cameras and telescope People Dave and Michelle at PixelSkies - invaluable. Regards Andrew

The best advice I can give is have it at a well managed site. It very easy to remotely turn off your PC rather than restart it. Good to have someone local to turn it back on. Second best have a roof that can shut safely what ever the position of your scope. Regards Andrew

Yes, thinking deeply about simple cases is very insightful. Try changing your frame of reference and have the s (normally) stationary balls heading towards the the m (normally) moving ones. Of course the kinetic energy and momentum in the two frames of reference are different. Regards Andrew

It's a very good example of idealised physics. Another is Newtons cradle. If one just looks at the math you can have solutions in which any one of the balls moves off after the initial impact if you restrict yourself to Newtons 3 laws. You need to add something about rigidity of the balls etc. to get the classical result. I don't think it does as the tangential forces does work on the ball. Regards Andrew PS on reflection there are many cases in physics where there are multiple solutions most of which are rejected as being un-physical even though they obey all the relevant laws and satisfy all the equations.

I have one you can have foc .PM me if your interested. Regards Andrew

But, that us what it is in my view. Look at this. Regards Andrew