34546 Thanks guys!  How do you feel about Thorium? I feel quite positive about it! This PBS Space Time episode has a great overview of the technology and what makes it so much safer, while also reducing the lifetime of radioactive waste that is generated. ElulEJruhRQ There is also this video which ...

Good info and good sources. Nuclear is indeed cleaner and by sensible metrics less costly to the environment and human life than coal and most other methods of producing energy. It's just that if it goes wrong, it can go very wrong and the impacts are harder for the public to miss (also easier to ov...

34536 Like if you're flying fast towards a cliff, and a sound overtaking you from the behind will have its frequency shifted down, and when you hear the echo from the cliff a bit later, the same sound will be shifted up. Yes! Excellent analogy. 34534 hmmm this sounds a lot like how the sound of a t...

34528 What I don't quite catch here is that the black hole could make me see the redshifted things behind me in two different directions, once directly (behind) and once bent around the black hole (in front).  Therefore I would expect bands. Aye, I think I see your confusion, and it's my fault for ...

34524 If we were approaching a ring singularity in a spinning black hole would the tidal forces be as strong near the center? I believe that depends on the mass and the spin of the black hole. One could imagine a combination such that the ring singularity may be passed through with negligible tidal...

34525 Wat what do you think of all this vaccine being available before the new year talk? Depends what is meant by available. Some number of doses may be available for emergency deployment, I hope for the health care workers and the most vulnerable, but probably not for the general public, let alon...

As evidence builds that COVID-19 can damage the heart, doctors are racing to understand it.   Just another reason that everyone should really try to avoid getting this disease. A growing number of healthy people who recover from even mild cases of COVID-19 are later being found to have lasting prob...

34514 But approaching the black hole behind and in front get somewhat smeared out, so would there rather be bands of red and blue? Objects behind you will be aberrated into view ahead, but there won't be bands of color. Just a smooth transition from redshift behind to blueshift ahead, as illustrate...

34512 If you were already approaching the black hole close to the speed of light, so stuff in front of you should be blue shifted and stuff behind you should be red shifted, what then when diving into the black hole? In this case your journey to the center will be shorter (no surprise), and the bla...

34510 Since you would reach crazy speeds relative to the background stars before the event horizon is crossed, why don't we see any redshift? Great question! Your speed relative to the stars would indeed be enormous when falling into a black hole. In fact, it is equal to the speed of light at the m...

34507 Is there a way to simulate a voyage into the interior of a supermassive black hole using SE? Not currently. It would take a more complicated relativistic rendering system, which would also likely be very slow and computationally expensive. For now, SE calculates the view of a black hole accor...

34501 But what about black hole cosmology, which states that the universe isn't a black hole but exists inside a black hole inside a larger universe? ¯\_(ツ)_/¯ It's a cool idea, but it doesn't yet provide us with a good way to find out if it is correct. The practical falsifiability is lacking, whic...

The smoke plume recently reached the jet stream, and is rapidly sweeping eastward. It now covers the entire northern US and southern Canada: https://i.imgur.com/bPrbnWN.gif I would not be surprised if people in northern Europe notice it in another few days. Conditions here meanwhile are slowly impro...

JackDole , okay, I define all my constants the same as yours and tested it out. Your formula looks right except there was a factor of 2 missing within the square root.  The correction is: gBH(r;M) = (G*M*mSol)/r^2*1/(sqrt(1-(2*G*M*mSol/(c^2*r)))) Using 1.5e12 solar masses for the black hole, I get ...

34494 Then it seems right. Right on the horizon, about 0.14 parsecs, I have 10.67590883 g. Much the same as in your illustration. Mmm, that's not right.  For 1.5 trillion solar masses and exactly on the horizon, Newton predicts 10.17m/s 2  or about 1.03g, while in reality and according to general r...