Recent content by contrarian

There is clearly a hot debate on the BBT. Here are some comments from a cosmologist as to why there is such debate, based on JWST data : “The early universe was bathed in a thick fog of neutral hydrogen,” explained Roberto Maiolino, a team member from the University of Cambridge and University...

All of what you are posting is open to debate, and I am not going on with it endlessly. Like you, I have not kept up with some of this, but there are variations in models now that these early galaxies have been found. I have no interest in searching for references about low mass stars forming...

I discount certain aspects of it. The recent data from the JWST might provide some evidence to support this. I keep reading about how the youngest galaxies (<300 mys) shouldn't be there based on BB theory, so there is a little more than speculation to question the absolutes of the "old" BBT. Not...

What is the evidence for this? None. Smaller stars have been forming since the cosmic dawn, and cranking out lots of heavy elements by SNs. And they are still forming today, without Pop III stars. SN 1987A rewrote the book on core collapse SNs. Before, they were thought only to occur from old...

All larger stars produce most of the natural elements that we know of, and they have been doing this for billions of years. These elements are made either from direct fusion events, or from core collapse SNs. Black hole and/or neutron star mergers likely contribute some of the heavier...

Primordial black holes are also postulated to have formed very early after the BB (before or during the formation of H and He), and could have been the primary seeds of galaxy formation, avoiding any need for Pop. III stars in this regard. These PBHs could have formed with a wide range of...

One possible reason is a hardware problem in one of the engines may have caused excessive "harmonic response" in the upper stage. This apparently resulted in stress on the engine structures, leading to a propellant leak in the attic, which lead to failure of this stage. In the final analysis, a...

I understand your mistake. It happens to me from time to time, sadly.......... And I understand the use of so many engines. But it makes for a much more complex assembly, which may be why they are having so much trouble. It is established that fuel leaks are the primary cause of the last three...

It actually burns liquid methane, which is very cryogenic and much more difficult to handle than propane. Also of concern are those 33 engines with the first stage. The more engines, the greater the risk of failure due to defects. The Saturn V had only five engines, without a single failure...

The Saturn V had no failures on its learning curve. Just now reading that the second and third stages of the Saturn V burned H2 and LOX. The Starship burns methane and LOX on all stages, and is apparently on a steep learning curve. The last three failures are largely attributed to fuel leaks.

Is SpaceX's Starship methane fuel a problem with all these failures? Google AI tell us that "Methane, when mixed with liquid oxygen, can be prone to leaks and fires, especially if the system isn't designed robustly." No doubt they are trying a "robust" system, but the results are not looking...

And that is part of the problem. The reactor is going to be assembled on the Moon. It is not going up in one go. The problems which might occur are during a launch failure or unexpected re-entry. Again, it all depends on how the fuel rods are made and stored, and how much fuel is in the vehicle...

Hard to imagine fuel rods staying intact during a de-orbit. Unless they are designed to survive (unlikely), they will disintegrate. The problem of course is where all this debris lands, and how much they originally contained.

If the rods disintegrate on launch (very likely), they would spread radioactivity over the "landing' zone, which could pose hazards to anything living there. If they stay intact, you are right, they pose little trouble.

Good to see these two spending a lot of money on space exploration rather than on weapons of war. China is doing too much of that right now, and Russia are trying to. The biggest initial concern on this project is/are explosion(s) of the heavy-lift rocket(s) carrying all that radioactive...