Mordred

Oh I didn't miss any point. Nukes are a last resort not the first. If you can divert that asteroid without nukes and still be successful it's dumb to use nukes on the basis it's an easier solution. Using nukes is only acceptable if no other solution is viable.

His point should be obvious. Using nukes and ignoring the risk is foolish

Your right we will disagree. The easiest solution as you state using nukes. Does not mean it's the best solution. If you think it's acceptable to cause harm or risk of harm to our environment simply because using nukes is a simple easy solution compared to other methods that has no risk then I really don't understand how anyone can actually believe that would be the logical choice. Particularly since there is no quarantee that using nukes would be effective in the first place. As I mentioned nukes in space do not work the same as a nuke in an atmosphere. Thr only useful effect from a nuke in space is the radiation and not the kinetic shock waves. That greatly reduces the effectiveness. So now your stuck with using nukes that are significantly more powerful. Starfish was only a 1.4 megaton nuke. We now have nukes in the 50 megaton range. The EMP from Starfish caused global problems due to its EMP. Yet you feel that you can ignore all harmful effects from a nuke on the basis of being a simple easy solution. Great logic there.

If you have the means to deflect the asteroid that does not contain any radioactive material. Then you should obviously choose the Non Nuclear weapon alternative. Using Nukes should never be our first choice. That's realistic as well as smart. Choosing an option that has the potential for long term after effects should literally be the last option. I'm hoping you ate aware that's nukes do not have the same kinetic energy effects as a nuke in our atmosphere ? You don't get the Shockwave kinetic explosion you would from superheating our atmosphere. The main effect of a nuke used on an asteroid is to superheat the asteroid surface using the radiation. This causes outgassing. You don't have an atmosphere to work with. You would likely try to detonate the nuke on the surface but that isn't as effective as a surface discharge on a surface with an atmosphere.

It a clear example of aftereffects of a nuclear test done in outer space. You get fallout. You will also get radionuclides on the asteroid reentry. The entry burnup of the asteroid will release those radioactive components into our atmosphere .

Starfish test proved that we get long term contamination and we can still measure radiation in our upper stratosphere today as a result of previous nuclear tests, incidence, and usage. The Star fish test was 250 km above Earths surface. It's measurable under a category called Global fallout. Nuclear fallout does not go away in a few years or decades

Doesn't mean we should ignore the risk that's simply foolishness. Why compound the idiocy that has occurred in the past with previous tests, and destinations? That's just plain dumb... We know better I would like to think mankind can actually learn from its mistakes. However let's not ignore the political implications. Let's say for example the States attempts to divert some asteroid using nukes. Then have the debris land in number other Countries sat Iran, China, Japan etc. So those Countries now have to deal with the radiated along with the damage from the asteroid. What then happens politically ?

It is a consideration that shouldn't be ignored. Granted where is no or little risk due to distance etc. I would agree but one also must be able to guarantee that the entirety of the asteroid has zero potential of entering our atmosphere once the detonations contaminate the asteroid.

Understood however using nukes is one of the three main researched options the others being high impact devices and gravity tractors.

Here this will help. This paper discusses the application of nuclear devices vs asteroids https://ntrs.nasa.gov/api/citations/20205008370/downloads/Nuclear_Devices_for_Planetary_Defense_ASCEND_2020_FINAL_2020-10-02.pdf The idea is feasible but has its own realm of problems. The paper mentions a few of them including political issues.

It seems your confusion is thinking the FLRW metric for flat spacetime only includes the 3d portion for spatial components. It also includes the time component for 4d spacetime. However for flat spacetime you don't require the Gamma correction between coordinate time and proper time. It's literally no different Than GR for flat spacetime or Euclidean geometry the only difference is the commoving coordinates which is equated via the scale factor "a". The FLRW metric is literally a GR solution.

While not directly a populizer the physicist that got me hooked was Allen Guth with his original False Vacuum inflationary model. I spent the first few years of my studies chasing the process of virtual particle production including many processes you don't hear about today including Parker radiation that was applied to universe expansion. ( that version never went far however Parker radiation now applies to MRI's).

As mentioned its useful for quick references. However one has to be careful on reliability. More often than not you would find good textbooks, dissertation papers and peer review material far more reliable. This is particularly true with subjects that are often seen in our Speculation forum such as ether based theories as one example. I've often seen wiki pages edited to support a particular view point. Thankfully those pages typically don't last long before they get changed again.

Mainly depends on several factors though such as the solar wind poynting vectors, distance and asteroid composition. The hard truth though is no single method works for every possible scenario. Your best off having a range of possible solutions.

You can also use multiple gravity tractors without risk of nuclear fallout.

Might surprise someone but it also is used in string theory.

It does both quite well. Without requiring specific circumstances or distances. That is something that is a major advantage of any theory. If your theory requires specific speeds or distances to show something it usually indicates the idea is lacking. More often than not amounting to numerology. The Lorentz transforms works extremely well in both SR and GR.

You know you really should use the transformations for Lorentz. They are easy to use and work regardless of velocity of the signals. Others have already mentioned that

If you don't need high end graphics, a lot of storage space or a good quality camera on your phone. Then there is nothing wrong with a cheap phone for just phone and text. I use one for work purposes and keep my high end phone for everyday home use.

I doubt that's justification for new particles outside the standard model considering what we do know in regard to electrowesk symmetry breaking occurring less than a second after the BB. So far too much handwriting is in this thread that has little to do with anything physics related.

Yes but the better ones are not cheap however here is a couple of affordable models https://radio-astronomy.org/node/248#:~:text=Beginners usually purchase one of,cost less than %24200 each. Some of the above are kits which seems to be more common to build your own rather than purchase one.

Interesting paper thanks for sharing.

That would explain the essay style.

that makes little sense, we describe our universe with standard model of particles why would you think the initial conditions wouldn't apply the same standard model of particles we see in our present ? (other than particle generations)

Why do I feel this has been copied and pasted ? If so then you need to include the reference source. Not that the OP has ever responded. I don't know if your still seeking answer to these excellent questions but this article describes local vs global symmetries as well as the connections specifically the gauge connections which you have above for \(A_\mu \) https://www.physics.rutgers.edu/grad/618/lects/localsym_2.pdf @KJW Your math savvy enough that the article should answer your questions but if not let me know and I should be able to help if not then this article will also help. Particularly since it includes how local, global, global internal and gauge symmetries are defined mathematically and includes the localized constraint.