Mordred

Yeah and I agreed with that 2 pages ago. Provided you can quarantee zero reentry.

Funny how you made previous assertions that there is no risk due to radiation for the last couple of pages with others pointing out those errors yet you seem to think I'm incorrect for correcting you. An EMP emits gamma radiation that can cause nuclides Swansont also mentioned that detail previously the 1/r^2 relation is well known. As far citation goes those details ate mentioned in the links I provided had you bothered to read them but when you respond in less than 5 minutes after posting them claiming zero relevance I know you didn't even bother looking at them

Can you answer what happens if a radiated asteroid enters the atmosphere ? We cannot assume you will get 100 percent deflection. Secondly I mentioned you do not get the kinetic explosion that you do in the atmosphere. So you require higher a megaton explosion to get the radiation caused outgassing. The 100 Megatons is simply a random approximation. As far as EMP the 1/r^2 relation is well known and understood it doesn't require citation. Lastly if you read back a page or two I mentioned nukes could be safely used provided you can 100 percent guarantee total deflection

FiNALLY you realize a threat is possible now what happens if that asteroid shatters into smaller pieces and still enters Earths atmosphere ?

https://www.epa.gov/radiation/federal-guidance-report-no-3-health-implications-fallout-nuclear-weapons-testing-through Do you understand the 1/r^2 relation with EMP? Do you also understand that Starfish was only 1.4 megaton. What happens at 100 megatons ? You don't need a citation when simple physics will suffice you can mathematically run the calculations It's relevant ad you do not understand what threat nuclear weapons pose on both longterm and short term effect. I'd you believe there is no threat. Considering I posted those links less than 5 minutes previous of your last response you obviously never took the time to even study them.

Really you can't spend 30 seconds using Google? Fine Here is one such link https://www.cnsc-ccsn.gc.ca/eng/resources/health/health-effects-chernobyl-accident/ This describes the global effect of EMP from Starfish test. https://en.m.wikipedia.org/wiki/Starfish_Prime https://www.osti.gov/biblio/4421057

Why would you believe firing nukes in space poses no threat ? You have EMP so you would need to be further out than the lunar orbit with the average yield warhead. That's a threat. You have an asteroid that gets radiated that if it does enter our atmosphere will contaminate our atmosphere. That's a threat. Stating nukes fired in space poses no threat is plain wrong. The threat is real radiation and EMP is a threat. No amount of denial changes those facts. The radiation from a nuke isn't the same as the radiation from the sun nor cosmic radiation. There is two main categories of nuclear radiation. Those categories are determined by the radiatio halflife . Short half life and long half life. The Short term you get with EMP is damaging but goes away after a few years. The long halflife Euclidean can stay with us for thousands of years. The region around Chernobyl won't be safely habitable for another 20, 000 years how is it that's safe ?

Really and do you believe we have nukes that can just immediately fly out there without using spacecraft in the first place ? It a huge coordinated effort regardless if nukes are used or not. Our nukes are not capable of getting to the asteroid without using spacecraft. So quite frankly your stuck with using spacecraft and the coordinated effort is no different regardless of method. All methods will require a huge coordinated effort. We have produced and tested solar sails as early as 2005. https://ntrs.nasa.gov/api/citations/20050209928/downloads/20050209928.pdf its already been tested as a viable option. You only need a spacecraft with mass to get a gravity tractor. So stating none exist is plain wrong. We have spacecraft so we have the capability at this very moment.

no one is stating that. Its obvious that if the asteroid leads to an extinction event then using nukes becomes acceptable. Where we disagree is that you seem to feel it should be the first option

Hire Spacex immediately to transport as much fuel as possible into orbit. Set up several craft, rather than one to refuel in space with that fuel. Use Solar sails if possible to reduce fuel consumption on those spacecraft. We have plenty of mass already in orbit. One could for example strip material from the International space station to get mass. Then fly to the asteroid and start with the gravity tractor. Those same craft can later be used to impact the asteroid if the gravity tractor doesn't work. Set up the nukes as an emergency option. Get them into orbit and refueled. Use them only if the first two options don't work. You don't need to wait around for these options other than the planning and execution stages. Of course another option is to take the asteroid orbiting Earth and redirect it to impact the incoming asteroid

GR for starters. Ok we don't require to understand that gravity only occurs when you have a non uniform mass distribution. Newtons shell theorem is more than adequate. Take a point at (0,0,0) now have the same amount of mass density everywhere surrounding that point. The force exerted due to the mass density will be identical regardless of which direction you examine. So the sum of force is identical at every angle. (force is a vector). The net force is now zero at (0,0,0) so you have zero acceleration due to gravity. Hence gravity is zero for flat spacetime. The mass distribution is uniform. That's been understood and tested since the 16th century. Its no different for GR or the FLRW metric.

What you assume that ? We are currently researching solutions. Previous research greatly reduces the time for decision making. Even as slow as our Politicians are. Early detection everyone agrees is the key to success.

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.