Thorondor

Nothing is completely foolproof, but LORAN was much, much more resistant to jamming than GPS. GPS satellites orbit over 20,000 km from Earth and transmit at very limited power (less than 50 W). That makes it easy to overpower their faint signals. On top of that, GPS operates at a frequency over 1 GHz which means you can broadcast a jamming signal with a small antenna. LORAN was the opposite. It used low frequency, extremely high power signals transmitted from stations relatively closer to the receiver. Those design choices made it less precise but vastly more robust.

Air-independent propulsion.

The US is the second largest textile exporter in the world. Sources: https://ncto.org/facts-figures/us-textile-industry/ and https://www.trade.gov/selectusa-textiles-industry It's true that a significant amount of that is fabric and fibers, and most of the clothes sold in the US are not actually sewed here. But on the other hand, US companies also show up in other places in the clothing supply chain as well - American fashion design and marketing contribute a lot of the final value of many clothing items sold here and overseas.

> Can you provide the source? In the WTO's broader medical goods category, Germany actually exported slightly more than the US in 2022 ($202.6 billion versus $189.6 billion), so such a huge difference in a few years?

Sure, these are my sources. World Bank (2023): https://wits.worldbank.org/trade/comtrade/en/country/ALL/yea... Observatory of Economic Complexity (2024): https://oec.world/en/profile/hs/medical-instruments

> China accounted for approximately 44.2% of the 104 new molecules in 2025, compared with 26.9% for the U.S. and 15.4% for Europe.

Source for this? My source was Citeline's 2026 annual review at https://pulseforinnovation.org/by-the-numbers-citelines-rd-a... which states:

> Findings from Citeline’s latest report, Pharma R&D Annual Review 2026, highlight the continued U.S. leadership in the life sciences ecosystem... The U.S. leads all other countries, currently advancing over 11,600 medicines – more than half of medicines in development worldwide.

> I will just give 3 examples

In general, I was referring to "major industries" in the sense of economic categories, as defined by (for example) the UN: https://unstats.un.org/unsd/publication/seriesm/seriesm_4rev... Here shipbuilding is considered to be part of "manufacture of other transport equipment." I admit my wording was a bit imprecise; if you are going down to the level of specific products like ships or solar panels, clearly it will be easy to find examples of things that the US does not produce on any significant scale. Nevertheless, a few comments on your examples:

> China completed roughly 91% of the world’s shipbuilding tonnage in 2025

Source on this? 91% is a lot and I can't find anyone else making this claim. However I'll concede that the US is far behind China, South Korea, and Japan in shipbuilding.

> [China] holds more than 80% of solar module manufacturing capacity

You are correct that the US has "only" 60 GW of domestic solar module production capacity according to https://www.utilitydive.com/news/onshored-solar-supply-chain... However, as context - the only purpose of producing solar modules is to generate solar power, and the US was the 2nd-largest producer of solar power in 2025 according to https://en.wikipedia.org/wiki/Solar_power_by_country Surely that makes us a leading player.

> [China] produces more than three quarters of global batteries

True but the US was the 2nd largest producer. In battery cells, we have an estimated capacity of 96 GWh in 2026. https://poweralliance.org/2026/03/18/american-energy-storage... Likewise in lithium-ion batteries: https://elements.visualcapitalist.com/ranked-the-top-lithium...

> My impression is that, if China surpasses the US in AI development, there will basically be nothing that the US does better than the rest of the world--except for military spending

This comment is stunningly out of touch. The US dominates finance (overwhelming lead in assets managed, stock market capitalization, trading volume, and basically every other metric); space launch (about 85% of all mass placed into orbit); medical devices (exports nearly 2x the second largest exporter); and pharmaceutical research (more active clinical trials than any other country, near-universally ranked as the top producer of major pharmaceutical innovations, world-leading survival rates on many cancer types). We are the world's leading producer of both oil and natural gas. We manufacture the world's most advanced jet engines, precision agricultural machinery, and measurement instruments. We design the world's most performant CPU's and GPU's. Despite having only 4% of the world's population, there is literally not a single major industry where the US is not a leading player.

There is no doubt that China is a serious threat to US global leadership, and they have already surpassed us in many areas. But that doesn't mean the US is behind overall. We still have a lot of strengths and we have every reason to hope for continued success in the 21st century.

Weights should not be 0 (at least not frequently) but in a ReLU-based neural network, activations are 0 pretty often. You're absolutely right about die area though.

Hardware engineer here. Special casing the multiply by 0 and multiply by 1 paths is harder than it sounds. In software, the cost of adding special cases is simply performance. You're adding more instructions that execute in sequence on a CPU that already physically exists. Doing this for your multiply case is worthwhile because the speedup is large for 0 and 1 while the cost is not that large (relative to the time taken for the whole multiplication operation) for other values.

Hardware is different. Every operation that can be performed in hardware by a chip needs dedicated circuitry. Special casing 0 and 1 means adding at least OR reduction on each operand and a dedicated multiplexer for every bit of the output. Those transistors use power even when they're not in use (leakage power is a huge issue on modern semiconductor processes). They also degrade timing by adding more gates on critical paths through the multipliers. (The timing issue here is that all operations that happen between one flip-flop and another flip-flop need to finish within one clock cycle.) And unless there are whole blocks of 0's and 1's (this does happen in certain neural networks), you typically won't see a direct speedup anyway. In software terms, the matrix multiply is scheduled as many parallel operations that cannot be accelerated much overall by skipping a few operations in some "threads."

All of this makes zero skipping a nontrivial topic. People do still try to do it but it needs serious consideration as, depending on the application, the case is rarely one-sided.

Yes, but a car can't use electricity at 1 MV and converting the megawatt back to something lower than 1 MV still produces a lot of heat.

A mirror virus would not be able to infect normal cells. Viruses depend on (chiral) host cell machinery such as ribosomes to reproduce.

> Take a look at the structure of something like CMOS and you’ll see why running transistors in anything other than “on” or “off” is definitely not energy efficient. In fact, the transitions are where the energy usage largely goes. We try to get through that transition period as rapidly as possible because minimal current flows when the transistors reach the on or off state.

Sounds like you might be thinking of power electronic circuits rather than CMOS. In a CMOS logic circuit, current does not flow from Vdd to ground as long as either the p-type or the n-type transistor is fully switched off. The circuit under discussion was operated in subthreshold mode, in which one transistor in a complementary pair is partially switched on and the other is fully switched off. So it still only uses power during transitions, and the energy consumed in each transition is lower than in the normal mode because less voltage is switched at the transistor gate.

The main issue is that when objects spin really, really fast, they tend to explode due to centrifugal force.

The tensile stress on a spinning round, homogeneous object is p * r^2 * w^2, where p is density, r is radius, and w is angular velocity. Using your numbers for a steel cylinder with density 8 g/cm^3 gives a tensile stress of (8 g/cm^3) * (5 mm)^2 * (2pi*1 MHz)^2 = about 8 TPa which vastly exceeds the tensile strength of steel or any other known material. Using cows connected by ropes would be even worse because the enormous centrifugal force would be borne by only a small rope.

You're ignoring the units of G. The gravitational constant has units N * m^2 / kg^2 = m^3 / (kg * s^2). That contains a length unit raised to the third power, which exactly balances the factor of 8 that you identified.

Landauer's limit assumes that computation uses a thermodynamically irreversible process and erases bits of information. This is not necessarily true for all useful computers [0]. So theoretically speaking, it's not impossible to create an adiabatic microprocessor. Skepticism is definitely warranted though.

[0] https://en.m.wikipedia.org/wiki/Reversible_computing

To prove that it's possible to buy ads targeted on microphone audio. If this kind of targeting was really as widely available as the article implies, a journalist would be able to do it fairly easily and write an article about it.

In my experience, there are a lot of applications that are "trivial" enough that PID works fine. I'm reasonably comfortable with state space modeling for systems with more variables. But OK, I'll bite - always open to picking up something new. What resources would you suggest for someone who wants to learn more about nonlinear controls?

Nuclear energy is hardly the only power source that has made an entire city uninhabitable. The Banqiao dam failure flooded 30 cities and affected over 10 million people. https://en.m.wikipedia.org/wiki/1975_Banqiao_Dam_failure

Then there's Centralia, PA, which was turned into a virtual ghost town by a coal mine fire. https://en.m.wikipedia.org/wiki/Centralia_mine_fire

And we're not even considering the effects of global warming here. Sure, nuclear has risks, but our civilization needs energy and nuclear has proven to be one of the least risky ways to produce it.