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The attenuation is less than 50% at the wavelengths used by solar panels.

What’s the practical solution to heat radiation that doesn’t require running your chips at infeasible temperatures?

If you try multiplying two numbers, say 4 digits each, using the standard grade school technique, you'll see that you end up writing the digit-wise product of each number, with a shift (adding a zero at the beginning) for each digit, followed by a sum. This is literally just a convolution operation over the digits (this is because secretly writing a number in base B is equivalent to expressing a polynomial evaluated at the integer B, and multiplying polynomials is a convolution over the coefficients). By the convolution theorem, this O(N^2) time operation can therefore be accomplished in O(N logN) time by doing multiplication in frequency space and then transforming back. This is because the Fourier transform is O(N logN), via the FFT, and multiplication is O(N).

I just looked up the answer to my original question - the Fourier trick is notionally only O(N logN), but because the FFT takes you from integers to floating points, as N gets larger you need to encode more and more bits to achieve enough precision to yield absolute errors <1 after doing both Fourier transforms. The need to encode those extra bits tacks on another logN, taking you to O(N log^2 N).

I was under the impression that because the grade school technique we learn is really just convolution over the digits, the fastest algorithms achieve o(n logn) via fourier transforms. Is that not the case?

I think the biggest (and, in my opinion, obvious) problem with this argument is that it relies on time having no value in the eyes of the consumer (or, equivalently, that the seller believes this to be the case). A consumer 5 years after a game's release may only purchase said game at marginal cost, but the consumer 1 day after release is willing to pay a premium to receive the product. There really doesn't seem to be any logical support for the component of the conjecture that says "because the price may eventually settle to the marginal cost, it must immediately settle to the marginal cost". There is obviously a time-constant present

> fully reusable rockets are going to be one of the most important engineering achievements in human history

The number of implicit biases, assumptions, and unsubstantiatable assertions packed into that extremely confident sentence is frankly kind of impressive.

We have no idea how important reusable rockets will end up being, because we have no idea of what the future potential (economical or otherwise) space travel will have. Even Musk’s oft repeated (supposed) personal motivation for space travel (“protection of the species”) will ultimately hinge far more on other, far more important (and as of yet unrealized) technologies than reusable rockets.

Not to mention your implicit comparison of reusable rockets to literally every other extant technology. I mean really - transistors? The written word? RF comms? Indoor plumbing??

That’s because, as the article explicitly states, this post is by walletwallet’s developer

> A Starlink satellite uses about 5K Watts of solar power. It needs to dissipate around that amount (+ the sun power on it) just to operate.

The “+ solar power” part is the majority of the energy. Solar panel efficiency is only about 25-30% at beginning-of-life whereas typical albedos are effectively 100%. So your estimate is off by at least a factor of three.

Also, I’m not sure where you got 5 kw from. The area of the satellite is ~100 m2, which means they are intercepting over 100 kw of bolometric solar power.

Useful, extractable energy comes from a temperature differential, not just temperature itself. Once your system is at temperature equilibrium, you cant extract energy anymore and must shed that temperature as heat

This argument assumes that you only need to radiate away the energy that the solar actively turns into electricity, but you also need to dissipate all the excess heat that wasn’t converted. The solar bolometric flux at the earth is 1300 w/m2, or 2600 for 2 sq m. That works out to an efficiency of ~20% for your home solar, and your assumed value of 750 w yields an efficiency of ~30%, which is reasonable for space-rated solar. But assuming an overall albedo of ~5% that means that you were only accounting for a third of the total energy that needs to be radiated.

Put another way, 2 sq m intercepts 2600 w of solar power but only radiates ~1700 w at 350 k, which means it needs to be run at a higher temperature of nearly 125 celsius to achieve equilibrium.

Thats not how big-O notation works. You don’t know what proportionality constants are being hidden by the notation so you cant make any assertions about absolute runtimes

In most places in the US (california being a notable exception) taxes are reassessed regularly based on market conditions. In some areas this can result in the property taxes rising to an appreciable fraction of the mortgage rate - or in the GPs case, what the mortgage would have been, if they hadnt paid it off already.

Thats like saying the grocery store is ok with me eating some of the grapes while I shop so they must be ok with me walking out without paying for my groceries.

I’m not trying to be obtuse here. I really want to understand some sort of reasonable moral justification for actively avoiding paying for a service that you are using / circumventing the mechanism by which the business makes money.