dplavery92

"as the Xenon built up" should read "as the Xenon burnt off*"

>The Chinese are still struggling to successfully copy previous generation Russian designs

This is certainly not true. If anything, the Chinese are very successfully copying current generation American designs.

https://en.wikipedia.org/wiki/Chengdu_J-20

https://en.wikipedia.org/wiki/Shenyang_FC-31

This is compounded by the fact that the boron control rods at Chernobyl were tipped with graphite (to increase volume/displacement at lower cost), so that when the reaction started to run away as the Xenon built up, the operators attempted to SCRAM, but the graphite tips on the leading edge of the control rods acted as neutron moderators before the the boron was in place, further accelerating the reaction and causing the reactor explosion.

I don't think he did abstract it that way; it's one point in a more holistic picture of Zhu's firing, which largely speaks against Zhu's own assertion that [investors such as Shah and Bicer] would be more comfortable with a white CEO:

"You’re just pattern matching,” Zhu recalls telling them. “Your last 20 CEOs who went public, they were probably all Caucasian guys.”

Note again that the same board replaced Zhu with his east-Asian partner, who also supported Zhu's ouster, and that each of the investors in question had funded other major start-ups with east-Asian CEOs.

True, but it's an incident he only informed the board (including new board members) about in late 2020, and is one aspect of his communication with Bloomberg Business that the board told him to stop for 10 months before being terminated.

>especially in convolutional/correlation neural networks, which often make use of the convolution theorem to do the convolution

Is this true? With the learned filters being so much smaller than the input imagery/signals, and with "striding" operations and different boundary conditions being wrapped into these algorithms, it doesn't seem like a natural fit.

The fact that your previous 6 flips were all heads was an unlikely outcome, but the coin has no recollection of what just happened and doesn't "care" about the past when you flip it again. The maths term for this is to say that each coin toss is "independent." I would not bet that you'd get another 6 heads in a row, but I would bet that the next coin flip will be heads.

That's strange, given that the Kelly criterion maximizes the expectation of the log of wealth--that is, it's maximizing over multiplicative percent gains in a scenario where you can go bankrupt.

Personally I had grown out of that habit a semester or two before undergrad QM (though "Modern Physics" and "Experimental Physics" were another story...) but there were still some hangers on. Maybe 1-3 in a class of 20-25? Neither the norm nor unheard of. From that point on the statistics were probably about the same in grad school.

I hard disagree with you, though I think there is something important about acknowledging what you'll ever be able to see with the naked eye. DSOs are going to be fuzzy white spots, no matter how much aperture you have. You will never get the colorful panoplies of astrophotos.

That said, I think you're underselling the experience of seeing these objects with your eyes in real time, and overselling the accessibility (in price and in difficulty) of setting up astrophotography.

That's the lynchpin that guarantees Russia will retaliate, but it's Ripper's unchecked moments of control at SAC that set the whole ball rolling, and Slim Pickin's is cowboy-riding that bomb down to the ground whether Russia has an AI or not.

> Seems to me the field is wide open for someone to come in and solve it using off-the-shelf hardware.

Solve what?

You certainly wouldn't be the first to build a motorized tracking mount for astrophotography. There are plenty of existing products for manually-aligned star-trackers, and several still for "autoguiding" trackers that use the position of fiducials in the image plane. (These can use either a mirrored split in the optical path of the main imager "on-axis", or use a piggy-backed guidescope imaging system on the same mount.)

Check out high-gain, high-sensitivity imagers like the ZWO ASI290MM Mini, controller like the ZWO ASIAIR Pro, and tracking mounts like the iOptron CEM25P or Sky-Watcher EQ6-R Pro.

These are expensive, carefully engineered solutions, though. They don't really exist in the same market space as Dobsonian telescopes, and it wouldn't make any sense to make those tracking solutions twice as complicated and twice as expensive using by non-equatorial mounts.

> the thought of a Kubernetes cluster autonomously flying around with nukes scares the fuck out of me

I get this, but I also wonder if the same kind of bugs or unintended behavior in a software system aren't just as likely in the protocols, procedures, and chains of command we build for humans to deploy that weaponry. You've got AI doomsday (a la "War Games") on one hand, and bureaucratic doomsday ("Doctor Strangelove") on the other.

If you want to get into astrophotography, the phrase "entry-level" should probably not be in your vocabulary any more, though.

Of course, optics are only half the battle. The other half is with the hardware all around them: plastic tripod leg clamps that slide, plastic baseplates that crack behind collimation screws, alt-az mounts that shake like a branch when you try to slew, and everything in-between.

I think you have the right mentality about making sure you enjoy the hobby and what to understand how to use a scope, but maybe the better advice (modulo COVID precautions) is to seek out star parties or observatory public outreach events. These are free, aren't fraught with the pitfalls of cheesy equipment, and will show you as much as you can expect to see with a scope given several years of experience and several thousand dollars of investment. Was it inspiring or disappointing? Would you drive an hour out of your way to stuff your hands in your pockets and do it again?

I think 6" is still pretty manageable for most people--you can probably fit it in the trunk of a sporty two-seater car. It's really only when you get to 10" and beyond--telescopes that are probably not a good "first scope" purchase for a variety of reasons--that the Dobsonian becomes a beast.

This is the sort of thing where darker is always better, but John Dobson started a movement around "Sidewalk Astronomy" in the 60s and 70s in San Francisco with this very telescope design. I'm sure the light pollution has gotten worse since then, but the moon, the planets, and perhaps a few brighter Messier objects will still be within reach. It's a big sky and there's a lot to see.

I agree with this suggestion, but will add that you should get an affordable tripod to keep your image stable. (Your linked articles, of course, have plenty to add on this topic.) The lucky point here is that binoculars are small enough, light enough, and low-enough magnification that you can get a pretty cheap tripod without it ruining your experience. You can break into the hobby with a pair of 25x70s and tripod for like $150.

Telescopes need a mount and tripod (or Dobson-style mount) too! The price and barrier to entry with binoculars is smaller than any telescope you can't fit on your table top, and I think they're a great way to wet your feet and make sure you're willing to drag something out into the cold late at night.

I'll glom on this only to add that while building your own reflecting telescope is valuable as a fun project or an educational exercise, you are unlikely to save much (if any) money doing it. A lot of John Dobson's "Sidewalk Astronomer" guidance comes from a time in Southern California where it was easy to find discarded porthole glass for free to grind into a mirror blank and when hardware shops would hand out teflon samples for free. Even finding the correct cardboard "sonotubes" can be a little tricky these days, and you're likely to blow out the price of an Orion or Apertura procuring a mirror (or sourcing the glass and getting it silvered.)

I hope that doesn't deter the "makers" among you from building a Dobsonian for the experience of it all, but if you want to get from zero to observing as cheaply as possible these days, you're probably better off just buying a Dobsonian similar to the one the parent comment linked.

We may never actually know, but I have my doubts anything like that was ever fielded. You're talking about beam-expansion over thousands of km for a sat-to-sat weapon instead of the tens of km for the eventually de-funded ABL/YAL-1 (some two decades after the suggested Soviet space-based system.) You avoid the atmosphere in space but you can't avoid diffraction. Teller's original concepts for SDI space-based lasers proposed literal nuclear bombs to provide the necessary energy density at range; neither those, nor the other host of exotic 80s-era directed energy weapons concepts seem to have made it into operation.

That sort of workflow sounds a lot like what you would get from a notebook like Jupyter, albeit you would have explicit block of code ("cells") to be executed together.

It looks like Spyder now features Jupyter Notebook integration as well: https://github.com/spyder-ide/spyder-notebook

>But saying that astrophysics is meaningful because some internet surveys find it to be "the sexiest job in the world", that's quite shallow.

To the author's credit, I read that sentence the other way around: the internet deigns "Data Scientist" to be the "sexiest job," but he doesn't feel satisfaction that matches that reputation.

>The internet says I have ”the sexiest job of the 21st century”, but I think my previous job was more enjoyable to brag about at birthday parties.

I would call most of what was done in this presentation Photogrammetry

https://en.wikipedia.org/wiki/Photogrammetry

> expecting answers for questions that were asked and answered thousands of times before

I don't mean to seem ungrateful for the work that open source maintainers do every day, but I think this sort of complaint is usually a symptom of a problem with either the documentation or the interface being unclear. These pain points are usually an opportunity for improvement in the product. On the other hand, there are probably more such opportunities than there are available maintainers...

Yes, definitely. I'll edit the parent to reflect.

Superconductivity is phenomenologically different than "very low resistance." The excitement about high-temperature superconductors is not only that there will be less power dissipated through power lines, but they will enable new technologies in power generation, high-energy physics research, analog and digital circuitry, sensors, and communications.

Because if you attempt to influence the state of the entangled bits--say, to set a bit to up/down (dot/dash or zero/one) state to form your message--you will break the entanglement. You can measure the states of the unperturbed entangled bits, and therefore know about the states of their distant entangled partners, but the message will be random. You could also influence the states of the bits while you create the entangled pairs, but then you have to carry them far away from one another (at less than the speed of light), so you won't be able to communicate FTL; you would just have a pair of messages in a bottle, so to speak.

>Isn’t the state still a probabilistic one at that point though? As in it’s not until it’s observed later that both particles instantaneously collapse into a correlated state. But the precise outcome of the observation isn’t determined before they’re separated. This is correct.

While I would also not presume to know how different our understanding of the universe may look in hundreds (or thousands!) of years, I do draw some exception to the following comment:

>Quantum entanglement, for example, breaks many of our assumptions about the impossibility of FTL travel.

Quantum entanglement can produce correlated measurements between systems, even when the entangled systems are separated by large distances. In a sense, this can be used to measure the state of an entangled system at great displacement "faster" than it would take light to travel from that distant system to the observer. However, the state of the entangled systems is prepared before the systems are separated from one another (at much less than the speed of light.) Any attempt to change the state of one of the entangled systems (at a distance) breaks the entanglement. Entanglement cannot be used to communicate information from one point to another faster than the speed of light. It certainly doesn't allow FTL transfer of matter/energy.