blackholesRhot

This is only for Starship testing. The issue should go away very soon, after at most a few more Starship tests.

This is only for Starship testing and should go away as an issue after a few more Starship tests.

RIP Peter

Two of the three co-authors, Dan and Sho, come from high energy physics backgrounds. Dan went from pure high energy to the intersection of HEP and quantum information. Boris comes from a pure math background but he has spent a lot of time learning physics as well. People's trainings influence their work :)

FYI I'm a Spinlaunch invesetor.

Just watched this video. His argument for why Spinlaunch won't work is basically:

1) in the video of their first test chamber (12m diameter) there's some dirt and rust, therefore they don't know anything about vacuums

2) in their first ever test fire of a projectile leaving their 33m chamber, the projectile is wobbling, therefore they don't know anything

3) in a mock up video they made of a future launch system the headquarters is close to the launcher, which might explode if there's a misfire, therefore they don't know anything

4) the founder has an uninspiring resume when you look online

'Add these up and there's no chance they'll succeed. What they've done isn't as impressive as 50+ year old gunships.'

Give me a break. Their rate of progress is exceptional. They've already overcome so many challenges. These are weak arguments. Doesn't mean they'll be successful. But these arguments are weak. Some quick counter-arguments

1-) the 12m test chamber was a demo chamber. they were constantly spinning it up and letting people go inside. doing tours. stress testing new materials and arms. blowing stuff up. if anything the fact that it was so reliable even with the imperfections is a positive

2-) when someone is learning to throw a football there's tons of wobble. spinlaunch needs to figure out a perfect spiral. these videos were from their first couple attempts ever out of a chamber. what they're showing is very hard. this team has shown an ability to innovate and improve. those were images of their first few attempts to "throw the football"

3-) give the team some credit. these videos are designed for the general public. what they built already has an incredible amount of kinetic energy. they stress tested many tethers (past their limits) before going to this scale. when you're picking on things as small as "they're going to kill themselves by sitting right next to the system" you clearly don't have much left to nitpick

4-) jonathan is an absolute genius. just because he has a spartan online bio and unorthodox background doesn't mean he's not an absolute force of nature. thunderf00t is a very smart dude. but i'd bet anything that in a debate -- on basically any topic -- jonathan would absolutely decimate thunderf00t

cheers to the builders

I was lucky enough to participate in one of these "educational programs". When I was in 6th grade I was selected to learn HAM radio and ask a question to the astronauts aboard STS-93. The program was called "Shuttle Amateur Radio Experiment" (SAREX). Long live SAREX!

"Yeah, got cut for brevity, but students definitely experience serious anxiety about even the five year horizon."

Lambda School is <5 years old. Pretty disingenuous man.

Completely agree.

Couldn't agree more.

the authors are basically rediscovering Chen-Stein’s concept of Poisson approximation... which can be used to almost trivially approximate any birthday problem variant. For example, how many people do you need to have a 50% Probability that at least 6 people were born on the same day on Jupiter? Ez w/ Poisson approximation. I first learned about this in Persi Diaconis’ graduate probability class but the method is very simple

https://projecteuclid.org/euclid.ss/1177012015

These concepts make more sense after one has been exposed to quantum mechanics. One of the first things you do in an intro to quantum mechanics class is calculate the energy levels of a Hydrogen atom (and then Helium.) Chemistry is literally applied quantum mechanics; and everything in quantum mechanics is probabilistic. A more accurate picture of an orbital is that it’s an energy level where a cloud of probability mass lives that corresponds to, if one were to take a photograph of the atom, the likelihood of finding an electron in any given location (wave function collapse.) But before a measurement, the electron really was a cloud of probability mass.

I respect Schneier but this is basically 10x-ing the word count on Terry Tao’s 2016 blog post:

https://www.google.com/amp/s/terrytao.wordpress.com/2016/06/...

Unacceptable to me that it wasn’t referenced as it certainly made the rounds in security circles.

Google Cloud and Microsoft Azure tutorials default to insecure datastore configurations; AWS, Rackspace and SoftLayer are better

One favorable interpretation is that he’s trying to say something similar to what Richard Muller said here

https://www.quora.com/What-is-your-opinion-on-the-UC-Berkele...

In the 60s and 70s UC Berkeley used to let controversial speakers present. The audience would listen patiently. And then take turns asking questions trying to catch the racist / bigot / Nazi / homophobe / whatever in the midst of logical failures. Now we just protest and shut down ideas via claims of political correctness. It’s not nearly as effective.

Also, this hedge became an extremely famous trade in the years to come, netting Mexico $8B in savings.

https://www.ft.com/content/ccd87f9e-9bd9-11de-b214-00144feab...

https://www.bloomberg.com/news/features/2017-04-04/uncoverin...

I was working in the crude oil / nat gas options pit at the NYMEX during the summer of 2008 when these trades went down (where much of Mexico's hedge was traded but not necessarily the author's portion.) A highly ironic part of this story is that the traders in the pit selling to Mexico thought they were getting an incredible deal. Both because the price of crude was so high at the time but also because they were able to "fade" the market. When you're in a pit like this, there are only ~100 "seats". At the time this meant 100 people who had firms with enough cash to front ~$1.5M so that you could stand for 6.5 straight hours in a tiny space at the NYMEX and shout back and forth. Basically what happens is someone will yell out to the other 100 people "what's the market on DEC'9 crude?" The point is they aren't supposed to say whether they want to buy or sell. Other people will yell out the prices they'd be willing to buy or sell at and the quantity. Say someone is willing to sell 200k options at $100/option, and someone else likes that price, they can yell "sold, 50 DEC'9 crude at 100." meaning they just bought 50k options expiring in December 2009. For this particular trade, there were three brokers that were known for representing mexico's hedge in previous years. Traders were expecting them to come back around this time. When one of these brokers came into the pit and yelled out "what's the market on DEC '9 crude" traders guessed he was hedging for mexico and quoted a price a full dollar above where the market was at. A bunch of people piled on willing to sell at even higher prices. The brokers had no choice but to accept this higher price. I was just a 22 year-old DRW intern on loan from a Stanford PhD program and in my head I was thinking "what the hell is going on.. that's not the fair price. I need to be selling!" I didn't actually sell anything because I didn't have the confidence or authority (it was my first month). But a senior trader explained this to me on our walk back to 7 world trade center after.

There were a couple papers a year ago showing pretty convincingly that yes there is some entanglement between some of its qubits. But from what I've seen there's zero evidence that they've done anything that would be hard for a classical computer. All signs thus far point to snake oil, but with a genuinely great team. They'll probably do something interesting 5 years from now and then Geordie will point back at all the naysayers and say "see I told you so!!"

A few comments as someone who works on the periphery of this field:

1. I started my PhD doing quantum information. People in quantum information spend a lot of time thinking about properties of entanglement. Someone below mentioned "a lack of new ideas". There have been quite a few important ideas in AdS/CFT (as a subset of string theory) over the past decade. One of the most exciting is called the Ryu-Takayanagi conjecture and it relates the amount of entanglement in a subsystem to the area of a minimal surface bounding said subregion.

2. Again, as someone who started purely as a QI person, it's shocking how much of the MATH of string theory has entered my research.

3. In my opinion, it's true that string theory hasn't made much progress over the past 20 years or so towards elucidating its potential role as a theory of quantum gravity; but in parallel there are amazing connections being made between string theory and quantum information. Look at the work being done by the "It from Qubit" collaboration for a sampling. This latter point is ~equally related to the recent decoherence of string theory as a subdiscipline. It's more like it tunneled to a state closer to QI.

4. The Firewall paradox is fascinating and it was originated by a bunch of string theorists (Almheiri, Marolf, Polchinski and Sully.)

5. Supersymmetry is in a corner; which is bad for string theory. But string theory is proving to be a powerful lens through which to study quantum entanglement. One step back, one step forward?

Anyways, saying that "string theory is our savior" or anything like that is bad etiquette. But the community is doing interesting things today.

And a journalists' views on string theory :-/

"Just because Witten is a genius does not mean he is infallible. He is wrong, I believe, that string theory will eventually be validated,..."

I find this argument inadequate. The conclusion may be true (that most venture funds lose money) but this article does a poor job of elucidating why this may be the case. There are many directions we can approach this from.

First, to simplify, instead of talking about an A and B and having 25% ownership after these rounds. Let's assume $10M is invested in the A for 25% ownership ($10M on a $30M pre-money valuation / $40M post-money.) Of course if each of these companies exits at exactly $50M and money just sits there for 10 years then the returns will be garbage. But in reality if you're investing at a post-money of $40M, very few of your companies will exit at $50M.

What actually matters here is what happens with money after exits. If money is returned to investors immediately, then what we want is to solve:

$100M * (1.12)^Y <= .25 * (exit price)

For example, if ONE company goes from $40M post and exits at $562M after 3 years, and then this money is distributed back to investors, then investors receive .25*$562 = $140.5M as a return, which is more than 12% per year for these three years ON THEIR ENTIRE $100M investment. (This assumed no subsequent dilution but you get the idea.)

If money isn't returned directly to investors then it needs to be re-invested. The point is, of course your venture returns will be poor if you just place your cash under a mattress post exits. The math becomes much more favorable for the VCs with realistic time assumptions.

This general area is called "concentration of measure" in case you want to Google around and find other examples. A simple but informative calculation is to compute the volume of a unit n-sphere and the volume contained between radius .9-1, and then see how the ratio of these scales with dimension. You'll see that that almost all of the volume is contained close to the boundary (exponential in dimension.)

I just responded on the Medium link but here's another short Kazakhstan bribe story:

I once took the train from Urumqi to Almaty. After touring around Kazakhstan for a week or so I went to the airport to fly to Baku. When I walked into the airport two police officers told me to follow them. They took me to a small room. They kept asking me “would you like any tea?” And I kept responding “no thanks, I really need to catch my flight.” They asked at least five times and then started using variants like “would you like coffee?” I ignorantly kept replying, “I’m really sorry. I appreciate the offer but I need to catch my flight.” After ten minutes or so they got frustrated and told me that I’m a stupid American and to leave and catch my flight. It clicked after sharing the story w/ some Kazakh folks that they were asking for a bribe. Sometimes ignorance is bliss. Oops.

It's a good idea but it has proven very difficult to implement in practice. The benefit of Escape Dynamics' (ours because I'm a Co-Founder) is that we keep the most complex parts of the system on the ground where servicing is cheap. Check out: https://en.wikipedia.org/wiki/SABRE_(rocket_engine)