maccam94

SpaceX's next-gen rocket, Starship, will have a 9 meter fairing and aims to be able to launch 100 tons into orbit for ~$10-100/kg. They also plan to support 3 launches per day. LSST has a primary mirror that's 8.4 meters wide, so something like it could potentially fit. Enormous radio telescopes can be constructed from a large array of smaller satellites via radio interferometry.

> BTRFS was developed largely concurrent with, and in direct competition to Sun's ZFS

ZFS started development in 2001, and released on Solaris 10 in 2006. Btrfs started development in 2007, and the disk format was stabilized in 2013. ZFS has continued to gain features over the years, but I would say btrfs was largely developed after ZFS and still hasn't reached feature parity with the original release of ZFS due to the RAID5 issue.

The recipe for Roman concrete was recorded, but most places didn't have access to the materials and conditions necessary to produce it: https://www.sciencemag.org/news/2017/07/why-modern-mortar-cr...

I thought the main reasons were cost and maintainability? Both of which should be improved with the ability to launch larger, heavier, and more numerous payloads.

Initial versions of Starlink would reflect so much light that they would overwhelm significant areas of the sensors. If the reflection issue is resolved with the new sun shades, then the satellite trails can be removed during post-processing.

Nuclear thermal rockets are much more interesting IMO because they were actually viable and in development until Nixon killed them for no good reason. They're coming back now though.

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

https://spacenews.com/momentum-grows-for-nuclear-thermal-pro... (2019)

Cambridge Fusion Systems[1] is a private company spun out of MIT that is building a proof-of-concept reactor based on these new magnets within the next 5 years.

Breakthrough in Nuclear Fusion? - Prof. Dennis Whyte (2016) - https://www.youtube.com/watch?v=KkpqA8yG9T4

Timeline (in case you want to skip over some parts):

  00:01:00 - introducing Dennis Whyte, MIT department head for nuclear science
  00:04:24 - presentation starts
  00:06:00 - identifies breakthrough with REBCO magnets
  00:07:25 - explains deuterium-tritium fusion
  00:12:30 - basic metrics for reactor performance
  00:17:15 - energy output of other previous fusion experiments
  00:19:00 - examines ITER and the problems of its approach
  00:22:00 - problems solved by high energy magnetic fields
  00:28:15 - full scale reactor concept, teardown of REBCO magnets
  00:37:00 - design limits and margins
  00:39:00 - fixes plasma instabilities found in weaker magnetic chambers
  00:40:00 - maintainability, lifespan, component replacement
  00:45:00 - solution to neutron damage and energy capture
  00:50:30 - cost and profitability
  00:54:00 - full graph of field strength vs reactor scale (and thus funding requirements)
  01:01:50 - Q&A
  01:30:00 - question about the biggest risks

He gave another talk in 2019 with more numbers and even more confidence: https://www.youtube.com/watch?v=rY6U4wB-oYM

1: https://cfs.energy/technology

You don't need AI, just use stronger magnets[1]. ITER was conceived before high temperature superconducting magnets were discovered, so it has more trouble maintaining plasma stability.

1: https://www.youtube.com/watch?v=KkpqA8yG9T4&t=39m0s

MIT-affiliated company building a reactor using these magnets: https://cfs.energy/technology

IIRC, when ITER was conceived, it wasn't a waste of money. They just chose a conservative development path that was expensive but very likely achievable. Technology and theories have since advanced that might leapfrog it, but the project has still contributed a great deal to our understanding of fusion and the engineering required to produce it.

Relevant talk by one of the MIT professors working with Commonwealth Fusion Systems:

Breakthrough in Nuclear Fusion? - Prof. Dennis Whyte (2016) - https://www.youtube.com/watch?v=KkpqA8yG9T4

Timeline (in case you want to skip over some parts):

  00:01:00 - introducing Dennis Whyte, MIT department head for nuclear science
  00:04:24 - presentation starts
  00:06:00 - identifies breakthrough with REBCO magnets
  00:07:25 - explains deuterium-tritium fusion
  00:12:30 - basic metrics for reactor performance
  00:17:15 - energy output of other previous fusion experiments
  00:19:00 - examines ITER and the problems of its approach
  00:22:00 - problems solved by high energy magnetic fields
  00:28:15 - full scale reactor concept, teardown of REBCO magnets
  00:37:00 - design limits and margins
  00:39:00 - fixes plasma instabilities found in weaker magnetic chambers
  00:40:00 - maintainability, lifespan, component replacement
  00:45:00 - solution to neutron damage and energy capture
  00:50:30 - cost and profitability
  00:54:00 - full graph of field strength vs reactor scale (and thus funding requirements)
  01:01:50 - Q&A
  01:30:00 - question about the biggest risks

A more recent (2019) talk with more numbers and even more confidence: https://www.youtube.com/watch?v=rY6U4wB-oYM

I believe for performance and error correction features for spinning hard drives. Check out the tables and graphic in the overview section here[1]. Any write to a sector requires updating the checksum, which means the whole sector has to be read before the drive can complete the write. Since the sector is probably in the kernel disk cache already, the whole sector can be flushed to disk at once and the drive can compute the checksum on the fly (instead of flushing 1 byte, making the drive do a read of the sector, recompute the checksum, and then do a write).

1: https://en.wikipedia.org/wiki/Advanced_Format

I believe they meant that audio captchas have become inaccessible to humans in general. Bots have gotten so good at audio captchas that the difficulty level has to be high enough that humans are also unable to complete them.

But technically you could try a dictionary-based brute-force attack on a user with a weak password and crack it regardless of the hashing scheme.

Encrypted implies that the passwords could possibly be decrypted with a key.

Couldn't a blood clot cause swelling or increase pressure around an un-ruptured aneurysm, causing it to rupture?

There are still testing backlogs for COVID, it can take multiple days to get results (assuming the doctors decide to run the test). Link #2 also says: It’s hard to know for sure [if clotting is a major factor], because the clotting problem is apt to go undetected.

Since most people think of COVID as a respiratory disease and the clotting symptoms aren't as well publicized, doctors may not always call for the test when respiratory symptoms aren't present.

I've seen multiple reports of severe blood clotting and strokes in COVID patients, including those who are otherwise asymptomatic, including people under 50.[1] Given that there is a pandemic going around with similar symptoms, I don't think this is a huge leap (but again, I am not saying it's anywhere near certain either). I probably should have used this source in my original comment, I just grabbed the first link I had handy.

[1]: https://www.biospace.com/article/covid-19-increases-risk-of-...

[2]: https://news.weill.cornell.edu/news/2020/07/what-is-known-ab...

[3]: https://directorsblog.nih.gov/2020/06/11/searching-for-ways-...

I would not be surprised if he is diagnosed with COVID-19, it can cause blood clots that obstruct blood flow.

"Severe brain haemorrhage and concomitant COVID-19 Infection: A neurovascular complication of COVID-19": https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7199686/

I would not be surprised if he is diagnosed with COVID-19, it can cause blood clots that obstruct blood flow.

"Severe brain haemorrhage and concomitant COVID-19 Infection: A neurovascular complication of COVID-19": https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7199686/

I am assuming that it would work with clang-compiled[1] kernels only at first.

1: https://www.kernel.org/doc/html/latest/kbuild/llvm.html

Some of the wind sensitivity comes from the hulls being long and narrow. SpaceX's Starship design will be much wider and thus more robust compared to their Falcon 9 rocket.

The Boom plans to land at 185 knots/213MPH, comparable to a 737-800. They probably need a fraction of the distance to stop though, since the plane has about 1/3 of the seating capacity.

It is fundamentally impossible to have secret ballots[1] in a digital system along with provable integrity. Secret ballots are necessary to prevent vote buying, intimidation, and coercion. If no one can prove which voter submitted which ballot, nor what choices a voter indicated, the voter is free to choose without risk of repercussions. The breakdown of any digital voting system is always with verification.

With paper, the voter can see that their ballot is securely stored under the supervision of the election operators, and they can see that representatives from multiple parties watch the movement and counting of the ballots.

In contrast, with a digital system it is impossible to verify that your ballot was delivered with the choices you intended without also being able to show that proof to anyone else. It is important that the voter is unable to show proof of their vote for the reasons mentioned above. Unlike a paper-based process, you cannot directly observe the functioning of an electronic circuit, the transmission of data over cables, or the storage of bytes in memory, and neither can anyone else trying to verify the integrity of the process. You'll never know if someone has replaced any of the hardware or software components with malicious versions designed to fool voters and rig elections.

1: https://en.wikipedia.org/wiki/Secret_ballot

Given the .moe TLD, I think it is a reference.

There are multiple shipping corridors through areas with less than stable/friendly governments. Sure, there are the pirates off of Somalia, but there's also governments that could threaten blockades or charge steep fares to pass by. Check out this map and consider how many ships are passing by China, the Middle East, and Africa.

https://www.wired.com/2010/01/global-shipping-map/

The carrier fleet is more about maintaining the two-front fight capability. It sounds like the military is shifting away from that strategy however:

https://www.bloomberg.com/opinion/articles/2019-06-11/two-wa...

Running multiple containers is faster and more efficient than multiple VMs. Running a container on the same kernel as the host is faster and more efficient than a VM. If you're trying to run an app across different OS kernels, you still have to use a VM unless you can compile your app on that kernel natively. This project really doesn't do much beyond what a VM gets you, and you still have to configure the host outside the container to enable virtualization.

Upmass is way more important right now than downmass. If you want more inspiration, know that SpaceX is making a significant profit on these flights despite their price being a small fraction of shuttle flights. And they're pouring it into their next generation rocket, Starship, which they plan to launch around the Moon in a few years.

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

Scooters yes, e-bikes no. The e-bikes have much bigger batteries. More energy = bigger boom. They also probably only had a fraction of chargers compared to the number of bikes, and sourcing more would probably take a lot of extra time and expense. It would have been better if they could find another bikeshare operator to sell to, but I can understand why they didn't sell to consumers.

Oh interesting, TIL. The syntax looked similar and it's a Google project, so I assumed gn was just some BUILD file generator on top.

Chromium uses a build tool called bazel. //base is a bazel path, where // is the root of a workspace (which is usually a version controlled repository). Thus it is referring to https://chromium.googlesource.com/chromium/src/+/refs/heads/...

1. Starship - https://www.spacex.com/vehicles/starship/

Completely reusable rocket that can carry 100 tons into low Earth orbit, refuel, and then continue on to places like Mars. Launches are estimated to cost SpaceX about $2M, compared to the SLS $1B (estimated, similar lift capability) and space shuttle $1B (27 tons). The engines are real, test vehicles are flying (another test launch is likely to happen in the next week or two). Follow the SpaceX subreddit for progress updates

2. Commonwealth Fusion Systems - http://cfs.energy

Lots of reactors have struggled with scale and plasma instability. CFS has adopted a design using new REBCO high temperature superconductor magnets that are stronger and smaller, which can be used to build smaller reactors and better stabilize the plasma. They are building a prototype called SPARC, expected to produce net energy gain by 2025.