lutorm

Joined 18 years ago

Karma
8,456
Submissions
3,443
Member since
Feb 25
Ex-astrophysicist, ex-rocket engineer, now working on a private project.
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Recent submissions

Comment · 1 year ago
So, as I understand it, the wing is broken down in sections, each of which will use some tabulated lift and drag for that airfoil at the current velocity vector and dynamic pressure? That seems fine. But it doesn't talk about how it deals with the fuselage and how it calculates its lift/drag. Calculating pressure drag is complicated and depends on the details of the airflow around the fuselage, and there's intersection drag at the interfaces with the wings/empennage. A significant portion of the drag for piston airplanes is also the cooling drag of the air that's forced through the cowling and the engine baffles. Does anyone know to what extent this is taken into account?
Comment · 1 year ago
I'm not understanding the situation. When I had RSUs as an employee, those grants were voided at separation. I only got to keep the RSUs that had vested before separation (which were then just common stock and that I had paid taxes on at vesting.)

Are you saying your former employer let you keep your unvested RSUs which subsequently vested at the IPO? (I've never heard of anyone getting to keep their unvested grants after separation.) Or were you still an employee during the IPO and left the company between then and now?

Comment · 1 year ago
Did European hard drives run at 3000 rpm then?
Comment · 1 year ago
I find it most annoying when moving your eyes. Anyone will notice the flicker if their eyes aren't stationary since then each "flick" will end up on a different part of the retina. So, instead of a normal motion blur you see a dashed line which is hard to ignore.
Comment · 1 year ago
The US supreme court has not, at least so far, endowed computers with personhood...
Comment · 1 year ago
... simply reprogramming the computer ...

So who makes the decision to do that?

I think most people are missing the point about accountability and thinks, in typical American fashion, about punishment. Accountability is about being responsible for outcomes. That may mean legally responsible, but I think far more important is the knowledge that "the buck stops with me", someone who is entrusted with a task and knows that it is their job to accomplish that task. Said person may decide to use a computer to accomplish it, but the computer is not responsible for the correct outcome.

Comment · 1 year ago
Comment · 1 year ago
I really don't care for controlling lights or whatever, but I find it very nice as a common place to monitor all the different things we have in the home: heat pump, evse, humidity in rooms, power consumption, state of lawn mower bot, etc.
Comment · 1 year ago
Even with a car's higher rolling resistance, most of the drag at cruising speed is aerodynamic, though.

But a commuter train, by definition, starts and stops a lot so it makes sense that a large fraction of the energy used would be for acceleration.

Comment · 1 year ago
Although "Top-level vdevs can only be removed if the primary pool storage does not contain a top-level raidz vdev, all top-level vdevs have the same sector size, and the keys for all encrypted datasets are loaded."
Comment · 1 year ago
Apart from just peace of mind from bitrot, I use it for the snapshotting capability which makes it super easy to do backups. You can snapshot and send the snapshots to other storage with e.g zfs-autobackup and it's trivial and you can't screw it up. If the snapshots exist on the other drive, you know you have a backup.
Comment · 1 year ago
Given their development pace, they really must succeed if they want their "slowly and carefully" model to be competitive.
Comment · 1 year ago
"Dark matter" is just a description that refers to matter which interacts gravitationally but not, or at least very weakly, in other ways. It doesn't imply anything about the nature of such matter. We know that there are several types of dark matter, specifically neutrinos and brown dwarfs, although it is now established that they don't make up anything near the density required by the cosmological models. Primordial black holes, which may exist, would be a dark matter. Some particle physics models, like supersymmetry, also naturally predict that there will be a massive particle that would behave like dark matter. So I don't think the analogy with the aether is very good, because that really was pulled out of thin air (pun intended). Given how successful general relativity is, it's perfectly rational to interpret the observations as probing mass distributions while assuming GR will continue to hold. There are of course people also assuming that GR is wrong and attempting to explain the observations without dark matter, but my impression is that they struggle to come up with self-consistent theories that fit all the data, although I'm not very familiar with that work.

What other people have been doing over the past 40 years is attempting to devise tests for these various dark matter candidates. We know, for example, through lensing observations, that MACHOs/brown dwarfs don't exist in the required numbers and that the neutrino mass seems too low. The problem, of course, is that there are only so many ways to try to observe matter that is truly dark.

I agree, though, that, in the end, it may be that dark matter will be an untestable hypothesis, just like quantum gravity or whatever.

Comment · 1 year ago
Well, it's not like people pulled it out of thin air. Both inflation and the lambda-CDM models are solutions to the GR equations, so in that sense it's perfectly justifiable to see if general relativity can explain the data. I don't think it's fair to say that it "makes no logical sense".
Comment · 1 year ago
But it seems that the principal objection to these counts is that birds don't necessarily die on impact but may travel quite far before succumbing to their injuries, so the counts necessarily result in an underestimate of the true effect. Are you saying the area that's surveyed is large enough that this isn't true?

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