petschge

30 ms·

301.
by petschge 7y ago
The are mainly large to increase resolution and sensitivity. Atmosphere limits how large you can make the mirror before hitting diminishing returns, but that is mitigated by good site selection, adaptive optics and lucky imaging (taking man
302.
by petschge 7y ago
Space based works for optical, but not all other wave length. For example it will also reduce the sensitivity of air cherenkov telescopes that detect gamma rays and that can not be moved to space.
303.
by petschge 7y ago
Tl;dr: Perfect subtraction is impossible due to physics. Problem is: With photon count the uncertainty in the number of photons also goes up (the relative error goes down). So even if you know that you should have received 100 photons from
304.
by petschge 7y ago
That depends on the wave length regime. Radio is firmly ground based, because you need huge dishes and potentially many (thousands) of them, at very precisely known distances. IR is mostly space based (with SOFIA and ALMA the notable except
305.
by petschge 7y ago
Mounting new detectors, fixing broken things, swapping out (optical) filters and shear mirror size are all a big problem for satellites. No atmosphere is nice for IR, but current optical telescopes are 10 meters and up, much larger than eve
306.
by petschge 7y ago
Depending on source class and telescope location it ruins between 1/3 and 1/2 of the available observing time. Are you willing to pay $1 more in taxes to to fund the extra telescopes we need to make up the short fall? Please write
307.
by petschge 7y ago
The main downside is that you need a place to store the water at the top. Favorable geography is most likely already in use. And building new lakes on hill tops alters the ecosystem quite a bit.
308.
by petschge 7y ago
The thing is: By the time the car has traction again it might have rotated around the up-axis. Getting back from that configuration do a less unstable configuration can very well improve if the car knows how to drift, especially how to go i
309.
by petschge 7y ago
All credit and debit cards that I have seen and used in South Africa do that.
310.
by petschge 7y ago
The article in Quanta magazine has also been discussed on HN: https://news.ycombinator.com/item?id=21743847
311.
by petschge 7y ago
About 5.7 percent. So not all that much. For comparison, binary is about 42 percent more efficient then decimal. See [1] for more numbers. 1: https://en.wikipedia.org/wiki/Radix_economy#Comparing_differ...
312.
by petschge 7y ago
And Cray will happily sell you an XC50 with Arm cores inside if you want that.
313.
by petschge 7y ago
As always there is a relevant xkcd: https://xkcd.com/386/
314.
by petschge 7y ago
Person doing simulations in plasma physics / astro physics here. I google tons of stuff every day. And I have a hard copy of https://www.nrl.navy.mil/ppd/content/nrl-plasma-formulary on my desk. And the PDF o
315.
by petschge 7y ago
and why can't we write it like you just did, with outer to inner dimensions going from left to right, i.e. in the same order the indices go when we actually use elements?
316.
by petschge 7y ago
8 pages of punctuation. So clear and easy to read.
317.
by petschge 7y ago
! might be "less" punctuation than [[ noreturn ]] but is a lot harder to google. And why do you need the "->"? That is just more line noise.
318.
by petschge 7y ago
I don't mind the const vs static. I mind just about everything else.
319.
by petschge 7y ago
I am sure there is good theoretical arguments. But they are hard on the humans. Ideally I would want something like constdata keymaps[1,2,3, u16] That is easy to read, gets rid of all the extra line noise and directly tells me everyt
320.
by petschge 7y ago
First example scrolling through that post: How is static keymaps: [[[u16; 3]; 2]; 1] an improvement over const uint16_t keymaps[][2][3] u16 is marginally nicer than uint16_t, but why is there a colon? and why do we have to ne
321.
by petschge 7y ago
The sizes for timber come the actual physical size early in the production process as your link nicely explains. Where to the "commonly known as" sizes for pipes come from?
322.
by petschge 7y ago
This issue apparently affected Windows 8.1, Windows 10 and their corresponding Server editions (32-bit and 64-bit) and has been patched since October 8th.
323.
by petschge 7y ago
The newer versions finally support a HTML5 console instead of the old java webstart horror they used to ship with.
324.
by petschge 7y ago
No training standards, not larger-scale oversight, a lot of "we have always done it like this here", a lot of "I know the DA and the judge because we go to the same BBQs", incentives to contribute to the (very local and
325.
by petschge 7y ago
When going to training classes on optimal I/O strategies for new supercomputers there is usually a bunch of people working for oil companies. The simulations I do for plasma physics are considered "easy" there because they ne
326.
by petschge 7y ago
As a physicist: where can you spot the physicist accent?
327.
by petschge 7y ago
This increasing spread of FAANG companies across all domains in an attempt to keep customers completely contained in their ecosystem reminds me of the megacorps in the Shadowrun universe. We are not too far away from the point where nationa
328.
by petschge 7y ago
It might very well be coincidental, because the hot compound also has anti-fungal properties. So the primary evolutionary benefit might have been that, not selection of animals eating the seeds.
329.
by petschge 7y ago
The energy content in a fusion reactor (even at the 3 GW output scale) is only a few mega joules, or in other words a few sticks of dynamite. Enough to damage the wall. Maybe enough to break the vacuum vessel. At that point the air would st
330.
by petschge 7y ago
Just skipping the staircase it not enough. To make the plane taller it needs a new landing gear. But that doesn't fit into the existing gear wells. So now you need to redesign the gear wells. But the gear nearly touch in the middle alr

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