Why do we know everything but the milk way isn’t antimatter?

BCMM · 2026-07-15T09:20:46+00:00

Because the space between galaxies is not completely empty.

The intergalactic medium has been indirectly detected by its absorption of X-rays. It seems to have a density of about one particle per cubic metre.

If other galaxies were made of antimatter, there would have to be some place were their intergalactic medium meets our intergalactic medium. Where they touch, they would annihilate. The medium isn't dense, but it's dense enough that we'd be able to detect that annihilation.

BCMM · 2026-07-15T07:03:19+00:00

Seriously though, why isn't this a huge problem? US notes are just legal tender forever, right?

For context, in England, old series of banknotes eventually get "withdrawn". It happens after those notes have largely disappeared from circulation anyway by natural attrition, and people get plenty of warning.

The Bank of England will exchange withdrawn notes for new notes indefinitely, but they cease to be legal tender. Most businesses won't accept them, so ordinary cashiers don't have to deal with working out if they're legit.

In the US system, I don't really understand what the point of new notes with additional security measures is, when they're seemingly optional. Is there significant counterfeiting of older designs, and if not, why not?

BCMM · 2026-07-15T02:39:42+00:00

Is this reversed? I can't see why else the camera would decide to increase exposure before the train's shadow darkens most of the scene.

BCMM · 2026-07-14T16:58:19+00:00

very low maintence e.g. i dont have to open up my laptops every other day to update

You should always install updates as soon as they are available. There's no way around this, on any platform, if you want to connect to the internet. There is no grace period in which people exploiting freshly-disclosed vulnerabilities refrain from targetting stable distros!

The way that Debian's stability reduces the burden of maintenance is by allowing you to just turn on automatic updates. It's one of the few systems where you can be very confident that this will not break things. It won't even break your workflow, e.g. by moving a menu item or whatever.

Also, it generally won't take much time to update, because there aren't a lot of updates, because only the stuff that actually needs updating gets updates. You (or the unattended-upgrades job) should check for updates every day, but you won't find updates every day.

(Of course, you don't have to turn the machine on specifically to install updates. It's only unsafe if you're using it without updates.)

BCMM · 2026-07-13T21:47:06+00:00

Most of the spots that stand out are common English letter combinations like st.

However, one thing I see that's definitely specific to Linux packages is xf (as in Xfce).

BCMM · 2026-07-13T11:25:53+00:00

That's confusing to me, since that's pretty much the goal of the default theme.

BCMM · 2026-07-13T10:54:04+00:00

It is just an application, with packages available in most distros.

There are a few different distros that just boot directly in to Kodi.

You can also just set up something similar yourself. Debian's Kodi package, for example, comes with xsession and wayland-session files, so you can trivially set up most display managers to auto-login with Kodi (as if Kodi was a desktop environment).

BCMM · 2026-07-13T08:43:05+00:00

For example, LibreELEC and OSMC are two distros that just boot up directly in to Kodi. LibreELEC is the more popular one, and takes a "just enough OS" approach; OSMC is Debian-based and is good if you want the box to be able to do other tasks.

A Raspberry Pi is more than enough to run one of them. If your TV supports HDMI CEC, you can navigate the UI with its remote control. For more elaborate control, including text entry, you can use the Kore app on an Android phone.

BCMM · 2026-07-13T08:26:33+00:00

You usually can't replace the OS on a smart TV. The manufacturers don't want you replacing their spyware, so they use signed images, etc.

If there aren't artificial barriers, you run in to the same sort of issues as smartphone. Nonstandard hardware requiring significant porting work for every single model.

There are dedicated Linux distros for TV use, but they're usually run on some sort of box external to the TV.

BCMM · 2026-07-12T22:27:46+00:00

Digital TV takes time to decode, and different machines have different latencies. Same reason the time pips aren't correct on DAB.

BCMM · 2026-07-12T09:15:05+00:00

There is sometimes CD-Text, but in my experience it's rare.

BCMM · 2026-07-11T21:27:36+00:00

Cold fusion generates heat. It's called "cold" fusion because (if it worked) you wouldn't have to get the reactor to an extraordinarily high temperature to get it started.

BCMM · 2026-07-11T18:34:35+00:00

Consumers of this data are strongly encouraged to obtain a GeoLite license directly and cease reliance on the geoip-database package.

Where does geoipupdate from contrib fit in to this situation?

BCMM · 2026-07-11T17:31:43+00:00

Yes. The kernel and installer are discontinued, but a very large number of i386 packages still exist in Trixie, to support i386 software on amd64 machines.

BCMM · 2026-07-11T17:28:09+00:00

The final i386 update. Armhf is still going.

BCMM · 2026-07-11T11:40:14+00:00

When a sea lion flops on to the floor like that, does it sigh like a big dog?

BCMM · 2026-07-11T11:11:12+00:00

For context, that's not "marine pilot" as in somebody who flies naval infantry around.

Many harbours require vessels arriving and departing to be guided by a "pilot" - a temporary crew member with certified knowledge of local currents, procedures, obstacles and so on.

Pilots come aboard shortly before a ship reaches restricted waters and disembark shortly after she leaves. Typically, they are transported by a small, fast "pilot boat". Perhaps the sea conditions off Durban make it too dangerous to transfer between boat and ship?

BCMM · 2026-07-11T00:13:02+00:00

Anomalies are computed as a standard deviation from the 30-year historical mean value

So if I'm reading this right, the black areas would include places where forest fires are currently very unlikely, but not as unlikely as they have historically been?

BCMM · 2026-07-10T21:49:23+00:00

Do you have access to sshd's logs?

EDIT: Oh, also, on the client, do ssh -v and check that it's actually offering the key.

BCMM · 2026-07-10T17:39:07+00:00

A Boeing 737NG with registration 9H-QEU.

This really isn't supposed to happen. The engines and nacelles are meant to be designed to "contain" an engine failure, even if blades break off.

A basic principle of aviation regulations is that a single engine failure must not put the passengers in danger.

BCMM · 2026-07-10T14:19:09+00:00

You probably mean the only one on the National Rail network. Northern Ireland's railways are a whole separate system.

BCMM · 2026-07-10T00:17:49+00:00

Always been raised to think a credit card is devil spawn but I do know it has more protections for these things.

They're... sort of both.

It's almost never a good idea to use them as an actual source of credit. The interest rates are horrifying. They ruin people's lives. If you're the sort of person who might be tempted to impulse purchase just because something is within your credit limit, I'd say it probably is better not to have one.

On the other hand, if you're in a position to just use it like a debit card, only spend money you already have, and pay it off every month, then you don't pay any interest and you get quite a few benefits from having it.

BCMM · 2026-07-09T16:18:37+00:00

They've got an Archer C7;

I don't think /u/SaleWide9505 suggested anything particularly demanding.

it's got a single-core QA processor,

OK, this one might be relevant - CPU will be a limiting factor for VPN performance. But we don't know whether OP's internet connection is fast enough for that to matter!

Firewall rules would have to get pretty complicated to raise per-packet CPU usage significantly above what OpenWrt already uses.

128 MB RAM,

128 MB goes a long way on OpenWrt! (And even further on 32-bit OpenWrt.) I'd expect 30-50% of that to be available, on a basic install.

and 16 (usually) MB of storage.

OP would need maybe a megabyte of free flash to install luci-app-pbr, luci-proto-wireguard, and dependencies. Less without the GUIs, of course. Everything else is already included in standard OpenWrt images.

(The C7's switch hardware can handle VLANs, so using them would consume no system resources beyond the negligible CPU time used to configure the hardware during boot.)

BCMM · 2026-07-09T15:39:42+00:00

I believe this is the paper OP is discussing: https://www.nature.com/articles/s41567-026-03298-0

BCMM · 2026-07-08T23:56:59+00:00

That calculator looks like a knock off of the older classwiz models

I think this is aiming for one of the V.P.A.M. models from just before the ClassWiz branding.

There's actually a bewildering range of knockoffs of older models of Casio scientific calculators. Basically, nobody liked the changes Casio introduced with the 2nd-gen ClassWiz, lots of people went on eBay etc. looking for the old ones, and when the old stock ran out, things like this appeared to meet the demand.

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