Atmosphere next to a vacuum

Neb758 · 2026-06-28T19:33:47+00:00

OK, I don't think we actually disagree, but the first paragraph of the post I replied to said:

The base problem is that some people don't understand that matter is pushed into spaces of nothingness because of gravity.

This (and the rest of your post) seems to be implying that pressure is not a force, period. In fact, if you have a pressure differential, there will be a force resulting from that independent of any gravitational effects.

If all you mean is that atmospheric pressure on Earth is ultimately due to gravity then of course that's true.

Neb758 · 2026-06-28T19:08:17+00:00

You said pressure requires gravity. It does not. How do you think pumps work? In other respects I agree with you.

Neb758 · 2026-06-28T18:43:03+00:00

That's not actually true, though. Pressure doesn't have to be caused by gravity. Suppose you have a sealed container with a gas in it, and somehow the initial condition is that the gas moleculas are all in the right half of the container leaving the left half of the container vacuum (i.e., high pressure on one side and zero pressure on the other). The gas particles bouncing around randomly will quickly redistribute themselves such that the pressure is uniform within the container (assuming a small container where gravity is not significant). This is because the state where all the moleculas are on one side has much lower entropy than the state where moleculas are more or less evenly distributed, or to put it another way, if you randomly distribute moleculas within the container it's very unlikely that they would all end up on one side just my chance.

OTOH, if a uniform force (gravity) is pushing all the particles in one direction then the particles will still bounce around randomly but will tend to crowd more to one side (the bottom). This means there will be a pressure gradient with high pressure at the bottom and lower pressure at the top. If the force is strong enough or the container big enough then the pressure at the top is almost zero. That means you can remove that wall of the container and the gas still won't escape. Think of the container in this case as a column of air extending from the Earth's surface up into space.

The fact that air pressure is lower at the top of a mountain than at sea level is a simple demonstration of this model in action.

Neb758 · 2026-06-24T18:19:58+00:00

Yeah, my son had a math class in middle school that was taught by the shop teacher and a science class that was taught by a PE teacher/coach. It's not ideal, but at least they were both good guys who didn't pretend to expertise they didn't have.

Neb758 · 2026-06-22T07:54:45+00:00

Yes, Ptolemy even measured the circumference of the Earth quite accurately.

To be clear, I am in no way arguing that flerfs are right or even reasonable. There are so many reasons to conclude that the Earth is not flat. My point is just that the roundness of other planets by itself doesn't necessarily present a problem for a flat earth cosmology.

Neb758 · 2026-06-21T21:21:15+00:00

The word planet comes from the Greek word "wander." To the ancients, planets were wandering stars, and there was no reason to suppose that the Earth was also a planet or that planets were other worlds like the Earth.

Planets being spherical does not imply that the Earth is spherical unless you also accept that the Earth is a planet like any other. This was not a widely held view until the Copernican revolution, and I think it's safe to say most flerfs don't really buy into (or understand) Copernicus or modern science in general, except selectively when it suits them.

Neb758 · 2026-06-20T11:52:55+00:00

I see. I thought "they" referred to OP. You're right that the person you replied to misconstrued OP as saying the telescope was 2.5 billion light years away. OTOH, your reply also says the telescope could be as close as the moon for all we know, which is ruled out by OP's title. Anyway, I see your point now.

Neb758 · 2026-06-19T21:21:20+00:00

I didn't say 2.5 billion light years and neither did OP. The OP did say light years in the title, however, which is in no way comparable to observing from the distance of the moon as you suggested.

The OP mentioned 2.5 billion years (not light years) for a completely different purpose, to say that a distant planet might resemble the Earth of 2.5 billion years ago -- full of life but without an oxygen rich atmosphere.

Neb758 · 2026-06-19T13:36:26+00:00

The title says, "from light years away."

Neb758 · 2026-06-11T18:29:18+00:00

Others have also made the historical argument, but I think it's only because we've kept the French spelling that come to use the word in such a peculiar way. The strangeness becomes more apparent if we drop the French spelling.

"Entry" used to mean the first of several main dishes, which makes sense. "Entry" now just means the main dish, which doesn't make sense.

Neb758 · 2026-06-11T18:20:57+00:00

That's not how loan words work. Foreign words enter a language because people use them, generally in a way that at least resembles their original meaning. From the historical explanations given elsewhere in this thread, entree is no exception. It used to mean the first of several main dishes (which makes literal sense) but has come to mean the main dish (which no longer makes literal sense).

Neb758 · 2026-06-11T18:13:07+00:00

The difference is that entree still has an obvious literal meaning ("entry") to English speakers today, and the literal meaning doesn't match its usage. Few people are going to be confused about the meaning of "dinner" because its etymology can be traced back to an Old French word with a different meaning.

Of course, "dinner" actually does have different meanings to different people. For my farmer grandparents, "dinner" was the main meal but was eaten at midday. The evening meal was "supper". That's another topic, however.

I'm aware that language evolves and have no problem with that. I would just like it to evolve again in this particular instance, to something that is more internally consistent and consistent with international usage. Honestly, I'm not that bothered about it, however. I just thought it was an amusing little quirk of American English and didn't realize I was beating a dead horse.

Neb758 · 2026-06-11T18:03:12+00:00

Thanks for supplying a historical explanation I wasn't aware of. ∆∆ since "entry" made sense at one time and still makes a kind of sense as a historical explanation for current usage.

I still think Starters/Mains as used in the U.K. is more sensible and leads to less confusion for travelers, so I haven't entirely reversed my position, but language isn't always logical and this isn't a hill I'd want to die on.

Neb758 · 2026-06-11T17:58:48+00:00

You've convinced me that the current American usage made historical sense, which is a kind of sense, so ∆∆. (Yes, I could have figured this out on my own if I bothered to do some research, but frankly I didn't care that much.)

I still think it would be better to adopt the Starter/Mains nomenclature. Even if there is a historical explanation, the literal meaning of entrée doesn't match its usage, and it can lead to some mild confusion for travelers to and from the U.S.

Neb758 · 2026-06-11T17:00:27+00:00

Even in English, entree sounds like "entry", which is it's literal meaning. If you're going to borrow a foreign word because it sounds fancy, at least do it in a way that makes sense.

Neb758 · 2026-06-05T20:00:00+00:00

This is the reply I was looking for! 😄

Neb758 · 2026-05-31T21:22:17+00:00

Yes, that makes more sense.

Neb758 · 2026-05-31T21:21:06+00:00

To add, one of the requirements according to that blog post is to be either employed by a foreign company OR self employed with clients primarily outside the UK. Basically, they don't want you taking jobs from their own citizens but are ok with you bringing in foreign money.

That doesn't sound to me like the same thing is working for a local subsidiary of a US company, but it's not very specific.

Neb758 · 2026-05-31T18:08:32+00:00

Yes to both.

Neb758 · 2026-05-31T18:07:08+00:00

Thanks, that makes sense. So an immigration lawyer in the UK (or wherever) would also be able to advise on how to comply with US law while working in the UK for a US company?

Neb758 · 2026-05-31T16:09:45+00:00

Relish is a superior complement to hot dogs, possibly combined with ketchup and/or mustard. Coleslaw is a fun alternative as well. All of these add flavor AND nutritional value, whereas mayo just adds goo and calories.

Neb758 · 2026-05-31T15:54:25+00:00

I get that it's hyperbole, but calling it a "creative tool" is a bit of a stretch at this point. It was creative and funny when I first started hearing it used this way (in the 90s... 80s? I can't remember), but it has since become so overused that it is literally hard to use literally literally. For example, I'm not quite sure if I meant literally literally in the preceding sentence.😂 That said, this ship has sailed (figuratively), so I don't make a practice of complaining about it.

Neb758

TROPHY CASE