This feels like a completely post-hoc explanation. If you have a real source, I would love to read it.

Seems much more likely its called an inverter because it performs the inverse operation of an already established device, the rectifier.

Yours? Your mom. The egg that was fertilized to make you was a cell.

Keep in mind, this is not necessarily what is consciously going through people's minds when they think about gender identity. Cis women certainly don't have to think "I am happy with the way society treats me" to identify as a woman. They don't even have to feel "comfortable" with the way they are treated as a woman. It's hard to separate the "experience of being a woman" from "being a woman" when we are the sum of our experiences.

But that is also relevant to what it means to be trans, because it's not just about identifying as something else, it's also about not identifying as something, too. And again having to navigate a world where most other people are using gender as a proxy for sex and sex as a way to determine part of how they treat you means that there are advantages to having an outward expression of gender that fits with the expectations of others.

Mostly it has to do with how other people treat you.

If we treated everyone as if their biological sex didn't determine anything about them other than who they are capable of reproducing with, the idea of "not feeling like the sex you were born with" would seem a lot stranger. Most of what people describe when talking about what it feels like to identify as an gender has to do with the expectations, prejudgement, and treatment from others.

It's really a way of navigating and managing other people's expectations for you in a world where many, many people still use sex as a way of categorizing people for things OTHER than procreation, and use gender presentation as a proxy for sex.

Your blood pH should be in a specific range. CO2 dissolved in your blood makes it more acidic. When you hyperventilate, the concentration of CO2 in your blood drops. When you breathe into a paper bag, you inhale more CO2 than you would just breathing air from outside the bag, and it helps compensate for the extra CO2 you're exhaling.

They make it so that each eye sees a different image. When you look without the glasses, you see both images with both eyes, instead of one image for each eye. The light intended for each eye has different polarity, and the glasses are polarized in different directions to block the light intended for the other eye.

Information is encoded by changing the signal that is being sent. The amount of data you can transfer per second is a function of how often you can change the signal being sent, and detect the change on the other end. We can do this really, really, fast.

Once you've reached the limit of your ability to make the signal change more often, you can increase the amount of information transferred by making each unit of this signal contain more information than just "on" or "off". Instead of a signal where everything above a certain amplitude is a 1, and below it is a 0, you can split the amplitude into more sections, each one encoding multiple binary digits. You might split it into four different amplitudes corresponding to 00, 01, 10, 11.

You can build more and more advanced ways of encoding more information into the signal. For example, you can also send multiple signals of the same wavelength that are out of phase with each other, and if you have two signals, and one encodes phase angle and the other amplitude, now you can combine those signals to create a "line" that points to a location in 2D space. Then you can construct a grid of possible combinations of bits, 0000, 0001, 0010, 0011, etc. in that 2D space that each unit of the signal "points" to.

On top of that, you can send multiple different data streams through the same fiber at the same time by using different wavelengths of light for each of them.

And then you have many, many fibers in the same cable.

Yes, there would be time dilation. How much depends on the distance the planet was orbiting. It wouldn't be close to the same amount of time dilation as Miller's planet unless you were somewhere between 1 and 2 meters from the event horizon, which isn't exactly a reasonable orbit for a planet.

Yeah, sorry, that's just not how it works. It's not misleading to call something that doesn't interact with electromagnetism, and thus light, "dark", and it's not misleading to call something that is acting like matter "matter". Whatever hangups you have about these words are really on you. It's not even close to misleading, and even when the short terms given to complex ideas are "misleading", it still doesn't make them manipulative. Things catch on, and once that happens, it isn't getting undone. That's not a conspiracy to manipulate you.

That's not manipulative. It's reality.

>Matter" means something objectively detectable made of physical particles which you're able to interact with.

No it doesn't. And you don't get to decide that it does. But it does tell you something about the way "dark matter" is expected to behave based on observation. So does the "energy" in dark energy. These words are meaningful within the context, although like with all things in physics, words will always fail to convey a concept based on math, because they're meant as labels for things you are already informed about, not as a way to convey understanding.

It's honestly amazing how often dark energy is brought up without mentioning that:

1. non-zero vacuum energy is a prediction of QFT

2. non-zero vacuum energy would contribute to the cosmological constant

Instead people just use the same line over and over about how it's completely mysterious and we have no idea what it is.

It's nice to see an article written by an actual astrophysicist for a popsci audience that mentions these things and actually clarifies some of the things that popsci "journalists" like to make sound as sensationalized as possible.

It sounds like you're imagining "expansion" to be some outward expansion from a point in space, rather than spacetime expanding everywhere. There's no reason to tie the age of the universe to its size (other than just how its size changes proportionally, relative to itself with time). It could have been any size prior to inflation. The fact that the observable universe is larger in lightyears than the age of the universe in years is not surprising or particularly meaningful.

Yeah, it's definitely not right in the details. Maybe I shouldn't have emphasized "ever" so much. But my goal was more to dispel much bigger misconceptions that went into the question rather than cover all the little details of how these horizons work.

I don't think there's really a good way to answer these complex questions that were formulated based on a lot of complete misunderstandings of what these words even mean. At least not while still sticking to just words. But saying "nothing will ever appear to be moving at C from our point of view" was probably a bad choice. But it would be true if the hubble sphere never changed in size.

The fact that we can see light from galaxies with recession velocities higher than C is one of those facts that is truly awesome to point out, but is pretty much guaranteed to just confuse someone who probably has only learned about cosmology through popular science.

Nothing will ever appear to be moving at the speed of light from our point of view, because if it's moving at C away from us information will never reach us.

The hubble horizon is the distance where something would be moving faster than C due to expansion right now. But that's 14+ billion lightyears away, so even if we could receive information from those galaxies to see them, it wouldn't arrive for many billions of years.

But it will never arrive if it was emitted after the object was already past the hubble horizon.

Personally, I think the best way to learn about what we know now is to learn about the history of our knowledge of astronomy and space. It's a lot easier to understand why certain things were significant and the train of thought that went into them with historical context.

Check out the book "The Watershed" by Arthur Koestler. The invention of the telescope was a true turning point for our understanding of the universe. Humans were fascinated (and confused) by the sky and the stars and planets for 10s of thousands of years, and then suddenly we could see things like moons orbiting Jupiter, mountains casting shadows on the moon, and crescent lighting on Venus. Everything became more real and tangible and open to scientific exploration, and really helped push people towards the idea that we are not the center of the universe.

Astronomy really was the spark for the scientific revolution.

In theory, an IQ test is supposed to measure your "potential for learning". The idea is to separate knowledge from the ability to learn something/problem solve, so that ignorance doesn't change the results. In reality this is can't be done perfectly and you can absolutely get better results on an IQ test by practicing. But this means that people who already have gained some of the same skills that would be honed by practicing for the IQ test will score better than someone who has not gained those skills.

So IQ tests are intended to measure something that you shouldn't be able to change, but fail to do so perfectly, and so it is NOT always the same. But the true value of the thing that IQ is a proxy for shouldn't be able to be changed.

Because the words I typed are not labels for the underlying math. Words that ARE just labels for complex underlying math are significantly different from words that aren't.

Are you really going to be this facetious?

Stop trying to understand physics through words instead of math. The words are meaningless without knowing the math that they are meant to describe. The words themselves are not understanding.

... yes? I hit 45mph literally every single fucking day on my bike going downhill.

> i see no reason to not believe that there are planets experiencing many years in the matter of a short time for us

Well, one good reason is "time dilation doesn't work like that". You can't have negative velocity or negative mass, so nowhere in the universe is significantly faster than on Earth.

Look, you're not doing a great job of saying what exactly is confusing you, so I'm not sure where to start.

The earth spins. That means that all the things in the sky are always moving. The sun sets because the Earth spins. Stars also rise and set just like the sun. The angle they trace through the sky varies depending on where they lie on the celestial sphere. If you're really saying that you don't think it could be a star because you're under the impression that stars don't move below the horizon, then I can assure you they do.

It sounds to me like you saw a star twinkling near the horizon and then setting.

You mean the movement of the star moving below the horizon? Yes... stars move below the horizon.

You saw a star.

https://www.youtube.com/watch?v=ooeRUOZ0Gi4

No, the answer to the first question is "there's no reason to think those numbers should match". Asking the question in the first place requires some kind of misunderstanding about the big bang and/or observable universe, but it can be hard to pin down exactly what that misunderstanding is.

But if a question actually included the words "expands at the speed of light", it would be easy to identify that misconception, because that's not at all how expansion works. It doesn't have a speed. It's like increasing the scale factor of the universe, everything getting further apart from everything else, and a uniform dilation preserves distance ratios between things, which means the recession velocity of an object must increase with distance. Two objects can be expanding away from each other at any speed you want as long as they are far enough apart.

The distance at which things expand away from us faster than C is around 14.5 billion lightyears (the hubble radius). So the objects in the observable universe that are further than that have been expanding away from us faster than C ever since they passed that distance.

The observable universe is defined as containing everything we could have ever observed, not things that we could still receive a signal from if emitted "right now" in cosmic time. That is once again the hubble volume, which is just a sphere with r = the hubble radius.

Have you read Sean Carroll's writing on it? That'd be a better idea than posing this question to /r/space.

Beyond Falsifiability: Normal Science in a Multiverse

Or how about his 2+ hour long podcast episode titled "The Philosophy of the Multiverse"