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gandalf_der_12te

@ gandalf_der_12te @discuss.tchncs.de

Posts
93
Comments
3224
Joined
2 yr. ago

Contact me on matrix chat: @nikaaa:tchncs.de

  • You have to be orchidding me!

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  • downvoting because it's not really true what you said. sure there's always exceptions in biology that don't fit into the species concept, but i dare say for lots of living beings, including practically all eukaryotic organisms, with very few exceptions, it's a good categorization scheme.

    the exceptions you mentioned (asexual reproduction; edge cases where interbreeding is difficult but not impossible) are the exception, not the rule. that doesn't make the rule meaningless though.

  • You have to be orchidding me!

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  • yes. that's why star trek is bullshit in that regard. if we ever met extraterrestrials and they happen to look anything like humans at all, the biochemical differences will be so severe that there's absolutely no chance at all that they would be able to produce viable offspring with humans.

  • Sad Ganymede noises

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  • Koreans believe fans to be dangerous to use while sleeping

    tbf i believe that too (but about ACs and not fans) and i'm not korean. the reason i believe this is because of my real-life experiences. When AC is running, it typically gives me the sensation that the air it gives off is not just cold, but creepy cold, like an iron rod is not just hard, but hard enough to smash somebody's skull with it. The same intensity is the coldness from the typical ACs that i've experienced. At least some of them.

  • Job Security

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  • That was the original sin: People got clever and discovered technology, and now we have to work blue-collar jobs.

  • Job Security

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  • It's true. You can create infinite bullshit jobs just to keep the population busy. And some people are even stupid enough to fall for it, saying "some employment is better than no employment" because people fundamentally think that work is the most important principle in life and people only deserve to exist as long as they're working.

  • Alchemy is so hot right now.

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  • Fun fact: The chemistry of oils is called "Öl-Chemie" in german which sounds almost like alchemy.

  • Sad Ganymede noises

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  • Because there’s multiple asteroids that technically have one, albeit extremely thin ones.

    can you please link an example?

  • PFP Evolution

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  • People have inferiority complex when they're young so they feel they need to brag with how "badass" they are.

    When you're older you understand that true wisdom is in the little things, in the things that don't look like much but make up a healthy society.

  • Sad Ganymede noises

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  • I always suspected that the discussion about letting Pluto stay a planet is especially relevant in the US since Pluto was the only planet to be discovered by US scientists ... so it's a point of national pride.

  • Sad Ganymede noises

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  • There is no objective criteria for what a planet is and isn’t.

    There is, though, or rather there should be another one.

    The official definition says it's a planet if it's big enough to be round, which IMHO is a bullshit definition because nobody cares whether your object's round, as in, for practical settlement purposes.

    What's important though is that it's large enough to hold an atmosphere (at least if it had one). That's only the case if the gravitational field is strong enough, which is the case roughly for objects of mass starting at around 10^23 kg. That definition fits surprisingly well the current actual classification of what is a planet and what isn't, though.

    Edit: I want to elaborate a bit more on this. Basically, if you consider a planet that has an atmosphere, like Earth, you see that the atmospheric density/pressure decreases exponentially with height. The concept of Scale Height discusses this: The atmosphere decreases exponentially, but if you take the total mass of the atmosphere and divide it by the density of the atmosphere at sea level, you get a height. That means, if the atmosphere had constant density up to that limit height and then cut off to zero, it would have the same mass as the actual atmosphere has. For Earth, that atmospheric scale height is about 8 km, about as high as the highest mountains on Earth btw.

    The same concept of a scale height also exists for the gravitational field. Planets have a gravitational potential, which is formally the integral of the gravitational acceleration from ground to infinitely far-away. But you can simplified imagine it as: If the gravitational field would be constant up to a limit height and then would cut off to zero, that's the scale height. For Earth, that gravitational scale height is about 8000 km, or about 1000x the atmospheric scale height.

    The consequence of that is that Earth can hold an atmosphere neatly. Because for every gas molecule in the atmosphere, it is affected by the field of gravity strongly enough to be certainly bound to Earth. We take that as a granted, but consider this:

    If the atmospheric scale height of another, fictional planet, was also 8 km but its gravitational scale height was only 4 km, then that would mean that a large part of the atmosphere would be exposed to being above-the-cutoff-height for gravity, so it would be effectively un-affected by gravity and would float away freely from the planet. This would actually not only imply that the planet would lose half of its atmosphere, but all of it. This is because, when the planet loses half its atmosphere, the atmospheric scale height actually doesn't decrease at all. This is because it's not like the atmosphere becomes less high, instead it just becomes half as thick everywhere. That also includes the ground level. So you have half the total mass of the atmosphere, but also half the thickness on ground level, so if you divide this, it's still the same atmospheric scale height (!). This would mean that again, half of it would be above the gravity field and would escape again, and this process would repeat indefinitely until the planet has lost practically all of its atmosphere. Thus the planet could not hold an atmosphere.

    That's why there's an important relationship between the gravitational potential of a planet and the fact whether the planet can hold an atmosphere at all. This isn't just about how big the atmosphere can be in total, but whether there's any atmosphere at all. Below a certain minimum planet mass, that's completely impossible. Above, it's possible.

  • Removed

    White House Official: Why do we have the right to take Greenland? Because we live in a world governed by strength, by power. We have power. Nobody can fight the United States militarily

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  • Soon:

    i.e. trump only thinks about conquering but never about the bureaucratic difficulties in actually running another country. he already has problems running his own country, he basically doubles the difficulties if he takes another country.

  • European phones - Choose for youself

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  • other phones are cheaper mostly due to economies of scale, though. like, idk, china makes a few million phones at once, while in europe they make, what, a few thousand phones at once?

  • European phones - Choose for youself

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  • does anybody have experience with the Jolla C2 Community Phone?

    the price is listed as 285€, which is about the maximum i'd be willing to pay for a phone. does the device work well? does it run smoothly? does the OS work well enough? (it's some custom linux-based OS with android app compatibility, they write on their website)

  • Vienna would need about 150 km² of solar panels to produce enough electricity

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  • yeah it's sth like 1% of humanity's total land area usage (i did that math last week). 97% of humanity's land area usage go to agriculture

  • Vienna would need about 150 km² of solar panels to produce enough electricity

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  • yeeah, i had that thought too. thing is, it's significantly easier to build solar parks on flat ground than on rooftops, simply because of installment cost.

    i remember seeing a plot that says that installing rooftop solar is about twice as expensive than flat area solar (for the same kWp), but i can't find the diagram anymore, after looking for it on the internet for 5 minutes.

  • Vienna would need about 150 km² of solar panels to produce enough electricity

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  • within city limits

    it was more a size comparison, i didn't really mean to say that it has to be within city borders. cables can cross political borders, of course.

  • Vienna would need about 150 km² of solar panels to produce enough electricity

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  • yeah i included manufacturing because i was like "most big factories are in or close to big cities, because that's where the workforce lives, so it makes sense to build factories there. and factories need energy."

    ofc small variations in power are a given, because you have things like electricity being more efficient than oil, so you need fewer kWh, and such.

  • Metal Exclusionary Radical Astronomy

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  • any good astronomer knows that the real binary is ordinary matter / dark matter

  • Showerthoughts @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    Vienna would need about 150 km² of solar panels to produce enough electricity

  • pics @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    Stucco relief at the Château de Fontainebleau

  • Collapse rule

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  • interesting. but what if i want to make a mixture of vector graphics with a small portion raster graphics. the PDF would probably be smallest, because it will store all the vector graphics as vector graphics and only the small part raster graphics as raster graphics.

  • friendship ended with pi, now sigma is my best friend

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  • one could even call it my sigmature move

  • Science Memes @mander.xyz
    gandalf_der_12te @discuss.tchncs.de

    friendship ended with pi, now sigma is my best friend

  • Showerthoughts @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    In special relativity, proper time is like TIME in htop (linux process user time)

  • Lemmy Shitpost @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    Study Featuring AI-Generated Giant Rat Penis Retracted, Journal Apologizes

  • Lemmy Shitpost @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    suss

  • Lemmy Shitpost @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    i can't handle coffee

  • ich_iel @feddit.org
    gandalf_der_12te @discuss.tchncs.de

    Ich_iel

  • ich_iel @feddit.org
    gandalf_der_12te @discuss.tchncs.de

    ich_iel

  • 196 @lemmy.blahaj.zone
    gandalf_der_12te @discuss.tchncs.de

    The Abyss

  • Today I Learned @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    Vendetta was outlawed in germany around 1500

  • Today I Learned @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    Agriculture uses 98% of humanity's land usage

    ourworldindata.org /cdn-cgi/imagedelivery/qLq-8BTgXU8yG0N6HnOy8g/0389217f-d8a0-4806-ddea-98b9d4089d00/w=12544
  • Science Memes @mander.xyz
    gandalf_der_12te @discuss.tchncs.de

    Sea Level

  • memes @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    Measure Twice, Cut Once

  • Microblog Memes @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    the letter Q

  • Ask Lemmy @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    physics question: cosmic expansion

  • Lemmy Shitpost @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    dripping mfer

  • Showerthoughts @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    the US could be the next italy

  • 196 @lemmy.blahaj.zone
    gandalf_der_12te @discuss.tchncs.de

    "Earning a living" does not rule

  • politics @lemmy.world
    gandalf_der_12te @discuss.tchncs.de

    Trump praises Mamdani after White House meeting: "I want him to do a great job"

    www.cbsnews.com /newyork/live-updates/trump-mamdani-meeting-white-house-new-york/