Hi, I’m sbird! I like programming and am interested in Physics. I also have a hobby of photography.

previous scheep on lemmy.world: https://lemmy.world/u/scheep

  • 6 Posts
  • 40 Comments
Joined 2 months ago
cake
Cake day: June 12th, 2025

help-circle





  • On a tight budget, definitely look used wherever you can. You can get some banger deals on used computers, monitors, projectors, speakers, etc.

    I would reckon either a cheap laptop, mini pc, or used workstation would work as a device to play movies. Alternatively, if you happen to have a playstation, you could also use that as a dvd player.

    For speakers, the Edifier speakers are pretty good value. The 1280DB is under $200 and you can always hunt for sales. Make sure to get an active speaker so then you don’t need to get a separate amplifier. If you don’t fuss about sound quality, the teeny tiny pebble speakers are decent and can be found for very cheap too.

    For display, I would go for a used projector. For projectors, depending on how big your room is, try to look for short throw projectors (basically means big screen with a small distance).

    Another route would be a cheap monitor, which although smaller than what a projector can output, is still quite a bit bigger than a phone screen. It would work better than a projector if you have lots of windows and tend to watch movies when there’s a lot of sunlight (if you watch movies at night and/or you don’t have many windows, projectors work fine)





  • The IAU did come up with a boundary: having enough mass to clear (most of) its orbit. That’s because simply mass and roundness are pretty arbitrary numbers that could be set to anything, while clearing the orbit is decently well-defined, at least mostly. It’s a good post to set as the lower limit for the mass of planets. That’s why Ceres is no longer considered a planet as well, there’s millions of asteroids in the Asteroid belt and it’s not massive enough to get rid of them. Similar reasoning goes for Pluto, Eris, Makemake, and their friends in the Kuiper belt. They’re not massive enough to clear their orbits of all those asteroids and other small objects.

    Well orbits and neighbours and such I would argue is very important in astronomy. If you were all alone in the void of space and there is nothing else that exist, there wouldn’t be anything to compare against. The idea of relative size, mass, rotation, position, and even time wouldn’t really exist. The whole idea of moons is that it orbits planets, no matter its size, composition, or mass as long as it was naturally formed (hence why the ISS is not considered a moon, it’s an artificial satellite). Planets, by definition, are objects that orbit stars. Moons don’t orbit stars and hence cannot be planets.

    I’m not very good with analogies, but here me out. Imagine the hands of a clock, all alone with no clock for the hands to tick. They may as well be pointy bits of metal, they are not hands without the clock. Just as moons are but rocks when without a planet, or how planets are not so without a star.



  • One of the main criteria for a planet is that it orbits a star. Moons don’t orbit stars and hence not planets. If Earth was orbiting Jupiter, it would be a moon but not a planet. Moons could harbour life too! Titan (which orbits Saturn) has an atmosphere, and Europa could have subsurface oceans under all that ice.





  • But how round is round enough? What about the millions of asteroids floating in the asteroid belt, many of those are spherical. Should they be considered planets? No, of course not. We can’t just call everything that looks like a sphere a planet. That’s ridiculous.

    It was decided that planets 1. should have a stable orbit around a star 2. have enough mass to become spherical (that’s your point) 3. massive enough to clear its orbit, which in our Solar System means there are 8 planets. Pluto is surrounded by millions of Pluto-like objects in the Kuiper belt. Pluto, as well as its buddies Eris, Makemake, etc. are classified as dwarf planets because they are not massive enough to have cleared their orbits.

    Dwarf planets are cool too, they might even have life in subsurface oceans under all that ice :0

    Moons are not planets because they don’t orbit a star. Stars are pretty well-defined, objects where there is enough mass for nuclear fusion to occur. Planets are definitely not stars, so moons are not planets.





  • Moons are defined as naturally-formed objects that orbit a planet. Natural satellites, basically. What’s wrong with that definition? The Moon is a moon, but Pluto is not. Moons don’t have to be a fixed size, Earth’s moon is relatively big compared to the planet it orbits, Ganymede is larger than Mercury, and some moons are teeny tiny. If you tried to classify them based on size, you’d have a million different categories.


  • And to add,Jupiter and Mercury belong in the same category as in they both orbit a star (the Sun in this case), both have enough mass to be spherical, and both have clear most of their orbits.

    But the category of planets has sub-categories. Mercury is a rocky terrestrial planet while Jupiter is a gas giant as the former is smaller and rocky while the latter is large and made of mostly hydrogen and helium gas. Gas giants can also be called “Jovian planet”, but Jove is just an alternate name for Jupiter (the god) so you’re basically calling Jupiter a “Jupiter planet” which I think is a bit ridiculous but whatever it’s fine. Both are still, of course, planets. It’s like a large tree and a sunflower. Both are still considered plants, but certainly in different subclasses of the category of plant.

    Dwarf planets, although not proper planets, are still very interesting objects that could even harbour life in oceans below their icy surfaces. Also, Pluto is not alone in the dwarf planets classification. There’s also Eris, Ceres, Makemake, and probably thousands more we haven’t discovered yet!