this post was submitted on 08 Jul 2026
906 points (99.5% liked)

Science Memes

20668 readers
2108 users here now

Welcome to c/science_memes @ Mander.xyz!

A place for majestic STEMLORD peacocking, as well as memes about the realities of working in a lab.

Meta Post Tags

Rules

  1. Don't throw mud. Behave like an intellectual and remember the human.
  2. Keep it rooted (on topic).
  3. No spam.
  4. Infographics welcome, get schooled.

If you are here asking: "Is this a science meme?"

Probably, yes. We use the Dawkins definition of meme: a replicating idea, not just an image macro with a fact on it. A good post here doesn't need to teach you something. It needs to make you ask something: who, what, where, when, and especially why or how.

Science isn't a filing cabinet of facts, it's a conversation. For example, a photo of an eel or other localized wildlife counts because most people never see one, and wonder is the first step of inquiry. A car meme counts if it makes you curious about what's under the bonnet. If you want to talk about something you noticed in the world, chances are someone else wants to talk about it too.

We moderate for vibe, not category. Pruning is light, especially where a post creates interesting discussion. Experimenting is encouraged.

See the pinned paper on Shitposting as Public Pedagogy if you want the academic case for why this works.

Research Committee

Other Mander Communities

Science and Research

Biology and Life Sciences

Physical Sciences

Humanities and Social Sciences

Practical and Applied Sciences

Memes

Miscellaneous

founded 3 years ago
MODERATORS
Sal@mander.xyz
fossilesque@mander.xyz
SciBot@mander.xyz
fossilesque@lemmy.dbzer0.com
906
Roses (mander.xyz)
submitted 1 day ago by fossilesque@mander.xyz to c/science_memes@mander.xyz
29 comments fedilink hide all child comments
 
you are viewing a single comment's thread
view the rest of the comments
[–] gandalf_der_12te@feddit.org 2 points 1 day ago* (last edited 1 day ago)

Basically, on a cosmological scale, distance and velocity are connected

yeah btw to comment on this: this phenomenon is probably more important than it seems at first glance. because it implies that, while there is neither an absolute position nor an absolute velocity in relativity theory, there is a connection between position and velocity. so, for each position in space, there is an associated (finite) zero velocity, or reference velocity, which is the velocity of the cosmos at that location. or at least that's what i'm lead to believe.

now, this is not at all obvious. one might argue that that's bullshit, frankly, (because it very obviously contradicts special relativity), but it appears at least 3 times in various aspects of standard models of cosmology:

  • for one, contemporary microwave background. it's said to be isotropic (and has the shape of a black body radiation) but only if the observer moves with a certain velocity. if you move extremely fast in either way, one side gets blueshifted while the other one gets redshifted, so it's not isotropic anymore. there's exactly one (finite!) velocity for which it is most isotropic, which is the "average velocity" of the radiation.
  • then there's the whole question of how a vacuum energy could possibly be lorentz-invariant. the way i see it, if there is radiation in space everywhere, then that would have to be similar to microwave background (just at another frequency). so it again would have to have a certain average velocity. note that this is different from the previous point because while the previous point uses other objects as reference frame (that might not be present in an alternative universe), this one does not. you cannot have a universe with the same laws as ours that's completely empty of vacuum energy, so there's always some reference frame.
  • then there's the issue that if you go really far back in time, the cosmic expansion is not lorentz-invariant. well, at least not if you look at this curve:

if you tilt it somewhat, it's not isotropic anymore. because while expansion rate is accepted to vary with time, it should be homogenous in space. now, if you do a lorentz-transformation, these two things cannot hold at the same time. so, cosmic expansion wouldn't be lorentz-invariant?