Hey folks! Here’s a pinned post where you can ask science questions!
Here’s a quick rundown of what this post is and isn’t:
- This is a place where you can ask science-related questions!
- This is a place to provide science-based answers to others’ questions!
- This isn’t reddit’s askscience community. By this I mean we don’t have the resources (or, really, desire) to vet users’ credentials, and you shouldn’t expect that whoever is answering your question is necessarily an expert. That said, this community does have a large share of professional scientists and engineers, and I’m hoping that those folks will be interested in sharing their expertise when they can.
- This isn’t a place to ask for medical advice – since we can’t vet qualifications these kinds of questions won’t be allowed here in the interest of preventing harm, and I’ll remove any comments that ask personal medical questions. If you have a question about medicine that’s not asking for advice, that is fine and allowed.
- This isn’t the only place on this community where you’re allowed to ask questions! If you have a question related to another post, ask in the comments there. If you have a question not related to another post, I’d like it if you tried asking here first (to help this thread gain some traction), but you’re also free to ask in a separate post if you’d prefer (or both).
I’m going to post this inaugural thread with no set expiration date. I’m currently thinking a new thread maybe every 2–4 weeks, but I’d like to see what the volume of comments here ends up being like before deciding for sure.
I’ll start us off with a biology question:
One thing I’ve always been really interested in is biomineralization, especially as it relates to single-celled organisms like diatoms and magnetotactic bacteria. But it seems like moving solid crystalline materials around inside a cell (or from the inside out, I assume, in the case of diatoms?) would be much more difficult than moving around liquids or bendy organic molecules. How do cells manage to do this?
I’m not a biologist but I do research with “mineral” types of materials. It does indeed seem much more difficult to transport solids than liquids within the cell. But from what I know cells have organelles called vesicles to move things around, and nanoparticles are plenty small to fit inside them. With some brief searching I found this article https://www.nature.com/articles/s41467-021-24944-6 that shows the process in diatoms using cryogenic transmission electron microscopy. So they imaged this process directly. They actually found that this species deposits the silica directly into the cell wall. So for long thin structures they do transport the Si-compounds in liquid. I’m sure you can find further reading in this article’s references.
Okay so, it’s common for people to talk about distant stars as appearing one way because the light takes (mi|bi)illions of years to get to us, and that makes perfect sense to me… But when they go on to say that, for instance, Betelgeuse has already gone supernova but we won’t see it until the light gets to us…
According to the principle of the relativity of simultaneity, since the speed of light is the speed of causality, wouldn’t it be a bit more accurate (though definitely more confusing to the public) to say that the stars actually are as we observe them, but that the star is far enough away that traveling to it, even instantly, would basically require significant time travel forward? I guess it would just be a different way to talk about “the present” in relativistic terms, which is only difficult because our languages never evolved to handle the concept.
What you think?
