Danijel Gorupec

Because as I am falling through the horizon, at one moment my legs are below horizon and my head is above it. Does it mean that my blood cannot circulate any more - the blood from my legs cannot return to my heart? If so, I would definitely notice I crossed the event horizon (disproving the claim 2). Or, my blood can continue to circulate, in which case also the rope can be dipped and removed in/out of event horizon (disproving the claim 1).

I am imagining orbiting a supermassive BH just above its event horizon, then lowering a rope (or better a rod) - it does not have to be a very long rope/rod... I don't understand why I should be dealing with strong forces here?

Long time no chat... I was trying to use AI to help me reconcile the two claims I commonly hear, but without success. Maybe someone here can help me better: claim 1: If you lower a rope below event horizon you are not able to pull it back claim 2: You can cross the event horizon of a supermassive black hole without even noticing. The two seem incompatible to me, but LLMs do not seem to be bothered.

Thanks CharonY, nice answer. One more question: you mentioned large differences in genome sizes even within related eukaryotic species - does it mean that genome size can change in large steps (I suppose this is more likely than series of many small unidirectional steps)?

I hope I don't ask something dumb... Are there studies to check if, on average among species, genome size increased in last tens of millions of years? Would you expect that evolution continuously increases genome sizes, or did we reach some sort of equilibrium already?

To prepare bread dough, I mix flour and water. They say that water hydrates starch and protein molecules in the dough... What this 'hydrating' mean at the molecular level? I am imagining that water molecules make short-lived bounds with large dough molecules (carbohydrates and proteins). If so, does it mean that those bounds (between water and large molecules) are stronger and longer-lived than bounds between water molecules themselves? What is the thickness of this bound water layer - is it one molecule thick? There is also free (unbound / bulk) water in the dough. I imagine there is some sort of equilibrium between bound and unbound water - that is, you cannot have a dough that only has bound (and zero unbound) water? Still, I imagine that in drier doughs, larger proportion of water is bound and smaller proportion is free? Yeast needs water - I guess it lives inside water - is this the free (unbound) water where the yeast lives in? Btw, I am interested in all things dough, so if you have anything else interesting/important to mention, go ahead.

The derivation you are mentioning... is it considering some sort of plane gravitational waves, or more general? As I understand you, you are also talking about near-observer perturbations? Otoh, the array of clocks, I was mentioning, is distributed.

I was indeed interested in weak gravitational waves... I would be surprised if the theory only predicts disturbances in spatial dimensions, and not the time dimension. Because I am under impression that the theory treats space and time on more or leas equal footing. Anyway, I am now thinking about what you said, if gravitational waves indeed can cause only (or predominantly) spatial disturbance, can then there exist a different type of gravitational wave that only (or predominantly) causes time disturbance? @swansont Thinks for the link.

As a gravitational wave passes though a constellation of precise clocks, would it be possible, at least in theory, to detect its passage by measuring time difference between clocks? If so, is it harder to make such measurements than to measure spatial distortions?

Could two or more space shuttles do it - by refueling in the orbit? At least an one-way trip... You park one shuttle in the orbit, and then use other(s) to bring more fuel.

Does it mean they are using gamma ray lasers? Can you see anything in gamma light without destroying it?

If I understand the task correctly... it is to estimate the moon distance on that exact day (it should be somewhere between 362600 and 405400km). You can take the moon and sun diameter (both fixed) from any external source.... The interesting part, imo, would be to estimate the error of your calculation.

I suppose your relative is aware that it is very easy to check if he sourced the answer from the internet. So, he probably did not have an intention to fool you... I guess he would change the wording if he really wanted to deceive.

Did you watch as it was happening? Was it fast or slow? I recently saw a video of some kind of sea slug catching a sleeping fish... by very slowly enveloping the fish in some sort of extendible bag... I was very impressed, but forgot to remember the slug name to learn more about it.

Hmm... I was supposing that 'not even light' is simply used to explain why it is called a 'black' hole. Most of the time, however, I guess, the phrase is just repeated without much thinking.... maybe we should not overthink it either.

Afaik, the one way will aid to directional stability, the other one will hinder it. When ribs push the mud outward, it aids the directional stability (that is, forces try to straighten the tire path). Normally, on a tractor, you mount the tires to push the mud outward if tires start slipping while the tractor is pulling forward. [But, I guess, if you use the tractor to brake a pushing cargo, such normal rib alignment might make your steering more difficult.]

Hmm... searching further, I found the following quote on Wikipedia: "The larger basal cell will give rise to the suspensor, which connects the embryo to the endosperm so that nutrients can pass between them." ( https://en.wikipedia.org/wiki/Embryo ) "suspensor" seems to be a term, so I found several links explaining it in some details (googled for 'seed suspensor'). Two of them are listed below: https://research.mcdb.ucla.edu/Goldberg/research/Pdf/sdarticle.pdf https://en.wikipedia.org/wiki/Suspensor Quote form the first link: "For example, the suspensor pushes the embryo proper into the endosperm cavity and connects the embryo proper to surrounding maternal and endosperm tissues - serving as a conduit for nutrients and growth regulators required for embryonic development" It seems, the 'suspensor' might have an active transmission mechanism, but the nature of it may not be known yet. However I am not sure if 'suspensor' is really the answer to my question because: the 'suspensor' seems to only exist for a very short period during the very first phase of embryo growth - I am not sure if all the nutrients from the endosperm are absorbed during that time. The 'suspensor' might only consist of a few cells. Subcellular outgrowths might have a role in absorbing nutrients (if I understood correctly). I also guess, something there, 'suspensor' perhaps, should release enzymes to cut the starch into simple sugars. For my second question, I didn't find a valid answer - from the internet readings, I cannot deduce if plant root can absorb glucose or not. I also cannot find any info if plant roots can emit enzymes to transform starch into simple (absorbable) sugars. However, when I think about it, I would guess the answer is NOT - if plants would be able to absorb starch through their roots, I would expect to see more 'predatory' behavior among plants. Anyway, I am abandoning this investigation as it seems to require a knowledge well beyond my level.

I would expect more likely for such a sub to surface than not. Hull implosion seems to me like (it should be) the least expected fault.... In fact, I considered the underwater search like some sort of wasting resources that could be used for the surface search. That said, I am unpleasantly surprised that the sub did not have any orange-colored part. Cannot think of any reasonable explanation.

When a plant seed germinates, how exactly does a germ access nutrients from the endosperm? Does it grow like a tiny roots into the endosperm? Can plant roots absorb starch (or at least break the starch into sugars before absorbing)? For example, if I mix wheat flour into ground and then seed wheat there, will this wheat be able to access nutrients from the flour?

Self-reported or measured symptoms?

Thanks for your comments... I didn't expect strict answers in the first place. For me, the most interesting part in your comment was about 'redshift' - are you talking about measured or calculated effect?

Thanks Markus... Because gravitational waves carry energy, I would suppose that they also carry momentum (Or not? I have a hard time imagining this). If gravitational waves do carry momentum, and if some source is emitting gravitational waves directionally (like a directional antenna), then I suppose the source will be receiving impulse in the direction opposite to the direction of emitted waves (possibly propelling itself through the space).

Few questions based on the analogy with light/sound waves. I suppose most cannot be answered strictly, but at least give me your hunches. 1. Should I expect that gravitational waves may reflect when they hit some sort 'wall'? Can such wall exist? Can we have phase-change and non-phase-change reflections? Can you suggest a 'wall' (either active or passive) that causes phase-change or non-phase-change reflection of gravitational wave? 2. I suppose gravitational waves can interfere? Is this a linear or non-linear process? 3. Can we imagine a standing gravitational wave? Can we imagine resonant cavities for gravitational waves (possibly allowing amplification)? 4. If we have multiple controlled sources of gravitational waves that act near-coherently, can we employ beam-forming - thus making a directional source of gravitational wave? 5. If directional gravitational antennas are possible, will such an antenna experience an impulse to the opposite side of the main gravitational lobe?

But do we have any estimation how much denser those galactic halos are compared to intergalactic space (regarding the DM density)? I mean, did galactic DM halos just started to form or is it that all the DM is already clumped in galactic halos?... I guess, from galaxy rotation curves we can only infer the difference in those densities, not the absolute densities (thus we can only infer the lower limit for the amount of DM)? I think Genady once argued that general relativity can set an upper DM density limit, even if the DM is near-uniformly distributed through the whole space (although, I am not sure if the dark energy factor would mess up such an calculation).