Recent comments in /f/askscience
Durable_me t1_j4wnxq4 wrote
Reply to Whats stopping us from sending a probe into a black hole if we haven't already? by stealth941
If we could, the probe will never enter the black hole's event horizon from our perspective...
It will slow down to come to a halt just before the event horizon.
From the probe's point of view it will enter without any problem if the hole is big enough. (otherwise it will turn into spaghetti)
TheHumbleShaft t1_j4wnruw wrote
Reply to comment by TONewbies in Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology by AutoModerator
I believe it's because those wastes in the genitals often include sodium and potassium, or spare electrolytes and the idea is that the body rids itself of those electrolytes through the kidneys, and water follows because of osmotic pressure. If that happened through the anus, the large intestine would likely take up a large portion of that water and put it back into the recirculation and would also absorb the electrolytes due to diffusion so there would be minimal filtration and you would die of electrolyte imbalance.
In regards to urethra being near the anus, I think they're relatively close but you don't want them too close because feces is rife with bacteria and the urethra is an excellent environment for bacteria to multiply (dark, warm, moist) and you'd have near constant UTIs which could lead to kidney infection and damage. Some women actually deal with that fairly regularly, and is why women should always wipe from front to back after a bowel movement.
Karontu t1_j4wnbf8 wrote
Reply to comment by Weed_O_Whirler in Whats stopping us from sending a probe into a black hole if we haven't already? by stealth941
How is it slowing down? Is it intentional? I have always been told that in the vacuum of space once something is on a trajectory it will continue indefinitely unless something interrupts it.
Buddahrific t1_j4wma2y wrote
Reply to comment by roosty_butte in What happens to the energy of sound in space? by full_hammer
Pressure plays an essential role in sound (sound is pressure), so it's hard to separate the two. A vibrating tuning fork would transfer kinetic energy to anything that gets close enough to touch it, including a pocket of air that is somehow held together in a vacuum. If you had a microphone inside that, I think it would pick up those vibrations as sound.
[deleted] t1_j4wm42k wrote
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[deleted] t1_j4wm1es wrote
Reply to How does lightning illuminate the sky? by AverageMan282
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peoplerproblems t1_j4wlqp9 wrote
Reply to comment by CrustalTrudger in Extinction of the Dinosaurs: What did I miss? by cakedayCountdown
So you got me curious about multiple factors relating to the current and previous extinction events.
O-S was climate and atmospheric composition, greenhouse effect of volcanos, and loss of oxygen.
The Devonian event(s) were ecological, but I can't find much on it.
P-T was ocean acidification, oxygen loss, greenhouse caused by volcanism
T-J was again, acidification, climate changed, and oxygen loss.
K-G, again, acidification, climate change, but I can't find atmospheric composition.
Regardless, it appears that the extinctions occur once those worldwide changes start, regardless of the cause. What I'm curious about now is if there is any evidence at how inhospitable the planet was by the end of the extinction events.
[deleted] t1_j4wl783 wrote
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kingsillypants t1_j4wl6xn wrote
Reply to comment by ellipsis31 in What happens to the energy of sound in space? by full_hammer
And into pushing you back into the opposite direction (Newton's 3rd law ).
[deleted] t1_j4wk64d wrote
Reply to Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology by AutoModerator
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[deleted] t1_j4wjmuy wrote
Reply to comment by GolfballDM in What happens to the energy of sound in space? by full_hammer
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extropia t1_j4wjgoj wrote
Reply to comment by stealth941 in Whats stopping us from sending a probe into a black hole if we haven't already? by stealth941
Unfortunately movies like Interstellar (which I love btw) make it seem like simply entering a black hole would reveal all sorts of secrets of the universe to an observer. All we really know is that most of our physical models break down in there, and without a massive lineup of experiments and machines to conduct them to take into the black hole, let alone the current impossibility of doing so, it would be akin to you doing 5 tabs of acid and then telling the rest of us 'you've figured it all out'.
The latter would be a lot more enjoyable.
Coquenico t1_j4wjdb4 wrote
it's simply because the earth is a sphere that's spinning
considering a spinning sphere, then there's an axis; that's your north-south direction. and then perpendicular to that are planes within which things are spinning -- if you're somewhere on the surface of the earth you're moving in a circle -- that's your east-west direction
note that the notion of north etc is completely unrelated to the sun, it only has to do with the earth's rotation
citizenp t1_j4wj02q wrote
Reply to Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology by AutoModerator
I asked this about DNA and got an education on how DNA is a small part of our make up. So, are there any things we can measure/count to say that two plants or animals share ??% of these things and are therefore the same species or different species? Or does whether or not some things are species are just voted on. Seems like it would be more scientific to count than vote.
cheekychessie OP t1_j4wittd wrote
Reply to comment by redligand in What specifically keeps viruses from moving from human to animal or vice versa in most cases? by cheekychessie
Wow first answer is a champion!! So detailed and really makes sense. Thanks so much.
Follow up question, for something like covid. Was it just waiting to find a human with a similar enough protein match to make the jump?
[deleted] t1_j4wi6as wrote
Reply to Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology by AutoModerator
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roosty_butte t1_j4wi5a2 wrote
Reply to comment by Buddahrific in What happens to the energy of sound in space? by full_hammer
Nah, I mean as a purely theoretical situation. The bubble of air is not affected by the vacuum of space.
Buddahrific t1_j4whq4h wrote
Reply to comment by raff7 in What happens to the energy of sound in space? by full_hammer
That's assuming you didn't blow your eardrum completely in the transition to a vacuum. Which is possible if the pressure differential was maintained (pressure reduced on the inner ear at the same rate as outer).
[deleted] t1_j4whfdx wrote
Reply to Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology by AutoModerator
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Baby-saint OP t1_j4whbuf wrote
Reply to comment by SethSky in What exactly happens in your body when you touch or consume a radioactive substance i.e U235 or Pu239. What happens on the cellular level and how the brain & nervous system deals with it? by Baby-saint
I mean how Marie Curie's body responded to it, what information did the cells delivered to brain and how brain perceived it in such a case where it is strange energies penetrating thru and rapid mutating. she lived a lot of years in a radioactive environment and matter of fact is before it was discovered how bad it can be for exposure I am sure she and her team had enough.
7eggert t1_j4whavq wrote
Reply to comment by CrustalTrudger in Why is it that the cardinal directions are perpendicular? by [deleted]
I remember seeing a documentary about Indonesian navigators, they do use the rising stars as their point of reference while we use the polar star. Also I read about the temple in Jerusalem and the Tabernacle) having had the door to the east for the same reason. So your scenario isn't that hypothetical, it did (and probably does) have real life application even on earth; using "north" or magnetism is just one of the possible and valid choices for describing directions that were used.
TL;DR: If you are interested, you'll be able to find examples on earth other than "magnetic north is up".
[deleted] t1_j4wh8gq wrote
Reply to Whats stopping us from sending a probe into a black hole if we haven't already? by stealth941
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NDaveT t1_j4wg45g wrote
Reply to comment by NeuralParity in Whats stopping us from sending a probe into a black hole if we haven't already? by stealth941
You could, yes. The trick would be getting relay satellites to those intermediate points and keeping them there.
redligand t1_j4wfxfr wrote
Reply to What specifically keeps viruses from moving from human to animal or vice versa in most cases? by cheekychessie
It's very crudely similar to the reason you can't get an organ transplant from your dog despite sharing the same organs. There are certain molecules (mainly proteins) that exist on the surface of animal cells that allow other species to recognise them as foreign. By and large the same kinds of proteins (we say they are homologous) exist on the surface of your dogs cells and yours but they are sufficiently different that your body will recognise them as "not mine".
Viruses exploit their hosts by binding to proteins on the surface of cells. Often these proteins are sufficiently different between species that a virus cannot recognise "Protein X" in a human, even though it operates by binding to the homologous 'Protein X" in a dog. However, it is certainly possible for viruses to evolve to recognise both dog and human Protein X. This can happen most easily when humans and populations of sick animals live closely together for long periods of time. It's one of the leading hypotheses of the emergence of covid, HIV and ebola (to name a few high profile but far from comprehensive examples).
The viruses don't do this on purpose of course. They're mutating randomly all the time. But if a few virions by chance develop a mutation that makes them less selective wrt the differences between Protein X across species AND they have the opportunity to spread to that new species, they can jump the "species barrier" and become a new infectious agent in a new set of hosts.
[deleted] OP t1_j4wo20y wrote
Reply to Why is it that the cardinal directions are perpendicular? by [deleted]
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