- Two large satellites are predicted to have a >10% chance of colliding at 8:56pm on Thursday. If it happened, what would we be able to see from the surface of Earth, and what would the short and long term consequences be?
- What is the farthest back you could go in human history, take a child, and raise it in the modern day world and have it be a normal human?
- Am I properly understanding quantum entanglement (could FTL data transmission exist)?
- What share of Covid-19 patients suffers long-term impact?
- Why can we no longer see light after we turn off/extinguish the light source?
- If normal force cancels out the gravitational force on a flat surface, why do I still feel my own weight?
- What happens to time if an object completely stops moving?
- Why have the number of "bits" in commercial computer processors stopped increasing?
- Please explain superfluidity. How is it possible that a fluid has zero viscosity?
- Can other animal species have vision impairments like needing glasses?
- What do B Cells do in our immune system? What would it be like if we didn’t have them?
- Seasonal flu comes back every year, are they all different strains every year? wonder why we didn’t hear about “2nd wave”(other than Spanish flu)?
- Why airplanes fly? (Bernoulli or Conada?)
| Posted: 15 Oct 2020 01:37 PM PDT LeoLabs are predicting that two large satellites have an uncomfortably high chance of colliding at an altitude of ~1,000km on Thursday. (EDIT: Looks like the satellites passed each other without incident, thankfully.) Given their high mass and relative velocity, would a collision produce a flash capable of being seen from Earth, either with the naked eye or with a telescope (however powerful)? Will debris at that altitude make space exploration much more difficult, and if so, for how long? And a bonus question: what, if anything, could we do about it with such short notice, assuming we had access to whatever resources necessary? Thank you, space boffins. Edit: Sorry, I should have been clearer that the timezone for the collision estimate was reported in EDT, so the moment has now passed and it seems that the objects missed each other by as little as 10 metres. That being said, I'm still interested to know the hypothetical answers to the above questions for when situations like this inevitably occur again in the future. I'd also like to expand the scope of the "what could we do about it" question: rather than asking what we could do about this specific collision, in general what could we do about any potential collision of space debris? How much time would we realistically need, given the current state of technology, to mount a response to cope with something on this scale? How would that timeline change if, say, China, the US, and Europe all decided that avoiding a collision was priority number one and provided unlimited resources to solve the problem? [link] [comments]  |
| Posted: 15 Oct 2020 11:22 AM PDT Always wondered about this, and exactly when we became the same Homosapiens we are today. Thanks in advance [link] [comments]  |
| Am I properly understanding quantum entanglement (could FTL data transmission exist)? Posted: 16 Oct 2020 06:55 AM PDT I understand that electrons can be entangled through a variety of methods. This entanglement ties their two spins together with the result that when one is measured, the other's measurement is predictable. I have done considerable "internet research" on the properties of entangled subatomic particles and concluded with a design for data transmission. Since scientific consensus has ruled that such a device is impossible, my question must be: How is my understanding of entanglement properties flawed, given the following design? Creation: A group of sequenced entangled particles is made, A (length La). A1 remains on earth, while A2 is carried on a starship for an interstellar mission, along with a clock having a constant tick rate K relative to earth (compensation for relativistic speeds is done by a computer). Data Transmission: The core idea here is the idea that you can "set" the value of a spin. I have encountered little information about how quantum states are measured, but from the look of the Stern-Gerlach experiment, once a state is exposed to a magnetic field, its spin is simultaneously measured and held at that measured value. To change it, just keep "rolling the dice" and passing electrons with incorrect spins through the magnetic field until you get the value you want. To create a custom signal of bit length La, the average amount of passes will be proportional to the (square/factorial?) of La. Usage: If the previously described process is possible, it is trivial to imagine a machine that checks the spins of the electrons in A2 at the clock rate K. To be sure it was receiving non-random, current data, a timestamp could come with each packet to keep clocks synchronized. K would be constrained both by the ability of the sender to "set" the spins and the receiver to take a snapshot of spin positions. So yeah, please tell me how wrong I am. [link] [comments]  |
| What share of Covid-19 patients suffers long-term impact? Posted: 15 Oct 2020 12:51 PM PDT We know that the virus hospitalizes mostly elderly and those with pre-existing conditions. But how about the mild cases? We've all read stories about long term tiredness, damaged heart and lungs, confusion, forgetfulness (brain damage). So do we know anything about the numbers? 1%? 50% of cases? New York Times talked high numbers (30-50%) NYT but it's not clear to me how / if that applies to the general population. [link] [comments]  |
| Why can we no longer see light after we turn off/extinguish the light source? Posted: 16 Oct 2020 02:59 AM PDT A few months ago, I learned in class that light is a form of electromagnetic radiation and (if I'm understanding EM radiation correctly) that means that light is just visible energy. If I make a sound in a large parking lot, the sound lingers because the vibration bounces off the walls. Why is this effect seemingly nonexistent for light? [link] [comments]  |
| Posted: 16 Oct 2020 05:44 AM PDT I got this question from a student I teach high school physics to (we just started the chapter about forces), and I wasn't able to formulate a satisfying explanation for myself, can you guys help me out? [link] [comments]  |
| What happens to time if an object completely stops moving? Posted: 16 Oct 2020 05:23 AM PDT When I say stops moving, I mean without Earth's rotation, orbit, or any other motion it may go through. Just purely frozen in the universe. [link] [comments]  |
| Why have the number of "bits" in commercial computer processors stopped increasing? Posted: 15 Oct 2020 12:05 PM PDT In the 20th century, major advances in computing were marked by the number of bits the machine was capable of processing. 8 bit machines, 16 bit, 32 bit and then 64 bit. But it seems we never got to a 128 bit machine (or if we did it was never made commercially) why have commercial computers never adopted 128 bit technology? [link] [comments]  |
| Please explain superfluidity. How is it possible that a fluid has zero viscosity? Posted: 15 Oct 2020 11:08 AM PDT |
| Can other animal species have vision impairments like needing glasses? Posted: 15 Oct 2020 10:45 AM PDT |
| What do B Cells do in our immune system? What would it be like if we didn’t have them? Posted: 15 Oct 2020 01:06 PM PDT Hey! I'm learning more about immunomodulators and everything online is a bit too sciencey for me to completely understand. Specifically, I'm wondering what B cells actually do, and what our body/immune system would be like without them. I know a bit about T cells but B is a mystery [link] [comments]  |
| Posted: 15 Oct 2020 09:05 AM PDT |
| Why airplanes fly? (Bernoulli or Conada?) Posted: 14 Oct 2020 06:57 PM PDT https://www.youtube.com/watch?v=3KqjRPV9_PY I was watching that, but the explanation sounds like dark magic to me (which is fair enough, it is a pop-sci). My exact question is: What experiment can differentiate if it is indeed Bernoulli or Conada effect? [link] [comments]  |
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