Can anything in the universe travel faster than the speed of light? |
- Can anything in the universe travel faster than the speed of light?
- Why the exhaust gas of a rocket engine (or a jet engine) flows faster when the cross section area of the exhaust nozzle increases?
- What powers a virus' "injection" mechanism?
- Is anesthesia medication universal for animals and humans?
- What engineering improvements allowed the LTE standard to support higher data download rates when compared to 3G technologies such as HSPA & CMDA2000?
- How can we be sure that radiocarbon dating is accurate?
- Why noncompressible fluid has higher velocity when moving through smaller cross section area?
- How does the rapid covid test kit work?
- Are there other acidic pools like the ones in Yellowstone?
- Dumb question: Do space vehicles have self destruct buttons?
| Can anything in the universe travel faster than the speed of light? Posted: 24 Sep 2021 03:49 PM PDT |
| Posted: 25 Sep 2021 05:10 AM PDT So I was doing some personal study on thrust, and while reading about the convergent-divergent nozzle of a rocket engine, I read that when exhaust gas exiting the combustion chamber reaches Mach 1, the exhaust gas becomes compressible, and the velocity of compressible fluid (in this case the >Mach 1 exhaust gas) is directly proportional to the cross section area of the nozzle. When we talk about the flow rate of a non-compressible fluid body through an pipe, we acknowledge that the velocity of the non-compressible fluid increases when the cross section area of the pipe decreases. So why, when a fluid turns from non-compressible to compressible, the rule of flow rate changes to the velocity of the compressible fluid increases when the cross section area of the pipe increases? What makes compressible fluid different than non-compressible fluid for such change in the rule of flow rate to happen? [link] [comments]  |
| What powers a virus' "injection" mechanism? Posted: 24 Sep 2021 07:14 PM PDT I am not sure all viruses inject into the cell but i believe some make contact with the surface of a cell and then somehow move the contents of the virus (i guess the viral DNA) into the host cell. If that is correct, it would take some energy to effect this injection -- I would guess that the virus is "spring loaded" -- there is no actual engine or need to generate energy as a human cell does. But if it is indeed sort of a spring, then two questions: how it the spring released and then how did the tension in the spring get created initially? [link] [comments]  |
| Is anesthesia medication universal for animals and humans? Posted: 24 Sep 2021 06:36 AM PDT There was a video of a Macaw waking up from anesthesia and I'm curious if the medication is universal. Do humans an animals use the same anesthetic medications? Are they derived from the same compounds? EDIT: Thank you everyone. This is very interesting to read through. 🤯 It's amazing how far we've come. [link] [comments]  |
| Posted: 24 Sep 2021 02:01 PM PDT Hello AskScience community! I am an ordinary consumer who recently took notice of the truly staggering improvements seen in the field of wireless data networking over the past 2 decades. Simply put, when I effortlessly play high quality YouTube videos on my phone with no issues, it truly feels like the engineering community is practicing black magic. I'd like to learn about how the RF engineering discipline was able to accomplish these improvements in a bit more technical detail. With that in mind, my question is as follows: what specific engineering improvements (signal processing techniques, electronic hardware on the user terminal side or the RAN/base-station, backhaul, or core network ) allowed for LTE to have higher download speeds than comparable "3G" technologies, such as CDMA2000 and HSPA? I've tried to keep this question as specific as possible, but I do want to note that the same question could be posed of the various "3G' technologies relative to their "2G" predecessors (GSM, CDMA) and that what I'm interesting in understanding is the full evolution of mobile technologies in at least a non-cursory level of detail. Resources would be welcomed! Additionally, a sub-question that is of particular interest to me is about the interplay between hardware and signal processing techniques in generating improvements in data rates that I am asking about. Specifically, one of the key reasons that I have seen noted for the increase in data throughput in moving from 3G technologies to "4G" technologies is simply moving the channel to higher frequencies, where there is more bandwidth to play with. But this raises the question - why didn't the (very smart) engineers who were designing 3G technologies like CDMA2000 and HSPA design those technologies to work at the same higher frequencies? It could of course be that operating at those frequencies was not possible until new techniques - which weren't conceived of prior to the ~2005-07 period when LTE hit its stride in development - were developed. But I suspect that at least part of the reason has to do with the fact that electronics improved in some fashion to allow cost-feasible construction of RF circuits that can operate at such frequencies. But perhaps I am wrong! Would greatly appreciate (relatively) technical answers to either the broader question of why LTE is faster than comparable 3G technologies and/or the more specific one about improvements in electronics! [link] [comments]  |
| How can we be sure that radiocarbon dating is accurate? Posted: 24 Sep 2021 11:00 AM PDT I recently read this article: It talks about how radiocarbon dating works and why our burning of fossil fuels is sort of throwing a wrench in the process. Which got me thinking, how can we be sure that it was accurate in the first place? To be sure I'm understanding the process correctly, let me give my rudimentary concept of it. So, the ratio of carbon-14 to carbon-12 isotopes in the environment is pretty stable. The whole time a plant or animal is alive, it's taking in carbon-14 and carbon-12 through breathing, eating, photosynthesis, etc. After the living thing dies, it stops taking in carbon. So the carbon-14, being more reactive starts to break down at a known rate, while the carbon-12 remains. We can look at the ratio of the two isotopes to get an idea of how long a living thing has been dead. Correct? The problem this article points out is that by burning fossil fuels (which were once those living things), we are releasing tons more carbon-12 into the environment than was there previously, messing up the starting ratio. My question is: why are we so sure about the ratio of carbon-14 to carbon-12 in the environment in ancient times? Is it possible that compared to 10,000 or a million years ago, there is already far more carbon-12 in the environment? Is it possible that when the earth was a baby planet, the environment was made up of almost entirely carbon-14? Would that screw up the estimates? Thanks! [link] [comments]  |
| Why noncompressible fluid has higher velocity when moving through smaller cross section area? Posted: 24 Sep 2021 09:16 AM PDT Mass flow rate states that cross section area is inversely proportional to fluid velocity in a closed pipe when fluid density is constant. Therefore, how did a body of fluid gain extra energy to increase its velocity when moving through a smaller cross section area? Did I miss something here? [link] [comments]  |
| How does the rapid covid test kit work? Posted: 24 Sep 2021 09:00 AM PDT From the look of it, I think it's paper chromatography? Also, what solution (or what kind of solution) is in the buffer? How can we explain the result that shows 1 line for the target (usually marked by "T") but doesn't show anything for the control ("C"), even though the buffer solution is already added to the sample? What about the result which shows no lines at all? Thanks for your input! [link] [comments]  |
| Are there other acidic pools like the ones in Yellowstone? Posted: 23 Sep 2021 07:26 PM PDT I read that someone dissolved in one of Yellowstone's acidic pools and it made me wonder if there are others in the world and what conditions cause them to exist? My searches only lead to articles about Yellowstone. [link] [comments]  |
| Dumb question: Do space vehicles have self destruct buttons? Posted: 23 Sep 2021 05:44 PM PDT We're watching Aliens. We suddenly realize the apparent absurdity of a self destruct system, yet it's a common trope in movies. Do space vehicles actually have self destruction processes? Thanks for wasting time with me [link] [comments]  |
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