Score
Title
442
AskScience Panel of Scientists XVII
734
Is there a limit on how long a power cord can be?
1364
I know it takes two weeks for the flu vaccine to be fully effective. I assume effectiveness is zero right before the vaccine is administered, and maximum after two weeks. But is there a graph that shows how effectiveness changes in time?
8642
Why is the Congo River so deep?
16
Why the Antarctic ice cap stays in one place and does not drift freely like an iceberg?
45
Why is the separation constant for the radial equation of the Hydrogen atom in the form of L(L+1)?
11
Why can some viruses (smallpox, polio) be virtually eradicated while others cannot (HIV, influenza)?
18
If the capacity of a battery charging another battery drops below that of the receiving battery, will it stop transferring electricity since the electrons will no longer prefer to leave the lower energy "state" of the drained battery?
2
How does a coax splitter work?
10
If our bodies are conductive, can holding a battery between two fingers deplete it completely?
36
How/why are so many mathematical proofs and theorems contingent on the Riemann hypothesis being true?
2
Is there a link between a metal being conductive from an electric standpoint and it being magnetic? If so, what is the cause?
7440
Are there any predators that hunt for sport rather than for food?
24
Do they update the voyager software?
2
How did the Russian Woodpecker receiver work?
3
Are there any ant species that don’t live in colonies?
2
What is meant by the heat death of the universe?
21
Does language affect learning and studying?
2
If the strength of an acid is based on concentration, why are acids like Sulfuric Acid always considered so dangerous compared to others?
27
When water does down the drain, why does it always go down the drain in a form of whirlpool.?
13
From what I have learnt so far, refrigerators use chlorofluorocarbons for cooling. Do these chlorofluorocarbons run out after some time? If yes how are they replenished?
1
Microwave Ovens and Wi-Fi Signals Operate at The Same Frequency (2.4GHz). What Makes Microwave Ovens More Dangerous?
19
What makes things transparent?
18
What allows certain cars and airplanes to have their own Wifi?
35
What causes the thick mist/fog that I frequently see coming off of mountains in my area?
10
What exactly happens to a person's behavior after a lobotomy?
8
How Bayes rule was used to help with aiming cannons?
7
Is there a limit to the energy density of batteries?
0
What kind of waves on the Electromagnetic Spectrum do metal detectors use to isolate only metal and no other materials?
2
Is a Colliod a state of matter?
5
How do particle accelerators such as the LHC detect particle collision products?
20
Many poisonous and venomous vertebrates get their toxins from toxic arthropods that form part of their diets. Why can't they just form the toxins themselves the same ways their prey do?
195
Why are hail storms so short?
6
How do marine mammals keep their testes cool?
68
If aliens were to look at earth through a telescope from 65 million lightyears away, would they see dinosaurs?
13
Why does fire flicker?
32
What exactly is string theory and how does it work?
10736
What exactly does the cold virus do to me to make me so weak?
4
I understand conduction and radiation as modes of heat transfer, but convection confuses me. Why does fluid moving over an object remove heat from it as opposed to adding heat due to friction?
12
Are initial telomere lengths fairly consistent in mammals? Barring external circumstances, do they decay at the same rate?
2
Is it possible light has a mass?
16 EricHunting The ISS is hit by very small debris occasionally and has had near-misses by larger debris. Things in orbital space don't move around at random but on consistent paths. Most of these paths are not perfectly stable, being affected by the varying gravity of the Earth, the light drag of gasses in the stratosphere, and the forces of solar wind and even the pressure of light, and so their orbits can 'decay' over time, causing them to fall into the Earth after some period of time. Active satellites maintain or change these paths with periodic boosts by small on-board rockets or thrusters. The paths of most large objects in space are recorded and continuously tracked so that their possible locations at any time in the future can be predicted, allowing collisions to be avoided. But very small objects cannot be easily detected by radar or telescopes and so are much harder to predict. So manned spacecraft are usually armored for protection against being hit by these small objects. With the number of things in orbit today very large, there is a potential hazard called the Kessler Syndrome. This is when a collision between two things in orbit produce a lot of small debris that fly off in many directions and can't be tracked, colliding into other things producing even more debris, and so on. If this was severe enough, it could destroy most satellites and create a vast swarm of debris preventing manned spacecraft from safely travelling to space for decades or centuries, until all these small objects were finally swept out of orbit naturally or deliberately cleared by other means we haven't yet developed. This is what makes the militarization of space very dangerous for our future in space. You can't use or even test weapons in space without the risk of causing one of these Kessler events.
2 katinla Whenever there is a risk that the ISS may come closer than 5 km to another satellite or a catalogued debris, they perform a collision avoidance manoeuvre. This can only work for objects that are larger than a few cm across so they can be tracked. Smaller objects are handled by MMOD shields. Post-flight inspection of the MPLM modules has revealed that the ISS has been hit several times, but the shields were strong enough to resist. These modules weren't shielded very heavily anyway because they weren't expected to stay in orbit for long time - other modules and especially those at the front of the station (Columbus, Kibo) are shielded much more paranoidly. This NASA document is quite detailed: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20060026214.pdf
1 Lazrath First off real satellites are at much higher altitudes, nowhere near the ISS The ISS is at such a low altitude that there is still some atmosphere, so most things "junk"(and other micro-satellites) would eventually decay and fall back to earth. The ISS re-boosts itself every month or so, to stay in orbit source graph; http://www.heavens-above.com/IssHeight.aspx
16 0 EricHunting The ISS is hit by very small debris occasionally and has had near-misses by larger debris. Things in orbital space don't move around at random but on consistent paths. Most of these paths are not perfectly stable, being affected by the varying gravity of the Earth, the light drag of gasses in the stratosphere, and the forces of solar wind and even the pressure of light, and so their orbits can 'decay' over time, causing them to fall into the Earth after some period of time. Active satellites maintain or change these paths with periodic boosts by small on-board rockets or thrusters. The paths of most large objects in space are recorded and continuously tracked so that their possible locations at any time in the future can be predicted, allowing collisions to be avoided. But very small objects cannot be easily detected by radar or telescopes and so are much harder to predict. So manned spacecraft are usually armored for protection against being hit by these small objects. With the number of things in orbit today very large, there is a potential hazard called the Kessler Syndrome. This is when a collision between two things in orbit produce a lot of small debris that fly off in many directions and can't be tracked, colliding into other things producing even more debris, and so on. If this was severe enough, it could destroy most satellites and create a vast swarm of debris preventing manned spacecraft from safely travelling to space for decades or centuries, until all these small objects were finally swept out of orbit naturally or deliberately cleared by other means we haven't yet developed. This is what makes the militarization of space very dangerous for our future in space. You can't use or even test weapons in space without the risk of causing one of these Kessler events.
2 0 tminus7700 They can actually move the station, depending on the prediction of a orbit of an object that might collide with the station. https://sma.nasa.gov/news/articles/newsitem/2015/11/23/two-more-collision-avoidance-maneuvers-for-the-international-space-station https://orbitaldebris.jsc.nasa.gov/quarterly-news/pdfs/odqnv16i2.pdf
2 0 katinla Whenever there is a risk that the ISS may come closer than 5 km to another satellite or a catalogued debris, they perform a collision avoidance manoeuvre. This can only work for objects that are larger than a few cm across so they can be tracked. Smaller objects are handled by MMOD shields. Post-flight inspection of the MPLM modules has revealed that the ISS has been hit several times, but the shields were strong enough to resist. These modules weren't shielded very heavily anyway because they weren't expected to stay in orbit for long time - other modules and especially those at the front of the station (Columbus, Kibo) are shielded much more paranoidly. This NASA document is quite detailed: https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20060026214.pdf
1 0 Lazrath First off real satellites are at much higher altitudes, nowhere near the ISS The ISS is at such a low altitude that there is still some atmosphere, so most things "junk"(and other micro-satellites) would eventually decay and fall back to earth. The ISS re-boosts itself every month or so, to stay in orbit source graph; http://www.heavens-above.com/IssHeight.aspx