Score
Title
90
AskScience Panel of Scientists XVIII
1882
What’s the largest star system in number of planets?
3807
What is the effect, positive or negative, of receiving multiple immunizations at the same time; such as when the military goes through "shot lines" to receive all deployment related vaccines?
514
AskScience AMA Series: I am Melinda Krahenbuhl and I am the director of the Reed Research Reactor, the only nuclear reactor operated primarily by undergraduate students. AMA!
13
How does the cosmic microwave background persist? Why hasn't it been distorted and destroyed by new sources of energy pumping into space?
7
Can you use a normal (CMOS) camera for detecting scintillation?
46
How can brain cells cause tumours even though they can not multiply?
1575
Ask Anything Wednesday - Biology, Chemistry, Neuroscience, Medicine, Psychology
1125
What triggers beta particles to form, and for what reason can they not penetrate substantially thick aluminium?
3
What is the nonrenewable fuel cost to produce x quantity of electricity?
1238
If capacitance increases as distance between plates decreases, why aren't there very small 1F capacitors?
2
How applicable are Newtonian Physics in real life? Is it completely false or are there some concepts which can be used to accurately predict real-life situations?
1050
is it possible to move an object in circular motion using magnets?
3
How far back can you go before carbon dating becomes unreliable?
0
Why hasn't The Asteroid Belt formed a planet?
61
Do wild animals get physical addictions to substances?
7
Is there any evidence to suggest that biracial people are less susceptible to genetic diseases?
15
Is there any evidence that pornography is a public health risk?
3
What would hydrogen in metal form look like?
8
How fast does a sun blow up? Not as in life span, but say a supernova, how long would it take for the process to complete?
19
What causes the increased grip on paper when you lick your finger?
13
Would someone who got into an accident that put them into a coma for a couple of weeks still be addicted to a drug that they were addicted to prior to the accident? Why or why not?
2
Why are mercury salts a common first choice for heavy atom soaks in protein crystallography?
3
Why do you loose the coefficient when you differentiate ln(2x) and then integrate it to ln(x)?
3
Why does sleep deprivation and lack of sleep increase depression?
4
Can the effect of a "bunker buster" be accurately predicted, in relation to the target's compressive strength?
0
What are the basic units of measurement, IE time, distance, mass etc, that can be used to derive every other unit, such as joules, power, or magnetic force?
37153
Why is it that during winter it's not uncommon to have days with abnormally high temperature and summer-like weather, but in the summer it never drops to winter-like weather for a day?
34
How does Positron Emission Topography (PET) work?
3
What kind of sound do the stars make?
103
What happens to the spin of an electron when it leaves a nucleus?
2
Do genetics influence the way one's voice sounds?
2
Can someone explain my questions about the orbits of the James Webb Space Telescope?
8
How can we hear when someone is smiling?
9
What happens if a natural gas deposit in the ground ignites?
5
Is there anything that can bond to TRPV1 receptors that would completely or relatively dull capsaicin before ingesting it?
10
Do you burn the same number of calories during a given activity when you're fit as when you're unfit?
11
How does the Hubble Telescope take pictures?
1
How are defining mutations in haplogroups chosen?
4
What about the properties of bronze makes it good for musical instruments and bells?
1
How many cell layers thick is the human epidermis?
17 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
2 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
2 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