Score
Title
378
AskScience Panel of Scientists XVII
78237
Help us fight for net neutrality!
11142
From my kid: Can you put a marshmallow on a stick out into space and roast it with the sun?
16
What would our world look like if the collision which ejected the material from which formed the Moon had not occurred? Would there be liquid water? What kind of atmosphere if any? Active geological processes? Life?
4
[physics] When I turn off my oven but leave the door closed how does the temperature cool?
3
How accurate is the usual picture of the atomic nucleus of a ball/mass of protons and neutrons? What's really happening in the centre of atoms?
42
On my bike: is it more efficient to pedal fast in a low gear or slower in a high gear?
3
How would the government broadcast an emergency message in today's world where a majority of people watch tv through a streaming service?
1
If the Earth is closer to the sun for a part of the year, why isn't that summer MUCH hotter?
1
How do you define the number of conduction electrons?
10
What makes it "impossible" as of now to detect the hypothetical Graviton particle?
9
How are Muscle Knots / Trigger Points Created at the Cellular Level?
2
Can Dark Matter be explained by scale Invariance of empty space?
17
Is deep-earth nuclear fission heating the Earth's interior?
4
How in the world could a particle have a 1/2 spin value?
3371
Hein et al (2017) have explored scenarios for sending a spacecraft to the recently confirmed interstellar asteroid "Oumuamua". What payloads and capabilities would we wish to prioritize on the exploration of this strange and peculiar object?
11
How are doctors able to determine genetic abnormality in a fetus, by testing the mother’s blood?
11
Are all prime numbers smaller than the biggest prime number discovered?
10
What exactly is the Van Allen radiation belt?
6
Why children with adenoditis fall behind in their neurophychiatric development and do they recover in that aspect after the inflammation is gone?
12
Can blue light cause cancer? What about UVA? Where is the threshold?
4
When there is a momentum transfer between two charged particles (via a virtual particle) is that transfer instantaneous?
10
Do cephalopods control their camouflage consciously, if yes how exactly can an animals thought's change it's cells?
15
How does restricting Internet work?
11
Why can't powerbanks charge while being charged?
9
Is it a coincidence that the moons rotation around its axis matches the duration for its revolution around the earth? Or is there some scientific explanation on how these aligned in such a fashion?
7
Ask Anything Wednesday - Engineering, Mathematics, Computer Science
2
Are there any advantages to Removing Net Neutrality that the consumer can enjoy and not ISPs?
4
How does your body heal cuts?
6
How do they know 'Oumuamua is elongated vs of assymetric albedo? (Bonus Question: Is the assumed rotation stable?)
1
What changes when you break the sound barrier?
10
How, or why, do refraction and dispersion occur?
2
Are electrostatic interactions photon-mediated?
2
How does Lebesgue integral put Riemann integral and discrete sums in the same theorical mold ?
25
Why are radio waves and microwaves more damaging to the human body than light waves?
14
In my Psychology textbook it says that cortisol (a result of stress) reduces telomerase activity, therefore speeding up the aging process, however, I know that exercise also releases cortisol, yet is known to combat aging - how?
2
I measured an imaginary component of Earth's magnetic field?
3
Why does water behave like a mirror?
6
Why don't electrons in a superconductor radiate away their energy?
1
Why does the index of refraction of water change with temperature?
14
Why do planets orbit in planes?
4 Gargatua13013 We often get that kind of question, so have a look at the kind of data we have to work with. Mountain chains are highly dynamic environments which form in collision zones between 2 plates. Rocks from different initial depths are rearranged and [thrust/folded into different configurations](ftp://131.215.65.7/pub/avouac/Ge277-2010/Davis1983.pdf). At some point the process stops and you reach "peak mountain building" ... The mountain chain is at its tallest, and it all downhill from there (sorry). If you had a time machine you could actually go and measure the maximum altitude reached. But we can't and we don't. By the time we get to looking into those matters, time has passed and erosion taken large parts of the mountain chain away. So, what we actually do is look at the chemistry of the minerals which make up the metamorphic rocks formed under that mountain chain. As rocks of a given composition are brought to different pressure (P) and temperature (T) conditions, they undergo chemical reactions and re-equilibrate to different mineral assemblages. Some of these assemblages are particularly sensitive to temperature and pressure and act as [geothermobarometers](https://en.wikipedia.org/wiki/Geothermobarometry). They may rely on the ratios of trace elements incorporated in a specific mineral, or on isotopic ratios. Garnets and amphiboles are particularly well suited for these kind of studies, and allow the calculation of [P-T paths](https://www.researchgate.net/profile/Jane_Selverstone/publication/220021207_P-T_paths_from_garnet_zoning_A_new_technique_for_deciphering_tectonic_processes_in_crystalline_terranes/links/5489e1140cf214269f1abe5b/P-T-paths-from-garnet-zoning-A-new-technique-for-deciphering-tectonic-processes-in-crystalline-terranes.pdf), a historical trajectory through Temperature-Pressure space through which a given rock has passed. Add to that the possibility of using amphiboles or other minerals as geochonometers and you can calibrate those paths into the time (t) dimension, generating a P-T-t path. This allows you then to determine how much pressure that rock was under at a given time. But (and it's a huge but), translating that data into mountain altitude is not an easy thing. You have to make assumptions about heat flow, because geothermobarometers are temperature-dependant. There is a marging of error on the initial measurements, and they add up. So in the end you wind up with a range of possible heights, which seldom satisfies whomever asked the initial question. I hope this clears things up.
6 0 Gargatua13013 We often get that kind of question, so have a look at the kind of data we have to work with. Mountain chains are highly dynamic environments which form in collision zones between 2 plates. Rocks from different initial depths are rearranged and [thrust/folded into different configurations](ftp://131.215.65.7/pub/avouac/Ge277-2010/Davis1983.pdf). At some point the process stops and you reach "peak mountain building" ... The mountain chain is at its tallest, and it all downhill from there (sorry). If you had a time machine you could actually go and measure the maximum altitude reached. But we can't and we don't. By the time we get to looking into those matters, time has passed and erosion taken large parts of the mountain chain away. So, what we actually do is look at the chemistry of the minerals which make up the metamorphic rocks formed under that mountain chain. As rocks of a given composition are brought to different pressure (P) and temperature (T) conditions, they undergo chemical reactions and re-equilibrate to different mineral assemblages. Some of these assemblages are particularly sensitive to temperature and pressure and act as [geothermobarometers](https://en.wikipedia.org/wiki/Geothermobarometry). They may rely on the ratios of trace elements incorporated in a specific mineral, or on isotopic ratios. Garnets and amphiboles are particularly well suited for these kind of studies, and allow the calculation of [P-T paths](https://www.researchgate.net/profile/Jane_Selverstone/publication/220021207_P-T_paths_from_garnet_zoning_A_new_technique_for_deciphering_tectonic_processes_in_crystalline_terranes/links/5489e1140cf214269f1abe5b/P-T-paths-from-garnet-zoning-A-new-technique-for-deciphering-tectonic-processes-in-crystalline-terranes.pdf), a historical trajectory through Temperature-Pressure space through which a given rock has passed. Add to that the possibility of using amphiboles or other minerals as geochonometers and you can calibrate those paths into the time (t) dimension, generating a P-T-t path. This allows you then to determine how much pressure that rock was under at a given time. But (and it's a huge but), translating that data into mountain altitude is not an easy thing. You have to make assumptions about heat flow, because geothermobarometers are temperature-dependant. There is a marging of error on the initial measurements, and they add up. So in the end you wind up with a range of possible heights, which seldom satisfies whomever asked the initial question. I hope this clears things up.