Score
Title
9418
Megathread: 2017 Hurricane Season
24
Earthquake Megathread
6172
If a nuclear bomb went off in Boston harbor could scientists tell after the fact who had manufactured it, do they leave distinct radioactive signatures?
5747
Why aren't there any orbitals after s, p, d and f?
16
What do sexes in fungus mean?
135
Do black holes have electromagnetic field?
4
Where does the "blast" portion of a nuclear explosion come from?
6
Do atmospheric CO2 measurements include a significant diurnal cycle?
8
How do bionic arms work?
4
Historically, when large numbers of sailboats/ships had to travel in formation as a fleet, are there different dynamics governing the movement of ships in the front, middle and rear of the group?
6
Why are non-differentiable continuous functions integrable?
9
Are Toucans (Americas) and Hornbills (Asia/Africa) an example of convergent evolution?
4
What are the estimated thicknesses for northern sea-ice at the height of the Pleistocene glaciation, and how are those thicknesses estimated?
7
Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science
2
Why are rainbows in an arc shape and does the radius change?
4
Why do nuclei release energy when they fuse?
24
How many layers are there in a modern integrated circuit?
8
Why does the Earth's rotation effect Rockets and not Planes?
2
Are there plant/animal somatic hybrids?
2
Would the opposite of codependency issues be considered as unhealthy as codependency? Wherein any form of dependency is abhorrent to the person in question? Does this have a clinical classification?
60
Do people that have degenerative diseases such as Alzheimer's lose their muscle memory as well?
20
How is it possible that something as large as a possible Planet 9 has completely evaded visual observation?
8154
There is a video on the Front Page about the Navy's Railgun being developed. What kind of energy, damage would these sort of rounds do?
8
Would global cooling create more land? If so, how much more land would be available before the whole earth freezes?
11
How did they measure hurricane wind speeds in the 1800's?
4125
In 1972 a woman fell 33,332 feet without dying. How is that possible?
12
How is it that scissors can curl ribbons?
12
What is happening at a molecular level when a knife cuts through nylon rope?
154
Could we railgun the Moon?
15
Why is caesium the largest atom? Shouldn't element 118 be the largest?
1
Why does your metabolism slow down with age?
7
Do snakes that can 'see' heat, such as ball pythons, compare their 'heat vision' with their normal vision?
17
[CHEMISTRY] How do chemical companies determine if one ingredient in a solution can be replaced by another?
2
In emergencies like on CDMX will using cellphone data on a very far state affect the capacity on CDMX cell towers to make calls and/or use cell phone data?
12
Can a human be allergic to any substance? As in, does every material have the potential to elicit an allergic response?
2
What defines an equation of state?
46
How is online gaming possible if there must be some delay?
5
Does my peripheral vision have a different latency than objects I look directly at?
15
Why is gold found in seams?
16
On an alien planet, would a regular compass still point true north?
11
Can someone with reading Aphasia "read" in Braille?
4
Would negative kelvin body always transfer heat to positive kelvin body?
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.