Most of the energy the Earth receives is dissipated in the oceans. Very little is used to heat the interior. Back when the Moon was much closer to the Earth, the tidal heating on both bodies would have been more significant, but the Moon has receded so far away that it's not that important now.
The bulk of the Earth's (and Venus's) internal heating is the result of the decay of long-lived radioactive isotopes in the mantle (K, U, Th), and heat leftover from the accretion and differentiation processes. Assuming the solar nebula had similar compositions where Venus and Earth formed, then they ought to have similar amounts of radioactivity. Venus may have actually retained more of its accretionary heat, since it lacks plate recycling, which is a very efficient way for the Earth to cool. Less that 1% of the Earth's heat flow is from volcanoes. We don't actually know Venus's long-term tectonic regime. Currently it's lithospheric conduction, which is very inefficient. But the relatively young (~ 700 My) surface age suggests it must have resurfaced somehow.
As for TFA, I'm quite skeptical. Plate tectonics on Mars has indeed been investigated before. In the nineties, the hemispheric dichotomy was hypothesized to be a plate boundary. But the rest of the geological evidence was not convincing, and I don't think it ever gained much support. In the late nineties / early aughts, there were measurements of stripes of crustal magnetism in the southern highlands, a pattern similar to the magnetic reversals on Earth's seafloor. This brought up the idea of seafloor spreading, but the Martian stripes are much larger, and it's hard to see how this would occur in the thickest part of the crust.
The primary evidence for left lateral slip in TFA seems to be an offset impact crater. But I don't see it. The southern edge does look vaguely like an arc, but I see nothing on the northern side resembling a crater rim. The floor of the putative crater is the same depth as the rest of the Valles. I wouldn't expect that if this was actually an impact feature. I also don't see how lateral slip would result in such a wide rift. I think it's more likely this is actually a rift; extenison driven by loading of the lithosphere by Tharsis.
Further evidence presented is the linear arrangement of Arsia, Pavonis, and Ascraeus Montes. This has previously been suggested as evidence for hotspot volcanism. But here we have only three giant volcanoes instead of the dozens in the Hawaii-Emperor seamount chain. So if it's a plate moving over a hotspot, it's very puncutated. Moreover, the direction of motion would have to be perpendicular to that required for lateral movement along Valles Marineris. Furthermore, the linear pattern of the Tharsis Montes is only remarkable when you exclude the two large volcanoes that don't fall on that line: Alba Patera and Olympus Mons.
As someone who does computational geodynamics (mantle convection, tectonics, tidal dissipation), I use math(s) all the time. I'm doing trig, vector calculus, complex (real and imaginary) analysis, PDEs, and linear algebra all night and day. Sometimes I even bust out the spherical harmonics, why not? I don't use things like combinatorics, number theory, or topology, though the last is relevant for setting up meshes for finite element models. I don't use a lot of statistics, but my colleagues who perform more data analysis are all up in there.
The PDEs and the like are discretized for numerical integration, but I need to know the underlying continuous mathematics in order to do that. It's true that routines already exist for many standard problems, but if I want to add more physics or solve new problems, then I have to be able to do that myself. I also need to be able to solve simpler problems analytically, so that I can verify that the numerical models are actually giving the right answer.
I should note that my educational background is in the physical, rather than computational sciences (specifically geology, physics, and astronomy). This involved a lot of mathematics classes. A major in physics comes with a free minor in mathematics. My computer science background is relatively week. I've only ever taken a couple programming classes. I picked up most of my computing skills in grad school or on the job.
You can get a bit of that by watching old episodes of the Daily Show or the Weekend Update segments of old episodes of Saturday Night Live. In other news, Generalissimo Francisco Franco is still dead.
The masses given equate to 80000 kg and 23000 kg respectively. Or 80 and 23 (metric) tons. Two significant figures. Not more. No doubt those were the numbers originally supplied by the scientists, and the author of TFA converted it to pounds for the typical American reader without understanding how precision works. This happens all the time in the popular press. Clearly you can't estimate the weight of a creature you've never seen to within 1 lb. Your standard human's weight fluctuates by more than that over the course of a day.
Re:The 21st century formula for a successful compa
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I believe Futurama established that the correct pronoun is "shklee".
My original post was meant to be more a dig at the title than at anything else. Most watches are worn in the manner I described rather than with subdermal magnets.
The most common general term is "Planetary Geology". Most of my colleagues (IAAPS; PS="Planetary Scientist") don't usually use the planet-specific prefixes that often. It's much more common to say "Martian Geology" than to say "Areology", or "Lunar Geography" instead of "Selenography". I suppose that it's slightly inaccurate (given that "geo-" does technically mean "earth"), but it sounds much more natural to speak this way. There's also the problem that you'd need to modify each geo- term for each planetary body, and end up with "Enceladography" and "Iapetology". And what do we call the equipotential surface (geoid) on Vesta? "Vestoid" is already used for a class of asteroids.
In the US, dimes actually do say "ONE DIME". So if you don't already know that 1 dime = 10 cents, you can't tell from the coin. Obvious if you grew up with it, but I could easily imagine foreign visitors getting confused by that one.
So that would eliminate many active missions. MESSENGER, for example,left the ground over seven years ago and is doing fantastic science, but has been in Mercury orbit less than a year. Cassini is still doing all kinds of stuff at Saturn, but it launched fifteen years ago.
Technically, man IS an ape, if by "ape" you mean a member of Superfamily Hominoidea. Since chimpanzees are more closely related to humans than to anything else, any monophyletic clade must include humans. A clade of nonhuman apes would be paraphyletic.
no one had warned them about the ridiculous mortality rate for Starfleet members wearing red shirts!
I actually tracked this once and I seem to recall that there was no statistically significant correlation between shirt color and mortality (on TOS at least). Lack of a first and/or last name was a far more significant risk factor.
I'm pretty sure I started declining BEFORE I left school. I think my peak was in January 2003, immediately after having taken the comprehensive exam for my Ph.D. program. The exam was much more challenging than the dissertation and defense.
This kind of error in reporting is very common. The media will typically credit any discovery in astrophysics, planetary science, and related fields to "NASA" or "NASA scientists", regardless of who the actual discoverer is. Often the project is funded by a grant from NASA, but the science team are rarely employees of the agency.
Heh, heh, whoops! Thanks for the clarification. I didn't mean to suggest that the angular momentum of the entire Earth would be transferred to the spacecraft (though that would be interesting; one hell of a reaction wheel!), just their angular momentum vectors will point in the same direction.
That's a good point about the iron. There should be some, but at a far lower abundance than the silicates. Still, we're probably talking a few Earth masses of metal (real, actual metal, not what astrophysicists call metal).
I did notice that they speculated that the SiO2 should also dissolve, but I don't really know how valid that assumption is.
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Most of the energy the Earth receives is dissipated in the oceans. Very little is used to heat the interior. Back when the Moon was much closer to the Earth, the tidal heating on both bodies would have been more significant, but the Moon has receded so far away that it's not that important now.
The bulk of the Earth's (and Venus's) internal heating is the result of the decay of long-lived radioactive isotopes in the mantle (K, U, Th), and heat leftover from the accretion and differentiation processes. Assuming the solar nebula had similar compositions where Venus and Earth formed, then they ought to have similar amounts of radioactivity. Venus may have actually retained more of its accretionary heat, since it lacks plate recycling, which is a very efficient way for the Earth to cool. Less that 1% of the Earth's heat flow is from volcanoes. We don't actually know Venus's long-term tectonic regime. Currently it's lithospheric conduction, which is very inefficient. But the relatively young (~ 700 My) surface age suggests it must have resurfaced somehow.
As for TFA, I'm quite skeptical. Plate tectonics on Mars has indeed been investigated before. In the nineties, the hemispheric dichotomy was hypothesized to be a plate boundary. But the rest of the geological evidence was not convincing, and I don't think it ever gained much support. In the late nineties / early aughts, there were measurements of stripes of crustal magnetism in the southern highlands, a pattern similar to the magnetic reversals on Earth's seafloor. This brought up the idea of seafloor spreading, but the Martian stripes are much larger, and it's hard to see how this would occur in the thickest part of the crust.
The primary evidence for left lateral slip in TFA seems to be an offset impact crater. But I don't see it. The southern edge does look vaguely like an arc, but I see nothing on the northern side resembling a crater rim. The floor of the putative crater is the same depth as the rest of the Valles. I wouldn't expect that if this was actually an impact feature. I also don't see how lateral slip would result in such a wide rift. I think it's more likely this is actually a rift; extenison driven by loading of the lithosphere by Tharsis.
Further evidence presented is the linear arrangement of Arsia, Pavonis, and Ascraeus Montes. This has previously been suggested as evidence for hotspot volcanism. But here we have only three giant volcanoes instead of the dozens in the Hawaii-Emperor seamount chain. So if it's a plate moving over a hotspot, it's very puncutated. Moreover, the direction of motion would have to be perpendicular to that required for lateral movement along Valles Marineris. Furthermore, the linear pattern of the Tharsis Montes is only remarkable when you exclude the two large volcanoes that don't fall on that line: Alba Patera and Olympus Mons.
As someone who does computational geodynamics (mantle convection, tectonics, tidal dissipation), I use math(s) all the time. I'm doing trig, vector calculus, complex (real and imaginary) analysis, PDEs, and linear algebra all night and day. Sometimes I even bust out the spherical harmonics, why not? I don't use things like combinatorics, number theory, or topology, though the last is relevant for setting up meshes for finite element models. I don't use a lot of statistics, but my colleagues who perform more data analysis are all up in there.
The PDEs and the like are discretized for numerical integration, but I need to know the underlying continuous mathematics in order to do that. It's true that routines already exist for many standard problems, but if I want to add more physics or solve new problems, then I have to be able to do that myself. I also need to be able to solve simpler problems analytically, so that I can verify that the numerical models are actually giving the right answer.
I should note that my educational background is in the physical, rather than computational sciences (specifically geology, physics, and astronomy). This involved a lot of mathematics classes. A major in physics comes with a free minor in mathematics. My computer science background is relatively week. I've only ever taken a couple programming classes. I picked up most of my computing skills in grad school or on the job.
You can get a bit of that by watching old episodes of the Daily Show or the Weekend Update segments of old episodes of Saturday Night Live. In other news, Generalissimo Francisco Franco is still dead.
I don't think we're likely to have the occasional woolly mammoth of our ancestors. But I'll agree with the spirit of your suggestion.
I feel certain that nobody voted for Bill Clinton in 1994, as he had only been elected two years prior.
The masses given equate to 80000 kg and 23000 kg respectively. Or 80 and 23 (metric) tons. Two significant figures. Not more. No doubt those were the numbers originally supplied by the scientists, and the author of TFA converted it to pounds for the typical American reader without understanding how precision works. This happens all the time in the popular press. Clearly you can't estimate the weight of a creature you've never seen to within 1 lb. Your standard human's weight fluctuates by more than that over the course of a day.
I believe Futurama established that the correct pronoun is "shklee".
My original post was meant to be more a dig at the title than at anything else. Most watches are worn in the manner I described rather than with subdermal magnets.
A lesser person might have just attached the iPod to a wristband, and worn that. Like an _actual_ watch.
The most common general term is "Planetary Geology". Most of my colleagues (IAAPS; PS="Planetary Scientist") don't usually use the planet-specific prefixes that often. It's much more common to say "Martian Geology" than to say "Areology", or "Lunar Geography" instead of "Selenography". I suppose that it's slightly inaccurate (given that "geo-" does technically mean "earth"), but it sounds much more natural to speak this way. There's also the problem that you'd need to modify each geo- term for each planetary body, and end up with "Enceladography" and "Iapetology". And what do we call the equipotential surface (geoid) on Vesta? "Vestoid" is already used for a class of asteroids.
In the US, dimes actually do say "ONE DIME". So if you don't already know that 1 dime = 10 cents, you can't tell from the coin. Obvious if you grew up with it, but I could easily imagine foreign visitors getting confused by that one.
No. If someone makes a claim, that person needs to back it up.
So that would eliminate many active missions. MESSENGER, for example,left the ground over seven years ago and is doing fantastic science, but has been in Mercury orbit less than a year. Cassini is still doing all kinds of stuff at Saturn, but it launched fifteen years ago.
Technically, man IS an ape, if by "ape" you mean a member of Superfamily Hominoidea. Since chimpanzees are more closely related to humans than to anything else, any monophyletic clade must include humans. A clade of nonhuman apes would be paraphyletic.
But that would be socialism.
no one had warned them about the ridiculous mortality rate for Starfleet members wearing red shirts!
I actually tracked this once and I seem to recall that there was no statistically significant correlation between shirt color and mortality (on TOS at least). Lack of a first and/or last name was a far more significant risk factor.
Shred that stuff the moment it shows up. You don't want those documents getting into the wrong hands.
It's the only explanation that makes any sense at all.
Especially since the first commercially available Android phone was released less than two weeks before the 2008 election.
I'm pretty sure I started declining BEFORE I left school. I think my peak was in January 2003, immediately after having taken the comprehensive exam for my Ph.D. program. The exam was much more challenging than the dissertation and defense.
I feel certain that nobody at the south pole will be pushing anything out to sea, since it's over 1000 km away.
Yes, they're losing a day by effectively crossing the international dateline westward.
This kind of error in reporting is very common. The media will typically credit any discovery in astrophysics, planetary science, and related fields to "NASA" or "NASA scientists", regardless of who the actual discoverer is. Often the project is funded by a grant from NASA, but the science team are rarely employees of the agency.
Heh, heh, whoops! Thanks for the clarification. I didn't mean to suggest that the angular momentum of the entire Earth would be transferred to the spacecraft (though that would be interesting; one hell of a reaction wheel!), just their angular momentum vectors will point in the same direction.
That's a good point about the iron. There should be some, but at a far lower abundance than the silicates. Still, we're probably talking a few Earth masses of metal (real, actual metal, not what astrophysicists call metal).
I did notice that they speculated that the SiO2 should also dissolve, but I don't really know how valid that assumption is.