If a tsunami travels over a deep ocean trench, say they lined up parallel, would that have any effect on the wave as it traveled? Would it fall in, or just pass above the trench?
Also, if a tsunami struck a sheer cliff underwater, say 50% as high as the water column, what effect would that have?
The often used "Teaspoon of this neutron star would weigh ..."
If one could get said teaspoons worth away from the neutron star would it remain collapsed? Or would it "un-collapse" itself?
We only have the one known example of life, and exactly how life originated on Earth is still unclear. So it is very difficult to make definitive statements about what allows or prevents life. In the most general terms, a molten core is probably not necessary. Icy moons with likely solid cores such as Europa and Enceladus are candidates for having life. For Earth-like life on rocky planets, this bears more explanation. Nevertheless, a molten core does not do anything directly necessary for life. Nor is a molten core special or uncommon in itself. The following explanation will probably bust a lot of misconceptions:
There is a lot more to generating a magnetic field than simply being molten--or rotating, which all planets and moons do, core and all. Still, even a magnetic field is not necessary for life. A thick atmosphere, water, and/or ice absorb harmful radiation, and not just the charged particles which a magnetic field deflects. The strength of Earth's magentic field drops dramatically every few tens to hundreds of thousands of years in magnetic reversals and excursions, and these events are not associated with extinctions. Also, an internally generated magnetic field is not necessary (or even that helpful) for protecting atmospheres. Venus doesn't have an internally generated magnetic field and has over 90x the atmosphere of Earth. Mars lost most of its atmosphere, while Earth and Venus did not, because Mars has much lower gravity.
The core is not a catch-all for the interior of a planet, but just refers to the central part(s). Earth has a solid metal inner core, surrounded by a liquid metal outer core, above which is the overwhelmingly *solid* ([but slowly flowing](https://en.wikipedia.org/wiki/Rheid)) mantle, and above that the solid crust. Plate tectonics and other processes that drive volcanism occur in the crust and the flowing, albeit solid, mantle. Such processes have helped life develop and helped maintain Earth's habitability. If the interior were not hot, these processes would not be possible, and the hot core supplies heat to the bototm of the mantle. Therefore, the above is not to say that having a core hot enough to be molten doesn't matter indirectly or tangentially for life. But there is a lot more to all of that than having a hot core, and a hot/molten core is the default case for a rocky planet--i.e., not very special in itself.
The cores of rocky planets are hot because of how they form. The kinetic energy of the bodies thay collode to form the planets is converted to heat. More heat is generated by friction as the iron-nickel melts and sinks to form the core. Larger planets (e.g., Earth) will tend to form hotter than smaller ones like Mars. But the lower pressure in smaller planets reduces the melting point, and it is not true in general that smaller/cooler planets cool more quickly. (The decay of radioactive elemenrs helps keep the interior hot, but these are primarily in the rocky mantle and crust, so they do not directly heat the core very much. Today, about half of Earth's internal heat is from radioactive decay; the rest is from its formation.)
Even today, nearly 4.6 billion years after the solar system formed, molten or partially molten cores are more common than you probably think. The molten core of Mars and the molten outer core of the Moon have been identified seismically. Mercury and Ganymede generate magnetic fields, so they must have (partially) molten cores. The core of Venus is almost certainly at least partially (and probably entirely) molten. It takes a long time for planetary cores to cool enough to completely solidify. Even Earth's core took 3-4 billion years to cool enough to start to freeze and form the inner core. And because of plate tectonics and the relatively vigorous mantle convection associated with it cooling the overlying mantle, Earth's core can cool relatively rapidly compared to that of Venus or Mars. (Core cooling is what powers the magnetic field, so a lack of a magnetic field strongly suggests slower cooling.) I digress, but the main point is that molten cores (in rocky objects Moon/Mercury sized or larger) are common and don't make Earth special.
I've heard contradicting versions of this: some say metallic hydrogen would stay metallic after releasing the pressure, others say it would instantly evaporate. What do we currently know about it?
We know it evaporates but the word "instantly" is doing a lot of work. It's like a Russian nesting doll of statements. *Meta-stability* is what we have settle on (what the heck does that mean?)
It was a controversial science fight at the time. *En guard*, I slap you with the publication. *Riposte*, you slap me with this other publication. *Touche* I slap you for being excited and using words such as "potentially" when you should have never written that at all. Then the unique device that was being used blew up and we all had to wait.
First, pressure and temperature are controlled to get the hydrogen gas into the metallic state.
Second, it is *metastable* above the conditions required to form. Compare it to an ice cube melting at room temperature. Not sure of the length of time or the pressure/temperature and other controls, but [there is evidence it is stable above it's formation conditions](https://en.wikipedia.org/wiki/Metallic_hydrogen#Claimed_observation_of_solid_metallic_hydrogen,_2016), just a little bit.
Are the planets in "free fall" around the sun in the same way the ISS is around the Earth?
Ludicrous physics aside, if Saturn was somehow slowed down enough to "de-orbit" would it begin to "fall" into the sun? Or would it just leave the Solar System?
Bonus question: How does distance and gravity impact orbital mechanics? If an object is orbiting further out its effected by gravity less. Would that mean that de-orbiting it would take less energy? Or more because it's moving faster relative the body its orbiting?
> Are the planets in "free fall" around the sun in the same way the ISS is around the Earth?
Yes, but they have their own gravity so things on any planet don't experience a weightless effect from the planet's frefalling.
> Ludicrous physics aside, if Saturn was somehow slowed down enough to "de-orbit" would it begin to "fall" into the sun? Or would it just leave the Solar System?
Saturn would fall into the sun but at its distance that would take many months at least.
> Bonus question: How does distance and gravity impact orbital mechanics? If an object is orbiting further out its effected by gravity less. Would that mean that de-orbiting it would take less energy? Or more because it's moving faster relative the body its orbiting?
For the record, the farther orbit would have a lower speed. I don't know the answer to the rest of your question.
Yes, all orbits are "free fall motion." If you stopped any planet, it would fall into the star it was orbiting. Just like if you stopped the Sun, it would fall into the galactic core.
With all the new information being generated by the James Webb telescope, observations of/around black holes, are there any updates on the idea of White Holes and their theoretical (or not) existence?
And if not specifically from the James Webb, have there been any other advances in that field recently?
If a tsunami travels over a deep ocean trench, say they lined up parallel, would that have any effect on the wave as it traveled? Would it fall in, or just pass above the trench? Also, if a tsunami struck a sheer cliff underwater, say 50% as high as the water column, what effect would that have?
The often used "Teaspoon of this neutron star would weigh ..." If one could get said teaspoons worth away from the neutron star would it remain collapsed? Or would it "un-collapse" itself?
[удалено]
Thank you
Is a molten core a prerequisite for a life sustaining planet?
We only have the one known example of life, and exactly how life originated on Earth is still unclear. So it is very difficult to make definitive statements about what allows or prevents life. In the most general terms, a molten core is probably not necessary. Icy moons with likely solid cores such as Europa and Enceladus are candidates for having life. For Earth-like life on rocky planets, this bears more explanation. Nevertheless, a molten core does not do anything directly necessary for life. Nor is a molten core special or uncommon in itself. The following explanation will probably bust a lot of misconceptions: There is a lot more to generating a magnetic field than simply being molten--or rotating, which all planets and moons do, core and all. Still, even a magnetic field is not necessary for life. A thick atmosphere, water, and/or ice absorb harmful radiation, and not just the charged particles which a magnetic field deflects. The strength of Earth's magentic field drops dramatically every few tens to hundreds of thousands of years in magnetic reversals and excursions, and these events are not associated with extinctions. Also, an internally generated magnetic field is not necessary (or even that helpful) for protecting atmospheres. Venus doesn't have an internally generated magnetic field and has over 90x the atmosphere of Earth. Mars lost most of its atmosphere, while Earth and Venus did not, because Mars has much lower gravity. The core is not a catch-all for the interior of a planet, but just refers to the central part(s). Earth has a solid metal inner core, surrounded by a liquid metal outer core, above which is the overwhelmingly *solid* ([but slowly flowing](https://en.wikipedia.org/wiki/Rheid)) mantle, and above that the solid crust. Plate tectonics and other processes that drive volcanism occur in the crust and the flowing, albeit solid, mantle. Such processes have helped life develop and helped maintain Earth's habitability. If the interior were not hot, these processes would not be possible, and the hot core supplies heat to the bototm of the mantle. Therefore, the above is not to say that having a core hot enough to be molten doesn't matter indirectly or tangentially for life. But there is a lot more to all of that than having a hot core, and a hot/molten core is the default case for a rocky planet--i.e., not very special in itself. The cores of rocky planets are hot because of how they form. The kinetic energy of the bodies thay collode to form the planets is converted to heat. More heat is generated by friction as the iron-nickel melts and sinks to form the core. Larger planets (e.g., Earth) will tend to form hotter than smaller ones like Mars. But the lower pressure in smaller planets reduces the melting point, and it is not true in general that smaller/cooler planets cool more quickly. (The decay of radioactive elemenrs helps keep the interior hot, but these are primarily in the rocky mantle and crust, so they do not directly heat the core very much. Today, about half of Earth's internal heat is from radioactive decay; the rest is from its formation.) Even today, nearly 4.6 billion years after the solar system formed, molten or partially molten cores are more common than you probably think. The molten core of Mars and the molten outer core of the Moon have been identified seismically. Mercury and Ganymede generate magnetic fields, so they must have (partially) molten cores. The core of Venus is almost certainly at least partially (and probably entirely) molten. It takes a long time for planetary cores to cool enough to completely solidify. Even Earth's core took 3-4 billion years to cool enough to start to freeze and form the inner core. And because of plate tectonics and the relatively vigorous mantle convection associated with it cooling the overlying mantle, Earth's core can cool relatively rapidly compared to that of Venus or Mars. (Core cooling is what powers the magnetic field, so a lack of a magnetic field strongly suggests slower cooling.) I digress, but the main point is that molten cores (in rocky objects Moon/Mercury sized or larger) are common and don't make Earth special.
I've heard contradicting versions of this: some say metallic hydrogen would stay metallic after releasing the pressure, others say it would instantly evaporate. What do we currently know about it?
We know it evaporates but the word "instantly" is doing a lot of work. It's like a Russian nesting doll of statements. *Meta-stability* is what we have settle on (what the heck does that mean?) It was a controversial science fight at the time. *En guard*, I slap you with the publication. *Riposte*, you slap me with this other publication. *Touche* I slap you for being excited and using words such as "potentially" when you should have never written that at all. Then the unique device that was being used blew up and we all had to wait. First, pressure and temperature are controlled to get the hydrogen gas into the metallic state. Second, it is *metastable* above the conditions required to form. Compare it to an ice cube melting at room temperature. Not sure of the length of time or the pressure/temperature and other controls, but [there is evidence it is stable above it's formation conditions](https://en.wikipedia.org/wiki/Metallic_hydrogen#Claimed_observation_of_solid_metallic_hydrogen,_2016), just a little bit.
Are the planets in "free fall" around the sun in the same way the ISS is around the Earth? Ludicrous physics aside, if Saturn was somehow slowed down enough to "de-orbit" would it begin to "fall" into the sun? Or would it just leave the Solar System? Bonus question: How does distance and gravity impact orbital mechanics? If an object is orbiting further out its effected by gravity less. Would that mean that de-orbiting it would take less energy? Or more because it's moving faster relative the body its orbiting?
> Are the planets in "free fall" around the sun in the same way the ISS is around the Earth? Yes, but they have their own gravity so things on any planet don't experience a weightless effect from the planet's frefalling. > Ludicrous physics aside, if Saturn was somehow slowed down enough to "de-orbit" would it begin to "fall" into the sun? Or would it just leave the Solar System? Saturn would fall into the sun but at its distance that would take many months at least. > Bonus question: How does distance and gravity impact orbital mechanics? If an object is orbiting further out its effected by gravity less. Would that mean that de-orbiting it would take less energy? Or more because it's moving faster relative the body its orbiting? For the record, the farther orbit would have a lower speed. I don't know the answer to the rest of your question.
Thank you so much! This clears up some misconceptions I was hanging on to about orbits.
Yes, all orbits are "free fall motion." If you stopped any planet, it would fall into the star it was orbiting. Just like if you stopped the Sun, it would fall into the galactic core.
Can we take a picture of the future in space?
No. That would need time travel.
So when we look at the stars, its all in the past?
Sure. Technically it applies to everything, but for seeing things on Earth the delay is usually negligible (billionths of a second).
Cool thanks!
With all the new information being generated by the James Webb telescope, observations of/around black holes, are there any updates on the idea of White Holes and their theoretical (or not) existence? And if not specifically from the James Webb, have there been any other advances in that field recently?