The thread for space cadets!

Timsup2nothin said:
He actually said "80,000 Hiroshimas." 80,000 megatons is at least a decent pop. I went back to the calculator and fooled around until I got a 60,000 megaton result and I was getting a sunburn from the fireball at 250km with window shattering air blast and 7.8 earthquake. But the 'size of Texas' global killer from the movie didn't have to fool around with nuclear winter, it would be just an instant scorcher and that would be that.

Fortunately it was well into the "hasn't happened since Earth's initial accumulation, ain't gonna" class. The planet has gotten old and stodgy. It's just no fun any more.
Click to expand...
I meant 80,000 Hiroshimas, sorry.
 
Well that's cool. A Hiroshima style nuke in city hall of the next city down the road would have minimal impact in my city. Even the fallout would spread the other way.
 
That would depend on wind I believe. You can adjust it somewhere.

A typical 800kt Russian warhead detonating over Rota base would barely affect my home which is about 20 km South. Fallout wouldn't touch me either since the dominant winds at the zone are usually from west or south-east, rarely from North. So I laugh at WW3. :rockon:
 
but the whole point is that . While a very big majority would have no need for calculations , it's 2134 or 5 and Bruce Willis will still be alive or whatever and there is NOTHING to fear ...

and why , Russians can't hit elephants when tied and straight from one former Secretary of Navy , Lehman by the name , Americans would fire 600 on Moscow , so , well ....
 
https://phys.org/news/2019-02-earth-solid-surface-life-inclined-climate.html

"Earth's solid surface and moderate climate may be due, in part, to a massive star in the birth environment of the Sun, according to new computer simulations of planet formation.

Without the star's radioactive elements injected into the early solar system, our home planet could be a hostile ocean world covered in global ice sheets.

Right when the proto-Sun formed, a supernova occurred in the cosmic neighborhood. Radioactive elements, including aluminium-26, were fused in this dying massive star and got injected into our young solar system, either from its excessive stellar winds or via the supernova ejecta after the explosion."

So a nearby supernova around the time our sun was born - possibly the same one that triggered the collapse of our nebula 4.6+ bya to form our system - dumped its radioactive material into the solar system after the sun began fusing hydrogen into helium. Without this infusion of hot material planet Earth might have been - remained - covered by a very deep ocean.

"All planets have a core, mantle (inside layer) and crust. If the water content of a rocky planet is significantly greater than on Earth, the mantle is covered by a deep, global ocean and an impenetrable layer of ice on the ocean floor. This prevents geochemical processes, such as the carbon cycle on Earth, that stabilize the climate and create surface conditions conducive to life as we know it."

And life could not take off until those heavy elements became incorporated into the Earth's crust and upper mantle. The late heavy bombardment enabled both plate tectonics and life to develop. The shock wave from that supernova gave birth to our sun and then material from the blast reached the solar system later, around 4-4.1 bya.

Now the earth was formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters.

Spirit can be translated as 'wind(s)'
 
The Earth is not strongly disturbed by the impact and loses negligible mass.
The impact does not make a noticeable change in the tilt of Earth's axis (< 5 hundredths of a degree).
Depending on the direction and location of impact, the collision may cause a change in the length of the day of up to 35.7 minutes.
The impact does not shift the Earth's orbit noticeably.
Click to expand...

I noticed that even a rock the size of Texas has only negligible "major global changes."

I scaled up the impactor to be the size and density of Mars and got the following:

The Earth is strongly disturbed by the impact, but loses little mass.
Depending on the direction and location the collision, the impact may make a very small change in the tilt of Earth's axis (< half a degree).
Depending on the direction and location of impact, the collision may cause a change in the length of the day of up to 120 hours.
The impact does not shift the Earth's orbit noticeably.
Click to expand...
 
Berzerker said:
https://phys.org/news/2019-02-earth-solid-surface-life-inclined-climate.html

"Earth's solid surface and moderate climate may be due, in part, to a massive star in the birth environment of the Sun, according to new computer simulations of planet formation.

Without the star's radioactive elements injected into the early solar system, our home planet could be a hostile ocean world covered in global ice sheets.

Right when the proto-Sun formed, a supernova occurred in the cosmic neighborhood. Radioactive elements, including aluminium-26, were fused in this dying massive star and got injected into our young solar system, either from its excessive stellar winds or via the supernova ejecta after the explosion."

So a nearby supernova around the time our sun was born - possibly the same one that triggered the collapse of our nebula 4.6+ bya to form our system - dumped its radioactive material into the solar system after the sun began fusing hydrogen into helium. Without this infusion of hot material planet Earth might have been - remained - covered by a very deep ocean.

"All planets have a core, mantle (inside layer) and crust. If the water content of a rocky planet is significantly greater than on Earth, the mantle is covered by a deep, global ocean and an impenetrable layer of ice on the ocean floor. This prevents geochemical processes, such as the carbon cycle on Earth, that stabilize the climate and create surface conditions conducive to life as we know it."

And life could not take off until those heavy elements became incorporated into the Earth's crust and upper mantle. The late heavy bombardment enabled both plate tectonics and life to develop. The shock wave from that supernova gave birth to our sun and then material from the blast reached the solar system later, around 4-4.1 bya.

Now the earth was formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters.

Spirit can be translated as 'wind(s)'
Click to expand...
Wait, a layer of ice on the ocean floor?

One of the main features of water is it is denser liquid than solid, in contrast with ammonia and most other substances. So there cannot be a liquid water ocean with any ice at the bottom because ice floats.
 
Thorgalaeg said:
Wait, a layer of ice on the ocean floor?

One of the main features of water is it is denser liquid than solid, in contrast with ammonia and most other substances. So there cannot be a liquid water ocean with any ice at the bottom because ice floats.
Click to expand...

I saw that and wondered how that could work. The only thing I can think of is some way of anchoring the ice to the bottom, like how Antarctica anchors ice below sea level. If sea levels rose 2 miles would all that ice simply lift off the continent and float? I dont know.
 
Another possibility is impurities. If a glacier picks up a whole lot of rocks as it progresses, then calves off an iceberg with a high net density because it contains all that rock, the iceberg could sink.
 
Under high enough pressures ice can become more dense than water. I'd guess that's what's driving the effect in the simulation given we're talking about a much larger ocean than actually exists, with correspondingly higher pressure at the bottom.
 
They might also not be talking about pure ice, but ammonia-rich ice in an ocean that is also not purely water. In that case, the densities might turn out in a way that the ice doesn't float.
 
Lexicus said:
Under high enough pressures ice can become more dense than water. I'd guess that's what's driving the effect in the simulation given we're talking about a much larger ocean than actually exists, with correspondingly higher pressure at the bottom.
Click to expand...
Yep. Ice formed at very high pressure has a different cristaline structure and it is more dense than liquid water at said high pressure. About 3000 atmospheres are needed to go from normal ice to ice II (which is rhombohedral instead of hexagonal) according Wikipedia. That means a 30,000 meters depth ocean, three times the Marianas trench. That is a lot of water. Adding a bit of ammonia as uppi said could help too.

This remembers me some SF novels by Hal Clement.
 
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Lexicus said:
Bah. Negligible compared to this stuff:
https://qntm.org/destroy
Click to expand...

ı don't even bother to read texts that fail to mention the Death Star , when it comes to destroying planets . And yeah , there is even a preview or whatever of Episode VII ; which might be a reason why the blog owner closed the option down ...
 
r16 said:
ı don't even bother to read texts that fail to mention the Death Star , when it comes to destroying planets .
Click to expand...
You didn't read far enough: that's in the 'fictitious planet-killers' section/link ;)
 
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