(I hope this is the correct location to put this...)

I am doing some research into various astronomical events, events that are, frankly, fascinating to write or read about, but stand a solid-form dihydrogen monoxide chance in a theological place of eternal torment of really occuring.

Honestly, I do not consider myself much of an astronomer (although I know more than the average off the streets... faint praise at that is). That is why I would like the assistance of others.

Enough introduction, allow me to present my first theoretical example.

I understand that a teaspoon of neutron material can mass as much as Earth. So, with that in mind, what would happen if just such an object was to strike Earth?

I don't consider this a typical "planet-killer" for several reasons. The first is that with a mass equal to Earth, the object puts out a considerable gravitational effect (no, I haven't sat down and done the math yet - I know F = GMm/r^2, so it's more a matter of me being lazy than ignorant). Unlike most planet-killers, their gravitational effect is fairly neglible, despite being the size of Texas (why, or WHY did Hollywood produce that wretched movie?). The second difference is that despite their mass, at a teaspoon in size, it's going to be difficult to observe as it moves through the heavens on its deadly mission. Yes, I know astronomers have multiple ways to detect things, but I know of no way besides observing gravity's shadow that this object could be tracked - making it practically invisible (dark matter anyone?). Third, I'm not sure what would happen when the neutron nugget (as I call it) impacts Earth, as unlike other planet-killers, this is much denser and much smaller. I'm thinking it would punch through Earth like an armor-piercing bullet through a flak vest rather than go hollow-point, but I'm not sure.

What I have so far is that this object is moving through intrastellar space at a good clip. Being extremely lazy here, I figured that if it didn't have any real movement, it would at least be hitting Earth at double the escape velocity. Give it a little push and add that push to the velocity for the final F = 1/2 mv^2. So this object enters the Earth-Luna intra-system and starts rivaling Earth for the new primary.

Ignoring the possibility of detecting its shadow (part of the plot, more fiction than science... swallow or ignore this if you must), the first sign of its passage would either be its effect on Luna or its effect on the geosynchronous satellites (which I believe are the furthest satellites we have... correct me if I'm wrong).

Depending on how fast this neutron nugget is going, where it enters the Earth-Luna system, and where Luna is at that time will determine what Luna does. Even impacting Earth at the polar region will screw up Luna's orbit, but since this is an outside force, it won't change the angular momentum of the original system (like it matters). Either the nugget will speed up Luna by attracting it closer to Earth, or it will slow it down by drawing it away. I BELIEVE this will not change Luna's face to Earth, but will cause a change in its position (a noticeable, detectable change), and a change in its size in the sky (as it moves closer or further away).

More likely though, the first noticeable effects will be the parts of the satellite system nearest the neutron nugget that suddenly get pulled out of alignment. Bye-bye GPS system and satellite TV! Unfortunately, I'm not sure what other effects this would do (by messing with the satellites, I mean). Probably a few of the satellites on the other side will be pulled in closer to Earth and will begin orbital decay, although at the speeds the nugget is going, impact of nugget will happen long before any satellite orbit impacts.

Playing with Luna and causing some people to miss the game is the least of Earth's problems. Assuming the neutron nugget is going twice Earth's escape velocity (22.36 km/sec), the nugget enters Earth's atmosphere. Now I don't recall what the speed of sound is, but I know it's nowhere near escape velocity, let along twice. Sonic booms seem to be dependence on two things; displacement and speed. Well, the speed is high, but the displacement is pretty small. Net effect? I have no idea, or at least, nothing for certain. On this, I claim both ignorance and laziness. What I think will happen is that the speed being so much greater will create a massive shock wave through the atmosphere that will start to travel around the Earth (I'm assuming the shock wave will overcome the effect of the gravity well, which I detail below).

In the few minutes before the impact, people will feel the sudden change in gravity as down almost certainly changes direction and increases in strength. Where the nugget enters the atmosphere, the air thins suddenly as the air molecules are attracted more to the nugget, and the surrounding air becomes an instant low-pressure system.

On the surface near the impact point, the sky starts to have a stronger pull than the ground. Clouds, dust, insects, birds and other air-born objects and particles suddenly are drawn up in the sky. At 6250 km or so (the radius of Earth), the impact point has reduced to a microgravity as the nugget's pull and Earth's equal. As the object gets closer, this microgravity effect will become a ring, expanding out over the surface, while inside the ring becomes that stronger pull mentioned earlier in the paragraph.

As some point, even air-born objects aren't enough to feed the nugget's gravity well. Animals, humans, loose objects on the ground become airborne, falling towards the neutron nugget. If the storm of objects doesn't kill anyone or anything unfortunately enough, the sheer gravity will do the rest. Trees become uprooted and structures are torn from their foundations.

Then the neutron nugget impacts the surface.

The accumulated mass that the nugget stolen in the form of plants, rocks, and animals is instantly converted into the standard impact explosion. As this "layer" is vaporized, the nugget punches through, continuing on its journey. The explosive force kicks enough dust into the air to guarantee a new Ice Age, as well as goes off like a nuclear blast.

For sake of argument, let's say that impact with Earth will produce instant terminal velocity. It probably won't, but I have no idea on how to figure out what the terminal velocity of a neutron nugget through crust, mantle, or core would be. The high-speed, high-energy invader will... what? Make a crater? Drill through the Earth? This is where I'm really grasping at straws and needing help. I can suppose quite a bit, but I have no clue how the energy of an impact crater model can be used to explain this.

The idea of a large crater being created doesn't seem correct to me, so I'm going to go with the drill-model. At more than 22 km/sec, assuming a square-on collision (not likely), the nugget will go through 12756 km of Earth in approximately 570 seconds, or 9.5 minutes. A plume of debris (possibly water too) will spike up at the entry point and then the rest will be pushed aside, making a vent through the Earth. Magma will raise to fill the vents, spurting out of the entry point.

The passage of the nugget through Earth is felt all over the planet. At 4.25 minutes, 285 seconds after impact, the nugget is at the center of Earth, and everyone and everything encounters 2g's. Up to that point, depending on where they were, the pull of "down" wasn't so much down anymore, but as it got closer and closer, it became more "down" and stronger.

I assume this would be causing all kinds of trouble in the forms of earthquakes, tremors, volcanism, maybe even fissures, but I really don't know for sure.

Then, 9.5 minutes after impact, the nugget punches through the other side of Earth. Everything on the other side feels the effect as the nugget increases gravity for them, pulling them "up." Like a reverse of what happened on the other side, the nugget rips out of the ground, kicking up debris hundreds of miles away. Magma from deep in Earth, aided by pressure from within and the gravity well of the nugget, makes a lucky oil strike pale in comparison. Many things are ripped away from Earth, but unlike what happened to the entry point, these things stay with the nugget as it travels into outerspace.

The shockwave from the exit, weaker but still quite powerful, ripples out around the globe. While the shockwave from the entry was enough to slough skin, the shockwave from the exit will probably only be enough to flatten buildings. However, when the two shockwaves collide, somewhere more on the exit side than the entry, the net effect is a ring of air suddenly leaving Earth's gravity well.

The real fun part is just ahead.

As I mentioned, the neutron nugget was only going twice escape velocity. Without additional power, and probably because it lost quite a bit in the punch, the neutron nugget is now too weak to escape the combined escape velocity of the two planets. I'm not sure how long it would take, probably more than an hour, but the neutron nugget will return to Earth and repeat the process, only doing less damage because it has less energy, and striking a different spot because Earth has rotated since then.

How many times this should take, I don't know. My big question to everyone patient enough to read this is: how accurate was this portrayal?

__________________
"So we fix our eyes not on what is seen, but on what is unseen. For what is seen is temporary, but what is unseen is eternal."
- Paul of Tarsus