(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

Sounded very dramatic and would make a cool scene in a flim. I imagine however that more damage would be done to the earth by the tidal effect of this objects gravity. Earth would be torn to pieces by the changing forces of gravity it would be subjected to as this object approached and eventually struck, which of course would be the final blow and probably shatter the planet.

Anyone else fancy doing the maths......?

Very interesting scenario. I like it a lot better than the scenario from Armageddon, although the obscure nature of the threat would probably be lost on most of the movie-watching public. The only problem is that a mass of neutronium below the Chandrasekhar limit (about 1.4 solar masses) would decay into protons and beta particles after a relatively short time. A single free neutron does so after about 15 minutes. I don't know what the rate of decay of an amount of neutronium the mass of Earth would be, but it would require an understanding of general relativity, a subject I'm still pretty fuzzy on. An astrophysicist could render a more quantitative analysis.

Several nit picks.
1) You have seriously over stated the density of neutronium. A teaspoon of neutronium would mass about 100 million (10^8 ) metric tons. That's a lot, but still several orders of magnitude short of the mass of the Earth (6x10^21 metric tons).
2) It is unlikely that such a a small amount of neutronium could maintain its degenerate state and it would expand back to a more normal state. If my back-of-the-envelope calculations are correct, a chunk of neutronium the mass of the Earth (assuming it could exist) would be about 80 meters across.
3) Such a collision would shatter the Earth.

__________________
Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson

Good points all, Kaptain K.

One can always argue that the neutronium in question is not stable, but a slowly-decaying remnant of a larger chunk. Or, some process or environmental condition is keeping it stable artifically (certainly plausible if it's a weapon rather than a natural object).

But our OP is quite incorrect in thinking an Earth-mass neutronium sphere would not be a planet killer. It would be far more so than the asteroid/comet in the Armageddon/Deep Impact movies. Those might wipe out the Earth's surface, but a collision with the neutronium would totally destroy the planet, probably vaporize it (or at least completely melt it), and the planet that recondensed would be quite different from the Earth we know. For example, it would have twice the mass, thus much higher surface gravity, and its core would be neutronium (with iron outside that).

Even a near miss would probably be a planet-killing event. The tides around an 80-meter object with the mass of the Earth would be, well, astronomical. It could rip the Earth to pieces without even coming into contact with it! The Moon would be the least of our worries.

Think about it -- you're talking about shooting a planetary-scale mass into the vicinity of the Earth. That's not trivial, friends!

Now, if the amount of neutronium is the teaspoonful originally suggested, you're talking about something less massive than the "Armageddon" object -- more like Mount Everest. That could be nasty, but might not end civilization as we know it. Still, I wouldn't want to be anywhere near the impact site.

First of all, let me thank all of us you answered. You pointed out several things I needed to consider and where my idea lacks strong enough scientific backing.

I did a little more checking and research, and although I still need to double-check, I've found a few things that not only I missed or mistaken, but were not even considered.

For example, neutron stars are extremely hot (10^12 K when first formed, I believe, I need to double-check). Even a nugget would be hot enough that it would at least wither the nearby plantlife before obliterating it on impact. Whether it would be enough to flash-heat the weather or melt part of the impact site before the actual impact, I'm not sure.

Also, neutron stars have extremely powerful magnetic effects. That is sure to have an impact on Earth and the life that lives there, even if only briefly.

Next... tidal forces.

I'm sure these would be huge, and I definitely want to thank everyone for pointing those out again. However, I'm trying to wrap my brain around the exact details of the tidal forces. It would cause a bulge in the planet that would make Io's volcanism dynamo a firecracker in comparison, that's for sure. Of course, the power of gravity making the tidals would be swiftly countered by the force of the impact, but like I said, it's all in the details.

Quick sidenote, since this was mentioned. As stories go, this would be written, not film. If it got turned into a film, great, although I don't think the general public needs to worry about not getting the danger behind this threat. Make it clear that it's a neutron nugget, not something like a carboneous asteroid, and you're good to go. Those who understand or are swift enough on the uptake would pick it up - superdense object, small, but massing on scale equal to Earth.

Chandrasekhar limit - well, if a single neutron does so after 15 minutes, I can assume (easy math here) that neutronium has a half-life of 15 minutes. Not accurate, since I'm not sure that the decay of neutronium is exactly considered radioactive, but if it is, then that's another threat. The radiation from the neutron star will be extremely deadly (although I'm sure sunburn comes from UV, so I'm not sure how to incorporate this... maybe I need to do some more research on radiation. As far as the decay goes, it just means this is a short-lived weapon, once released. Should last long enough to do the job though.

Density of neutronium - come to think of it, a teaspoon did seem a little wrong. I should have known better. Of course, at 80 meters across, it now becomes detectable, so the hidden aspect is less. Of course, if this object is "warped" or "teleported" on the sunny side of Earth, where it has to impact soon before it decays away too much of its mass (or expands too quickly), the warning would be scant.

As far as it being a planet-killer - first, I didn't say it wasn't a planet-killer, I just didn't want to lump it with the category of the other planet-killers (i.e., just another really huge rock). Second, well, I'm trying for an artistic balance. Consider it the fine art of an alien's mindset on how much damage to use to wipe out everything on Earth without destroying the actual planet. Think of these creatures as saying "overkill is so gauche", and you have an idea of what I'm trying to obtain.

So shattering is okay, melting is acceptable, but vaporization is right out.

I'll post more after I've done more research on the matter.

__________________
"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

And then they would be saying things like this about your film:
And you'd have a few million in the pocket. Go for it!

The damage depends on the relative velocity. The greater the difference, the lesser the damage of a fly-by.

At extreme velocity, the weapon would experience time dialation and would increase longevity relative to the Earth.

A teaspoon of neutronium cannot exist in isolation. Strong force degeneracy pressure balanced against gravity is what keeps it together. If you don't have the appropriate amount of stuff, there isn't enough gravity and specifically radioactive decay will occur.

Niven wrote a short story featuring a neutronium body with the mass of an asteroid or thereabouts. Somehow it was in orbit around a planet and featured in the ultimate resolution of who owned the place. The story might have been called, There Is a Tide, but it's been a while. Regardless of who wrote it or when, JSP said it...neutronium doesn't want to exist in small quantities.

Physically untenable since you cannot separate out the stuff save for a catastrophic collision and even then the neutron star would have to be very close by. The rates of reaction would be phenomenally fast since there are no stable nuclei that last for more than microseconds above about 300 in atomic mass

You're going to have to invent some new physics to do this.

The problem is not with single neutrons which are far more stable than neutronium. If not for the gravitational force, massive nuclei would decay scaling with how massive the nucleus is.

Unfortunately, it's not going to be long enough.

Any neutron star entering our solar system would be observable when it was still well beyond the heliopause. I'm going to attend tomorrow a conference on single neutron stars, so I can give more information then.

A chunk of neutronium placed gently at rest on the Earth's surface may sink into the Earth. Like a lead ball in a cereal box. It may even free fall because Earth's rock material would feel like air from the point of view of neutronium. An interesting friction concept. The neutronium would fall toward the core but as it does so, the Earth's local gravity field drops to zero.

If the neutronium chunk doesn't pick up enough speed, it may come to a stop before reaching Earth's center because the little resistance offered by the Earth's material may be enough to slow the chunk in the weaker gravity field near the center. If it does pick up enough speed, it will overshoot the core and fall back, perhaps several times before coming to rest near the core.

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PS:: Sci~Fi Channel USA will start showing Cleopatra2525 in April.

Prime Time http://www.scifi.com/schedulebot/index.php3

11-APR-03 8:00 PM CLEOPATRA 2525 A QUEST FOR FIREPOWER
11-APR-03 8:30 PM CLEOPATRA 2525 CREEGAN

18-APR-03 8:00 PM CLEOPATRA 2525 FLYING LESSONS
18-APR-03 8:30 PM CLEOPATRA 2525 MIND GAMES

25-APR-03 8:00 PM CLEOPATRA 2525 HOME
25-APR-03 8:30 PM CLEOPATRA 2525 RESCUE

02-MAY-03 8:00 PM CLEOPATRA 2525 RUN CLEO RUN
02-MAY-03 8:30 PM CLEOPATRA 2525 CHOICES

09-MAY-03 8:00 PM CLEOPATRA 2525 PERCEPTIONS
09-MAY-03 8:30 PM CLEOPATRA 2525 TRIAL AND ERROR

16-MAY-03 8:00 PM CLEOPATRA 2525 DOUBLE
16-MAY-03 8:30 PM CLEOPATRA 2525 THE LAST STAND

30-MAY-03 8:00 PM CLEOPATRA 2525 HEL AND HIGHWATER, PART 1
30-MAY-03 8:30 PM CLEOPATRA 2525 HEL AND HIGHWATER, PART 2


Doubtful they will ever put out Region 1 DVDs so get VHS tapes ready.

Cleo Episode guide --> http://www.whoosh.org/epguide/cleo/cleo.html
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