A comet from another universe made of antimatter

[Tom Kalbfus]

What would happen if in the OTU on the outskirts of a system a comet was found to be made of antimatter? Lets say it was in the Regina System in the Spinward Marches, the first thing tha was noticed about it was the hard gamma rays coming from it when it interacted with the stellar wind. What would the local authorities do about it? Would they try to find out where it came from?

 

[AndrewW]

Don't let the Darrians investigate it...

 

[sideranautae]

Don't let the Darrians investigate it...

:lol:

 

[Reynard]

A comet made of anti-matter?! As a quick quote, they "usually range from 750 meters (2,460 feet) or less to about 20 kilometers (12 miles)". Do you really want to be near that? Pray it's just 'sitting' out there. You can't make contact with it.

Remember, it's an amount of matter that reacts with an equal amount of anti-matter and not some chain reaction. Still make a big bang in any amount. You could control it's vector by controlled streams of matter to create reaction to direct its movement. Unfortunately any chunks freed would love to touch a ship's hull. Thereafter, that area of space goes to serious Red Zone. Patrol vessels would have to routinely sweep the place clean of any sizable matter.

Even TL 15 doesn't do anti-matter so you now have a big chunk of lab experiment until it helps herald in TL 17 and primitive AM plants centuries later. Or you could weaponized it in magnetic bottles on a missile or torpedo...

 

[Condottiere]

I would thought it sparkles as it interacts with gas clouds, eventually attritioning away to nothing.

 

[AndrewW]

Even TL 15 doesn't do anti-matter so you now have a big chunk of lab experiment until it helps herald in TL 17 and primitive AM plants centuries later. Or you could weaponized it in magnetic bottles on a missile or torpedo...

The Darrians already did...

 

[Infojunky]

Doesn't one of the belts in the Marches have a significant percentage of Contra-terrain Matter as part of it's make up?

 

[Reynard]

Yeah..., we're still trying to explain that urban legend and don't pay attention to the black system defense boats.

 

[sideranautae]

What would happen if in the OTU on the outskirts of a system a comet was found to be made of antimatter?

Since the outskirts of a system is ~1 L.Y. out, there would be centuries to study it. No hurry

 

[Easterner]

Shionthy (2306) Asteroid Belt has AM swirling about inside it.

The Red Zone status is purely because of the AM danger to navigation. There are no interdiction fleets or satellites. Anyone can travel to the Shionthy habitats (no guarantee you arrive intact or at all). Belters actively seek AM and sell it to the 3I by the gram for 6-7 figures worth of credits. The locals make a fortune and the 3I gets the goods w/o risk to themselves. It is not a secret, however the Imperium doesn't advertise this, nor does Shionthy, most folk assume Red means keep out and that is done by the average traveller.

I further believe the Kinunir was returned to service after a long period of being missing.

However a novel called Fate of the Kinunir may have altered a number of the above premises.

So if the comet were found at Regina the PC's would be sent to Shionthy to get a couple of the best CT miners there and go get the comet, or pieces of it. Success would mean billions, fail probably means death.

 

[sideranautae]

Shionthy (2306) Asteroid Belt has AM swirling about inside it.

The Red Zone status is purely because of the AM danger to navigation. There are no interdiction fleets or satellites. Anyone can travel to the Shionthy habitats (no guarantee you arrive intact or at all).

Another OTU idiocy. If there were chunks of AM in a star system it would be lit up like a christmas tree due to constant impact with dust and solar wind. :roll:

If a 1 gram piece of space debris were to hit a chunk of those AM asteroids it would yield and explosion = to about 22 kilotons of TNT. It would shoot that asteroid in the opposite direction. Over the period of several thousand of years (blink of an eye really) there would be no more AM in that system...

 

[Tom Kalbfus]

Though space is quite empty. How often has a 1 gram of debri ever hit the International Space Station? Most impacts are with micrometerites. I believe an Antimatter Comet would last quite a while. A micrometerite might release the energy of a few sticks of dynamite.

 

[spirochete]

What would the local authorities do about it? Would they try to find out where it came from?

Attempt to capture & contain it.

LBB 3 shows antimatter as a TL 17 energy source, but in reality M=E/C², therefore antimatter takes far more energy to create than it would yield in a reactor. It just isn't practical. However, a harvest-able antimatter resource like this comet would be an energy industry game-changer. It has enough anti-substance to power billions of worlds at Earth's current annual level of consumption.

A cataclysmic collision with one of the system's planets (or star) is inevitable if it's not captured or diverted back into interstellar space. It could take millions of years but it will happen eventually.

 

[Reynard]

I found the dinosaur killing asteroid was about 6 miles (10 kilometers) in diameter. An AM comet of equal size... Now go ahead and calculate the approximate size and density of an AM comet of equal size then use this calculator.

http://edwardmuller.com/right17.htm

You better know what you're doing playing around with that thing!

"Significant amounts of antimatter cannot be accumulated, because no vacuum trap for antimatter could permanently protect against every stray particle from cosmic rays and other sources. It takes only a one such particle to put energy into the system and seriously disrupt its stability.)"

Also,"Any antimatter in our part of the universe is necessarily very short-lived (the antihydrogen atoms, for example, survived for only 40 billionths of a second) because of the overwhelming preponderance of ordinary matter, by which the antimatter is quickly annihilated."

In other word, significant quantities of AM within a solar system would have been wiped out a long time ago.

 

[Tom Kalbfus]

The actual density of hydrogen as it exist in interstellar space is on the average of about 1 atom per cubic centimeter. So how many cubic centimeters in a comet that has a volume of one cubic km? There are 100,000 cm in a km so a km^3 = 1,000,000,000,000,000 atoms in a cubic km of space, now how much mass is this? One mole of hydrogen is 2 kg which is 2 times avagodro's number of atoms and avagodro's number = 6.02214179*10^23 atoms of hydrogen in 1 kg. So the number of hydrogen atoms in a cubic km of space has the mass of 1.6605387831627258978902255305417*10^-9 kg. So plug this number into E=MC^2 and we get
149,448,490 joules of energy, or actually twice that which is 298,896,981 joules of energy. Lets say the comet is moving relative to the hydrogen atoms at 1 km/sec that means every time it moves into a new cubic kilometer of space it is colliding with 1,000,000,000,000,000 atoms of hydrogen, this releases 300 megajoules of energy or generates 300 megawatts of power in the form of gamma rays by definition. So you think an antimatter comet that is radiating 300 megawatts of gamma rays ought to be detectible by the Regina authorities? How does that compare with the radiation of the Sun. The Earth receives about 1400 watts per square meter, now if the comet was in the shape of a cube, it would have a surface area of 6,000,000 square meters, this comes to about 50 watts per square meter of the comet, so it basically has the same output as a 50 watt light bulb over its entire surface, but the wattage is in gamma rays so it would be quite invisible to human eyes.

 

[sideranautae]

Though space is quite empty. How often has a 1 gram of debri ever hit the International Space Station? Most impacts are with micrometerites.

Doesn't matter. You are STILL talking several kilotons worth of explosion. You missed the scientific point by several light years. PLUS, continual energy hitting the anti-matter.

 

[locarno24]

As noted, pure antimatter isn't really workable.

I'm trying to remember the mechanic in the Stephen Baxter novel which figured the idea.
As with most of his stuff it's handwavium but with slightly more respectable science behind it than generic science fiction.

Anti-Ice, from the shot story of the same name, was 'something wierd' - a super-high-temperature superconductor (i.e. freezing point) with antimatter in tiny amounts suspended in magnetic loops inside it. It's implied but never confirmed in the book that it wasn't natural in origin.

That doesn't eliminate things like highly penetrative cosmic rays but it means that generic dust or similar low energy particles strike the ice and abrate that slowly, only releasing and annihalating an anti-particle every so often. The stuff is easy(ish) to manipulate - kept cold enough it's essentially just ice, albeit with a wierd abrasive burning effect where it locally contacts things, but heat it up and it 'burns' more fiercely than any non-nuclear solid fuel could do.

Baxter used it as a fuel source discovered in the antarctic by the scott expedition which powered a sort of steam-punk vision of the 20th century.

It's probably still not viable on a stellar physics timescale, but it's enough that someone might see an ice comet cluster and investigate - and be very intrigued when the probe they send gets annihalated by what looks like a nuclear detonation on contact!

 

[Tom Kalbfus]

Though space is quite empty. How often has a 1 gram of debri ever hit the International Space Station? Most impacts are with micrometerites.

Doesn't matter. You are STILL talking several kilotons worth of explosion. You missed the scientific point by several light years. PLUS, continual energy hitting the anti-matter.

Potential explosion, the explosion only occurs if it hits a solid chunk of matter, but if it is only 1 hydrogen atom per cubic centimeter of space, an explosion does not occur, all you get is 50 watts of gamma radiation per square meter, now this could be 300 megawatts over the entire comet's surface, but that's spread over its entire surface, not in one spot, so there would be no explosion. Now if a gram of matter were to hit it in one spot, that might be enough to blow the anti-comet up into several chunks, a bit of a hazard, sort of like a natural mine field I would say, as you don't want your spaceship hitting any of those chunks!

 

[Reynard]

There's the point, no comet would glow with gamma radiation. Seems dead giveaway though I'm sure instruments in use today have no problem noticing the extreme unusual characteristics before them. That comet's going to be a self flashing WARNING sign.

Cosmic particles will be interacting with it constantly more so if it's deeper into a system. This becomes more pronounced if it has any movement exposing itself to fresh matter literally blazing a tunnel. It makes me wonder if being struck on one face continuously would cause a change in speed and direction almost like a slow motion pinball. If it's out in the ort cloud it could make contact with a comet cousin for a really big bang! In a system like Regina, it would be noticeable when the energy reaches the inner system. If the matter comet is too small for total annihilation, the AM comet might shatter sending high speed shrapnel to strike other comets for a nice fireworks display.

 

[sideranautae]

It makes me wonder if being struck on one face continuously would cause a change in speed and direction almost like a slow motion pinball. If it's out in the ort cloud it could make contact with a comet cousin for a really big bang! In a system like Regina, it would be noticeable when the energy reaches the inner system. If the matter comet is too small for total annihilation, the AM comet might shatter sending high speed shrapnel to strike other comets for a nice fireworks display.

Yes, when you look how frequently in one year that earth is pummeled with fair sized rubble, a comet spending thousands of years transiting an ort cloud (where materiel is relatively abundant) would be either blown to bits or, probably have its course reversed by the explosive reactions.