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Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: !mater on 29/05/2011 02:47:41

Title: How would antimatter behave in the atmosphere?
Post by: !mater on 29/05/2011 02:47:41
Hi,

I'm currently working on a small rts mod, which includes a unit capable of "conjuring"(its ingame-magic ;) ) via teleportation pieces of antimater to attack. My Question is, how would those pieces of negative matter behave if dropped into a earthlike environment.

I know they would instantly start annihilating with the oxygen, creating massive amounts of gamma rays and heat, but that's were my assumptions end, and i decided to ask professionals.

If this speculation is considered to be too unscientific, please tell me and i will repost in off-topic.

Thx for answering

Regards

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Title: Re: How would antimatter behave in the atmosphere?
Post by: JP on 29/05/2011 05:49:52
Well, it's generally assumed that antimatter is attracted by gravity, just like regular matter, though this hasn't been tested yet (since getting a hold of enough antimatter is hard).  So the chunk of antimatter would fall.

But the major effect would be that it would annihilate any matter it touched instantly, releasing huge amounts of energy.  1 cc of anti-water, for example would release energy on the order of an atomic bomb. 
Title: Re: How would antimatter behave in the atmosphere?
Post by: !mater on 29/05/2011 09:09:24
Oh, so even if the unit would survive the hard rays and emp, it still would be engulfed in its very own nuclear explosion?  [:-'(]  Turns out this was a suicide mission all along - and the way i imagined it was completely wrong.

Mmmh.. i could encase it (like a artillery shell, i guess, the stored the stuff for a short period of time in CERN, i heard) But that would make it until impact just another -way -way -way overpowered rail gun. Impossible to stay halfway realistic and balance this out.

Is there something else in the kitchen of particle physics i could fire with this concept? Can even be yet-to-prove stuff, just shouldn't be completely ridiculous like the Anti Mater idea.


Post Scriptum: Thx for the swift answer
Title: Re: How would antimatter behave in the atmosphere?
Post by: JP on 29/05/2011 16:21:51
Well, you could use antimatter, but just use a lot less of it.  It could also be encased in some sort of "shell" as you say, such as a magnetic field which keeps it away from normal matter.

But what do you actually want this weapon to do?  Antimatter's main effect is to release a lot of energy when it meets normal matter, so any antimatter weapon will look like a big explosion.  If you want a different effect than that, there might be other options, but what effect do you want?
Title: Re: How would antimatter behave in the atmosphere?
Post by: yor_on on 29/05/2011 16:52:14
Why not try microscopic black holes :) Then combine them with the anti matter when you want them destroyed. You could use them to slow enemy action for example, ah, possibly :)

==

I wonder if that would work? Letting anti matter fall in to a event horizon?
Encased in some magnetic bottle.
Title: Re: How would antimatter behave in the atmosphere?
Post by: !mater on 29/05/2011 17:45:36
The actual plan was to use it as a close up shotgun unit (i figured out that annihilation would slow down any kind of not encased projectile). Rather imprecise..

Is there a sort of in-between mater to encase AM? Basically a Buckyball with only one AM-Molecule encased inside? For players  a EM-Field Grenade would look just like any other grenade...

So a mini-blackhole- hey that's a idea- lets presume i get it shot inside a unit, slowly eating away on it from the inside, no wait, the small black holes are rather unstable, aren't they? But a Combination of those two.. mater beyond the schwarzschildradius meets highly accelerated negative particles. Only one thing for sure, there would be Gama rays...

I also have some units who rather break the laws of physic, but having read a lot of the books of alastair reynolds tought me that some of the most interesting stuff happens, when you avoid the classical Star***"-and then a miracle happens".

Title: Re: How would antimatter behave in the atmosphere?
Post by: yor_on on 30/05/2011 00:40:15
I was thinking of those relativistic effects myself, assuming that you somehow by using several black holes created a strong gravitational field, preferably without tidal effects ripping people apart, you could construct a 'time machine'  for those caught in it relative your war, letting them 'out' at some preconceived time. And we don't really know if mini black holes will evaporate, or if we even can 'construct' them. It's all theory still, as far as I know.

But you could use it for fun effects maybe, and feeling yourself 'sucked up' by a black hole should make you think twice the next time before you go to war :)
Title: Re: How would antimatter behave in the atmosphere?
Post by: !mater on 30/05/2011 18:16:30
How would a miniature blackhole look like? I can imagine antimatter (white bright light, lightning and oxygen glowing in gama rays -> Would have been a nice lightshow) .. but a miniature blackhole.. thats basically a gravitylens and some caught oxygen ...

I know that the "blackholes" shown in other games are mostly stupid clichees.. black holes are invisible.. except for light missing..
Title: Re: How would antimatter behave in the atmosphere?
Post by: imatfaal on 30/05/2011 22:17:12
Black holes on a human scale are anything but black; a kilogram blackhole would burn for a tiny fraction of a second (10-17secs) at a an imaginable high temperature (10^23K) giving off a great amount of energy (10^17 joules). 
Title: Re: How would antimatter behave in the atmosphere?
Post by: JP on 31/05/2011 03:51:11
Black holes on a human scale are anything but black; a kilogram blackhole would burn for a tiny fraction of a second (10-17secs) at a an imaginable high temperature (10^23K) giving off a great amount of energy (10^17 joules). 

It sounds like this would pose the same problem as antimatter.  The black hole evaporates quickly, emitting all it's mass as energy.  Mass->energy conversion releases a huge amount of energy, which is why atomic bombs are so powerful, and why an antimatter weapon would produce such a huge explosion.  So a tiny black hole, rather than sucking things in, would basically make a huge explosion.

You could always use antimatter, but just use a tiny bit of it.  It would still "explode" and release huge amounts of energy when it contacts matter, but if you're talking about tiny amounts the explosion could be scaled way down. 

And if you're talking about teleportation, why not just teleport antimatter (or a regular explosive for that matter) inside of your target?
Title: Re: How would antimatter behave in the atmosphere?
Post by: yor_on on 31/05/2011 10:21:52
I got it :) Entangle the Black holes ::))

As for the evaporation, isn't that still theory?
Nobody can state that they know what a Black Hole will do, neither a mini black hole.
I just saw an ideas in where we all are 'made' from stable remains of 'mini Black holes' creating what we call particles, which ?? in a way makes sense, but not really. As if we assumed that we then also would have to assume that all is gravity, but also would have to define how that 'kaa' solidifies into particles.

But sure, it fits my idea of infinite energy/gravity in where we are the bubble constraining it. And so it makes sense to me. A Scenario for Strong Gravity in Particle Physics. (http://arxiv.org/abs/0905.1667)

I like that scenario because you will find a lot of things easier to explain from assuming that, as I think of it. And it also explain 'times arrow' in a better way, as the universe then could be seen as a 'stress fault' in something else with inflation and expansion being something that is rather natural for the containment to experience as it becomes a disturbance 'inside' something else.

0uch.
Title: Re: How would antimatter behave in the atmosphere?
Post by: imatfaal on 31/05/2011 11:08:05
As for the evaporation, isn't that still theory?

Well what isn't? 

The existence of Hawking radiation is widely accepted - but difficult to experimentally verify at present.
Title: Re: How would antimatter behave in the atmosphere?
Post by: yor_on on 31/05/2011 13:40:20
I have troubles with mini black holes. We have natural radiation stronger than the LHC but we haven't seen any 'mini black holes' explode anywhere, and we should be able too if they were 'constructed' today. We should be able to see it as far as the closest star according to some sources. The other way is to define them as 'constructed' at the Big Bang only, and that is what Hawking seems to do, as I understands it?

And black holes radiate at a lower temperature than the surrounding space as it is, and what that should implicate I'm not sure of? Either you can look at it as a impossibility as the only flow we know goes from warmer into colder, which then might mean? that a Black Hole radiation can't come to exist before it will be, hotter than the CBR?

On the other hand a Hawking radiation seems defined by broken entanglements which then leaves particles to populate our Universe, although created out of the Black Hole energy surrounding the Event Horizon. It's such a tricky subject this?
==

A natural effect from such a definition might be that if we were to make mini BH we could not be sure of their evaporation rate. And that would mean that they could stay longer than what we expect.

Title: Re: How would antimatter behave in the atmosphere?
Post by: imatfaal on 31/05/2011 14:07:55
I don't know the HEP behind mini-blackhole creation - but I would have thought even the highest cosmic rays would be too small when incident on a normal particle.

Large black holes are not net-radiators; if their hawking/bekenstein temperature is below that of the cosmic background (ie above 2.5K) then they are net absorbers of radiation, and will in a +ve feedback loop get colder and absorb more radiation.

the hawking mechanism is very easily explained in heuristic terms - but this shortcut leads to very little real comprehension.  This is the bit where my maths and physics gives out: 
Quote
It should be emphasized that these pictures of the mechanism responsible for the thermal emission and area decrease are heuristic only and should not be taken too literally. It should not be thought unreasonable that a black hole, which is an excited state of the gravitational field, should decay  quantum mechanically and that, because of quantum fluctuation of the metric, energy should be able to tunnel out of the potential well of a black hole. This particle creation is directly analogous to that caused by a deep potential well in flat space-time. The real justification of the thermal emission is the mathematical derivation given in Section (2) for the case of an uncharged non-rotating black hole.
S. W. Hawking, ‘Particle Creation by Black Holes’ Commun. math. Phys. 43, 199—220 (1975). Page 202
Title: Re: How would antimatter behave in the atmosphere?
Post by: JP on 31/05/2011 14:38:01
Also if they're tiny, such as might appear in a particle accelerator or from cosmic rays, I'd imagine they're such low mass that you would need to be looking at the right place at the right time to see one evaporate.
Title: Re: How would antimatter behave in the atmosphere?
Post by: imatfaal on 31/05/2011 15:30:06
Through simplistic guesswork I make the life time of a 14TeV black hole (ie about 10^-10grams) to be in the order of 10^-56 seconds. 

The most energetic cosmic ray interacting with a normal particle would be about 50 times more energetic than LHC collisions - this would increase the life time by a factor of about 10^5 - this is still unimaginable and unmeasureably quick
Title: Re: How would antimatter behave in the atmosphere?
Post by: yor_on on 31/05/2011 16:50:44
I don't know Imatfaal. The radiation should only come to be if the BH:s are 'hotter' that the cosmic background radiation? If there is one :)

We really need a *Black Hole* somewhere closer to us to study?
Postorder?
Title: How would antimatter behave in the atmosphere?
Post by: imatfaal on 31/05/2011 23:46:11
Yep  That's exactly what I said - blackholes of any decent size (ie that might be produced by a collapsing star) are far cooler than the surrounding space (ie cmbr 2.5K). These blackholes will get bigger and colder for many years to come ie till the cmbr has cooled thru expansion. 

By investigation of the orbits of the stars near the centre of our galaxy we can estimate that it has a minimum mass of 4 million solar masses within a space of max (and possibly lot lower) a few light mins ( I an writing this at the station so the figures might be wrong).  The only long term body that could have that density is a black hole.  I will dig out a recent reference that brought down the upper bound of the volume and concludes that the centre of milky way is very good proof of the existence of super massive black holes). 

Sorry for spelling - on iPhone waiting for last train home
Title: How would antimatter behave in the atmosphere?
Post by: !mater on 22/06/2011 16:14:35
So miniature black holes it is.. keeping them stable until they reach the target...

Teleportation is spectacular, as it seems to violate all (in free nature observeable)
laws, for everbody who knows something about physics. But for a game, teleportation is the simplest thing to do, and people wouldn't grasp why suddenly the enemy units inflate and then explode.




Another unit.. this time one, i know for sure that the idea works. This is the gamagardener... a robot, who deals longrange, longterm damage to organic units. I plan to use a blureffect for the radiation (i know x-rays are nearly invisible).. but how should the damage look like? Sunburns? Steam?



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Title: How would antimatter behave in the atmosphere?
Post by: imatfaal on 23/06/2011 13:58:12
!mater (is that click-mater like the african languages?) - do it like the rind of bacon when on a hot griddle
Title: How would antimatter behave in the atmosphere?
Post by: !mater on 26/06/2011 11:43:54
! as in negations, so anti-mater, results in negated mater or !mater. Now in retrospect it sounds rather wrong.

Okay, moving aliens will be crisp like bacon (should be doable by slow texture exchange)but what about trees and plants?

(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fimg585.imageshack.us%2Fimg585%2F962%2Flowetree.th.jpg&hash=151b2f8a3ed1a19384de7b61abd10ce9) (http://imageshack.us/photo/my-images/585/lowetree.jpg/)

I will have some of those in game, and should they just catch fire? If a tree is slowly roasted, he certainly would drop all his leaves (just don't cannonball this thread into some biology board, please). How do Rivers, and open water behave when under constant X-Ray Bombardment? Should the grass around the gardener look burned too?

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