Ask any question you want about Physics

If someone wanted to say, invent a method of faster than light travel, where do you suggest he should look? Wormholes are extremely far-fetched and warp drive has very little evidence to back it up.

a reply to: IAmTheRumble
I like someone who answers their own question!


Aside from trivial forms of faster than light travel, those two are the main candidates. This faq discusses those two and many trivial cases of faster than light travel:

Is Faster-Than-Light Travel or Communication Possible?

There's an ATS member who about once a year or so posts a thread answering the question in that link as "yes", but he doesn't understand the difference between correlation and communication and thus the answer is really no. If it is possible, nobody has been able to prove it yet. Quantum entanglement involves faster than light correlation between the entangled particles, but as Michio Kaku put it, this effect can't be used to send your grandma's cookie recipe faster than light, as far as we know, but I think there are people trying to see if they can actually do something like this.

originally posted by: IAmTheRumble
If someone wanted to say, invent a method of faster than light travel, where do you suggest he should look? Wormholes are extremely far-fetched and warp drive has very little evidence to back it up.

I thought you had already read the thread in my sig.

a reply to: Arbitrageur

Thanks for the link, I'll have a go at it now.

I remember watching a documentary about quantum entanglement with Brian Greene. If I recall corectly, I think he said the "state" of the atom can be sent to another location at FTL velocities but, you would need a container of matter to reconstruct the human body at the destination, using the states transferred. Not only that, how is someone going to entangle all the particles in someone's body with other particles millions of light years away...

This quest is not for the faint-hearted.

Do we have two electromagnetic fields, brain and heart?

a reply to: yulka

Those are meat, not fields.

a reply to: yulka
There are "billions and billions" just in the brain (which has about 100000000000000 synapses). Every dot in this video is a synapse which requires its own electromagnetic field to transmit a signal:

Visualizing the brain as a universe of synapses

Neurons are depicted in green; multicolored dots represent separate synapses.

originally posted by: Arbitrageur
Every dot in this video is a synapse which requires its own electromagnetic field to transmit a signal...

They really don't, you know.

Synapses toss little chemical packages across a gap to send a signal.

Neurons don't even use charge carrier flow to send signals per se, except between nodes of Ranvier.

originally posted by: Bedlam
They really don't, you know.

Synapses toss little chemical packages across a gap to send a signal.

Neurons don't even use charge carrier flow to send signals per se, except between nodes of Ranvier.

Some are electrical, some are chemical:

Synapse

There are two fundamentally different types of synapses:

In a chemical synapse, electrical activity in the presynaptic neuron is converted (via the activation of voltage-gated calcium channels) into the release of a chemical called a neurotransmitter that binds to receptors located in the plasma membrane of the postsynaptic cell. The neurotransmitter may initiate an electrical response or a secondary messenger pathway that may either excite or inhibit the postsynaptic neuron. Chemical synapses can be classified according to the neurotransmitter released: glutamatergic (often excitatory), GABAergic (often inhibitory), cholinergic (e.g. vertebrate neuromuscular junction), and adrenergic (releasing norepinephrine). Because of the complexity of receptor signal transduction, chemical synapses can have complex effects on the postsynaptic cell.

In an electrical synapse, the presynaptic and postsynaptic cell membranes are connected by special channels called gap junctions that are capable of passing electric current, causing voltage changes in the presynaptic cell to induce voltage changes in the postsynaptic cell. The main advantage of an electrical synapse is the rapid transfer of signals from one cell to the next.

originally posted by: Arbitrageur
There are two fundamentally different types of synapses:

Even gap junctions don't conduct electrons like a wire.

The ONLY place you get current flow as such is the saltation current between Ranvier nodes.

eta: I should clarify - current flow down the nerve.

The actual net current in a neuron is, other than saltation, through the membrane at right angles to the signal flow.

a reply to: Bedlam

Heart = 1
Brain = 1.000.000.000.000
Earth core = 1

Did i get it right?

a reply to: Arbitrageur

Heart = 1
Brain = 1.000.000.000.000
Earth core = 1

Did i get it right?

Envision the axon of a neuron as one of those long weenie balloons.

In the refractory period, an air pump inflates the balloon as far as it will go.

The wall of the balloon contains a pattern of little air valves. They do one thing. If they see the balloon deflating, they open as well, releasing air. If the balloon is deflated, or inflating, they close.

Some weenie balloons have little dart throwers at the end, which puncture the next balloon in line. Others have connections between one balloon and the next. These are the two sorts of synapse.

If the weenie balloon's body (a round balloon at the end of the weenie) decides that it needs to fire, it opens a valve in the area near where the weenie attaches. The weenie begins to deflate. As it does, the valves in the weenie wall also open, further deflating the balloon, until it's totally deflated. At that point, either the dart thrower at the far end of the weenie fires, or the connection bleeds sufficient air from the next weenie balloon that ITS valves start to open, deflating it as well.

The net flow of air is through the weenie balloon's wall, deflating it. In the weenie axon, some air goes one way, some another, in a sort of random pattern as it's sucked through the weenie wall valves. In terms of flow up or down the weenie, you can't say it's a net flow one way or the other, except through the wall.

After the weenie neuron is deflated, an air pump turns on and reinflates it for the next event. This is the weenie balloon nerve refractory period. During this period, the wall valves can't tell if a new deflation event is occurring or not, because of the turbulence, and thus during the weenie neuron reinflation period the weenie may not deflate correctly.

A wire is like an air duct full of bees.

When you put an air pressure difference between one side of the duct and the other, the bees are blown slowly down the duct. No one bee always travels down the duct. They randomly buzz around in the duct. But there is a net tendency for the bees to move from the high pressure end of the duct to the low pressure end, due to the wind. The air pressure difference we call voltage, the net number of bees crossing an imaginary plane in the duct at right angles to the bee flow is called current.

Neurons don't use bee flow. So they're not conducting bees like an air duct. The air flow in a weenie neuron is from the inside of the weenie to the outside, not down the balloon.

Three questions I want answering...

1. What is the nature of Dark Matter

2. What really happens at a gravitational singularity

3. Will the end be a Bounce a Crunch or Rip?

originally posted by: yulka
a reply to: Arbitrageur

Heart = 1
Brain = 1.000.000.000.000
Earth core = 1

Did i get it right?

Why do you want to count fields? First you have to define what you mean by an electromagnetic field. If you define the term broadly enough, even chemical reactions can't take place without electromagnetic fields... chemistry is based on them. So virtually every living cell in your body undergoing chemical processes has electromagnetic fields involved in those chemical processes.

The heart can't have one field either. Your heart muscles need to contract in a certain sequence.

"Earth core = 1"
I don't know if this diagram of the Earth's magnetic field at the core is completely accurate or not. It might be the right idea but surely it's not an exact representation.
www.usgs.gov...

Even if it was accurate, how do you want to count that, is it one, or three? I have no idea what you're trying to accomplish with "counting fields". Seems like it's better to understand what's going on than to try to count fields.

Magnetic fields in the core probably get much more complicated during pole reversals and especially at that time there is probably more than one any way you want to count.

originally posted by: Korg Trinity
1. What is the nature of Dark Matter

We'd all like to know. See the previous discussion and excellent post by ErosA433 who is our ATS expert on the topic.

2. What really happens at a gravitational singularity

I tend to agree with Michio Kaku that it indicates a breakdown of theory, or in other words, there probably isn't one. We don't know what to replace it with though.

3. Will the end be a Bounce a Crunch or Rip?

Probably none of those, but instead a Heat death of the universe or big freeze

originally posted by: yulka
Did i get it right?

I would say instead that any EM field you get from a critter is a byproduct of some other function, and not a primary signal.

originally posted by: Arbitrageur

originally posted by: Korg Trinity
1. What is the nature of Dark Matter

We'd all like to know. See the previous discussion and excellent post by ErosA433 who is our ATS expert on the topic.

I wasn't actually expecting anyone to answer this, as there is no answers to give. I am aware of the primary suspects.

2. What really happens at a gravitational singularity

I tend to agree with Michio Kaku that it indicates a breakdown of theory, or in other words, there probably isn't one. We don't know what to replace it with though.

In math we tend to use infinity quite a lot as a mechanic to contain certain structures or values. if however Infinity were to exist in reality it could not be contained and thus the entire universe would be infinite. Though it is important to state that there is much evidence to suggest that our universe is not in fact infinite but maybe part of an infinite structure.

Thus the very fact that infinity can exist means that a singularity could indeed exist.

So I disagree violently with Michio Kaku on this point and state that because we do not have the ability to describe something, does not mean that it does not exist.

I would still like to know what a singularity actually means though in terms of the physics... the math that would describe it would give us the key to well.... everything.

3. Will the end be a Bounce a Crunch or Rip?

Probably none of those, but instead a Heat death of the universe or big freeze

The RIP is just another term for Heat Death, I prefer RIP since it also is an acronym of Rest in Peace

There are some issues with Heat Death / RIP though. In this theory the expansion of the universe has got to a point where mater is so diffused that not even atoms can exist.

But there is a problem... the very force that is responsible for the acceleration in expansion 'Dark Energy' which is derived from the annihilation of virtual particles that arise from the quantum foam... would not be able to annihilate since the space between them would be expanding faster than the force that brings them together... the potential for those particles would be realized and we would have new particles appearing...

This is why I prefer the concept of the Big Bounce....

originally posted by: Korg Trinity
The RIP is just another term for Heat Death.

No, it's not. RIP includes "phantom energy" heat death doesn't.

This is why I prefer the concept of the Big Bounce

I think Big Bounce more or less died in 1998 or when the 1998 dark energy observations were confirmed within a few years after that. For the big bounce to happen, the expansion would need to slow down and eventually reverse to contraction.

I say "more or less died" because some people seem to want to hang on to it, so the idea isn't buried completely, but the accelerating expansion of the universe discovery in 1998 would seen to make the bounce less likely, right?

originally posted by: Arbitrageur

originally posted by: Korg Trinity
The RIP is just another term for Heat Death.

No, it's not. RIP includes "phantom energy" heat death doesn't.

I haven't heard the term Phantom energy for many many years, not since we re labeled the concept dark energy. Although on paper that is correct, it doesn't conform to the observation of an accelerating expansion, and thus when we talk about heat death we are talking about the same thing as the big rip.

This is why I prefer the concept of the Big Bounce

I think Big Bounce more or less died in 1998 or when the 1998 dark energy observations were confirmed within a few years after that. For the big bounce to happen, the expansion would need to slow down and eventually reverse to contraction.

I say "more or less died" because some people seem to want to hang on to it, so the idea isn't buried completely, but the accelerating expansion of the universe discovery in 1998 would seen to make the bounce less likely, right?

It isn't that people want to hang onto it, there is evidence to suggest this is how the universe works. There are two main concepts behind the bounce that I am aware of.

The first I have already explained, in essence the concept of a static universe is the only value that is impossible, given that the natural order of chaos gives rise to particles that would normally annihilate each other. But in a heat death / rip scenario they would be unable to and thus we would have matter re-injected into the universe.

The second one is harder to explain, but the concept is based upon M-theory and causes a periodical cyclic big bang, caused by mono dimensional membranes colliding causing a kind of interference pattern which gives rise to a multidimensional space-time.

originally posted by: Korg Trinity
I haven't heard the term Phantom energy for many many years, not since we re labeled the concept dark energy.

The terms are not synonymous. Phantom energy is an extreme form of dark energy, not part of the standard cosmological model which relies on the cosmological constant.

Big Rip

Phantom energy is a hypothetical form of dark energy that is even more potent than the cosmological constant