Ask a physicist anything. (5)

[mzungu]

He said 3.8 cm per year. If this is true then at about the 1 Billion year mark would not the gravitational effect of the Earth and Moon cause destruction on the Earth? Since the gravitational effects would not be linear but exponential the closer they are.

Tidal wave and Hurricane force wind would be a understatement would they not?

You don't have to worry about such things my good man! Once the moon flees from the gravitational pull of the Earth then in all probability the moon will collide with one of the solar systems bodies and the Earth will loose its stability and start to tumble. Suffice it to say that bacteria will in all probability survive!

 

[Wiccan_Child]

Then there is really no way of ever knowing the original origin, Scientifically speaking. Because we can only go back to the last bang. Is that fair?

At the moment, but it's entirely possible that scientific knowledge will advance in the future. We learn more every day, so who's to say we won't uncover the universe's ultimate origins one day?

He said 3.8 cm per year. If this is true then at about the 1 Billion year mark would not the gravitational effect of the Earth and Moon cause destruction on the Earth? Since the gravitational effects would not be linear but exponential the closer they are.

Tidal wave and Hurricane force wind would be a understatement would they not?

Do you mean 1 billion years in the past, or 1 billion years in the future?

If the former, 1 billion years ago, the gravitational affects would not have been as devastating as you might think. Stronger, sure, but not cataclysmic. The Moon is ~4x10[sup]8[/sup] m from the Earth at the moment, and, assuming a constant 30mm recession per year, would have been ~3.7x10[sup]8[/sup] m from the Earth a billion years ago. Note that I've overstated its recession rate and understated its current position; the difference in reality is even smaller.

So it's only gotten 8% further away in the past billion years. Not a whole lot, really.

 

[Naraoia]

My area of research was complex systems and, as you may or not know, ecological systems are very complex. There is great mathematical models for biological systems. The problem is that it is not biologists making these models, it is basically physicists. Physicists don't really understand the nature of biological systems therefore these models are generally terrible. The hope would be that biologists will listen to the physicists and start taking control of their area.

That sounds like a bit of a bull**** generalisation, to be honest.

Seriously, Per Bak once said to Stephen Gould "would it not be nice to have a theory for punctuated equilibrium?" Gould was of the impression that PE was a theory. Bak was of the opinion that such attitudes were quaint and that biologists should get a cookie and let the actual scientists do their work. As a biologist, are you going to take that poop from physicists?

Physicists can stuff their arrogance up an orifice of their choosing

And nowhere does the scientific definition of "theory" include equations.

I believe you are doing a doctorate? That you are a training academic, right? If you are not I sorry for what I am about to say*:

Get a sense of your ovaries, women. You must develop your understanding of a topic not someone else's understanding of a topic. If you believe that not understanding a topic, after reading one person's understanding, is sufficient reason for you to give up....you are either an uneducate undergraduate or an idiot.

Chill out, man. That "one book" thing was hyperbole.

 

[1611AV]

You don't have to worry about such things my good man! Once the moon flees from the gravitational pull of the Earth then in all probability the moon will collide with one of the solar systems bodies and the Earth will loose its stability and start to tumble. Suffice it to say that bacteria will in all probability survive!

At the moment, but it's entirely possible that scientific knowledge will advance in the future. We learn more every day, so who's to say we won't uncover the universe's ultimate origins one day?


Do you mean 1 billion years in the past, or 1 billion years in the future?

If the former, 1 billion years ago, the gravitational affects would not have been as devastating as you might think. Stronger, sure, but not cataclysmic. The Moon is ~4x10[sup]8[/sup] m from the Earth at the moment, and, assuming a constant 30mm recession per year, would have been ~3.7x10[sup]8[/sup] m from the Earth a billion years ago. Note that I've overstated its recession rate and understated its current position; the difference in reality is even smaller.

So it's only gotten 8% further away in the past billion years. Not a whole lot, really.

Yes I was talking the past.

Thanks for the math. One other question about the moon, I have heard recently that the moon is getting smaller in size due to its continuing cooling. Do you know of this and if so, what do you think about it?

 

[Wiccan_Child]

Yes I was talking the past.

Thanks for the math. One other question about the moon, I have heard recently that the moon is getting smaller in size due to its continuing cooling. Do you know of this and if so, what do you think about it?

I've heard of this, and while there isn't a lot of material on it, it appears the Moon has shrunk by about 100m, or about 0.005%, over its 4.5 billion year lifetime. It's shrinking due to cooling, but not by very much.

 

[mzungu]

Very good Documentary, worth watching:

Can You Hack It? – Hackers Wanted | Watch Free Documentary Online

 

[Maxwell511]

That sounds like a bit of a bull**** generalisation, to be honest.

Of course it is a generalization. Any statement about a group of people must logically be a generalization.

Also all generalizations miss details and are therefore bull****, so I would agree that it is a bull**** generalization.

But as George box says, "All models are wrong, but some are useful". So I am wondering is it a useful generalization in understanding the relationship between theories of biological systems presented by biologists and theories of biological systems presented by physicists.

As an example of this weird relationship: My SO studies human muscles and creates mathematical models of their contraction rates based on ion concentration etc. At a conference she was asked by a physiologist, I guy that studied muscles for years and years, "How can you use mathematics to describe muscle action?". In the sense that it is impossible to do so. She was dumbfounded by this question because her position was anything can be described by equations.

Maths is a language like French or German. If you can describe a scientific theory in English you can describe it in French and you can definitely describe it in Maths since maths is a language. We like maths because it is more applicable to deducing predictions. It is easier, for example, to talk about QM in mathematical language in order to make predictions. You can completely describe QM in English, and make predictions, however that would require too much work.

We really don't understand how biologists seem to not understand that a) maths can be used to describe biological systems and b) that doing so could be really useful.

Honestly all the above is bull**** generalizations and you know more about this than me. I would be really interested in your ideas about the relationship between biological studies and maths. If you have time. Maybe you could start an "Ask a biologist anything thread". I am incredibly ignorant of your position.

Physicists can stuff their arrogance up an orifice of their choosing

We are talking about a group of people that think if they form a consistent theory in their field that that would be a "Theory of Everything". I would like it to be explained to me how uniting the forces of nature under one paradigm would explain why Zebras have stripes rather than spots, however for physicists this seems to be a given.

Some also seem to think that there is physics and all other sciences are "stamp collecting".

The Per Bak guy literally wrote a book called, "How Nature Works". That would be equivalent to you forming a hypothesis on the system you are studying and saying that applies to all of the universe.

Arrogance seems to be par for the course for physicists. I think that we should let them have their bottle. They do sometimes produce good ideas.

And nowhere does the scientific definition of "theory" include equations.

The prepositions is not that a scientific theory has to be written in mathematical language. It is that if it can be written in English or any other language it can be written in mathematics.

Almost everyone is great at mathematics. The problem is that most people cannot read mathematical equations. Saying you are bad at maths is akin to saying that I am bad at biological evolution because I do not speak English and the "Origin of the Species" is written in English. It is an issue about representation of the concepts.

Chill out, man. That "one book" thing was hyperbole.

Sorry I went on a bit of a rant there, didn't I?

I was just concerned that you were under the opinion that you were incapable of understanding certain topics. You are not. The only heresy in academia is not having a wrong opinion but saying that you are incapable of forming an opinion.

The majority of things that you will read, you will not understand. The reason you will not understand it is not because you are stupid, it is because your current knowledge is not sufficient to make connections with that new knowledge. There is nothing wrong with that. There is something wrong with thinking that you cannot understand something beyond an "informal understanding".

 

[Wiccan_Child]

Very good Documentary, worth watching:

Can You Hack It? – Hackers Wanted | Watch Free Documentary Online

It's a clever system, challenging hackers to crack your software - then patching up the exploits they found. No work, great publicity, and free upgrades!

 

[TerranceL]

Very good Documentary, worth watching:

Can You Hack It? – Hackers Wanted | Watch Free Documentary Online

Thank you for the link.

 

[Naraoia]

I've heard of this, and while there isn't a lot of material on it, it appears the Moon has shrunk by about 100m, or about 0.005%, over its 4.5 billion year lifetime. It's shrinking due to cooling, but not by very much.

Speaking of which, that would be true of the earth as well, right?

(How the heck did anyone arrive at that 100 m number? Take something we know about the moon, make some assumptions, cook up a function and extrapolate?)

 

[mzungu]

Speaking of which, that would be true of the earth as well, right?

(How the heck did anyone arrive at that 100 m number? Take something we know about the moon, make some assumptions, cook up a function and extrapolate?)

It is done on a daily basis in the moulding industry. If you know the material composition then you can calculate very accurately the shrinkage!

 

[mzungu]

It's a clever system, challenging hackers to crack your software - then patching up the exploits they found. No work, great publicity, and free upgrades!

The only problem is that most good willed hackers ended up in jail.

Big corporations will rather suffer a real break in than to admit that they had a loophole in their system.

It is well worth watching the whole documentary as there are parts that will make you think twice!

 

[Wiccan_Child]

Speaking of which, that would be true of the earth as well, right?

(How the heck did anyone arrive at that 100 m number? Take something we know about the moon, make some assumptions, cook up a function and extrapolate?)

Because the Moon's surface doesn't erode or undergo tectonic reshuffling, the effects of shrinking over the past several billion years are still there. I don't know the ins and outs of it, but it seems that cracking on the surface can show us by how much its shrunk.

And, yes, there's probably some extrapolation too

 

[leftrightleftrightleft]

Can anyone explain the idea of entanglement?

How does one set up an experiment to detect entanglement?

Also, if you are a physicist at the LHC and you do an "experiment" in which you watch as a two streams of protons collide to form gluons and quarks and whatnot, what are you actually seeing? And what are you seeing it on? A computer screen? And what kind of computer can detect such particles? How can such particles even be "seen" if they are smaller than the wavelength of light?

 

[mzungu]

Can anyone explain the idea of entanglement?

How does one set up an experiment to detect entanglement?

Also, if you are a physicist at the LHC and you do an "experiment" in which you watch as a two streams of protons collide to form gluons and quarks and whatnot, what are you actually seeing? And what are you seeing it on? A computer screen? And what kind of computer can detect such particles? How can such particles even be "seen" if they are smaller than the wavelength of light?

Have you ever seen contrails in the sky when a high flying airplane is passing by? What you see is the evidence the plane leaves behind in the form of a disturbance that causes condensation. Similarly what the scientists see are the trails of disturbance and not the particles themselves. Also the disturbance can say a lot about the object that caused it.

 

[Wiccan_Child]

Can anyone explain the idea of entanglement?

How does one set up an experiment to detect entanglement?

When two particles are created (e.g., a high-energy photon (gamma ray) creating an electron and a positron), those two particles are forever entangled with one another. Quantum mechanically, we cannot describe one without mentioning the other. Such particles created in pairs are how we generate entangled particles.

Also, if you are a physicist at the LHC and you do an "experiment" in which you watch as a two streams of protons collide to form gluons and quarks and whatnot, what are you actually seeing? And what are you seeing it on? A computer screen? And what kind of computer can detect such particles? How can such particles even be "seen" if they are smaller than the wavelength of light?

The principle machines in the LHC are four enormous detectors, named ATLAS, LHCb, CMS, and ALICE (the last one is shown below, under construction), as well as the smaller, more specific TOTEM and LHCf detectors:

The massive ring that you see in pictures of the LHC is the huge ring of magnets to speed the particles up to nearly the speed of light. They are also used to ensure these particles collide exactly in the centre of these four detectors. This is a cut-away diagram of the CMS detector, showing how various particles interact with various parts of the device before being detected in their own way:

It's basically rings of detectors, each measuring particular things, and each detector measures different things:

1. ALICE ('A Large Ion Collider Experiment') is looking for quark-gluon plasma resulting from collisions between heavy ions, as notably, quarks have never been isolated before.
2. ATLAS ('A Toridal Lhc ApparatuS') is a broad-range detector, looking at how established particles behave under high energies.
3. CMS ('Compact Muon Solenoid') is designed to look for the infamous Higgs Boson, and to compliment the work with ATLAS.
4. LHCb ('Large Hadron Collider beauty') studies antimatter and mesonic physics, principally attempting to explain why there is more matter than antimatter in the universe.

This is the sort of output scientists see:

It looks complicated, but there are thousands of scientists working at the LHC who will carefully analyse this information. Sufficient data is collected by the machines that we can work out which lines refer to which particles - and any anomalous particles will be evidence of brand new physics!

 

[Chesterton]

LHCb ('Large Hadron Collider beauty')

Why is it called "beauty"?

 

[Wiccan_Child]

Why is it called "beauty"?

Because physicists are historically poetic . Quarks come in six 'flavours': up, down, top, charmed, and strange. Unlike these five, the sixth flavour never really settled on a single name: some called if 'bottom', some called it 'beauty'. 'Bottom' is slightly more popular than 'beauty'.

The 'top' quark used to be called 'truth', and still is among a larger minority og German physicists, which is rather nice.

Their names don't relate to anything specific about their properties. 'Strange' quarks are so called because they were just that: strange quarks. Up and down quarks are the most common and the most useful, since they make up protons and neutrons, but their names are just historical convention.

So why is the LHCb called 'beauty'? Because, among other things, it looks at collisions between so-called 'B-heavy' particles - that is, mesons whose composition includes a bottom (or beauty) quark.

 

[Chesterton]

Ah. Veddy interesting!

 

[Naraoia]

So why is the LHCb called 'beauty'? Because, among other things, it looks at collisions between so-called 'B-heavy' particles - that is, mesons whose composition includes a bottom (or beauty) quark.

Wonder why it's not "LHC bottom"