Science Updates

[Outlaw Yogi]

What I was alluding to is that the equaision E=mc2 is only theoretical, as we don't yet have the techno-infrastructure to properly test the theory.

Los Alamos National Laboratory and Lawrence Livermore National Laboratory would both like a word with you. They've only been designing, manufacturing, and testing mechanical proofs of E=MC^2 that the US Government has used as the basis of our Nuclear Deterrent Force for over six decades now.

When I went to school (until early 80s) light was considered a constant. Now if light was a constant it would always travel in a straight line (exceptions being reflection & refraction), but the immense gravity of black holes literally bends light. This is because even photons, however minute, still have mass, which is what the gravity affects, and why light gets sucked into black holes. Thus light is not a constant.

Think of space as a flat sheet with the large mass exerting gravity in the center of it. When light passes close enough to that mass, the gravity that mass exerts bends space, which in turn causes the light to alter its trajectory. The light is still going in a straight line, space is what is bending. The greater the mass, the greater the gravity and the more pronounced that curvature. Eventually that curvature can become so great that no matter what direction you go all points lead back to the point exerting the gravity.

In the case of a black hole you're dealing with something exerting infinite gravity, which locally turns space into a closed curve, meaning no matter which why the photon goes it's heading for the singularity. At no time does the photon's velocity or trajectory change.

If you'd like a more precise explanation I'd suggest learning German, getting really good at math, and then try and wrap your brain around Einstein's theory of general relativity. Good luck with that.

As for mentions to vacuum, well that's a moot point, considering space acts as the vacuum.

Seriously, and through the vacuum of space, which no outside mechanism interfering with it, the speed of light is a constant. This was stuff I covered in Junior High science class. It isn't rocket surgery, bro.

Damn, wanted to reply. Library closing for lunch .. another time hopefully

[Rorschach]

http://www.news.com.au/technology/desig ... 6821061499

THE world's oceans are big, dark and full of mystery. How to unlock the secrets of the deep? With the SeaOrbiter - a gigantic, solar-powered, floating aquatic observation vessel that will scour the seas non-stop for new life and sunken civilisations.

It might look like something out of a James Cameron dream but this 190ft tall floating behemoth is taking to open water as the world's first non-stop exploration vessel, complete with submarine drones, underwater living quarters and space training simulator.

[Super Nova]

When I went to school (until early 80s) light was considered a constant. Now if light was a constant it would always travel in a straight line (exceptions being reflection & refraction), but the immense gravity of black holes literally bends light. This is because even photons, however minute, still have mass, which is what the gravity affects, and why light gets sucked into black holes. Thus light is not a constant.

Gravity bends space in this instance, so the light does continue to travel in a straight line. It's just that those straight lines are bent by the mass of the black hole.

So from that explanation I would assume, space rather than just being vacant areas of nothing, is actually particles of something, and that something has mass .. ?

My understanding is that space does contain energy. That particles come and go out of existence in space. There is no space without energy at least at the level of the background radiation from the Big bang. Energy has mass.

However, the speed of light in a vacuum, that is, it is not travelling through a medium, is constant as is the fastest speed that can be achieved. We have not shown that light has mass however I think it must since energy and mass have a tight relationship. For the purposes of most equations we assume (they say it is proven, I am not sure it is) light is a massless particle/wave.

Does light have mass?

The short answer is "no", but it is a qualified "no" because there are odd ways of interpreting the question which could justify the answer "yes".

Light is composed of photons so we could ask if the photon has mass. The answer is then definitely "no": The photon is a massless particle. According to theory it has energy and momentum but no mass and this is confirmed by experiment to within strict limits. Even before it was known that light is composed of photons it was known that light carries momentum and will exert a pressure on a surface. This is not evidence that it has mass since momentum can exist without mass.

http://www.weburbia.com/physics/light_mass.html

The apparent bending of light around a heavy mass is due to the curvature of space rather than light be affected by the gravity on it's tiny mass. Light travels in a straight line through this curved space. (I know you know that)

[Chard]

My understanding is that space does contain energy. That particles come and go out of existence in space.

At the quantum level this is true. However, that means precisely ick where general or special relativity is concerned (neither has anything to do with quantum physics of any kind and physics has spent the better part of a century now trying to get Einstein and Bohr's two theories to actually make sense together with not much success).

Energy has mass.

No. Just no. Mass is a property of matter.

The apparent bending of light around a heavy mass is due to the curvature of space rather than light be affected by the gravity on it's tiny mass. Light travels in a straight line through this curved space. (I know you know that)

No. The photon appears to bend around the mass exerting gravity because space itself bends, not because the gravity has any effect on the photon itself. The photon has no mass for gravity to exert force on.

[Super Nova]

My understanding is that space does contain energy. That particles come and go out of existence in space.

At the quantum level this is true. However, that means precisely ick where general or special relativity is concerned (neither has anything to do with quantum physics of any kind and physics has spent the better part of a century now trying to get Einstein and Bohr's two theories to actually make sense together with not much success).

True. However there have been attempts at the fringes to unify their relative effects IE hawking's radiation.

The standard model is so complex and ugly I think there must be a lower level fundamental understanding we have not reached. Only then will the be unified.

Energy has mass.

No. Just no. Mass is a property of matter.

Then help me understand why an object increase in mass as the energy of the object increases. My understand (an I could stand corrected).

For example. I have water at zero degrees Celsius in a liquid state. I weight it. Then I boil the water increasing the energy of the water. If I weight this water it would weight more. It's mass has increased. (note, you would need to most sensitive scales) {note: this must be a myth I have picked up somewhere......]

I need to look into this more.

A so-called massless particle (such as a photon, or a theoretical graviton) moves at the speed of light in every frame of reference. In this case there is no transformation that will bring the particle to rest. The total energy of such particles becomes smaller and smaller in frames which move faster and faster in the same direction. As such, they have no rest mass, because they can never be measured in a frame where they are at rest. This property of having no rest mass is what causes these particles to be termed "massless." However, even massless particles have a relativistic mass, which varies with their observed energy in various frames of reference,
http://en.wikipedia.org/wiki/Mass_in_special_relativity

Also I probably am confusing relativistic mass and rest mass. As they are both traditional concepts in physics, but the relativistic mass corresponds to the total energy.

Just found the answer..... after I typed the above.

"...When a particle is energized, say in an accelerator, increasing its apparent mass (m=E/c^2), does gravitational mass also increase or does it remain the same as non energized mass?..."

The particle, or any other high-velocity body, does not actually become more gravitationally massive in its reference frame. The increased mass you mention is what's called 'relativistic mass' and is only different to someone observing from a different reference frame.

It's all about the reference frame..... need to do more reading when I get a chance.

The apparent bending of light around a heavy mass is due to the curvature of space rather than light be affected by the gravity on it's tiny mass. Light travels in a straight line through this curved space. (I know you know that)

No. The photon appears to bend around the mass exerting gravity because space itself bends, not because the gravity has any effect on the photon itself. The photon has no mass for gravity to exert force on.

That is my understanding also, however I was speculating that light has some mass. I know that the theories mandate that Light is massless. It is the curvature of space that the light, following a straight line, appears to be bending from an external reference point.

[Chard]

True. However there have been attempts at the fringes to unify their relative effects IE hawking's radiation.

No, Hawking Radiation is a theoretical kind of black body radiation caused by quantum mechanical effect. Has nothing to do with either general or special relativity.

The standard model is so complex and ugly I think there must be a lower level fundamental understanding we have not reached. Only then will the be unified.

The Standard Model also is the closest approximation to the underlying mechanics of the universe we have. Turns out that simple and short might not be the best answer.

For example, in Einstein's theory of special relativity, the famous E=MC^2 mass-energy equivalence equation, looks elegant enough to fit on a t-shirt. Problem is, it only accounts for how matter and energy are related under a special case. It doesn't account for gravity, time, space or quantum anything (Eisenstein hated the very idea of Quantum theory, calling it "Spooky action". Turns out Eisenstein was wrong and Bohr was right, but that's another discussion entirely). With General Relativity, Eisenstein attempted to unify space, time, and gravity and wouldn't you know it, but there isn't a single equation in it that could even remotely be called "simple".

Sometimes complexity is required, especially when dealing with complex subjects. Doesn't get any more complex than trying to mathematically express how the entire universe works at all levels.

Then help me understand why an object increase in mass as the energy of the object increases. My understand (an I could stand corrected).

Yes, mass and energy related as per special relativity. In this case as you increased velocity or energy state, that energy becomes mass. The opposite happens in nuclear fission where some mass is lost and converted to energy. Energy itself, however, has no mass.

For example. I have water at zero degrees Celsius in a liquid state. I weight it. Then I boil the water increasing the energy of the water. If I weight this water it would weight more. It's mass has increased. (note, you would need to most sensitive scales) {note: this must be a myth I have picked up somewhere......]

You wouldn't just need ultra sensitive scales, you'd need the sort of energy states normally associated with partical accelerators, nuclear weapons, or stellar fusion to make that change in mass noticeable.

Also I probably am confusing relativistic mass and rest mass. As they are both traditional concepts in physics, but the relativistic mass corresponds to the total energy.

Yup.

It's all about the reference frame..... need to do more reading when I get a chance.

Yeah, all of that only applies if the object in question had mass to begin with. Just as a photon will move at the speed of light no matter what the frame of reference is, it is always massless no matter the reference frame otherwise it would require infinite energy to move as it does because it would also have infinite mass, both of which are things that tend to make physics cry.

That is my understanding also, however I was speculating that light has some mass. I know that the theories mandate that Light is massless. It is the curvature of space that the light, following a straight line, appears to be bending from an external reference point.

Now ya got it.

[Rorschach]

Important step in fusion experiment
* by: John von Radowitz
* From: AAP
* 4 hours ago February 13, 2014 5:46AM

AN important step has been taken towards an era of virtually limitless energy from the nuclear reactions that power the sun.

Scientists at a fusion power facility in the US have succeeded in tipping the balance between energy input and output to achieve a net gain.

The result falls short of "ignition" - the "Holy Grail" of fusion science, which would generate more energy than the total amount needed to operate the reactor - but is still seen as a turning point.

A team at the National Ignition Facility (NIF) in California used 192 lasers to heat and compress a small pellet of fuel, a mixture of deuterium and tritium (DT), until its atoms began to collide and fuse.

By carefully tuning the laser pulses to maintain stability, the scientists produced an energy yield 10 times greater than any achieved before.

Crucially, the fusion energy obtained exceeded the amount of energy absorbed by the fuel to trigger the reaction.

This is not the same as generating more than the total energy needed to compress the fuel pellet, which is necessary for ignition.

"There is more work to do and physics problems that need to be addressed before we get to the end," said lead scientist Dr Omar Hurricane, who led the research, reported in the journal Nature.

"But our team is working to address all the challenges, and that's what a scientific team thrives on."

Nuclear fusion powers the sun and other stars, and is also responsible for the devastating destructive force of a hydrogen bomb.

A peaceful application of the technology could provide almost limitless supplies of clean energy from special forms of hydrogen, the most abundant element in the universe.

Deuterium and tritium are two "heavy" isotopes, or atomic strains, of the gas.

Two different approaches towards fusion power are being tested by scientists.

One confines the super-heated fuel in a magnetic field.

The other, adopted by the NIF scientists, relies on high energy lasers to compress and heat the fuel until it implodes.

A key element of the "inertial confinement" laser technique is known as "boot strapping".

This is when subatomic alpha particles produced by the reaction deposit their energy into the DT fuel, rather than escaping.

The particles further heat up the fuel, increasing the rate of fusion reactions and releasing more alpha particles.

Eventually it is hoped the feedback effect will lead to ignition.

[Chard]

If I had a nickle for every time I've heard some schmuck journalist say nuclear fusion for peaceful energy is right around the corner I could hire Bill Gates as my pool boy. NIF's ginormous laser is neat, but the problem is the reaction can only go on for as long as there is fuel (also you have to maintain exact temp and pressure or the process will stop entirely). So using their system of laser inertial confinement simply cannot function as a power source since you have to stop the entire process, let everything cool down and wait for the radiation to die down a bit before you can reload it and begin the process again.

This all of course ignores that the primary purpose of NIF is only tangentially related to nuclear fusion for power generation. NIF, like a lot of the huge toys operated by LLNL or LANL are meant to study what's going on in a thermonuclear weapon (the hippies won't let us do live fire weapons tests, so we built huge fucking machines to simulate it).

Also, if you want to see what the NIF looks like on the inside, just go watch the latest Star Trek movie. All the scenes of the new Enterprise's warp core used the NIF as the set.

[Rorschach]

You must pay your shrink heaps to fix your aggressive attitude towards everything... personally I think you are wasting your money...

You can relax Chard...nobody is saying it's just around the corner... so take a big breath, count to 10 and try to relax.

[Chard]

Dude, when I was a kid I was promised robot house cleaners and jet packs by the early 2000s. We're now into the second decade of this century and I still don't have my robot maid or my goddamn jetpack.

Point is, I can't stand wannabe science writers attempting to play futurist by over-hyping every single technological breakthrough as if it were heralding the dawn of a new era for all mankind. Simple fact is, as long as fusion research has been going on (seriously, the human race has been at this for over half a century now with not much progress outside of weapons applications), and as little progress has been made I seriously doubt I'll see fusion as a power generation source in my lifetime. Seriously, is it to much to ask journalists to report just the facts and to stop the hyperbole?