Scientists have simulated time travel with photons.

http://www.iflscience.com/physics/sc...travel-photons
[Reply]

Because science says it wont work.



[Reply]

:-)


I would like to see a 50 ton semi drive over a solar roadway.
[Reply]

[Reply]

50 tons? 20,000lbs overweight. That would be a helluva fine. :-)
[Reply]

Is there a summary lying around? Preferably one that can be read in less time than Dominos can get me a pizza?
[Reply]

Life Cycles of Stars

A star's life cycle is determined by its mass. The larger its mass, the shorter its life cycle. A star's mass is determined by the amount of matter that is available in its nebula, the giant cloud of gas and dust from which it was born. Over time, the hydrogen gas in the nebula is pulled together by gravity and it begins to spin. As the gas spins faster, it heats up and becomes as a protostar. Eventually the temperature reaches 15,000,000 degrees and nuclear fusion occurs in the cloud's core. The cloud begins to glow brightly, contracts a little, and becomes stable. It is now a main sequence star and will remain in this stage, shining for millions to billions of years to come. This is the stage our Sun is at right now.

As the main sequence star glows, hydrogen in its core is converted into helium by nuclear fusion. When the hydrogen supply in the core begins to run out, and the star is no longer generating heat by nuclear fusion, the core becomes unstable and contracts. The outer shell of the star, which is still mostly hydrogen, starts to expand. As it expands, it cools and glows red. The star has now reached the red giant phase. It is red because it is cooler than it was in the main sequence star stage and it is a giant because the outer shell has expanded outward. In the core of the red giant, helium fuses into carbon. All stars evolve the same way up to the red giant phase. The amount of mass a star has determines which of the following life cycle paths it will take from there.

The illustration above compares the different evolutionary paths low-mass stars (like our Sun) and high-mass stars take after the red giant phase. For low-mass stars (left hand side), after the helium has fused into carbon, the core collapses again. As the core collapses, the outer layers of the star are expelled. A planetary nebula is formed by the outer layers. The core remains as a white dwarf and eventually cools to become a black dwarf.

On the right of the illustration is the life cycle of a massive star (10 times or more the size of our Sun). Like low-mass stars, high-mass stars are born in nebulae and evolve and live in the Main Sequence. However, their life cycles start to differ after the red giant phase. A massive star will undergo a supernova explosion. If the remnant of the explosion is 1.4 to about 3 times as massive as our Sun, it will become a neutron star. The core of a massive star that has more than roughly 3 times the mass of our Sun after the explosion will do something quite different. The force of gravity overcomes the nuclear forces which keep protons and neutrons from combining. The core is thus swallowed by its own gravity. It has now become a black hole which readily attracts any matter and energy that comes near it. What happens between the red giant phase and the supernova explosion is described below.

From Red Giant to Supernova: The Evolutionary Path of High Mass Stars

Once stars that are 5 times or more massive than our Sun reach the red giant phase, their core temperature increases as carbon atoms are formed from the fusion of helium atoms. Gravity continues to pull carbon atoms together as the temperature increases and additional fusion processes proceed, forming oxygen, nitrogen, and eventually iron.

When the core contains essentially just iron, fusion in the core ceases. This is because iron is the most compact and stable of all the elements. It takes more energy to break up the iron nucleus than that of any other element. Creating heavier elements through fusing of iron thus requires an input of energy rather than the release of energy. Since energy is no longer being radiated from the core, in less than a second, the star begins the final phase of gravitational collapse. The core temperature rises to over 100 billion degrees as the iron atoms are crushed together. The repulsive force between the nuclei overcomes the force of gravity, and the core recoils out from the heart of the star in a shock wave, which we see as a supernova explosion.

As the shock encounters material in the star's outer layers, the material is heated, fusing to form new elements and radioactive isotopes. While many of the more common elements are made through nuclear fusion in the cores of stars, it takes the unstable conditions of the supernova explosion to form many of the heavier elements. The shock wave propels this material out into space. The material that is exploded away from the star is now known as a supernova remnant.

The hot material, the radioactive isotopes, as well as the leftover core of the exploded star, produce X-rays and gamma-rays.
[Reply]

[Reply]

I find this pretty fascinating. See the biggest red box on the pic? That's all the land we'd need to dedicate to solar arrays to power the entire world for a year.

Keep this in perspective though.... It would necessitate a great deal of infrastructure that currently doesn't exist. Energy storage and conversion issues would be tremendous.

But still.... We have a giant star nearby that's constantly throwing energy our direction. Tremendous amounts, more than we'd ever need. All we have to do is dedicate the resources to harness it. Right now, energy corporations are doing everything they can to continue our dependence on fossil fuels. But this is possible. I don't think most people realize how possible it really is...

How Much Room Do We Need To Supply The Entire World With Solar Electricity?



In 2009, the total global electricity consumption was 20,279,640 GWh. The sun creates more energy than that in one hour. The tricky part is collecting that energy and converting it into useful electricity with solar panels. How much area would need to be covered with solar panels in order to capture enough energy to meet global demand? Actually, it’s not as much as you’d think.

The image above has three red boxes showing what area would need to be covered for Germany (De), Europe (EU-25), and the entire world.

So what the hell are we waiting for? Let’s start getting more solar panels on some rooftops and start chipping away at those boxes!
[Reply]

Here's some proof of what's possible with solar power....

Germany Now Produces Half Of Its Energy Using Solar



Germany has set a new record, with solar power providing 50.6% of its electricity in the middle of the day on Monday June 9th. Solar production peaked that day at 23.1GW. Three days earlier it was 24.2GW between 1 and 2pm, but on the 9th demand was down for a public holiday, allowing the breaking of the psychological 50% barrier.

Reporting of the achievement has been quite inaccurate in some cases. Coverage has often confused electricity demand with total energy consumption, which properly includes heating and industrial uses of natural gas, although these would have been low on a warm public holiday. Headlines have often implied that the 50% threshold was exceeded for over a fortnight, rather than a single hour.

Nevertheless, the scale of the achievement is considerable. Germany is not a sunny place. Indeed more than 90% of the world's population lives in countries with substantially more sunlight.

Consequently, it is wind, rather than solar, that has been the backbone of Germany's Energiewende, the transition to renewable, non-polluting sources of power.

The shift to solar energy in Germany has not come cheap, with €16 billion of subsidies in 2013. However, by creating a level of demand that spurred mass manufacturing, Germany has played a large part in bringing the cost of solar panels down by 80% in five years, allowing other countries to follow in its footsteps for a fraction of the price, particularly those with more sunlight.

Moreover, where the initial stages of the move to wind were driven by government subsidies, solar power in Germany can now compete with fossil fuels on price alone, and continues to expand, albeit at a slower rate than a few years ago.

German solar production is up 34% compared to the same time last year as a result of both better weather and increased installations. While the first is unpredictable, increasing quantities of panels ensure that the 50% record will be breached again, probably this year.
[Reply]

Yeah, those two sentences in the same story allow me to see what an unbiased, fact-based article we're being shown...

:-)
[Reply]

I'm pretty excited about the future of sustainable energy sources.

Whether it's not currently cost effective or if big energy and oil companies are keeping the programs under wraps, there will come a time when we have to move away from fossil fuels.

Bring that day on, bitches!
[Reply]

Those are my words, dummy. If you actually read it you probably would have picked that up. And if you don't think that fossil fuel corporations try and continue dependence on their product and discourage alternative energy production, then you're not paying much attention.
[Reply]

Bob Dole has been looking at solar options for his place in Red Hill. Damned batteries are expensive.


[Reply]

I pay attention. What are you saying they do to try to discourage the use of one of their products?
[Reply]