Tuesday, April 10, 2012

Why Our Houses Aren't Solar Powered

Man has come to the brink of mastering the forces of nature in his short time on this planet. We have managed to outrun the fastest animals, create a global economy and even touch the heavens, but it has come at a cost. The entire world is now facing a serious problem: global warming. Our heavy use of fossil fuels has released more carbon into the atmosphere than we'd like to imagine, and it's having an effect on our world. We know it's time to change, so why haven't we?
Maybe a bit dramatic, but you get the point.
The technology for a sustainable energy economy exists today, that's not what's holding us back. What's holding us back is the implementation of these technologies. Many of them are expensive or would require an entirely new infrastructure to sustain. Take the electric car for example, they're possible, in fact, we've already built them, so why aren't we all driving them? One reason is that they are still fairly expensive, but that's not a good excuse. We've had the technology for a very long time, but an electric car hasn't been on the market until very recently. So, if cost isn't a good reason not to have them, what is? I'll tell you, it's infrastructure. We just don't have what we need for everyone to drive an electric car. Electric cars need electricity, so they need to be charged, the only problem is that our gas stations serve us gas, not electricity. For electric cars to become widely used, electricity will need to be more widely available for the average Joe on the go. This could mean special outlets at every gas station or very efficient solar panels on the roof, who knows. The one thing that we can know, however, is that we need some way to power a lot of cars if everyone is going to start driving them.
A Reva electric car charging
Now let's get right down to the main point. Energy efficient devices like cars are fun and all, but the real meat in the solution to our energy problem lies with replacing the current infrastructure with renewable resources. Your lights, computer, refrigerator, almost everything you own is powered by some large facility somewhere, whether it be coal, oil or nuclear power. The ultimate goal is to replace these facilities with renewable energies ranging from wind to solar energy.
Wind is one of the better renewable resources out there. The facilities to gain energy from it don't produce much waste at all, and they are relatively harmless. They're not perfect, however. Large wind turbines are unsightly and can be very noisy, which means that people don't want them around their houses. Whenever a new one is installed, the locals believe that it will make their property values drop, and so they resist it. Then there is also the misconception that wind energy is land intensive. While those giant turbines may be tall, they aren't very wide. For some reason, a lot of people believe that you have to have empty land beneath a windmill, but this isn't the case. Wind turbines are perfect for farmlands, you can grow your crops right up to their bases without fear of interfering with the machines function. Problems do arise when people talk of clearing out forests to build more, however. Another real concern, a big concern, is the effect of windmills on the environment. It turns out that birds and bats get killed at an alarming rate in the wings of these giant machines. This becomes and even bigger problem when those animals dying are endangered, which they all too often are.
Arrays of wind turbines collect energy from nature
Another favorite renewable energy is hydroelectric power. The basic premise is that a large turbine is turned by the natural flow of water on the earth. While it may sound good on the surface, hydroelectric power turns out to be one of the worst forms of renewable energy. The biggest energy producers for this field are dams, like the famous Hoover Dam, that control water flow to create power, but the U.S. has run out of places to put new dams. Even beyond the lack of potential for new dams, the existing dams mess with wildlife. Fish that have to travel downstream, like salmon, often get caught in the blades of a water turbine and are killed. With the lack of potential for big hydroelectric producers smaller solutions were sought out. The problem of the wildlife interruption still remained, however, and smaller hydroelectric plants just weren't very effective. So far hydroelectric power hasn't turned out well.
 Hoover Dam
Another great idea for renewable energy comes from deep inside the earth itself. The inside of our planet is very hot from massive pressures and residual heat from the accretion of our planet, and this heat can be harnessed. Current technologies allow us to bring up heated water or steam from below the ground and use it to boil water and turn large turbines. Currently new technologies that would allow us to use heat from dry rock, pressurized brine mixed with methane and even magma are being developed, but for now, let's just focus on what we have. Geothermal is a great way to get power, it's entirely renewable and is capable of generating a lot of energy. There's just one problem, it's toxic. As the ground water is brought up through the earth's surface it leeches many toxic minerals and gases from the ground around it. Now, before I continue I should explain, there are actually two methods for getting geothermal power, closed-loop and open-loop. Closed-loop simply means that the water taken from below the earth is returned after it has been used, while open-loop means that it isn't. In closed-loop systems, there isn't really any problem from the toxic water because it is never released. The problem comes from open-loop systems. Toxic chemicals can be spewed into the atmosphere or condensed into a poisonous sludge. You may be wondering the, why we don't just all use closed-loop systems? I'll tell you: closed-loop systems are a bit more expensive.
  Closed-loop geothermal plant
Finally, let me touch on solar energy. Our sun puts out far more energy than we need to run the entire world each day, but it is underutilized. That giant ball of hydrogen will probably last another 5 billion years, more than enough time for us to get off this tiny rock, but only if we start using what it has to offer. So far we have developed two ways of using the power of the sun, the first is with photovoltaic cells that will generate a current when light is shone directly on them, and the second is giant arrays of reflective panels that use the light of the sun to boil water and turn a turbine. Both methods are expensive, but they are not equal. The water boiling technique requires a lot of land and water for cooling while the photo-cells can go almost anywhere and don't need any cooling. Currently, however, neither of them are very cost effective, but the technology is still being developed. Already other countries besides the US have found ways to use them, so it's time that we stepped up the game.
A photovoltaic array

 Utility-scale solar power plant

Sunday, April 1, 2012

Hypergiant Stars

Stars are big, monumentally and inconceivably big. Our sun alone could fit 1,300,000 Earths inside of it, and I dare you to try to comprehend the size of the Earth alone. Now just think, our sun is relatively small. All throughout the universe exist stars that put our sun to shame. The largest and most intimidating of these stars are known as hypergiants.
Our planet is puny compared to our sun.

 Being from planet Earth and all, it's only natural that we should use our experiences as a baseline for what we observe beyond our solar system. For example, 1 sol is a unit of comparison to our sun (where 1 sol = 1 Earth's sun). I will be using this comparison to give you an idea of the size of hypergiants, I find it to be useful. 
I suppose it's time that I told you just how big hypergiants really are. A hypergiant star can get up to 100-265 solar masses, which means that they can easily have diameters over 1,000 times that of the sun. That's big. The closest yellow hypergiant yet identified is in the "fried egg nebula", it's diameter  would almost reach Jupiter if it were placed where our sun is now.
The Fired Egg nebula is actually two shells of debris surrounding a central yellow hypergiant.

There's an old saying, "the bigger you are, the harder you fall". This has never been more true than it is for hypergiants. Being so massive, the rate at which they burn through their fuel is amazing. Hypergiants can reach temperatures up to 50,000 Kelvin and output millions of solar luminosities (amount of light given off by the sun). All this means that hypergiants are relatively short lived stars, they may only live for a couple million years max, whereas our sun will live to the ripe old age of 5 or 6 billion years old. 
When stars die, they often go nova, expelling their outer shells as they collapse in on themselves. As you might have guessed, hypergiants go hypernova. The death of a hypergiant star is one of the most powerful forces in the universe, with the power of over 100 supernovae. To give some perspective, Eta Carinae, the hypergiant star 75,000 light-years away, will give off enough light to read by at night when it goes nova.
Eta Carinae

By now it's only natural to be wondering how big stars can get. I often wonder that myself. So far, the largest star ever observed by man is VY Canis Majoris, weighing in at 15-25 solar masses. During it's main sequence, it may even have had a mass of 30-40 solar masses. VY Canis Majoris is by far not the heaviest star out there, but it has a radius of somewhere between 1,800 and 2,100 solar radii. It is certainly the largest.
VY Canis Majoris, not the heaviest, but certainly the largest.

The heaviest star known to man is R136a1, weighing in at a whopping 265 solar masses. This star also holds the record of the most luminous, being over 8,700,000 times as bright as the sun. I'm going blind by just thinking about it.
 R136a1 seen in the R136 super cluster within the Large Magellanic Cloud.

The universe is a big place filled with big things. Objects like hypergiant stars really put things into perspective, and I'm betting that we find even bigger stars in the years to come.