Wonders of the Sky!

The night sky is truly mesmerizing. I look at this quite often. Having seen the moon's craters, I now crave for a telescope strong enough to show Saturn's ring. And then I start wondering, science and technology has made observing the universe quite fun and easy (as compared to the days of  naked eye astronomy i.e. days of the ancient Greek astronomers).

 

Around 3rd century to 1st century BC (part of the Hellenistic period), a number of ancient Greek astronomers contributed to 'Astronomy', laying the initial foundations (if I may). During this very period, you do be amazed to know that 'Aristarchus of Samos' was the first Greek astronomer to propose a Heliocentric sun-earth model (i.e. in which the earth revolves around the sun)! Alas, this knowledge was lost and the Geocentric sun-earth model (i.e. in which the sun revolves around a fixed earth) prevailed for approximately the next 1800 years. 'Hipparchus', another great Greek Astronomer cum Mathematician, is credited with preparing the first star catalog during this period too. This genius used his eyes only (as there were no scientific tools then) and tried to capture all the movements in the night sky. What a feat! These men believed in the Heliocentric model, when the entire world was fixed with the Geocentric model.

 

In 2nd century AD, Claudius Ptolemy wrote many scientific treatises. One of the most famous is 'Almagest' - treatise on Mathematics and Astronomy (For more details, check out http://bertie.ccsu.edu/naturesci/Cosmology/Ptolemy.html). This is one of the most influential scientific texts of all times. Ptolemy further developed star catalogue (i.e. a version), originally created by Hipparcus.  And he advocated the Geocentric model.

 

It took nearly 1500 years for the Heliocentric model to be revived. And Nicolaus Copernicus did this in the 16th century AD. Tyco Brahe, Johannes Kelper and Galileo Galilei contributed immensely to the science of astronomy, in this century. They came up with planetary motions and accurate astronomical observations.

 

Telescope was invented in the 17th century AD and Galileo was the first to use one for celestial observations. He was kept  under house arrest for life, as he advocated the Heliocentric model. Think about this for a moment. Today, a 7-8 year kid is also taught about the planets revolving the sun. And just 2-3 centuries ago, supporting this very fact was considered a crime! We really have come a long long way since then. I believe that the advancement made by mankind in the last 200-300 years is equivalent to (or surpasses) around 2000  years' worth of advancement (prior to the 200-300 years period).

 

Today, there are excellent telescope systems that monitor the solar system and beyond. I am sure you have heard about NASA's Hubble Space Telescope (in honor of Edwin Hubble). Check out http://www.spacetelescope.org/images/archive/top100/, list of superb Hubble photos. NASA's Chandra X-Ray Observatory is another marvel. Check out http://chandra.harvard.edu/ for more information. This observatory (floating high above the earth's atmosphere) is designed to detect X-rays. These rays get absorbed by earth's atmosphere. And that is why we need an observatory floating above the earth's atmosphere, to detect them. Check out https://en.wikipedia.org/wiki/List_of_space_telescopes for a list of major telescopes put into Earth's orbit.

 

You have many options when it comes to buying a household telescope. Check out http://www.skyandtelescope.com/astronomy-equipment/choosing-astronomy-equipment/telescopes/ and http://www.skyandtelescope.com/astronomy-equipment/types-of-telescopes/ for more details. There are telescopes that can point and track the night sky objects automatically! Cool indeed. To start with, observe the moon. Do you know that we always see 1 face of the moon? We never get to see the other side of the moon. Why? Because the moon's rotation around it's own axis and it's revolution around the earth are the same. The other side of the moon (that we never see) is very different from the face that we see. Try some google searching to find out why.

 

Now, how do you decipher your local night sky? Easy! I frequently use this beautiful web resource to view the night sky at my latitude and longitude -  http://www.fourmilab.ch/yoursky/. Try it out. Know your local night sky and follow planets. Get hooked to the beautiful night sky.

 

If you are game to more than the local night sky, then check out http://live.slooh.com/. This website streams live celestial events (with scientific discussions) - meteor showers, eclipses, sun flares, comets and more. Sign up and you will get notifications before the start of such events. By the way, Sun flares (i.e. magnetic storms) create the phenomenon of the 'Northern Lights' aka 'Aurora' - on my To-Do list.

 

And if you need more, then plan a trip to the Australian outback! Pack your bags and a good DSLR camera. Learn a few photography tricks such as taking a long exposure shot. And you sure will be rewarded :) Another item for my To-Do list. They say that this part of Australia does not have light pollution i.e. light coming from manmade sources. Hence, you get a perfect clear night sky where you can watch, in awe, the milky way. Check out http://www.bing.com/images/search?q=australian+outback+night+sky&FORM=HDRSC2  and be humbled by the magnificent universe.

Nuclear energy

Hi there! I have been reading about nuclear energy for some time now. And wanted to share what I had read and digested so far. So here comes this long long post. Hope you enjoy it.

Ever wondered what will be the energy source of the future, to sustain humanity? Of course, the very same energy that powers millions of stars in our universe - Nuclear fusion!

Where do we stand today? Humanity has tamed nuclear fission since long i.e. splitting of atoms to release vast amounts of energy. And what do we get in this process? We get
• Loads of energy i.e. converted into electricity
• Loads of radioactive waste material. Different kinds of radioactive waste have different half-life i.e. time taken to decay. This could be a short span to millions of years. Nuclear fission gives us a considerable amount of radioactive waste that takes millions of years to decay! You may be asking now - where on earth, do we hide this waste? Well, this sure is a big headache. Check the following links out - https://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_repository or https://en.wikipedia.org/wiki/Waste_Isolation_Pilot_Plant.

Enter Nuclear Fusion i.e. fusing/joining two or more atoms. Is this better than fission? Of course yes! Read on
• Well to start with, Nuclear fusion releases around 3 to 4 times more energy than nuclear fission. And by the way, nuclear fusion is mother nature's preferred way of powering the universe. Nuclear fission does not normally occur in nature. No wonder fission gives us unwanted waste. We source fission with uranium or plutonium. On the other hand, Hydrogen is the most simple, basic and abundant source needed for a fusion reaction (fusion can use other light and heavy chemical elements too)
• Fusion results in very little radioactive waste (relative to nuclear fission). Moreover, this radioactive waste usually has a half-life of a few decades only
• How about safety? You have heard or read about the nuclear fission disasters at Chernobyl, or the latest one being Fukushima (triggered by a tsunami). The waste material coming from a fission plant generates huge amounts of heat and that is why such plants need some cooling mechanism. Now, if the cooling mechanism does not work for some reason, the radioactive material generates enough heat to melt the nuclear reactor (known as a meltdown). And this may lead to some serious hazards. Fusion, on the other hand does not have any such problem. It can be stopped spontaneously (read on for a simple explanation later).

So you ask further, why don't we have commercial nuclear fusion power plants? Oh, the answer here is simple. This is because scientists have not managed to tame nuclear fusion reaction to create unlimited energy :) There have been successful experiments but that is it. Scientists have successfully sustained nuclear fusion reactions for a few minutes only! A nuclear fusion reaction needs very high temperatures (tens of billions of degrees). This is like recreating the core of the Sun, on our planet. The good news is that scientists know how to achieve these unimaginable temperatures - by confining the fusion source (usually in the 'plasma' state, which is a fourth state of matter. I know, I know, we all grew up with 3 matter states - solid, liquid and gas. This fourth state is a topic for discussion on some other day). The confinement squeezes the plasma to such an extent that we achieve temperatures far greater (nearly 10 times hotter) than the Sun's core temperature . And voila, there comes our fusion reaction!

Tokamak - The most successful plasma confinement magnetic device used for experimental fusion.
Sustaining such high fusion temperatures require a lot of energy and there are technical challenges too. Imagine trying to squeeze a balloon uniformly with your bare hands. The balloon will bulge out from places with least pressure. Now you can probably appreciate the problem at hand - trying to confine a plasma uniformly. This was one of the challenges that had dogged the great scientists till this very age. This confinement is now achieved using magnetic fields with great precision. The Russians gave us a device named 'tokamak' that uses magnetic fields for confinement - refer to https://en.wikipedia.org/wiki/Tokamak for more reading on this. If the magnetic field is decreased in strength, the plasma is no longer confined and tends to expand. And expansion leads to cooling down. Hence, the fusion reaction stops immediately because of the cooling effect. So it seems to be theoretically much safer than fission plants.

Still with me? Let me summarize - humanity is still experimenting with fusion energy for commercialization (which is at-least half a century away). Fusion requires very high temperatures, which we can now produce on our planet earth. The next step is to nail down the technicalities of building a commercial nuclear fusion reactor.

The future is being molded as you read this post ITER - International Thermonuclear Experimental Reactor (https://www.iter.org/mag) - this is a global multi-cultural mega scientific project that aims to build the world's biggest tokamak (in Southern France), to produce fusion energy. And in the process, scientists will learn more about how to solve the engineering, manufacturing and industrial challenges. The aim is
"to deliver ten times the power it (i.e. ITER tokamak) consumes. From 50 MW of input power, the ITER machine is designed to produce 500 MW of fusion power—the first of all fusion experiments to produce net energy.

During its operational lifetime, ITER will test key technologies necessary for the next step: the demonstration fusion power plant that will prove that it is possible to capture fusion energy for commercial use."

Source: <https://www.iter.org/proj/itermission>

For those who are thrilled, I highly recommend visiting the ITER website. It has magazines, technical know-how and all. This will keep you busy for a long time to come. Oh by the way, this project is being executed by 7 members - European Union, China, Korea, US, Japan, Russia and India.