February Post: Gravitational Waves Might Not Exist?

This month, I found a very interesting article that argued that gravitational waves might not exist after all. If this is true, then my senior project would be greatly affected. Fortunately, this is not concrete evidence to prove that gravitational waves don't exist. However, it did still give me a new and fresh perspective on my esoteric topic. The link is below:

http://phys.org/news/2015-01-planck-gravitational-elusive.html

Essentially the article states:

Despite earlier reports of a possible detection, a joint analysis of data from ESA's Planck satellite and the ground-based BICEP2 and Keck Array experiments has found no conclusive evidence of primordial gravitational waves. "While we haven't found strong evidence of a signal from primordial gravitational waves in the best observations of CMB polarisation that are currently available, this by no means rules out inflation," says Reno Mandolesi, principal investigator of the LFI instrument on Planck at University of Ferrara, Italy.

Blog 16: Answer 2

1.)  What is your EQ?

- My EQ is "What is the best solution for detecting gravitational waves?"
2.)  What is your first answer? (In complete thesis statement format)

- Interferometers could detect gravitational waves with the usage of laser to see changes in space-time.
3.)  What is your second answer? (In complete thesis statement format)

- Pulsar Timing Arrays could detect gravitational waves with their perturbation-seeking-sensors through pulsars.
4.)  List three reasons your answer is true with a real-world application for each.

• The signal from a pulsar can be detected by radio telescopes as a series of regularly spaced pulses, essentially like the ticks of a clock.
• Gravitational waves affect the time it takes the pulses to travel from the pulsar to a telescope on Earth.
• A pulsar timing array uses millisecond pulsars to seek out perturbations due to gravitational waves in measurements of pulse arrival times at a telescope, in other words, to look for deviations in the clock ticks.

5.)  What printed source best supports your answer?

- Feynman, Richard P. QED: The Strange Theory of Light and Matter. Princeton, NJ: Princeton UP, 1985. Print.

6.)  What other source supports your answer?

- Moskowitz, Clara. "Dark Matter Black Holes Could Be Destroying Stars at the Milky Way's Center." Scientific American Global RSS. Scientific American, 10 Nov. 2014. Web. 12 Dec. 2014.
7.)  Tie this together with a concluding thought.

- My new answer differs from the 1st because pulsar timing arrays would scan the universe's space-time instead of looking directly at the waves, like a inteferometer does.

Blog 15: Independent Component 2 Approval

1.)  Describe in detail what you plan to do for your 30 hours.

- For my independent component 2, I do not have any concrete plans, but one thing I have looked at that could strengthen my answers to my EQ would be Gravitational Wave Interference. They are most connected to my answer 2, but they could also help me see what scientists try to do when observing gravitational waves. I would try to construct one then test around with it.

2.)  Discuss how or what you will do to meet the expectation of showing 30 hours of evidence.

- As I create and test the interference, I would log every detail in my hours log. I will narrate the step by step process and also include lots of pictures.

3.)  Explain how this component will help you explore your topic in more depth.

- This component is essentially my answer 2 and this would help me understand how gravitational waves were detected before the advent of interferometers. As I create the double-slit experiment, I would understand how scientists construct various apparatus, and this would nice to include in my final presentation.

4.)  Post a log in your Senior Project Hours link and label it "Independent Component 2" log.
- Done.

Blog 14: Independent Component 1

LITERAL

(a) Write: “I, Denesh Chandrahasan, affirm that I completed my independent component which represents 30 hours 15 minutes of work.”

(b) Cite your source regarding who or what article or book helped you complete the independent component.

- My most important sources in helping me do this component were:

1. Feynman, Richard P. QED: The Strange Theory of Light and Matter. Princeton, NJ: Princeton UP, 1985. Print.
2. Giancoli, Douglas C. "General Relavitity: Gravity and the Curvature of Space." Physics; Principles with Applications. 6th ed. Upper Saddle River: Pearson Education, 2005. 926-29. Print.
3. Stannard, Russell. "Gravitational Waves." Relativity: A Very Short Introduction. Oxford: Oxford UP, 2008. 95-99. Print.

The 1st source helped me by giving me a strong foundation in how exactly light works in relation to reflection and wavelengths. The 2nd provided the mathematical side of what I was doing, and the last one was directly explaining how interferometry helps detect gravitational waves.

              
(c) Update your hours in your Senior Project Hours link. Make sure it is clearly labeled with hours for individual sessions as well as total hours.

- Done.

(d) Explain what you completed.    

- Essentially, what I created and assembled is called an interferometer. I made a home-made one by buying the parts online (don't worry I bought them for reasonable/cheap prices). I put the parts together by arranging the mirrors on the base so that a laser could bounce off the mirrors in such a way that it came back to the original spot. (Read my Senior Project hours Log for the details).

INTERPRETIVE 

Defend your work and explain its significance to your project and how it demonstrates 30 hours of work.   Provide evidence (photos, transcript, art work, videos, etc) of the 30 hours of work.  

- The interferometer is extremely significant to my project since it is literally my first answer to my EQ (What is the best solution for detecting gravitational waves?). A sensitive detector uses laser interferometry to measure gravitational-wave induced motion between separated 'free' masses.This allows the masses to be separated by large distances (increasing the signal size); a further advantage is that it is sensitive to a wide range of frequencies. 

This demonstrates 30 hours of work since I prepared for the construction, ordered the parts, studied videos and models online, actually physically built the apparatus, then tested it. 

Pictures

These are the parts I actually had to order online. There are the 2 fixed mirrors and 1 adjustable mirror. At the bottom is the laser diode. Don't worry - they were cheap!

My first attempt at attaching the parts to the base of thick cardboard covered with paper. (It later fell apart)

My second attempt at reattaching the parts. If you look closely you can see the extra layer of adhesive I used.

This strange mark is actually the interference pattern generated by the two rays, and it is an incredibly finicky thing to establish - expect a good half hour of gently poking and tilting the elements till you glimpse this faint but unmistakable banding.

That is being projected onto an almost-horizontal piece of white card. I tilted the card so that the interference pattern would be broadened out and the fringe motion would be more readily observed.

APPLIED

How did the component help you understand the foundation of your topic better?  Please include specific examples to illustrate this. 

- 

This independent component helped me understand the mysterious gravitational waves because it illustrated a real-life apparatus that scientists use to detect them. The real-life examples that are applicable are  LIGO and LISA. Currently, the most sensitive interferometer is LIGO – the Laser Interferometer Gravitational Wave Observatory. LIGO has three detectors: one in Livingston, Louisiana; the other two (in the same vacuum tubes) at the Hanford site in Richland, Washington. 

Each consists of two light storage arms which are 2 to 4 kilometers in length. These are at 90 degree angles to each other, with the light passing through 1m diameter vacuum tubes running the entire 4 kilometers. A passing gravitational wave will slightly stretch one arm as it shortens the other. This is precisely the motion to which an interferometer is most sensitive.

This component also would support our current model of Physics by proving that gravitational waves actually exist. This is something suggested by Einstein's theory of relativity, but has yet to be proven. Interferometer like I built are simple models of the big ones that can someday detect those waves when 2 black holes collide.