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March 16, 2012 / noelynn

The Simple Explanation

Did you know  that the fastest speed any moving object can attain in the universe is that of the speed of light? Did you know also that regardless of motion relativity, the speed of light is constant value?

Brian Greene, attempts to simplify the scientific explanation of the speed of light. He starts off with simple background knowledge. It is basic that time and distance are fundamental quantities that define what the speed is. Then he illustrated the concept of special relativity using  imaginations of three simple activities as examples. These are:

  1. Baseball catching game between two friends. The speed of the ball in relation to each friend standing is 20 feet per second.
  2. The ball became a granade after an electric storm. Friend A who was ready to catch had to run for hislife at speed 12 feet per second, after realizing Friend B was tossing a granade instead of a ball. Then the speed of the approaching granade would be (20 – 12 =) 8 feet per second. So because Friend A is running it appears that the granade speed is less than 20 feet per second.
  3. The avalanches experience. Here as the snow rumbles toward you, your inclination is to turn and run away from it. This will cause the speed of the approaching snow to decrease. So a by-stander would perceive the snow speed to be greater than that perceive by the person fleeing for life.

Through these examples, comparisons to light was  drawn. Greene, draws an imagination of a light beam as tiny ” bundles or packets” known as photons. So from example 2- Friend B now flashes a beam of laser toward Friend A. Using appropriate measuring equipment – the speed of the approaching photons would be 670 million miles per hour. So the ball, granade and avalanche represented the photons.

Apart from these illustrations, Greene concluded and backed up his explanation of the concept of speed of light with acknowledgements from three early scientists. Namely:

  1. Maxwell dating back as early as 1800’s whose work on electromagnetic theory of light, slowly convinced the scientific community. He concluded that, as a body is slowing down, the speed of the approaching photons is still 670 miles per hour.
  2. Dutch physicist, William de Sitter whose work based on fast-moving binary stars. After decades of various experiments, it was verified that the speed of light received from a moving star was the same as that of a stationary star,which was 670 million miles per hour.
  3. Einstein, the most recent famous physicist embraced the constancy of the speed of light. He concluded that the speed of light cannot be any less than 670 million miles per hour, even if it slows down to a point of appearing stationary.

Therefore, the speed of light is a contant value of 670 million miles per hour. The physicists would be of interest and familiar with this value.

So could you explain any simpler than Greene’s attempt?



Leave a Comment
  1. axl1228 / Mar 17 2012 10:26 am

    Interesting article.
    Sometimes we think simplifying equals to short paragraphs, clear graphs, but Greene sets us a completely different, better example. Long paragraphs describing examples, gives interesting and evocative images of how light travel, both hypothetical and in fact. That makes the abstract concept of light much easier to understand, especially for kids.
    Serious theories are not presented in every detail. Just the most discussed point were explained with simple examples and non-jargon words.
    It’s really different with my thought about simplifying. We often say ‘less is more’, but ‘more’ also could be ‘simple’, right?

  2. thiarayoanita69 / Mar 17 2012 1:50 pm

    Your blog has a really neat structure. The whole story flows, yet you managed to write each main point in a different paragraph. I like how you end your post with an open-ended question. This portrays that you are communicating to the readers.. I just have one suggestion, maybe it would be better if you shorten the question at the beginning?

    Regarding the article itself, I pretty much agree with what you have said. Greene has started with a general background. This is supported by real-life events, which make it much easier to relate. One more technique that I notice is that, he avoids using jargon when he can. This makes the article educative yet understandable.

  3. shortfletch / Mar 17 2012 2:42 pm

    Great post.

    I agree with axl1228. It’s very good to realize that less is not always more. What I really like about Greene’s explanation is that he stars explaining the theory of relativity using three everyday-ish examples (okay so I don’t play catch with grenades) instead of light. I know what a ball is. I have younger brothers who like to chuck them at my face. Therefore, I have run away from baseballs. I can remember and relate to this explanation. I have more trouble understanding and relating to light.

    I also likes how he builds the explanation up slowly. We start with stationary people tossing a ball. He explains the speed of the ball (20 ft/s) is *relative* to the people standing. Okay, so now I understand that speed is relative.

    Next, one person starts running. The speed of the grenade is still relative to the people. However, because the people are moving at different speeds from the ground, the relative speed of the grenade is different for each person. (I probably would have stuck with the ball not grenade because it makes it more straight forward in my opinion). Now I realize that speed that a person is traveling also affects relativity, and reinforces the fact that relativity can mean things are different for different people. Form this part of the example I start thinking about cars. How if a car drives by you when you are walking it seems much faster, then if you were biking (I don’t know why I think of cars but I do).

    For me the third example (avalanche) works to reinforce the earlier examples. I think this is good incase you didn’t really understand the first example.

    The step by step building keeps me from getting lost or overwhelmed. This is why I like it.

  4. baileymoser / Mar 18 2012 2:53 am

    I myself watched Brian Greene’s series about the cosmos on PBS this past year and thought it–like this excerpt from his book–was an excellent example of simplifying science for the non-scientist.

    I don’t think this excerpt from his book touches much on what you said at the very end: “The physicists would be of interest and familiar with this value,” however. Why? Brian Greene doesn’t really tell us here, and to any physicist, this passage would seem mildly redundant and uninformative. Why did “Einstein [realize] that the constancy of light’s speed spelled the downfall of Newtonian physics”?

    Yet if he were to touch on these topics, would his work lose attainability for the non-scientist? I think this blog and excerpt also help support why consideration of your target audience is key to simplification.

  5. fullclever / Mar 19 2012 9:37 am

    The article was written in a creative way. The difference between the work of Brian Greene and the common physical books (full of formulas and diagrams) and notorious. The excerpt in question is so simple and with a language so current that facilitates fluent reading. Still, it respects the basic rules of academic writing.
    Unlike some of the opinions above the text of this Greene summarized. Who had read this book (at least in the first edition) knows that by having the relevant information in excess, the author or editor was forced to create a wide endnote for those who are interested to read further.
    The argumentation of Noelynn could be richer. After brief comments she filled the article with ideas of Greene and then left an open question.

  6. lindsayd20374453 / Mar 20 2012 4:20 am

    I agree that simple explanation through analogy is one of the msot effective tools in science communication. Greene’s article certainly seems to be a good example of an abstract concept, explained in a simple manner. It’s particularly important to have an explanation for the speed of light and relativity handy in your mind at all times as a science communicator, as I’ve found this is one of the most common questions that curious people will ask (consider the old ‘if I’m in a spaceship moving at the speed of light and I run forward etc etc).
    One issue that analogous explanations can have, is that they risk becoming bogged down as the situation becomes more complex. I’ve read many explanations which end with something like “And so the baseball is a photon, the person is an atom, the dog is the sun, the sun is a dog, and the avalanche doesn’t exist”. I think for that reason it’s important to stop the reader at various points to consolidate the knowledge that’s been explained so far (think “and this whole concept is called relativity. Now, applying relativity…”), before moving on to other topics.
    As far as simple explanations go, one of the best sources I’ve found are the ‘Explain Like I’m Five’ and ‘AskScience’ sections of a social aggregator site called Reddit. Basically, the site works by people asking questions, which are then voted up or down by users. This determines how visible the questions are. The questions are then answered by other users, with a similar ‘voting’ system. The crux of ‘Explain Like I’m Five’ is that complex concepts get boiled down to simple analogies and descriptions, such that they could be understood by an (imaginary) five year old. I’ve seen some excellent explanations of complex scientific and non-scientific issues on that site. AskScience performs a similar role, but in my opinion does a better job with more complex concepts, with more sophisticated explanations. After all, science is pretty complicated a lot of the time, and one’s always got to be careful of oversimplifying issues. Either way, I feel that both sections are very useful to science communicators, and it’s a site I spend a lot of time reading and contributing to. You might find it interesting.
    Here’s a link to a collection of some of the best ELI5 answers (note: while this section of reddit is completely worksafe and fine, some of the other sections of the site are not. Use your common sense.):

  7. annagardiner / Mar 22 2012 12:02 am

    I actually really enjoyed your post, I thought it was going to be boring because most things I read about physics are so full of jargon I just give up. Greene has been so skillful at watering it all down and presenting it in a way that everyday people can understand and then in turn you’ve done a great job at representing those simple explanations here.

    Chunking the information into dot points made it super easy reading and you were great at writing straight to the point! I do agree with baileymoser about the ending though; I thought that it was something that would be of interest to the general public more than physicists. Another summary sentence to really wrap it all up would have made for a punchier ending.

    Banging post in all though, I learnt stuff which is fun – so thankyou!

  8. lodoubt / Mar 22 2012 4:58 am

    I’m going to be the minority report here by not looking at Greene’s article first and just reading yours. It seems unfair but I figured it would provide a different perspective.

    It seems to an extent as though you didn’t quite finish your explanation of Greene’s techniques used in explaining special relativity. You described a series of scenarios which describe ‘normal’ relativity, with the implication this was leading up to special relativity, and introduced the replacement of those objects with light, but you didn’t follow on to explain the effect that would have. Whilst I would have eventually picked up on what special relativity was, if I hadn’t known it already (and yes, as a target audience most of us probably do), it seems as though the part of your article that was meant to explain this in relative detail by summarising how Greene did so… didn’t. That leads me to wonder whether that section of your article served any purpose within your review.

    From the sound of your article, it seems as though Greene is excellent at the “science told as a story” style techniques we’ve been examining so much in lectures recently; so ultimately you’ve succeeded in communicating that. It was just some of the background that I felt was a bit weak.

  9. chimk / Mar 22 2012 7:56 am

    the article was well written and it was simplied. The good thing about this article is Greene used practical example of baseball to try to explain speed of light. The blog is well written, the paragraphs are flowing nicely and the opening statement is catchy while the ending is trying to make the readers think, its actually enganging.

  10. JamieAlexandraGraves / Mar 22 2012 1:20 pm

    Hi noelynn,
    I think your blog is a very accurate summary of the article “the elegant universe” by Brian Greene. I agree with the points raised by axl1228 and shortfletch about their ideas on simplicity in writing. I have always been a supporter of “less is more” but this article has definitely made me think twice.
    One thing that definitely kept me focused on the article however was Greene’s use of quirky examples in his writing. These made the abstract quite humorous and light-hearted, and kept me from feeling overwhelmed when faced with the complex notion of the relativity of light. I personally would have focussed a little more in this area in your blog.
    Otherwise, I liked your clear, structured writing style and focus on the simple examples used in the article, which makes it relatable and relevant – a very simple explanation! ☺

  11. dcastledine / Mar 22 2012 1:37 pm

    I really like this post!

    As a Physicist I am of course interested in any blog post that involves the speed of light however that’s not why I liked this post. The reason I enjoyed this post was because you started the whole thing with questions that I continued to think about while reading and then you tied the whole thing back together with another question at the very end.

    I am not a huge fan of the actual article from a physicist’s point of view however I really did enjoy the way that this blog post boils down the article into something that is simple to read and understand for anyone.

    • noelynn / Apr 24 2012 3:26 am

      Thank you for your comment.

  12. markforeman92 / Mar 22 2012 2:50 pm

    For a topic that can be extremely complicated, i found that Brian Green’s article was pretty succinct and understandable. I thought your blog provided a good summary as well! I am a big fan of analogies, and using the baseball/avalanche adaptations were effective in my opinion and, not having studied physics, helped me understand and visualise the idea of relativity.

    I didn’t understand the final aspect of your post though. As it is established that the speed of light is 670 million miles per hour, you said “The physicists would be of interest and familiar with this value”. As i said, i haven’t studied physics so that won’t help, but is Einstein’s conclusions contrary to popular physicists beliefs? Perhaps you could have explained that better, and perhaps Brian Greene could have explained that better but he may have done so in a later chapter, in which case it’s not such an issue!

    But as a physics dummy, i found your post effective and easy for somebody like me to follow! So good job! And for such a complex issue, i agree with previous posts that Brian Greene was reasonably effective at communicating this scientific issue. Good Job!

  13. shannonjane93 / Mar 22 2012 4:01 pm

    I like the way you’ve written the post, and the layout is really nice too! Having dot points and breaking down the structure makes the physics very readable. I would question the lack of background, and am somewhat confused as to what the subject of the article was supposed to be; the speed of light, or Brian Greene? And so far as analogies go, I’ve always found the train one easier for understanding- Brian’s one involves too many scenarios for my head to easily envisage.
    But your writing style is nice and fluid, good job!

  14. noelynn / Mar 22 2012 10:59 pm

    Thank you for all the comments. Lindsay, the links were helpful. I know there’s still a lot of room for improvement in this post.
    To be frank, this is the first of its kind in my academic life to be peered oriented. I sure have learnt a lot, not only to be exposed this way, but also to experience the conscious processing hypothesis.

    Hope to do better in other posts.

  15. amess02 / Mar 23 2012 12:28 am

    I really enjoyed this post, using analogy as a means of relaying a difficult concept is one of the greatest ways to learn, in my opinion. I really liked how you engaged the audience by asking if there was a better version of Greene’s attempt out there. Simplifying concepts, though helpful in understanding can sometimes confuse, the first analogy with the ball did leave me a bit puzzled. Oversimplifying can be a problem so at what point does the concept become moot because the analogy is just too simple? Well done on a good first peer-oriented piece!

  16. mario93 / Mar 23 2012 11:05 am

    I liked the way you’ve structured your post, by chunking the information you’ve made the main points very clear. This is a great summary of Brian Greene’s article.

    This blog as well as the article has made the concept of the relativity of light, which can be very confusing, much more simplified and easy for everyone to understand by the used of relatable examples.

    I loved the thought provoking questions that started off the summary and how it tied it all up at the end, leaving the reader with something to think about.
    Great post!

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