The Universe and diseconomies of scale – a consequence of expansion.
To summarize a cafe discussion on dark energy seems almost like a Sisyphean task, not only because of the burden of what is still unknown about the topic, but also the complexity of what is known. Professor Nikhil Padmanabhan ignited the interest of those attending this most recent Tilde Cafe discussion. He shed light on the topic quite effortlessly and gave us some appreciation of the magnitude of the questions he and his peers are attempting to answer through their research efforts. That the Universe was expanding was known for almost a century, but it has been only in the last two decades that there has been evidence of an acceleration of this expansion. And this new evidence comes from the field of dark energy. Although the term “dark energy” was coined only in 1998 as a consequence of then puzzling results, the 2011 Nobel Prize in Physics went to three scientists who “helped to unveil a Universe that to a large extent is unknown to science.” Dark energy constitutes about 70%of the Universe; dark matter – 25%; we constitute barely 0.03%! Perhaps one aspect that makes it harder for those of us who aren’t devoted to studying dark energy appreciate the field, is the fact that while there is evidence of the existence of dark energy, it’s composition remains largely unknown. After introducing us to some basic concepts, Nikhil described what goes into a typical survey of the skies, right from collecting images, to how spectra are collected from the objects observed – check the video from the afternoon at – http://www.youtube.com/watch?v=xGxU1uRCx1I&feature=youtu.be (55 min mark). Despite the relative opaqueness of the topic, we had almost twice the number of people than we’d expected, which is always welcome and a treat, so thank you all for coming out on a lovely Saturday afternoon. This was the first cafe discussion for many, and I hope it has helped to whet their appetites – watch this space for many more engaging discussions. From the press release by the The Royal Swedish Academy of Sciences – “…..dark energy [is] remains an enigma – perhaps the greatest in physics today”, and Nikhil helped us get a peek at that enigma on Saturday afternoon. Thank you, Nikhil.