We talked, not long ago, about how relatively rough simulations of the largest constituents of our universe can help us understand galaxy formation and evolution, how galaxies cluster together, and many other large-scale features of the known universe. But how do computer simulations incorporate things like dark matter and dark energy—which we know must be there and accounted for in our more and more accurate models, though we don’t quite know yet what they are? How can simulations be used as models of the observable universe, and provide testable insight? And how can we simulate the mutual interactions of billions of celestial objects, each attracting each other, and clustering and orbiting in many different ways, a problem mathematically unsolvable? An interesting article in the computing science section of the January-February issue of American Scientist offers an overview of the singular challenges associated with re-creating the universe in a box, and how this whole process represents a brilliant example of the scientific method in action in the digital era.
Brian Hayes, “A Box of Universe”, American Scientist
Since the creation of the internet and a colossal worldwide growth of personal computers, there has been a gradual change in the way some scientific research is carried out. Initially, idle computing power was donated by people wishing to contribute to science projects such as Einstein@Home, in order to perform computationally demanding tasks faster. However recently scientists have become just as interested in the brain power of people around the world to help them with ongoing science problems. Galaxy Zoo and the larger suite of Zooniverse projects have successfully built the largest (nearly 0.5 million) and most popular online community of ‘citizen scientists’ who are eager to participate in scientific projects. Citizen scientists have helped classify hundreds of thousands of galaxy images taken by NASA’s Hubble Space Telescope, as well as identifying a new type of greenish compact galaxies called Green Pea’s, which computer algorithms had previously been unable to spot, highlighting a key advantage for employing this type of analysis.
The Milky Way Project is the ninth project to be contributed to by online citizen scientists, for which users are tasked with identifying bubbles of infrared emission in images taken by the Spitzer Space Telescope. These infrared bubbles are common features of regions of ionised gas and dust in the Milky Way and other galaxies that are undergoing star formation, which are of interest to astronomers. In a recent paper available on arXiv, it was shown that about 35,000 citizen scientists collectively found 5106 bubbles including at least 86% of objects already catalogued by experts, showing that the human eye and projects like this are an important tool for future astrophysics research.
Orbital angular momentum—a new tool for space science and technology. In this episode of It’s Not My Field we interview Bo Thidé, from the Swedish Institute of Space Physics, who was invited to the University of Glasgow to discuss his work. He presented his successful experimental results on radio frequency orbital angular momentum, and the possible applications to radio telescope arrays, telecommunications and medical imaging.
Visit our SoundCloud page to download the episode.
We thank Bo Thidé, the School of Physics and Astronomy and Nigel Hutchins.
The episode includes CC-licensed Freesound.org sound samples from users Setuniman, ERH and WaterminD.
Source: SoundCloud / ScientificBritain
On the International Space Station, astronaut Don Pettit uses electrically charged knitting needles and water droplets to show how in microgravity conditions the latter can orbit the former. Although the orbits of the droplets and some of the features they exhibit are similar to those of planets around a central cylindrical body, electrical—not gravitational— interactions are at work here.
Often, in high school and undergraduate physics classes, atoms are intuitively presented according to the outdated planetary model: a swarm of electrons orbiting the nucleus, like planets around the sun. The progress in the understanding of the subatomic world in the early 20th century, and the advent of quantum mechanics, made the description of atoms much more complex. There is a boundary between the world of our everyday perception and the subatomic, distinctly quantum world—where Newtonian mechanics breaks down and the laws of quantum reality rule undisturbed. This boundary, however, is hard to place. For systems of sufficiently large sizes, their quantum behaviour can be better and better approximated by Newtonian mechanics, which rather accurately describes forces and motion up to the planetary scale and beyond. By studying large enough atoms and their cloud of electrons, Rice University researchers managed to simulate the orbits of Jupiter’s Trojan asteroids, just there, at the boundary between the baffling quantum world (where subatomic particles such as electrons are more accurately described by fuzzy, delocalised wave functions) and the reality of planetary orbits.
“Rice lab mimics Jupiter’s Trojan asteroids inside a single atom”, Rice University press release
Wyker et al., “Creating and Transporting Trojan Wave Packets”, Physical Review Letters (2012)
Quantum electrodynamics (QED). In the second episode of It’s Not My Field we interviewed Thomas Philbin, a researcher at the University of St Andrews, who came to talk at a school seminar at the University of Glasgow. He discussed with us the ongoing debate regarding the theoretical foundations of the Casimir effect, a force that results from the quantum nature of the microscopic universe, as well as recent experiments and potential applications within nano-scale engineering.
Visit our SoundCloud page to download the episode.
We thank Thomas Philbin, the School of Physics and Astronomy and Nigel Hutchins.
The episode includes CC-licensed Freesound.org sound samples from user WaterminD.
Source: SoundCloud / ScientificBritain
The light-field camera is a new piece of technology that will radically change the way we can take images, and potentially video, in the future. By using a micro-lens array in the plane of the CCD sensor, and relocating the chip to a distance equal to the focal length of the lenses, it is possible to detect both the intensity and direction of the incoming light rays. This means it is possible to post-process each image captured in order to alter the plane of focus. Furthermore, this technology enables multiple perspectives via parallax from a single picture. This video helps to describe the fundamental optical physics behind the technology soon to be released. The company that has produced the first of its kind—Lytro—is a spin-off project from research by Ren Ng, who obtained a PhD at Stanford University in 2006.
The pitch drop experiment, started by Thomas Parnell of the University of Queensland in 1927, is probably the longest-running experiment of the 20th century. It was originally devised to demonstrate that pitch, a so-called viscoelastic polymer of which bitumen is a prime example, is not a solid but actually a viscous fluid. Even though it does appear solid at room temperature, and exhibits behaviours commonly associated with solids, like shattering on impact, when placed in a funnel pitch will slowly drip as if it were a very thick molasses—at an average rate of one drop every nine years. The viscosity of pitch, it has been calculated, is about 230 billion times that of water. Relegated to closets and then placed on display again only in 1975, this singular experiment can now be observed live via webcam: a scientific alternative to counting sheep.
R. Edgeworth, B. J. Dalton and T. Parnell, “The Pitch Drop Experiment”
