The word “geek” used to be a bit of insult, but to be labelled a geek these days isn’t such a bad thing after all. I think a lot of that’s due to the sheer power and pervasiveness of smartphones, software and IT — in fact, the top definition of “geek” over at Urban Dictionary is “The people you pick on in high school and wind up working for as an adult.” I also reckon the huge popularity of TV’s The Big Bang Theory has played its part in the reversal of fortune of the word, with many of us following the stories of Sheldon, Leonard and their geeky physics pals.
Walk the line: Airy meridian is marked as the “Prime Meridian of the World” (dotted line), and the modern reference meridian indicating zero longitude using GPS (solid line). (Courtesy: 2014 Google Maps, Infoterra & Bluesky)
By Tushna Commissariat
A visit to the Royal Observatory in Greenwich is incomplete without walking along the Prime Meridian of the world – the line that literally divides the east from the west – and taking some silly photos across it. But you may be disappointed to know that the actual 0° longitudinal line is nearly 100 m away, towards the east, from the plotted meridian. Indeed, your GPS would readily show you that the line actually cuts through the large park ahead of the observatory. I, for one, am impressed that the original line is off by only 100 m, considering that it was plotted in 1884. A recently published paper in the Journal of Geodesy points out that with the extreme accuracy of modern technology like GPS, which has replaced the traditional telescopic observations used to measure the Earth’s rotation, we can measure this difference. You can read more about it in this article in the Independent.
In this 2D slice of the supergalactic equatorial plane, the boundary of Laniakea is the closed orange curve. The white lines are velocity-flow curves where red denotes areas of high density and blue shows low density. The Milky Way is the black dot on the right-hand side of Laniakea. (Courtesy: Brent Tully et al./Nature)
By Brent Tully at the International Astronomical Union General Assembly in Honolulu, Hawaii
We know that we live on a planet in a solar system in a galaxy in a group of galaxies. But what do we know about our location in the universe beyond that? Some astronomers would answer that we live in the “Local” or “Virgo” supercluster of galaxies. However, the concept has been vague. In the interconnected “cosmic web” it has not been clear where one dense region of galaxies ends and another begins.
Rather than just looking at the distribution of galaxies, it is instructive to consider the motions of galaxies with respect to each other. On the grand scale, galaxies are flying apart from each other with the expansion of the universe. We have to cancel out that motion to see the residual “peculiar” velocities of galaxies that arise from local gravitational attractors.
Fusion power, redefining the kilogram and mimicking the Martian surface are three exciting areas of science and technology that are benefiting from the latest vacuum equipment. In our latest Focus on Vacuum Technology, which you can read free of charge, Christian Day of the Karlsruhe Institute of Technology in Germany explains how new pumping technologies will be crucial to the successful operation of future fusion power plants. “Proving the power of fusion” focuses on the extraordinary vacuum challenges facing the designers of the planned DEMO reactor, which is expected to generate 2 GW of electrical power by the mid-2030s.
Today, the kilogram is defined in terms of a cylinder of a platinum–iridium alloy that was made in the 1880s. Metrology has moved on since then and all of the other SI base units are now defined in terms of fundamental constants. In “The kilogram’s constant struggle”, Stuart Davidson and Ian Robinson of the National Physical Laboratory in Teddington, UK, explain how vacuum technology is playing a crucial role in the development of new ways of defining the kilogram, one of which will ultimately be chosen as the new global standard.
Can the US and Iran seal the deal? (Courtesy: iStockphoto/Kagenmi)
By Matin Durrani
Earlier this month my colleague Hamish Johnston published a blog post about the 70th anniversary of the bombing of Hiroshima, in which he reported on a piece by the science historian Alex Wellerstein about whether that first use of a nuclear weapon for non-testing purposes was justified.
It’s a hugely contentious issue – some say that the Hiroshima and Nagasaki bombings brought to an end a conflict that might otherwise have dragged on much longer, while others claim that a detonation well away from built-up areas would have been a better deterrent. Either way, the Hiroshima anniversary served as a pertinent reminder of the long and controversial role that physicists have played in designing and creating nuclear weapons, from the Manhattan Project onswards.
However, there have been plenty of physicists who have opposed the development of nuclear arms, including the Bulletin of the Atomic Scientists, which was founded in 1945 by Manhattan Project scientists who “could not remain aloof to the consequences of their work”. Another anti-nuclear group is the UK-based Scientists for Global Responsibility, whose executive director Stuart Parkinson is a physicist. Last week it published a report calling for the UK government not to replace its submarine-based Trident nuclear deterrent.
Now, a group of 29 leading US scientists and engineers, including six Nobel laureates, has written a two-page letter to US President Barack Obama backing the deal that the US – along with China, France, Germany, Russia and the UK – has struck with Iran to limit its development of nuclear weapons and permit inspections in return for a lifting of economic sanctions.
Physicists tend to drink lots of coffee so I wasn’t the least bit surprised to see the above video of Philip Moriarty explaining quantum mechanics using a vibrating cup of coffee. Moriarty, who is at the University of Nottingham, uses the coffee to explain the physics underlying his favourite image in physics. You will have to watch the video to find out which image that is, and there is more about the physics discussed in the video on Moriarty’s blog Symptoms of the Universe.
New research looks at the distance from which a candle flame can be seen. (Shutterstock/underverse)
By Andrew Silver
Can the unaided eye see the light from a single candle from 10 miles away? According to some claims on the Internet, the answer is yes – but now two scientists in the US have borrowed techniques from astronomy to show that a pair of binoculars would probably be needed.
The story behind this work began high in the Andes one moonless night when a candle was lit on the Cerro Tololo Inter-American Observatory telescope catwalk. Somebody walked 400–600 m away and said the flame was as bright as the brightest stars in the sky. Nobody wrote down any numbers.
A long-standing tradition of the congress is the production of a daily newspaper for delegates and 2015 is the first year that an electronic version is available to the general public. You can catch up with all the daily news by downloading a copy of Kai‘aleleiaka, which is pronounced “kah EE ah lay-lay-ee AH kah” and means “the Milky Way” in Hawaiian.
Not forgotten: The Hiroshima Peace Memorial is dedicated to the 140,000 people killed in the city. (Courtesty: iStockphoto/Colin13362)
By Hamish Johnston
Today marks the 70th anniversary of the bombing of Hiroshima – the first time that a nuclear weapon was used in war. Many argue that the bombing of Hiroshima, and three days later Nagasaki, was a necessary evil that saved hundreds of thousands of lives by ending the war and avoiding an allied invasion of Japan.
In June 1945 the Nobel laureate James Franck and some colleagues wrote a report that argued that the bomb should first be demonstrated to the world by detonating it over a barren island. Wellerstein surmised that “If the Japanese still refused to surrender, then the further use of the weapon, and its further responsibility, could be considered by an informed world community”. Another idea being circulated at the time was a detonation high over Tokyo Bay that would be visible from the Imperial Palace but would result in far fewer casualties than at Hiroshima, where about 140,000 people were killed.
On the other hand, Wellerstein points out that Robert Oppenheimer and three Nobel laureates wrote a report that concluded “we can propose no technical demonstration likely to bring an end to the war; we see no acceptable alternative to direct military use”. This report was written for a US government committee, which decided to use the weapon against a “dual target” of military and civilian use.
You may remember back in 2013 when researchers at the National Institute of Standards and Technology (NIST) in the US entangled the motion of a tiny mechanical drum with a microwave field for the first time ever. Not content with that feat, NIST physicist Ray Simmonds, who was involved in the work, has now made a dance about it (but no song, yet). Teaming up with choreographer Sam Mitchell, the duo has created a modern dance piece entitled Dunamis Novem (“The chance happening of nine things”). Featuring four dancers, their movements are based on nine quantized energy levels of a harmonic oscillator – like the microscopic drum in the NIST work. For each level, Mitchell created corresponding dance actions, while Simmonds created a random-number generator – to add some “quantum randomness” – for the sequence of levels that the dancers perform at. If the dancers happen to touch each other, their actions become synchronized, which can then only be broken by a beam of light – demonstrating that a measurement collapses the entanglement.
NIST has published a Q&A with Mitchell and Simmonds with links to videos of the dance and the animations of the corresponding energy levels of the harmonic oscillator. A video of the first half of Dunamis Novem is shown above and a video of the entire dance is also available.