Posts by: Hamish Johnston

What gravitational waves did (and didn’t) tell us about GW17081

100 s countdown: Jocelyn Read (centre) and undergraduate students Isabella Molina (left) and Erick Leon (Courtesy: CQG+)

Rotating into view: Jocelyn Read (centre) and undergraduate students Isabella Molina (left) and Erick Leon (Courtesy: CQG+)

 

By Hamish Johnston

The GW170817 neutron-star merger was by no means an instantaneous event. Physicists working on the LIGO-Virgo gravitational-wave detectors were able to watch the two stars spiral towards each other for about 100 s before they merged. Valuable information about the neutron stars has been gleaned from the observation, but the detectors were unable to see the merger itself and its aftermath.

In “The gravitational-wave story of a neutron-star merger”, Jocelyn Read of California State University Fullerton takes up the story at 17 min before the merger. Then, the neutron stars would have been be separated by about 700 km and have an orbital frequency of about 10 Hz.

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Neutron star merger as it happened

All around the world: observatories that looked-out for GW170817 (Courtesy: LIGO-Virgo)

All around the world: observatories that saw GW170817 (Courtesy: LIGO-Virgo)

By Hamish Johnston

At 12:41:20 UTC on 17 August, the Fermi Gamma-ray Space Telescope sent a notice to the astronomy community saying that it had detected a gamma-ray burst. Normally such an event wouldn’t raise much fuss – but this time things would be very different.

Back on Earth, scientists working on the LIGO-Virgo gravitational wave detectors were busy analysing a signal that had arrived about 2 s before the gamma-ray burst and looked very much like the merger of two neutron stars. Such a cataclysmic event is expected to give off copious amounts of electromagnetic radiation including an initial burst of gamma rays.

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How does LIGO detect gravitational waves?

 

By Hamish Johnston

This year’s physics Nobel prize has gone to three physicists who pioneered the LIGO observatory, which in 2015 made the first-ever detection of gravitational waves.

The LIGO detectors are famously capable of detecting changes in length smaller than one thousandth the diameter of a proton.

So how is this done?

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Nobel prize heralds new era of multimessenger astronomy

Brave new worlds: what LIGO-Virgo could see (click on image to expand). (Courtesy: I Bartos and M Kowalski)

Brave new worlds: what LIGO–Virgo could see. Click on image to expand. (Courtesy: I Bartos and M Kowalski)

By Hamish Johnston

I think it’s safe to say that most Nobel-watchers were predicting a LIGO-related physics prize this year, and for very good reasons.

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Great wrong theories, new spin on golf, physics photo competition

 

The Standard Model: wrong, but wonderfully wrong (Courtesy: Eric Drexler)

The Standard Model: wrong, but wonderfully wrong (Courtesy: Eric Drexler)

By Hamish Johnston

What is the greatest wrong theory in physics? Physicist Chad Orzel asks that question in his latest blog for Forbes and by wrong he does not mean incorrect, but rather incomplete. He makes the argument for the Standard Model, which he says has been wrong for a very long time – but continues to be phenomenally successful.

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Quantum quartet is on the cards

Quantum pair: Wolfgang Pauli and Werner Heisenberg (Courtesy: Sabine Hossenfelder)

Quantum pair: Wolfgang Pauli and Werner Heisenberg (Courtesy: Sabine Hossenfelder)

By Hamish Johnston

Theoretical physicist and blogger Sabine Hossenfelder has created a lovely set of cards featuring pioneering quantum physicists. You can see my two favourites above.

Resembling football or baseball cards, they each feature a portrait plus a fact or two about the physicist – including a salacious aspect of Erwin Schrödinger’s personal life. You will have go to Hossenfelder’s blog to learn more about that – and see the rest of the cards, including a feline “Bra-ket” as the joker of the deck.

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Reminiscing about Fermilab, CAPTCHA tests your physics, science of guitar strings

By Hamish Johnston

What do huge snowstorms, pioneering childcare and bison have in common? The answer is that they all feature in video recollections of Fermilab, the particle physics facility that is celebrating its 50th anniversary this year. A playlist of the videos is available and you can watch Cindy Joe’s musings over Snowpocalypse 2011 above.

According to physics blogger ZapperZ, the online retailer Amazon is developing a new CAPTCHA technology that relies on human’s innate understanding of the laws of physics. The idea, apparently, is that a user would be presented with before and after scenarios and asked which seem plausible. This could be a ball rolling down a ramp, or a projectile flying through the air. It seems that web robots can’t solve simple mechanics problems – at least for now.

Ending on a bright note, music technologist and erstwhile physicist Jonathan Kemp of the University of St Andrew’s in Scotland claims to have invented a revolutionary type of guitar string. He riffs on his new creation in the video above.

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Prize-winning astronomy image, the ultimate cost of Cassini, amazing facts about lasers

 

Prize winning: Rho Ophiuchi Cloud Complex captured by Artem Mironov (Courtesy: Artem Mironov)

Prize winning: the Rho Ophiuchi Cloud Complex captured by Artem Mironov (Courtesy: Artem Mironov)

By Hamish Johnston and Michael Banks

Hats off to the Russian photographer Artem Mironov, who has beaten thousands of amateur and professional photographers from around the world to win the 2017 Insight Astronomy Photographer of the Year. The award is in its ninth year and is run by the Royal Observatory Greenwich together with Insight Investment and BBC Sky at Night magazine. Mironox’s image, which was taken over three nights from a farm in Namibia, is of the swirling dust and gas clouds in the Rho Ophiuchi Cloud Complex. The object is situated approximately 400 light years away from Earth and is home to a cluster of more than 300 protostars. As well as winning the £10,000 top prize, Mironov’s image will be on display along with other selected pictures at an exhibition at the Royal Observatory that will run until 28 June 2018. The competition received over 3800 entries from over 90 countries. (more…)

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Why is quantum physics so hard to write about?

Live at Leeds: George Musser riffs on writing about quantum mechanics (Courtesy: H Johnston)

Live at Leeds: George Musser riffs on writing about quantum mechanics (Courtesy: H Johnston)

By Hamish Johnston

Why is quantum physics so hard to write about?

That was the theme of George Musser’s keynote talk at a seminar for science communicators held this week at the University of Leeds. Musser – who has written extensively on topics such as quantum entanglement and string theory – gave several reasons and here are a few that stuck in my mind.
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A punt on Planck, physicist puts Frankenstein to music, would Brian Cox cope on Mars?

Fancy a flutter? The NIST napkin (Courtesy: NIST)

Fancy a flutter? The NIST napkin. (Courtesy: NIST)

By Hamish Johnston

A paper napkin with a load of numbers scrawled on top has been an unusual source of excitement for physicists at the US National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland. One evening in December 2013, a group of them had gathered at a local watering hole to celebrate the success of NIST’s latest watt balance – NIST-3 – that had just determined Planck’s constant to a new accuracy. While enjoying “happy hour”, NIST researcher Dave Newell pulled out a napkin and the 10 researchers began to write down their predictions for the final value of Planck’s constant that NIST would submit to the International Bureau of Weights and Measures in Paris to help redefine the kilogram. The researchers then sealed the napkin in a plastic bottle and buried it inside a cavity within the foundation of NIST-3’s successor NIST-4, which was then being constructed.

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