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August 2018: Summer Patchwork II: Electric Boogaloo

August 2018

Summer Patchwork, part II. In the show this time, we talk to Kunal Mooley about EM counterparts to gravitational waves, Jake Staberg Morgan rounds up the latest news, and we find out what we can see in the August night sky from Ian Morison and Gaby Perez.

The News

This month in the news: K2 is forced to hibernate, a particle appears in Antarctica and a new scale for close encounters.

You're no doubt familiar with the Kepler spacecraft was launched back in 2009, to find exoplanets using the transit method. Its job was to stare at a single patch of sky over many years to find out if exoplanets were common in our galaxy, and we now know the answer to that question is yes. After its second reaction wheel failed in 2012, Kepler could no longer maintain its stable pointing, and so the craft was re-purposed as the K2 mission. This is presently undertaking a variety of 90-day campaigns across the night sky, using a combination of the remaining two wheels and onboard fuel to point the telescope.

But now, Kepler is running on empty - at the start of July, NASA controllers received a warning that the craft is now running very low on fuel. The remaining reserves are expected to be fully depleted in the next few months. As the craft is in an Earth-trailing orbit, any kind of resupply is impossible, so the priority of the mission team now is to retrieve the data currently on the spacecraft, and then undertake final observations, fuel permitting.

For now, the spacecraft is parked - effectively hibernating, in a so-called "no-fuel-use safe mode". On August 2, it should wake up, orient its antenna towards Earth and beam down the data, which can then be picked up by NASA's Deep Space Network; a network of radio receivers in the US, Spain and Australia. If this is successful, the 19th - and most likely final observing campaign - will commence on August 6th.

In the meantime, scientists are continuing to mine existing data already on the ground. Among other findings, recently 24 new planet discoveries were made using data from K2 Campaign 10, adding to the spacecraft's growing bounty of 2,650 confirmed planets. This treasure trove will likely keep us busy for many years to come!

Last September, an observatory in the Antarctic detected a single particle. This particle was a high-energy neutrino, picked up by the IceCube neutrino observatory; a cubic kilometer's worth of ice embedded with over 5000 optical sensors, constantly looking for the Cherenkov radiation produced by a neutrino interacting with baryonic matter.

As they only interact via the weak nuclear force, such events are extremely rare. IceCube is able to spot one every few minutes, but these events are typically low-energy, usually from cosmic rays striking particles in the Earth's atmosphere and creating a shower of decay products, including neutrinos. We know that the Sun can also generate neutrinos directly, as can violent astronomical events such as supernovae, but this still doesn't account for the whole population. The single neutrino picked up in September 2017 had an energy of 300TeV, 46 times more energetic than the particles circulated by the Large Hadron Collider. Hence, it had to be extragalactic in origin.

Astronomers now think they know where September's neutrino came from, however, thanks to multi-messenger astronomy. By combining IceCube's observation with some rapid X-ray follow-up, nine sources of energetic X-rays were observed. One of these was a blazar - a giant elliptical galaxy with a supermassive, rapidly spinning black hole at its core. This blazar, designated TXS 0506+056, was observed to be flaring - releasing more X-rays and gamma rays than usual. Over the next few days, astronomers looked at the gamma-ray emission of the blazar as observed by the Fermi telescope, and searched through IceCube's archival data spanning nine and a half years. The team found that the blazar had been unusually active, and that an excess of high energy neutrinos had been observed coming from the direction of the blazar. This would suggest, if not outright confirm, that blazars can be a source of high-energy cosmic neutrinos; a success for the burgeoning field of multi-messenger neutrino astronomy.

And finally, if you saw a story about aliens on TV or online, how excited would you be? Here's a more subtle question: if you saw a story about aliens on TV or online, how excited should you be? To answer this question, the Rio Scale is used; a tool used by astronomers searching for extraterrestrial intelligence (ETI) to help communicate to the public 'how excited' they should be about what has been observed. The scale measures the consequences for humans if the signal really is from aliens, as well as the probability that the signal is genuinely extraterrestrial, and not a natural phenomenon or human-made. The scale gives a score between zero and ten, so that the public can quickly see how important a signal really is.

There have been many dubious signals reported as 'aliens' in recent years, and learning the truth about these stories is becoming increasingly difficult. As such, an updated Rio Scale is required. A team of international researchers, led by scientists from the University of St Andrews and the SETI Institute in Mountain View, California, is taking on this task. The new study, led by Dr. Duncan Forgan at the University's Centre for Exoplanet Science, highlights the changing nature of news media, the growth of 24-hour news and the new landscape of social media. Coupled with an increase in efforts to detect ETI by teams around the world, the Rio Scale is needed more than ever, and it must remain relevant when communicating to the public about 'alien signals'.

The lead author on the study, Dr. Forgan, said: "It's absolutely crucial that when we talk about something so hugely significant as the discovery of intelligent life beyond Earth, we do it clearly and carefully. Having Rio 2.0 allows us to rank a signal quickly in a way that the general public can easily understand, and helps us keep their trust in a world filled with fake news."

Interview with Kunal Mooley

Kunal Mooley, recently made a Hintze research fellow at Oxford University, visits JBCA to talk about the electromagnetic counterparts to the gravitational wave event GW170817, spotted in August 2017. He discusses his work on X-ray and radio transients, along with the actual signals that accompanied the gravitational wave, which kickstarted the multimessenger approach to GW science. Furthermore, he discusses his own ambitious plans to take the field of gravitational waves even further.

The Night Sky

Northern Hemisphere

Ian Morison tells us what we can see in the Northern Hemisphere night sky during August 2018.

The Planets

Southern Hemisphere

Gaby Perez from the Carter Observatory in New Zealand speaks about the Southern Hemisphere night sky during August 2018.

Odds and Ends

Ben has also picked up on the redevelopment on the Rio Scale, and gives us some more detail on how it works. We also discuss the broader problems of misinformation, misrepresentation of scientific results by media outlets and the difficulties of making scientific literature less impenetrable and more accessible for the general public.

This episode we talk about the latest in fast radio burst news: CHIME (the Canadian Hydrogen Intensity Mapping Experiment) has detected their first fast radio burst! Fast radio bursts, or FRBs, are bright, short duration bursts of radio light and so far only 36 have ever been detected. We talk about this new CHIME detection, why it's cool, and how it helps us take some steps towards unravelling the mystery of FRBs. You can find out more by checking out the Astronomer's Telegram that announced the news, the CHIME website and @ebpetroff on Twitter for FRB threads and updates.

Have you ever wondered what would happen if the entire Earth was instantaneously replaced by an equal volume of blueberries? At the Jodcast we have been wondering this for years, and are delighted that someone has finally published a paper on this subject! We discuss this seminal work and look at the jam-packed implications of a very real danger that we all face on a daily basis.

Show Credits

News:Jake Staberg Morgan
Interview:Kunal Mooley and Luke Hart
Night sky:Ian Morison and Gaby Perez
Presenters:Laura Driessen, Josh Hayes and Benjamin Shaw
Editors:Emma Alexander, Jake Staberg Morgan and Tom Scragg
Segment Voice:Tess Jaffe
Website:Jake Staberg Morgan and Stuart Lowe
Producer:Jake Staberg Morgan
Cover art:Colourised image of a super-heated blueberry pool. CREDIT: J.S. Morgan

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