Tag Archives: astronomy

The “Super Blood Blue Moon” is just a lunar eclipse

In the last few days I’ve already answered some few emails and questions in social media about the Super Blood Blue Moon happening on the night from 31st January to 1st February 2018. What is this? Is this really important?

Short answer: No, it is not! This is just a lunar eclipse. The rest is hype to sell the story.

Visions of a Total Lunar Eclipse within clouds - 8 October 2014 - Sydney

Visions of a Total Lunar Eclipse within clouds – 8 October 2014 – Sydney. More information and high resolution images in my Flickr. Credit: Ángel R. López-Sánchez.

Long answer: Let me use an email I wrote yesterday replying the questions asked by a journalist about this astronomical event.

1. Can you please define “super moon” “blood moon” and “blue” moon as they occur individually?

—> Supermoon: this is a term that many astronomers (me included) don’t like, as it was introduced by an astrologer (not an astronomer) but it is now very popular. It is just the moment the full moon is happening near the perigee (the Moon in its closest point to Earth). But, that is the important thing, the difference in size of a “supermoon” with respect an average moon is that a supermoon is ~5-6% larger than the average moon. That is almost nothing!!! Many people are confused with the “14% difference” between the supermoon and the micromoon (when the moon is near the apogee, the farthest point to the Earth).

I insist: it is VERY difficult for our naked eye to distinguish a supermoon from an “average” moon.

You can read a lot about this in the post I wrote two years ago and also in the second episode entitled “Blueberry Moon” of the new science podcast “The Skyentists” produced by Kirsten Banks and me.

—> Blood moon: If we astronomers don’t like the term “supermoon”, we really hate the name of “blood moon”. This is just a lunar eclipse!!

—> Blue moon: the now “standard” definition of a blue moon is when a second full moon is happening within the same calendar month. That is, it was full moon on Jan 2nd, the second full moon this month in Jan 31st is a blue moon.

HOWEVER, strictly talking THIS IS NOT TRUE FOR EASTERN AUSTRALIA (NSW, Tasmania, Victoria) and New Zealand, as the moment of the full moon is actually at 00:26am Feb 1st (Sydney/Melbourne time). It is true for Queensland (at 11:26pm Jan 31st), Alice Spring (at 10:56pm Jan 31st) and Perth (9:56pm Jan 31st).

In any case, the ONLY IMPORTANT real astronomical event is that this is a lunar eclipse (the rest is added to create some hype).

You can get plenty of information about the lunar eclipse in this webpage in timeanddate.com and also in this PDF file from NASA Lunar Eclipses.

All the important information for the lunar eclipse happening on the 31st Jan 2018. Credit: F. Espenak / NASA. Here the PDF file.

Australian astronomers have also written about this lunar eclipse. I recommend to have a look to this nice article published by Tanya Hill in The Conversation and also this article by Alan Duffy in Australia’s Science Channel

2. Is this the first time a super blue blood moon has occurred in 150 years?

Probably not, I don’t know, we actually don’t care about this much… It is just a lunar eclipse!!!!

3. How significant is this lunar event?

As I said, it is just a lunar eclipse. That is the point. The rest is added.

4. We are in north-west Victoria. What can people expect to see?

It does not matter where you are in Australia (or in the world, as long as it is night) to see this event. The only differences will be the local weather conditions… if the weather is good, you’ll see a very nice lunar eclipse. It is a perfect opportunity to enjoy the sky!!

5. Are there any tips to getting the best view of the eclipse, or what would be the best times to see it?

The best moment to see the eclipse is when the moon is completely covered by the Earth’s shadow. This happens between 11:52pm and 1:08pm, with the maximum eclipse at 12:30am. You’ll see a red-orange moon in the sky, pretty spectacular.

Addendum 31st Jan: I’ve been using the hashtag #itisjustalunareclipse in social media to say that, at the end… it is just a lunar eclipse!

References:

31 January 2018 — Total Lunar Eclipse in http://www.timeandate.com
PDF file with all info of the lunar eclipse from NASA Lunar Eclipses.
Supermoons, post published in this blog, 11 Nov 2016
A blue blood supermoon is coming, by Alan Duffy in Australia’s Science Channel, 24 Jan 2018
The next Full Moon brings a lunar eclipse, but is it a Super Blood Blue Moon as well? That depends…, Tanya Hill in The Conversation, 29 Jan 2018.
A beginner’s guide to the Moon, Ian Musgrave and Genelle Weule in ABC News, 31 Jan 2018.
The “Trifecta” Lunar Eclipse on January 31st, great article by Kelly Beatty in Sky & Telescope, 29 Jan 2018.

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The first detection of an electromagnetic counterpart to a gravitational wave event

Full AAO Media Release, published at 01:00am Sydney time, 17 October 2017, that I coordinated.

For the first time, astronomers have observed the afterglow of an event that was also detected in gravitational waves. The object, dubbed AT2017gfo, was a pair of in-spiralling neutron stars in a galaxy 130 million light years away. The death spiral was detected in gravitational waves, and the resulting explosion was followed by over 50 observatories world wide, including the AAO and other observatories here in Australia.

On August 17, the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO), based in the United States, detected a new gravitational wave event, called GW170817.

GW170817 is the fifth source of gravitational waves ever recorded. The first one was discovered in September 2015, for which three founding members of the LIGO collaboration were awarded the 2017 Nobel Prize in Physics.

The GW170817 data are consistent with the merging of two neutron stars and are unlike the four previous events, which were merging black holes.

Artist’s illustration of two merging neutron stars. The narrow beams represent the gamma-ray burst while the rippling space-time grid indicates the gravitational waves that characterize the merger. Swirling clouds of material ejected from the merging stars are a possible source of the light that was seen at lower energies. Credit: National Science Foundation/LIGO/Sonoma State University/A. Simonnet.

The Advanced-Virgo interferometer, based in Italy, was online at the time of the discovery and contributed to the localization of the new gravitational wave burst.

Based on information from LIGO and VIRGO, numerous telescopes immediately sprang into action to determine if an electromagnetic counterpart to the gravitational waves could be detected.

Meanwhile, NASA’s Fermi satellite independently reported a short burst of gamma-rays within 2 seconds of the merger event associated with GW170817, consistent with the area of sky from which LIGO and VIRGO detected their gravitational waves.

This gamma-ray detection at the same time and place triggered even greater interest from the astronomical community and resulted in more intense follow up observations in optical, infrared and radio wavelengths.

A team of scientists within the Dark Energy Survey (DES) collaboration, which includes researchers from the Australian Astronomical Observatory and other Australian institutions, working with astronomers at the Harvard-Smithsonian Center for Astrophysics (CfA) in the U.S., were among the first astronomers to observe the electromagnetic counterpart of GW170817 in optical wavelengths.

Using the 570-megapixel Dark Energy Camera (DECam) mounted at the 4m Blanco Telescope at Cerro Tololo Inter-American Observatory in Chile, DES identified the kilonova AT2017gfo in the nearby galaxy NGC 4993, located only 130 million light years from us, as the optical counterpart of GW170817.

Composite of detection images, including the discovery z image taken on August 18th and the g and r images taken 1 day later. Right: The same area two weeks later. Credit: Soares-Santos et al. and DES Collaboration.

“Because of its large field of view, the Dark Energy Camera was able to search almost the entire region where LIGO/VIRGO expected the gravitational wave source to be, and its exquisite sensitivity allowed us to make detailed measurements of the kilonova – the extremely energetic outburst created by the merging neutron stars,” AAO Instrument Scientist and DES Collaboration member Dr Kyler Kuehn stated.

A kilonova is similar to a supernova in some aspects, but it is different in others. It occurs when two neutron stars crash into each other. These events are thought to be the mechanism by which many of the elements heavier than iron, such as gold, are formed.

“But as impressive as it is, the Dark Energy Camera is only one of many instruments with a front row seat to this celestial spectacle. A lot of effort has gone into preparing dozens of telescopes around the world to search for electromagnetic counterparts to gravitational waves”, Dr Kuehn added.

Simultaneously to the DES study, a large group of Australian astronomers obtained follow up observations of the kilonova AT2017gfo at optical, infrared and radio wavelengths, using 14 Australian telescopes as part of the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) and other Australian programs.

Their data are consistent with the expected outburst and subsequent merger of two neutron stars, in agreement with the results derived for GW170817 by the LIGO/Virgo collaboration.

“Before this event, it was like we were sitting in an IMAX theatre with blindfolds on. The gravitational wave detectors let us ‘hear’ the movies of black hole collisions, but we couldn’t see anything. This event lifted the blindfolds and, wow, what an amazing show!!”, A/Professor Jeff Cooke, astronomer at Swinburne University who led many of the observations said.

The Australia team also conducted observations at the 3.9m Anglo-Australian Telescope (AAT), that is managed by the Australian Astronomical Observatory (AAO). Additional archive data from the 6dF survey obtained at the AAO’s 1.2m UK Schmidt Telescope were also used.

“The observations undertaken at the AAT place important constraints on the nature of the environment in which the kilonova occurred”, AAO astronomer Dr Chris Lidman said.

The follow up observations were not scheduled, but the excitement that this event generated in the astronomical community was so large that regular programs were placed on hold.

“Many astronomers dropped any other planned observation and used all the available resources to study this rare event”, said PhD candidate Igor Andreoni (Swinburne University and Australian Astronomical Observatory), first author of the scientific paper that will be published in the science journal “Publications of the Astronomical Society of Australia” (PASA).

The study also reveals that the host galaxy has not experienced significant star-formation during the last billion years. However, there is some evidence that indicates that NGC 4993 experienced a collision with a smaller galaxy not long time ago.

The position of the kilonova AT2017gfo, found in the external parts of NGC 4993, may suggest that the binary neutron star could have been part of the smaller galaxy.

Australian astronomers were thrilled to contribute to both the detection and the ongoing observations of the kilonova AT2017gfo, the electromagnetic counterpart to the gravitational wave event GW170817.

“We have been waiting and preparing for an event like this, but didn’t think it would happen so soon and in a galaxy that is so near to us. Once we were alerted of the gravitational wave detection, we immediately contacted a dozen telescopes and joined the worldwide effort to study this historic event. It didn’t let us down!”, A/Professor Jeff Cooke said.

“It was crucial to have telescopes placed in every continent, including Australia, to keep this rare event continuously monitored”, PhD candidate Igor Andreoni said.

“To me, this gravitational + electromagnetic wave combined detection is even more important than the initial detection that resulted in the Nobel Prize. This has changed the way the entire astronomical community operates”, AAO Instrument Scientist Dr Kyler Kuehn stated.

The first identification of the electromagnetic counterpart to a gravitational wave event is a milestone in the history of modern Astronomy, and opens a new era of multi-messenger astronomy.

More information:

AAO Media Release

AAO Media Release in Spanish / Nota de prensa del AAO en español

LIGO Media Release

DES Media Release

OzGrav Media Release

ESO Media Release

NASA Media Release

Article in The Conversation: “After the alert: radio ‘eyes’ hunt the source of the gravitational waves”, by Tara Murphy and David Kaplan

Article in The Conversation: “At last, we’ve found gravitational waves from a collapsing pair of neutron stars”, by David Blair

Multimedia, videos and animations:

Although there are many videos around there talking about this huge announcement, I particularly like this one by Derek Muller (Veritasium):

Historic ESO-Australia agreement

This is BIG. Australian astronomers have tried for almost 2 decades to be part of the European Southern Observatory (ESO). Yesterday, 11th July 2017, at a ceremony happening during the Annual Meeting of the Astronomical Society of Australia (ASA) in Canberra, Australia, ESO’s Director General, Tim de Zeeuw, and the Australian Minister for Industry, Innovation and Science, Arthur Sinodinos, signed a 10 years Strategic Partnership between Australia and ESO.

Image composition showing all the ESO observatories and the Headquarters. Credit: ESO/M. Kornmesser.

Following the ESO-Australia Strategic Agreement, Australian astronomers (including me!) will have access to telescope time at La Silla and Paranal Observatories in Chile. The ESO-Australia Strategic Agreement also provides crucial opportunities for Australian influence and technical and scientific input, stimulating international research and industry collaborations.

This is particularly important for the Australian Astronomical Observatory (AAO), as we are developing key instrumentation for ESO (as the ESOP positioner for the VISTA telescope), and that was a key part of the deal, with new opportunities to develop further telescope instrumentation in the nearby future. That also means an important re-arrangement within the AAO, which details are still unknown, but in which we’ll give our best.

At a ceremony in Canberra, Australia, on 11 July 2017, an arrangement was signed to begin a ten-year strategic partnership between ESO and Australia. The partnership will further strengthen ESO’s programme, both scientifically and technically, and will give Australian astronomers and industry access to the La Silla Paranal Observatory. It may also be the first step towards Australia becoming an ESO Member State.
This picture shows all the signatories of the arrangement. From left to right: Virginia Kilborn, President of the Astronomical Society of Australia, Warrick Couch, Director of the Australian Astronomical Observatory, Sue Weston, Deputy Secretary, Department of Industry, Innovation and Science, Senator the Hon Arthur Sinodinos, Minister for Industry, Innovation and Science, Tim de Zeeuw, ESO Director General, Brian Schmidt, Vice Chancellor of the Australian National University, Laura Comendador, Head of the ESO Cabinet and Patrick Geeraert, ESO Director of Administration. Credit: Australian Government.

The Australian Government will invest $129 million over 10 years in the partnership, including the $26.1 million already announced for 2017-2018 Australian Budget. This may also be the first step towards Australia becoming an ESO Member State.

Exciting times await!

More details:

“Stargazing in the Calyx”, new Science Communication Event series at Sydney’s Botanic Gardens

Article originally written by Ángel R. López-Sánchez for the “AAO Observer” 132, August 2017.

In June 2017 the Australian Astronomical Observatory (AAO) started a new Science Communication collaboration with historic Sydney’s Royal Botanic Gardens. The events “Stargazing in the Calyx” combine a short talk given by an astronomer followed by a stargazing session with amateur telescopes.

People are enjoying the view of the sky through amateur telescopes during the “Stargazing in the Calyx” science communication event at Sydney’s Botanic Gardens on Tuesday 4th July 2017. Credit: Christina McGhee (Sydney’s Botanic Gardens).

The first of these events was held on Monday 19th June 2017. It was so successful that the following “Stargazing in the Calyx” session, scheduled on Tuesday 4th July, was sold out in just 8 minutes after the tickets were available.

The organization of these events have received a hugely positive feedback, both about the venue (the brand-new “The Calyx” building at Sydney’s Botanic Gardens) and the atmosphere (people enjoyed dinner with drinks under the stars) and the entertaining and knowledgeable talks about the Southern Sky (given by AAO and Macquarie University astronomer Ángel López-Sánchez).

AAO/MQU astronomer Ángel López-Sánchez giving his talk “Introduction to the Southern Sky” as part of the “Stargazing in the Calyx” event at Sydney’s Botanic Gardens on Monday 19th June 2017. Credit: Christina McGhee (Sydney’s Botanic Gardens).

Besides some clouds and Sydney’s light pollution, participants really enjoyed the views of planets Jupiter and Saturn and the Moon through the telescopes, as well as observing globular cluster Omega Centauri and the famous “Jewel Box” star cluster in the Southern Cross, as well as learn to recognize the constellations of the winter nights at the southern hemisphere. Some of the telescopes were kindly provided by CSIRO, Sydney University, Macquarie University and some amateur astronomers who were also invited to these events.

The next “Stargazing a the Calyx” event is scheduled on Tuesday 3rd of October. We expect they will be repeated each 1 or 2 months.

“The Story of Light: Surveying the Cosmos”, in Vivid Sydney Ideas 2017

Article originally written by Ángel R. López-Sánchez for the “AAO Observer” 132, August 2017.

Following the success of our sold-out Event “The Story of Light – The Astronomer’s Perspective” for ViVID Sydney Ideas 2015, and “The Story of Light – Deciphering the data encoded on the cosmic light” (see photos and the video of this event), the Australian Astronomical Observatory (AAO) continued its collaboration with ViVID Sydney 2017 organizing “The Story of Light – Surveying the Cosmos”.

This successful science communication event was held at the Powerhouse Museum (Sydney) on Sunday 4th June 2017. Having an audience of 300 people, it was sold out more than two weeks before the event.

“The Story of Light – Surveying the Cosmos” was connected to the 2017 Southern Cross Astrophysics Conference: Surveying the Cosmos, the Science from massively multiplexed surveys, that was held in Luna Park, Sydney, between 5th and 9th June 2017.

Poster for the AAO’s “The Story of Light – Surveying the Cosmos” Science Communication event for Vivid Sydney Ideas 2017. Credit: Angel R. Lopez-Sanchez.

In this event, five professional astrophysicists discussed how astronomers map the Cosmos using the big data collected with optical and radio telescopes by large astronomical surveys.

How do astronomers explore the Universe? Astrophysicists use extremely sensitive telescopes and instruments to collect the light emitted by stars, gas and galaxies. The analysis of this data provides the information needed to unlock the mysteries of the Cosmos.

However, this is not an easy task. Over the last two decades large international collaborations have been formed with the aim to map the skies, catalogue celestial objects, extract their properties and perform statistical analyses. These large astronomical surveys are now providing major advances in our understanding of the Cosmos at all scales, from searching for planets around other stars to detecting gravitational waves.

Australia is at the forefront of these collaborations thanks to the unique instruments at the Anglo-Australian Telescope (AAT) and the development of radio-interferometers as the Australian SKA Pathfinder (ASKAP).

Panel members and MC of AAO’s “The Story of Light – Surveying the Cosmos” Science Communication event for Vivid Sydney Ideas 2017. From left to right: Katie Mack, Alan Duffy, Simon O’Toole, Tara Murphy and Ángel López-Sánchez. Credit: Duncan Wright (AAO/UNSW).

The panel members were Dr. Simon O’Toole (Australian Astronomical Observatory), who talked about surveying stars and exoplanets, Dr. Ángel R. López-Sánchez (Australian Astronomical Observatory / Macquarie University), who discussed how we surveying the galaxies, A/Prof. Tara Murphy (University of Sydney / CAASTRO), who invited us to surveying the invisible Universe, and Dr. Katie Mack (University of Melbourne), who talked about surveying the deep Universe. The event was hosted by famous astrophysicist and science communicator A/Prof. Alan R. Duffy (Swinburne University).

After short (15 minutes) talks, the panel answered questions about the Universe and challenging Physics questions as the nature of the dark matter and the dark energy. They also received some more philosophical questions that engaged the audience.

More information:

Successful BBC and ABC Stargazing Live TV events at Siding Spring Observatory

Article originally written by Ángel R. López-Sánchez for the “AAO Observer” 132, August 2017. Credits of all the photos: Ángel R. López-Sánchez.

Colorful lights in dome of our Anglo-Australian Telescope in preparation for the Stargazing Live TV shows.

During two weeks in late March and early April 2017, famous physicist and TV presenter Professor Brian Cox co-hosted two “Stargazing TV” shows emitted live from Siding Spring Observatory in the BBC and in the ABC. The stage of these major TV events was our Anglo-Australian Telescope, (AAT) at Siding Spring Observatory, on the edge of the Warrumbungle National Park near Coonabarabran, NSW.

BBC Stargazing Live shows at Siding Spring Observatory were emitted on the early morning of Wednesday 29th, Thursday 30th and Friday 31st March 2017 (evenings of the previous days in the UK). BBC Stargazing Live TV shows were hosted by Professor Brian Cox and TV presenter and comedian Dara Ó Briain, with the participation of biologist and BBC presenter Liz Bonnin and Broome-based amateur astronomer Greg Quicke (who was very popular in social media, receiving the nickname of #SpaceGandalf).

During BBC Stargazing Live astrophysicist and science communicator Lisa Harvey-Smith (CSIRO) was also interviewed. Astronomer and journalist Chris Lintott (Oxford University) was in charge of reporting the news of the citizen science project “The Search for Planet 9“, led by astronomers at the Australian National University and launched in the first episode of BBC Stargazing Live. This citizen science project uses images taken with the Skymapper telescope at Siding Spring Observatory to search for a new planet in our Solar System.

#StargazingABC live episodes were emitted the following week (Tuesday 4th, Wednesday 5th and Thursday 6th April 2017). Hosts Professor Brian Cox and TV presenter Julia Zemiro were joined by astronomers to inspire Australia to explore our Universe and tackle astronomy’s most intriguing questions. Astronomer Lisa Harvey-Smith (CSIRO) also participated as TV presenter for the #StargazingABC shows.

AAO’s Fred Watson, Steve Lee and David Malin were interviewed several times during the ABC and BBC Stargazing Live shows.

SAMI observers at the Anglo-Australian Telescope shared the dome with ABC crew while preparing instrument and telescope for observations on the afternoon of Sunday 2nd April.

For #StargazingABC first episode, the Milky Way, AAO astronomers Ángel López-Sánchez and Steve Lee prepared a new astronomical color image using data taken with the CACTI auxiliary camera of the AAT, which was broadcasted in the episode. This image shows Diffuse gas and dust in the heart of the Carina Nebula. The bright star is Eta Carinae, a massive double star at the end of its live that will soon explode as a supernova. The “Keyhole” is the dark cloud in the centre of the image.

Both Stargazing Live ABC events were very successful. #StargazingABC live episodes reached 2.7 million viewers across metro and regional Australia. They also had a huge impact in social media. ABC 1st TV episode reached over 240K people and had more than 8K reactions in Facebook, comments and shares, similar numbers to those obtained with ABC TV’s New Year’s Eve Family Fireworks stream. Regarding Twitter, the #StargazingABC hashtag reached 18.4 million users and produced 16.8K tweets from 6.3K unique contributors. 12.8K of these tweets were produced during the broadcasts, making #StargazingABC trend no.1 in Australia.

Credits of all the photos: Ángel R. López-Sánchez.

More information: AAO news: ABC Stargazing Live at the AAT.

Image

Eta Carinae and the Keyhole Nebula

Eta Carinae and the Keyhole Nebula

Diffuse gas and dust in the heart of the Carina Nebula. The bright star is Eta Carinae, a massive double star at the end of its live that will soon explode as a supernova. The “Keyhole” is the dark cloud in the centre of the image.

Image obtained as part of the “ABC Stargazing Live” events at Siding Spring Observatory (NSW, Australia), 4 – 6 April 2017.

Data taken on 3rd April 2017 using the CACTI camera in 2dF at the 3.9m Anglo-Australian Telescope. Color image using B (12 x 60s, blue) + [O III] (12 x 60 s, green) + Hα (12 x 60 s, red) filters.

More sizes and high-resolution image in my Flickr.

Credit: Ángel R. López-Sánchez (Australian Astronomical Observatory and Macquarie University), Steve Lee, Robert Patterson & Robert Dean (AAO), Night assistant at the AAT: Wiston Campbell (AAO).