Spooky. In the show this time, we talk to Dr. Caroline D'Angelo about accretion around extreme objects, Ian rounds up the latest news, and we find out what we can see in the November night sky from Ian Morison and Haritina Mogosanu.
In the news this month: gravitational wave rumours abound, Great Red Spot shrinks and astronomers open a discussion about sexual harrasment.
Following its re-opening, as discussed on last month's Jodcast, the LIGO gravitational wave observatory has already this month generated an exciting, plausible rumour of a detection of a gravitational wave event. Arizona State University cosmologist and science communicator Lawrence Krauss was the first to publicly comment on a rumour which had already been circulating amongst scientists, tweeting "Amazing if true. Will post details if it survives." Such a detection would indeed be amazing, representing the first time a gravitaional wave had been directly detected, confirming a major prediction of Einstein's General Relativity and providing immediate return on LIGO's two hundred million dollar recent overhaul and upgrade.That the blind injection procedure existed was known to the whole collaboration however, so there was not too much disappointment when it was revealed at a conference to have all been a drill. Such blind data challenges are invaluable in testing equipment, data analysis methods and also the mentality of scientists -- proving that the methods work and that the people involved are capable of avoiding factors such as 'confirmation bias' in which analysts can, even unconciously, favour data which meets their preconceived expectations. By showing that the analysis pipelines were able to perform correclty on the simulated data any future real detections by LIGO will be regarded as that much believable. It is also true that the 2010 test was not a complete success. The detection appeared to be coming from the direction of Canis Major and quickly became known as the 'Big Dog' event. But the simulated signal which had been injected corresponded to a gravitational wave event in a completely different direction on the sky. The error was quickly traced to a pernicious source known to all physicists: a sign error in some of the code used by the injection team had in fact caused the signal to have been be injected upside down!
Also in the news this month, analysis of images taken by the Hubble Space Telescope have shown that Jupiter's Great Red Spot has shrunk to its smallest size yet. The Great Red Spot is a distinctive storm which has raged in Jupiter's Southern hemisphere for at least 350 years. It is tens of thousands of kilometres across -- big enough to swallow more than one whole Earth -- and hosts wind speeds of over 250 miles an hour. The spot has however been shrinking for several years, with at least a 15 percent decline in its diameter observed between 1996 and 2006. The latest observations were taken by Hubble in January of this year as part of a set of images mapping the entire planet twice in a ten hour period. The atmosphere of Jupiter is a complex and beautiful place, composed mostly of Hydrogen and helium along with methane, ammonia, hydrogen sulfide, water and more. The atmosphere evolves significantly on even the short timescales covered by the new observations, but the Red Spot itself rotates around once every six Earth days, or 14 Jovian days. Predicting what will happen to the storm next is hard; listeners may be familiar with the fact that weather forecasting has significant difficulties even in situ here on Earth. It *is* understood that Jupiter's climate is changing, with a variation of up to ten Kelvin expected and apparently driving new storms such as 'Oval BA' (or 'Red Spot Junior') which formed South of the Great Red Spot in 2000 from several smaller storms known about since the 1930s.
And finally, astronomers this month have been reacting to the news of a sexual harrasment case involving prominent exoplanet researcher Geoff Marcy. The news was broken when the BuzzFeed News website published that Marcy had been the subject of an investigation by the University of California at Berkeley, his employer, into harrasment offences against multiple female students between 2001 and 2010. Reaction from the astronomy community at large has been signficant, expressing support for the scientists who were victims and concerns at how UC Berkeley dealt with Marcy's damaging actions. Marcy is an extemely prominent astronomer, notable as being one of the first to discover exoplanets -- planets orbiting stars other than our own Sun -- and was a tenured Professor at UC Berkeley, member of the team working on NASA's Kepler satellite and had recently lead the Breakthrough Listen project awarded one hundred million dollars by a private benefactor to look for signs of life on exoplanets. How astronomy deals with harrasment by prominent individuals is a significant topic; it is important to remember the field is in no way immune to sexual harrasment incidents.In the case of Geoff Marcy, it took nearly ten years befor a joint complaint was made by four people who had either been victims of or witnessed his inappropriate behaviour. At least one of the complainants pointed to Marcy's actions as a strong component in their reasons for leaving astronomy. Much contention has focused on the response from the authorities at UC Berkeley, who only weakly disciplined Marcy -- providing "expectations on his future interactions with students", which he was to follow or possibly face sanctions in the future. Furthermore, details of the investigation would not have been made public were it not for the BuzzFeed News article. This pattern of long-term transgressions only weakly punished when finally reported supports the widely held perception within academica that institutions can often be reluctant to discipline or remove 'brilliant' scientists -- who supply considerable prestige and research income. This can lead to senior academics being seen as becoming almost untouchable, contrasting with the dispensible nature of more junior students and post-docs who face fierce competition for short term contracts in a small community and undergraduates concerned for their academic success. Incidents of sexual harrasment and sexism are also frequently pointed to as an underlying cause for astronomy's gender imbalance, which becomes increasingly severe at more senior levels. 2013 data from the AAS Committee on the Status of Women in Astronomy shows a decline in the representation of women as careers progress from ~25 percent at grad student to ~10 percent at full professor, replicated in similar data sets from the UK. Similar gender disparities appear in amateur astronomy, with only 9 percent of Sky & Telescope magazine's subscibers identifying as female, and some 14 percent of Jodcast listeners when last surveyed in 2010. Following the reporting of the case, the wider astronomical community has provided a much stronger and more inclusive response than the formal authorities involved. Statements from the American Astronomical Society; Royal Astronomical Society; some 3000 astronomy professionals; and UC Berkeley staff, post-docs and graduate students all condemmed Marcy's actions and Berkeley's weak response and supported the victims. In particular, the staff at Marcy's insitution commented that they believe he "cannot perform the functions of a faculty member." in terms of having interactions with students, in light of his actions. This has apparently had an effect, with Marcy announcing his resignation from his position at the University of California and in the Breakthrough Listen Collaboration. This incident clearly needs to be part of an ongoing process in which astronomy, and academia in general, becomes more open and better at dealing with harrasment complaints. Whilst all major institutions will have anti-harrasment poilicies complying with local laws, these policies are seldom enforced and seen to be enforced, creating an unwelcoming atmosphere for anyone who could be made to feel vulnerable. Hopefully the news about Geoff Marcy will continue the progress which has already been made in making the astronomy community as open and inclusive as possible.
Interview with Dr. Caroline D'Angelo
Dr Caroline D'Angelo is a research associate at the University of Leiden, Netherlands. She is currently studying accretion around extreme objects such as neutron stars, and discusses the role accretion plays as 'the most efficient engine in the Universe' in the evolution of neutron stars, and describes how some may transition on timescales of around one month between incredible brightness and extreme dimness. She also discusses a very special pulsar which displays properties reminiscent of a theoretical model which she developed over the course of her PhD!
The Night Sky
Ian Morison tells us what we can see in the northern hemisphere night sky during November 2015.
Highlights of the month
November early mornings - meteors
In the hours before dawn, November gives us a chance to observe meteors from two showers - the Northern Taurids shower and the better known Leonids. The Northern Taurids shower has a broad peak of around 10 days but normally gives relatively few meteors per hour. The peak is around the 10th of November and, pleasingly, the Moon is new on the 11th. The meteors arise from comet 2P/Encke, which has a tail especially rich in large particles, so it is possible that a number of fireballs might be observed!
The Leonids are also expected to produce bright events, peaking on the night of the 17th/18th of the month, with up to 15 meteors an hour visible to those near the zenith. The Moon sets at 21:30 on the 17th so will not be a problem when observing the first predicted peak at 21:00 UT on the 17th and the second at 04:00 on the 18th. As one might expect, the shower's radiant lies within the sickle of Leo and meteors could be spotted from the 15th to the 20th of the month. The Leonids enter the atmosphere at ~71 km/sec and this makes them somewhat challenging to photograph but it's worth trying as one might just capture a bright fireball. The Leonids are famous because every 33 years a meteor storm might be observed when the parent comet, 55P/Temple-Tuttle, passes close to the Sun. In 1999, 3,000 meteors were observed per hour but we are now halfway between these impressive events hence with a far lower expected rate.
November 3rd - before sunrise: Venus and Mars under a degree apart.
Before dawn on the 3rd, brilliant Venus shining at magnitude -4.5 will be very close to Mars at magnitude +1.7. Jupiter will lie ~7 degrees to their upper right.
November 7th - before sunrise: A thin crescent Moon joins the morning planets.
An excellent imaging opportunity arises before dawn on the 7th as a thin crescent Moon lies close to Venus and Mars with Jupiter some 9 degrees to their upper right.
Find The Andromeda Galaxy (M31) around the second week of November - and for an extra challenge, perhaps M33 in Triangulum
In the evening, the galaxy M31 in Andromeda is visible in the south. The chart on the Jodrell Bank night sky page shows two ways of finding it:
- Find the square of Pegasus Start at the top left star of the square - Alpha Andromedae - and move two stars to the left and up a bit. Then turn 90 degrees to the right, move up to one reasonably bright star and continue a similar distance in the same direction. You should easily spot M31 with binoculars and, if there is a dark sky, you can even see it with your unaided eye. The photons that are falling on your retina left Andromeda well over two million years ago!
- You can also find M31 by following the "arrow" made by the three rightmost bright stars of Cassiopeia down to the lower right as shown on the chart.
November 25th to 30th - 1 hour before sunrise: Jupiter rises higher in the sky.
In the last week of November, Jupiter, rising 40 minutes after midnight, will have reached an elevation of 20 degrees or more for 2 hours of astronomically dark sky. Then will be the time to start seriously observing and imaging it. This is a great opportunity to take a look at its Great Red Spot - is it still shrinking?
November 25th - evening: The full Moon close to the Hyades Cluster.
This evening, the full Moon will be seen just to the right of the Hyades Cluster in Taurus. Lying halfway towards the cluster is the red-giant star Aldebaran.
Jupiter is now a wonderful morning object, rising soon after midnight by the last week of November. On the morning of the 24th of October I saw it lying close to brilliant Venus as a prelude to this month's morning parade of the planets Mars, Venus and Jupiter. Jupiter starts the month shining at magnitude -1.8 with an angular diameter of 33 arc seconds. During the month, these increase to -2.0 and 35.5 respectively. It lies in Leo, 8 degrees over to the right of Denebola and is gradually moving down towards Virgo before it starts its retrograde motion in January. With a small telescope, early risers should be able to see the equatorial bands in the atmosphere and the four Gallilean moons as they weave their way around it.
Saturn passes behind the Sun on the 29th of November. It might just be seen using binoculars at the very beginning of the month, just a few degrees above the southwestern horizon 45 minutes after sunset but, really, we will have to wait for a while yet to see it in the pre-dawn sky.
Mercury reaches superior conjunction (that is, on the far side of the Sun) on November 17th and will not be visible for much of the month. It might just be picked up using binoculars low in the east about 20 minutes before sunrise in the first few days of the month.
Mars rises about 3:30 am as the month begins, shining at magnitude +1.7. This increases to magnitude +1.5 as the month progresses with its angular diameter increasing from 4.2 to 4.7 arc seconds. This is still too small for any details to be seen on its salmon-pink surface. As the highlights have detailed, at November's start, it will lie close to both Jupiter and Venus, making a wonderful grouping in the sky. However, by month's end, Mars will be about 20 degrees to the lower left of Jupiter and 14 degrees to the upper right of Venus. It starts the month in Leo, later moving down into Virgo and making a close approach to Eta Virginis on the 21st.
Venus, rising at ~03:30, starts the month dominating the eastern sky before dawn in a close grouping with both Jupiter and Mars as detailed in the highlights above. Its magnitude drops only slightly from -4.4 to -4.2 during the month whilst its angular diameter drops from 22.7 to 17.6 arc seconds. But, as the illuminated disk increases from 54% to 63% at the same time, the observed magnitude stays almost constant. Venus is rapidly moving closer to the Sun and will have dropped by around 30 degrees towards the horizon by the end of the month, becoming less prominent. Moving from Leo into Virgo, it passes 0.4 degrees from magnitude 3.6 Beta Virginis on the 13th and less than 0.2 degrees from Eta Virginis on the 21st.
Haritina Mogosanu from the Carter Observatory in New Zealand tells us about the southern hemisphere night sky during November 2015. Click here for the full, fantastic transcript of her starrytelling. In this month's Night Sky South, the music you will hear was very kindly provided by brilliant New Zealand composer Rhian Sheehan, who among other projects has produced music for over a dozen UK and US produced Planetarium films. You may even have heard his handiwork during a Super Bowl commercial or two!
Welcome to November. My name is Haritina Mogosanu and today I am your starryteller from Space Place at Carter Observatory in Aotearoa New Zealand. November is my favourite month of the year. The name of November comes from Latin, it means the ninth. It was the ninth month after the beginning of the year, in March.November is the time when the starcluster that we know as the Pleiades is visible again, but on the evening sky. In the Northern part of the world November is a month of contrasts. Too dark, too sharp, frost, mud, chernozem, dead forest leaves and the river, is all that I remember was left of life in the Novembers of my childhood.
On the other side of the world, in Aotearoa, New Zealand, where the sea surrounds us from all directions, the sky is darker than dark and the stars are very bright as we prepare for summer. November here is called Orongo, which means the time after the great rain. Orongo is spectacular in Aotearoa. It harbours the most beautiful asterism I have ever seen, the grand canoe.
The people of New Zealand have an ancient tale which tells of how the stars were shining pebbles laid in a lightless sky by a warrior called Tamatereti, who travelled there in this canoe. Read the tale here and continue reading below to find out why the canoe of Tama Rereti, te waka o Tama Rereti, is an important part of the Aotearoa night sky in November.
If you want to see the canoe from this tale, start from where the Sun has set. There is the Scorpion which represents the prow of the canoe and the sting of it is the beautifully carved wood above the bow of the canoe. A short distance below this is the star at the end of the Scorpion's curving tail that marks the place where the bow meets the water. The curve of the Scorpion's tail and body sinks into the waters of the Milky Way, which at this time of the year surrounds Aotearoa like a beautiful glistening river. As water waves move along the side of the canoe, the bright, orange star, Antares, marks the crest of a wave as the great waka rides at anchor.
From the bow, the anchor rope is marked by Alpha Centauri, the third brightest star in the sky, and Beta Centauri, which are also known as the Pointers of the southern cross. The Southern Cross represents the great stone anchor that that keeps the canoe from the tale in its place, to remind the people of New Zealand how the stars and Milky Way were placed in the night sky so long ago. A tall mast rises from the canoe all the way to the star Achernar, which marks in the Northern World the end of the river Eridanus. The two beautiful galaxies that we know as the Magellanic Clouds are the sails of the waka.
Atutahi, also known as Canopus, is the second brightest star in the sky and is the chief of all stars as well as the navigator of the canoe. Orion makes the stern post, it is elaborately carved and it goes all the way from Betelgeuse, a red-giant star, to high above the water - marked by Rigel, a bluish supergiant star, directly above the line of three stars. From the top of the stern post there is a ribbon of flax blowing out in the wind. At the tip of it, is orange Aldebaran. The flax is the Hyades cluster. Still further left is the Pleiades, which at this time of the year are only making the feathers that adorn the canoe floating on the ripples left behind by the waka o tamarereti. Matariki, the name that the Maori sometimes give to this cluster, is only a memory of winter, as the cluster is only called so in the morning of July when it is wintertime here and it marks the Maori new year. Still six stars are visible to the eye; dozens are seen in binoculars. The cluster is 440 light years away and around 70 million years old.
On the opposite side of the sky to Alpha Centauri and Canopus-Atutahi, the great square of Pegasus is riding the Northern horizon. Not only can see the three brightest stars in the sky at the same time in Aotearoa, New Zealand , we can also see the most prominent four galaxies of our world with the naked eye: The Milky Way, the Magellanic Clouds and very low in the north is the Andromeda Galaxy, easily seen with binoculars in a dark sky and faintly visible to the eye. It appears as a spindle of light.
Saturn is the only naked-eye planet in the evening sky. It sets in the southwest two hours after the sun at the beginning of the month. It looks like a medium-bright creamy-white star directly below orange Antares, the brightest star in the Scorpion. Because it is low in the sky it will look rather fuzzy in a telescope. By mid-month it is disappearing in the dusk.
Venus, Mars and Jupiter are in the eastern dawn sky. The three planets are close together at the beginning of the month, rising after 4 a.m. Venus is brightest, with Jupiter a close second. Mars is a fainter red 'star', just below Venus. The goddess of beauty Venus and the god of war Mars have a brief encounter on the beginning of November, what we earthlings call a conjunction.
This concludes our Jodcast for November 2015 at space place at carter observatory. As the Maori say: E whiti ana nga whetu o te Rangi (the stars are shining in the sky) ko takoto ake nei ko Papatuanuku (whilst Mother Earth lays beneath).
Kia Kaha and clear skies from the Space Place at Carter Observatory in Aotearoa, New Zealand.
Odds and Ends
Asteroid 2015 TB145 made a flyby of Earth on Halloween at only 1.3 times average distance to the Moon. TB145 is ~600 metres in diameter and orbits the Sun once every 3 years or so. Although not visible to the unaided eye, it was observable with a small telescope but would have been a tricky target for amateur astronomers due to glare from the Moon. Although not a threat to the Earth in any way, this object (which bears an uncanny resemblance to a skull) was discovered only weeks before closest approach which highlights our vulnerability to space rocks as we can't often see them coming. Fortunately, there are great efforts underway to detect Earth-crossing asteroids and we should have most city-killers detected by 2025 - giving us ample time to move any on potentially dangerous trajectories into safer orbits.
The piece of space junk WT1190F was recently detected by researchers at the University of Arizona, Tucson, working on the Catalina Sky Survey (CSS). This curious object is between 1 and 2 meters in size and its trajectory indicates that it may be hollow- scientists aren't sure what to make of it just yet, though suggestions include a spent rocket stage or panelling discarded from a recent Moon mission. One thing we are certain though: it is on a collision course with Earth! But there's no need to panic- most of the debris will burn up during atmospheric entry, and any that doesn't will impact the Indian Ocean south of Sri Lanka on Friday November 13th. Any particularly unlucky Jodcast listeners may wish to avoid swimming on that day!
One of the instruments on the Rosetta spacecraft has detected molecular oxygen in the gas vented from Comet 67P (Churyumov-Gerasimenko). This is surprising given that, except for Earth, molecular oxygen has been detected hardly anywhere else either within or outside the Solar System. Moreover, molecular oxygen readily reacts with other atoms and molecules found in space, so oxygen would not be expected to exist in its molecular state for any length of time. The best explanation for why the comet contains molecular oxygen is that it was present when the comet formed in the primordial Solar Systems and that it was trapped in the ice within the comet. More details are provided in the ESA press release.
|Interview:||Dr. Caroline D'Angelo, Alex Clarke and Charlie Walker|
|Night sky:||Ian Morison and Haritina Mogosanu|
|Night Sky South Music:||Rhian Sheehan|
|Presenters:||Charlie Walker, Benjamin Shaw and George Bendo|
|Editors:||Benjamin Shaw, James Bamber, Alex Clarke, Haritina Mogosanu and Charlie Walker|
|Segment Voice:||Kerry Hebden|
|Website:||Saarah Nakhuda, Charlie Walker and Stuart Lowe|
|Cover art:||The dead comet TB145, which flew past Earth on Halloween 2015 and bears an uncanny resemblence to a skull CREDIT: NASA/NAIC-Arecibo/NSF|