June 2019: Milky way mergers, moon mining and mice

In the show this time, we talk to Stephane Corbel about the Nancay observatory, Emma Alexander rounds up the latest news, and we find out what we can see in the June night sky from Ian Morison, Haritina Mogosanu and Samuel Leske.

The News

This month in the news: a star from far, far away, Moon news a-plenty, and updates from the New Horizon spacecraft's flyby of MU69.

First up, news that a star in our Milky Way Galaxy may not be as local as it first appears. A recent paper published in the journal Nature Astronomy by Xing et al. (open access copy here) has shown that the star, named J1124+4535, has an unusual chemistry more typical of nearby dwarf galaxies than our own. The magnitude 14 star, which is located in the constellation of Ursa Major, lies around 60,000 light-years from Earth, and was the target of a study by the Japanese Subaru Telescope.

The star was found to have unusually low levels of metals such as magnesium, but unexpectedly high levels of the heavy element europium. This elemental signature is very different to its neighbouring stars, suggesting that it might be an interloper. In general, stellar neighbours have usually formed from the same building block materials, and consist of similar chemical makeups to each other. J1124+4535's chemical makeup is much more similar to stars within the dwarf galaxies which orbit our Milky Way galaxy than our galaxy itself. Indeed, previous studies have found that the Milky Way formed by colliding with and absorbing smaller galaxies, but this new study has said it provides "the clearest chemical signature" yet of these formative galaxy mergers.

Next, we look a bit closer to home at our closest astronomical neighbour: the Moon. Firstly, there is the news that a new analysis of data from the Apollo missions has shed new light on potential lunar tectonic activity. Small shakes were found to occur on the Moon by detectors placed there by Apollo astronauts, but it wasn't clear if these were caused by the Moon itself, or external forces like meteor strikes. Now, it's been found that the epicentres of 8 of these moonquakes can be traced to within 20 miles of lunar scarps, which are fault lines that can be seen stretching over the lunar surface. The study by Watters et al. was published in the journal Nature Geoscience.

On the other side of the Moon to where the Apollo missions landed, the Chinese Chang'e-4 mission currently has the Yutu-2 rover exploring the landscape of the South-Pole Aitken basin. The basin the largest, deepest, and oldest impact crater on the Moon. This means it provides a valuable insight into the iron and magnesium rich layer of rock underneath the Moon's outer crust, called the mantle. A study published last month in Nature by Li et al. reports that materials rich in iron and magnesium have been found within the crater, and although it's not certain, they could be materials from the mantle, supporting current ideas of lunar formation and composition. It is thought that sometime early in Earth's history, we collided with another planetary body, releasing material which eventually formed the Moon. It doesn't account for the fact that the far side of the Moon has a thicker crust than the near side, but another recent study may just explain it.

Zhu et al. report in the Journal of Geophysical Research that this difference may be due to another collision of planetary bodies - this one between the cooled & solidified Moon and something just a bit smaller the dwarf planet Ceres. The team ran 360 simulations of different models, two of which ending up matching what we actually see in real life. They both involved a collision between the near side of the Moon and an approximately 500 mile wide object travelling between 14-15 thousand miles an hour. Both of these simulated collisions released debris that eventually rained back down on the lunar surface, but over on the far side, forming a layer 3 to 6 miles thick, which matches observations.

And finally, the first peer-reviewed scientific results have been released from New Horizon's New Years Day flyby of 2014 MU₆₉. 4 billion miles from Earth in the Kuiper belt, MU₆₉, nicknamed Ultima Thule, is the farthest ever object to have been visited by us. And ever since the data from the flyby started to be transmitted back to us on Earth, the New Horizons team have been working on its interpretation. They recently reported in the journal Science details of MU₆₉'s development, geology and composition. As suspected from the early images, it is a contact binary object, meaning that it formed from two separate objects that came together to make its iconic peanut shape. It is a lot flatter than anticipated, and the surface has features such as bright spots and patches, hills and troughs, and craters and pits. The largest depression is a 5-mile-wide impact crater. However, the surface on the whole is fairly smooth, implying that MU₆₉ has had a relatively calm history with few violent collisions. Its red colour is believed to be caused by modified organic materials. With still yet more data to be downloaded from New Horizons (the downlink won't be complete for at least another year) there is still lots to learn about this distant object.

Interview with Stephane Corbel

Stephane Corbel gives a brief outline of the Nancay Observatory. Located in the middle of a forest in the Sologne area, some 80 km South of Orleans (or 250 km from Paris) and created in 1953 the Nancay Radio Astronomy Facility is jointly operated by the Paris Observatory, the CNRS, and the University of Orleans. The observatory has three major instruments on site with two more being developed. Stephane also talks about his own research interests and his time in Manchester.

The Night Sky

Northern Hemisphere

Ian Morison tells us what we can see in the Northern Hemisphere night sky during June 2019.

The Planets

• Jupiter, shining at magnitude -2.6 throughout the month, reaches opposition on June 10th and is thus visible throughout the night. Its angular size is 46 arc seconds across. Jupiter lies in the south of Ophiuchus up and to the left of Antares in Scorpius. A highlight gives the times when the Great Red Spot faces the Earth. Sadly it is heading towards the southernmost part of the ecliptic so, as it crosses the meridian, it will only have an elevation of ~14 degrees (Central UK). Atmospheric dispersion will thus take its toll and an atmospheric dispersion corrector would greatly help to improve our views of the giant planet.
  
  
• Saturn, shining with a magnitude increasing from +0.3 to +0.1 during the month, rises around 22:00 UT at the beginning of June so crosses the meridian in the early hours of the morning. By month's end it rises around 21:00 UT. It is moving towards opposition on July 9th. Its disk is ~18 arc seconds across and its rings - which are still nicely tilted from the line of sight - spanning some 40 arc seconds across. Sadly, now in Sagittarius and lying on the southern side of the milky way, is at the lowest point of the ecliptic and will only reach an elevation of ~14 degrees. As with Jupiter, an atmospheric dispersion corrector will help improve our view.
  
  
• Mercury, following its passage through superior conjunction (behind the Sun) on May 21st, is now visible, low in the north-west after sunset. As it moves towards greatest elongation east on June 23rd it rises higher in the sky after sunset, however though starting the month at magnitude -1.1, this falls to magnitude +0.1 by the 17th and falls to +0.9 by month's end. Its angular size increases from 5.5 to 9.2 arc seconds as the month progresses. To spot it, one will need a very low horizon and binoculars could well be needed to reduce the Sun's background glare, but please do not use them until after the Sun has set.
  
  
• Mars, remains at magnitude +1.8 magnitude all month and is still visible in the south western sky after sunset. Initially in Gemini, it moves into Cancer on the 28th of the month. Mars sets some two hours after the Sun at the start of June (with an elevation as darkness falls of ~11 degrees) but by less than one hour by month's end. Its angular size falls from 3.9 arc seconds to 3.7 arc seconds by month’s end so one will not be able to spot any details on its salmon-pink surface.
  
  
• Venus, with a magnitude of -3.8 rises just one hour before the Sun this month with its angular size reducing from 10.5 to 9.9 arc seconds as it moves away from the Earth. However, at the same time, the percentage illuminated disk (its phase) increases from 94% to 98% - which is why the brightness remains constant at -3.8 magnitudes. Its elevation is only ~4 degrees at sunrise so a very low horizon just north of east is required and binoculars may well be needed to spot it through the Sun's glare - but please do not use them after the Sun has risen.
  
  

Highlights

• June 5th - after sunset: Mars close to a very thin crescent Moon. Given a low horizon looking towards northwest after sunset one should, if clear, be able to spot Mars lying over to the left of a very thin crescent Moon.
  
  
• June 8th - after sunset: The Moon in Leo. Looking west in the evening a waxing crescent Moon will be seen lying above Regulus in Leo.
  
  
• June 15th - late evening: Jupiter near the Moon. Around Midnight, Jupiter will be seen over to the right of a Moon coming up to full.
  
  
• June 19th - midnight: Saturn and the Moon. During the night of the 19th June Saturn will be seen up to the left of the Moon, just before full.
  
  
• June 27th - after sunset: Mars and Mercury. After sunset given a low horizon in the northwest you may be able to spot Mars and Mercury together down to the left of Castor and Pollux in Gemini. Binoculars may well be needed but please do not use them until after the Sun has set.
  
  
• June: Look for the Great Red Spot on Jupiter.
  
  
• June 10th evening: Mons Piton and Cassini. Best seen after First Quarter, Mons Piton is an isolated lunar mountain located in the eastern part of Mare Imbrium, south-east of the crater Plato and west of the crater Cassini. It has a diameter of 25 km and a height of 2.3 km. Its height was determined by the length of the shadow it casts. Cassini is a 57km crater that has been flooded with lava. The crater floor has then been impacted many times and holds within its borders two significant craters, Cassini A, the larger and Cassini B. North of Mons Piton can be seen a rift through the Alpine Mountains (Montes Alpes). Around 166 km long it has a thin rille along its center. I have never seen it but have been able to image it as seen in the lunar section.
  
  

Southern Hemisphere

Haritina Mogosanu and Samuel Leske from the Carter Science Centre in New Zealand speaks about the Southern Hemisphere night sky during June 2019.

• Meteor Showers. Certain meteor showers take place in June. The Arietids takes place May 22 to July 2 each year, and peaks on June 7. The Beta Taurids June 5 to July 18. The issue with those is that the Sun is very close to the two constellations, Aries and Taurus and also you will have to wake up very early in the morning to watch them providing you have a good horizon. The June Bootids take place roughly between 26 June and 2 July each year. Bootes is grazing the northern horizon in Wellington.
  
  
• What’s the Sun up to? The Sun rises from 7:30 to 7:50AM throughout the month and sets at about 5:00 PM throughout the month. Beautiful and long nights are here but so is cold weather. In the meantime we are basking in 32 degrees in the Sun in the Northern Hemisphere. In June, the Sun first transits the zodiacal constellations of Taurus switching to Gemeni on the 23rd of June.
  
  
• The Milky Way We are now looking towards the centre of our galaxy, which rises in the South East just after sunset and reaches meridian around midnight in the middle of the month.
  
  
• Bright stars in the Milky Way Starting from the West after sunset Betelgeuse is slowly sinking into the Sun and it will be gone from the evening sky towards the middle of the month. In zig-zag to the North is Procyon, the Little Dog alpha star. Zig-zagging again is Sirius, the big dog, and Adhara. Suhail al Muhlif is shining in Vela and Avior, Aspidiske and Miaplacidus are bright stars in Carina. The beautiful stars of the Southern Cross follow the two pointers, Alpha and Beta Centauri.Later on in the night after the centre of the Milky Way rises, is Antares and Shaula in Scorpius, Nunki in Sagittarius and last but not least, after midnight, Altair and Vega are grazing the northern horizon with their beauty.
  
  
• Orion and Scorpius Orion is very close to Taurus and it will sink further towards the horizon as the month progresses. Enjoy it while it lasts, for the rest of this month it will disappear from our sight mid-June.
  
  
• Bright stars on the ecliptic Regulus in Leo (which is extremely close to the ecliptic) and Spica, the blue giant in Virgo are great shiny stars, also Zubenelgenubi, another star grazing the ecliptic and Zubeneschamali just beneath it. Zubenelgenubi means the northern claw and Zubeneschamali the southern claw, alluding to these two stars that have been the claws of Scorpius before they were chopped off and turned into the current constellation of Libra. They are followed by Antares which is the last very bright star visible on the ecliptic before sunrise.
  
  
• Circumpolar Objects to New Zealand The beautiful Southern Cross and the pointers are high in the sky at sunset. Gacrux and Acrux are crossing the meridian around around 7 PM in the middle of the month. Omega Centauri is in a great position to observe, as well as Musca, Vela, Carina and their Diamond Cross, and False Cross and the Large Magellanic Cloud and its Tarantula Nebula.
  
  
• Binocular Objects in June Binoculars come in many shapes and forms, a great size for stargazing is 7 x 50 or 10 x 50. The first number is a measure of power, it means how much these binoculars magnify, in this case the 7 and the 10. The second number is the diameter of the objective (the big lenses at the front) in millimetres, in this case the 50. We really like binoculars because they are light, you can take them easily with you on trips, they don’t really require assembly and disassembly, no polar alignment, and visually are better than telescopes! With a tripod attached they are truly magnificent. Comets and some open star clusters are sometimes better observed with binoculars. We have two eyes, so binocular views are more spectacular in many regards than telescopic, because our brains interpret what we see, binoculars give depth of view as they engage both eyes in the process. There are a few great objects that you could admire in binoculars. You can get a map and look for all these objects. Or, if everything else fails, simply take your binoculars and swipe the Milky Way from one edge to the other. You might not figure out exactly which objects you are looking at but you would definitely find amazing sights, especially in the region close to Carina. You will find there IC2602, NGC3114, NGC353, NGC2516 that are all open clusters then in Crux NGC4755 which is another open cluster, NGC2451 in Puppis, and IC2391 in Vela. Lower down, Omega Centauri, is a globular cluster in Centaurus and in Scorpius, there are the Butterfly Cluster, M7 open cluster and NGC6231 open cluster.
  
  
• Telescope Objects in June A fantastic night in central Wellington where the Large Magellanic Cloud is only visible with averted vision, still, not bad for a capital city. We looked at the Southern Beehive NGC 2516, Gem Cluster NGC 3293, Southern Pleiades IC 2602, Wishing Well NGC 3532, Jewel Box NGC 4755, Omicron Velorum IC 2391, Omega Centauri NGC 5139, Alpha Centauri and Acrux, Tarantula NGC 2070.
  
  
• Planets From the start of the month Jupiter's position just keeps getting better and better. At the start of the month it rises about 5:30 in the very early evening and by the end of the month it’s already a third of the way up the sky by that time. The best thing is that you won’t have to stay up too late to get the best views of Jupiter at the end of the month because the planet will be nearly straight up from around 10:30pm. With the minimum amount of atmosphere to look through you should see some fantastic detail on the planet and those who are into imaging the gas giant may be able to capture some of the activity that is going on with the Great Red Spot at the moment - which may have to change it’s name to the Mediocre Red Spot. The Moon and Pluto have a visually close encounter at 10pm also on the 19th June. Good luck seeing it though given the huge difference in brightness of the two celestial objects.
  
  

Odds and Ends

A recent study has seen mice on board the ISS to investigate the effects of long-term spaceflight, investigating how their physical well-being and behaviour compares to mice on the ground. Mice of two age groups – 16 weeks and 32 weeks – were kept onboard the ISS for up to a month, the equivalent of a long-haul mission of several years in humans.

Overall, the study saw that the 'mousetronauts' behaved very similarly to the control group on the ground. They still spent a normal amount of time eating, grooming, and exercising, and were active during the habitat’s artificial night cycle as they would be on Earth. One unusual behaviour starting happening, though: the younger group of mice began running laps on the cage walls. It began with just a few mice running a single loop around the cage, but over time they began to run multiple loops, and it became a group activity. Interestingly, this was almost exclusively done by the younger mice.

There are a few reasons this might’ve happened. The stressful experience of being launched to the ISS and living in microgravity could be one reason, with the "looping" behaviour being like big cats pacing in a small enclosure. It might also have been a way that the mice could counteract the effects of microgravity on their sense of balance. Boredom shouldn’t be discounted either – because it had to be sent to space, the mice’s enclosure wasn’t very decorated, and they may have started running because it was a way to pass the time, as mice on the ground will do in wheels. However, even wild mice run in wheels, so it’s not necessarily a stress or boredom response – it might simply be for fun! Running like this could give the mice an exercise-induced dopamine boost; rather than getting it from climbing and exploring as they might on Earth, they could be taking advantage of microgravity to exercise in a new way. This does align with only the younger mice taking part – mice tend to exercise less as they get older.

Regardless of the cause, it’s certainly something to see – if you’re curious, have a look here.

On the 24th of May the American Aerospace company SpaceX launched 60 satellites into Low-Earth Orbit (LEO). Videos have emerged of the satellite train easily visible with the naked eye. Many researchers have expressed concern about the possible impact on ground-based astronomy of SpaceX's Starlink project, which could place as many as 12,000 satellites in orbit by 2027. You can read the International Astronomical Union's statement on the matter here.

We need to talk about space mining – as NASA gears up to send humans back to the Moon, both space agencies and private companies are looking at the Moon as a source of great potential wealth, harbouring water reserves and precious metals such as platinum. A recent 180-page report (at previous link) details how water could be extracted from the Moon to supply a lunar rocket fuelling station, and the obstacles that would need to be overcome to do this.

Another recent paper is more cautious, advising that humans should only initially exploit 1/8th of the resources available to us, leaving the rest as space wilderness, in order to avoid humanity running through its available resources too quickly. As the prospect of a true “space economy” becomes more real, these difficult conversations and decisions need to be taken sooner rather than later - such ventures promise great wealth, but also tremendous risk, as current laws and treaties governing the exploitation of space are dangerously weak.

We also take some time to mark the handing over of the show to a new set of show runners - Mike, Tiaan and Fiona. We hope you'll keep on Jodding with us!

Show Credits

News:	Emma Alexander
Interview:	Stephane Corbel, Tom Scragg and Michael Wright
Night sky:	Ian Morison and Haritina Mogosanu
Presenters:	Jake Staberg Morgan, Fiona Porter and Tiaan Bezuidenhout
Editors:	Adam Avison, Naomi Asabre Frimpong, Elizabeth Lee, Tom Scragg and Hongming Tang
Segment Voice:	Tess Jaffe
Website:	Michael Wright and Stuart Lowe
Producer:	Michael Wright
Cover art:	The far side of the Moon photographed by Apollo 16, April 1972 CREDIT: NASA Apollo 16 photograph AS16-3021