We need to go faster. In the show this time, we talk to Professor Vik Dhillon about high-speed astronomy, Mat rounds up the latest news, and we find out what we can see in the October night sky from Ian Morison and Claire Bretherton.
The Rosetta spacecraft has reached its final resting place on the surface of the comet 67P/Churyomov-Gerasimenko, after planned crash on Friday 30th September 2016.
Launched to space more than 12 years ago, the main aim of the mission was to study comets, which are believed to remain almost unchanged since the beginning of our Solar System, some 4-5 billion years ago, therefore providing a unique insight into its history and evolution. Getting to the 67P was not an easy task, and the whole endeavour was under threat from every direction from the very beginning. The launch of the spacecraft was delayed, by more than a year, due to technical difficulties with ESA's Ariane 5 rocket. As a result of this delay, the original destination, comet 46P/Wirtanen, had to be abandoned and 67P was chosen instead. The spacecraft underwent 4 risky gravity assist manoeuvres, that allowed it to achieve the velocity necessary for reaching its destination, far beyond the orbit of Mars. During its journey throughout the Solar system, Rosetta visited two asteroids: 2867 Steins and 21 Lutetia. Both of these encounters were used to apply small corrections to the spacecraft's trajectory and to test and fine-tune the on-board instruments. On the 6th August 2014 Rosetta finally reached its destination in the neighbourhood of the comet 67P/Churyomov-Gerasimenko. After a series of complicated orbital manoeuvres, it entered the proper orbit around the comet on 10th September 2014, becoming first ever space probe to orbit a comet.
The mission made headlines again couple of months later on 12th November, when the lander Philae detached from Rosetta and became the first man-made object to successfully land on the surface of the comet. Unfortunately the landing was not as smooth as everyone had hoped for and after two harpoons that were meant to anchor the lander and downward-pushing thruster both failed to fire, Philae bounced off the surface of 67P twice and landed in the shadow of a crater. This meant a limited amount of sunlight was able to reach the lander's solar panels, severely limiting its capabilities. With the scientific operations planned to last at least couple of weeks, Philae was able to gather data for only about 57 hours, before the communication was lost. Thanks to the on-board battery, designed to last around two days, the primary scientific operations were completed nevertheless, with data from all 10 scientific instruments on board the lander successfully transferred to Earth.
After long period of silence, communication with the lander was re-established on 13th June 2015 and lasted about a month, until 9th July, when Philae became silent again. That was the last time scientists and engineers at the European Space Agency were able to talk to the "The Little Lander that Could". On the 27th July 2016, the interface used for communications between Philae and Rosetta was switched off, brining the end to the little lander's mission. On the 2nd September the lander was successfully photographed by the Rosetta spacecraft for the first time. Images sent back to Earth, explain why Philae was not able to perform its duties for longer than a bit more than 2 days. The lander was found to be wedged against a large formation and covered in the shadow. With 67P getting further away from the Sun every day, the lack of sufficient amount of sunlight that would allow Rosetta to perform its scientific duties was becoming an issue. If left on its own, the spacecraft would eventually run out of power and either crash onto the surface of the comet, with scientists having no control over its descent trajectory and not being able to gather and receive any useful data, or become a free-floating object in our Solar System, becoming another piece of space junk. It was therefore decided that a controlled crash onto the surface of the comet would be the best solution. During the descent Rosetta would be able to collect valuable data and send it back to Earth.
On the 30th September, the probe crash-landed onto the 67P. Although it approached the surface at speeds not exceeding 1 metre per second for most of the descent, the probe was most probably badly damaged and the signal from the spacecraft was lost around noon UK time. As it approached the surface of the comet, Rosetta instruments were kept busy, analysing gas and dust as well as taking multiple high-resolution pictures. Even though the mission encountered some problems along the way, scientists are still pouring through massive amount of data that both Rosetta and Philae sent back to Earth. Although it will take at leasy few more years to interpret all of it, the preliminary results, confirm that comets are indeed more than 4 billion years old and therefore come from the times of Solar System formation and its early evolution. Organic molecules were found by both Rosetta and Philae. This provides evidence for the theory that some of the organic compounds were brought to the surface of the Earth through collisions with comets during the early stages of the Solar System's existence. The European Space Agency was also very successful in engaging and informing the public about the mission and its findings. The mission gained a lot of media coverage from major news outlets, sometimes unfortunately for not scientific reasons. With a series of cartoons and animated videos, ESA is hoping to inspire younger members of the public, to become future scientists and engineers, that maybe one day will launch another successful mission that will explore the history of the Sun and the planets around it.
Elon Musk, the founder and CEO of SpaceX, took the stage on Tuesday 27th September, when he announced his plans for the colonisation of Mars and the outer Solar System, during the International Astronautical Congress in Guadalajara, Mexico.
This is the second time the company made headlines in the last few weeks, after one if its Falcon 9 rocket was lost in the explosion during the September 1st test fire. Even though this is the second rocket lost by SpaceX in the last 15 months and the cause of the most recent incident is not know even a month later, the company and its CEO do not seem to stop. Mars has been a destination for the potential human colony since at least the Apollo-era space programme. The progress however has been slow, and no human has been further than the Low Earth Orbit since the last landing on the Moon in 1972. However, things may change in the next decade.
During his talk, Musk shared his vision for the manned exploration of Mars and beyond. It would be based on a new rocket the company is currently designing, the Interplanetary Transport System. This 122-m tall spacecraft, is meant to be powered by 42 Raptor engines, which are expected to provide more than 3 times the thrust generated by the Saturn V rocket. The whole design is based around the reusability, which is expected to bring the lunch costs down to the manageable levels. The 50-m tall interplanetary spaceship, capable of carrying 100 explorers to the surface of Mars, would be launched to the Earth's orbit on top of the reusable booster. The booster would then return back to Earth and be prepared for another launch. In the meantime, the spaceship would be refilled in-orbit using a tanker delivered by another reusable booster. The whole cycle would repeat again.
Full reusability is expected to bring the launch price to around $200,000 per person, which would represent a huge saving as compared to an estimated cost of at least tens of millions of dollars per person with the NASA's planned Space Launch System. Members of the private and government space sector including Boeing's CEO Dennis Luilenburg, Blue Origin's CEO and founder Jeff Bezos and various members of the US Congress, as well as members of the public, raised a lot of questions regarding the feasibility of these ambitious plans.
The main concern and so far great unknown are funding sources and possibilities for this multi-billion project. SpaceX's estimated budget for its ambitious plans is around $10 billion dollars to develop and build the first rocket. Some industry experts however, have already warned that the real cost might be as much as 2-3 times higher that that. The company also relies quite heavily on funding from NASA at the moment, through various contracts for delivery of goods and ultimately humans to the International Space Station.
The future of this relationship became a great unknown as NASA is investing a lot of time and money into the development of its Space Launch System which is ultimately meant to carry humans to Mars and may see Musk's ITS as a direct competition. With the first launch planned for 2024, only 8 years from now, the company needs to start looking for serious investors and support, both in private sector and government.
Despite all the obstacles, uncertain future and recent setbacks with the flagship Falcon 9 rocket the work is already under way. The company is investing millions of dollars every year into technologies that will eventually be used in the Interplanetary Transport Systems. Two days before his presentation, Elon Musk had announced the first successful firing of the new Raptor engine, and during his speech he revealed pictures of new liquid oxygen tank made out of carbon fibre composites. Even with all developments, it is quite unlikely that the company will meet its 2024 deadline and few years of delays are expected. Elon Musk himself acknowledged that this would be a very difficult, almost impossible task. And if establishing the first Marian colony in about a decade from now does not sound ambitious enough, Musk shared his vision of colonising the outer Solar System with his new rocket, with Saturn's Enceladus and Jupiter's Europa as primary targets.
And if you think that Europa might not be the best destination for the interplanetary colony, think water.
Jupiter's fourth largest moon is believed to harbour a large ocean of liquid water under a thick shell of ice on its surface. New results from the Hubble Space Telescope provide more evidence to support this theory. Scientists from the team led by William Sparks from the Space Telescope Science Institute in Baltimore, believe they have found the evidence of water vapour plumes erupting off the surface of Europa.
This is the second time such plumes have been observed. In 2012, another team, again using the Hubble Space Telescope has found an evidence of water vapour eruptions, shooting into space at a height of more than 150 kilometres. Both teams used the same instrument, the Space Telescope Imaging Spectrograph, but implemented different methods to analyse the data and estimate the amount of material in the plumes and have both arrived at similar conclusions. This shows that Europa can indeed eject large amounts of water vapour from under its thick and solid frozen crust.
This is especially important for future planned unmanned mission to the surface of the Jupiter's moon. One of the biggest engineering challenges is the development of tools that would be capable of drilling through many kilometres of ice in order to reach the liquid ocean underneath and study it, looking for any signs of life. The existence of plumes, which are estimated to eject more than 5000kg of water per second provides scientists with new opportunities to study the depths of the Europa's ocean, without the need to actually drill into the surface.
As the design for the new space probes is now under way, more work has to be done to learn more about the nature of these vapour plumes. Scientists would like to know whether they occur in regular intervals and if they ever repeat in the same place, or if they are rather random and unpredictable events. If they were found to be bound to specific regions on the surface of Europa, then the target selection for the future lander would become much easier.
Interview with Professor Vik Dhillon
Professor Vik Dhillon from the University of Sheffield talks to Monique about observing the high speed Universe. He was involved in building ULTRACAM, which is an instrument which can take images of the night sky every 5 milliseconds. It has travelled the world observing compact phenomena, such as black holes and neutron stars which vary on second or even millisecond scales. More recently, he has been involved with HiPERCAM, which can capture 1000 images per second.
The Night Sky
Ian Morison tells us what we can see in the Northern hemisphere night sky during October 2016.
Highlights of the Month
October - A good month to observe Uranus with a small telescope.
Uranus comes into opposition - when it is nearest the Earth - on the night of the 15th of October, so will be seen well this month - particularly from around the beginning and end of the month when no moonlight will intrude. Its magnitude is +5.9 so Uranus should be easily spotted in binoculars lying in the southern part of Pisces to the east of the Circlet asterism and east-southeast of 4th magnitude stars Epsilon Piscium and Delta Piscium as shown on the chart. It rises to an elevation of ~45 degrees when due south. Given a telescope of 4 inches it should be possible to see that it has a disk (3.6 arc seconds across) which has a pale green-blue tint. With an 8 inch telescope and good seeing, perhaps using a green filter it may even be possible to see some detail in the planet's cloud features which appear to be more prominent than usual. That is an observing challenge! Four of its satellites, Arial(+14.4), Umbrial(+15), Titania (+13.9) and Oberon (+14.1) can also be seen given a night of good seeing and a telescope of 8 inches diameter or more.
October 3rd - after sunset: Venus and a very thin crescent Moon
As twilight fades on the 3rd of October and given clear skies and a very low horizon in the south-west you may be able to spot Venus lying down to the left of a very thin crescent Moon, just 6.7percent illuminated. This gives you a chance of observing 'earthshine', the 'dark' side of the Moon faintly illuminated by light reflected from the Earth.
October 8th, - one hour after sunset: the first quarter Moon lies above Mars
After sunset, looking south and given clear skies, the first quarter Moon will be visible lying up to the left of Mars shining at magnitude +0.15. Mars, in Sagittarius, is lying just to the left of the top star of the Teapot, Lambda Sagittarii.
Observe the International Space Station
Use the link below to find when the space station will be visible in the next few days. In general, the space station can be seen either in the hour or so before dawn or the hour or so after sunset - this is because it is dark and yet the Sun is not too far below the horizon so that it can light up the space station. As the orbit only just gets up the the latitude of the UK it will usually be seen to the south, and is only visible for a minute or so at each sighting. Note that as it is in low-earth orbit the sighting details vary quite considerably across the UK. The NASA website linked to below gives details for several cities in the UK and across the world.
- Jupiter: Jupiter having passed behind the Sun last month, will appear again low above the eastern horizon around the 8th of October. On the 11th, Jupiter at magnitude -1.7 lies close to Mercury but they will only be ~5 degrees above the horizon 30 minutes before sunrise. As the month progreses, Jupiter rises a little earlier so that by month's end and still at magnitude -1.7, it rises some two and a half hours before the Sun. A low eastern horizon and the use of binoculars may well be needed but please do not use them after the Sun has risen. As the Earth moves towards Jupiter, the size of Jupiter's disk increases slightly from 30.6 to 31.2 arc seconds so early risers at the end of the month should be able to observe the equatorial bands in the atmosphere and the four Gallilean moons as they weave their way around it.
- Saturn: On September 11th, Saturn, lying in Ophiuchus, was just 6 degrees above, and a little to the left, of Antares in Scorpius. It is moving slowly eastwards but by October's end will still be only 7 degrees distant. Saturn's brightness stays constant during the month at +0.5 whilst its angular size drops slightly from 15.9 to 15.4 arc seconds. However, the rings are almost at their most open at 26 degrees from edge on and so still make a magnificent sight. Some 20 degrees above the southwestern horizon at the start of October an hour after sunset it will fall then to just 10 degrees by month's end. This is really our last chance to observe it this apparition.
- Mercury: Mercury is just past the peak of its best morning apparition, shining at magnitude -0.8 some 8 degrees above the eastern horizon 45 minutes before sunrise. On the 11th, at magnitude -1.1 it will lie just 0.8 degrees to the left of Jupiter. Its disk then has an angular diameter of 5 arc seconds. Mercury will appear lower each morning becoming lost in the Sun's glare by mid month as it moves towards superior conjunction with the Sun on the 27th.
- Mars: Mars, lying in Sagittarius, reaches its lowest declination (-25 degrees) on October 3rd and so will be seen some 9 degrees above the south-southwestern horizon as twilight ends. Fading from magnitude +0.1 to +0.4 during October, with a disk shrinking to just 8 arc seconds across during the month it will only appear as a featureless salmon-pink object. It starts the month to the lower left of the Lagoon Nebula, M8, and, on the 6th, passes just south of the top star making up the 'Teapot', Lamda Sagittarii. In the last two weeks of October it passes over the Teapot's handle as it moves eastwards across the heavens. It lies closest to the Sun on the 29th.
- Venus: Venus can be viewed low in the southwest after sunset, starting the month in Libra with a magnitude of -3.9. On the 17th, it passes into Scorpius and then, on the 25th, into Ophiuchus. As it does so it will rise a little higher in the sky. But, despite its brightness, binoculars might well be needed to spot it, but please do not use them until after the Sun has set. During the month, its angular size increases from 12 to 14 arc seconds whilst the illuminated percentage of its disk falls from 86 percent to 78 percent. These two factors compensate each other so it brightness stays virtually constant. On the 5th, Venus passes just below the wide double star Alpha Librae whilst on the 20th it passes close to Delta Scorpii which forms part of the scorpion's head.
Martian aurorae - Max learned something interesting about the Martian magnetic field at a conference recently and with Elon Musk's recent announcement it felt appropriate to share. On Earth, aurorae are caused by charged particles from the solar wind becoming trapped by our magnetic field and striking the atmosphere. These particles bounce from pole to pole the produce the Northern/Southern lights. The magnetic field on Mars is much weaker than on Earth since it is no longer supported by a dynamo at the core. All that remains is geomagnetism - magnetically polarised rocks contain the last remnants of the Martian magnetic field. This weak field makes the whole sky a potential contact point with the solar wind, meaning that aurorae could happen anywhere. Due to the interaction between geomagnetism and the solar wind, during strong solar storms only the strongest areas of magnetism can maintain a field above surface level, so you end up with localised magnetic bubbles. Inside these, all sorts of plasma phenomena can occur so you could see some spectacular aurorae! So, if you sign up to become one of Elon's explorers, you can look forward to hunting for aurorae out in the Martian desert. Take a look at Max's suggestion for a good viewing spot on Google Mars and compare it with a magnetic map of Mars to come up with your own suggestions.
The Jodcasters spent three days in early October on a "Jodcast Busy Days". The aim of these days was to take the 10-odd years of experience of making the Jodcast, which is usually passed down from one generation of Jodcast team to the next by word of mouth and making the whole process more efficient, and hopefully less susceptible to delays in getting the show out. In addition to this the team tried to cross off things on the ever growing "big list of things we need to do for the Jodcast", with some success. For example, iTunes users will now notice that the cover-art has been updated. Hopefully you'll notice the difference of this effort in the coming months!
The world as you know it has changed! You are no longer the person you thought you were! A new constellation has been added to the horoscopes and everything you though you knew is wrong. Read more here.
Claire Bretherton from the Space Place Carter Observatory in New Zealand speaks about the Southern hemisphere night sky during October 2016.
Kia ora, and welcome to the October Jodcast from Carter Observatory in Wellington, New Zealand.
October is a good time to look out for the zodiacal light, seen as a triangular glow in the west after sunset in a clear, dark sky. It is caused by light reflecting off dust along the plane of our solar system. This plane is marked by the ecliptic, the apparent path of the Sun across the sky, which runs through the constellations of the zodiac. At this time of year the ecliptic makes a steep angle with the horizon, making the zodiacal light easier to observe.
As our nights are getting lighter and our days warmer our winter zodiac constellation of Scorpius/ te Matau a Maui drops down towards the horizon, taking cream-coloured Saturn with it. Saturn sits to the right of orange Antares, and with its 29.5 year orbit around the Sun, moves very little against the background sky. The pair set shortly before 11pm by the end of the month.
In sharp contrast, Venus, with its 225 day orbit, moves quickly eastwards against the background stars, appearing higher and higher in the western evening sky. By the end of the month it passes between Saturn and Antares, setting over 3 hours after the Sun.
Red Mars is higher still and continues to hold its position well this month, moving through the constellation ofSagittarius and setting after around 2 am. As we move away from Mars on our inner orbit, it is slowly slipping down the sky, and gradually becoming fainter, but it will remain in our evening skies well into the New Year.
If you have a good pair of binoculars or a small telescope, you might want to look for another planet this month. Uranus, the second most distant planet in the Solar System, reaches opposition on Saturday 15th. This is when Uranus lies on the opposite side of Earth to the Sun, reaching its highest point in our skies at around midnight. It is also around this time that Earth and Uranus are at their closest, although this won't make too muchdifference to the planet's brightness from our point of view.
Uranus will be above the horizon for much of the night, shining at magnitude 5.7 in the constellation of Pisces the fishes. On a very dark, clear night it may just be possible to glimpse Uranus with the naked eye, but a full Moon close to the time of opposition will make this impossible at that time. Better to look at either the start or end of the month, closer to the new moon. With binoculars, however, Uranus should be relatively easy to spot, as long as you know where to look, although it will appear as just a star like point of light without the use of a telescope.
A little to the north of Pisces is the constellation of Pegasus, the winged horse, which appears to leap across the northern horizon in our evening sky. Pegasus is easy to spot by the Great Square of stars that makes up his body.
The brightest star in the constellation is the reddish star Epsilon Pegasi, marking the horse's muzzle. This star is commonly known as Enif, deriving from the Arabic word for nose. Epsilon Pegasi is an orange supergiant, around 12 times the mass of the Sun , and with a radius some 185 times larger.
Nearby (and visible in the same binocular field of view) is the globular cluster M15, one of the oldest and best know star clusters in the sky, with an estimated age of around 12 billion years. The cluster is located around 34,000 light years away and measures 175 light years across. M15 is probably the most densely packed globular cluster in our galaxy, with half of its mass concentrated within 10 light years of the centre. It has been suggested that this massive concentration of stars may be caused by a rare type of supermassive Black Hole in the cluster's core.
With binoculars M15 will appear as a fuzzy star, whilst a medium sized or larger telescope will reveal individual stars, particularly towards the outer regions, appearing as chains and streams radiating out from the core.
M15 also contains the planetary nebula Pease 1, the first to be found within a globular cluster. At magnitude 15.5, this is a faint object, and a telescope with an aperture of at least 300mm would be needed to observe it.
The star at the bottom right of the Great Square of Pegasus is in fact Alpha Andromodae, or Alpheratz, the brightest star in the constellation of Andromeda. Located some 97 light years from Earth it is a spectroscopic binary star whose two components orbit each other in just 100 days.
Alpheratz is a great starting point to star hop to the great galaxy in Andromeda, or M31. The nearest large spiral galaxy to our own, M31 makes a rare appearance in our southern hemisphere skies at this time of year, but you'll need a good, dark sky and a clear view of the northern horizon to spot it. The further north you go, the better your chances of finding it.
From Alpheratz look for two chains of stars extending out to the east. Hop along the uppermost, and brightest, of these chains past Delta Andromedae to Mirach (Beta Andromedae), then turn sharp right and head down to Mu Andromedae before jumping on the same distance again to find the galaxy.
The Andromeda galaxy covers an area around 6 times the diameter of the full moon, but only the brighter central region is easily visible to the naked eye, or with binoculars or a small telescope.
At 2.5 million light years away, and magnitude 3.4, it is the most distant object easily visible with the naked eye. Andromeda is thought to contain around one trillion stars, well over twice the number estimated in our own Milky Way. Some recent studies, however, have suggested that the Milky Way may contain more dark matter than Andromeda, giving the two galaxies a similar mass.
M31 is approaching the Milky Way at 110 km/s and is expected to collide and merge with our Galaxy in around 4 billionyears.
A little higher and towards the east, the Triangulum galaxy or M33 is better placed in our skies. At around 3 million light years from Earth and shining at magnitude 5.7 it is just at the limit of naked eye visibility under excellent conditions, making it one of the most distant objects able to be glimpsed unaided. With the mass of 10s of billions of Suns, M33 is the third largest member of the local group. Like the Andromeda galaxy, it is also approaching us, at around 100,000 kilometres per hour.
To find M33, head back from Andromeda towards Mirach and then continue a similar distance to the other side. Whilst M33 with the naked eye is a challenge, it is easily observable in a pair of binoculars.
The most striking feature of the Triangulum Galaxy is a massive region of star formation, known as NGC604, which can be seen with a small telescope. NGC604 is 100 times larger than the Orion Nebula and contains over 200 hot, massive blue stars formed just 3 million years ago. In fact, if it were at the same distance as the Orion Nebula, only the Moon would be brighter in the night time sky.
Of course there are 2 galaxies that are always visible in our night sky, the Large and Small Magellanic clouds, which are circumpolar here in New Zealand. To find the Magellanic Clouds, first look for the bright star Canopus, twinkling colourfully, low in the southeast. The Magellanic clouds appear as two small smudges of light above it, they are irregular dwarf galaxies that neighbour our own. Whilst these galaxies are much smaller than the Milky Way, they still contain hundreds of millions of stars.
The Large Magellanic Cloud, or LMC, is the lower of the two and is located 160,000 light years away. Through binoculars or a small telescope you may be able to spot a number of young star clusters visible as small patches of light. The LMC also contains a massive star formation region, one of the largest and brightest known, called the Tarantula nebula or 30 Doradus. Spanning around 600 light years across, and covering 13 arcminutes in the sky,the Tarantula nebula contains over 800,000 stars and protostars and is the most active starburst region identified within our local group of galaxies. If it were placed at the same distance as the Orion Nebula it would be so bright that it would cast a shadow here on Earth.
The star formation activity within the Tarantula nebula began a few tens of millions of years ago, and some of the largest and brightest stars born within this region have already reached the ends of their short lives. In February 1987 supernova SN1987A was discovered in the outskirts of the Tarantula nebula by astronomers at Las Campanas Observatory in Chile, and independently by prolific amateur astronomer Albert Jones here in New Zealand. This supernova was the closest since the invention of the telescope just over 400 years ago and provided a unique opportunity for astronomers to study such an event in unprecedented detail. Reaching a peak magnitude of around 3, SN1987A was easily bright enough to spot with the naked eye.
Smaller and more distant, at around 200,000 light years, is the Small Magellanic Cloud, or SMC. To the top-right of this galaxy you may spot a faint fuzzy 'star'. This object is not actually associated with the SMC but is a beautiful globular cluster called 47 Tucanae, or NGC 104, and is actually located just a tenth of the distance away on the outskirts of our own galaxy. At magnitude 4.9 it is the second brightest globular cluster in the sky, after Omega Centauri, and can be easily seen with the naked eye. With a binoculars or a small telescope it is a wonderful sight, revealing a densely packed central core, whilst a larger telescope will start to resolve some of its millions of ancient stars.
Wishing you clear skies and happy galaxy hunting from the team hear at Space Place at Carter Observatory
Odds and Ends
|Interview:||Professor Vik Dhillon and Monique Henson|
|Night sky:||Ian Morison and Claire Bretherton|
|Presenters:||Fiona Healey, Max Potter, and Adam Avison|
|Editors:||Damien Trinh, Tom Armitage, Claire Bretherton, Tom Scragg, and Charlie Walker|
|Segment Voice:||Kerry Hebden|
|Website:||Charlie Walker, Minnie Mao and Stuart Lowe|
|Cover art:||Placeholdery McPlaceholderface CREDIT: Mateusz Malenta|