Euorpa’s icy, mineral-stained surface as imaged by NASA’s Galileo mission – see below (credit: NASA / JPL)
NASA have been teasing the press and pundits with news that they have a “surprising” announcement to make about Europa, one of Jupiter’s four Galilean moons (so-called as they were first recorded by Galileo Galilei).
Slightly smaller than our own Moon, Europa is covered by shell of water ice, much of it discoloured by mineral deposits and by deep cracks. This icy surface might only be relative thin, on the order of a handful of kilometres in extent, or it might be tens of kilometres thick, and sits over an ocean which is mostly likely liquid water, although some argue it might actually be an icy slush, perhaps extending to 100 km (62.5 miles) in depth.
The ocean is made possible by tidal flexing enacted by the massive gravity of Jupiter as well as from the other large Galilean moons. This generates heat within Europa, and this heat stops the water from freezing solid.
An artist’s impression of how a huge plume of water, over 200km (125 mi) high, which erupted from Europa in 2012 and was “seen” by the Hubble Space Telescope, might have looked like if witnessed from the vicinity of Europa. Credit: NASA / ESA / M. Kornmesser.
Exactly how much heat is generated as a result of this flexing isn’t known, but it has been suggested that the ocean floor could be home to volcanic activity with hydrothermal vents and fumeroles responsible for pumping huge amounts of minerals into the water, as well as supplying energy, potentially marking Europa’s ocean as a place where basic microbial life might arise.
The discovery of life on Europa isn’t going to be the subject of the NASA press conference. It will instead reveal the findings of a Europa observation campaign using the Hubble Space Telescope linked to the potential for a liquid water ocean being present under the moon’s ice. I’ll likely have more next week.
Nor is Europa likely to be alone in harbouring a subsurface ocean among the Galilean moons of Jupiter. In 2015 data from the Hubble Space Telescope confirmed that Jupiter’s largest moon, Ganymede, has an underground ocean that contains more water than all of Earth’s combined. Hubble was used to carry out a spectrographic observation of Ganymede’s aurorae, displays of light in the atmosphere. Because aurorae are controlled by a moon or planet’s magnetic field, observing changes in how they behave offers insights into what is happening beneath the surface of the planet or moon. In Ganymede’s case, the aurorae allowed scientists to confirm a long-suspected subsurface salt water there.
Pluto’s Liquid Heart
A global mosaic of Pluto captured by New Horizons from a distance of 450,000 km (280,00 mi) from Pluto byt New Horizons on July 14th, 2015, coloured from data received by the RALPH instrument on the spacecraft, reveals the planet’s heart-shaped mark, the left “lobe” of which is formed by the massive depression dubbed “Sputnik Planum”. Credit: NASA/JPL / JHU/APL / SwRI
In June, I wrote about a paper proposing Pluto harbouring a liquid water ocean beneath its surface. The paper, by Planetary Science Institute Senior Scientist Amy C. Barr and Noah P. Hammond of Brown University, reached its conclusion after a prolonged study of Pluto’s geological features, including “Sputnik Planum”, a massive depression on the planetoid which forms one “lobe” of Pluto’s distinctive “heart”.
Barr and Hammond’s work focused on the lack of ice II on Pluto – a place where ice II should be expected to form. Had it done so, it would have caused volume contraction, resulting in the formation of compressional tectonic features on the surface of the planet. However, Barr and Hammond found no evidence for such features on Pluto in all of the images returned by the New Horizons spacecraft which flew past Pluto and its twin, Charon, in July 2015. This led them to conclude that Pluto’s interior is warmer than might be expected, which would both prevent ice II from forming and potentially give rise to a liquid ocean beneath Pluto’s frozen crust.
Now, a second paper has been published in Geophysical Research Letters, offering a suggestion as to how deep that ocean is, and its potential composition. Another research team at Brown University have been investigating the dynamics between Pluto and Charon, and the likely formation and development of the “Sputnik Planum” depression, which is thought to have been initially created by the impact of an object some 200 km (125 mi) across at some point in Pluto’s formative years.
Pluto and Charon are tidally locked with each other, so they always show each other the same face as they rotate. “Sputnik Planum” sits directly on the tidal axis linking the two worlds. This suggests the basin has what’s called a positive mass anomaly — it has more mass than average for Pluto’s icy crust. As Charon’s gravity pulls on Pluto, it would pull proportionally more on areas of higher mass, which would tilt the planet until “Sputnik Planum” became aligned with the tidal axis.
The surface ice on “Sputnik Planum” is constantly being renewed both by atmospheric deposition from above, and convection action from below, suggesting a source of heat beneath the ice, which in turn could be keeping any subsurface ocean liquid. Credit: NASA/JPL / JHU/APL / SwRI
But why would a crater – essentially a hole in the ground – be a positive mass anomaly? Part of the answer probably lies in the huge amount of nitrogen ice which has accumulated in the basin over the aeons, adding mass to the basin.
But the ice isn’t thick enough on its own to create the amount of mass needed to make “Sputnik Planum” have positive mass. Water, however, could have sufficient mass.
An impact creates a dent on a planet’s surface, followed by a rebound. That rebound pulls material upward from deep in the planet’s interior. If that material is denser than what was blasted away by the impact, the crater ends up with the same mass as it had before the impact happened. Any material added to it after the impact and rebound would therefore add mass to it, creating a positive mass anomaly.
The moment of destruction: the SpaceX Falcon 9 explodes on Launch Complex 40 at Kennedy Space Centre, Florida
SpaceX Look to Resume Falcon Flights in November 2016
SpaceX President Gwynne Shotwell has indicated the company hopes to resume Falcon 9 launches from November 2016, despite the September 1st loss of the launch vehicle and its US $200 million Amos 6 Israeli-built communications satellite during the preparations for a full static fire test of the rocket’s main engines.
It’s an ambitious aim, given that the cause of the loss is still unknown – and until it is known, it is highly unlikely the Falcon 9 will be cleared for flight by the FAA. However, the comments might suggest company feel that the cause of the loss may not have been with the booster itself, but may have been triggered by an external event, in which case such a target might be possible.
Launch Complex 40, Canaveral Air Force Station, after the Loss of the Falcon 9 booster and payload on September 1st, 2016. Credit: Ken Kremer
The static fire test is a part of pre-launch preparations unique to SpaceX. Basically a full dress rehearsal of a launch, it includes fuelling the booster and briefly firing the main engines with the rocket locked-down on the pad. It was during fuelling operations, eight minutes before the rocket motors were to be fired, the that a series of explosion occurred, destroying the booster and its payload.
Video footage seems to suggest the point of origin for the explosions was outside of the vehicle, in what SpaceX has called a “fast fire”, which started at, or near, the liquid oxygen fuelling umbilical. As well as the complete loss of the vehicle, the explosions and fireball caused extensive damage to Space Launch Complex (SLC) 40 at Canaveral Air Force Station, which had been leased to SpaceX for Falcon 9 launches.
It is the second lost of a Falcon 9 rocket in 15 months. In June 2015, the vehicle carrying the Dragon CRS-7 cargo resupply vehicle to the International Space Station disintegrated a little over two minutes after lift-off, following the failure of an internal strut.
In order to resume launches and meet obligations, SpaceX are planning on pivoting Falcon 9 launches to Kennedy Space Centre’s Pad 39A until such time as SLC 40 can be repaired. SpaceX leased the pad – a part of the complex used to launch the Saturn IB, Saturn V and space shuttles – in 2014 in a 20-year deal. It is currently being refurbished at the company’s expense to launch crewed Dragon 2 flights to the International Space Station, and commercial missions using their new Falcon Heavy launcher. Currently, there is still much work to be completed at the launch complex – previously used to launch the space shuttle, and before that, the mighty Saturn V rocket, although SpaceX plan to have the work completed by November.
Launch Complex 39A at Kennedy Space Centre undergoing refurbishment by SpaceX in preparation for Falcon Heavy and crewed Falcon 9 launches. The Rotating Service Structure, seen on the left and used for space shuttle launches, is due for demolition
Whether or not the root cause of the September 1st accident will be known by then, and the Falcon 9 cleared for flight is a major unknown. The investigations into the June 2015 loss took six months to complete and – due to it being caused by a failure within the vehicle – the rocket had to undergo several engineering changes.
Blue Origin Announces the New Glenn Booster Family
Blue Origin, the company founded by Amazon founder Jeff Bezos, revealed its plans for a family of reusable boosters for both orbital and deep space launches. Called New Glenn, the vehicles are a significant step forward for the company.
The New Glenn family. Credit: Blue Origin
Although more widely known for their efforts in the sub-orbital space tourism field, with their New Shephard reusable system, Blue Origin has long indicated it has wider aspirations, whilst remaining somewhat tight-lipped about exactly what it is developing.
Like the smaller New Shephard sub-orbital launch vehicle, New Glenn is to comprise a reusable first stage – referred to as the “propulsion module” on New Shepard. The vehicle has been under development for about 4 years, and the plan is for the first launch to take place in 2020.
Seven metres (23ft) in diameter, the New Glenn first stage will be powered by seven of the company’s new BE-4 engines. These are the same engines United Launch Alliance have selected as the primary propulsion unit for their own upcoming new Vulcan launch vehicle, which will enter service in 2019 to replace the expensive Atlas V booster.
This core stage of the new Blue Origin rocket – which is named for John Glenn, the first American to orbit the Earth, just as New Shephard is named after Alan Shephard, the country’s first astronaut to fly in space – will be topped by either a second stage for launches to low-Earth orbit, or a combination of a second stage and third stage system capable of a broader range of launch options. In both variants, the second stage will be powered by a single BE-4 engine, while the third stage will be powered by an uprated version of the BE-3 engine, currently used by the New Shephard. Neither the second nor third stages will be recoverable. It is anticipated that New Glenn will be capable of lifting between 35 to 70 tonnes to low Earth orbit, placing it in the same class of launch vehicle as SpaceX’s Falcon Heavy – and thus competing directly with it.
When it enters service, the new booster will be launched from America’s Space Coast, from the historic Space Launch Complex 36 at Canaveral Air Force Station, which Blue Origin took over in September 2015 in a deal with the USAF’s 45th Space Wing.
New Glenn compared to other current launch vehicles. The two-stage variant will be 85 metres (270ft) tall, and the 3-stage variant 95m (313 ft) tall. Both will have a 7m (23 ft) diameter. Credit: Blue Origin
In its time, SLC 36 was was used to launch the Mariner missions, the first US interplanetary probes to visit over worlds, Pioneer 10 and Surveyor-1, the first US vehicle to soft-land on the Moon. It was largely demolished in 2010, leaving just a single pad. Blue Origin are expected to construct a rocket fabrication and assembly facility there, as well as a new launch complex. Currently, it is not clear how the first stage of the booster will be recovered, but the company have hinted at an automated at-sea landing in the style of SpaceX might be used.
China Launches Tiangong-2
On Thursday, September 15th, 2016, and as expected, China launched the Tiangong-2 (“Heavenly Palace 2”) orbital laboratory from their Jiuquan Satellite Launch Centre in Gansu Province, and on the edge of the Gobi Desert in northern China. The Long March 2F booster (and not a long March 7, as incorrectly reported in some space news outlets) lifted-off at 14:04 UTC, making for a night launch, local time.
The Long March 2F carrying the Tiangong-2 orbital laboratory, lifts-off from China’s Jiuquan Satellite Launch Centre in Gansu Province at 14:04 UTC on Thursday, September 15th
Tiangong-2 is the second phase of China’s goal to establish a permanently crewed space station in the early to mid 2020s. This work started in 2011 with the launch of the Tiangong-1 facility, which was briefly visited by two crews in 2012 and 2013. It will culminate in the on-orbit construction of a large space station, starting with the launch of the Tianhe (“Harmony of the Heavens”, and formerly Tiangong-3) space station core module in 2022.
an artist’s impression of Tiangong-2 (centre right) with the Tianzhou resupply vehicle docked (left), together with the Shenzhou-12 crew vehicle at the laboratory’s far docking port. Credit: CCTV
It is expected that at least two crews will visit the facility. The first 2-person crew will fly to the laboratory in October aboard Shenzhou-11. They will commence the first round of a fairly extensive science programme, remaining at the lab for around 30 days.
After this, the facility will be left dormant until April 2017, when a Long March 7 booster is due to deliver the Tianzhou (“Heavenly Ship”) uncrewed resupply vehicle to orbit. This craft will then perform an automated docking with Tiangong-2, providing it with additional fuel, water and other consumables and also use its engine to boost the laboratory into a higher orbit to await the arrival of the second crew.
The second crew, comprising 3 personnel, should fly to the facility in mid-2017 Shenzhou-12. They are expected to say for less than 30 days, but while there carry out a number of tasks connected to developing a full space station, including performing an EVA. Whether further crews will visit the station after this has yet to be determined.
A Billion Stars – A Map to Our Galactic Neighbourhood
The first one billion: a billion stars in our galaxy mapped by distance and brightest – with a few extra-galactic objects shown for good measure. Credit: ESA/Gaia/DPAC
The above image might not look like much, but it is the largest all-sky survey of celestial objects published to date, pinning down the precise position on the sky and the brightness of 1142 million stars in our galaxy.
It is the product of the European Space Agency’s (ESA) Gaia Project, which is approaching the mid-point in its 5-year mission. Launched in December 2013, and orbiting the L2 Lagrange point, Gaia commenced its mapping operation in July 2014 – and it will continue doing so through until 2017. This map, released by the European Space Agency on September 14th, covers the data gathered from July 2014 through to September 2015. A further map, which includes data through to August 2016, is currently in development.
An artist’s impression of the Gaia vehicle at the L2 position relative to the Earth and Sun
The intention is to create a precise three-dimensional map of astronomical objects throughout the Milky Way, mapping their motions, which reflect the origin and subsequent evolution of the galaxy. Spectrophotometric measurements by the craft will provide a detailed survey of all observed stars, characterising their luminosity, effective temperature, gravity and elemental composition. The data gathered will provide the basic observational data to tackle a wide range of important questions related to the origin, structure, and evolutionary history of our galaxy.
It is the second such survey to be undertaken. The first was ESA’s Hipparcos mission, almost two decades ago, which surveyed around 200 million stars. One aspect of the Gaia survey will be to compare its findings with those of Hipparcos, so it will hopefully be possible to start disentangling the effects of “parallax”, a small motion in the apparent position of a star caused by Earth’s yearly revolution around the Sun, and the “proper motion” of the star’s physical movement through the galaxy.
The Gaia map includes globular clusters without our own galaxy, and images of clusters and galaxies beyond our own. Credit: ESA/Gaia/DPAC
The Gaia map means it is now possible to measure the distances and motions of stars in about 400 clusters up to 4,800 light-years away, and includes 3194 variable stars, which rhythmically swell and shrink in size, leading to periodic brightness changes. Many of these are located in the Large Magellanic Cloud, one of our galactic neighbours, a region that was scanned repeatedly during the first month of observations, allowing accurate measurement of their changing brightness. During the first phase of the mission, Gaia also discovered its first supernova in another galaxy, and the science and engineering team had to overcome a “stray light” issue where fibres used in the vehicle’s sun shield protrude beyond the edges of the shield and into the field of view. In doing so, they reflect unwanted light, resulting a degradation in science performance when mapping the faintest of stars in Gaia‘s view.
The Birth of a Black Hole?
Black holes; the boogie-men of the cosmos. Deep wells of gravity so intense that not even light can directly escape after passing the event horizon. They are formed in one of two ways, during the death of super-massive stars.
In the first, the star gobbles up the last of its fusionable fuel, causing the core to suddenly and violently contract, in turn triggering a violent explosion – a supernova – completely shedding the star’s outer shell of mass, and leaving behind a super-dense neutron star. Generally only 10 or so kilometres across, this have a greater mass than our Sun. It is thought that if this mass is too great, the neutron star also collapses in on itself, forming a black hole. In the second, the star doesn’t go supernova, but experiences a “failed supernova” brightening for a very brief period as some matter is lost, but then continuing to collapse in on itself until a black hole is formed. In both cases, the star vanishes from the visible spectrum, leaving behind tell-tale signs in the infra-red and in x-rays.
The Large Binocular Telescope, one of three instruments so far used in gathering data on N6946-BH1. Credit: NASA
A team of astronomers now believe they have captured the birth of a black hole through this second process.
They were studying data relating to N6946-BH1, a red giant thought to be coming to the end of its life, when they noticed something odd. In 2009 the star, roughly 25 times bigger than our Sun and 20 million light years away, could be seen in the visible light wavelengths. By 2015, however, it had vanished, leaving only an infra-red afterglow. A subsequent check on Hubble Space Telescope data revealed the same: in 2007 the star was visible, in 2015, it wasn’t.
Intrigued, the team checked data on the star from the Palomar Transit Factory (PTF). This revealed that in 2009, N6946-BH1 blossomed briefly in luminosity, with a massive burst of neutrinos occurring at the same time – events both consistent with the star collapsing, but not going supernova. Add these to the infra-red tell-tale, and it would seem N6946-BH1 might have formed a black hole.
If so, it should now be a source of x-rays emitted in a particular spectrum as local matter fails into it. The team are now hoping that the Chandra X-ray Observatory in Earth orbit will be able to take a look at N6946-BH1 in the next two months or so to see if those x-rays can be detected. Should it be determined that N6946-BH1 has collapsed into a black Hole – even one now 20 million years old – studying it could help describe the beginning of the life cycle of a black hole, and better inform us on how black holes form, potentially why some super-massive stars form a neutron star rather than collapsing all the way to a black hole.
A dramatic look back: in the foreground is the lower slope of one of the “Murray Buttes”, in the far distance the tall peaks of Gale Crater’s huge rim. One of a series of images taken by NASA’s Curiosity rover on Thursday, September 8th, the rover’s 1,454 sol on Mars. Credit: NASA/JPL / MSSS
NASA’s Mars Science Laboratory rover, Curiosity, has said “farewell” to “Murray Buttes” in a stunning series of images, as it continues its climb up the slopes of “Mount Sharp”, a massive mound of deposited material located at the central impact peak of Gale Crater.
The mesas of “Murray Buttes” mark the upper extend of the transitional “Murray Formation”, where the material deposited during the earliest centuries of “Mount Sharp’s” formation merge with the rock comprising the crater floor. Curiosity has been passing by the area of the buttes for a little over a month now, carrying out examinations of the rock surface and gathering samples of mudstone for analysis.
“Murray Buttes” with the faint outlines of Gale Crater beyond, as images on Thursday, September 8th 2016, by NASA’s Curiosity rover during its 1,454 sol on Mars. Credit: NASA/JPL / MSSS
Believed to be the eroded remnants of ancient sandstone that originated when winds deposited sand after lower “Mount Sharp” had formed, the buttes rival anything of a similar nature found on Earth in terms of dramatic looks and structure. So much so that while we’re hardly likely to see Clint Eastwood ride his horse around the base of one, they would nevertheless fit neatly into a Sergio Leone western.
Several of the pictures – mosaics of images captured by the rover which have been white-balanced to match typical Earth daylight lighting conditions and then stitched together to offer complete scenes – reveal the deeply layered nature of the sandstone, sandwiched in what is referred to as “cross-bedding”. This indicates that the formations are the result of both wind deposition of material and then wind erosion, further confirming the idea that “Mount Sharp” was initially formed as a formed as a result of Gale Crater once being home to a great lake, before the waters receded and wind action took over.
A closer view of the layered nature of the sandstone deposits forming “Murray Buttes”, showing the “cross bedding” of the layers, indicative of the role that wind played in their deposition / formation. This picture comprises a mosaic of images captured by Curiosity rover on Thursday, September 8th, 2016 during its 1,454 sol on Mars. Credit: NASA/JPL / MSSS
The images were taken as Curiosity traversed the base of the final butte, where it gathered a final drilling sample on September 9th. On completion of the sample-gathering, the rover will continue farther south and higher up Mount Sharp, leaving these spectacular formations behind.
Curiosity’s route up the slopes of “Mount Sharp” – click for full size. Credit: T.Reyes / NASA/JPL
The Sand Dunes of Shangri-La
On September 7th, NASA issued a video showing the latest radar images captured by the Cassini probe of the surface of Saturn’s largest moon, mighty Titan. The data was gathered as the probe swept by the huge moon – which is blanketed by a thick atmosphere and is known to have lakes and rivers of liquid hydrocarbons on its surface – at a distance of some 976 km (607 mi) on July 25th, 2016 – one of the closest passes over the moon the vehicle has ever made.
Because of the moon’s thick atmosphere, conventional camera systems cannot be used to probe Titan’s mysteries, so Cassini uses a radar system to “map” surface features in black-and-white. Of particular interest to mission scientists during the July 25th flyby was a dark patch along Titan’s equator, previously images by the radar system at much greater distances and dubbed “Shangri-La”. And area which revealed itself to be – in part – a region of linear dunes, mostly likely comprised of grains derived from hydrocarbons that have settled out of Titan’s atmosphere, and which have been sculpted by Titan’s surface winds. Scientists can use the dunes to learn about winds, the sands they’re composed of, and highs and lows in the landscape.
Also captured by the radar is an arena dubbed “Xanadu annex”, believed to be an out-thrust of chaotic terrain from a region dubbed “Xanadu” just to the north of “Shangri-La”. First imaged by the Hubble Space Telescope in 1994, just before the Cassini / Huygens mission was launched, “Xanadu” and its annex are thought to be remnants of the moon’s icy crust before it was covered by organic sediments from the atmosphere.
OSIRIS-REx Lifts-off as an Asteroid Sweeps By Earth
On Thursday, September 8th, NASA successfully launched OSIRIS-REx on a 7-year trek to reach asteroid Bennu, where it will gather surface samples and return them to Earth for analysis. The mission, which I previewed in my last Space Sunday report, lifted-off flawlessly from Space Launch Complex 41 at Cape Canaveral Air Force Station at 19:05 EDT, atop its Atlas V booster at the start of a journey which will carry it a total of 7.2 billion kilometres (4.5 billion miles).
The Atlas V booster carrying OSIRIS-REx shortly after lift-off on Thursday, September 8th. Credit: Ken Kremer
Witnessing the launch was principal investigator Dante Lauretta, from the University of Arizona. “I can’t tell you how thrilled I was this evening, thinking of the people who played a part in this,” he said following the launch.
“This represents the hopes and dreams and blood, sweat and tears of thousands of people who have been working on this for years.”
The mission will gather samples from the surface of the asteroid – a remnant from the formation of the solar system – and will also map Bennu’s orbit around the Sun and the influences affecting it.
This is because the asteroid is a near-Earth object (NEO): an asteroid which periodically passes across Earth’s orbit around the Sun, and can come very close to our planet whilst doing so. So close, in fact, that some estimates of Bennu’s future orbit suggest it will collide with Earth towards the end of the next century.
Captured at a distance of 78,000 km (48,000 mi) from Jupiter by JunoCam, this image reveals the pale bluish region of Jupiter’s north polar region, speckled by hurricane-like cloud formations. Credit: NASA/JPL / SwRI / MSSS
NASA’s Juno spacecraft has continued to return data and images from its second pass around Jupiter on August 27th, 2016. Images in visible and infra-red light have been received as a part of the data – together with the sound of Jupiter’s “voice”.
Of particular interest are the images of Jupiter’s north pole – which has never been seen by human eyes, and is revealed as being vastly different to the rest of the planet, together with detailed images of the planet’s south pole, only previously briefly seen by the Cassini mission in 2008, whilst en route to Saturn.
“First glimpse of Jupiter’s north pole, and it looks like nothing we have seen or imagined before,” said the Juno mission’s principal investigator Scott Bolton on the release of the most recently received images and data on Friday, September 2nd.
An enhanced view of the north polar hurricane-like clouds images by Juno on August 27th, 2016, together with the blue tingle of the polar atmosphere. Credit: NASA/JPL / SwRI / MSSS
“It’s bluer in colour up there than other parts of the planet, and there are a lot of storms. There is no sign of the latitudinal bands or zone and belts that we are used to—this image is hardly recognisable as Jupiter. We’re seeing signs that the clouds have shadows, possibly indicating that the clouds are at a higher altitude than other features.”
All of Juno’s science instruments were active during the flyby,gathering some 6 Mb of data, images and sounds, which was transmitted back to Earth over a period of a day and a half once the space vehicle had moved away from Jupiter once more. Among this data were images from the Italian-built Jovian Infra-red Auroral Mapper (JIRAM), which returned the first ever close-up infra-red images of Jupiter’s massive aurora.
A mosaic of three infra-red images of Jupiter’s southern aurora taken some 4 hours after the closest point of the flyby. The images were captured by the Jovian Infra-red Auroral Mapper (JIRAM) camera aboard Juno at wavelengths ranging from 3.3 to 3.6 microns — the wavelengths of light emitted by excited hydrogen ions. Credit: NASA/JPL / SwRI / IAPS
“JIRAM is getting under Jupiter’s skin, giving us our first infra-red close-ups of the planet,” said Alberto Adriani, JIRAM co-investigator from Istituto di Astrofisica e Planetologia Spaziali, Rome. “These views of Jupiter’s north and south poles are revealing warm and hot spots that have never been seen before.
“No other instruments, both from Earth or space, have been able to see the southern aurora,” he continued. “Now, with JIRAM, we see that it appears to be very bright and well-structured. The high level of detail in the images will tell us more about the aurora’s morphology and dynamics.”
Juno doesn’t only have eyes, it has ears as well. We’ve known for a long time that Jupiter can be quite “vocal”, and the flyby allowed Juno’s Radio/Plasma Wave Experiment (WAVE) to capture the sound of the planet’s aurorae.
“Jupiter is talking to us in a way only gas-giant worlds can,” said Bill Kurth, co-investigator for WAVE. “We detected the signature emissions of the energetic particles that generate the massive auroras which encircle Jupiter’s north pole. These emissions are the strongest in the solar system. Now we are going to try to figure out where the electrons come from that are generating them.”
Juno is now heading back away from Jupiter on the second of its “long” orbits of the planet. On October 19th, the spacecraft will once again skim over Jupiter’s cloud tops, where it will perform a further braking manoeuvre to reduce its orbital period around the planet to just 14 days.
Did ET Call Us? Mostly Likely Not
The end of August saw various media outlets a-buzz with news about Russian scientists having detected a “strong” radio signal from deep space, with muttering and speculations about aliens, despite cautionary notes from assorted space-related outlets and organisations.
The signal was actually detected in May 2015 by the RATAN-600 radio telescope in Zelenchukskaya, south-western Russia. At the time, the telescope was conducting a survey of astronomical objects in the framework of the SETI (Search for Extraterrestrial Intelligence) programme. It seemed to come from the general direction of the star HD 164595, a star around 95 light years away which is very similar to our own Sun but about 1.5 billion years older, and known to have at least one planet – a gas giant roughly the mass of Neptune – orbiting it.
News about it reached a wider audience in August when a member of the team behind the survey decided to e-mail data on it to colleagues asking for thoughts on what it might be, and suggesting the region of the sky containing HD 164595 should be monitored for further indications of the signal and possible causes.
The RATAN-600 radio telescope. Credit: Russian Academy of Sciences
This request was picked up by science and technology writer Paul Gilster, who blogged about it on his website Centauri Dreams. While Gilster clearly stated there was no evidence of the signal being the work of an extra-terrestrial civilisation, he did couch his post in terms of the power requirements and possible technological status of such a civilisation were the signal to prove to be artificial in nature.
The information was also received by the SETI Institute in California. Their senior astronomer, Seth Shostak, estimated that if transmitting in all directions, the signal would require energy on the order of 10^20 watts – or more energy than the Earth receives from the Sun – making the originating species a Type II civilisation on the Kardashev scale. If directed solely towards Earth, Shostak estimated the energy requirement would “only” be around 10^13 watts – roughly equivalent to all of the energy used by humanity here on Earth, putting the aliens at a Type I civilisation on the Kardashev scale – that is, equal to or slightly more advanced than we are.
An artist’s impression of Proxima b with Proxima Centauri low on the horizon. The double star above and to the right of it is Alpha Centauri A and B. Credit: ESO
On August 15th, I wrote about rumours that an “Earth-like” planet has been found orbiting our nearest stellar neighbour, Proxima Centauri, 4.25 light years away from our own Sun. The news was first leaked by the German weekly magazine, Der Spiegel, which indicated the discovery had been made by a team at the European Southern Observatory’s (ESO) La Silla facility – although ESO refused to comment at the time.
However, during a press conference held on August 24th, ESO did confirm the detection of a rocky planet orbiting Proxima Centauri. Dubbed Proxima b, the planet lies within the so-called “Goldilocks” habitable zone around its parent star – the orbit in which conditions are “just right” for the planet to harbour liquid water and offer the kind of conditions in which life might arise.
Comparing Proxima b with Earth. Credit: Space.com
The ESO data reveals that Proxima b is orbits its parent star at a distance of roughly 7.5 million km (4.7 million miles), at the edge of the habitable zone, and does so every 11.2 terrestrial days and is about 1.3 times as massive as the Earth. The discovery came about by comparing multiple observations of the star over extended periods using two instruments at La Silla to look for signs of the star “wobbling” in its own spin as a result of planetary gravitational influences. Once identified, ESO called on other observatories around the world to carry out similar observations / comparisons to confirm their findings.
Although the planet lies within the “Goldilocks zone”, just how habitable is it likely to be is still open to question. Stars like Proxima Centauri, which is roughly one-seventh the diameter of our Sun, or just 1.5 times bigger than Jupiter, are volatile in nature, all activity within them entirely convective in nature, giving rise to massive stellar flares. As Proxima-B orbits so close to the star, it is entirely possible that over the aeons, such violent outbursts from Proxima Centauri have stripped away the planet’s atmosphere.
Proxima Cantauri compared with other stellar bodies – and Jupiter. Credit: Space.com
In addition, the preliminary data from ESO suggests the planet is either tidally locked to Proxima Centauri, or may have a 3:2 orbital resonance (i.e. three rotations for every two orbits) – either of which could make it an inhospitable place for life to gain a toe-hold. The first would leave one side in perpetual daylight and the other in perpetual night, while the second would limit any liquid water on the surface to the tropical zones.
Nevertheless, the discovery of another world in one part of our stellar backyard does raise the question of what NASA’s upcoming TESS mission might find when it starts searching the hundreds of nearby stars for evidence of exoplanets in 2018.
Juno’s Second Pass Over Jupiter
NASA’s Juno space craft made a second successful close sweep over the cloud-tops of Jupiter on Saturday, August 27th to complete its first full orbit around the planet. Speeding over the planet at a velocity of 208,000 km/h (130,000 mph) relative to Jupiter, Juno passed just 2,400 km (2,600 miles) above the cloud tops before heading back out into space, where it will again slowly decelerate under the influence of Jupiter’s immense gravity over the next 27 days, before it once again swing back towards the gas giant.
“Early post-flyby telemetry indicates that everything worked as planned and Juno is firing on all cylinders,” said Rick Nybakken, Juno project manager at NASA’s Jet Propulsion Laboratory, as telemetry on the flyby started being received on Earth some 48 mins after the flyby, which occurred at 13:44 UTC.
A twin view of Jupiter captured by Juno on August 23rd, when the spacecraft was some 4.4 million km (2.8 million miles) from the gas giant and approaching Jupiter to complete its first full orbit. On the left is a colour image from JunoCam, on the right an infra-red image. Credit: NASA/JPL / SwRI / MSSS
All of Juno’s science suite was in operation during the passage over Jupiter’s clouds. However, due to speed at which the gathered data can be returned to Earth, and given it cannot all be relayed in one go or necessarily continuously, it will be a week or more before everything has been transmitted back to Earth. Nevertheless the science team are already excited by the flyby.
“We are getting some intriguing early data returns as we speak,” Scott Bolton, principal investigator of Juno from the Southwest Research Institute, stated. Some of that data included initial images of Jupiter captured as Juno swept towards the planet during the run-up to periapsis. “We are in an orbit nobody has ever been in before, and these images give us a whole new perspective on this gas-giant world,” Bolton added.
July 14th: Jupiter with Io, Europa and Ganymede as seen by Juno after the craft had finished its critical engine burn to slip into a 53.5 day orbit around the giant planet. Juno will once again skim Jupiter’s cloud tops on Saturday, August 27th. Credit: NASA / JPL; SwRI / MSSS
NASA’s Juno mission to Jupiter is swinging back in towards the gas giant, on route to complete the first of some 37 planned polar orbits of the planet between now and February 2018 which are designed to probe the mysteries of the giant planet as never before.
As I reported in early July, the Juno space vehicle arrived at Jupiter on July 4th, where it completed a critical burn of its UK-built Leros-1b engine to ease its way into a highly elliptical orbit around Jupiter after a voyage of 2.8 billion km (1.74 billion miles) and 5 years, during which the craft first looped out past the orbit of Mars before falling back towards Earth to pick up a “gravity assist” to accelerate it on to its rendezvous with Jupiter.
The July 4th braking manoeuvre placed Juno in an orbit which, at its closest to Jupiter, skims just a few thousand kilometres above the planet’s cloud tops, and at its furthest sees Juno over 3 million kilometres from the planet. That first braking manoeuvre was undertaken with the probe’s science systems powered-down as a precautionary measure, and were powered-back up a few days after closest approach.
On August 27th, the vehicle will complete the first of these 53.5-day during “long” orbits, once again passing to within 4,200 km (2,600 mi) of Jupiter’s cloud tops at the equator, after arcing down over the planet’s north pole – and this time, all of the science instruments will remain operational, including JunoCam, the vehicle’s imaging system.
JunoCam has actually be in continuous operation in ” marble movie” mode since July 11th, 2016, capturing 5 full-colour images per hour, watching Jupiter spin from a distance (a sample of this movie is embedded blow – not Jupiter’s spin is greatly speeded-up). However, Jupiter is so small in most of the images – just 50 pixels across – that these haven’t been a source of interest to the media. As Juno approaches Jupiter on August 27th, however, the imaging system will switch from “marble movie” mode to gathering images at a higher rate to fully capture the close flyby as the craft passes over Jupiter’s north pole, curls around the planet north-to-south, before heading back out into space once more on the second of its “long” orbits.
JunoCam has a relative narrow field of view, so the images it captures on August 27th will be tightly focus on Jupiter’s clouds, and not as panoramic as those we’re been accustomed to seeing from the Hubble Space Telescope and from the now defunct Galileo mission. But they should still hopefully prove spectacular.
The next time Juno makes a close approach to Jupiter after this will be on October 19th. At that time, the science instruments will again be powered-off while the craft makes a second orbital burn, this time to reduce its orbit around Jupiter of 53.5 days to just 14 days, allowing the primary science mission to start.
This is intended to improve our understanding of Jupiter’s formation and evolution. The spacecraft will investigate the planet’s origins, interior structure, deep atmosphere and magnetosphere. Juno’s study of Jupiter will help us to understand the history of our own solar system and provide new insight into how planetary systems form and develop in our galaxy and beyond. It will also, for the first time, allow us to “see” below Jupiter’s dense clouds.
Selling the ISS?
This past week, NASA hosted a Journey to Mars showcase, looking at the space agency’s plans for developing the means to send humans to Mars in the 2030s. The actual plans for doing so are still pretty nebulous, but much of in revolves around the current development of the Orion Multi-Purpose Crew Vehicle (MPCV) and its supporting systems (including deep-space habitat modules), and the rocket system which will be used to launch it, the Space Launch System (SLS).
This being the case, the event was hosted at NASA’s Michoud Assembly Facility in New Orleans, where the core stage of the SLS vehicle the Orion MPCV. Included in the event was a trip to see a further test firing of one of the RD25 engines which will power the SLS at launch, and were previously used to power the space shuttle during its ascent to orbit.
However, what particularly grabbed the attention of the media was the announcement that the space agency is looking to sell the International Space Station to a private entity or entities in the mid-2020s, under the understanding that said entity/ies will keep the station active and continue to allow NASA to have access to it.
The move is a bold one. Currently, the ISS is the biggest single component of NASA’s budget, (just over US $3 billion in 2016 and projected to pass US $4 billion in 2020), and is only funded through until 2024. Thus, selling it to a private concern, could allow NASA to continue to make use of the station for research purposes beyond 2024 without having to meet all of the hefty costs involved in actually operating the station, potentially freeing-up some of the money dedicated for ISS support for use elsewhere.
Quite who would be willing to buy the ISS – both SpaceX and Boeing are apparently on NASA’s list of potential interested parties, although the interest may not be reciprocal – and quite how NASA’s international partners feel about the idea, is unclear.
Inara Pey: Living in a Modemworld 