Look up! Your guide to some of the best meteor showers for 2018



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The 2017 Geminids as seen from Ecuador, against the backdrop of the splendid Milky Way (centre) and the Large Magellanic Cloud (right).
Flickr/David Meyer, CC BY-NC-ND

Jonti Horner, University of Southern Queensland and Tanya Hill, Museums Victoria

This year gets off to a relatively slow start when it comes to seeing the annual major meteor showers.

The Quadrantids, one of the big three annual showers, are lost to the vagaries of the full Moon in early January.

But the year’s other two most active annual showers – the Perseids (in August) and Geminids (in December) – are set to put on fine displays.

So when and where should you look to have the best chance of seeing nature’s fireworks?

Here we present the likely meteoric highlights of 2018. These are the meteor showers most likely to put on a good show this year.


Read more: Stars that vary in brightness shine in the oral traditions of Aboriginal Australians


For each shower, we give the forecast activity period and the predicted time of maximum. We also provide charts showing you where to look, and give the peak rates that could be seen under perfect conditions (known as the maximum Zenithal Hourly Rate, or ZHR).

The actual rate you see will always be lower than this value – but the higher a shower’s radiant in the sky and the darker the conditions, the closer the observed rate will get to this ideal value.

To see the best rates it is well worth trying to find a good dark site, far from street lights. Once outside, make sure to give your eyes plenty of time to adapt to the darkness (at least half an hour).

Showers that can only be seen from one hemisphere are denoted by either [N] or [S], with those that can be seen globally marked as [N/S].

Lyrids [N/S; N favoured]

Active: April 14-30

Maximum: April 22, 6pm UT = April 23, 2am AWST (WA) = 4am AEST (QLD/NSW/ACT/Vic/Tas)

ZHR: 18+

Parent: Comet C/1861 G1 (Thatcher)

The Lyrids hold the record for the shower with the longest recorded history, having been observed since at least 687BC.

That longevity is linked to the orbit of the Lyrid’s parent comet, discovered in 1861 by A. E. Thatcher. Comet Thatcher moves on a highly inclined, eccentric orbit, swinging through the inner Solar system every 415 years or so. Its most recent approach to Earth was in 1861.

Compared with many other comets, Thatcher’s orbit is relatively stable, as the only planet with which it can experience close encounters is Earth. This means the meteors it sheds continue to follow roughly the same orbit.

Over the millennia, that shed debris has spread all around the comet’s vast orbit, meaning that for thousands of years, every time Earth intersects Comet Thatcher’s orbit, the Lyrids have been seen, as regular as clockwork.

One study of the orbits of Lyrid meteors even suggests the shower may have been active for at least a million years.

Across Australia, the Lyrids are best seen an hour before sunrise, when the radiant is at its highest [Brisbane 5am].
Museums Victoria/stellarium

These days, the Lyrids are usually a moderately active shower, producing somewhere between 10 and 20 fast, bright meteors per hour at their peak. Occasionally, though, the Lyrids have thrown up a surprise, with rates climbing far higher for a period of several hours.

The best of those outbursts seem to occur every 60 years or so, with the most recent occurring in 1982 when observed rates reached or exceeded 90 per hour.

No such outburst is predicted for 2018, but even in quiet years, the Lyrids are still a fun shower to observe.

From the USA, the radiant is well placed from late evening until early morning [Chicago 11pm].
Museums Victoria/stellarium

They are best seen from northern latitudes, but their radiant is far enough south for observers throughout Australia to observe them in the hours before dawn.

For observers at mid-northern latitudes, the Lyrid radiant reaches suitable altitude by about 11pm local time. Viewers in the southern hemisphere have to wait until the early hours of the morning before reasonable rates can be observed.

The forecast time of maximum this year favours observers in Australia and east Asia but the timing of maximum has been known to vary somewhat, so observers around the globe will likely be keeping their eyes peeled, just in case!

Perseids [N]

Active: July 17 – August 24

Maximum: August 12, 8pm UT – August 13, 8am UT = from August 12, 9pm BST (UK) = 10pm CEST (Europe) = 6pm EDT (East Coast, US) = 3pm PDT (West Coast, US) for 12 hours

ZHR: 110

Parent: Comet 109P/Swift-Tuttle

For observers in the northern hemisphere, the Perseids are a spectacular summer highlight. At their peak, rates often reach or exceed 100 meteors per hour, and they are famed for their frequent spectacular fireballs.

The Perseids are probably the best known and most widely observed of all modern meteor showers. They are remarkably consistent, with peak rates usually visible for a couple of evenings, and fall in the middle of the northern hemisphere summer holiday season. The warm nights and frequent clear skies at that time of year make the shower a real favourite!

Like the Lyrids, the Perseids have a long and storied history, having been observed for at least 2,000 years. Their parent comet, 109P/Swift-Tuttle, is a behemoth, with the largest nucleus of the known periodic comets – some 26km in diameter.

It has likely moved on its current orbit for tens of thousands of years, all the time laying down the debris that gives us our annual Perseid extravaganza. It will next swing past Earth in 2126 when it will be a spectacular naked eye object.

From the UK, the Perseids radiant is visible all night and summer is the perfect time for meteor watching [Greenwich 9pm].
Museums Victoria/stellarium

This year the forecast maximum for the Perseids favours observers in Europe, although given the length of peak activity, any location in the northern hemisphere has the potential to see a spectacular show on the night of August 12.

But don’t despair if it’s cloudy that night, as the Perseids have a relatively broad period of peak activity, meaning that good rates can be seen for a few days either side of their peak.

In 2018, the peak of the Perseid shower coincides with the New Moon, and so is totally unaffected by moonlight, which makes this an ideal year to observe the shower.

The further north you are, the earlier the shower’s radiant will be visible. But reasonable rates can typically be seen any time after about 10pm, local time. The later in the night you observe, the better the rates will be, as the radiant climbs higher into the sky.

It is not uncommon for enthusiastic observers to watch the shower until dawn on the night of maximum, seeing several hundred meteors in a single night.

A fantastic Perseids display from 2016 over Austria.
Flickr/Michael Karrer, CC BY-NC

Draconids [N]

Active: October 6-10

Maximum: October 9, 12:10am UT = 1:10am BST (UK) = 2:10am CEST (Europe)

ZHR: 10+

Parent: Comet 21P/Giacobini-Zinner

The Draconids are a fascinating meteor shower, although in most years, somewhat underwhelming. Unlike the previous showers, the Draconids are a relatively young meteor shower that can vary dramatically from one year to the next.

First observed less than a century ago, the Draconids (also known as the Giaocobinids) are tied to a Jupiter-family comet called 21P/Giacobini-Zinner.

That comet was the first to be visited by a spacecraft, and has frequent close encounters with Jupiter, which continually nudges its orbit around. These encounters also perturb the meteor stream the comet is laying down, sometimes enhancing rates at Earth and sometimes diminishing them.

In the early 20th century, it was realised that Comet Giacobini-Zinner’s orbit comes close enough to Earth that we might be able to see meteors as we plough through the debris it leaves behind.

This led to the first predictions of Draconid activity. Sure enough, in 1920, the great meteor observer W. F. Denning confirmed the existence of the shower, with a mere five meteors observed between October 6 and October 9.

In 1933 and 1946, the Draconids produced two of the greatest meteor displays of the 20th century – great storms, with peak rates of several thousand meteors per hour. In those years, Earth crossed the comet’s orbit just a month or two after the comet passed through perihelion (closest approach to the Sun), and Earth ploughed through dense material in the comet’s wake.

After 1946, the Draconids went quiet, all but vanishing from our skies. Jupiter had swung the comet onto a less favourable orbit. Only a few Draconids were seen in 1972, then again in 1985 and 1998.

The late 1990s saw a renaissance in our ability to predict and understand meteor showers, born of enhanced activity exhibited by the Leonid meteor shower. Using the techniques developed to study the Leonids, astronomers predicted enhanced activity from the Draconids in 2011, and the predicted outburst duly occurred, with rates of around 300 meteors per hour being observed.

Europe is well placed to catch some Draconids streaming from the eye of the dragon, near the star Rastaban [Paris 12:30am].
Museums Victoria/stellarium

This year comet Giacobini-Zinner once again passes through perihelion and swings close to Earth’s orbit. The chances are good that the shower will be active – albeit unlikely to produce a spectacular storm.

Modelling suggests that rates of 20 to 50 faint meteors per hour might be seen around 12:14am UT on October 9. Other models suggest that rates will peak about 45 minutes earlier, with lower rates of 15 to 20.

The Draconid radiant is circumpolar (that is, it never sets) for locations north of 44°N, and is highest in the sky before midnight. This year, the Moon is new at the time of the forecast peak, which is ideally timed for observers in Europe.

If skies are clear that evening, it is well worth heading out at around 11:30pm BST on October 8 (12:30am CEST on October 9) and spending a couple of hours staring north, just in case the Draconids put on another spectacular show.

Taurids [N/S]

Active: September 10 – December 10

Maxima: October 10 (Southern Taurids); November 12 (Northern Taurids)

ZHR: 5 + 5

Parent: Comet 2P/Encke

Of all the year’s meteor showers, the one that dumps the greatest amount of dust into Earth’s atmosphere are the Taurids. The inner Solar system contains a vast swathe of debris known as the Taurid stream. It is so spread out that Earth spends a quarter of the year passing through it.

In June, that debris spawns the Daytime Taurid meteor shower, which (as the name suggests) occurs during daylight hours, and is only really known thanks to radio observations.

After leaving the stream for a little while, Earth penetrates it again at the start of September, and activity continues right through until December. Hourly rates fluctuate up and down, with several distinct peaks and troughs through October and November.

The Taurid stream is complex – with at least two main components, known as the northern and southern branches. Typically, the Southern Taurids are active a little earlier in the year and reach their peak about a month before the northern branch.

During northern autumn, the Taurids can be seen radiating from the western sky before dawn [Paris 6:30am October 10].
Museums Victoria/stellarium
For the southern spring, the Taurids radiate from the northern sky before dawn [Melbourne 3:30am November 12].
Museums Victoria/stellarium

The Taurids are slow meteors and feature plenty of bright fireballs. So even though their rates are low, they are well worth looking out for, particularly when other showers are also active, such as the Draconids, the Orionids and the Leonids.

Put together, these showers make the northern autumn or the southern spring a great time to get out and look for natural fireworks.

Orionids [N/S]

Active: October 2 – November 7

Maximum: October 21

ZHR: 20+

Parent: Comet 1P/Halley

Twice a year, Earth runs through the stream of debris littered around the orbit of Comet 1P/Halley. Throughout the month of October this gives rise to the Orionid meteor shower.

The Orionids are a fairly reliable meteor shower with a long, broad maximum. Typically, peak rates can last for almost a week, centred on the nominal maximum date. Throughout that week, Orionid rates can fluctuate markedly, leading to a number of distinct maxima and minima.

Orionid meteors are fast – much faster than the Taurids that are active at the same of year. Like the Taurids, they are often bright, the result of the high speed at which the meteoroids hit Earth’s atmosphere.

Before sunrise, Orion stands upright in the southwest as seen from the northern hemisphere [Chicago 5am].
Museums Victoria/stellarium
But from the southern hemisphere Orion appears to be standing on his head, in the northern sky before dawn [Sydney 5am].
Museums Victoria/stellarium

The Orionid radiant rises in the late evening and is only really high enough in the sky for reasonable rates to be seen after midnight. As a result, the best rates are usually observed in the hours before dawn.

This works well this year, as the Moon will be in its waxing gibbous phase, setting some time after midnight and leaving the sky dark, allowing us to watch for pieces of the most famous comet of them all.

Geminids [N/S]

Active: December 4-17

Maximum: December 14, 12:30pm UT = Australia: December 14, 8pm AWST (WA) = 10:30pm (QLD) = 11:30pm AEST (NSW/ACT/Vic/Tas) = United States: December 14, 7:30am (EST) = 5:30am (PST) = 2:30am (Hawaii)

ZHR: 120

Parent: Asteroid 3200 Phaethon

As the year comes to a close, we reach the most reliable and spectacular of the annual meteor showers – the Geminids. Unlike the Perseids and the Lyrids, which have graced our skies for thousands of years, the Geminids are a relatively new phenomenon.

They were first observed just 150 years ago, and through the first part of the 20th century were a relatively minor shower. But since then rates have improved decade-on-decade, to the point where they are now the best of the annual showers, bar none.

The reason for their rapid evolution is that their orbit (and that of their parent body, the asteroid Phaethon) is shifting rapidly over time, precessing around the Sun (wobbling like a slow spinning top). As it does so, the centre of Phaethon’s orbit, and the centre of the Geminid stream, are moving ever closer to Earth.

For northern locations, the radiant rises shortly after sunset, and good rates can be seen from mid-evening onwards. For observers in the southern hemisphere, the radiant rises later, so good rates are delayed until later at night (as detailed in our 2015 report on the shower).

Although the time of maximum this year seems to favour observers in the Americas and Australia, peak rates from the Geminids usually last around 24 hours, and so good rates should be visible around the globe.

This year the maximum falls a day before the Moon reaches first quarter so the best rates are visible (after midnight, local time) when the Moon will have set and moonlight will not interfere.

Australia’s summer meteor shower, the consistent and spectacular Geminids in the early morning sky [Brisbane 4am].
Museums Victoria/stellarium
The Geminids appear high overhead over American skies in winter [Los Angeles midnight].
Museums Victoria/stellarium

Given that rates from the Geminids continue to climb, the estimated ZHR of 120 is likely to be somewhat conservative. Rates in excess of 130, and even as high as 200 per hour, have been seen in recent years.

Geminids are medium-speed meteors and are often bright. The individual meteors also seem to last just that bit longer than other showers, a fact likely related to their parent object’s rocky nature.

The ConversationWherever you are on the planet, the Geminids are a fantastic way to bring the year to an end, and we will hopefully be treated to a magnificent display this year.

Jonti Horner, Vice Chancellor’s Senior Research Fellow, University of Southern Queensland and Tanya Hill, Honorary Fellow of the University of Melbourne and Senior Curator (Astronomy), Museums Victoria

This article was originally published on The Conversation. Read the original article.

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Google’s artificial intelligence finds two new exoplanets missed by human eyes


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Artist impression of Kepler-90i, the eighth planet discovered orbiting around Kepler-90.
NASA

Jake Clark, University of Southern Queensland

Two new exoplanets have been discovered thanks to NASA’s collaboration with Google’s artificial intelligence (AI). One of those in today’s announcement is an eighth planet – Kepler-90i – found orbiting the Sun-like star Kepler-90. This makes it the first system discovered with an equal number of planets to our own Solar system.

A mere road trip away, at 2,545 light-years from Earth, Kepler-90i orbits its host star every 14.4 Earth days, with a sizzling surface temperature similar to Venus of 426°C.

The new exoplanets are added to the growing list of known worlds found orbiting other stars.

The Kepler-90 planets have a similar configuration to our solar system with small planets found orbiting close to their star, and the larger planets found farther away.
NASA/Ames Research Center/Wendy Stenzel

This new Solar system rival provides evidence that a similar process occurred within Kepler-90 that formed our very own planetary neighbourhood: small terrestrial worlds close to the host star, and larger gassy planets further away. But to say the system is a twin of our own Solar system is a stretch.


Read more: Exoplanet discovery by an amateur astronomer shows the power of citizen science


The entire Kepler-90 system of eight planets would easily fit within Earth’s orbit of the Sun. All eight planets, bar Kepler-90h, would be too hostile for life, lying outside the so-called habitable zone.

Evidence also suggests that planets within the Kepler-90 system started out farther apart, much like our own Solar system. Some form of migration occurred, dragging this system inwards, producing the orbits we see in Kepler-90 today.

Kepler-90 is a Sun-like star, but all of its eight planets are scrunched into the equivalent distance of Earth to the Sun.
NASA/Ames Research Center/Wendy Stenzel

Google’s collaboration with NASA’s space telescope Kepler mission has now opened up new and exciting opportunities into AI helping with scientific discoveries.

So how exactly did Google’s AI discover these planets? And what sort of future discoveries can this technology provide?

Training AI for exoplanet discoveries

Traditionally, software developers program computers to perform a particular task, from playing your favourite cat video, to determining exoplanetary signals from space based telescopes such as NASA’s Kepler Mission.

These programs are executed to serve a single purpose. Using code intended for cat videos to hunt exoplanets in light curves would lead to some very interesting, yet false, results.

Googles’s AI is programmed rather differently, using machine learning. In machine learning, AI is trained through artificial neural networks – somewhat replicating our brain’s biological neural networks – to perform tasks like reading this article. It then learns from its mistakes, becoming more efficient at its particular task.

Google’s DeepMind AI, AlphaGo, was trained previously to play Go, an extremely complex yet elegant Chinese board game. Last year, AlphaGo defeated Lee Sedol, the world’s best Go player, by four games to one. It simply trained itself by watching thousands of previously played games, then competing against itself.

In our exoplantary case, AI was trained to identify transiting exoplanets, sifting through 15,000 signals from the Kepler exoplanet catalogue. It learned what was and wasn’t a signal caused by an exoplanet eclipsing its host star. These 15,000 signals were previously vetted by NASA scientists prior to the AI’s training, guiding it to a 96% efficiency of detecting known exoplanets.

Researchers then directed their AI network to search in multiplanetary systems for weaker signals. This research culminated in today’s announcement of both Kepler-90i and another Earth-sized exoplanet, Kepler-80g, in a separate planetary system.

Hunting for more exoplanets using AI

Google’s AI has analysed only 10% of the 150,000 stars NASA’s Kepler Mission has been eyeing off across the Milky Way galaxy.

How AI helps in the hunt for other exoplanets.

There’s potential then for sifting through Kepler’s entire catalogue and finding other exoplanetary worlds that have either been skimmed by scientist or haven’t been checked yet, due to Kepler’s rich data set. And that’s exactly what Google’s researchers are planning to do.

Machine learning neural networks have been assisting astronomers for a few years now. But the potential for AI to assist in exoplanetary discoveries will only increase within the next decade.

Beyond Kepler

The Kepler mission has been running since 2009, with observations slowly coming to an end. Within the next 12 months, all of its on-board fuel will be fully depleted, ending what has been, one of the greatest scientific endeavours in modern times.

NASA’s new TESS mission will inundate astronomers with 20,000 exoplanetary candidates in the next two years.
Chet Beals/MIT Lincoln Lab

Kepler’s successor, the Transiting Exoplanet Survey Satellite (TESS) will be launching this coming March.


Read more: A machine astronomer could help us find the unknowns in the universe


TESS is predicted to find 20,000 exoplanet candidates during its two-year mission. To put that into perspective, in the past 25 years, we’ve managed to discover just over 3,500.

This unprecedented inundation of exoplanetary data needs to either be confirmed by other transiting observations or other methods such as ground-based radial velocity measurements.

The ConversationThere just isn’t enough people-power to sift through all of this data. That’s why these machine learning networks are needed, so they can aid astronomers in sifting through big data sets, ultimately assisting in more exoplanetary discoveries. Which begs the question, who exactly gets credit for such a discovery?

Jake Clark, PhD Student, University of Southern Queensland

This article was originally published on The Conversation. Read the original article.

We’ve found an exo-planet with an extraordinarily eccentric orbit



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An artist’s impression of the exoplanet in close orbit to a star.
ESA, NASA, G. Tinetti (University College London, UK & ESA) and M. Kornmesser (ESA/Hubble)

Jonti Horner, University of Southern Queensland; Jake Clark, University of Southern Queensland; Rob Wittenmyer, University of Southern Queensland, and Stephen Kane, University of California, Riverside

The discovery of a planet with a highly elliptical orbit around an ancient star could help us understand more about how planetary systems form and evolve over time.

The new planet, HD76920b, is four times the mass of Jupiter, and can be found some 587 light years away in the southern constellation Volans, the Flying Fish. At its closest it skims the surface of its host star, HD76920. At its furthest, it orbits almost twice as far from its star as Earth does from the Sun.

Superimposing HD76920b’s orbit on the Solar system shows how peculiar it is. Its orbit is more like that of the asteroid Phaethon than any of the Solar system’s planets.
Jake Clark

Details of the planet and its discovery are published today. So how does this fit into the planet formation narrative, and are planets like it common in the cosmos?


Read more: A fleeting visit: an asteroid from another planetary system just shot past Earth


The Solar system

Before the first exoplanet discovery, our understanding of how planetary systems formed came from the only example we had at the time: our Solar system.

Close to the Sun orbit four rocky planets – Mercury, Venus, Earth and Mars. Further out are four giants – Jupiter, Saturn, Uranus and Neptune.

Scattered in their midst we have debris – comets, asteroids and the dwarf planets.

The eight planets move in almost circular orbits, close to the same plane. The bulk of the debris also lies close to that plane, although on orbits that are somewhat more eccentric and inclined.

How did this system form? The idea was that it coalesced from a disk of material surrounding the embyronic Sun. The colder outer reaches were rich in ices, while the hotter inner regions contained just dust and gas.

The Solar system formed from a protoplanetary disk, surrounding the young Sun.
NASA/JPL-Caltech

Over millions of years, the tiny particles of dust and ice collided with one another, slowly building ever larger objects. In the icy depths of space, the giant planets grew rapidly. In the hot, rocky interior, growth was slower.

Eventually, the Sun blew away the gas and dust leaving a (relatively) orderly system – roughly co-planar planets, moving on near-circular orbits.

The exoplanet era

The first exoplanets, discovered in the 1990s, shattered this simple model of planet formation. We quickly learned that they are far more diverse than we could have possibly imagined.

Some systems feature giant planets, larger than Jupiter, orbiting incredibly close to their star. Others host eccentric, solitary worlds, with no companions to call their own.

Artist’s impression of the Hot Jupiter HD209458b – a planet so close to its star that its atmosphere is evaporating to space.
European Space Agency, A.Vidal-Madjar (Institut d’Astrophysique de Paris, CNRS, France) and NASA

This wealth of data reveals one thing – planet formation and evolution is more complicated and diverse than we ever imagined.

Core accretion vs dynamical instability

As a result of these discoveries, astronomers developed two competing models for planet formation.

The first is core accretion, where planets form gradually, through collisions between grains of dust and ice. The theory has grown out of our old models of Solar system formation.

The competing theory is dynamical instability. Once again, the story begins with a disk of material around a youthful star. But that disk is more massive, and becomes unstable under its own self-gravity, causing clumps to grow. These clumps rapidly form planets, in thousands of years.

Massive protoplanetary disks can become unstable, rapidly giving birth to giant planets.

Both models can explain some, but not all, of the newly discovered planets. Depending on the initial conditions around the star, it seems that both processes can occur.

Each theory offers potential to explain eccentric worlds in somewhat different ways.

How do you get an eccentric planet?

In the dynamical instability model you can easily get several clumps forming and interacting, slinging one another around until their orbits are both tilted and eccentric.

Under the core accretion model things are a bit harder, as this method naturally creates co-planar, ordered planetary systems. But over time those systems can become unstable.

One possible outcome is for one planet to eject the others through a series of chaotic encounters. That would naturally leave it as a solitary body, following a highly elongated orbit.

Chaotic planetary systems can eject planets entirely, leading to lonely rouge planets.
NASA/JPL-Caltech

But there is another option. Many stars in our galaxy are binary – they have stellar companions. The interactions between a planet and its host star’s sibling could readily stir it up and eventually eject it, or place it on an extreme orbit.

An eccentric planet

This brings us to our newly discovered world, HD76920b. A handful of similarly eccentric worlds have been found before, but HD76920b is unique. It orbits an ancient star, more than two billion years older than the Sun.

The orbit HD76920b is following is not tenable in the long-term. As it swings close to its host star, it will experience dramatic tides.

A gaseous planet, HD76920b will change shape as it swings past its star, stretched by its enormous gravity. Those tides will be far greater than any we experience on Earth.

That tidal interaction will act over time to circularise the planet’s orbit. The point of closest approach to the star will remain unchanged, but the most distant point will gradually be dragged closer in, driving the orbit towards circularity.

All of this suggests that HD76920b cannot have occupied its current orbit since its birth. If that were the case, the orbit would have circularised aeons ago.

Extremely eccentric planets have been discovered before, but this is the first around such an ancient star.
Goddard Space Flight Center/NASA

Perhaps what we’re seeing is evidence of a planetary system gone rogue. A system that once contained several planets on circular (or near circular) orbits.


Read more: Exoplanet discovery by an amateur astronomer shows the power of citizen science


Over time, those planets nudged one another around, eventually hitting a chaotic architecture as their star evolved. The result – chaos – with most planets scattered and flung to the depths of space leaving just one – HD76920b.

The truth is, we just don’t know – yet. As is always the case in astronomy, more observations are needed to truly understand the life story of this peculiar planet.

The ConversationOne thing we do know is the story is coming to a fiery end. In the next few million years, the star will swell, devouring its final planet. Then, HD76920b will be no more.

Jonti Horner, Vice Chancellor’s Senior Research Fellow, University of Southern Queensland; Jake Clark, PhD Student, University of Southern Queensland; Rob Wittenmyer, Associate Professor (Astrophysics), University of Southern Queensland, and Stephen Kane, Associate Professor, University of California, Riverside

This article was originally published on The Conversation. Read the original article.

How do we turn a drain into valued green space? First, ask the residents


Leila Mahmoudi Farahani, RMIT University and Cecily Maller, RMIT University

This article is based on a paper being presented at the State of Australian Cities Conference in Adelaide, November 28-30.


The green infrastructure of our cities includes both publicly owned, designed and delineated areas and less formal, unplanned areas of vegetation — informal green spaces. These spaces account for a large proportion of urban green areas. However, they are often among the most overlooked and neglected urban spaces, which contributes to negative perceptions, a recent study has found.

Yet informal green spaces represent a largely untapped opportunity to improve liveability and residents’ health and social well-being. Especially in lower socioeconomic areas that lack formal green spaces, improving the condition of informal green spaces can promote their use and enhance neighbourhood liveability.


Further reading: Our cities need more green spaces for rest and play — here’s how


We can’t afford to waste green space

Green spaces are important indicators of quality of life in cities and suburbs. They are shown to have a wide range of positive impacts.

For residents, the benefits include physical, mental and social health and wellbeing. The multiple environmental benefits include ecosystem services, improving microclimate and reducing air pollution, alongside biodiversity conservation.

Owing to such benefits, governments invest a lot in greening projects or improving green spaces. Sometimes these interventions include informal green spaces to increase their accessibility, use and potential benefits to residents.

The researchers surveyed residents about the Upper Stony Creek channel area.
Author provided

Upper Stony Creek, an urban waterway restoration in Melbourne’s west, is a good example. Work will soon transform the concrete drainage channel, now separated from the residential area, into an accessible urban wetland and park.


Further reading: How Melbourne’s west was greened


Residents’ perceptions and uses

Clean Air and Urban Landscapes (CAUL) Hub researchers from RMIT University investigated residents’ perceptions and uses of Upper Stony Creek and the adjacent informal green space before the start of the intervention.

Interviews with residents showed overall impressions of the site were negative. An overwhelming majority of them commented on the site’s undesirable features.

Lack of regular maintenance, lack of access, feeling unsafe and litter were among their main concerns. Safety concerns included natural hazards, such as the presence of snakes (encouraged by a lack of regular maintenance), crime and local drug trade. These concerns affected when and how often residents used the site.

The negative perceptions suggested residents were looking forward to the intervention. They believed it would improve the informal green space and their neighbourhood.

Residents do use the informal green space alongside the concrete channel.

In spite of their misgivings, residents found value in using the area for practices typically found in formal green spaces such as dog-walking. They also used it for less typical practices such as motorbike riding. The lack of restrictions in these spaces allows for uses that might not be acceptable in more formalised urban spaces.

In fact, residents appreciated the sense of exploration, informality and feelings of being away from urbanisation that the site provided.

Informal green spaces are filling a niche not met by more formal green spaces. This means interventions to transform informal green spaces should, where possible, take into account residents’ current uses of these areas.


Further reading: More than just drains: recreating living streams through the suburbs


Ensuring work improves these spaces

Our findings highlight the importance of considering and understanding residents’ perceptions and concerns about informal green spaces for informing work on these spaces.

Our case study suggests small interventions, which aim to resolve the main concerns such as lack of maintenance and safe access, can increase the use of informal green spaces without resorting to entirely formalising the space. In fact, understanding residents’ needs and expectations could result in more cost-effective interventions that won’t jeopardise the informal character of such areas.

Each informal green space will be unique in its features and characteristics, as will residents’ perceptions of it. Therefore, understanding these sites and residents’ lived experiences and concerns more completely through in-depth consultation will be important to ensure interventions meet community needs and expectations.

A sound knowledge of how informal green spaces are used, or of why they are not being used, can inform planners and decision-makers when intervening in such spaces to increase the liveability of urban neighbourhoods.


The ConversationThe authors welcome collaboration with local councils and other organisations to help understand residents’ uses and perceptions of informal green spaces when undertaking improvements or waterway restorations.

Leila Mahmoudi Farahani, Research Officer in Urban Studies, RMIT University and Cecily Maller, Vice Chancellor’s Senior Research Fellow, Centre for Urban Research, RMIT University

This article was originally published on The Conversation. Read the original article.

Preventing Murray-Darling water theft: a space agency can help Australia manage federal resources


Andrew Dempster, UNSW

This is the first article in the series Australia’s place in space, where we’ll explore the strengths and weaknesses, along with the past, present and the future of Australia’s space presence and activities.


An independent report into allegations of water theft and corruption in the Murray-Darling Basin has recommended fundamental reforms to the system.

Solutions suggested in the report focus on the state of New South Wales, and involve metered pumps and public access to information. Others have proposed a space-based solution: wide application of “random audits” of water meters by an independent monitoring system: satellites.

But what if we went further. Forget the random audits – why not use satellites to monitor everywhere in the Murray-Darling Basin, all the time?

It’s another argument supporting Australia’s need of a space agency.


Read more: Is the Murray Darling Basin plan broken?


Australian solutions to Australian problems

Among the many arguments in favour of Australia having its own space agency, the use of satellites to collect local data to solve local problems is a vital one.

Under the Australian Space Research Program (the ASRP, which ended in 2013), my colleagues and I developed a design for a pair of Synthetic Aperture Radar satellites that would map soil moisture for all of Australia, every 3 days, to a resolution of 10 metres. We called it “Garada”. This system could readily detect overuse of water of the type noted in the Murray Ddarling Basin, as it was occurring.

Our report was delivered to the Space Policy Unit (which later became the Space Coordination Office), and then the idea stopped dead. There was no mechanism within the public sphere to advance the project: it fell into the hole where a space agency should have been.

The Garada satellites are big and expensive, not exactly the low-cost, “Space 2.0”-focused solutions where most of Australia’s opportunities lie (such as small satellites and startup companies).

However, when we did the study, we showed how the satellite system could be viable if it was considered to be infrastructure. We showed that despite a hefty price tag of A$800 million, the satellite would pay for itself if:

  • its data led to an increase of 0.35% in GDP for non irrigated agriculture, or
  • its data led to a decrease of 7% of irrigation infrastructure, or
  • it was able to save 1% of Murray-Darling water flows.

Read more: Ten reasons why Australia urgently needs a space agency


In a practical sense, the space agency, which needn’t have a big budget itself, wouldn’t have to pay for such a satellite; it just needs a seat at the infrastructure table and compare benefit-to-cost ratios with other projects such as roads and railways. In my opinion, one part of the agency’s role, should it exist, is to make sure infrastructure such as this is considered.

Another important thing to acknowledge here is that both the problem and solution here are federal, with multiple states as stakeholders. An agency that functions to solve problems of this type is not consistent with the sort of “go it alone” approach recently put forward by the ACT and South Australia.

Satellites forge ahead

Even without a space agency, recent years have started to see satellites used to solve Australia-specific problems. The NBN “Skymuster” satellites deliver broadband to remote areas where fibre and wireless solutions were impractical. But they were 100% imported – not an Australian solution.

Start-up Fleet in Adelaide has recently received first-round funding to deliver internet of things services to remote areas from a constellation of cubesats. This may have been achieved against the odds without a local ecosystem, but the company’s official stance is “Australia can no longer afford not to have a space agency”. A number of other start-ups are also starting to gain traction.

Australian universities have been successful in launching and operating cubesats in the QB50 constellation, such as our own UNSW-EC0. These are the first Australian-built satellites to be launched in 15 years. My own group has also delivered GPS receivers as payloads on Defence missions Biarri and Buccaneer.

Australia not at the space table

The world’s largest space conference, the International Astronautical Congress is to be held in Adelaide, September 25-29 2017.

When members of the global space community – NASA, the European Space Agency, the Chinese National Space Agency, the UK Space Agency, and others – meet at the congress to make decisions on missions, strategy, collaborations and other global directions in space, Australia will not be at the table, because we do not have a space agency.


Read more: The 50-year old Outer Space Treaty needs adaptation


The more general commercial and scientific implications related to this have been well outlined. What I have tried to highlight here is simply one example of a possible great many: there are local, practical implications linked to failed advancement of an infrastructure project that relies on expertise in space.

Submissions to the Federal Government’s Review of Australia’s Space Industry Capability closed in August, with many in the industry hoping that its report in March 2018 will recommend an Australian space agency.

The ConversationThe benefits can be broader than most Australians realise – we need to imagine better.

Andrew Dempster, Director, Australian Centre for Space Engineering Research; Professor, School of Electrical Engineering and Telecommunications, UNSW

This article was originally published on The Conversation. Read the original article.

Mission over: the final countdown to Cassini’s fatal plunge into Saturn



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An illustration of Cassini as it plunges into Saturn’s atmosphere.
NASA/JPL-Caltech

Ed Kruzins, CSIRO and Richard Stephenson, CSIRO

When the Cassini space probe makes its final descent into Saturn later today, data from the final nine hours of the mission will be sent back to NASA’s tracking station in Canberra, Australia.

As the probe descends, it will capture images and data from Saturn and its atmosphere, revealing more of the planet’s secrets. Under the spacecraft’s normal operations, its instruments first store and later forward images and data to Earth.

But in Cassini’s final hours, it will be transmitting home in real time, with the signals picked up by the CSIRO-managed Canberra Deep Space Communication Complex (CDSCC).


Read more: The secrets of Titan: Cassini searched for the building blocks of life on Saturn’s largest moon


The CDSCC is part of NASA’s Deep Space Network, one of three tracking stations around the world that provide vital two-way radio contact with Cassini and 30 other spacecraft including Voyagers 1 and 2.

Cassni’s final journey in local AEST times.
NASA/JPL-Caltech/CSIRO

Cassini’s final bonanza of data, transmitted as weak radio signals, will take 83 minutes to travel 1.5 billion km at the speed of light to reach the giant dish antennas in Canberra.

At an estimated 9:54pm AEST tonight (September 15), CSIRO’s team at CDSCC will capture the final signals as Cassini, travelling at more than 111,000km per hour, plunges into Saturn’s atmosphere.

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How to destroy the probe

NASA decided to safely dispose of Cassini into Saturn, ending its mission as a shooting star. With the spacecraft nearly out of fuel and possible loss of control, this plan will prevent accidental collisions with any of Saturn’s moons and potential biological contamination by microbial stowaways from Earth.

Viewed from Saturn, the last moments of Cassini would look similar to a meteor entering Earth’s atmosphere.

An illustration of Cassini breaking apart after entering Saturn’s atmosphere.
NASA/JPL-Caltech

From Earth, the world will await the bittersweet moment when NASA’s Jet Propulsion Laboratory mission control announces loss of signal. Cassini’s final call home will have been made.

It will mark the end of a 20-year mission, a joint venture between NASA, the European Space Agency and the Italian Space Agency.

Mission objectives

Inspired by the earlier flypast by the twin Voyager spacecraft, the two-part mission was actually known as the Cassini-Huygens mission.

The main craft was designed to study Saturn and its environs, while the piggybacking Huygens probe was to land on Titan, the planet’s largest moon.

Throughout its odyssey, every step of Cassini’s journey has been followed by the dishes at CDSCC in Canberra. It was the first tracking station to make contact with Cassini after its launch from Cape Canaveral in October 1997.

The Cassini spacecraft and Huygens probe begin their seven-year journey to Saturn after a successful launch on October 15, 1997.
NASA

It then tracked Cassini throughout its seven-year journey to Saturn, handling the vital communications as it arrived and was placed into orbit around the planet in July 2004.

As the first spacecraft to orbit Saturn, it has studied the planet, its rings and its 62 moons, seven of which were discovered by Cassini.

In 2005 the Huygens probe transmitted data as it landed safely on the surface of Titan. This was the first landing on a world in the outer Solar System.

The Huygens probe’s descent to Titan.

Saturn’s wonders revealed

Cassini has now witnessed almost half a Saturn year, which is 29 Earth years long.

While Voyagers 1 and 2 had spectacular encounters with the outer planets interspersed by years of travel, Cassini has delivered science on a daily basis.

Like a Swiss Army Knife of spacecraft, Cassini has a plethora of scientific instruments on board.

Eight of Cassini’s science instruments are planned to be turned on during the final plunge, including the Ion and neutral Mass Spectrometer (INMS).
NASA/JPL-Caltech

While the most inspiring data is the images, for staff at CDSCC the excitement has centred around performing dozens of unique radio science experiments with the Cassini team.

Using a process called bistatic radar, which is the deep space version of sonar, the data received made it possible to measure the size and distribution of particles in Saturn’s rings.

Saturn reigns supreme, encircled by its retinue of rings. You can also see Saturn’s famous north polar vortex and hexagon.
NASA/JPL-Caltech/Space Science Institute

It was also used to map the terrain and depths of ethane and methane lakes on the surface of Titan. For Cassini’s final bistatic observations of Titan earlier this year, key members of Cassini’s science team travelled to Canberra to witness the data coming into CDSCC first-hand.

Staff found it exhilarating to watch the pure excitement on the faces of Cassini’s team standing in their Canberra control room as the spacecraft’s faint signals were being received.

Bistatic scattering reveals the details on Titan.

To some of us, the data may have appeared as not much more than a slightly higher peak in a hash of radio noise, but to the mission team it meant discovering a shoreline or a lake bottom on the surface of a world more than a billion kilometres away. Being a part of these discoveries was a proud moment for CDSCC and its CSIRO team.

The rest of the probes

As we say goodbye to Cassini, CDSCC continues to track more than 30 other spacecraft, not only NASA probes but also those of other international space agencies in Europe, Japan and India.

The Canberra antennas still support both Voyager spacecraft for several hours each day, receiving data from the edge of the Solar System and beyond.

Canberra Deep Space Communication Complex will keep track of other spacecraft after Cassini’s final plunge into Saturn.
CSIRO CDSCC

NASA’s Juno has only just begun its primary mission, transmitting scientific data as it orbits Jupiter. Its highly elliptical orbit brings the spacecraft dangerously close to Jupiter (5,000km) before retreating away from the radiation-intense planet.

New Horizons, which flew past Pluto in 2015, has set a course for an encounter with a Kuiper Belt object on January 1, 2019. The spacecraft is periodically woken from hibernation to check system functions before being returned to slumber.

The next few years will see a quantum shift as the Deep Space Network moves to supporting proposed human missions to the Moon, asteroids and Mars.

Some key numbers for Cassini’s Grand Finale and final plunge into Saturn.
NASA/JPL-Caltech

For now though, CDSCC is concentrating on Cassini’s final moments, delivering its last breath of data to NASA scientists who will continue to study the information for decades to come.


Read more: A look back at Cassini’s incredible mission to Saturn before its final plunge into the planet


Using the big 70-metre antenna dish at CDSCC as the prime receiver, it will be backed up by a smaller 34m dish. To add even further redundancy into the system, the European Space Agency has a 35m dish in New Norcia, Western Australia, which will also listen to Cassini’s radio whispers.

Cassini’s final hours will be a bittersweet moment for the CDSCC team, losing a spacecraft that for 20 years had become a daily part of our lives.

We will say a fond farewell to an incredible mission, safe in the knowledge that we’ve been a part of an adventure that revealed Saturn as a real place, full of wonders, for future generations to explore.


There are a several ways to watch Cassini’s final hours, including:

You can also follow Cassini on Twitter @CassiniSaturn and Facebook at NASACassini.

The Conversation

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Ed Kruzins, Facilities Program Director Nasa Operations Canberra Deep Space Communication Complex , CSIRO and Richard Stephenson, Deep Space Network Operations Supervisor, CSIRO

This article was originally published on The Conversation. Read the original article.

The secrets of Titan: Cassini searched for the building blocks of life on Saturn’s largest moon


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Cassini captures Saturn’s largest moon, Titan.
NASA/JPL-Caltech/SSI

Courtney Ennis, La Trobe University

Lakes and seas of liquid methane, rain from hydrocarbon clouds, and evidence of poisonous hydrogen cyanide in the atmosphere of Titan were just some of the discoveries the Cassini probe made of Saturns’s largest moon.

The space probe has now made its final pass of Titan as it heads towards its grand finale plunge into the ringed planet later this week.

Dubbed Cassini’s “goodbye kiss” by NASA, Titan has been the subject of much scrutiny by the probe, with 127 flybys on its 13-year mission exploring the planetary system.


Read more: A look back at Cassini’s incredible mission to Saturn before its final plunge into the planet


One of Cassini’s greatest feats is its contribution to untangling the complicated chemistry of Titan, no doubt one of the more chemically diverse objects in our Solar System.

One last look at Titan on Cassni’s final journey.
NASA/JPL-Caltech

We have known for some time that the combination of ultraviolet rays from the Sun and particle bombardment has altered the mainly nitrogen and methane atmosphere over time.

This chemistry has sustained a thick, orange smog layer surrounding the entire body, shrouding Titan’s oceans and landscape from view prior to Cassini’s arrival.

The murky orange disk of Saturn’s moon Titan.
NASA/JPL/Space Science Institute

Probing Titan

With Cassini’s toolkit of advanced sensing instruments – combined with atmospheric sampling by the Huygens probe during its 2005 descent to the surface – the mission has developed a comprehensive picture of Titan’s chemistry.

Touchdown on Titan with the Huygens probe.

Intriguingly, on top of the hundreds of molecules accounted for, chemical models developed here on Earth incorporating Cassini data predict the existence of even more complex material.

Of potential significance to biochemistry, these molecules have evaded observation over the relatively short Cassini mission, being either out of view or present at levels below the detection limits of the equipment.

Even if only formed in small quantities in the atmosphere it is plausible that these life-bearing species have built up on the surface over Titan’s history.
So what are these chemicals and how do they come to be?

This composite image shows an infrared view of Saturn’s moon Titan from Cassini’s flyby in November 2015. The near-infrared wavelengths in this image allow Cassini’s vision to penetrate the haze and reveal the moon’s surface.
NASA/JPL/University of Arizona/University of Idaho

Cyanide snow

Unlike Earth, oxygen atoms are rather scarce in Titan’s atmosphere. Water is locked as surface ice and there appear to be no abundant sources of O₂ gas.

In oxygen’s place, we see nitrogen play a more significant role in Titan’s atmospheric chemistry.

Here, common products of nitrogen reactions are the cyanide family of compounds, of which hydrogen cyanide (HCN) is the simplest and most abundant.

As the numbers of cyanide molecules build up at lower, colder altitudes they form cloud layers of large floppy polymers (tholins) and budding ice aerosols.

As the aerosols descend to the surface, shells of methane and ethane ice form further layers on the exterior. This acts to protect the inner organic material on its descent to the surface before being dispersed in hydrocarbon lakes and seas.

Cassini’s view of Titan’s high northern latitudes in May 2012, the lakes on the left are full of liquid hydrocarbons while those on the top right are only partially filled, or represent saturated ground or mudflat.
NASA/JPL-Caltech/ASI/Cornell

Surprisingly it is these cyanide compounds, chemicals closely associated with toxicity and death to Earthly lifeforms, that may actually provide avenues for life-bearing biomolecules to form in space environments.

Some simulations predict that cyanides trapped in ices and exposed to space radiation can lead to the synthesis of amino acids and DNA nucleobase structures – the building blocks of life on Earth.

Excited by these predictions and their implications toward astrobiology, chemists have rushed to explore these reactions in the laboratory.

Synchrotron experiments: Titan-in-a-can

Our contributions to astrochemistry have focused on simulating the atmosphere of Titan and its cyanide haze.

With a specialised gas cell installed at the Australian Synchrotron, we are able to replicate the cold temperatures associated with Titan’s cloud layers.

Cassini’s spectrum view of the southern polar vortex shows a signature of frozen hydrogen cyanide molecules (HCN).
NASA/JPL-Caltech/ASI/University of Arizona/SSI/Leiden Observatory and SRON

By injecting cyanides (the friendlier variety) into our cell we can determine the size, structure and density of Titan aerosols as they grow over time; probing with infrared light from the facility.

These results have provided us with a list of signatures for which we can locate cyanide aerosols using infrared astronomy.

The next step will be to seed these aerosols with organic species to determine if they can be identified in extraterrestrial atmospheres.

Perhaps these signals will act as a beacon for future explorations designed to search for complex organic material in more remote space locations – potentially even on the “giant Earth” exoplanets in distant star systems.

Life off Earth

Space provides us a unique perspective to turn back the pages of chemistry.
Among the planets, moons and stars – and the not quite emptiness between – we can study the initial reactions thought to have started chemistry here on Earth.

Using ever more sensitive telescopes and advanced spacecraft, we have uncovered chemical nurseries – pockets of gas and ice exerted to harsh space radiation – in our Solar System and beyond.

Such cold, icy objects as Titan, the moons of Jupiter, Trans-Neptunian Objects (such as Pluto and other minor bodies in the Kuiper belt and beyond), as well as microscopic interstellar dust particles, all generate higher-order organic molecules from simple chemical ingredients.


Read more: Cloudy with a chance of life: how to find alien life on distant exoplanets


As far as we know, the lack of heat and liquid water precludes life to exist at these worlds.

However, we can look for clues regarding life’s origins on a primitive Earth. Were life-bearing chemicals delivered via comet impact, or made in-house near the early ocean shores or deep sea volcanoes? Observing the chemistry of distant objects could one day provide the answers.

The ConversationThese forays into our chemical history have been enabled by the significant steps we have taken in our exploration of space including, as a glowing example, the resounding success of Cassini’s exploration of Titan.

Courtney Ennis, Research Fellow, La Trobe University

This article was originally published on The Conversation. Read the original article.