Something’s wrong with Jupiter’s aurorae. Although they are observed at both poles, X-ray aurorae have only been consistently spotted in the north. Now, a new Nature Astronomy study has revealed that a persistent southern X-ray aurora has finally been observed – but weirdly, it acts independently of its northern counterpart.

Scientists have long been baffled by the mechanisms by which these glorious light shows are produced on Jupiter. This new paper, led by University College London (UCL) planetary scientists, brings up more questions than it answers.

“How does Jupiter produce bright, energetic, and dynamic auroras while its sibling, Saturn, does not?” William Dunn, an astrophysicist from UCL, said to IFLScience.

Dunn described the discovery of the southern aurora, via the XMM-Newton and Chandra X-ray satellites, as “confusing”, and although he and his team have several ideas as to how it comes about, they hope that the Juno mission will ultimately help solve the mystery.

Aurorae on Earth, whether you’re nearer to the Arctic or the Antarctic, are generally weaker than Jupiter’s, and they’re formed via a different mechanism.

When extremely energetic electrical fields accumulate along Earth’s magnetic field lines – triggered by anything from regular solar wind to a highly energetic solar flare – electrons are rapidly accelerated towards the ground. When they collide with molecules in the atmosphere, they become energetically “excited” – and when they calm down again, they release photons that appear to us as aurorae.

You can actually tell what molecules have been hit based on the color of the ephemeral, dancing dragons. Oxygen procures yellow-green hues, and nitrogen produces more red-violet shades, for example. Either way, they’re very much dependent on the incoming solar wind.

Jupiter is, in all respects, far more alien. Unlike ours – which we see in the visible part of the electromagnetic spectrum – both the northern and southern lights there are dominated by X-rays.

“To make these X-ray signatures the planet needs to accelerate oxygen ions to 5,000 kilometers (3,107 miles) per second… enough to completely strip oxygen of all its electrons,” Dunn explained.

Although they are out of sync with each other, their appearances can be described as powerful “pulses” that “happen like clockwork”. The southern X-ray outbursts, for example, seem to happen every 11 minutes, but it’s unclear as to why they’re so regular.

The electrical fields near Jupiter’s poles are around 30 times stronger than Earth’s. Weirdly though, the aurorae don’t seem to appear around them, which suggests they aren’t causing them.

It’s been proposed that ripples in the Jovian atmosphere are allowing electrons to accelerate enough to cause aurorae. This is generally thought to be a result of the planet’s own rotation, but it was also observed quite prominently back in 1991 when the catastrophic, multi-stage impact of Comet Shoemaker-Levy 9 sent shockwaves through the atmosphere.

Solar wind also has some influence, as does the volcanic debris jettisoned from nearby Io.

Nevertheless, these ideas do not adequately explain the precise timing of the X-ray pulses, nor do they elucidate why they’re so incredibly energetic. Dunn’s team have a few ideas of their own, with one imagining the planet to be akin to a giant musical instrument.

They suggest that when solar wind smashes into Jupiter’s magnetic field, it causes the field lines to vibrate like “the strings on a guitar”.

This vibration causes oxygen and sulfur ions to leap up and collide with Jupiter’s atmosphere at breakneck speeds, which would explain both the timing and the high-energy nature of both the northern and southern lights. Their independent behaviors, though, is still rather difficult to explain.

Only time will tell if they’re correct, but until then, Jupiter will remain the Solar System’s largest planetary enigma.

Read more: http://www.iflscience.com/space/jupiters-newly-detected-southern-aurora-doing-something-incredibly-strange/

With every generation of telescopes, we are getting a better idea of what the young universe looked like and the latest observation from the Atacama Large Millimeter/submillimeter Array (ALMA) has thrown quite a curve ball.

By studying two early universe Milky Way-like galaxies, astronomers have discovered the progenitors of giant spiral galaxies were embedded in huge super halos of hydrogen gas. The material in these halos is believed to be building blocks for the hundred billion of stars that will eventually form in these galaxies. These observations are reported in Science.

“ALMA has solved a decades-old question on galaxy formation,” co-author Chris Carilli, an astronomer with the National Radio Astronomy Observatory, said in a statement.”We now know that at least some very early galaxies have halos that are much more extended thanpreviously considered, which may represent the future material for galaxy growth.”

The international team of researchers observed the Milky Way-like galaxies from when the universe was just over a billion years old. The study of these was not an easy task. The galaxies were discovered using even more distant quasars, which are exceptionally bright galaxies. The light of the quasar can show the presence of a foreground galaxy but usually, we cant learn much more than that. Luckily ALMA seems to be able to overcome this.

“Imagine a tiny firefly next to a high-power searchlight. That’s what astronomers are up against when it comes to observing these youthful versions of our home galaxy,” added lead author Marcel Neeleman a postdoctoral fellow at the University of California, Santa Cruz.”We can now see the galaxies themselves, which gives us an amazing opportunity to learn about the earliest history of our own galaxy and others like it.”

ALMA looks at the infrared and microwave universe, which allows it to capture hard-to-see distant and dim objects, such as these galaxies.

Researchers are now planning to expand this search and are aiming to observe a large number of early galaxies over the next few years. The mysteries of these objects are living on borrowed time.

Read more: http://www.iflscience.com/space/early-universe-galaxies-like-ours-are-surrounded-by-super-halos/

This was a golden year for planetary exploration thanks to all of the NASA and European Space Agency missions that were planned and implemented decades ago. Not since Apollo and the epic space race of the Cold War has space featured so heavily in the public eye.

So here are the top ten space events that I got most excited about in 2015:

1. Pluto Flyby by New Horizons

For me the biggest scientific result of the year, if not the decade, was the revelation by New Horizons that the frozen distant world of Pluto was as active and varied as any we had yet explored.

Organic material staining the surface orange, kilometres high water-ice mountains plunging into freshly resurfaced nitrogen-ice sheets and a collapsing atmosphere all made this dwarf planet astoundingly exciting and well worth the almost decade long journey to reach.

While this world is definitely not a planet (having a system of moons almost as massive in total as it is) the distant frozen dwarf planet is truly King amongst the new class of Plutoids that represent a distinct phase of planet formation.

^{The sharpest views of Pluto that NASAs New Horizons spacecraft obtained during its flyby.}

2. Water (but no atmosphere) on Mars

The announcement that Mars has flowing water on its barren surface was of huge importance as (at least on Earth), where theres flowing water, theres life. It meant we need to reassess the conditions under which water can exist and hence the possibilities for life.

The red planet made the list because of the incredible discovery by NASAs MAVEN spacecraft that the Sun was responsible for stripping the Martian atmosphere away, turning a water-rich world nearly four billion years ago into the inhospitable desert it is today.

The atmosphere isnt locked away in rocks underneath the surface, a la Total Recall, but instead has been lost to space meaning future colonists may well have to bring more of their supplies than thought.

3. Philae called home (and more Rosetta discoveries)

The idea that theres a spacecraft sitting on a comet still astounds me.

That #WakeUpPhile came true (briefly) in 2015 is a great reason to feature Rosetta again this year and explore the scientific discoveries from the comet, such as how the iconic tail forms from comet ice as well as the discovery of organic material. These compounds are the precursors to several different amino acids as found in organisms on Earth, meaning objects like Comet 67P could have brought the ingredients for life to the planets earliest days.

One of the big surprises is that the water in this comet has three times more heavy water (where hydrogen is replaced with its heavier isotope deuterium) than in the oceans of Earth. Wherever the water came from that made life possible on Earth it wasnt from comets like this.

4. Alien worlds discovered by Kepler

NASAs Kepler spacecraft continued to search for exoplanets around stars in our Milky Way, even after the failure of critical gyroscope stabilisers, bringing the total to 1,030 confirmed worlds (with thousands more candidates to be followed up).

One of the most exciting discoveries was of a rocky world similar in size to Earth orbiting a Sun-like star, Earths cousin. Although this is far from saying its Earth-like. We dont know if Kepler-452b is habitable yet as we cant measure its atmosphere.

However, a rocky world orbiting in the goldilocks zone suitable for liquid water to exist was a huge step forward in our ultimate search for Earth 2.0 and finding life beyond Earth.

5. Breakthrough Listen to hunt for ET

An incredible US$100 million initiative funded by Russian billionaire Yuri Milner to use two of the worlds largest radio telescopes including Australias Parkes (aka The Dish) to search the closet million stars and 100 nearest galaxies for alien signals. Breakthrough Listen will also use the optical Lick observatory in the chance that aliens have upgraded from radio/TV signals to laser-based communications.

In the decade-long search astronomers will upgrade the telescopes to the benefit of astronomy worldwide, and learn incredible things about the stars of our Milky Way. Most excitingly of all we may be able to answer one of the most important questions of all time: are we alone?

6. The Martian

Rarely does a film convey the science so well that it could be considered an educational resource, but The Martian managed it.

One of the most observed events of the celestial year, the lunar eclipse was also, in some circles, reported as being the harbinger of the apocalypse.

This was because during a lunar eclipse the moon turns blood red as sunlight travelling through our atmosphere scatters onto the moon. Only longer, red, wavelengths of light make it through the atmosphere which is why the sun low on the horizon appears red. The result is that the blood is being illuminated by all the sunrises and sunsets of Earth.

This eclipse occurred when the moon was at its closest point to Earth (known as a perigee or super moon), making this a beautiful sight for most, and a terrifying one for some. If you missed it this year we wont see a similar super lunar eclipse until 2033.

8. Dawn exploration of Ceres

NASAs Dawn mission to Ceres, a dwarf planet and largest body in the asteroid belt, was overshadowed by the flashier, high speed flyby of Pluto by the New Horizons mission.

Yet as Dawn drifted towards Ceres on the faintest of thrust from its ion engine it spotted a huge surprise. Ceres had bizarre bright regions shining out from an asphalt-dark world. These were so unexpected that NASA even created an online poll so everyone could make a guess.

9. Launch of LISA Pathfinder

The race to test Einsteins final prediction of gravitational waves heated up this year, and 2016 will only be more exciting.

The European Space Agency successfully launched LISA Pathfinder in December meaning that, technically, it wont begin its mission (orbiting between the Earth and Sun) until February. It still makes the list as this is a critical first step and technology demonstrator of the ultimate space-based gravitational wave detector, LISA, or as it is now called, the New Gravitational wave Observatory.

The spacecraft formerly known as LISA will consist of three satellites in space precisely measuring their respective distances with lasers. These can then measure the change in their separation as a ripple in spacetime itself, caused by the titanic collisions of distant blackholes, passes by. An audacious goal which is why checking the technology is even possible first with LISA Pathfinder is a smart move.

10. Growing space lettuce

Aboard the International Space Station astronauts took their first bite of space-grown lettuce.

Alan Duffy, Research Fellow, Swinburne University of Technology

Read more: http://www.iflscience.com/space/space-2015-was-out-world

Last year, astronomers noticed something very odd about a star called KIC 8462852 it was experiencing huge, unexplainable dips in brightness.

The theory that caught the public imagination, that aliens were building a giant megastructure around it, is almost certainly wrong, but the mystery continues to deepen. The latest development is that the overall brightness of the star has been steadily decreasing over the last few years, alongside these much larger dips in brightness. And none of the proposed theories can seemingly explain it.

Scientists usedthe Kepler Space Telescope to observe that the starbecame3 percent fainter over fouryears. Even though it is very unlikely to be aliens, the explanation for KIC 8462852’s behavior, when we find it, will probably shake up an area of astronomy we just don’t know which one.

During the time Kepler first observed KIC 8462852, it experienced a series of dips in brightness in a manner never seen in any star of its age and type. Several explanations were proposed, all of them unlikely; most famously, there was the explanation that aliens were building a vast construction around the star, occasionally obscuring our view. KIC 8462852, also known as Tabby’s star, after Dr Tabetha Boyajian, the original paper’s first author, was promptly dubbed the alien megastructure star.

Subsequent research ruled this idea out. However, what was initially the leading alternative, a swarm of interfering comets, has a few problems too, leaving everyone bewildered. This year, some astronomers claimed to have found that KIC 8462852has been dimming for a century, but in May a rival team argued this was an effect of using different telescopes, rather than real changes in the star.

Now, however, apre-print of a yet-to-be peer-reviewed paper has been placed on arXiv, claiming Tabby’s Star becamefainter throughout the time Kepler was observing it. Unlike the original “dips”, which sawKIC 8462852 fade briefly before returning to its previous brightness, the new claims are for long-term fading as well, which so far has not been reversed.

Authors Ben Montet, a graduate student at CalTech, and the Carnegie Institute’s Dr Joshua Simon conducted an analysis of the raw pixel data from Kepler’s 53 images of KIC 8462852 taken between 2009 and 2013. In addition to the week-long dip in brightness that first brought the mysterious star to wider attention, and the nine shorter dips, they report a slower but ongoing dimming.

Over the first1,000 days, KIC 8462852 faded approximately linearly at a rate of 0.341 0.041 percent per year,for a total decline of 0.9 percent. KIC 8462852 then dimmed much more rapidly in the next 200 days, with its flux [total light emitted] dropping by more than 2 percent, the authors report.

The final 200 days of Kepler’s observations may have involved a further small decrease in brightness, but the uncertainty in measurements is too large to be sure. A fall of around 3 percent is completely unprecedented for a star so similar to the Sun, though.

Kepler was designed to detect and characterize events with timescales of minutes to hours, the authors note, explaining why these long-term trends were not detected previously.

Montet and Simon analyzed 548 comparable stars in case the changes were an artifact of some unknown change to Kepler’s sensitivity. Although 0.6 percent showed a decline in brightness similar to that seen during the first 1,000 days, none came close to the subsequent, much more rapid, drop.

The part that really surprised me was just how rapid and non-linear it was, Montet said toGizmodo. We spent a long time trying to convince ourselves this wasnt real. We just werent able to.

So, for now, the mystery ofKIC 8462852 continues to deepen.

^{KIC 8462852’s brightness with time.Kepler rotates every three months for protection against the Sun. Observations arecolor-coded by Kepler’s orientationto ensure this was not affecting the dimming.Montet and Simon}

Read more: http://www.iflscience.com/space/not-aliens-but-megastructure-star-keeps-getting-stranger/

Scientists have discovered hidden “nanoflares” on the Sun, small explosions that we think may explain one of our star’s biggest mysteries.

Known as the solar corona mystery, the answer has long eluded scientists. The corona, which is the upper part of the solar atmosphere, is millions of degrees hotter than the surface, known as the photosphere. This is confusing – shouldn’t the greatest heat be nearest the source?

A few years ago, scientists proposed nanoflares as a possible solution. Million to billions of times weaker than solar flares, they had largely escaped detection. But after their subtle brightening was spotted on the Sun, it was suggested they may supply the missing energy needed to heat the corona. The only problem was we weren’t seeing enough of them to fully explain it.

Now a team led by Shin-nosuke Ishikawa from the Japan Aerospace Exploration Agency (JAXA) has an answer. Publishing their findings in Nature Astronomy, the researchers discovered hidden nanoflares that are only visible via their X-ray emissions, which may provide the missing energy.

“We found a signature of small flares without any brightening intensity increase [in visible light],” Ishikawa told IFLScience. “It’s the first time we’ve ever seen them without brightening.

To make the finding, the team used a NASA sounding rocket – which is one that flies briefly into suborbit before returning to Earth. Called FOXSI-2 (Focusing Optics X-ray Solar Imager) and launched in 2014, it used a highly sensitive X-ray detector to spot X-ray emissions on the Sun, which were likely coming from nanoflares.

It was one of two sounding rockets launched by the team over the last few years, the other being FOXSI-1, launched in 2012. The scientists now plan to launch another in summer 2018, called (you guessed it) FOXSI-3, to get more data on nanoflares.

“X-ray imaging is especially difficult,” Ishikawa said, commenting on why this discovery hasn’t been made before. “The Sun is too bright [for other instruments like NASA’s NuSTAR telescope], but our sounding rocket experiment is optimised for the Sun.”

The main issue at the moment is we don’t know how many nanoflares the Sun is producing. If it’s a lot, it’s probable that they are responsible for heating the solar corona. This latest study, however, was only able to see the overall X-ray emissions from nanoflares. It could not spot them individually.

That may all change in the future. Ishikawa and his colleagues have two proposals in the works for advanced satellites that would hunt for nanoflares. One, called FOXSI, is a NASA proposal that would launch in 2021. The other, Phoenix, is a proposal to JAXA with a launch in 2025.

Read more: http://www.iflscience.com/space/were-a-step-closer-to-solving-one-of-the-suns-biggest-mysteries/

Astronomers using ESO’s Very Large Telescope (VLT) have captured an incredible image of a Jupiter-size planet forming around dwarf star PDS 70. This detection is the telescope’s first planetary formation discovery.

The achievement is reported in two papers published in Astronomy & Astrophysics (here and here). The planet, PDS 70b, weighs a few times the mass of Jupiter and orbits its star at a distance of 3 billion kilometers (1.8 billion miles), slightly further than Uranus is from the Sun. It is also quite hot with a temperature of at least 1,000 degrees Celsius (roughly 1,800 degrees Fahrenheit), definitely hotter than any planet in the Solar System.

The discovery was possible thanks to the new VLT instrument SPHERE (Spectro-Polarimetric High-contrast Exoplanet REsearch instrument), one of the best planet-hunting instruments ever built. The team was able to block the light from the bright star and focus on the disk of material surrounding it. The gap in the material has been known to astronomers for a long time, and now they have finally spotted the planet they suspected existed there.

“These discs around young stars are the birthplaces of planets, but so far only a handful of observations have detected hints of baby planets in them,” lead author Miriam Keppler, from the Max Planck Institute for Astronomy, said in a statement. “The problem is that until now, most of these planet candidates could just have been features in the disc.”

The planet is presumed to be in a very early phase of planetary formation. It is estimated to be 5.4 million years old. And that’s not all. After several years of observations, the researchers have learned a lot about the object. The planet’s orbit is roughly circular around the star and it orbits in the same plane as the disk.

“Keppler’s results give us a new window onto the complex and poorly-understood early stages of planetary evolution,” added André Müller, leader of the second team to investigate the young planet. “We needed to observe a planet in a young star’s disc to really understand the processes behind planet formation.”

The observation allowed the researchers to determine the general properties of the planet and its atmosphere. Catching a planet so early in its life, and learning so much about it, gives us very important insights to test against our theoretical models of planet formation.

Read more: http://www.iflscience.com/space/check-out-this-spectacular-image-of-a-brandnew-baby-planet/