Astronomers have discovered an exoplanet with a gigantic ring system, 200 times larger than that around Saturn.
An international team of astronomers has produced a new analysis of exoplanet data, showing how a ring system eclipses a star about 420 light years from Earth. Known as J1407, the star's age is estimated to be 16 million years, making it very young in stellar terms, with a mass 90% that of our Sun's. The accompanying planet is very large, at between 10 and 40 Jupiter masses, so it may in fact be a brown dwarf.
The planet's ring system – the first of its kind to be found outside our Solar System – is of gigantic size, much larger and heavier than Saturn's and described as "Saturn on steroids" by one astronomer. It is divided into at least 30 sections with a total diameter of 120 million km (75 million miles), equivalent to 80% of the distance between Earth and our Sun. Furthermore, gaps in the rings indicate that large satellites (“exomoons”) are present and may be up to 0.8 Earth masses.
“The details that we see in the light curve are incredible,” says Professor Matthew Kenworthy from the Leiden Observatory in the Netherlands, who led the study. “The eclipse lasted for several weeks, but you see rapid changes on time scales of tens of minutes as a result of fine structures in the rings. The star is much too far away to observe the rings directly, but we could make a detailed model based on the rapid brightness variations in the star light passing through the ring system. If we could replace Saturn’s rings with the rings around J1407b, they would be easily visible at night and be many times larger than the full moon.”
Credit: Matthew Kenworthy, Leiden Observatory
“This planet is much larger than Jupiter or Saturn, and its ring system is roughly 200 times larger than Saturn’s rings are today,” said Eric Mamajek, professor of physics and astronomy at the University of Rochester, who co-authored the paper. “You could think of it as kind of a super Saturn.”
“We see the rings blocking as much as 95 percent of the light of this young Sun-like star for days,” he adds. “So there is a lot of material there that could then form satellites.”
In their data, the astronomers found at least one clean gap within the ring structure: “One obvious explanation is that a satellite formed and carved out this gap,” says Kenworthy. “The mass of the satellite could be between that of Earth and Mars. The satellite would have an orbital period of approximately two years around J1407b.”
The researchers believe that the rings will become thinner in the next several million years and eventually disappear altogether as satellites coalesce from the material in the disks. They are encouraging amateur astronomers to help monitor this remarkable star system, to help detect the next eclipse of the rings and narrow down the possible range of values for the planet's orbital characteristics and mass.
“The planetary science community has theorised for decades that planets like Jupiter and Saturn would have had, at an early stage, disks around them that then led to the formation of satellites,” Mamajek explains. “However, until we discovered this object in 2012, no-one had seen such a ring system. This is the first snapshot of satellite formation on million-kilometre scales around a substellar object.”
NASA has released an animated view of the dwarf planet Ceres, taken by the approaching Dawn spacecraft.
As NASA's Dawn spacecraft closes in on Ceres, new images show the dwarf planet at 27 pixels across, about three times better than the calibration images taken in early December. These are the first in a series of images that will be taken for navigation purposes during the probe's approach.
Over the next several weeks, Dawn will deliver increasingly better and better images of the dwarf planet – leading up to the spacecraft's capture into orbit around Ceres on 6th March. These images will continue to improve as the spacecraft spirals closer to the surface during its 16-month study.
"We know so much about the solar system and yet so little about dwarf planet Ceres. Now, Dawn is ready to change that," said Marc Rayman, the chief engineer and mission director, based at NASA's Jet Propulsion Laboratory in California.
The best images of Ceres so far were taken by the Hubble Space Telescope in 2003-4. These most recent images from Dawn, taken 13th January 2015 – at 80% of Hubble resolution – are not quite as sharp. But Dawn's images will surpass Hubble's at the next imaging opportunity, at the end of January.
"Already, the [latest] images hint at first surface structures such as craters," said Andreas Nathues, lead investigator for the framing camera team at the Max Planck Institute for Solar System Research, Germany.
Dawn's arrival will mark the first time a spacecraft has ever been to a dwarf planet. By far the largest body in the main asteroid belt, Ceres comprises approximately one-third of the mass of the whole belt, which lies between Mars and Jupiter. With an average diameter of 590 miles (950 km), it is the sixth largest body in the inner Solar System by mass and volume. Scientists believe it contains a vast amount of ice – a potentially major resource for human colonists in the future. Thanks to its small escape velocity and rich resources, Ceres could serve as a main base and transport hub for asteroid mining infrastructure while providing abundant water, fuel, and oxygen for ships passing through to more distant objects like the moons of Jupiter.
"The team is very excited to examine the surface of Ceres in never-before-seen detail," said Chris Russell, principal investigator for the mission, based at the University of California, Los Angeles. "We look forward to the surprises this mysterious world may bring."
Astronomers have observed and measured a neutron star slipping out of view because of the warp in space-time its orbit creates. The star is expected to reappear in about 160 years.
Illustration of one orbit of pulsar J1906 (on the right, with radio beams) around its companion (centred). In the space-time curvature caused by the companion (blue), the pulsar rotation axis slants throughout the orbit. For illustration the effect is exaggerated 1 million times here.
Videos and image credit: Joeri van Leeuwen / ASTRON / University of British Columbia (CC BY-SA 4.0)
In an interstellar race against time, astronomers have measured the space-time warp in the gravity of a binary star system and determined the mass of a neutron star – just before it vanished from view.
The team, including University of British Columbia astronomer Ingrid Stairs, measured the masses of both stars in a binary pulsar system called J1906, which lies in a globular cluster known as Terzan 5, about 25,000 light years away. The pulsar spins and emits a lighthouse-like beam of radio waves every 144 milliseconds and orbits its companion star in under four hours.
"By precisely tracking the motion of the pulsar, we were able to measure the gravitational interaction between the two highly compact stars with extreme precision," says Stairs, a professor of physics and astronomy. "These two stars each weigh more than the Sun, but are still over 100 times closer together than the Earth is to the Sun. The resulting extreme gravity causes many remarkable effects."
According to general relativity, neutron stars wobble like a spinning top as they move through the gravitational well of a massive, nearby companion star. Orbit after orbit, the pulsar travels through a space-time that is curved, which impacts the star's spin axis.
"Through the effects of the immense mutual gravitational pull, the spin axis of the pulsar has now wobbled so much that the beams no longer hit Earth," explains Joeri van Leeuwen, an astrophysicist at the Netherlands Institute for Radio Astronomy, and University of Amsterdam, who led the study.
"The pulsar is now all but invisible to even the largest telescopes on Earth. This is the first time such a young pulsar has disappeared through precession. Fortunately this cosmic spinning top is expected to wobble back into view, but it might take as long as 160 years."
Only a handful of double neutron stars have had their mass calculated, with J1906 being the youngest. The results were published on Thursday in the Astrophysical Journal and presented at the American Astronomical Society meeting.
NASA has announced the 1000th confirmed exoplanet discovered by the Kepler Space Telescope. Three of the newly confirmed exoplanets were found to orbit within habitable zones of their parent stars.
Launched by NASA in 2009, the Kepler space telescope became the first
instrument capable of finding Earth-sized and smaller extrasolar planets. Originally the mission was expected to last until 2016, but the second of four reaction wheels (used for aligning the telescope) failed in May 2013 – disabling the spacecraft and putting its future in doubt.
However, an alternative plan named K2 "Second Light" was presented for consideration in November 2013. This would involve Kepler operating in a reduced capability mode, but able to continue exoplanet discovery, using an ingenious "virtual" reaction wheel. K2 began in May 2014 and had scanned 35,000 stars by the end of the year. Its first confirmed exoplanet was detected in December 2014, a hot super-Earth 180 light-years away in the constellation Pisces.
Combining Kepler's original tally with hundreds of results from K2, a total of 4,175 potential candidates have now been observed, the 1,000th of which was officially verified this week, after a further eight new planets were added to the "confirmed" list. Three of the newly-validated worlds are located in their suns' habitable zone – the range of distances from the host star where liquid water might exist on the surface of an orbiting planet. Of the three, two are likely to be made of rock, like Earth.
Kepler-438b and Kepler-442b, pictured here in the top row, are less than 1.5 times the diameter of Earth. Kepler-438b lies around 475 light-years away and is 12% bigger than Earth, while Kepler-442b is 1,100 light-years away and 33% bigger than Earth. Both have relatively short orbits of 35 days and 112 days – similar to that of Mercury (88 days) in our own Solar System. However, their parent stars are smaller and cooler than Sol, making their habitable zones closer. The third, Kepler 440b, is less likely to be a rocky planet. On the bottom row are small habitable zone planets confirmed in previous years including Kepler-186f, Kepler-62e and Kepler-62f.
“Each result from the planet-hunting Kepler mission's treasure trove of data takes us another step closer to answering the question of whether we are alone in the Universe,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “The Kepler team and its science community continue to produce impressive results with the data from this venerable explorer.”
“With each new discovery of these small, possibly rocky worlds, our confidence strengthens in the determination of the true frequency of planets like Earth,” said co-author Doug Caldwell, SETI Institute Kepler scientist at NASA's Ames Research Centre in California. “The day is on the horizon when we’ll know how common temperate, rocky planets like Earth are.”
“Kepler collected data for four years – long enough that we can now tease out the Earth-size candidates in one Earth-year orbits,” said Fergal Mullally, another SETI Institute Kepler scientist. “We’re closer than we’ve ever been to finding Earth twins around other sun-like stars. These are the planets we’re looking for.”
Many of these exoplanets will be targeted in follow-up studies by the James Webb Space Telescope to characterise the atmospheres of distant worlds and search for signatures of life. Kepler has now discovered 1,000 exoplanets, but the James Webb and other future telescopes are expected to find even more.
If the current rate of discovery continues, then the number of confirmed exoplanets is predicted to surpass 13 million by the 2050s. This could reach into the hundreds of billions by the end of the century. In other words, pretty much every world in the Milky Way will have been catalogued. Assuming our telescopes also increase in magnification, we should also be able to observe them in close-up detail. We will then have to look at neighbouring galaxies for new planets.
NASA reports detecting an unusual increase, then decrease, in the amounts of methane in the atmosphere of the planet Mars, as well as Martian organic chemicals in powder drilled from a rock by the Curiosity rover.
This image illustrates possible ways methane might be added to Mars' atmosphere (sources) and removed from the atmosphere (sinks). The Curiosity rover has detected fluctuations in methane concentration in the atmosphere, implying both types of activity occur on modern Mars. Credit: NASA/JPL-Caltech/SAM-GSFC/Univ. of Michigan
NASA's Mars Curiosity rover has measured a tenfold spike in methane, an organic chemical, in the atmosphere around it and detected other organic molecules in a rock-powder sample collected by the robotic laboratory’s drill.
"This temporary increase in methane – sharply up and then back down – tells us there must be some relatively localised source," said Sushil Atreya of the University of Michigan, Ann Arbor, and Curiosity rover science team. "There are many possible sources, biological or non-biological, such as interaction of water and rock."
Researchers used Curiosity’s onboard Sample Analysis at Mars (SAM) laboratory a dozen times in a 20-month period to sniff methane in the atmosphere. During two of those months, four measurements averaged seven parts per billion. Before and after that, readings averaged only one-tenth that level.
Curiosity also detected different Martian organic chemicals in powder drilled from a rock dubbed Cumberland, the first definitive detection of organics in surface materials of Mars. These Martian organics could either have formed on Mars or been delivered to Mars by meteorites.
Organic molecules, which contain carbon and usually hydrogen, are chemical building blocks of life, although they can exist without the presence of life. Curiosity's findings from analysing samples of atmosphere and rock powder do not confirm whether Mars has ever harboured living microbes, but the findings do shed light on a chemically active modern Mars and on favourable conditions for life in the ancient past.
"We will keep working on the puzzles these findings present," said John Grotzinger, project scientist at the California Institute of Technology. "Can we learn more about the active chemistry causing such fluctuations in the amount of methane in the atmosphere? Can we choose rock targets where identifiable organics have been preserved?"
The researchers worked for many months to determine whether any of the organic material detected in the Cumberland sample was truly Martian. Curiosity’s SAM lab detected in several samples some organic carbon compounds that were, in fact, transported from Earth inside the rover. However, extensive testing and analysis yielded confidence in the detection of Martian organics.
The SAM analysed hydrogen isotopes from water molecules that had been locked inside a rock sample for billions of years and were freed when SAM heated it, yielding information about the past history of Martian water. The ratio of a heavier hydrogen isotope – deuterium – to the most common hydrogen isotope can provide a signature for comparison across different stages of a planet's history.
"It's really interesting that our measurements from Curiosity of gases extracted from ancient rocks can tell us about loss of water from Mars," said Paul Mahaffy, SAM principal investigator and lead author of a report published this week by the journal Science.
Click to enlarge
Cross-bedding seen in the layers of this Martian rock is evidence of water movement recorded by the waves or ripples of loose sediment the water passed over, such as a current in a lake. This image was acquired by the Mastcam on NASA's Curiosity Mars rover last month.
The ratio of deuterium to hydrogen has changed because the lighter hydrogen escapes from the upper atmosphere of Mars much more readily than heavier deuterium. In order to go back in time and see how the deuterium-to-hydrogen ratio in Martian water changed over time, researchers can look at the ratio in water in the current atmosphere and water trapped in rocks at different times in the planet’s history.
Martian meteorites found on Earth also provide some information, but this record has gaps. No known Martian meteorites are even close to the same age as the rock studied on Mars, which formed about 3.9 billion to 4.6 billion years ago, according to Curiosity’s measurements.
The ratio that Curiosity found in the Cumberland sample is about one-half the ratio in water vapour in today's Martian atmosphere, suggesting much of the planet's water loss occurred since that rock formed. However, the measured ratio is about three times higher than the ratio in the original water supply of Mars. This suggests much of Mars' original water was lost before the rock formed.
Curiosity is one element of NASA's ongoing research and preparation for human exploration of Mars in the 2030s. Other upcoming missions include the InSight drilling probe in 2016, another Curiosity-style rover in 2020 and a sample return mission in 2023.
Using new data from Kepler, an astrobiologist has attempted to update the famous Drake equation. It is estimated that a biotic planet may be expected within 10-100 light years from Earth, while the nearest intelligent life is probably a few thousand light years away.
His research is based on the latest available data from Kepler, an exoplanet hunting telescope launched by NASA in 2009. To date, this observatory has revealed nearly 1,000 planets in 400 star systems, with a further 3,200 unconfirmed candidates. These range in size from small and Earthlike, to rocky "super Earths" with high gravity, to enormous "hot Jupiters" in close proximity to their parent star.
While the sample size is tiny compared to the 100 billion+ total planets in our galaxy, it has nevertheless provided useful scientific data, allowing us to extrapolate some interesting estimates. Wandel has taken these figures and inputted them into the Drake Equation, to calculate the most realistic expectation of life elsewhere in our galaxy.
The Drake Equation is a famous mathematical formula devised by the American Frank Drake in 1961. It uses several different variables to produce "N" – representing the number of intelligent civilisations with active radio communications in our galaxy.
R* = The rate of formation of stars suitable for the development of intelligent life.
fp = The fraction of those stars with planetary systems.
ne = The number of planets, per solar system, with an environment suitable for life.
fl = The fraction of suitable planets on which life actually appears.
fi = The fraction of life bearing planets on which intelligent life emerges.
fc = The fraction of civilisations that develop a technology that releases detectable signs of their existence into space.
L = The length of time such civilisations release detectable signals into space.
Until recently, there was little or no data to constrain the parameters in this formula. Now that Kepler and other telescopes are illuminating our region of the galaxy, astronomers are gaining at least some idea of how exoplanets are distributed in terms of size, mass, densities, orbits, composition and atmospheric characteristics. They are beginning, for the first time, to narrow the possible range of values in the Drake equation. For instance, it is now likely that a typical star has on average a minimum of one planet. Around 1 in 5 Sun-like stars have an "Earth-sized" planet within their habitable zone and the nearest of these is expected to be within 12 light years of Earth.
Scatter plot of mass, m, and semimajor axis, a, for exoplanet discoveries as of 2014, indicating the discovery method using distinct colours: radial velocity (dark blue), transit (dark green), timing (dark purple), direct imaging (dark red), microlensing (dark orange)
Using the latest available data, Wandel estimated the distribution of life-bearing worlds in our part of the universe. His calculation suggests there are likely to be millions or even billions of planets with simple life forms (i.e. resembling a single-celled amoeba) in the Milky Way, the closest being somewhere between 10-100 light years from Earth. Intelligent life is much rarer, the nearest such world likely to be a few thousand light years distant.
That's assuming alien biology is at least somewhat predictable and similar to life here on Earth, of course – his estimate may be conservative. Silicon or ammonia-based life, for example, could use entirely different chemical structures unlike anything seen on our world. What may appear at first glance to be a "pebble" lying on the beach might, on closer inspection, turn out to be alive. Or there could be "living clouds" made of gaseous material.
Michio Kaku, in his 2008 book Physics of the Impossible, offers his thoughts on the matter. The majority of alien creatures, according to him, would be limited in size by the laws of physics. After a certain point is reached, the ratio of size:mass becomes so unbalanced that an object soon collapses under its own weight. Assuming a biology at least somewhat similar to our own, organisms would be unlikely to grow much larger than dinosaurs. The largest ever dinosaur is thought to have been Amphicoelias fragillimus, a sauropod which may have grown to a length of 60 m (196 ft).
As for advanced intelligence, futurist Ray Kurzweil says it is unlikely that a Star Trek-style universe exists. He divides the evolution of life into six epochs with exponential progress in the later stages. If his model is true, a civilisation with biological intelligence will transcend rapidly into post-biological form and reach "Singularity"-type status in a relatively short time. A scenario involving two biological intelligences meeting each other – like that between humans, Vulcans and other races – therefore seems improbable.
There are still many uncertainties, with astrobiology and exoplanet science in their infancy, but progress is clearly accelerating now as shown by Wendel's study and others. Further refinements of the Drake equation will emerge in the near future, as exponentially growing data is pieced together by astronomers to form an increasingly accurate picture of the galaxy and our place within it.
Future space telescopes will be far more powerful than Kepler – vastly increasing the tally of confirmed worlds and offering detailed analyses of exoplanets and their atmospheres. In fact, Kepler itself has already provided a hint of what lies ahead, having assisted in producing the first cloud map of an exoplanet last year. NASA is launching a mission called TESS in 2017, while ESA is deploying Cheops in the same year and PLATO from 2024-2030. New techniques used with ground-based telescopes should also help in characterising the many expected discoveries, possibly revealing biosignatures.
A spacecraft that will take humans to Mars in the 2030s had its first unmanned test flight today.
A major step on the long road to human exploration of Mars was achieved today, as NASA conducted the first test flight of Orion. This new spacecraft was launched from Cape Canaveral in eastern Florida at 07:05 EST (12:05 UTC) aboard a Delta IV Heavy rocket. It accomplished a series of milestones as it jettisoned a set of fairing panels around the service module, before the launch abort system (LAS) pulled itself away from the craft as planned.
Orion and the second stage of the rocket settled into an initial orbit around 17 minutes after lift-off. Flight controllers put them into a slow roll to keep temperatures controlled while they flew through a 97-minute coast phase. This was followed by upper stage separation and disposal, then splashdown and recovery in the eastern Pacific Ocean.
During four and a half hours of total flight time, Orion made two orbits of Earth, achieving a peak altitude of 3,600 miles (5,800 km), or about 13 times higher than the International Space Station. This high altitude enabled the craft to achieve reentry speeds of 20,000 mph (32,000 km/h; 8,900 m/s), which exposed the heat shield to temperatures up to 4,000°F (2,200°C), or 80% of the temperature that would be experienced upon reentry from a Moon mission.
This was an unmanned test, but Orion will eventually carry astronauts farther into space than has ever been possible before. Data from today's flight will be analysed by the Critical Design Review in April 2015. Alongside this, a massive new rocket – the Space Launch System (SLS) – is being developed to carry payloads of 70 metric tons, with a later version capable of 130 tons. The SLS will perform its first test launch by 2018, with a manned flight around the Moon planned for 2021 and exploration of an asteroid in the early 2020s. If all goes according to plan, the SLS in combination with Orion will send humans to Mars in the 2030s – the first time humanity has set foot on another celestial body since the Apollo era.
The effects of radiation will be critically important in assessing the safety of Orion. Mission planners will analyse the doses recorded inside the cabin on this and future tests, helping to refine the spacecraft's design and evaluate the best way of sending astronauts into deep space. Over 1,200 sensors were placed throughout the crew module to measure all elements of the spacecraft and the details of their performance.
"We're already working on the next capsule," said Mike Hawes, Lockheed Martin's Orion program manager, the company that built Orion and operated the flight for NASA. "We'll learn a tremendous amount from what we did today."
Rex Waldheim, who flew on the very last shuttle mission in 2011, told the BBC: "The people that are actually going to fly in Orion – I just can't imagine the thrill they're going to have when they sit here at the Kennedy Space Centre atop the rocket, ready to go to the Moon or to Mars or an asteroid – these incredible destinations. It's just going to be spectacular."
The Japan Aerospace Exploration Agency (JAXA) has successfully launched its Hayabusa 2 spacecraft. The mission blasted off at 13:22 local time on Wednesday 3rd December from Tanegashima Space Centre.
The probe will travel to an Apollo asteroid known as 1999 JU3. Upon arrival in 2018, a small explosive device will be launched towards the surface with enough force to produce a new crater. The aim is to investigate the composition of the rock and detect any organic materials or water contained inside. Like the current Rosetta mission at comet 67P, this could reveal new clues about the origins and formation of the Solar System.
A deployable camera (DCAM3), will observe the explosion and its aftermath. Three rovers (collectively called Minerva II) and a small lander known as MASCOT (Mobile Asteroid Surface Scout) will then conduct surface operations – using a range of instruments including an infrared spectrometer, magnetometer, radiometer and cameras. Samples will be obtained and returned to the main craft, with surveys continuing for a year and a half before it departs in 2019 and returns its cargo to Earth in 2020.
In a description of the Hayabusa 2 mission, JAXA explains as follows: "An asteroid is considered to have information about the birth of the Solar System and its later evolution. For a large celestial body such as Earth, its original materials were melted once, and consequently there is no way to reach the history before melting. On the other hand, most of the hundreds of thousands of asteroids and comets which we found at this point preserve history of the place and era of their birth within the Solar System."
The birth of planets has been revealed in astonishing detail by a telescope with 10 times the resolution of Hubble.
The Atacama Large Millimetre Array (ALMA) is a new radio telescope in northern Chile that became fully operational in 2013. Costing $1.4 billion, it is the most expensive ground-based telescope in the world, and the most sensitive at millimetre and submillimetre wavelengths. A cluster of 66 high-precision antennas work in unison to achieve phenomenal resolution.
ALMA was designed to open an entirely new "window" on the universe. Its capabilities have been demonstrated once again with a stunning image released by astronomers this week, showing extraordinarily fine detail in the planet-forming disk around a young star. These new results are a major step forward in the understanding of protoplanetary disks and the formation of planets.
HL Tau is a million-year-old Sun-like star, located 450 light-years from Earth in the constellation of Taurus. The photo seen here exceeds all expectations and reveals a series of concentric and bright rings, separated by gaps. These new substructures have never been seen before and are believed to show the possible positions of planets forming in the dark patches – similar to how our own Solar System would have looked more than 4 billion years ago.
ALMA Deputy Director, Stuart Corder: "These features are almost certainly the result of young planet-like bodies forming in the disk. This is surprising, since such young stars are not expected to have large planetary bodies capable of producing the structures we see in this image."
Catherine Vlahakis, Deputy Program Scientist: "When we first saw this image, we were astounded at the spectacular level of detail. HL Tauri is no more than a million years old, yet already its disk appears to be full of forming planets. This one image alone will revolutionise theories of planet formation."
ALMA's new high-resolution capabilities were achieved by spacing the antennas up to 15 kilometres apart. This baseline at millimetre wavelengths enabled a resolution of 35 milliarcseconds – equivalent to a penny seen from over 110 kilometres away. An even larger cluster of telescopes known as the Square Kilometre Array is planned for operation in 2024. This will have 50 times the resolution of ALMA and 500 times that of Hubble.
In August, the European Space Agency (ESA) achieved a major success when its Rosetta probe rendezvoused with comet 67P. The spacecraft has been returning spectacular images of this strange little world, located midway between the orbits of Mars and Jupiter. Among its latest photographs is the image below showing what appear to be dunes like those found on the deserts and beaches of Earth. Seen from a distance of about 8.8 km (5.5 miles), the scale here is 92 cm/pixel, meaning the dunes are roughly the width of a jumbo jet (as shown in this helpful illustration from Reddit).
The comet is already becoming more active as it approaches the Sun, with jets of dust shooting outward in slowly increasing quantities. Data from the mass spectrometers on Rosetta show that its coma (or atmosphere) contains a surprisingly rich variety of chemicals. Although low density, this would smell terrible, were humans able to experience it.
A surface lander is due to touch down on 12th November. Philae will take seven hours to land and is equipped with a 1024 x 1024 pixel CCD. If all goes according to plan, this will take images both during its final descent phase and on the surface, when the camera will be 30 cm above the ground. Its field of view will be roughly 30 x 30 cm, giving a resolution of 0.3 mm/pixel. You can follow the latest developments on the ESA blog (where many more images can be found) and via Twitter @ ESA_Rosetta.
Astronomers have detected what appears to be a signature of "axions" – dark matter particle candidates. If confirmed, this would be the first direct detection and identification of the elusive substance, which has been a mystery in physics for over 30 years.
XMM-Newton observatory. Credit: ESA
A landmark paper by Professor George Fraser – who tragically died earlier this year – and colleagues from the University of Leicester offers what is potentially the first direct detection of dark matter. This hypothetical form of matter comprises 85% of the Universe, but neither emits nor absorbs light or other electromagnetic radiation in any significant way. Its existence is only known because of the gravitational pull it has on objects. In other words, it is what holds everything together, and without it, galaxies would unravel and fly apart.
The study – to be published on 20th October in the Monthly Notices of the Royal Astronomical Society – looked at 15 years of measurements taken by the European Space Agency's orbiting XMM-Newton observatory; almost its entire archive of data. A curious signal was seen in the X-ray sky which had no conventional explanation, but is now believed to have been the result of axions. Previous searches for these particles, notably at CERN, and with other spacecraft in Earth orbit, have so far proved unsuccessful.
“The X-ray background – the sky, after the bright X-ray sources are removed – appears to be unchanged whenever you look at it,” says Dr. Andy Read from the University of Leicester's Department of Physics and Astronomy and now leading the paper. “However, we have discovered a seasonal signal in this X-ray background, which has no conventional explanation, but is consistent with the discovery of axions.”
As the late Professor Fraser explains in the paper: “It appears plausible that axions – dark matter particle candidates – are indeed produced in the core of the Sun and do indeed convert to X-rays in the magnetic field of the Earth.”
A sketch (not to scale) showing axions (blue) streaming out from the Sun, converting in the Earth's magnetic field (red) into X-rays (orange), which are then detected by the XMM-Newton observatory. Credit: University of Leicester
It is predicted that the X-ray signal due to axions will be greatest when looking through the sunward side of the magnetic field, because this is where the field is strongest. Each of these ghostly particles is extraordinarily light, with a vanishingly small mass just 1/100 billionth that of an electron or a million times less than a neutrino.
Dr. Read concludes: “These exciting discoveries, in George's final paper, could be truly ground-breaking, potentially opening a window to new physics, and could have huge implications, not only for our understanding of the true X-ray sky, but also for identifying the dark matter that dominates the mass content of the cosmos.”
President of the Royal Astronomical Society, Professor Martin Barstow: “This is an amazing result. If confirmed, it will be first direct detection and identification of the elusive dark matter particles and will have a fundamental impact on our theories of the Universe.”
We may know a lot more about dark matter in the coming years – thanks to a string of new observatories including the Euclid Space Telescope (2020), the European Extremely Large Telescope (2022) and the Advanced Technology Large-Aperture Space Telescope (2025). Dr. Read's team also plans to double the dataset from XMM-Newton and look at the results with more precision over the next few years.
NASA has announced finding several Kuiper Belt Objects that may be targeted by the New Horizons spacecraft, following its flyby of the Pluto system in July 2015.
Peering into the dim, outer reaches of our Solar System, NASA's Hubble Space Telescope has uncovered three Kuiper Belt Objects (KBOs) that the agency's New Horizons spacecraft could potentially visit after it flies by Pluto in July 2015. The KBOs were detected by a search team who were awarded telescope time for this purpose, following a committee recommendation earlier this year.
"This has been a very challenging search, and it's great that in the end Hubble could accomplish a detection — one NASA mission helping another," said Alan Stern of the Southwest Research Institute (SwRI) in Boulder, Colorado, principal investigator of the New Horizons mission.
The Kuiper Belt is a vast rim of primordial debris encircling our Solar System. KBOs belong to a unique class of Solar System objects that has never been visited by spacecraft and which contain clues to the origin of our Solar System.
The KBOs that Hubble found are each about 10 times larger than typical comets, but only about 1-2 percent of the size of Pluto. Unlike asteroids, KBOs have not been heated by the Sun, and are thought to represent a pristine, well preserved, deep-freeze sample of what the outer Solar System was like following its birth 4.6 billion years ago. The KBOs found in the Hubble data are thought to be the building blocks of dwarf planets such as Pluto.
The New Horizons team started to look for suitable KBOs in 2011 using some of the largest ground-based telescopes on Earth. They found several dozen KBOs, but none were reachable within the fuel supply available aboard the New Horizons spacecraft.
"We started to get worried that we could not find anything suitable – even with Hubble – but in the end, the space telescope came to the rescue," said team member John Spencer of SwRI. "There was a huge sigh of relief when we found suitable KBOs; we are 'over the moon' about this detection."
Following an initial proof of concept of the Hubble pilot observing program in June, the New Horizons team was awarded telescope time by the Space Telescope Science Institute for a wider survey in July. When the search was completed in early September, the team identified one KBO that is "definitely reachable" and two other potentially accessible KBOs that will require more tracking over several months to know whether they too are accessible by the New Horizons spacecraft.
This was a needle-in-a-haystack search for the New Horizons team, because the elusive KBOs are extremely small, faint, and difficult to pick out against myriad background stars in the constellation Sagittarius, which is in the present direction of Pluto. The three KBOs identified are each 1 billion miles beyond Pluto. Two of the KBOs are estimated to be as large as 34 miles (55 km) across, and the third is perhaps as small as 15 miles (25 km).
The New Horizons spacecraft, launched in 2006 from Florida, is the first mission in NASA's New Frontiers Program. Once a NASA mission completes its prime mission, the agency conducts an extensive science and technical review to determine whether extended operations are warranted.
The New Horizons team expects to submit such a proposal to NASA in late 2016 for an extended mission to fly by one of the newly identified KBOs. Hurtling across the Solar System, the New Horizons spacecraft would reach the distance of 4 billion miles from the Sun roughly three to four years after its July 2015 Pluto encounter. Accomplishing such a KBO flyby would substantially increase the science return from the New Horizons mission.
New measurements reveal there is half as much dark matter in our galaxy as previously thought, solving the 15-year-old "missing satellite galaxy" problem.
Credit: ESO/L. Calçada
New measurements of dark matter in our own Milky Way galaxy reveal there is half as much of the mysterious substance as previously thought. Astronomers from the International Centre for Radio Astronomy Research (ICRAR) used a method developed almost 100 years ago to discover that the weight of dark matter in our galaxy is 800 billion (or 8 x 1011) times the mass of the Sun. They probed the edge of the Milky Way, looking closely, for the first time, at the fringes about 5 million trillion kilometres from Earth.
Astrophysicist Dr Prajwal Kafle said we have known for a while that most of the Universe is hidden:“Stars, dust, you and me, all the things that we see, only make up about 4 per cent of the entire Universe. About 25 per cent is dark matter and the rest is dark energy.”
Dr Kafle was able to measure the mass of the dark matter in the Milky Way by studying the speed of stars throughout the galaxy, including the edges, which had never been studied in this detail before. He used a robust technique developed by British astronomer James Jeans in 1915 – decades before the discovery of dark matter. This new calculation helps to solve a mystery that has been haunting theorists for almost two decades.
“The current idea of galaxy formation and evolution – called the Lambda Cold Dark Matter theory – predicts that there should be a handful of big satellite galaxies around the Milky Way that are visible with the naked eye, but we don’t see that,” Dr Kafle said. “When you use our measurement of the mass of dark matter, the theory predicts that there should only be three satellite galaxies out there, which is exactly what we see; the Large Magellanic Cloud, the Small Magellanic Cloud and the Sagittarius Dwarf Galaxy.”
University of Sydney astrophysicist Prof. Geraint Lewis, who was also involved in the research, said the missing satellite problem had been “a thorn in the cosmological side for almost 15 years.”
“Dr Kafle’s work has shown that it might not be as bad as everyone thought, although there are still problems to overcome," he said.
The study also presented a holistic model of the Milky Way, which allowed the scientists to calculate several interesting factors, such as the speed required to leave the galaxy.
“Be prepared to hit 550 kilometres per second if you want to escape the gravitational clutches of our galaxy,” Dr Kafle said. “A rocket launched from Earth needs just 11 kilometres per second to leave its surface.”
In a star-forming cloud near the galactic core, chemicals have been discovered that are more similar to amino acids – the building blocks of life – than any previous finding. Furthermore, these are present in abundant quantities.
For the first time, astronomers have detected a carbon-bearing molecule with a "branched" structure in interstellar space. Iso-propyl cyanide (i-C3H7CN) was discovered in a giant gas cloud known as Sagittarius B2, a dense region of star formation measuring 150 light years across, located 390 light years from the centre of the Milky Way.
An international team from the Max Planck Institute for Radio Astronomy (Germany), University of Cologne (Germany) and Cornell University (USA) made the discovery using the Atacama Large Millimeter Array (ALMA) in Chile, which became operational in March 2013. Twenty of the observatory's 12m radio telescopes were aligned towards the galactic core – about 27,000 light years from Earth.
"Thanks to the new capabilities offered by ALMA, we were able to perform a full spectral survey toward Sagittarius B2 at wavelengths between 2.7 and 3.6 mm, with sensitivity and spatial resolution ten times greater than our previous survey," says Arnaud Belloche, lead author of the study. "But this took only a tenth of the time."
The carbon atoms in the molecule feature a branched structure that is unlike the straight-chain backbone of other molecules detected so far. This opens a new frontier in the complexity of molecules found within star-forming regions, and bodes well for the presence of amino acids, for which this branched structure is a key characteristic. While various types of molecules have been detected in space, the hydrogen-rich and carbon-bearing (organic) molecules that are most similar to the ones necessary for life on Earth seem to be most common in the gas clouds where new stars are formed.
"Understanding the production of organic material at the early stages of star formation is critical to piecing together the gradual progression from simple molecules to potentially life-bearing chemistry," says Belloche.
The search for organic molecules in space began in the 1960s, and 180 different molecular species have been discovered so far. Each type of molecule emits light at particular wavelengths, in its own characteristic pattern, acting like a fingerprint that allows it to be detected using radio telescopes.
Until now, the organic molecules discovered in star-forming regions have shared one major structural characteristic: they each consist of a "backbone" of carbon atoms that are arranged in a single and more or less straight chain. The new molecule discovered by the team, iso-propyl cyanide, is unique in that its underlying carbon structure branches off in a separate strand.
"This is the first ever interstellar detection of a molecule with a branched carbon backbone," says co-author Holger Müller, University of Cologne.
In addition to its structure, the researchers were also surprised by its abundance in this region – it was found to be plentiful, at almost half the concentration of its straight-chain sister molecule (normal-propyl cyanide), which the team had already detected a few years ago.
Robin Garrod, an astrochemist at Cornell University: "The enormous abundance of iso-propyl cyanide suggests that branched molecules may in fact be the rule, rather than the exception, in the interstellar medium."
"Amino acids identified in meteorites have a composition that suggests they originate in the interstellar medium," adds Belloche. “Although no interstellar amino acids have yet been found, interstellar chemistry may be responsible for the production of a wide range of important complex molecules that eventually find their way to planetary surfaces."
"The detection of iso-propyl cyanide tells us that amino acids could indeed be present in the interstellar medium, because the side-chain structure is a key characteristic of these molecules", says Karl Menten, director at Max Planck. "Amino acids have already been identified in meteorites and we hope to detect them in the interstellar medium in the future."
India's first probe to Mars – Mangalyaan – successfully entered orbit at 02:00 UTC this morning.
By Nesnad (Own work), CC-BY-SA-3.0 via Wikimedia Commons
Just three days after NASA's MAVEN mission, the Indian Space Research Organisation (ISRO) has successfully delivered its first unmanned craft to Mars, becoming only the fourth agency to do so. Launched in November 2013, the Mars Orbiter Mission (MOM), also called Mangalyaan ("Mars-craft") was developed at a cost of only $74 million, nine times less than the $671 million spent on NASA's effort. This morning, after a journey of 422 million miles (680 million km), MOM fired its main motors along with eight smaller engines to reduce its velocity as it approached the Red Planet, before entering into a highly elliptical orbit of 261 x 48,000 miles (421 x 77,000 km).
In the coming weeks, the spacecraft will be thoroughly tested to ensure it is fully functional, before commencing observations of the planet using a suite of five scientific instruments: a Lyman-alpha photometer, methane sensor, exospheric neutral composition analyser, thermal infrared imaging and a colour camera providing images in the visual spectrum. With a mission duration of six months, it will study Mars' surface features, morphology, mineralogy, atmosphere and weather systems. It has autonomous features to handle contingency situations.
Including MOM, a total of five satellites are now actively orbiting Mars. The others are MAVEN (US), Mars Odyssey (US), Mars Reconnaissance Orbiter (US) and Mars Express (Europe). In addition, two rovers are operational on the surface – Opportunity and Curiosity.
The Prime Minister of India, Narendra Modi, applauded those who achieved the historic rendezvous: "Today, all of India should celebrate our scientists. Schools, colleges should applaud this. If our cricket team wins a tournament, the nation celebrates. Our scientists' achievement is greater."
Mars missions have been notorious for their high failure rate. India has now become the first country to make it to Mars on its first attempt: "The odds were stacked against us," added Modi. "Of the 51 missions attempted across the world so far, a mere 21 had succeeded. But we have prevailed."
ISRO plans to send a follow-up mission with a greater scientific payload in the 2017-2020 timeframe; this will include an orbiter and a stationary lander. Several other missions are planned by NASA and Europe. Another country with ambitions to reach Mars is the United Arab Emirates (UAE), which plans to send a spacecraft in 2021.
You can follow India's Mars mission on Twitter @ MarsOrbiter.
The latest mission to Mars will attempt to uncover new clues about why the planet lost its atmosphere and surface water billions of years ago.
Another entry on our timeline is becoming a reality, as the Mars Atmosphere and Volatile EvolutioN (MAVEN) probe has successfully entered Mars' orbit. Launched by an Atlas V rocket in November 2013, the spacecraft travelled 442 million miles (711 million km) to reach its destination. As it approached the Martian north pole last night, MAVEN performed a 33-minute burn to reduce its speed, a manoeuvre that consumed over half its fuel. This allowed it to be captured by the planet's gravity and inserted into an elliptical orbit, with arrival confirmed shortly before 0230 GMT (2230 EDT Sunday; 0330 BST).
Using a total of eight instruments, MAVEN will now begin studying the Red Planet’s upper atmosphere and its interactions with the solar wind. There is strong evidence that Mars once possessed a denser atmosphere and higher temperatures, allowing vast amounts of liquid water on the surface – possibly including a large ocean that covered one-third of the planet. These conditions may even have been suitable for life to emerge. At some point in the distant past, however, Mars lost 99% of its atmosphere to space. It is theorised that over millions of years, the planet's core began to cool and its magnetic field decayed, allowing the solar wind to sweep away most of the water and volatile compounds that the atmosphere once contained.
The goal of MAVEN is to determine the history of the Martian atmosphere and its climate evolution. By measuring the rate at which gases are currently escaping to space and gathering knowledge about the relevant processes, researchers will be able to infer how the atmosphere changed over time. During the next twelve months, a series of "deep dips" will occur at 77 miles (125 km) minimum altitude to sample the upper atmosphere. This data will provide information down to where the upper and lower atmospheres meet, giving scientists a full profile of the upper tier.
MAVEN is the first probe to study the tenuous upper atmosphere of Mars in such detail. It will also examine the Sun's influence, looking at how much energy it puts into the planet and its climate. By chance, a comet will pass extremely close to Mars next month, offering a rare opportunity to see how incoming water and other molecules affect the physical processes. You can follow the mission progress at nasa.gov/maven and Twitter/MAVEN2Mars.
Artist's impression of what ancient Mars may have looked like, based on geological data. Credit: Ittiz [CC-BY-SA-3.0]
Since the retirement of the Space Shuttle fleet in 2011, NASA has been reliant on Russia for delivering manned flights to low-Earth orbit. The agency has been charged upwards of $70 million per person for rides on Russian Soyuz capsules. Russia's monopoly on space transportation looks set to end, however, as two major contracts worth $6.8 billion have just been awarded to Boeing and SpaceX.
From 2017, SpaceX's Falcon 9 launch vehicle and Dragon spacecraft – alongside Boeing's Crew Space Transportation (CST)-100 – will deliver astronauts to the International Space Station (ISS). Prior to these services, the contracts will include at least one crewed test flight per company. Once the launch, manoeuvring and docking systems have been validated, as many as six crewed missions will be undertaken by each company. These spacecraft will also serve as lifeboats for astronauts aboard the ISS.
According to NASA Administrator Charlie Bolden, turning over low-Earth orbit transportation to private industry will allow NASA to focus on an even more ambitious mission – sending humans to Mars. The agency recently completed a review of its Space Launch System, the rocket intended to carry humans to the Red Planet, and has reaffirmed its commitment to achieving this goal during the 2030s.
Astronomers have discovered the first evidence of water ice clouds on an object outside our own Solar System.
W0855 is the fourth closest system to our Sun, at 7.3 light-years away. In this illustration, the Sun is the bright star directly to the right of the brown dwarf. The slightly shifted star field accurately reflects how the sky around the constellations of Aquila and Delphinus would appear from this vantage point.
Scientists at the Carnegie Institution of Washington report the first evidence of water ice clouds on a body outside of our own Solar System. Water ice clouds are present on the gas giants – Jupiter, Saturn, Uranus, and Neptune – but have never been seen outside the planets orbiting our Sun until now. This finding is published by The Astrophysical Journal Letters.
At the Las Campanas Observatory in Chile, a near-infrared camera was used to detect WISE 0855–0714 (also called W0855) a tiny sub-brown dwarf located approximately 7.3 light years from Earth. This was first seen by a NASA space telescope – Wide-Field Infrared Survey Explorer – and confirmed in April 2014. But it was not known if the object could be seen by ground-based facilities. The Carnegie researchers managed to obtain 151 images from Las Campanas over a period of three nights.
"This was a battle at the telescope to get the detection," said Jacqueline Faherty, who led the study.
Chris Tinney, co-author on the result, stated: "This is a great result. This object is so faint and it’s exciting to be the first people to detect it with a telescope on the ground."
Brown dwarfs are too small to be classified as stars, but too large to be considered planets. Because of their size, they are too small to sustain the hydrogen fusion process that fuels stars. Their temperatures can range from nearly as hot as a star to as cool as a planet, and their masses also range between star-like and giant planet-like. They are of particular interest to scientists because they offer clues to star-formation processes. They also overlap with the temperatures of planets, but are much easier to study since they are commonly found in isolation.
W0855 is the fourth closest system to our own, practically next door in terms of astronomical distances. It is also the coldest object of its type found in interstellar space, having a temperature between 225 to 260 K (−48 to −13°C; −55 to 8°F). A comparison of near-infrared images of W0855 with models for predicting the atmospheric content of brown dwarfs showed evidence of frozen clouds of sulfide and water.
"Ice clouds are predicted to be very important in the atmospheres of planets beyond our Solar System, but they've never been observed outside of it before now," Faherty said.
The next generation of telescopes – such as the E-ELT (2022), PLATO observatory (2024-2030) and the ATLAST project (2025-2035) – will provide more detailed views of planets' and brown dwarfs' atmospheres.