New infrared images of Uranus show details not seen before. Credit: NASA/ESA/L. A. Sromovsky/P. M. Fry/H. B. Hammel/I. de Pater/K. A. Rages
Here’s the scene: a thick, tempestuous atmosphere with winds blowing at a clip of 900 km/h (560 mph); massive storms that would engulf continents here on Earth, and temperatures in the -220 C (-360 degree F) range. Sounds like a cold Hell, but this is the picture emerging of the planet Uranus, revealed in new high-resolution infrared images from the Keck Observatory in Hawaii, exposing in incredible detail the bizarre weather of a planet that was once thought to be rather placid.
“My first reaction to these images was ‘wow’ and then my second reaction was ‘WOW,'” said Heidi Hammel, a co-investigator on the new observations. “These images reveal an astonishing amount of complexity in Uranus’ atmosphere. We knew the planet was active, but until now much of the activity was masked by noise in our data.”
Voyager 2’s view of Uranus. Credit: NASA
With its beautiful blue atmosphere, Uranus can seem rather tranquil at first glance. Even the flyby of Voyager 2 in 1986 revealed a rather “bland” blue ball. But coming into focus now with the new are large weather systems, and even though they are probably much less violent than storms on Earth, the weather on Uranus is just…bizarre.
“Some of these weather systems,” said Larry Sromovsky, from the University of Wisconsin-Madison who led the new study using the Keck II telescope, “stay at fixed latitudes and undergo large variations in activity. Others are seen to drift toward the planet’s equator while undergoing great changes in size and shape. Better measures of the wind fields that surround these massive weather systems are the key to unraveling their mysteries.”
Sromovsky, Hammel and their colleagues are using new infrared techniques to deliver some of the “most richly detailed views of Uranus yet obtained by any instrument on any observatory. No other telescope could come close to producing this result,” Sromovsky said.
What they are seeing are previously undetected, small but widely distributed weather feature, and they hope the movements of these features can help make sense of the planet’s odd pattern of winds.
They observed a scalloped band of clouds just south of Uranus’ equator and a swarm of small convective features in the north polar regions of the planet. Features like this don’t seem to be in the southern polar regions, but are similar to the types of “popcorn” –type clouds seen on Saturn. Uranus’ north pole is not visible from Earth night now, but when it does come into view, the researchers wouldn’t be surprised to see a polar vortex feature similar to what has been seen at Saturn’s south pole.
The driver of these features must be solar energy because there is no other detectable internal energy source.
“But the Sun is 900 times weaker there than on Earth because it is 30 times further from the Sun, so you don’t have the same intensity of solar energy driving the system,” said Sromovsky. “Thus the atmosphere of Uranus must operate as a very efficient machine with very little dissipation. Yet the weather variations we see seem to defy that requirement.”
One possible explanation, is that methane is pushed north by an atmospheric conveyor belt toward the pole where it wells up to form the convective features visible in the new images. The phenomena may be seasonal, the team said, but they are still working on trying to put together a clear seasonal trend in the winds of Uranus.
“Uranus is changing,” he said, “and there is certainly something different going on in the two polar regions.”
The images were released at the American Astronomical Society’s Division for Planetary Sciences meeting taking place this week.
Caption: Artist’s impression of ESA’s orbiting gamma-ray observatory Integral. Image credit: ESA
Integral, ESA’s International Gamma-Ray Astrophysics Laboratory launched ten years ago this week. This is a good time to look back at some of the highlights of the mission’s first decade and forward to its future, to study at the details of the most sensitive, accurate, and advanced gamma-ray observatory ever launched. But the mission has also had some recent exciting research of a supernova remnant.
Integral is a truly international mission with the participation of all member states of ESA and United States, Russia, the Czech Republic, and Poland. It launched from Baikonur, Kazakhstan on October 17th 2002. It was the first space observatory to simultaneously observe objects in gamma rays, X-rays, and visible light. Gamma rays from space can only be detected above Earth’s atmosphere so Integral circles the Earth in a highly elliptical orbit once every three days, spending most of its time at an altitude over 60 000 kilometres – well outside the Earth’s radiation belts, to avoid interference from background radiation effects. It can detect radiation from events far away and from the processes that shape the Universe. Its principal targets are gamma-ray bursts, supernova explosions, and regions in the Universe thought to contain black holes.
5 metres high and more than 4 tonnes in weight Integral has two main parts. The service module is the lower part of the satellite which contains all spacecraft subsystems, required to support the mission: the satellite systems, including solar power generation, power conditioning and control, data handling, telecommunications and thermal, attitude and orbit control. The payload module is mounted on the service module and carries the scientific instruments. It weighs 2 tonnes, making it the heaviest ever placed in orbit by ESA, due to detectors’ large area needed to capture sparse and penetrating gamma rays and to shield the detectors from background radiation in order to make them sensitive. There are two main instruments detecting gamma rays. An imager producing some of the sharpest gamma-ray images and a spectrometer that gauges gamma-ray energies very precisely. Two other instruments, an X-ray monitor and an optical camera, help to identify the gamma-ray sources.
During its extended ten year mission Integral has has charted in extensive detail the central region of our Milky Way, the Galactic Bulge, rich in variable high-energy X-ray and gamma-ray sources. The spacecraft has mapped, for the first time, the entire sky at the specific energy produced by the annihilation of electrons with their positron anti-particles. According to the gamma-ray emission seen by Integral, some 15 million trillion trillion trillion pairs of electrons and positrons are being annihilated every second near the Galactic Centre, that is over six thousand times the luminosity of our Sun.
A black-hole binary, Cygnus X-1, is currently in the process of ripping a companion star to pieces and gorging on its gas. Studying this extremely hot matter just a millisecond before it plunges into the jaws of the black hole, Integral has discovered that some of it might be escaping along structured magnetic field lines. By studying the alignment of the waves of high-energy radiation originating from the Crab Nebula, Integral found that the radiation is strongly aligned with the rotation axis of the pulsar. This implies that a significant fraction of the particles generating the intense radiation must originate from an extremely organised structure very close to the pulsar, perhaps even directly from the powerful jets beaming out from the spinning stellar core.
Just today ESA reported that Integral has made the first direct detection of radioactive titanium associated with supernova remnant 1987A. Supernova 1987A, located in the Large Magellanic Cloud, was close enough to be seen by the naked eye in February 1987, when its light first reached Earth. Supernovae can shine as brightly as entire galaxies for a brief time due to the enormous amount of energy released in the explosion, but after the initial flash has faded, the total luminosity comes from the natural decay of radioactive elements produced in the explosion. The radioactive decay might have been powering the glowing remnant around Supernova 1987A for the last 20 years.
During the peak of the explosion elements from oxygen to calcium were detected, which represent the outer layers of the ejecta. Soon after, signatures of the material from the inner layers could be seen in the radioactive decay of nickel-56 to cobalt-56, and its subsequent decay to iron-56. Now, after more than 1000 hours of observation by Integral, high-energy X-rays from radioactive titanium-44 in supernova remnant 1987A have been detected for the first time. It is estimated that the total mass of titanium-44 produced just after the core collapse of SN1987A’s progenitor star amounted to 0.03% of the mass of our own Sun. This is close to the upper limit of theoretical predictions and nearly twice the amount seen in supernova remnant Cas A, the only other remnant where titanium-44 has been detected. It is thought both Cas A and SN1987A may be exceptional cases
Christoph Winkler, ESA’s Integral Project Scientist says “Future science with Integral might include the characterisation of high-energy radiation from a supernova explosion within our Milky Way, an event that is long overdue.”
Find out more about Integral here
and about Integral’s study of Supernova 1987A here
Image caption: Time lapse context view of Curiosity maneuvering her robotic arm. Curiosity conducts a close- up examination of windblown ‘Rocknest’ ripple site and inspects sandy material at “bootlike” wheel scuff mark with the APXS (Alpha Particle X-Ray Spectrometer) and MAHLI (Mars Hand Lens Imager) instruments positioned on the rotatable turret at the arm’s terminus. Colorized mosaic was stitched together from Sol 57 & 58 Navcam raw images shows the arm in action just prior to 1st sample scooping here. Surrounding terrain and eroded rim of Gale Crater rim is visible on the horizon. Credit: NASA/JPL-Caltech/Ken Kremer/Marco Di Lorenzo
NASA’s Curiosity rover is actively searching for uncontaminated Martian soil after finding new flecks of “bright material” of unknown origin in the windblown sands at “Rocknest” ripple.
The team leading the Curiosity Mars Science Lab (MSL) mission decided to dump the second scoopful of dusty material collected last week on Sol 66 (Oct. 12). Instead they will search for pristine Martian sand to pour into the rover’s critical sample-processing mechanisms to use as a decontamination agent for cleansing the interior chambers and walls of Earthly residues.
Image Caption: Bright Particle of Martian Origin in Scoop Hole. This image contributed to an interpretation by NASA’s Mars rover Curiosity science team that some of the bright particles on the ground near the rover are native Martian material. Other light-toned material nearbyhas been assessed as small debris from the spacecraft. Curiosity’s Mars Hand Lens Imager (MAHLI) camera took this image on Sol 66 (Oct. 12, 2012) showing part of the hole or bite left in the ground when Curiosity collected its first scoop of Martian soil five sols earlier. A clod of soil near the top center of the image contains a light-toned particle. The observation that the particle is embedded in the clod led scientists to assess this particle as Martian material, not something from the spacecraft. This assessment prompted the mission to continue scooping in the area, despite observations of a few light-toned particles in the area being scooped. The image shows an area about 2 inches (5 centimeters) across. It is brightened to improve visibility in the shaded area. Credit: NASA/JPL-Caltech/MSSS
The science team is proceeding with appropriate caution – just as they indicated at press briefings – so as not to gum up the sample processing system with material that could give false positive readings for organic compounds or compromise the integrity of the rover’s delicate sample handling and delivery system.
“Concerns that the bright spot is more material shed from the flight system, and that some of this terrestrial material is in the scooped dirt, led the tactical team to decide to dump the scoop and take MAHLI images of the scoop targets first,” wrote MSL scientist Ken Herkenhoff in a rover team update.
The second scoopful of Martian sand from Rocknest was intentionally discarded on Sol 67 (Oct.13) after up close imaging by the MAHLI microscopic imaging camera revealed several specks of bright material that could be debris from the landing system or the rover itself or possibly even native Martian material.
The third test sample will be carefully analyzed by MAHLI, ChemCam and Mastcam and verified to be free of FOD before the team decides to pour the new processed sand into the processing system and eventually into the Sample Analysis at Mars (SAM) and Chemistry and Mineralogy (CheMin) analytical chemistry instruments on the rover deck.
Image Caption: Small Debris on the Ground Beside Curiosity – This image from the Mars Hand Lens Imager (MAHLI) camera on NASA’s Mars rover Curiosity shows a small bright object on the ground beside the rover at the “Rocknest” site about half an inch (1.3 centimeters) long. The rover team has assessed this object as debris from the spacecraft, possibly from the events of landing on Mars. The image was taken on Sol 65 (Oct. 11, 2012). Credit: NASA/JPL-Caltech/MSSS
Progress has been slowed somewhat by communications glitches with a radio transmitter at a Deep Space Network ground station and an unrelated new problem with NASA’s Mars Reconnaissance Orbiter (MRO) which went into “safe mode” on Sol 69. MRO serves as the highest volume communications relay for Curiosity’s images and scientific and engineering data.
Tosol is Sol 71 and Curiosity is now 10 weeks into her two year long mission to investigate whether Mars ever had conditions sufficient to sustain microbial life forms.
Curiosity made a pinpoint landing inside Gale Crater on Aug. 5/6, just a few miles away from her ultimate destination – the sedimentary lower layers of Mount Sharp holding deposits of hydrated minerals.
Video Caption: This 256 frame video clip shows the 1st sample of Martian material being vibrated inside Curiosity’s table spoon sized scoop on Oct. 7, 2012.
Here’s a fantastic timelapse compilation of space shuttle Endeavour’s big drive through the streets of Los Angeles. Photographer/cinematographer Matthew Givot and his team followed the shuttle during the 2-day ‘endeavor’ — a drive that included photo-ops of the shuttle driving past several well-known L.A. landmarks. There were also some tight squeezes and ‘back-up-and-start-over’ turns and corners. Driving a space shuttle through a metropolis like LA is a little more complicated than initially thought, as the trip took 17 hours longer than originally planned. But it’s obvious from the reactions of the crowds and the look on people’s faces that Endeavour will be well-loved in her new home.
Artist’s impression of an impact of two planet-sized worlds (NASA/JPL-Caltech)
Scientists have uncovered a history of violence hidden within lunar rocks, further evidence that our large, lovely Moon was born of a cataclysmic collision between worlds billions of years ago.
Using samples gathered during several Apollo missions as well as a lunar meteorite that had fallen to Earth (and using Martian meteorites as comparisons) researchers have observed a marked depletion in lunar rocks of lighter isotopes, including those of zinc — a telltale element that can be “a powerful tracer of the volatile histories of planets.”
The research utilized an advanced mass spectroscopy instrument to measure the ratios of specific isotopes present in the lunar samples. The spectrometer’s high level of precision allows for data not possible even five years ago.
Scientists have been looking for this kind of sorting by mass, called isotopic fractionation, since the Apollo missions first brought Moon rocks to Earth in the 1970s, and Frédéric Moynier, PhD, assistant professor of Earth and Planetary Sciences at Washington University in St. Louis — together with PhD student, Randal Paniello, and colleague James Day of the Scripps Institution of Oceanography — are the first to find it.
The team’s findings support a now-widely-accepted hypothesis — called the Giant Impact Theory, first suggested by PSI scientists William K. Hartmann and Donald Davis in 1975 — that the Moon was created from a collision between early Earth and a Mars-sized protoplanet about 4.5 billion years ago. The effects of the impact eventually formed the Moon and changed the evolution of our planet forever — possibly even proving crucial to the development of life on Earth.
(What would a catastrophic event like that have looked like? Probably something like this:)
“This is compelling evidence of extreme volatile depletion of the moon,” said Scripps researcher James Day, a member of the team. “How do you remove all of the volatiles from a planet, or in this case a planetary body? You require some kind of wholesale melting event of the moon to provide the heat necessary to evaporate the zinc.”
In the team’s paper, published in the October 18 issue of Nature, the researchers suggest that the only way for such lunar volatiles to be absent on such a large scale would be evaporation resulting from a massive impact event.
“When a rock is melted and then evaporated, the light isotopes enter the vapor phase faster than the heavy isotopes, so you end up with a vapor enriched in the light isotopes and a solid residue enriched in the heavier isotopes. If you lose the vapor, the residue will be enriched in the heavy isotopes compared to the starting material,” explains Moynier.
The fact that similar isotopic fractionation has been found in lunar samples gathered from many different locations indicates a widespread global event, and not something limited to any specific regional effect.
The next step is finding out why Earth’s crust doesn’t show an absence of similar volatiles, an investigation that may lead to clues to where Earth’s surface water came from.
“Where did all the water on Earth come from?” asked Day. “This is a very important question because if we are looking for life on other planets we have to recognize that similar conditions are probably required. So understanding how planets obtain such conditions is critical for understanding how life ultimately occurs on a planet.”
“The work also has implications for the origin of the Earth,” adds Moynier, “because the origin of the Moon was a big part of the origin of the Earth.”
Although space missions Voyager and Galileo observed evidence of volcanic activity on Io, it was a faint blue plume at the edge of Io’s limb in a highly-enhanced image from Voyager that first offered evidence of the moon’s turbulent nature.
You fancy yourself an armchair astronomer? A group of California researchers have stepped it up a notch by monitoring the intense volcanic eruptions on Jupiter’s strangest moon Io from the comfort of their home.
Io, the innermost of the four largest moons around Jupiter, or the Galilean moons, is the most volcanically active object in the Solar System with more than 400 active volcanoes spitting out plumes of sulfur and sulfur dioxide. Scientists think a gravitational tug-of-war with Jupiter is one cause of Io’s intense vulcanism. Researchers point out that most of the processes are not well understood. While Io’s eruptions can’t be seen directly from Earth, a team led by Frank Marchis, a researcher at the Carl Sagan Center of the SETI Institute have come up with an unique combination of Earth-based telescope arrays and archival imagery from the Voyager and Galileo probes, according to a press release. The team announced their findings at the 2012 Division of Planetary Sciences meeting today in Reno, Nevada.
“Since our first observation of Io in 2001 using the W. M. Keck II 10-m telescope from the top of Mauna Kea in Hawaii and its AO (adaptive optics) system, our group became very excited about the technology,” says Marchis. “We also began using AO at the Very Large Telescope in Chile, and at the Gemini North telescope in Hawaii. The technology has improved over the years, and the image quality and usefulness of those complex instruments has made them part of the essential instrument suite for large telescopes.”
A faint blue plume on a grainy and highly enhanced image from Voyager 1 first hinted at Io’s dynamic nature. Voyager’s cameras showed a bizarre terrain of volcanic fields, dark spots and active plumes. Scientists nicknamed it the “Pizza Moon.” NASA’s Galileo probe observed more than 160 active volcanoes in various stages of eruption during its looping tour of the solar system’s largest planet.
But crystal clear pictures from Galileo ceased in 2003. Observing a Moon-sized object at the incredible distance to Jupiter from Earth is a challenge because of the blurring caused by Earth’s stirring atmosphere. Since 2001, all large 8- to 10-meter telescopes have been equipped with adaptive optics that correct for that blur. Since 2003, Marchis and his team have gathered about 40 cycles of observations of Io in the near-infrared showing details as small as 100 kilometers, or 60 miles, on the surface of the moon.
Observations of several bright & young eruptions detected at short wavelengths (~2.1 microns) on the top and longer wavelengths (~3.2 microns) on the bottom since 2004 using the W. M. Keck 10-meter telescope (May 2004, Aug 2007, Sep 2007, July 2009), the Gemini North 8-meter telescope (Aug 2007), and the ESO VLT-Yepun 8-meter telescope (Feb 2007), all with their adaptive optics systems. The thermal signature of the Tvashtar outburst can be seen near the north pole on images collected in 2007. A new eruption on Pillan Patera was seen in Aug 2007. A young and bright eruption was detected on Loki Patera in July 2009. This is the last bright eruption that was detected in our survey; since then, Io’s volcanic activity has been quiescent. Credit: F. Marchis
“Spacecraft have only been able to capture fleeting glimpses of Io’s volcanoes, Voyager for a few months, Galileo a few years, and New Horizons a few days. Ground-based observations, on the other hand, can continue to monitor Io’s volcanoes over long time-scales. The more telescopes looking at Io, the better time coverage we can obtain.” Said Julie Rathbun from Redlands University, a planetary scientist not directly involved in this study but who has conducted monitoring of Io with NASA’s IRTF 3-meter telescope for more than 15 years. “AO observations from 8-10m class telescopes are a dramatic improvement in spatial resolution over previous ground-based observations. Soon they will not only be our only way to monitor Io’s volcanoes, but the best way. We should be making these observations more often.”
Simulation of observations of Io using the W. M. Keck telescope and its current AO system, a next-generation AO system mounted on the W. M. Keck telescope (KNGAO), and the Thirty Meter Telescope (TMT) equipped with its AO system (NFIRAOS). The spatial resolution on the center of Io provided by these AO systems is respectively 140 km, 110 km and 35 km in the H band (1.6 microns). Two young eruptive centers labeled A & B can be detected only on the TMT observations. The KNGAO instrument detected the brightest eruption labeled A. Credit: F. Marchis
According to the team, observations reveal a series of young and energetic eruptions called outbursts. These events stand out indicating a high eruption temperature. Coincidentally, the team observed the awakening of the volcano Tvashtar while New Horizons slingshot past Jupiter on its way to Pluto. The eruption lasted from April 2006 to September 2007. Older observations from Galileo show a similar eruption pattern in 1999 lasting for 15 months.
“The episodicity of these volcanoes points to a regular recharge of magma storage chambers” said Ashley Davies a volcanologist at the Jet Propulsion Laboratory, California Institute of Technology, and a member of the study. “This will allow us to model the eruption process and understand the how heat is removed from Io’s deep interior by this particular style of volcanic activity.”
The team found four additional eruptions including a previously unobserved active volcano in 2004. The new sporadic blast accounted for about 10 percent of Io’s average thermal output, according to Marchis. The outburst was more energetic than Tvashtar in 2001. While the team continues to study Io, they have noted that since September 2010, the crazily active moon has been mostly quiet. A dozen or so permanent, low temperature eruptions dot the globe but the team has not detected the young, fire fountain style eruptions seen before.
“The next giant leap in the field of planetary astronomy is the arrival of Giant Segmented Mirror Telescopes, such as the Thirty Meter Telescope expected to be available in 2021. It will provide a spatial resolution of 35 km in the near-infrared, equivalent to the spatial resolution of global observations taken by the Galileo spacecraft. When pointed at Io, these telescopes will offer the equivalent of a spacecraft flyby of the satellite,” Marchis said.
I was worried that the book “Information, Communication and Space Technology” had the potential to be ‘jack of all trades, master of none,’ as it promises to cover all aspects of ICT and space tech, all in 200-ish pages. But I needn’t have worried. Author Mohammad Razani delivers on the ambitious goal of presenting a high level picture on all topics of Information Communication Technology(ICT) and space technology.
Although at times it seems as though there is a distinct split between the ICT and the space tech content, the author presents his information in a manner which most tech-heads and gear-geeks would love. But this book is not for the average fiction-inclined reader. Some previous knowledge is required.
It begins with covering the very large topic of ICT in health, government and education. At times it feels as though this half of the book is there to balance to latter space tech half of the book, like a student presenting the ‘boring bits’ before going crazy about ‘space technologies!!!’. He does skim over some points a little, but this keeps it interesting and exciting because it doesn’t get bogged down in the fine details. This means the book is not too overwhelming, but it remains informative by presenting enough detail.
There is the potential for some of the content to be interpreted as opinion piece…which at times it kind of is. He presents arguments for further resources and investment into ICT in education, particularly in the USA, where he is an educational professional. However, it’s presented objectively and doesn’t read as though he is shouting from the soap box. And there are enough references cited for each point he makes to make each argument objective (if that is not an oxymoron). He presents cases studies, tables and stats for the numerically-minded readers and is a reflection of past ICT and statistics to dictate possible direction of future ICT. Mohammad Razani presents studies on what challenges there are in ICT for health, gov and education, and the possible future solutions through case studies. Not being previously familiar with a lot of the industries issues he covered, I’ve learnt a great deal.
The information presented was very detailed and pleasing for the techno-geek audience. But at times was difficult to understand the information the author uses for comparison. For example, tables on satellites from different agencies presented different measurements and specifications, making it like comparing apples with oranges.
And there seemed to be a couple of product placement mentions — e.g. the software workshop the author attended. Perhaps I am cynical, but it seemed to be like when a doctor presents a certain drug, because he gets kickbacks from the pharmaceutical company.
The space technology section was more well thought-out and exciting. You could tell that Mohammad Razani was more inspired by these topics. He gave a great background on the history and development of the space technology and satellites. The cool parts were definitely the brief scientific explanation of space flight, atmospheric studies and gravity. It kept the pages turning without becoming overwhelming. I felt I learnt a great deal without the aid of any other research or references.
Tip: start your own glossary to refer to. This reader would have benefited from a glossary, instead of having to refer to the index or re-read parts of the book where the definitions and explanations of acronyms and phrases were presented.
The highlights of this book were the scientific explanations of the relevant to content. If a reader was so inclined to do self-research on this topic, it would take them years to find all information presented in this book, without the guidance Mohammad Razani. As a reader, I am left with the hope that ICT could be used to advance all of humanity, rather than promote western culture alone. As a student this has inspired me to pursue this area of technology, as we have only just begun. It gives a great starting point for any interested readers to launch their own research and further reading. I will refer to this book for years to come. The hardcover is also a bonus!
If I had to give this book a rating, it would be 3.5 satellite dishes out of 5.
Artist’s impression of the planet around Alpha Centauri B. Credit: ESO
Artist’s impression of the planet around Alpha Centauri B. Credit: ESO
Astronomers have discovered an enticing new planet that could be considered our next-door neighbor. The planet is orbiting a star in the Alpha Centauri system — the closest system to our own, just 4.3 light years away — and the planet has a mass about the same as Earth. It is also the lightest exoplanet ever discovered around a sun-like star. While this planet is likely too hot to contain life as we know it, the star system could possibly host other worlds that could be habitable, researchers from the European Southern Observatory at La Silla say.
“This result represents a major step towards the detection of Earth twins in the immediate vicinity of the Sun,” the team wrote in their paper.
“This is the first planet with a mass similar to Earth ever found around a star like the Sun. Its orbit is very close to its star and it must be much too hot for life as we know it,” said Stéphane Udry from the Geneva Observatory, a co-author of the paper that will be published in Nature on Oct. 17, and member of the team that used the HARPS instrument to find the planet. “But it may well be just one planet in a system of several. Our other HARPS results, and new findings from Kepler, both show clearly that the majority of low-mass planets are found in such systems.”
The planet is called Alpha Centauri Bb and it whips around its star every 3.2 days, orbiting at a distance of just 6 million kilometers (3.6 million miles), closer than Mercury’s orbit around the Sun. (Earth orbits at a comfortable 150 million kilometers (93 million miles) from the Sun.) So it is likely very hot and covered with molten rock, the researchers say.
Many astronomers have thought that the Alpha Centauri system would be a perfect candidate to host Earth-sized worlds. In fact, in 2008, a team of astronomers ran computer simulations of the system’s first 200 million years, and in each instance, despite different parameters, multiple terrestrial planets formed around the star. In every case, at least one planet turned up similar in size to the Earth, and in many cases this planet fell within the star’s habitable zone.
But while astronomers have looked for years, previous searches of planets in the Alpha Centauri system came up empty.
Until now.
“Our observations extended over more than four years using the HARPS instrument and have revealed a tiny, but real, signal from a planet orbiting Alpha Centauri B every 3.2 days,” says Xavier Dumusque (Geneva Observatory, Switzerland and Centro de Astrofisica da Universidade do Porto, Portugal), lead author of the paper. “It’s an extraordinary discovery and it has pushed our technique to the limit!”
The European team detected the planet by using the radial velocity method — by picking up the tiny wobbles in the motion of the star Alpha Centauri B created by the gravitational pull of the orbiting planet. The effect is extremely small, as it causes the star to move back and forth by no more than 51 centimeters per second (1.8 km/hour). The team said this is the highest precision ever achieved using this method.
Alpha Centauri is one of the brightest stars in the southern skies and is actually a triple star — a system consisting of two stars similar to the Sun orbiting close to each other, designated Alpha Centauri A and B, and a more distant and faint red component known as Proxima Centauri.
Alpha Centauri B is very similar to the Sun but slightly smaller and less bright. The orbit of Alpha Centauri A is hundreds of times further away from the planet, but it would still be a very brilliant object in the planet’s skies.
A wide-field view of the sky around Alpha Centauri was created from photographic images forming part of the Digitized Sky Survey 2. The star appears so big just because of the scattering of light by the telescope’s optics as well as in the photographic emulsion. Credit: ESO
The first exoplanet around a Sun-like star was found by the same team back in 1995 and there are now 843 Exoplanets with the addition of Alpha Centauri Bb. Most are much bigger than Earth, and many are as big as Jupiter. The previous closest exoplanet was Epsilon Eridani b, 10.4 light years away.
The challenge astronomers now face is to detect and characterize a planet of mass comparable to the Earth that is orbiting in the habitable zone around another star. The first step has now been taken, the team says.
“This result represents a major step,” said Dumusque. “We live in exciting times!”
So, how long would it take for us to get to this planet? Using current technology, our slowest mode of space transportation, ion drive propulsion, it would take 81,000 years. Using the speeds of one of the fastest spacecraft (Helios 2) and traveling at a constant speed of 240,000 km/hr, it would take about 19,000 years (or over 600 generations) to travel the 4.3 light years.
Artist’s concept shows the New Horizons spacecraft during its 2015 encounter with Pluto and its moon, Charon. Credit: JHUAPL/SwRI
Since the New Horizons spacecraft left Earth back in 2006, there are a few things we know about the Pluto system now that we didn’t know then. For instance, it was discovered Pluto has two additional small moons – P4 and P5 — and Alan Stern, New Horizons Principal Investigator, said Pluto may have a large system of moons to be discovered as the spacecraft gets closer. There are also comets, possibly more dwarf planets and other objects out in the Kuiper Belt region where Pluto orbits.
“That’s exciting,” Stern said, “but this is a mixed story.”
Stern told Universe Today that while the spacecraft possibly could come upon an undiscovered moon or Kuiper Belt Object and they would have to alter course, the biggest issue is tiny debris which may be coming from impacts on the smaller moons.
“We could have 100 moons the size of P4 and they would not be a significant hazard,” Stern said via email. “The hazard is from ejecta coming off these satellites when they are cratered, because the ejecta escapes their feeble gravity and gets into orbit around Pluto.”
At a press conference at the American Astronomical Society’s Division for Planetary Sciences meeting, Stern said that with all the debris in the Kuiper Belt, objects are definitely getting impacted. “If hits occur on Pluto and Charon, they have enough gravity that ejecta just flies across the planet and creates secondary craters. But the ejecta on smaller moons puts shards and debris into the Pluto system.”
Stern said the ejecta speeds from these moons would be comparable to orbital speeds. That means the debris can orbit at any inclination, and there could be a cloud of debris around the system, creating a hazard for the spacecraft.
This worries Stern and his team.
“My spacecraft is going very fast and even a strike from something as small as a BB would be fatal,” he said. “There’s almost no place the spacecraft could get hit and it would be OK.”
Stern said current knowledge of the density of debris of the system can’t prove the spacecraft won’t get hit, and they won’t be able to find out more until they get closer.
“We’re going somewhere new and have no direct evidence of debris that could pose an impact hazard,” he said. “We don’t know what we are going to find and we might have to change our course.”
Stern and his team are looking at some alternative plans, and developing them now is crucial.
“When we plan an encounter for a mission like this, it literally takes tens of thousands of man-hours by experts to put that sequence together and test it,” he said. “We have to plan them now in order to complete that planning. We can’t complete them in the last couple of months or weeks.”
The plans being considered are called SHBOT: Safe Haven Bail Out Trajectory. They currently have nine different possible trajectories, depending on what they find as they get closer.
Screenshot from Stern’s presentation, depicting the nine SHBOT trajectories.
The team is also using every available tool — including sophisticated computer simulations of the stability of debris orbiting Pluto, giant ground-based telescopes, stellar occultation probes of the Pluto system, and even the Hubble Space Telescope — to search for debris in orbit.
Stern told Universe Today that they use the cameras on New Horizons itself every summer when they “wake up” the spacecraft. “LORRI (Long Range Reconnaissance Imager) has already seen Pluto for about 6 years!” he said, “But we won’t pass HST resolution till we’re about 10 weeks out, in April 2015. That’s when we turn on the heavy effort to look for more moons, rings, etc.”
They are looking at the pluses and minuses for each of the plans so they can be tested and be just as “bullet-proof” as the original, nominal flight plan.
In addition to saving the spacecraft, these alternative trajectories also need to preserve the science mission as much as possible. Most of the alternate courses bring the spacecraft farther away from the Pluto system, but one actually brings it closer to Charon, as the path there may be clearer there because of Charon’s gravity and clearing effect.
The spacecraft will start science observations in January 2015, with closest approach to the system currently set for on July 14, 2015 (“Bastille Day,” Stern said, “when we storm the gates of the Pluto system!”)
During the final 50 days of approach, when the spacecraft is taking pictures and sending them back to Earth to be analyzed, the team may discover something and have to fire the spacecraft engines, putting them on one of the SHBOT trajectories. But the last opportunity to actually change course is 10 days before encounter.
“After that we are in too close and we would run out of fuel and not complete the maneuver,” Stern said.
So, while the Mars Science Laboratory team had “Seven minutes of terror” during the perilous landing on Mars, Stern said they have something similar. “We don’t have seven minutes of terror; we have seven weeks of suspense.”
Cassiopeia A in Visible Light Courtesy of the Hubble Space Telescope
Greetings, fellow SkyWatchers! Whoops! (she blushes) I got so lost this weekend in researching Comet ISON that I almost forgot to post the forecast! Ah, well… As they say, better late than never, eh? If you do nothing else this week, be sure to catch the close apparition of Mercury and the “Earthshine Moon” on Wednesday and stay up late Saturday night to watch the Orionid Meteor Shower! In case I forget, just meet me in the back yard…
Monday, October 15 –Today in 1963 marks the first detection of an interstellar molecule. This discovery was made by Sander Weinreb (with Barrett, Meeks, and Henry) on the MIT Millstone Hill 84-foot dish. The discovery was made possible by new correlation receiver technology, and picked up a hydroxyl molecule in an absorption band. By using the radio galaxy Cas A as a background continuum source, the detection occurred at 1667.46 MHz and again at 1665.34 MHz. By the dawn of 2000, nearly 200 different interstellar molecules had been identified and many of these are classified as organic.
Tonight is New Moon! Let’s see what’s up there in the region of Cas A using visible light. The nearest bright star to Cas A is Beta Cassiopeiae – the bright star westward of the “W.” To locate the region of Cas A, go about three finger-widths due west of Beta and follow the subtle curve of three 5th magnitude stars. Cas A lies less than one degree south-southwest of the second star in the sequence of three. This star is a complex 5th magnitude multiple star system associated with variable star AR Cas.
Through binoculars, two stars of the AR system are easily resolved – the 4.9 magnitude primary is seen to be led across the sky by a 7.1 magnitude secondary (component C) which is a very tight double itself. Its 8.9 magnitude partner is resolvable in mid-sized scopes. Large aperture scopes may also be able to distinguish a 9.3 magnitude, second (B) component from the primary. Smaller scopes are back in the running again when attempting three 11th magnitude stars – none of which are close to the primary. Intermediate scopes can also hope to pick out a 12.9 magnitude H component northwest of C. 8.9 magnitude F also has a 9.1 magnitude near twin to the east-northeast. If you can see them all you should probably wrap an observatory building around your telescope – if one isn’t there already!
If you like to follow brightness changes in variables – AR Cas is not a good choice. This eclipsing type variable only fluctuates by a tenth of a magnitude over a period of 6 earth days.
Tuesday, October 16 – Let’s begin our evening by having a look at a radio source as we visit a pulsar located almost mid-way between Theta and Beta Capricorni – PSR2045+16.
While pulsars aren’t truly visible objects, there is still something undeniably cool about locating the field in which a rotating neutron star is sending out staccato pulses of radio waves anywhere between .001 and 4 seconds apart. If you have bright star 19 in the binocular field, then you know you’re in the right area for many radio sources, including many nearby quasars… Just imagine the possibilities!
Now let’s drop south-southeast of Beta Capricorni to have a look at a pair of doubles – Rho and Pi.
Northernmost Pi is a multiple system slightly less than 100 light-years away, with each discernable member also being a spectroscopic double. Separated by about an eighth of a light-year, look for a 5th magnitude yellow/white giant with a very close 9th magnitude companion. Further south is Pi, a triple star system which has a traditional name – Okul. Located around 670 light-years away, look for a bright blue/white 5th magnitude primary that is also a spectroscopic double – and its much easier C component, which is around magnitude 8.
Wednesday, October 17 – For naked-eye observers, enjoy the beautiful “Earthshine” Moon and the close apparition of Mercury!
While you’re out, be sure to gaze upon one of the finest of stars, Vega. Facing West at just after sundown, Vega is bright enough to shine even in the city and will appear just slightly below the zenith. The name Vega means “Falling Eagle” and it is the fifth brightest star in the sky. Enjoyed in either telescopes or binoculars, Vega has a wonderful bluish appearance and a lovely halo of spectra. This magnificent star holds a place in ancient legend and blossomed in our imaginations even more recently as it became the “star” of the movie “Contact”. As the western-most point of the “Southern Triangle”, Vega holds a special appeal for those born in the year 1985. Why? Because Vega is 27 light years away, the light you see from it tonight left the year you were born!
Now point those binoculars towards the northwestern corner of Capricornus and have a look a spectacular Alpha!
Although the Alpha 1 and 2 pairing is strictly a visual binary, that won’t stop you from enjoying their slightly yellow and orange colors. Collectively they are named Al Giedi, and the brighter of the pair is Alpha 2 at about 100 light-years distant; while Alpha 1 is around five times further away. Now power up with a telescope and you’ll find that both stars are also visual doubles! While the companion stars to both are around the same magnitude, you’ll find that Alpha 2 is separated by three times as much distance. Be sure to mark your observation lists and enjoy!
Thursday, October 18 – Today in 1959, Soviet Luna 3 began returning the first photographs of the Moon’s far side. Also today – but in 1967 – the Soviets again made history as Venera 4 became the first spacecraft to probe Venus’ atmosphere.
Have you checked out Mars lately? Mars is now leaving the constellation Scorpius and entering Ophiuchus. At more than 2 AU away from Earth, Mars has become quite dim, and its minimal apparent visual brightness is +1.24 magnitude. Can you still spot a few of its more prominent features?
For a true telescope challenge, we’ll have to go out on a limb – the southeastern lunar limb – to have a look at an unusual crater. Named for the French agrochemist and botanist Jean-Baptiste Boussingault, this elliptical-appearing crater actually spans a handsome 71 kilometers. What makes Boussingault so unusual is that it is home to its own large interior crater – A. This double-ring formation gives it a unique stepped, concentric look that’s worth your time!
When we’re done? Let’s go have a look at Gamma Aquilae just for the heck of it. Just northwest of bright Altair, Gamma has the very cool name of Tarazed and is believed to be over 300 light-years away. This K3 type giant will show just a slightly yellow coloration – but what really makes this one special is the low power field!
Friday, October 19 – Our lunar mission for tonight is a revisit on a crater named for historian and theologian Denis Pétau – Petavius! Located almost centrally along the terminator in the southeast quadrant, a lot will depend tonight on your viewing time and the age the Moon itself. Perhaps when you look, you’ll see 177 kilometer diameter Petavius cut in half by the terminator. If so, this is a great time to take a high magnification look at the small range of mountain peaks contained in its center, as well as a deep rima which runs for 80 kilometers across its otherwise fairly smooth surface. To the east lies a long furrow in the landscape. This deep runnel is Palitzsch and its Valles. While the primary crater which forms this deep gash is only 41 kilometers wide, the valley itself stretches for 110 kilometers. Look for crater Haas on Petavius’ southern edge with Snellius to the southwest and Wrottesley along its northwest wall.
Now, let’s go have a look at the northeastern corner of Capricornus as we learn about Delta…
Its proper name is Deneb Algedi and this nearly 3rd magnitude star is a stunning blue/ white. Curiously enough, it’s a rather close star – only about 50 light-years from Earth. Hovering so close to it that we cannot even correctly assess its spectral type is a binary companion whose eclipsing orbit causes Delta to be a very slight variable – with a period of just about one day. In its own way, Delta is rather historic… For it was only 4 degrees north of this star that Uranus was first sighted by Galle in 1846!
Saturday, October 20 – Tonight, let’s check out a lunar map and go hunting! First let’s start with a look at the Mare Fecunditatus region: (1)Taruntius, (2) Secchi, (3) Messier and Messier A, (4) Lubbock, (5) Guttenberg, (6) Montes Pyrenees, (7) Goclenius, (8) Magelhaens, (9) Columbo, (10) Webb, (11) Langrenus, (12) Lohse, (13) Lame, (14) Vendelinus, (15) the Luna 16 landing site
Mare Fecunditatus Region Photographic Map – Image Credit – Greg Konkel
And here is a closer look at the area around Atlas and Hercules: (1) Mare Humboldtianum, (2) Endymion, (3) Atlas, (4) Hercules, (5) Chevalier, (6) Shuckburgh, (7) Hooke, (8) Cepheus, (9) Franklin, (10) Berzelius, (11) Maury, (12) Lacus Somniorum, (13) Daniel, (14) Grove, (15) Williams, (16) Mason, (17) Plana, (18) Burg, (19) Lacus Mortis, (20) Baily, (21) Atlas E, (22) Keldysh, (23) Mare Frigoris, (24) Democritus, (25) Gartner, (26) Schwabe, (27) Thales, (28) Strabo, (29) de la Rue, (30) Hayn.
Atlas and Hercules Region Photographic Map – Image Credit – Greg Konkel
Have fun marking off lunar challenge craters from your list!
After having looked at the Moon, take the time out to view a bright southern star – Fomalhaut (RA 22 57 39 Dec -29 37 20). Also known as “The Lonely One,” Alpha Piscis Austrini seems to sit in a rather empty area in the southern skies, some 23 light-years away. At magnitude 1, this main sequence A3 giant is the southernmost visible star of its type for northern hemisphere viewers, and is the 18th brightest star in the sky. The Lonely One is about twice the diameter of our own Sun, but 14 times more luminous! Just a little visual aid is all that it takes to reveal its optical companion…
Now we are slipping into the stream of Comet Halley and into one of the finest meteor showers of the year. If skies are clear tonight, this would be the perfect chance to begin your observations of the Orionid meteor shower. But, wait for the Moon to set!
Sunday, October 21 – Be sure to be outdoors before dawn to enjoy one of the year’s most reliable meteor showers. The offspring of Comet Halley will grace the early morning hours as they return once again as the Orionid meteor shower. This dependable shower produces an average of 10-20 meteors per hour at maximum and the best activity begins before local midnight on the 20th, and reaches its best as Orion stands high to the south at about two hours before local dawn on the 21st. With the Moon nearly out of the morning picture, this is gonna’ be great!
Although Comet Halley has long since departed our Solar System, the debris left from its trail still remain scattered in Earth’s orbital path around the Sun, allowing us to predict when this meteor shower will occur. We first enter the “stream” at the beginning of October and do not leave it until the beginning of November, making your chances of “catching a falling star” even greater! These meteors are very fast, and although they are faint, it is still possible to see an occasional fireball that leaves a persistent trail.
For best success, try to get away from city lights. Facing south-southeast, simply relax and enjoy the stars of the winter Milky Way. The radiant, or apparent point of origin, for this shower will be near the red giant Alpha Orionis (Betelguese), but meteors may occur from any point in the sky. You will make your meteor watching experience much more comfortable if you take along a lawn chair, a blanket and a thermos of your favorite beverage.
Clouded out? Don’t despair. You don’t always need your eyes or perfect weather to meteor watch. By tuning an FM radio to the lowest frequency possible that does not receive a clear signal, you can practice radio meteor listening! An outdoor FM antenna pointed at the zenith and connected to your receiver will increase your chances, but it’s not necessary. Simply turn up the static and listen. Those hums, whistles, beeps, bongs, and occasional snatches of signals are our own radio signals being reflected off the meteor’s ion trail! Pretty cool, huh?
