Profile cover photo
Profile photo
Anand Sankar
What makes us human? Our sense of self and our ability to share who we are. Our greatest gift.
What makes us human? Our sense of self and our ability to share who we are. Our greatest gift.

Anand's posts

Post has attachment
Hubble Watches Star Clusters on a Collision Course
Astronomers using data from NASA's Hubble Space Telescope have caught two clusters full of massive stars that may be in the early stages of merging. The 30 Doradus Nebula is 170,000 light-years from Earth. What at first was thought to be only one cluster in the core of the massive star-forming region 30 Doradus has been found to be a composite of two clusters that differ in age by about one million years.
The entire 30 Doradus complex has been an active star-forming region for 25 million years, and it is currently unknown how much longer this region can continue creating new stars. Smaller systems that merge into larger ones could help to explain the origin of some of the largest known star clusters. The Hubble observations, made with the Wide Field Camera 3, were taken Oct. 20-27, 2009. The blue color is light from the hottest, most massive stars; the green from the glow of oxygen; and the red from fluorescing hydrogen.
The Full Story
Astronomers using data from NASA's Hubble Space Telescope have caught two clusters full of massive stars that may be in the early stages of merging. The clusters are 170,000 light-years away in the Large Magellanic Cloud, a small satellite galaxy to our Milky Way.
What at first was thought to be only one cluster in the core of the massive star-forming region 30 Doradus (also known as the Tarantula Nebula) has been found to be a composite of two clusters that differ in age by about one million years.
The entire 30 Doradus complex has been an active star-forming region for 25 million years, and it is currently unknown how much longer this region can continue creating new stars. Smaller systems that merge into larger ones could help to explain the origin of some of the largest known star clusters.
Lead scientist Elena Sabbi of the Space Telescope Science Institute in Baltimore, Md., and her team began looking at the area while searching for runaway stars, fast-moving stars that have been kicked out of their stellar nurseries where they first formed. "Stars are supposed to form in clusters, but there are many young stars outside 30 Doradus that could not have formed where they are; they may have been ejected at very high velocity from 30 Doradus itself," Sabbi said.
She then noticed something unusual about the cluster when looking at the distribution of the low-mass stars detected by Hubble. It is not spherical, as was expected, but has features somewhat similar to the shape of two merging galaxies where their shapes are elongated by the tidal pull of gravity. Hubble's circumstantial evidence for the impending merger comes from seeing an elongated structure in one of the clusters, and from measuring a different age between the two clusters.
According to some models, the giant gas clouds out of which star clusters form may fragment into smaller pieces. Once these small pieces precipitate stars, they might then interact and merge to become a bigger system. This interaction is what Sabbi and her team think they are observing in 30 Doradus.
Also, there is an unusually large number of high-velocity stars around 30 Doradus. Astronomers believe that these stars, often called "runaway stars" were expelled from the core of 30 Doradus as the result of dynamical interactions. These interactions are very common during a process called core collapse, in which more-massive stars sink to the center of a cluster by dynamical interactions with lower-mass stars. When many massive stars have reached the core, the core becomes unstable and these massive stars start ejecting each other from the cluster.
The big cluster R136 in the center of the 30 Doradus region is too young to have already experienced a core collapse. However, since in smaller systems the core collapse is much faster, the large number of runaway stars that has been found in the 30 Doradus region can be better explained if a small cluster has merged into R136.
Follow-up studies will look at the area in more detail and on a larger scale to see if any more clusters might be interacting with the ones observed. In particular the infrared sensitivity of NASA's planned James Webb Space Telescope (JWST) will allow astronomers to look deep into the regions of the Tarantula Nebula that are obscured in visible-light photographs. In these areas cooler and dimmer stars are hidden from view inside cocoons of dust. Webb will better reveal the underlying population of stars in the nebula.
The 30 Doradus Nebula is particularly interesting to astronomers because it is a good example of how star-forming regions in the young universe may have looked. This discovery could help scientists understand the details of cluster formation and how stars formed in the early universe.
The members of Sabbi's team are D.J. Lennon (ESA/STScI), M. Gieles (University of Cambridge, UK), S.E. de Mink (STScI/JHU), N.R. Walborn, J. Anderson, A. Bellini, N. Panagia, and R. van der Marel (STScI), and J. Maíz Apellániz (Instituto de Astrofísica de Andalucía, CISC, Spain)
The Image: 
This is a Hubble Space Telescope image of a pair of star clusters that are believed to be in the early stages of merging. The clusters lie in the gigantic 30 Doradus Nebula, which is 170,000 light-years from Earth.
Hubble's circumstantial evidence for the impending collision comes from seeing an elongated structure in the cluster at upper left, and from measuring a different age between the two clusters. Also, the unusually large number of high-velocity stars around 30 Doradus can finally be explained if a small cluster has merged into the big cluster R136 in the center of the Tarantula Nebula.
This nearby example of cluster interaction yields insights into how star clusters may have formed in the early universe.
The Hubble observations, made with the Wide Field Camera 3, were taken Oct. 20-27, 2009. The blue color is light from the hottest, most massive stars; the green from the glow of oxygen; and the red from fluorescing hydrogen.
Release Date: Aug 16, 2012
Credit: NASA, ESA, and E. Sabbi (ESA/STScI)
Acknowledgment: R. O'Connell (University of Virginia) and the Wide Field Camera 3 Science Oversight Committee
 #nasa #esa #spaceexploration

Post has attachment
After the historic Apollo Missions, which saw humans set foot on another celestial body for the first time in history, NASA and the Russian Space Agency (Roscosmos) began to shift their priorities away from pioneering space exploration and began to focus on developing long-term capabilities in space. In the ensuing decades (from the 1970s to 1990s), both agencies began to build and deploy space stations, each one bigger and more complex than the last.
The latest and greatest of these is the International Space Station (ISS), a scientific facility that resides in Low-Earth Orbit around our planet. This space station is the largest and most sophisticated orbiting research facility ever built, and is so large that it can actually be seen with the naked eye. Central to its mission is the idea of fostering international cooperation for the sake of advancing science and space exploration.
Planning for the ISS began in the 1980s and was based in part on the successes of Russia’s Mir space station, NASA’s Skylab, and the Space Shuttle Program. This station, it was hoped, would allow for the future utilization of  low-Earth Orbit and its resources, and serve as an intermediate base for renewed exploration efforts to the Moon, mission to Mars, and beyond.
In May of 1982, NASA established the Space Station task force, which was charged with created a conceptual framework for such a space station. In the end, the ISS plan that emerged was a culmination of several different plans for a space station – which included NASA’s Freedom and the Soviet’s Mir-2 concepts, as well as Japan’s Kibolaboratory, and the European Space Agency’s Columbus laboratory.
The Freedom concept called for a modular space station to be deployed to orbit, where it would serve as the counterpart to the Soviet Salyut and Mir space stations. That same year, NASA approached the Japanese Aerospace and Exploration Agency (JAXA) to participate in the program with the creation of the Kibo, also known as the Japanese Experiment Module.
The Canadian Space Agency was similarly approached in 1982 and was asked to provide robotic support for the station. Thanks to the success of the Canadarm, which was an integral part of the Space Shuttle Program, the CSA agreed to develop robotic components that would assist with docking, perform maintenance, and assist astronauts with spacewalks.
In 1984, the ESA was invited to participate in the construction of the station with the creation of the Columbus laboratory – a research and experimental lab specializing in materials science. Construction of both Kibo and Columbus were approved of in 1985. As the most ambitious space program in either agency’s history, the development of these laboratories was seen as central to Europe and Japan’s emerging space capability.
In 1993, American Vice-President Al Gore and Russian Prime Minister Viktor Chernomyrdin announced that they would be pooling the resources intended to create Freedom and Mir-2. Instead of two separate space stations, the programs would be working collaboratively to create a single space station – which was later named the International Space Station.
Construction of the ISS was made possible with the support of multiple federal space agencies, which included NASA, Roscosmos, JAXA, the CSA, and members of the ESA – specifically Belgium, Denmark, France, Spain, Italy, Germany, the Netherlands, Norway, Switzerland, and Sweden. The Brazilian Space Agency (AEB) also contributed to the construction effort.
The orbital construction of the space station began in 1998 after the participating nations signed the Space Station Intergovernmental Agreement (IGA), which established a legal framework that stressed cooperation based on international law. The participating space agencies also signed the Four Memoranda of Understandings (MoUs), which laid out their responsibilities in the design, development and use of the station.
The assembly process began in 1998 with the deployment of the ‘Zarya’ (“Sunrise” in Russian) Control Module, or Functional Cargo Block. Built by the Russians with funding from the US, this module was designed to provide the station’s initial propulsion and power. The pressurized module – which weighed over 19,3oo kg (42,600 pounds) – was launched aboard a Russian Proton rocket in November 1998.
On Dec. 4th, the second component – the ‘Unity’ Node – was placed into orbit by the Space Shuttle Endeavour (STS-88), along with two pressurized mating adapters. This node was one of three – Harmony and Tranquility being the other two – that would form the ISS’ main hull. On Sunday, Dec. 6th, it was mated to Zarya by the STS-88 crew inside the shuttle’s payload bay.
The next installments came in the year 2000, with the deployment of the ZvezdaService Module (the first habitation module) and multiple supply missions conducted by the Space Shuttle Atlantis.  The Space Shuttle Discovery (STS-92) also delivered the stations third pressurized mating adapted and a Ku-band antenna in October. By the end of the month, the first Expedition crew was launched aboard a Soyuz rocket, which arrived on Nov. 2nd.
In 2001, the ‘Destiny’ Laboratory Module and the ‘Pirs’ Docking Compartment were delivered. The modular racks that are part of Destiny were also shipped using the Raffaello Multi-Purpose Logistic Modules (MPLM) aboard the Space Shuttle Endeavour, and put into place using the Canadarm2 robotic arm. 2002 saw additional racks, truss segments, solar arrays, and the Mobile Base System for the Station’s Mobile Servicing System being delivered.
In 2007, the European Harmony module was installed, which allowed for the addition of the Columbus and Kibo laboratories – both of which were added in 2008. Between 2009 and 2011, construction was finalized with the addition of the Russian Mini-Research Module-1 and -2 (MRM1 and MRM2), the ‘Tranquility’ Node, the Cupola Observation Module, the Leonardo Permanent Multipurpose Module, and the Robonaut 2 technology suite.
No additional modules or components were added until 2016, when Bigelow Aersopace installed their experimental Bigelow Expandable Activity Module (BEAM). All told, it took 13 years to construct the space station, an estimated $100 billion, and required more than 100 rocket and Space Shuttle launches, and 160 spacewalks.
As of the penning of this article, the station has been continuously occupied for a period of 16 years and 74 days since the arrival of Expedition 1 on November 2nd, 2000. This is the longest continuous human presence in low Earth orbit, having surpassed Mir’s record of 9 years and 357 days.
Purpose and Aims:
The main purpose of the ISS is fourfold: conducting scientific research, furthering space exploration, facilitating education and outreach, and fostering international cooperation. These goals are backed by NASA, the Russian Federal Space Agency (Roscomos), the Japanese Aerospace Exploration Agency (JAXA), the Canadian Space Agency (CSA), and the European Space Agency (ESA), with additional support from other nations and institutions.
As far as scientific research goes, the ISS provides a unique environment to conduct experiments under microgravity conditions. Whereas crewed spacecraft provide a limited platform that is only deployed to space for a limited amount of time, the ISS allows for long-term studies that can last for years (or even decades).
Many different and continuous projects are being conducted aboard the ISS, which are made possible with the support of a full-time crew of six astronauts, and a continuity of visiting vehicles (which also allows for resupply and crew rotations). Scientists on Earth have access to their data, and are able to communicate with the science teams through a number of channels.
The many fields of research conducted aboard the ISS include astrobiology, astronomy, human research, life sciences, physical sciences, space weather, and meteorology. In the case of space weather and meteorology, the ISS is in a unique position to study these phenomena because it’s position in LEO. Here, it has a short orbital period, allowing it to witness weather across the entire globe many times in a single day.
It is also exposed to things like cosmic rays, solar wind, charged subatomic particles, and other phenomena that characterize a space environment. Medical research aboard the ISS is largely focused on the long-term effects of microgravity on living organisms – particularly its effects on bone density, muscle degeneration and organ function – which is intrinsic to long-range space exploration missions.
The ISS also conducts research that is beneficial to space exploration systems. It’s location in LEO also allows for the testing of spacecraft systems that are required for long-range missions. It also provides an environment where astronauts can gain vital experience in terms of operations, maintenance and repair services – which are similarly crucial for long-term missions (such as mission to the Moon and Mars).
The ISS also provides opportunities for education thanks to participation in experiments, where students are able to design experiments and watch as ISS crews carry them out. ISS astronauts are also able to engage classrooms through video link, radio communications, email, and educational videos/web episodes. Various space agencies also maintain educational materials for download based on ISS experiments and operations.
Educational and cultural outreach also fall within the ISS’ mandate. These activities are conducted with the help and support of the participating federal space agencies, and which are designed to encourage education and career training in the STEM (Science, Technical, Engineering, Math) fields.
One of the best known examples of this are the educational videos created by Chris Hadfield – the Canadian astronaut who served as the commander of Expedition 35 aboard the ISS – which chronicled the everyday activities of ISS astronauts. He also directed a great deal of attention to ISS activities thanks to his musical collaboration with the Barenaked Ladies and Wexford Gleeks – titled “I.S.S. (Is Somebody Singing)” (shown above).
His video, a cover of David Bowie’s “Space Oddity”, also earned him widespread acclaim. Along with drawing additional attention to the ISS and its crew operations, it was also a major feat since it was the only music video ever to be filmed in space!
The Image: 
*The International Space Station orbiting Earth. *
Credit: NASA
Read Full Article :
Article By: Matt Williams
Updated: 12 Jan , 2017
Image Source:
#nasa #esa #spaceexploration

Post has attachment
Four ALMA antennas on the Chajnantor plain
Four of the first ALMA antennas at the Array Operations Site (AOS), located at 5000 metres altitude on the Chajnantor plateau, in the II Region of Chile. Three of them — those which are pointing in the same direction — are being tested together as part of the ongoing Commissioning and Science Verification process. Across the image in the background is the impressive plane of the Milky Way, our own galaxy, here seen looking toward the centre. The centre of our galaxy is visible as a yellowish bulge crossed by dark lanes. The dark lanes are huge clouds of interstellar dust that lie in the disc of the galaxy. While opaque in visible light, they are transparent at longer wavelengths, such as the millimetre and submillimetre radiation detected by ALMA. ALMA, the Atacama Large Millimeter/submillimeter Array, is the largest astronomical project in existence and is a truly global partnership between the scientific communities of East Asia, Europe and North America with Chile. ESO is the European partner in ALMA.
Credit:ESO/José Francisco Salgado (
#nasa #esa #spaceexploration

Post has attachment
Peacocks are large, colorful pheasants (typically blue and green) known for their iridescent tails. These tail feathers, or coverts, spread out in a distinctive train that is more than 60 percent of the bird’s total body length and boast colorful "eye" markings of blue, gold, red, and other hues. The large train is used in mating rituals and courtship displays. It can be arched into a magnificent fan that reaches across the bird's back and touches the ground on either side. Females are believed to choose their mates according to the size, color, and quality of these outrageous feather trains.
Male vs. Female
The term "peacock" is commonly used to refer to birds of both sexes. Technically, only males are peacocks. Females are peahens, and together, they are called peafowl.
Suitable males may gather harems of several females, each of which will lay three to five eggs. In fact, wild peafowl often roost in forest trees and gather in groups called parties.
Peacocks are ground-feeders that eat insects, plants, and small creatures. There are two familiar peacock species. The blue peacock lives in India and Sri Lanka, while the green peacock is found in Java and Myanmar (Burma). A more distinct and little-known species, the Congo peacock, inhabits African rain forests.
Peafowl such as the blue peacock have been admired by humans and kept as pets for thousands of years. Selective breeding has created some unusual color combinations, but wild birds are themselves bursting with vibrant hues. They can be testy and do not mix well with other domestic birds.
Data Source:
Image Source:
#peacocks #peafowl #indianpeacock

Post has attachment
Ancient Stardust Sheds Light on the First Stars
Most distant object ever observed by ALMA
Astronomers have used ALMA to detect a huge mass of glowing stardust in a galaxy seen when the Universe was only four percent of its present age. This galaxy was observed shortly after its formation and is the most distant galaxy in which dust has been detected. This observation is also the most distant detection of oxygen in the Universe. These new results provide brand-new insights into the birth and explosive deaths of the very first stars.
An international team of astronomers, led by Nicolas Laporte of University College London, have used the Atacama Large Millimeter/submillimeter Array (ALMA) to observe A2744_YD4, the youngest and most remote galaxy ever seen by ALMA. They were surprised to find that this youthful galaxy contained an abundance of interstellar dust — dust formed by the deaths of an earlier generation of stars.
Follow-up observations using the X-shooter instrument on ESO’s Very Large Telescope confirmed the enormous distance to A2744_YD4. The galaxy appears to us as it was when the Universe was only 600 million years old, during the period when the first stars and galaxies were forming [1].
“Not only is A2744_YD4 the most distant galaxy yet observed by ALMA,” comments Nicolas Laporte, “but the detection of so much dust indicates early supernovae must have already polluted this galaxy.”
Cosmic dust is mainly composed of silicon, carbon and aluminium, in grains as small as a millionth of a centimetre across. The chemical elements in these grains are forged inside stars and are scattered across the cosmos when the stars die, most spectacularly in supernova explosions, the final fate of short-lived, massive stars. Today, this dust is plentiful and is a key building block in the formation of stars, planets and complex molecules; but in the early Universe — before the first generations of stars died out — it was scarce.
The observations of the dusty galaxy A2744_YD4 were made possible because this galaxy lies behind a massive galaxy cluster called Abell 2744 [2]. Because of a phenomenon called gravitational lensing, the cluster acted like a giant cosmic “telescope” to magnify the more distant A2744_YD4 by about 1.8 times, allowing the team to peer far back into the early Universe.
The ALMA observations also detected the glowing emission of ionised oxygen from A2744_YD4. This is the most distant, and hence earliest, detection of oxygen in the Universe, surpassing another ALMA result from 2016.
The detection of dust in the early Universe provides new information on when the first supernovae exploded and hence the time when the first hot stars bathed the Universe in light. Determining the timing of this “cosmic dawn” is one of the holy grails of modern astronomy, and it can be indirectly probed through the study of early interstellar dust.
The team estimates that A2744_YD4 contained an amount of dust equivalent to 6 million times the mass of our Sun, while the galaxy’s total stellar mass — the mass of all its stars — was 2 billion times the mass of our Sun. The team also measured the rate of star formation in A2744_YD4 and found that stars are forming at a rate of 20 solar masses per year — compared to just one solar mass per year in the Milky Way [3].
“This rate is not unusual for such a distant galaxy, but it does shed light on how quickly the dust in A2744_YD4 formed,” explains Richard Ellis (ESO and University College London), a co-author of the study. “Remarkably, the required time is only about 200 million years — so we are witnessing this galaxy shortly after its formation.”
This means that significant star formation began approximately 200 million years before the epoch at which the galaxy is being observed. This provides a great opportunity for ALMA to help study the era when the first stars and galaxies “switched on” — the earliest epoch yet probed. Our Sun, our planet and our existence are the products — 13 billion years later — of this first generation of stars. By studying their formation, lives and deaths, we are exploring our origins.
“With ALMA, the prospects for performing deeper and more extensive observations of similar galaxies at these early times are very promising,” says Ellis.
And Laporte concludes: “Further measurements of this kind offer the exciting prospect of tracing early star formation and the creation of the heavier chemical elements even further back into the early Universe.”
[1] This time corresponds to a redshift of z=8.38, during the epoch of reionisation.
[2] Abell 2744 is a massive object, lying 3.5 billion light-years away (redshift 0.308), that is thought to be the result of four smaller galaxy clusters colliding. It has been nicknamed Pandora’s Cluster because of the many strange and different phenomena that were unleashed by the huge collision that occurred over a period of about 350 million years. The galaxies only make up five percent of the cluster’s mass, while dark matter makes up seventy-five percent, providing the massive gravitational influence necessary to bend and magnify the light of background galaxies. The remaining twenty percent of the total mass is thought to be in the form of hot gas.
[3] This rate means that the total mass of the stars formed every year is equivalent to 20 times the mass of the Sun.
More information
This research was presented in a paper entitled “Dust in the Reionization Era: ALMA Observations of a z =8.38 Gravitationally-Lensed Galaxy” by Laporte et al., to appear in The Astrophysical Journal Letters.
The team is composed of N. Laporte (University College London, UK), R. S. Ellis (University College London, UK; ESO, Garching, Germany), F. Boone (Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France), F. E. Bauer (Pontificia Universidad Católica de Chile, Instituto de Astrofísica, Santiago, Chile), D. Quénard (Queen Mary University of London, London, UK), G. Roberts-Borsani (University College London, UK), R. Pelló (Institut de Recherche en Astrophysique et Planétologie (IRAP), Toulouse, France), I. Pérez-Fournon (Instituto de Astrofísica de Canarias, Tenerife, Spain; Universidad de La Laguna, Tenerife, Spain), and A. Streblyanska (Instituto de Astrofísica de Canarias, Tenerife, Spain; Universidad de La Laguna, Tenerife, Spain).
The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of ESO, the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).
ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.
ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.
The Image
Artist’s impression of the remote dusty galaxy A2744_YD4
This artist’s impression shows what the very distant young galaxy A2744_YD4 might look like. Observations using ALMA have shown that this galaxy, seen when the Universe was just 4% of its current age, is rich in dust. Such dust was produced by an earlier generation of stars and these observations provide insights into the birth and explosive deaths of the very first stars in the Universe.
Credit:ESO/M. Kornmesser
 #nasa #esa #spaceexploration

Post has attachment
Led Zeppelin - Whole Lotta Love

You need coolin', baby, I'm not foolin',
I'm gonna send you back to schoolin',
Way down inside honey, you need it,
I'm gonna give you my love,
I'm gonna give you my love.

#ledzeppelin #throwbackthursday #tbt 

Post has attachment
Microlensing Study Suggests Most Common Outer Planets Likely Neptune-mass
A new statistical study of planets found by a technique called gravitational microlensing suggests that Neptune-mass worlds are likely the most common type of planet to form in the icy outer realms of planetary systems. The study provides the first indication of the types of planets waiting to be found far from a host star, where scientists suspect planets form most efficiently. 
"We've found the apparent sweet spot in the sizes of cold planets. Contrary to some theoretical predictions, we infer from current detections that the most numerous have masses similar to Neptune, and there doesn't seem to be the expected increase in number at lower masses," said lead scientist Daisuke Suzuki, a post-doctoral researcher at NASA's Goddard Space Flight Center in Greenbelt, Maryland, and the University of Maryland Baltimore County. "We conclude that Neptune-mass planets in these outer orbits are about 10 times more common than Jupiter-mass planets in Jupiter-like orbits."
 Gravitational microlensing takes advantage of the light-bending effects of massive objects predicted by Einstein's general theory of relativity. It occurs when a foreground star, the lens, randomly aligns with a distant background star, the source, as seen from Earth. As the lensing star drifts along in its orbit around the galaxy, the alignment shifts over days to weeks, changing the apparent brightness of the source. The precise pattern of these changes provides astronomers with clues about the nature of the lensing star, including any planets it may host.
"We mainly determine the mass ratio of the planet to the host star and their separation," said team member David Bennett, an astrophysicist at Goddard. "For about 40 percent of microlensing planets, we can determine the mass of the host star and therefore the mass of the planet."
More than 50 exoplanets have been discovered using microlensing compared to thousands detected by other techniques, such as detecting the motion or dimming of a host star caused by the presence of planets. Because the necessary alignments between stars are rare and occur randomly, astronomers must monitor millions of stars for the tell-tale brightness changes that signal a microlensing event.
However, microlensing holds great potential. It can detect planets hundreds of times more distant than most other methods, allowing astronomers to investigate a broad swath of our Milky Way galaxy. The technique can locate exoplanets at smaller masses and greater distances from their host stars, and it's sensitive enough to find planets floating through the galaxy on their own, unbound to stars.
NASA's Kepler and K2 missions have been extraordinarily successful in finding planets that dim their host stars, with more than 2,500 confirmed discoveries to date. This technique is sensitive to close-in planets but not more distant ones. Microlensing surveys are complementary, best probing the outer parts of planetary systems with less sensitivity to planets closer to their stars.
"Combining microlensing with other techniques provides us with a clearer overall picture of the planetary content of our galaxy," said team member Takahiro Sumi at Osaka University in Japan.
From 2007 to 2012, the Microlensing Observations in Astrophysics (MOA) group, a collaboration between researchers in Japan and New Zealand, issued 3,300 alerts informing the astronomical community about ongoing microlensing events. Suzuki's team identified 1,474 well-observed microlensing events, with 22 displaying clear planetary signals. This includes four planets that were never previously reported.
To study these events in greater detail, the team included data from the other major microlensing project operating over the same period, the Optical Gravitational Lensing Experiment (OGLE), as well as additional observations from other projects designed to follow up on MOA and OGLE alerts.
From this information, the researchers determined the frequency of planets compared to the mass ratio of the planet and star as well as the distances between them. For a typical planet-hosting star with about 60 percent the sun's mass, the typical microlensing planet is a world between 10 and 40 times Earth's mass. For comparison, Neptune in our own solar system has the equivalent mass of 17 Earths.
The results imply that cold Neptune-mass worlds are likely to be the most common types of planets beyond the so-called snow line, the point where water remained frozen during planetary formation. In the solar system, the snow line is thought to have been located at about 2.7 times Earth's mean distance from the sun, placing it in the middle of the main asteroid belt today.
A paper detailing the findings was published in The Astrophysical Journal on Dec. 13.
"Beyond the snow line, materials that were gaseous closer to the star condense into solid bodies, increasing the amount of material available to start the planet-building process," said Suzuki. "This is where we think planetary formation was most efficient, and it's also the region where microlensing is most sensitive."
NASA's Wide Field Infrared Survey Telescope (WFIRST), slated to launch in the mid-2020s, will conduct an extensive microlensing survey. Astronomers expect it will deliver mass and distance determinations of thousands of planets, completing the work begun by Kepler and providing the first galactic census of planetary properties.
NASA's Ames Research Center manages the Kepler and K2 missions for NASA's Science Mission Directorate. The Jet Propulsion Laboratory (JPL) in Pasadena, California, managed Kepler mission development. Ball Aerospace & Technologies Corporation operates the flight system with support from the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.
WFIRST is managed at Goddard, with participation by JPL, the Space Telescope Science Institute in Baltimore, the Infrared Processing and Analysis Center, also in Pasadena, and a science team comprising members from U.S. research institutions across the country.
 For more information on how NASA’s Kepler is working with ground-based efforts, including the MOA and OGLE groups, to search for planets using microlensing, please visit:  
By Francis Reddy
NASA's Goddard Space Flight Center in Greenbelt, Maryland
The Image: 
Neptune-mass exoplanets like the one shown in this artist's rendering may be the most common in the icy regions of planetary systems. Beyond a certain distance from a young star, water and other substances remain frozen, leading to an abundant population of icy objects that can collide and form the cores of new planets. In the foreground, an icy body left over from this period drifts past the planet.
Credits: NASA/Goddard/Francis Reddy
#nasa #esa #spaceexploration

Post has attachment
Dashavatara of Lord Vishnu
Part 4 of 10
Narasimha (Sanskrit: meaning "man-lion")
In the Hindu religion, Narasimha (Sanskrit: meaning "man-lion") is the fourth avatar of Vishnu, the preserver god in the Hindu Trimurti (trinity), who appeared in ancient times to save the world from an arrogant demon figure. According to Hindu mythology, Narasimha's half-lion, half-man appearance allowed him to circumvent the boon received by the demon king Hiranyakashipu that he could not be killed by any human or animal. Since Narasimha was neither fully animal nor fully human, he was able to slay the demon and save the world.
Hinduism teaches that whenever humanity is threatened by extreme social disorder and wickedness, God will descend into the world as an avatar to restore righteousness, establish cosmic order, and redeem humanity from danger. The avatar doctrine presents a view of divinity that is compatible with evolutionary thinking since it suggests a gradual progression of avatars from amphipian through mammal to later human and godly forms. Most importantly, the concept of avatar presents the theological view of a deeply personal and loving God who cares about the fate of humanity rather than ignores it. Time and time again, the various avatars are willing to intervene on humanity's behalf to protect its overall cosmic wellbeing (loka-samgraha).
Narasimha in the Context of the Avatar Doctrine
The avatar doctrine is a seminal concept in certain forms of Hinduism, particularly Vaishnavism, the sect that worships Vishnu as the Supreme God. The word Avatar in Sanskrit literally means "descent" of the divine into the realm of material existence. Through the power of maya ("illusion" or "magic"), it is said that God can manipulate forms in the physical realm, and is therefore able to assume bodily forms and become immanent in the empirical world. Hinduism states that the Absolute can take on innumerable forms and, therefore, the number of avatars is theoretically limitless. However, in practice, the term Avatar is most ubiquitously related to Lord Vishnu, of whom Narasimha is an incarnation.
Hinduism recognizes ten major avatars, collectively known as the 'Dasavatara' ('dasa' in Sanskrit means ten). Scriptural lists of these ten divine manifestations frequently differ, however, the most commonly accepted has Narasimha preceded by Matsya, a fish; Kurma, a turtle; and Varaha, a boar; and followed by Vamana, a dwarf; Parasurama, Rama with an axe; Rama, a noble man; Krishna, the teacher of the Bhagavadgita; Buddha,[1] a spiritually enlightened being, and Kalkin, the final avatar who has yet to arrive. These avatars usually take physical form for the purpose of protecting or restoring dharma, the cosmic principle of order, when it has devolved. Krishna explains this in the Bhagavadgita: "Whenever there is a decline of righteousness and rise of unrighteousness O Arjuna, I send forth Myself." (Shloka 4.7) Vishnu's tenure on earth typically involves the performance of a particular series of events in order to instruct others concerning the path of bhakti (devotion) and ultimately leading them to moksha (liberation).
In Hindu mythology, Narasimha is the avatar who battled the demon Hiranyakashipu. Due to the devotion of Hiranyakashipu's parents to Brahma, they gave birth to a son named Hiranyakashipu, who was predicted would become very powerful. Having propitiated Lord Brahma himself, Hiranyakashipu received a boon from the creator god that made him invulnerable to three things: gods, humans and beasts. Brahma decreed that he could neither be slain in the day or night, nor inside or outside. With these divine promises in place, Hiranyakashipu began to consider himself god in the flesh and forbade worship of all the gods. His son Prahlada, however, was a faithful devotee of Vishnu and did not give up his worship of Vishnu despite the threats and tortures visited upon him. Enraged, Hiranyakashipu attempted to kill his son by a variety of means: drowning, tossing him off a cliff, caging him with poisonous snakes, feeding him to lions, having him trampled by elephants and burning him alive. However, the son esacped each of these ordeals unharmed. Discontent with his failures, Hiranyakashipu attempted to shatter the boy's love for Vishnu; the child, however, kept singing the god's praises no matter how hard Hiranyakashipu tried to break his spirits. One night at dusk, Hiranyakashipu finally asked his son as to the location of Vishnu, to which his son replied "everywhere." Angered, Hiranyakashipu struck the pillar in the entrance of his palace and asked if Vishnu was in there, too. The child answered in the affirmative and so Hiranyakashipu continued to kick the pillar. The pillar shook and then shattered, and from it emerged Narasimha, who took the demon king on his lap and then eviscerated him with his claws. Since Narasimha was 1) neither man nor beast in his nature, 2) present in the twilight, and 3) because the pillar in which he appeared was neither inside or outside the house, he fulfilled all the criteria enabling him to defeat Hiranyakashipu.
A Shaivic account[2] of this story claims that after emancipating the world from the harmful rule of Hiranyakashipu, Narasimha grew conceited with his victory. In order to put him in check, Shiva took the form of Sharabha, a mythical creature which is half-bird and half-lion. Sharabha tore up as Narasimha, much Narasimhna had torn up Hiranyakashipu, then wore the man-lion's skin as a garment. The face of the Narasimha, meanwhile, was thereafter used as an ornamentation upon Shiva's chest.
While avatars preceding Narasimha were depicted as half-human, half-animal to symbolically assert their nature as both animal and avatars of Vishnu, Narasimha is pictured this way in order to display his actual physiognomy. The main emphasis of his depictions is often placed upon his power, braveness and independence. In some depictions he is ferocious, with three large bulging eyes, a gaping mouth with fangs bared, his mane heavy, his tail flayed upon the ground, and his sharp claws withdrawn. In other depictions he is more calm, seated or standing peacefully amongst his consorts and showing yogic signs. Often, his legs are crossed in the lotus position, held there by a meditation band (or yoga-patta), as if he is engaged in deep contemplation. These kind of depictions are classified as Yoga-Narasimha. Sometimes he is pictured with consorts, such as Lakshmi. In his more vicious forms he is shown carrying the slain Hiranyakashipu on his lap. His color is usually bright yellow. He is most commonly pictured with four arms, but can also have two, eight or as many as sixteen arms. He carries a variety of weapons and symbols associated with Vishnu such as the club (a symbol of knowledge), a wheel, a conch, a discus and an axe depending on the number of arms depicted. One free hand is often held in the abhaya mudra, a symbol of fearlessness. Behind his head there often rises a seven-headed serpent, representing the cosmic snake Shesha upon which he is said to sleep.
Narasimha represents the acknowledgement on the part of Hinduism that human beings and animals are closely related in the sphere of creation. Among all the creatures, humans are considered to be the best by Hindus, and among all the animals, the lion is held to be the highest. With their combined intelligence and ferocity, they are seen to be a very powerful entity in the phenomenal world. The intelligent way in which Narasimha overcame the boon of invincibility possessed by Hiranyakashipu, and the ferocity with which he killed the demon illustrate his ability to combine the intellect of a human being with the fierocity of animal instinct. At the threshold between the most superior beast and human being, Narasimha illustrates the symbiosis between human beings and animals upon the continuum of creation.
In addition, Narasimha has taken on a significant religious following in comparison to some of the other early avatars. Numerous pilgrimage sites and temples have been dedicated to him throughout India, particularly in the state of Andrah Pradesh, India, where there are seven pilgrimage sites to Narasimha still standing. Narasimha is also a key figure within the popular Holi festival (the festival of colors), during which aspects of his myth are reenacted. Partly due to Narasimha's often ferocious nature, worshippers are very meticulous when worshipping his images, fearing any display of carelessness will incur his wrath.
* ↑ Note: some Hindu sources replace the Buddha with Balarama.
* ↑ Shiva Purana. (India: Dreamland Publications, April 1, 2007. ISBN 8173017042)
* Bassuk, Daniel E. Incarnation in Hinduism and Christianity: the myth of the god-man. Atlantic Highlands, NJ: Humanities Press International, 1987. ISBN 0391034529
* Gupta, Shakti. Vishnu and His Incarnations. Delhi: Somaiya Publications Pvt. Ltd., 1974.
* Mitchell, A. G. Hindu Gods and Goddesses. London: Her Majesty's Stationery Office, 1982. ISBN 011290372X
* Parrinder, Geoffrey. Avatar and incarnation: the Wilde lectures in natural and comparative religion in the University of Oxford. London: Faber, 1970. ISBN 0571093191
* Soifer, Deborah A. The Myths of Narasimha and Vamana: Two Avatars in Cosmological Perspective. NY: State University of New York Press, 1991. ISBN 9780791408001
This article began as an original work prepared for New World Encyclopedia and is provided to the public according to the terms of the New World Encyclopedia:Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Any changes made to the original text since then create a derivative work which is also CC-by-sa licensed. To cite this article click here for a list of acceptable citing formats.
Note: Some restrictions may apply to use of individual images which are separately licensed.
#Vishnu #Krishna #dashavatar #narasimha

Post has attachment
Spitzer Hears Stellar 'Heartbeat' from Planetary Companion
A planet and a star are having a tumultuous romance that can be detected from 370 light-years away.
NASA's Spitzer Space Telescope has detected unusual pulsations in the outer shell of a star called HAT-P-2. Scientists' best guess is that a closely orbiting planet, called HAT-P-2b, causes these vibrations each time it gets close to the star in its orbit.
"Just in time for Valentine's Day, we have discovered the first example of a planet that seems to be causing a heartbeat-like behavior in its host star," said Julien de Wit, postdoctoral associate at the Massachusetts Institute of Technology, Cambridge. A study describing the findings was published today in Astrophysical Journal Letters.
 The star's pulsations are the most subtle variations of light from any source that Spitzer has ever measured. A similar effect had been observed in binary systems called "heartbeat stars" in the past, but never before between a star and a planet.
 Weighing in at about eight times the mass of Jupiter, HAT-P-2b is a relatively massive planet. It's a "hot Jupiter," meaning an exoplanet that is extremely warm and orbits its star tightly. But this hot Jupiter is tiny in relation to its host star, which is about 100 times more massive. That size difference makes the pulsation effect all the more unusual (For comparison, our sun is about 1,000 times more massive than Jupiter).
"It's remarkable that this relatively small planet seems to affect the whole star in a way that we can see from far away," said Heather Knutson, assistant professor of geological and planetary sciences at Caltech in Pasadena, California.
Known to the exoplanet community since 2007, HAT-P-2b was initially interesting to astronomers because of its "eccentric," or elliptical orbit. The planet spends most of its time relatively far from the star, but comes around for a close encounter every 5.6 days. Those are indeed hot dates for this planet, as it receives as much as 10 times the amount of light per unit area at closest approach than at its farthest point in the orbit.
 Each time the planet swings around for that close approach, it appears to gives its star a little "kiss" as the gravitational forces of these two bodies interact. The star, in turn, beats like a heart as the planet travels around in its orbit again. For a less lovey-dovey analogy: The planet's gravity hits the star like a bell on closest approach, making it ring throughout the planet's orbit.  
 "We had intended the observations to provide a detailed look at HAT-P-2b’s atmospheric circulation," said Nikole Lewis, co-author and astronomer at Space Telescope Science Institute, Baltimore. "The discovery of the oscillations was unexpected but adds another piece to the puzzle of how this system evolved."
 Spitzer watched the planet-star interactions from the vantage point of our own solar system, in the telescope's Earth-trailing orbit around the sun, for about 350 hours between July 2011 and November 2015. Because of the system's alignment with respect to Earth, Spitzer was able to observe the planet cross directly in front of the star (in a process called a "transit") as well as behind it (called a "secondary eclipse"). These eclipses of the planet allowed scientists to determine that the pulsations originate from the star, not the planet. The point of closest approach occurs between the transit and secondary eclipse. 
The planetary system still has scientists stumped. Calculations by co-author Jim Fuller, Caltech postdoctoral scholar, predicted that the pitter-patter of the star's vibrations should be quieter and at a lower frequency than what Spitzer found.
"Our observations suggest that our understanding of planet-star interactions is incomplete," said de Wit. "There's more to learn from studying stars in systems like this one and listening for the stories they tell through their 'heartbeats.'"
JPL manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit:  
Elizabeth Landau
>Jet Propulsion Laboratory, Pasadena, Calif.
The Image: 
This illustration shows how the planet HAT-P-2b, left, appears to cause heartbeat-like pulsations in its host star, HAT-P-2.
Credits: NASA/JPL-Caltech
#nasa #esa #spaceexploration

Post has attachment
SpaceX Mission Poised for Notable Achievements
NASA's first cargo resupply mission of 2017 is poised to lift off from Kennedy Space Center in Florida loaded with almost 5,500 pounds of science experiments, research equipment and supplies bound for the International Space Station and its resident astronauts.
The gear is packed into a SpaceX Dragon capsule that will fly into orbit aboard the company's Falcon 9 rocket. It will take two days for the Dragon to catch up to the space station and move within reach of the station's 57-foot-long robotic arm.
Astronauts Shane Kimbrough of NASA and Thomas Pesquet of the European Space Agency will use the arm to capture Dragon and maneuver it to its berthing port on the station. The uncrewed Dragon is pressurized so astronauts aboard the orbiting laboratory can unpack the cargo and later fill it up with completed experiments and used equipment for return to Earth.
This cargo mission by SpaceX also will set a milestone as the first launch from Launch Complex 39A since the space shuttle fleet retired in 2011. It will mark a turning point for Kennedy's transition to a multi-user spaceport geared to support public and private missions, as well as those conducted in partnership with NASA.
Some of humanity's greatest adventures in orbit began at Launch Complex 39A. Astronauts lifted off from this pad six times between 1969 and 1972 to walk upon lunar soil. Flying inside Apollo spacecraft atop massive Saturn V rockets, the astronauts left Florida and the Earth behind for two weeks, while they ventured to the moon.
In 1981, it began hosting the world's first reusable spacecraft, NASA's space shuttles, on missions that would make working in space more accessible, while still achieving breathtaking science and accomplishing engineering feats that would have been out of reach before.
Some of the first pieces of the International Space Station began their operational lives with fiery liftoffs from the site including NASA's first station construction mission, STS-88 in 1998.
Although the majority of the supplies and experiments will be used inside the station, one of the major payloads of SpaceX’s CRS-10 mission will be attached to the outside of the station to survey aspects of Earth's atmosphere. The SAGE III project, short for Stratospheric Aerosol and Gas Experiment, is the latest version of an experiment that began in 1979 to carefully monitor and precisely measure ozone, aerosols, nitrogen dioxide and water vapor in the stratosphere and troposphere high above Earth. For details about the SAGE III mission, go to  
SpaceX's CRS-10 mission will also carry the Raven experiment, an advanced instrument designed to test sensors and avionics that are being developed so spacecraft can autonomously guide themselves through space to rendezvous and dock with other spacecraft. Raven's two-year mission on the station will see it compare trajectories and calculations with the actual flight paths of the many spacecraft that fly to the station.
The Dragon also carries an experiment coordinated by CASIS that will crystalize a human monoclonal antibody that has been developed by Merck Research Labs to treat immunological diseases. Crystalizing experiments on Earth have not produced high quality samples for study. It is hoped that larger crystals formed in the microgravity of space – where they won't collapse under their own weight as they grow – will show how to make the medicines usable in injected form instead of intravenously.
The SpaceX mission is expected to last about a month with the Dragon capsule being detached from the station by the robotic arm. The Dragon will fly the return flight path on its own as SpaceX and NASA mission controllers watch over its progress. Flying into the atmosphere protected by a heat shield, the Dragon will splashdown in the Pacific Ocean, where it will be recovered and its payloads dispatched to researchers.
By Steven Siceloff,
>NASA's Kennedy Space Center, Florida
The Image
A SpaceX Dragon cargo-carrying spacecraft like the one that will launch for the CRS-10 mission is seen connected to the International Space Station in August 2016.
Credits: NASA
Feb. 16, 2017
#nasa #esa #spaceexploration
Wait while more posts are being loaded