Monday, September 29, 2014

PanSTARRS K1, the Comet that Keeps Going and Going and Going

PanSTARRS K1, the Comet that Keeps Going and Going and Going:

Comet C/2012 K1 PANSTARRS photographed on September 26, 2014 by Rolando Ligustri. Like most comets, we see two tails. K1's dust tails points off to the left, it's gas or ion tail to the right. Credit: Rolando Ligustri


Comet C/2012 K1 PanSTARRS photographed on September 26, 2014. Two tails are seen – a dust tail points off to the left and the gas or ion tail to the right. Copyright: Rolando Ligustri
Thank you K1 PanSTARRS for hanging in there!  Some comets crumble and fade away. Others linger a few months and move on. But after looping across the night sky for more than a year, this one is nowhere near quitting. Matter of fact, the best is yet to come.

This new visitor from the Oort Cloud making its first passage through the inner solar system, C/2012 K1 was discovered in May 2012 by the Pan-STARRS 1 survey telescope atop Mt. Haleakala in Hawaii at magnitude 19.7. Faint! On its the inbound journey from the Oort Cloud, C/2012 K1 approached with an orbit estimated in the millions of years. Perturbed by its interactions with the planets, its new orbit has been reduced to a mere  ~400,000 years.  That makes the many observing opportunities PanSTARRS K1 has provided that much more appreciated. No one alive now will ever see the comet again once this performance is over.

Comet C/2012 K1 PanSTARRS' changing appearance over the past year. Credit upper left clockwise: Carl Hergenrother, Damian Peach, Chris Schur and Rolando Ligustri


Comet C/2012 K1 PanSTARRS’ changing appearance over the past year. Credit upper left clockwise: Carl Hergenrother, Damian Peach, Chris Schur and Rolando Ligustri
Many amateur astronomers first picked up the comet’s trail in the spring of 2013 when it had brightened to around magnitude 13.5. My observing notes from June 2, 2013, read:

“Very small, about 20 arc seconds in diameter. Pretty faint at ~13.5 and moderately condensed but not too difficult at 142x . Well placed in Hercules.” Let’s just say it was a faint, fuzzy blob.

K1 PanSTARRS slowly brightened in Serpens last fall until it was lost in evening twilight. Come January this year it returned to the morning sky a little closer to Earth and Sun and a magnitude brighter. As winter snow gave way to frogs and flowers, the comet rocketed across Corona Borealis, Bootes and Ursa Major. Its fat, well-condensed coma towed a pair of tails and grew bright enough to spot in binoculars at magnitude 8.5 in late May.

Skywatchers can find C/2012 K1 PanSTARRS in the morning just in Hydra-Puppis just before dawn. The map shows its location daily with stars to magnitude 8.5. The numbers next to some stars are standard Flamsteed atllas catalog numbers. Source: Chris Marriott's SkyMap


Skywatchers can find C/2012 K1 PanSTARRS in the morning sky in the Hydra and Puppis just before dawn when it’s highest in the southeastern sky. The map shows its location daily with stars to magnitude 8.5. The numbers next to some stars are standard Flamsteed atlas catalog numbers. Click for a larger version. Source: Chris Marriott’s SkyMap
By July, it hid away in the solar glare a second time only to come back swinging in September’s pre-dawn sky.  Now in the constellation Hydra and even closer to Earth, C/2012 K1 has further brightened to magnitude 7.5. Though low in the southeast at dawn, I was pleasantly surprised to see it several mornings ago. Through my 15-inch (37-cm) reflector at 64x I saw a fluffy, bright coma punctuated by a brighter, not-quite-stellar nucleus and a faint tail extending 1/4ยบ to the northeast.

Mid-northern observers can watch the comet’s antics through mid-October. From then on, K1 will only be accessible from the far southern U.S. and points south as it makes the rounds of Pictor, Dorado and Horologium. After all this time you might think the comet is ready to depart Earth’s vicinity. Not even. C/2012 K1 will finally make its closest approach to our planet on Halloween (88.6 million miles – 143 million km) when it could easily shine at magnitude 6.5, making it very nearly a naked-eye comet.

PanSTARRS K1’s not giving up anytime soon. Southern skywatchers will keep it in view through the spring of 2015 before it returns to the deep chill from whence it came. After delighting skywatchers for nearly two years, it’ll be hard to let this one go.


Tagged as: C/2012 K1 PANSTARRS, coma, comet, Oort cloud

Posted by Nelio Inacio at 3:42 PM 0 comments

Stunning Astrophoto: Milky Way Over Fünfländerblick

Stunning Astrophoto: Milky Way Over Fünfländerblick:

'Fu?nfla?nderblick Milchstrasse,' the Milky Way over a dark country sky in Switzerland. Credit and copyright: Christian Kamber.


‘Fu?nfla?nderblick Milchstrasse,’ the Milky Way over a dark country sky in Switzerland. Credit and copyright: Christian Kamber.
Hey, it’s #MilkyWayMonday! This gorgeous photo of the Milky Way was taken by astrophotographer Christian Kamber near Fu?nfla?nderblick, Switzerland (you can see the region on a map here). This is a stack of 20 shots, made with Deep Sky Stacker and Photoshop.

Lovely!


Want to get your astrophoto featured on Universe Today? Join our Flickr group or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Tagged as: #milkywaymonday, Astrophoto, milky way

Posted by Nelio Inacio at 3:41 PM 0 comments

Behold: 100 Planetary Nebulas

Behold: 100 Planetary Nebulas:

100 colorful planetary nebulae, at apparent size relative to one another. Image processing and collection by Judy Schmidt.


100 colorful planetary nebulae, at apparent size relative to one another. Image processing and collection by Judy Schmidt.
If you like planetary nebulas, you’re in luck. Multimedia artist Judy Schmidt has put together an amazing collection of 100 of these colorful glowing shells of gas and plasma, all at apparent size relative to one another. There’s even a giant-sized 10,000 pixel-wide version available on Flickr.

How many of these planetary nebulae can you identify?

Judy explained her inspiration for putting together this wonderful ‘poster':

Inspired by insect illustration posters, this is a large collage of planetary nebulas I put together bit by bit as I processed them. All are presented north up and at apparent size relative to one another–I did not rotate or resize them in order to satisfy compositional aesthetics (if you spot any errors, let me know). Colors are aesthetic choices, especially since most planetary nebulas are imaged with narrowband filters.
Planetary nebulae are formed by certain types of stars at the end of their lives, and actually have nothing to do with planets. They were given the confusing name 300 years ago by William Herschel because in early, rudimentary telescopes, the puffed out balls of gas looked like planets.

Our own Sun will likely undergo a similar process, but not for another 5 billion years or so.

You can see more of Judy’s work at her website “Geckzilla” or Flickr page.

Tagged as: Judy Schmidt, Planetary Nebula

Posted by Nelio Inacio at 3:41 PM 0 comments

Cold Atom Laboratory Chills Atoms to New Lows

Cold Atom Laboratory Chills Atoms to New Lows: Artist's concept of an atom chip for use by NASA's Cold Atom Laboratory (CAL) Artist's concept of an atom chip for use by NASA's Cold Atom Laboratory (CAL) aboard the International Space Station. CAL will use lasers to cool atoms to ultracold temperatures. Image Credit: NASA
› Full image and caption


September 26, 2014

NASA's Cold Atom Laboratory (CAL) mission has succeeded in producing a state of matter known as a Bose-Einstein condensate, a key breakthrough for the instrument leading up to its debut on the International Space Station in late 2016.

A Bose-Einstein condensate (BEC) is a collection of atoms in a dilute gas that have been lowered to extremely cold temperatures and all occupy the same quantum state, in which all of the atoms have the same energy levels. At a critical temperature, atoms begin to coalesce, overlap and become synchronized like dancers in a chorus line. The resulting condensate is a new state of matter that behaves like a giant -- by atomic standards -- wave.

"It's official. CAL's ground testbed is the coolest spot at NASA's Jet Propulsion Laboratory at 200 nano-Kelvin [200 billionths of 1 Kelvin], "said Cold Atom Laboratory Project Scientist Rob Thompson at JPL in Pasadena, California. "Achieving Bose-Einstein condensation in our prototype hardware is a crucial step for the mission."

Although these quantum gases had been created before elsewhere on Earth, the Cold Atom Laboratory will explore the condensates in an entirely new regime: The microgravity environment of the space station. It will enable groundbreaking research in temperatures colder than any found on Earth.

CAL will be a facility for studying ultra-cold quantum gases on the space station. In the station's microgravity environment, interaction times and temperatures as low as one picokelvin (one trillionth of one Kelvin, or 293 trillion times below room temperature) should be achievable. That's colder than anything known in nature, and the experiments with CAL could potentially create the coldest matter ever observed in the universe. These breakthrough temperatures unlock the potential to observe new quantum phenomena and test some of the most fundamental laws of physics.

First observed in 1995, Bose-Einstein condensation has been one of the "hottest" topics in physics ever since. The condensates are different from normal gases; they represent a distinct state of matter that starts to form typically below a millionth of a degree above absolute zero, the temperature at which atoms have the least energy and are close to motionless. Familiar concepts of "solid," "liquid" and "gas" no longer apply at such cold temperatures; instead, atoms do bizarre things governed by quantum mechanics, such as behaving as waves and particles at the same time.

Cold Atom Laboratory researchers used lasers to optically cool rubidium atoms to temperatures almost a million times colder than that of the depths of space. The atoms were then magnetically trapped, and radio waves were used to cool the atoms 100 times lower. The radiofrequency radiation acts like a knife, slicing away the hottest atoms from the trap so that only the coldest remain.

The research is at the point where this process can reliably create a Bose-Einstein condensate in just seconds.

"This was a tremendous accomplishment for the CAL team. It confirms the fidelity of the instrument system design and provides us a facility to perform science and hardware verifications before we get to the space station," said CAL Project Manager Anita Sengupta of JPL.

While so far, the Cold Atom Laboratory researchers have created Bose-Einstein condensates with rubidium atoms, eventually they will also add in potassium. The behavior of two condensates mixing together will be fascinating for physicists to observe, especially in space.

Besides merely creating Bose-Einstein condensates, CAL provides a suite of tools to manipulate and probe these quantum gases in a variety of ways. It has a unique role as a facility for the atomic, molecular and optical physics community to study cold atomic physics in microgravity, said David Aveline of JPL, CAL ground testbed lead.

"Instead of a state-of-the-art telescope looking outward into the cosmos, CAL will look inward, exploring physics at the atomic scale," Aveline said.

JPL is developing the Cold Atom Laboratory sponsored by the International Space Station Program at NASA's Johnson Space Center in Houston.

The Space Life and Physical Sciences Division of NASA's Human Exploration and Operations Mission Directorate at NASA Headquarters in Washington manages the Fundamental Physics Program.

For more information about the Cold Atom Laboratory visit:

http://coldatomlab.jpl.nasa.gov/

Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau@jpl.nasa.gov

2014-325

Posted by Nelio Inacio at 3:40 PM 0 comments

Rosetta to Deploy Lander on November 12

Rosetta to Deploy Lander on November 12: Image depicts the primary landing site on comet 67P/Churyumov-Gerasimenko Image depicts the primary landing site on comet 67P/Churyumov-Gerasimenko chosen for the European Space Agency's Rosetta mission. Image credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA
› Full image and caption


September 26, 2014

The European Space Agency's Rosetta mission will deploy its lander, Philae, to the surface of comet 67P/Churyumov-Gerasimenko on Nov. 12.

Rosetta is an international mission spearheaded by the European Space Agency with support and instruments provided by NASA.

Philae's landing site, currently known as Site J, is located on the smaller of the comet's two "lobes," with a backup site on the larger lobe. The sites were selected just six weeks after Rosetta's Aug. 6 arrival at the comet, following the spacecraft's 10-year journey through the solar system.

In that time, the Rosetta mission has been conducting an unprecedented scientific analysis of the comet, a remnant from early in the solar system's 4.6-billion-year history. The latest results from Rosetta will be presented when Philae lands, during dedicated press briefings.

The main focus to date has been to survey 67P/Churyumov-Gerasimenko in order to prepare for the first-ever attempt to soft-land on a comet.

The descent to the comet is passive and it is only possible to predict that the landing point will be within a "landing ellipse" (typically a few hundred yards or meters in size). For each of Rosetta's candidate sites, a larger area -- four-tenths of a square mile (one square kilometer) -- was assessed. Site J was chosen unanimously as the primary landing site because the majority of terrain within an area that size has slopes of less than 30 degrees relative to the local vertical and because there are relatively few large boulders. The area also receives sufficient daily illumination to recharge Philae and continue surface science operations beyond the initial 64-hour battery-powered phase.

Over the last two weeks, the flight dynamics and operations teams at ESA have been making a detailed analysis of flight trajectories and timings for Rosetta to deliver the lander at the earliest possible opportunity.

Two robust landing scenarios have been identified, one for the primary site and one for the backup. Both anticipate separation and landing on Nov. 12.

For the primary landing scenario, targeting Site J, Rosetta will release Philae at 08:35 UTC (12:35 a.m. PST; 9:35 a.m. Central European Time) at a distance of 14 miles (22.5 kilometers) from the center of the comet, landing about seven hours later. The one-way signal travel time between Rosetta and Earth on Nov. 12 will be 28 minutes and 20 seconds, meaning that confirmation of the landing will arrive at Earth ground stations at around 16:00 UTC (8 a.m. PST; 5 p.m. CET).

If a decision is made to use the backup site, Site C, separation will occur at 13:04 UTC (5:04 a.m. PST; 2:04 p.m. CET) at a distance of 7.8 miles (12.5 kilometers) from the center of the comet. Landing will occur about four hours later, with confirmation on Earth at around 17:30 UTC (9:30 a.m. PST; 6:30 p.m. CET). The timings are subject to uncertainties of several minutes.

Final confirmation of the primary landing site and its landing scenario will be made on October 14 after a formal Lander Operations Readiness Review, which will include the results of additional high-resolution analysis of the landing sites conducted in the meantime. Should the backup site be chosen at this stage, landing can still occur on Nov. 12.

A competition for the public to name the primary landing site will also be announced during the week of Oct. 14.

Following the Philae landing, the Rosetta orbiter will continue to study the comet and its environment using 11 science instruments for another year as the spacecraft and comet orbit the sun together. The comet is on an elliptical 6.5-year orbit that takes it from beyond Jupiter at its farthest point, to between the orbits of Mars and Earth at its closest to the sun. Rosetta will accompany the comet for more than a year as they swing around the sun and back to the outer solar system again.

The analyses made by the Rosetta orbiter will be complemented by the measurements performed on the comet by Philae's 10 instruments.

Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed. By studying the gas, dust and structure of the nucleus and organic materials associated with the comet, the Rosetta mission should become key to unlocking the history and evolution of our solar system, as well as answering questions regarding the origin of Earth's water and perhaps even life.

Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by the German Aerospace Center, Cologne; Max Planck Institute for Solar System Research, Gottingen; National Center of Space Studies of France (CNES), Paris; and the Italian Space Agency, Rome. NASA's Jet Propulsion Laboratory in Pasadena, California, a division of the California Institute of Technology, manages the U.S. participation in the Rosetta mission for NASA's Science Mission Directorate in Washington.

For more information on the U.S. instruments aboard Rosetta, visit:

http://rosetta.jpl.nasa.gov

More information about Rosetta is available at:

http://www.esa.int/rosetta

DC Agle/Guy Webster
Jet Propulsion Laboratory, Pasadena, Calif.
818-393-9011/818-354-6278
agle@jpl.nasa.gov/guy.webster@jpl.nasa.gov

2014-326

Posted by Nelio Inacio at 3:39 PM 0 comments

Cassini Watches Mysterious Feature Evolve in Titan Sea

Cassini Watches Mysterious Feature Evolve in Titan Sea: Mysterious Changing Feature in Ligeia Mare These three images, created from Cassini Synthetic Aperture Radar (SAR) data, show the appearance and evolution of a mysterious feature in Ligeia Mare, one of the largest hydrocarbon seas on Saturn's moon Titan. Image credit: NASA/JPL-Caltech/ASI/Cornell
› Full image and caption


September 29, 2014

NASA's Cassini spacecraft is monitoring the evolution of a mysterious feature in a large hydrocarbon sea on Saturn's moon Titan. The feature covers an area of about 100 square miles (260 square kilometers) in Ligeia Mare, one of the largest seas on Titan. It has now been observed twice by Cassini's radar experiment, but its appearance changed between the two apparitions.

Images of the feature taken during the Cassini flybys are available at:

http://photojournal.jpl.nasa.gov/catalog/PIA18430

The mysterious feature, which appears bright in radar images against the dark background of the liquid sea, was first spotted during Cassini's July 2013 Titan flyby. Previous observations showed no sign of bright features in that part of Ligeia Mare. Scientists were perplexed to find the feature had vanished when they looked again, over several months, with low-resolution radar and Cassini's infrared imager. This led some team members to suggest it might have been a transient feature. But during Cassini's flyby on August 21, 2014, the feature was again visible, and its appearance had changed during the 11 months since it was last seen.

Scientists on the radar team are confident that the feature is not an artifact, or flaw, in their data, which would have been one of the simplest explanations. They also do not see evidence that its appearance results from evaporation in the sea, as the overall shoreline of Ligeia Mare has not changed noticeably.

The team has suggested the feature could be surface waves, rising bubbles, floating solids, solids suspended just below the surface, or perhaps something more exotic.

The researchers suspect that the appearance of this feature could be related to changing seasons on Titan, as summer draws near in the moon's northern hemisphere. Monitoring such changes is a major goal for Cassini's current extended mission.

"Science loves a mystery, and with this enigmatic feature, we have a thrilling example of ongoing change on Titan," said Stephen Wall, the deputy team lead of Cassini's radar team, based at NASA's Jet Propulsion Laboratory in Pasadena, California. "We're hopeful that we'll be able to continue watching the changes unfold and gain insights about what's going on in that alien sea."

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

For more information about Cassini and its mission, visit:

http://www.nasa.gov/cassini

http://saturn.jpl.nasa.gov

Preston Dyches
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-7013
preston.dyches@jpl.nasa.gov

2014-327

Posted by Nelio Inacio at 3:38 PM 0 comments

Wednesday, September 24, 2014

Prospects have been fading for an El Niรฑo event in 2014, but now there's a glimmer of hope...

Prospects have been fading for an El Niรฑo event in 2014, but now there's a glimmer of hope...: The image shows Kelvin waves of high sea level (red/yellow) crossing the Pacific Ocean at the equator. The image shows Kelvin waves of high sea level (red/yellow) crossing the Pacific Ocean at the equator. The waves can be related to El Niรฑo events. Green indicates normal sea level, and blue/purple areas are lower than normal. Data are from the NASA/European Jason-2 satellite, collected Sept. 13-22, 2014. Image credit: NASA/JPL-Caltech

› Full image and caption


September 22, 2014

Prospects have been fading for an El Niรฑo event in 2014, but now there's a glimmer of hope for a very modest comeback. Scientists warn that unless these developing weak-to-modest El Niรฑo conditions strengthen, the drought-stricken American West shouldn't expect any relief.

The latest sea-level-height data from the NASA/European Ocean Surface Topography Mission (OSTM)/Jason-2 satellite mission show a pair of eastward-moving waves of higher sea level, known as Kelvin waves, in the Pacific Ocean -- the third such pair of waves this year. Now crossing the central and eastern equatorial Pacific, these warm waves appear as the large area of higher-than-normal sea surface heights (warmer-than-normal ocean temperatures) hugging the equator between 120 degrees west and the International Dateline. The Kelvin waves are traveling eastward and should arrive off Ecuador in late September and early October.

A series of larger atmospheric "west wind bursts" from February through May 2014 triggered an earlier series of Kelvin waves that raised hopes of a significant El Niรฑo event. Just as the warming of the eastern equatorial Pacific by these waves dissipated, damping expectations for an El Niรฑo this year, these latest Kelvin waves have appeared, resuscitating hopes for a late arrival of the event.

The new image is online at:

http://www.jpl.nasa.gov/images/earth/elnino/earth20140922-full.jpg

For an overview of 2014's El Niรฑo prospects and Kelvin waves, please see:

http://science.nasa.gov/science-news/science-at-nasa/2014/19may_elnino/

Climatologist Bill Patzert of NASA's Jet Propulsion Laboratory, Pasadena, California, says it's too early to know for sure, but he would not be surprised if the latest Kelvin waves are the "last hurrah" for this much-hoped-for El Niรฑo. "Since February 2014, the prospect of an El Niรฑo has waxed and waned. This late in the season, the best we can expect is a weak to moderate event. What comes next is not yet clear. But for the drought-plagued American West, the possibility of a badly needed drenching is fading," said Patzert.

NASA scientists will continue to monitor the Pacific to see what is in store next for the world's climate.

This image was created with data collected by the U.S./European OSTM/Jason-2 satellite during a 10-day period centered on Sept. 18, 2014. It shows a red and yellow area in the central and eastern equatorial Pacific, indicating that the ocean surface is about 4 to 6 inches (10 to 12 centimeters) above normal. Green indicates near-normal conditions. These regions contrast with the western equatorial Pacific, where sea levels (blue and purple areas) are 3 to 6 inches (8 to 15 centimeters) lower than normal.

The height of the ocean water relates, in part, to its temperature, and thus is an indicator of the amount of heat stored in the ocean below. As the ocean warms, the water expands and the sea level rises; as it cools, its level falls. Above-normal height variations along the equatorial Pacific indicate El Niรฑo conditions, while below-normal height variations indicate La Niรฑa conditions. The temperature of the upper ocean can have a significant influence on weather patterns and climate.

This latest image highlights the processes that occur on time scales of more than a year but usually less than 10 years, such as El Niรฑo and La Niรฑa. The image also highlights faster ocean processes such as Kelvin waves. As Patzert says, "Jason-2 is a fantastic Kelvin wave counter." These processes are known as the interannual ocean signal. To show that signal, scientists refined data for this image by removing trends over the past 21 years, seasonal variations and time-averaged signals of large-scale ocean circulation. For a more detailed explanation of what this type of image means, visit:

http://sealevel.jpl.nasa.gov/science/elninopdo/latestdata/

The comings and goings of El Niรฑo and La Niรฑa are part of the long-term, evolving state of global climate, for which measurements of sea surface height are a key indicator. Jason-2 is a joint effort between NASA, the National Oceanic and Atmospheric Administration (NOAA), the French Space Agency Centre National d'Etudes Spatiales (CNES) and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT). JPL manages the U.S. portion of Jason-2 for NASA's Science Mission Directorate, Washington, D.C. In early 2015, NASA and its international partners CNES, NOAA and EUMETSAT will launch Jason-3, which will extend the timeline of ocean surface topography measurements begun by the Topex/Poseidon and Jason 1 and 2 satellites. Jason-3 will make highly detailed measurements of sea level on Earth to gain insight into ocean circulation and climate change. JPL is a division of the California Institute of Technology.

For a time sequence of the evolution of the 2014 El Nino, visit:

http://sealevel.jpl.nasa.gov/science/elninopdo/latestdata/archive/

To learn more on NASA's satellite altimetry programs, visit:

http://sealevel.jpl.nasa.gov

Alan Buis 818-354-0474

Jet Propulsion Laboratory, Pasadena, California

Alan.Buis@jpl.nasa.gov

2014-319

Posted by Nelio Inacio at 11:06 AM 0 comments

Monday, September 22, 2014

NASA's Newest Mars Mission Spacecraft Enters Orbit around Red Planet

NASA's Newest Mars Mission Spacecraft Enters Orbit around Red Planet: MAVEN (Artist's Concept) This image shows an artist concept of NASA's Mars Atmosphere and Volatile Evolution (MAVEN) mission. Image Credit: NASA/Goddard Space Flight Center

› Full image and caption


September 21, 2014

NASA's Mars Atmosphere and Volatile Evolution (MAVEN) spacecraft successfully entered Mars' orbit at 7:24 p.m. PDT (10:24 p.m. EDT) Sunday, Sept. 21, where it now will prepare to study the Red Planet's upper atmosphere as never done before. MAVEN is the first spacecraft dedicated to exploring the tenuous upper atmosphere of Mars.

"As the first orbiter dedicated to studying Mars' upper atmosphere, MAVEN will greatly improve our understanding of the history of the Martian atmosphere, how the climate has changed over time, and how that has influenced the evolution of the surface and the potential habitability of the planet," said NASA Administrator Charles Bolden. "It also will better inform a future mission to send humans to the Red Planet in the 2030s."

After a 10-month journey, confirmation of successful orbit insertion was received from MAVEN data observed at the Lockheed Martin operations center in Littleton, Colorado, as well as from tracking data monitored at NASA's Jet Propulsion Laboratory navigation facility in Pasadena, California. The telemetry and tracking data were received by NASA's Deep Space Network antenna station in Canberra, Australia.

"NASA has a long history of scientific discovery at Mars and the safe arrival of MAVEN opens another chapter," said John Grunsfeld, astronaut and associate administrator of the NASA Science Mission Directorate at the agency's Headquarters in Washington. "Maven will complement NASA's other Martian robotic explorers-and those of our partners around the globe-to answer some fundamental questions about Mars and life beyond Earth."

Following orbit insertion, MAVEN will begin a six-week commissioning phase that includes maneuvering into its final science orbit and testing the instruments and

science-mapping commands. MAVEN then will begin its one Earth-year primary mission, taking measurements of the composition, structure and escape of gases in Mars' upper atmosphere and its interaction with the sun and solar wind.

"It's taken 11 years from the original concept for MAVEN to now having a spacecraft in orbit at Mars," said Bruce Jakosky, MAVEN principal investigator with the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder (CU/LASP). "I'm delighted to be here safely and successfully, and looking forward to starting our science mission."

The primary mission includes five "deep-dip" campaigns, in which MAVEN's periapsis, or lowest orbit altitude, will be lowered from 93 miles (150 kilometers) to about 77 miles (125 kilometers). These measurements will provide information down to where the upper and lower atmospheres meet, giving scientists a full profile of the upper tier.

"This was a very big day for MAVEN," said David Mitchell, MAVEN project manager from NASA's Goddard Space Flight Center, Greenbelt, Maryland. "We're very excited to join the constellation of spacecraft in orbit at Mars and on the surface of the Red Planet. The commissioning phase will keep the operations team busy for the next six weeks, and then we'll begin, at last, the science phase of the mission. Congratulations to the team for a job well done today."

MAVEN launched Nov. 18, 2013, from Cape Canaveral Air Force Station in Florida, carrying three instrument packages. The Particles and Fields Package, built by the University of California at Berkeley with support from CU/LASP and Goddard, contains six instruments that will characterize the solar wind and the ionosphere of the planet. The Remote Sensing Package, built by CU/LASP, will identify characteristics present throughout the upper atmosphere and ionosphere. The Neutral Gas and Ion Mass Spectrometer, provided by Goddard, will measure the composition and isotopes of atomic particles.

The spacecraft's principal investigator is based at CU/LASP. The university provided two science instruments and leads science operations, as well as education and public outreach, for the mission.

NASA Goddard Space Flight Center manages the project and also provided two science instruments for the mission. Lockheed Martin built the spacecraft and is responsible for mission operations. The Space Sciences Laboratory at the University of California at Berkeley provided four science instruments for MAVEN. JPL provides navigation and Deep Space Network support, and Electra telecommunications relay hardware and operations. JPL, a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Program for NASA.

To learn more about the MAVEN mission, visit:

http://www.nasa.gov/maven

and

http://mars.nasa.gov/maven/

Dwayne Brown

Headquarters, Washington

202-358-1726

dwayne.c.brown@nasa.gov

Nancy Neal-Jones / Elizabeth Zubritsky

Goddard Space Flight Center, Greenbelt, Maryland

301-286-0039 / 301-614-5438

nancy.n.jones@nasa.gov / elizabeth.a.zubritsky@nasa.gov

2014-318

Posted by Nelio Inacio at 5:43 AM 0 comments

Saturday, September 20, 2014

How a Planet Can Mess Up a Star's Looks

How a Planet Can Mess Up a Star's Looks:

Note: An earlier version of this article appeared on Peter Edmonds' blog.

Recently, beautiful photos of auroras have been in the news. These colorful light shows were generated by solar storms, and provide a vivid demonstration of activity on the Sun affecting the Earth. The pummeling experienced by our home planet is an example of our one-way relationship with the Sun: it can have a noticeable effect on the Earth, but the Earth has a negligible effect on the Sun. Further afield in the galaxy, this isn't always the case. In a few other systems planets can have a big effect on their star, changing their looks in surprising ways.



A spectacular picture of auroras by photographer Mike Taylor taken over Unity Pond in Waldo County, Maine on September 12, 2014. Credit: Mike Taylor photography.

As explained in the latest press release from NASA's Chandra X-ray Observatory, an exoplanet called WASP-18b appears to be causing the star it orbits to act much older than it actually is. WASP-18b is an example of a hot Jupiter, with a mass about ten times that of Jupiter and an orbit that is less than 24 hours long. The host star, WASP-18, is estimated to have an age that lies between about 500 million and 2 billion years, relatively young by astronomical standards.

Younger stars tend to be more active stars, with stronger magnetic fields, larger flares, and more intense X-ray emission than their older counterparts. Magnetic activity, flaring, and X-ray emission are linked to the stellar rotation, which generally declines with age. However, when astronomers took a long look with Chandra at WASP-18, they didn’t detect any X-rays. Using established relations between the magnetic activity and X-ray emission of stars and their age indicates that WASP-18 is about 100 times less active than it should be at its age.

The researchers argue that tidal forces from the gravitational pull of the massive planet – similar to those the Moon has on Earth’s tides but on a much larger scale – may have disrupted the magnetic field of the star. The strength of the magnetic field depends on the amount of convection in the star. Convection is the process where hot gas stirs the interior of the star.

The planet’s gravity may cause motions of gas in the interior of the star that weaken the convection, causing the magnetic field to weaken and activity to decline. This causes the appearance of premature aging in the star. WASP-18 is thought to have a shallow convection zone, making it unusually susceptible to tidal effects.



Shown in the main part of this graphic is an artist's impression of the star WASP-18 and, in the foreground, its hot Jupiter WASP-18b. The insets show the star in the optical image and its non-detection in X-rays with Chandra. Credit: X-ray: NASA/CXC/SAO/I.Pillitteri et al; Optical: DSS; Illustration: NASA/CXC/M.Weiss

What about other hot Jupiters that are relatively massive and close to their star? In some cases - where they orbit a different type of star to WASP-18 - the effect of hot Jupiters can be flipped and they can make a star appear younger than it really is. In the cases of HD 189733 and CoRoT-2a the presence of the planet appears to have increased the amount of activity in the star. In these cases the stars have much deeper convection zones than WASP-18 and tidal effects have little influence on convection and hence on the star's dynamo. Instead, the planets may be speeding up their star's rotation, leading to a more powerful dynamo and more activity than expected for the star's age. In these cases having a companion makes the star act younger than it really is. That makes sense for people and, in a few cases, for stars.



An artist's impression of the star CoRoT-2a and its hot Jupiter exoplanet, CoRoT-2b. Credit: NASA/CXC/M.Weiss

I've discussed the effects that extreme hot Jupiters can have on their host star. In such systems, what effect does the star have on its planet? In the cases of HD 189733 and CoRoT-2a, strong X-rays and ultraviolet radiation from the active star are evaporating the atmospheres of the planet. For HD 189733, astronomers estimate the planet is losing 100 to 600 million kilograms per second, and for CoRoT-2a astronomers estimate the planet is losing about 5 billion kilograms per second. For WASP-18, with much weaker X-ray emission and ultraviolet radiation, there is much less evaporation of the nearby planet's upper atmosphere than there would be if the star was more active. In effect, the planet is protecting itself. Its gravity causes the nearby star to be less active, and that causes the planet to be struck with less damaging radiation. HD 189733b and CoRoT-2b, on the other hand, are behaving in a self-destructive manner.

Talk of planet destruction isn’t necessary for our present-day solar system, where the planets are much further away from the Sun than hot Jupiters are. However, that won’t always be the case. A few billion years in the future, the Sun will dramatically expand in size when it becomes a red giant. Our oceans will boil away, never to return and what’s left of the Earth may end up spiraling in towards the Sun. We don't know the exact fate of our home planet, but it is clear that our aurora-viewing days are numbered.

Peter Edmonds, CXC

Posted by Nelio Inacio at 1:28 PM 0 comments

Saturn-Circling Cassini Spacecraft Plumbs Titan’s Seas Next Week

Saturn-Circling Cassini Spacecraft Plumbs Titan’s Seas Next Week:

Titan's thick haze. Image: NASA/JPL/Space Science Institute.


Titan’s thick haze. Image: NASA/JPL/Space Science Institute.
Is the surf up yet on Titan? As the moon of Saturn moves towards northern summer, scientists are trying to spot signs of the winds picking up. This weekend, the Cassini spacecraft plans a look at the the largest body of liquid on Titan, Kraken Mare, to see if there are any waves on this huge hydrocarbon sea.

Cassini will make the 105th flyby of Titan on Monday (Sept. 22) to probe the moon’s atmosphere, seas and even a crater. The spacecraft will examine “the seas and lakes of the northern polar area, including Kraken and Ligeia at resolution better than 3 miles (5 kilometers) per pixel,” the Cassini website stated.

Besides wet areas of Titan, Cassini will also look at dunes and the relatively fresh-looking Sinlap crater, where scientists hope to get a high-resolution image. Managers also plan a mosaic of Tsegihi — a bright zone south of the equator — and the darker dune-filled area of Fensal. The spacecraft additionally will examine aerosols and the transparency of hazes in Titan’s atmosphere.

Titan is of interest to scientists in part because its chemistry is a possible precursor to what made life possible. Earlier this week, Cassini transmitted several raw images of its view of Titan and Saturn right now — some of the latest pictures are below.

A raw image of Saturn's moon Titan taken by the Cassini spacecraft Sept. 14, 2014. Credit: NASA/JPL/Space Science Institute


A raw image of Saturn’s moon Titan taken by the Cassini spacecraft Sept. 14, 2014. Credit: NASA/JPL/Space Science Institute
Atmospheric features on Saturn's moon Titan appear to be faintly visible in this raw image taken by the Cassini spacecraft Sept. 10, 2014. Credit: NASA/JPL/Space Science Institute


Atmospheric features on Saturn’s moon Titan appear to be faintly visible in this raw image taken by the Cassini spacecraft Sept. 10, 2014. Credit: NASA/JPL/Space Science Institute
A crescent Titan beckons the Cassini spacecraft (in Saturn's system) in this image taken Aug. 24, 2014. Credit: NASA/JPL/Space Science Institute


A crescent Titan beckons the Cassini spacecraft (in Saturn’s system) in this image taken Aug. 24, 2014. Credit: NASA/JPL/Space Science Institute
A raw image of Saturn taken by the Cassini spacecraft Sept. 15, 2014. Credit: NASA/JPL/Space Science Institute


A raw image of Saturn taken by the Cassini spacecraft Sept. 15, 2014. Credit: NASA/JPL/Space Science Institute
Posted by Nelio Inacio at 1:26 PM 0 comments

This Exoplanet Has Prematurely Aged its Star

This Exoplanet Has Prematurely Aged its Star:

X-ray: NASA/CXC/SAO/I.Pillitteri et al; Optical: DSS; Illustration: NASA/CXC/M.Weiss


Optical and X-ray images of the star WASP 18. X-ray Credit: NASA / CXC / SAO / I.Pillitteri et al; Optical Credit: DSS; Illustration Credit: NASA / CXC / M.Weiss
Hot young stars are wildly active, emitting huge eruptions of charged particles form their surfaces. But as they age they naturally become less active, their X-ray emission weakens and their rotation slows.

Astronomers have theorized that a hot Jupiter — a sizzling gas giant circling close to its host star — might be able to sustain a young star’s activity, ultimately prolonging its youth. Earlier this year, two astronomers from the Harvard-Smithsonian Center for Astrophysics tested this hypothesis and found it true.

But now, observations of a different system show the opposite effect: a planet that’s causing its star to age much more quickly.

The planet, WASP-18b has a mass roughly 10 times Jupiter’s and circles its host star in less than 23 hours. So it’s not exactly a classic hot Jupiter — a sizzling gas giant whipping around its host star — because it’s characteristics are a little more drastic.

“WASP-18b is an extreme exoplanet,” said lead author Ignazio Pillitteri of the National Institute for Astrophysics in Italy, in a news release. “It is one of the most massive hot Jupiters known and one of the closest to its host star, and these characteristics lead to unexpected behavior.”

The team thinks WASP-18 is 600 million years old, relatively young compared to our 5-billion-year-old Sun. But when Pillitteri and colleagues took a long look with NASA’s Chandra X-ray Observatory at the star, they didn’t see any X-rays — a telltale sign the star is youthful. In fact, the observations show the star is 100 times less active than it should be.

“We think the planet is aging the star by wreaking havoc on its innards,” said co-author Scott Wolk (who also worked on the previous study showing the opposite effect) from the Harvard-Smithsonian Center for Astrophysics.

The researchers argue that tidal forces created by the gravitational pull of the massive planet might have disrupted the star’s magnetic field generated by the motion of conductive plasma deep inside the star. It’s possible the exoplanet significantly interfered with the upper layers of the convective zone, reduced any mixing of stellar material, and effectively canceled out the magnetic activity.

The effect of tidal forces from the planet may also explain an unusually high amount of lithium seen in the star. Lithium is usually abundant in younger stars, but disappears over time as convection carries it further toward the star’s center, where it’s destroyed by nuclear reactions. So if there’s less convection — as seems to be the case for WASP 18 — then the lithium won’t circulate toward the center of the star and instead will survive.

The findings have been published in the July issue of Astronomy and Astrophysics and are available online.

Posted by Nelio Inacio at 1:25 PM 0 comments

Stunning Photo Alert! Winners Announced for “Astronomy Photographer of the Year” Competition

Stunning Photo Alert! Winners Announced for “Astronomy Photographer of the Year” Competition:

Aurora over a Glacier Lagoon. Credit and copyright: James Woodend, UK


Aurora over a Glacier Lagoon. Credit and copyright: James Woodend, UK
The winners of the 2014 “Astronomy Photographer of the Year” competition have been announced at the Royal Observatory in Greenwich England, and British photographer James Woodend’s gorgeous image of the aurora dancing across the Icelandic night sky was named the overall winner. This is the sixth year for the competition, which is run by the ROG and the Sky at Night Magazine.

“Every year the competition becomes more and more challenging to judge and we’re always astounded by the skill of the photographers,” said Dr. Maggie Aderin-Pocock, a presenter on The Sky at Night and one of the judges for the competition. “The Deep Space category, where the entrants have been able to capture such amazing details of objects light-years away and are almost on par with images taken by the Hubble Space Telescope, never fails to impress.”

See more gorgeous images and a list of the winners in the various categories below:


Earth and Space

James Woodend (UK) with Aurora over a Glacier Lagoon (Winner and Overall Winner)
Matt James (Australia) with Wind Farm Star Trails (Runner-up)
Patrick Cullis (USA) with Moon Balloon (Highly Commended)
Catalin Beldea (Romania) with Totality from Above the Clouds (Highly Commended)
O Chul Kwon (South Korea) with Venus-Lunar Occultation (Highly Commended)

Horsehead Nebula (IC 434). Credit and copyright: Bill Snyder, USA.


Horsehead Nebula (IC 434). Credit and copyright: Bill Snyder, USA.
Deep Space

Bill Snyder (USA) with Horsehead Nebula (IC 434) (Winner)
David Fitz-Henry (Australia) with The Helix Nebula (NGC 7293) (Runner-Up)
J.P Metsรคvainio (Finland) with Veil Nebula Detail (IC 1340) (Highly Commended)
Rogelio Bernal Andreo (USA) with California vs Pleiades (Highly Commended)
Marco Lorenzi (China) with At the Feet of Orion (NGC 1999) – Full Field (Highly Commended)

Stunning closeup of our Sun, entitled 'Ripples in a Pond.' Credit and copyright: Alexandra Hart, UK


Stunning closeup of our Sun, entitled ‘Ripples in a Pond.’ Credit and copyright: Alexandra Hart, UK
Our Solar System
Alexandra Hart (UK) with Ripples in a Pond (Winner)
George Tarsoudis (Greece) with Best of the Craters (Runner-Up)
Alexandra Hart (UK) with Solar Nexus (Highly Commended)
Stephen Ramsden (USA) with Calcium K Eruption (Highly Commended)
Tunรง Tezel (Turkey) with Diamond and Rubies (Highly Commended)

The Horsehead Nebula (IC 434). Credit and copyright: Shishir and Shashank Dholakia, USA, Aged 15.


The Horsehead Nebula (IC 434). Credit and copyright: Shishir and Shashank Dholakia, USA, Aged 15.
Young Astronomy Photographer of the Year

Shishir & Shashank Dholakia (USA, aged 15) with The Horsehead Nebula (IC 434) (Winner)
Emmett Sparling (Canada, aged 15) with New Year over Cypress Mountain (Runner-up)
Olivia Williamson (UK, aged 10) with The Martian Territory (Highly Commended)
Shishir & Shashank Dholakia (USA, aged 15) with The Heart Nebula (IC 1805) (Highly Commended)
Emily Jeremy (UK, aged 12) with Moon Behind the Trees (Highly Commended)

Hybrid Solar Eclipse. Credit and copyright: Eugen Kamenew, Germany


Hybrid Solar Eclipse. Credit and copyright: Eugen Kamenew, Germany
Special Prize: People and Space
Eugen Kamenew (Germany) with Hybrid Solar Eclipse 2 (Winner)
Julie Fletcher (Australia) with Lost Souls (Runner-up)

Coastal Stairways. Credit and copyright: Chris Murphy, New Zealand


Coastal Stairways. Credit and copyright: Chris Murphy, New Zealand
Special Prize: Sir Patrick Moore prize for Best Newcomer

Chris Murphy (New Zealand) with Coastal Stairways (Winner)

NGC 3718 via a robotic scope, Credit and copyright: Mark Hanson, USA


NGC 3718 via a robotic scope, Credit and copyright: Mark Hanson, USA
Robotic Scope Image of the Year

Mark Hanson (USA) with NGC 3718 (Winner)

For all the winners see the ROG website, and for other photos not shown here, you can see more at the Astronomy Photographer of the Year Flickr site . If you are in the UK, you can see an exhibition of the winning photos as the Astronomy Centre, Royal Observatory, Greenwich, from now until February 22, 2015.

Find more info at the ROG website, where you can also find info about the competition for next year — start planning ahead!

Tagged as: Astronomy Photographer of the Year, Astrophotos, Royal Observatory Grenwich

Posted by Nelio Inacio at 1:24 PM 0 comments

How NASA’s Next Mars Spacecraft Will Greet The Red Planet On Sunday

How NASA’s Next Mars Spacecraft Will Greet The Red Planet On Sunday:

An artist concept of MAVEN in orbit around Mars. (Credit: NASA's Goddard Spaceflight Center).

An artist concept of MAVEN in orbit around Mars. (Credit: NASA’s Goddard Spaceflight Center).
NASA’s Mars Atmosphere and Volatile Evolution (MAVEN) orbiter is oh-so-close to its destination after a 10-month journey. It’s scheduled to arrive in orbit Sunday (Sept. 21) around 9:50 p.m. EDT (1:50 a.m. UTC) if all goes well, but there are a few things that need to happen, in order, first.

One big obstacle is already out of the way. MAVEN controllers had expected to do final engine burn tweaks to put it on the right trajectory, but the mission is so on-target that it won’t be needed.

“#MAVEN orbit insertion sequence has been activated on the s/c. No additional ground intervention is needed to enter #Mars’ orbit on Sunday,” the official account tweeted yesterday (Sept. 18).

So what does the sequence entail? MAVEN will need to turn on its six thruster engines for a 33-minute braking maneuver to slow it down. This will allow the gravity of Mars to “capture” the spacecraft into an elliptical or oval-shaped orbit.



Should that all go safely, MAVEN still has a lot of work to do before being ready to capture information about the upper atmosphere of the Red Planet. All spacecraft go through a commissioning phase to ensure their instruments are working correctly and that they are in the correct orbit and orientation to do observations.

As such, controllers will spend about six weeks moving MAVEN into a more circular orbit and testing out its instruments. Usually this period is done without interruption, but NASA wants to capture information when Comet Siding Spring comes whizzing by Mars Oct. 19.

Controllers are interested in learning about the comet and its effect on the upper atmosphere, so they will stop the commissioning to make those measurements. MAVEN will also be oriented in such a way that its solar panels are protected as much as possible from the dust, although scientists now believe the risk of strikes is very low.

This graphic depicts the orbit of comet C/2013 A1 Siding Spring as it swings around the sun in 2014. On Oct. 19, 2014 the comet will have a very close pass at Mars. Its nucleus will miss Mars by about 82,000 miles (132,000 kilometers). Credit: NASA/JPL-Caltech

This graphic depicts the orbit of comet C/2013 A1 Siding Spring as it swings around the sun in 2014. On Oct. 19, 2014 the comet will have a very close pass at Mars. Its nucleus will miss Mars by about 82,000 miles (132,000 kilometers). Credit: NASA/JPL-Caltech
MAVEN is expected to work at Mars for a year, but investigators are hoping it will be for longer so that the atmosphere can be tracked through more of a solar cycle. The Sun’s activity is a major influencer on the atmosphere and the “stripping” of molecules from it over time, which could have thinned Mars’ atmosphere in the ancient past.

The spacecraft will also serve as a backup communications and data relay for the Opportunity and Curiosity rovers on the surface, which might be needed if some of the older NASA Mars spacecraft that fulfill that function experience technical difficulties.


Tagged as: C/2013 A1 Siding Spring, MAVEN

Posted by Nelio Inacio at 1:23 PM 0 comments

Lazy Giant Galaxies Gain Mass By Ingesting Smaller Neighbors

Lazy Giant Galaxies Gain Mass By Ingesting Smaller Neighbors:

Some of the many thousands of merging galaxies identified within the GAMA survey. Credit: Professor Simon Driver and Dr Aaron Robotham, ICRAR.


Some of the many thousands of merging galaxies identified within the GAMA survey. Credit: Professor Simon Driver and Dr Aaron Robotham, ICRAR.
The Anglo-Australian Telescope in New South Wales has been watching how lazy giant galaxies gain size – and it isn’t because they create their own stars. In a research project known as the Galaxy And Mass Assembly (GAMA) survey, a group of Australian scientists led by Professor Simon Driver at the International Centre for Radio Astronomy Research (ICRAR) have found the Universe’s most massive galaxies prefer “eating” their neighbors.

According to findings published in the journal “Monthly Notices of the Royal Astronomical Society”, astronomers studied more than 22,000 individual galaxies to see how they grew. Apparently smaller galaxies are exceptional star producers, forming their stellar members from their own gases. However, larger galaxies are lazy. They aren’t very good at stellar creation. These massive monsters rarely produce new stars on their own. So how do they grow? They cannibalize their companions. Dr. Aaron Robotham, who is based at the University of Western Australia node of the International Centre for Radio Astronomy Research (ICRAR), explains that smaller ‘dwarf’ galaxies were being consumed by their heavyweight peers.

“All galaxies start off small and grow by collecting gas and quite efficiently turning it into stars,” he said. “Then every now and then they get completely cannibalized by some much larger galaxy.”

So how does our home galaxy stack up to these findings? Dr. Robotham, who led the research, said the Milky Way is at a tipping point and is expected to now grow mainly by eating smaller galaxies, rather than by collecting gas.

“The Milky Way hasn’t merged with another large galaxy for a long time but you can still see remnants of all the old galaxies we’ve cannibalized,” he said. “We’re also going to eat two nearby dwarf galaxies, the Large and Small Magellanic Clouds, in about four billion years.” Robotham also added the Milky Way wouldn’t escape unscathed. Eventually, in about five billion years, we’ll encounter the nearby Andromeda Galaxy and the tables will be turned. “Technically, Andromeda will eat us because it’s the more massive one,” he said.

This simulation shows what will happen when the Milky Way and Andromeda get closer together and then collide, and then finally come together once more to merge into an even bigger galaxy.
Simulation Credit: Prof Chris Power (ICRAR-UWA), Dr Alex Hobbs (ETH Zurich), Prof Justin Reid (University of Surrey), Dr Dave Cole (University of Central Lancashire) and the Theoretical Astrophysics Group at the University of Leicester. Video Production Credit: Pete Wheeler, ICRAR.
What exactly is going on here? Is it a case of mutual attraction? According to Dr. Robotham when galaxies grow, they acquire a heavy-duty gravitational field allowing them to suck in neighboring galaxies with ease. But why do they stop producing their own stars? Is it because they have exhausted their fuel? Robotham said star formation slow downs in really massive galaxies might be “because of extreme feedback events in a very bright region at the center of a galaxy known as an active galactic nucleus.”

“The topic is much debated, but a popular mechanism is where the active galactic nucleus basically cooks the gas and prevents it from cooling down to form stars,” Dr. Robotham said.

Will the entire Universe one day become just a single, large galaxy? In reality, gravity may very well cause galaxies groups and clusters to congeal into a limited number of super-giant galaxies, but that will take many billions of years to occur.

“If you waited a really, really, really long time that would eventually happen, but by really long I mean many times the age of the Universe so far,” Dr. Robotham said.

While the GAMA survey findings didn’t take billions of years, it didn’t happen overnight either. It took seven years and more than 90 scientists to complete – and it wasn’t a single revelation. From this work there have been over 60 publications and there are still another 180 in progress!

Original Story Souce: Monster galaxies gain weight by eating smaller neighbours – ICAR

Further reading: ‘Galaxy and Mass Assembly (GAMA): Galaxy close-pairs, mergers and the future fate of stellar mass’ in the Monthly Notices of the Royal Astronomical Society. Published online 19/9/2014 at: http://mnras.oxfordjournals.org/lookup/doi/10.1093/mnras/stu1604 . Preprint version accessible at: http://arxiv.org/abs/1408.1476 .


Tagged as: Galaxy And Mass Assembly (GAMA) Survey, Galaxy Mergers, International Centre for Radio Astronomy Research (ICRAR)

Posted by Nelio Inacio at 1:22 PM 0 comments

Thursday, September 18, 2014

New Horizons Sights Tiny Pluto Moon As Spacecraft Races Toward Dwarf Planet

New Horizons Sights Tiny Pluto Moon As Spacecraft Races Toward Dwarf Planet:

Artist's conception of the New Horizons spacecraft flying past Pluto and Charon, one of the dwarf planet's moons. Credit: Johns Hopkins University/APL


Artist’s conception of the New Horizons spacecraft flying past Pluto and Charon, one of the dwarf planet’s moons. Credit: Johns Hopkins University/APL
Here’s Hydra! The New Horizons team spotted the tiny moon of Pluto in July, about six months ahead of when they expected to. You can check it out in the images below. The find is exciting in itself, but it also bodes well for the spacecraft’s search for orbital debris to prepare for its close encounter with the system in July 2015.

Most of Pluto’s moons were discovered while New Horizons was under development, or already on its way. Mission planners are thus concerned that there could be moons out there that aren’t discovered yet — moons that could pose a danger to the spacecraft if it ended up in the wrong spot at the wrong time.  That’s why the team is engaging in long-range views to see what else is lurking in Pluto’s vicinity.

“We’re thrilled to see it, because it shows that our satellite-search techniques work, and that our camera is operating superbly. But it’s also exciting just to see a third member of the Pluto system come into view, as proof that we’re almost there,” stated science team member John Spencer, of the Southwest Research Institute.



Watch the difference: Pluto’s moon Hydra stands out in these images taken by the New Horizons spacecraft on July 18 and 20, 2014. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute
Hydra was spotted using the spacecraft’s Long Range Reconnaissance Imager (LORRI), which took 48 images of 10 seconds apiece between July 18 and July 20. Then the team used half the images, the ones that show Hydra better, to create the images you see above.

The spacecraft was still 267 million miles (430 million kilometers) from Pluto when the images were taken. Another moon discovered around the same time as Hydra — Nix — is still too close to be seen given it’s so close to Pluto, but just wait.

Meanwhile, scientists are busily trying to figure out where to send New Horizons after Pluto. In July, researchers using the Hubble Space Telescope began a full-scale search for a suitable Kuiper Belt Object, which would be one of trillions of icy or rocky objects beyond Neptune’s orbit. Flying past a KBO would provide more clues as to how the Solar System formed, since these objects are considered leftovers of the chunks of matter that came together to form the planets.

Source: Johns Hopkins Applied Physics Laboratory


Tagged as: Hydra, long range reconnaissance imager, lorri, Nix

Posted by Nelio Inacio at 5:09 AM 0 comments
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