Wednesday, January 7, 2015

Hearing the Early Universe’s Scream: Sloan Survey Announces New Findings

Hearing the Early Universe’s Scream: Sloan Survey Announces New Findings:



A still photo from an animated flythrough of the universe using SDSS data. This image shows our Milky Way Galaxy. The galaxy shape is an artist’s conception, and each of the small white dots is one of the hundreds of thousands of stars as seen by the SDSS. Image credit: Dana Berry / SkyWorks Digital, Inc. and Jonathan Bird (Vanderbilt University)


A still photo from an animated flythrough of the universe using SDSS data. This image shows our Milky Way Galaxy. The galaxy shape is an artist’s conception, and each of the small white dots is one of the hundreds of thousands of stars as seen by the SDSS. Image credit:
Dana Berry / SkyWorks Digital, Inc. and Jonathan Bird (Vanderbilt University)
Imagine a single mission that would allow you to explore the Milky Way and beyond, investigating cosmic chemistry, hunting planets, mapping galactic structure, probing dark energy and analyzing the expansion of the wider Universe. Enter the Sloan Digital Sky Survey, a massive scientific collaboration that enables one thousand astronomers from 51 institutions around the world to do just that.

At Tuesday’s AAS briefing in Seattle, researchers announced the public release of data collected by the project’s latest incarnation, SDSS-III. This data release, termed “DR12,” represents the survey’s largest and most detailed collection of measurements yet: 2,000 nights’ worth of brand-new information about nearly 500 million stars and galaxies.

One component of SDSS is exploring dark energy by “listening” for acoustic oscillation signals from the the acceleration of the early Universe, and the team also shared a new animated “fly-through” of the Universe that was created using SDSS data.


The SDSS-III collaboration is based at the powerful 2.5-meter Sloan Foundation Telescope at the Apache Point Observatory in New Mexico. The project itself consists of four component surveys: BOSS, APOGEE, MARVELS, and SEGUE. Each of these surveys applies different trappings to the parent telescope in order to accomplish its own, unique goal.

BOSS (the Baryon Oscillation Spectroscopic Survey) visualizes the way that sound waves produced by interacting matter in the early Universe are reflected in the large-scale structure of our cosmos. These ancient imprints, which date back to the first 500,000 years after the Big Bang, are especially evident in high-redshift objects like luminous-red galaxies and quasars. Three-dimensional models created from BOSS observations will allow astronomers to track the expansion of the Universe over a span of 9 billion years, a feat that, later this year, will pave the way for rigorous assessment of current theories regarding dark energy.

At the press briefing, Daniel Eistenstein from the Harvard-Smithsonian Center for Astrophysics explained how BOSS requires huge volumes of data and that so far 1.4 million galaxies have been mapped. He indicated the data analyzed so far strongly confirm dark energy’s existence.

This tweet from the SDSS twitter account uses a bit of humor to explain how BOSS works:

It turns out that in space, everyone can hear you scream, if you do it in the early Universe and set up acoustic oscillations #aas225

— SDSS — J. Johnson (@sdssurveys) January 6, 2015
APOGEE (the Apache Point Observatory Galactic Evolution Experiment) employs a sophisticated, near-infrared spectrograph to pierce through thick dust and gather light from 100,000 distant red giants. By analyzing the spectral lines that appear in this light, scientists can identify the signatures of 15 different chemical elements that make up the faraway stars – observations that will help researchers piece together the stellar history of our galaxy.

MARVELS (the Multi-Object APO Radial Velocity Exoplanet Large-Area Survey) identifies minuscule wobbles in the orbits of stars, movements that betray the gravitational influence of orbiting planets. The technology itself is unprecedented. “MARVELS is the first large-scale survey to measure these tiny motions for dozens of stars simultaneously,” explained the project’s principal investigator Jian Ge, “which means we can probe and characterize the full population of giant planets in ways that weren’t possible before.”

At the press briefing, Ge said that MARVELS observed 5,500 stars repeatedly, looking for giant exoplanets around these stars. So far, the data has revealed 51 giant planet candidates as well as 38 brown dwarf candidates. Ge added that more will be found with better data processing.



A still photo from an animated flythrough of the universe using SDSS data. This image shows a small part of the large-scale structure of the universe as seen by the SDSS -- just a few of many millions of galaxies. The galaxies are shown in their proper positions from SDSS data. Image credit: Dana Berry / SkyWorks Digital, Inc.


A still photo from an animated flythrough of the universe using SDSS data. This image shows a small part of the large-scale structure of the universe as seen by the SDSS — just a few of many millions of galaxies. The galaxies are shown in their proper positions from SDSS data. Image credit: Dana Berry / SkyWorks Digital, Inc.
SEGUE (the Sloan Extension for Galactic Understanding and Exploration) rounds out the quartet by analyzing visible light from 250,000 stars in the outer reaches of our galaxy. Coincidentally, this survey’s observations “segue” nicely into work being done by other projects within SDSS-III. Constance Rockosi, leader of the SDSS-III domain of SEGUE, recaps the importance of her project’s observations of our outer galaxy: “In combination with the much more detailed view of the inner galaxy from APOGEE, we’re getting a truly holistic picture of the Milky Way.”

One of the most exceptional attributes of SDSS-III is its universality; that is, every byte of juicy information contained in DR12 will be made freely available to professionals, amateurs, and lay public alike. This philosophy enables interested parties from all walks of life to contribute to the advancement of astronomy in whatever capacity they are able.

As momentous as the release of DR12 is for today’s astronomers, however, there is still much more work to be done. “Crossing the DR12 finish line is a huge accomplishment by hundreds of people,” said Daniel Eisenstein, director of the SDSS-III collaboration, “But it’s a big universe out there, so there is plenty more to observe.”

DR12 includes observations made by SDSS-III between July 2008 and June 2014. The project’s successor, SDSS-IV, began its run in July 2014 and will continue observing for six more years.

Here is the video animation of the fly-through of the Universe:





About 

Vanessa earned her bachelor's degree in Astronomy and Physics in 2009 from Wheaton College in Massachusetts. Her credits in astronomy include observing and analyzing eclipsing binary star systems and taking a walk on the theory side as a NSF REU intern, investigating the expansion of the Universe by analyzing its traces in observations of type 1a supernovae. In her spare time she enjoys writing about astrophysics, cosmology, biology, and medicine, making delicious vegetarian meals, taking adventures with her husband and/or Nikon D50, and saving the world.
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Japan’s Akatsuki Spacecraft to Make Second Attempt to Enter Orbit of Venus in December 2015

Japan’s Akatsuki Spacecraft to Make Second Attempt to Enter Orbit of Venus in December 2015:

Artist’s impression of the Venus Climate Orbiter (aka. “Akatsuki”) by Akihiro Ikeshita. Image Credit: JAXA


Artist’s impression of the Venus Climate Orbiter (aka. “Akatsuki”) by Akihiro Ikeshita.
Image Credit: JAXA
Back in 2010, the Japanese Aerospace Exploration Agency (JAXA) launched the The Venus Climate Orbiter “Akatsuki” with the intention of learning more about the planet’s weather and surface conditions. Unfortunately, due to engine trouble, the probe failed to make it into the planet’s orbit.

Since that time, it has remained in a heliocentric orbit, some 134 million kilometers from Venus, conducting scientific studies on the solar wind. However, JAXA is going to make one more attempt to slip the probe into Venus’ orbit before its fuel runs out.

Since 2010, JAXA has been working to keep Akatsuki functioning so that they could give the spacecraft another try at entering Venus’ orbit.

After a thorough examination of all the possibilities for the failure, JAXA determined that the probe’s main engine burned out as it attempted to decelerate on approach to the planet. They claim this was likely due to a malfunctioning valve in the spacecraft’s fuel pressure system caused by salt deposits jamming the valve between the helium pressurization tank and the fuel tank. This resulted in high temperatures that damaged the engine’s combustion chamber throat and nozzle.



A radar view of Venus taken by the Magellan spacecraft, with some gaps filled in by the Pioneer Venus orbiter. Credit: NASA/JPL


A radar view of Venus taken by the Magellan spacecraft, with some gaps filled in by the Pioneer Venus orbiter. Credit: NASA/JPL
JAXA adjusted the spacecraft’s orbit so that it would establish a heliocentric orbit, with the hopes that it would be able to swing by Venus again in the future. Initially, the plan was to make another orbit insertion attempt by the end 2016 when the spacecraft’s orbit would bring it back to Venus. But because the spacecraft’s speed has slowed more than expected, JAXA determined if they slowly decelerated Akatsuki even more, Venus would “catch up with it” even sooner. A quicker return to Venus would also be advantageous in terms of the lifespan of the spacecraft and its equipment.

But this second chance will likely be the final chance, depending on how much damage there is to the engines and other systems. The reasons for making this final attempt are quite obvious. In addition to providing vital information on Venus’ meteorological phenomena and surface conditions, the successful orbital insertion of Akatsuki would also be the first time that Japan deployed a satellite around a planet other than Earth.

If all goes well, Akatsuki will enter orbit around Venus at a distance of roughly 300,000 to 400,000 km from the surface, using the probe’s 12 smaller engines since the main engine remains non-functional. The original mission called for the probe to establish an elliptical orbit that would place it 300 to 80,000 km away from Venus’ surface.

This wide variation in distance was intended to provide the chance to study the planet’s meteorological phenomena and its surface in detail, while still being able to observe atmospheric particles escaping into space.



Artist's impression of Venus Express entering orbit in 2006. Credit: ESA - AOES Medialab


Artist’s impression of Venus Express entering orbit in 2006. Image Credit: ESA – AOES Medialab
At a distance of 400,000 km, the image quality and opportunities to capture them are expected to be diminished. However, JAXA is still confident that it will be able to accomplish most of the mission’s scientific goals.

In its original form, these goals included obtaining meteorological information on Venus using four cameras that capture images in the ultraviolet and infrared wavelengths. These would be responsible for globally mapping clouds and peering beneath the veil of the planet’s thick atmosphere.

Lightning would be detected with a high-speed imager, and radio-science monitors would observe the vertical structure of the atmosphere. In so doing, JAXA hopes to confirm the existence of surface volcanoes and lighting, both of which were first detected by the ESA’s Venus Express spacecraft. One of the original aims of Akatsuki was to compliment the Venus Express mission. But Venus Express has now completed its mission, running out of gas and plunging into the planet’s atmosphere.

But most of all, it is hoped that Akatsuki can provide observational data on the greatest mystery of Venus, which has to do with its surface storms.



Artists impression of lightning storms on Venus. Credit: ESA


Artists impression of lightning storms on Venus. Credit: ESA
Previous observations of the planet have shown that winds that can reach up to 100 m/s (360 km/h or ~225 mph) circle the planet every four to five Earth days. This means that Venus experiences winds that are up to 60 times faster than the speed at which the planet turns, a phenomena known as “Super-rotation”.

Here on Earth, the fastest winds are only capable of reaching between 10 and 20 percent of the planet’s rotation. As such, our current meteorological understanding does not account for these super-high speed winds, and it is hoped that more information on the atmosphere will provide some clues as to how this can happen.

Between the extremely thick clouds, sulfuric rain storms, lightning, and high-speed winds, Venus’ atmosphere is certainly very interesting! Add to the fact that the volcanic, pockmarked surface cannot be surveyed without the help of sophisticated radar or IR imaging, and you begin to understand why JAXA is eager to get their probe into orbit while they still can.

And be sure to check out this video, courtesy of JAXA, detailing the Venus Climate Orbiter mission:



Further Reading: JAXA



About 

Author, freelance writer, educator, Taekwon-Do instructor, and loving hubby, son and Island boy!
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Gallery: Some Of Kepler’s Strange New Worlds Outside The Solar System

Gallery: Some Of Kepler’s Strange New Worlds Outside The Solar System:



Artist's conception of the Kepler 16 system, where the planet Kepler 16-b orbits two stars, much like Tatooine from Star Wars. Credit: NASA/JPL-Caltech/R. Hurt


Artist’s conception of the Kepler 16 system, where the planet Kepler 16-b orbits two stars, much like Tatooine from Star Wars. Credit: NASA/JPL-Caltech/R. Hurt
With the latest Kepler space telescope exoplanet finding announced yesterday, the mighty planet hunter has now found 1,000 confirmed worlds — with about 3,000 more planetary candidates just waiting for confirmation.

The NASA observatory has found exoplanets of many sizes — smaller than Mercury, the size of our Moon, the size of Jupiter or larger, and in a couple of cases, Earth-sized worlds in the habitable regions of their stars. Below is a gallery of some of the observatory’s notable finds.



An artist's conception of a planet in a star cluster. Credit: Michael Bachofner


An artist’s conception of a planet in a star cluster. Credit: Michael Bachofner


An artist's conception of one of the newly released exo-worlds, a planet orbiting an ancient planetary nebula. Credit: David A. Aguilar/CfA.


An artist’s conception of one of the newly released exo-worlds, a planet orbiting an ancient planetary nebula. Credit: David A. Aguilar/CfA.


Meet Kepler-22b, an exoplanet with an Earth-like radius in the habitable zone of its host star. Unfortunately its mass remains unknown. Image Credit: NASA


Meet Kepler-22b, an exoplanet with an Earth-like radius in the habitable zone of its host star. Unfortunately its mass remains unknown. Image Credit: NASA


NASA's Kepler mission has discovered a new planetary system that is home to the smallest planet yet found around a star like our sun, approximately 210 light-years away in the constellation Lyra. Credit: NASA/Ames/JPL-Caltech


NASA’s Kepler mission has discovered a new planetary system that is home to the smallest planet yet found around a star like our sun, approximately 210 light-years away in the constellation Lyra. Credit: NASA/Ames/JPL-Caltech


Artist's Concept of Kepler-20e, one of two Earth-sized planets found by the Kepler spacecraft. Credit: NASA/Ames/JPL-Caltech


Artist’s Concept of Kepler-20e, one of two Earth-sized planets found by the Kepler spacecraft. Credit: NASA/Ames/JPL-Caltech


Kepler-37b, a moon-sized exoplanet. Credit: NASA/Ames/JPL-Caltech


Kepler-37b, a moon-sized exoplanet. Credit: NASA/Ames/JPL-Caltech


Artist's conception of the Kepler-35 system where a Saturn-sized planet orbits its two stars. Credit: © Mark A. Garlick / space-art.co.uk


Artist’s conception of the Kepler-35 system where a Saturn-sized planet orbits its two stars. Credit: © Mark A. Garlick / space-art.co.uk


The "invisible" world Kepler-19c, seen in the foreground of this artist's conception, was discovered solely through its gravitational influence on the companion world Kepler-19b - the dot crossing the star's face. Kepler-19b is slightly more than twice the diameter of Earth, and is probably a "mini-Neptune." Nothing is known about Kepler-19c, other than that it exists. Credit: David A. Aguilar (CfA)


The “invisible” world Kepler-19c, seen in the foreground of this artist’s conception, was discovered solely through its gravitational influence on the companion world Kepler-19b – the dot crossing the star’s face. Kepler-19b is slightly more than twice the diameter of Earth, and is probably a “mini-Neptune.” Nothing is known about Kepler-19c, other than that it exists. Credit: David A. Aguilar (CfA)


Illustration of Kepler-186f, a recently-discovered, possibly Earthlike exoplanet that could be a host to life. (NASA Ames, SETI Institute, JPL-Caltech, T. Pyle)


Illustration of Kepler-186f, a recently-discovered, possibly Earthlike exoplanet that could be a host to life. (NASA Ames, SETI Institute, JPL-Caltech, T. Pyle)


About 

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.
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Here’s How You Can Help With Searching Out Planet Nurseries Beyond The Solar System

Here’s How You Can Help With Searching Out Planet Nurseries Beyond The Solar System:



With a big universe around us, where the heck do you point your telescope when looking for planets? Bigger observatories are set to head to orbit in the next decade, including NASA’s James Webb Space Telescope and the European Space Agency’s PLATO (PLAnetary Transits and Oscillations of stars). Telling them where to look will be a challenge.

But it’s less of an issue thanks to the dedicated efforts of amateurs. Volunteers sifting through data from a NASA mission called WISE (Wide-field Infrared Survey Explorer) have now classified an astounding one million potential debris disks and disks surrounding young stars.

“Combing through objects identified by WISE during its infrared survey of the entire sky, Disk Detective aims to find two types of developing planetary environments,” NASA stated in a press release touting the achievement.



Magnetic loops carry gas and dust above disks of planet-forming material circling stars, as shown in this artist's conception. These loops give off extra heat, which NASA's Spitzer Space Telescope detects as infrared light. The colors in this illustration show what an alien observer with eyes sensitive to both visible light and infrared wavelengths might see. Credit: NASA/JPL-Caltech/R. Hurt (IPAC)


Magnetic loops carry gas and dust above disks of planet-forming material circling stars, as shown in this artist’s conception. These loops give off extra heat, which NASA’s Spitzer Space Telescope detects as infrared light. The colors in this illustration show what an alien observer with eyes sensitive to both visible light and infrared wavelengths might see. Credit: NASA/JPL-Caltech/R. Hurt (IPAC)
“The first, known as a YSO disk, typically is less than 5 million years old, contains large quantities of gas, and often is found in or near young star clusters. The second planetary habitat, known as a debris disk, tends to be older than 5 million years, holds little or no gas, and possesses belts of rocky or icy debris that resemble the asteroid and Kuiper belts found in our own solar system.”

What’s more astounding is how little time it took — the program Disk Detective was only launched in January 2014. These are ripe environments in which young planets can form, providing plenty of spots for telescopes to turn their eyes. The search is expected to go on through 2018.

Want to contribute? Check out the website and see if you can help with the search!

Source: NASA



About 

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.
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Glorious Star Factories Shine In Astounding Amateur Shots

Glorious Star Factories Shine In Astounding Amateur Shots:



A colorful photo of the "Tulip Nebula" taken by Julian Hancock.


A colorful photo of the “Tulip Nebula” taken by Julian Hancock.
We often publish photos from professional observatories, but it’s important to note that amateurs can also do a great job taking pictures of the sky with modest equipment and photo processing software.

On Universe Today’s Flickr pool, we’re proud to showcase the work of all the fans of the cosmos. Included here are some of the best shots of galaxies and nebulas that we’ve seen uploaded to the site in recent days.



The Milky Way shines over Termas de Chillán in this photo taken by "Miss Andrea" on Flickr.


The Milky Way shines over Termas de Chillán in this photo taken by “Miss Andrea” on Flickr.


The center of the Heart Nebula captured by David Wills on Flickr.


The center of the Heart Nebula captured by David Wills on Flickr.


Simeis 147, the "Spaghetti Nebula", shines in hydrogen alpha in this image captured by Rick Stevenson on Flickr.


Simeis 147, the “Spaghetti Nebula”, shines in hydrogen alpha in this image captured by Rick Stevenson on Flickr.


The Tarantula Nebula imaged in Ha, OIII and SII by Alan Tough on Flickr.


The Tarantula Nebula imaged in Ha, OIII and SII by Alan Tough on Flickr.


About 

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.
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Tuesday, January 6, 2015

New Simulation Models Galaxies Like Never Before

New Simulation Models Galaxies Like Never Before:



Zooming into an EAGLE galaxy. Credit: EAGLE Project Consortium/Schaye et al.


Zooming into an EAGLE galaxy. Credit: EAGLE Project Consortium/Schaye et al.
Astronomy is, by definition, intangible. Traditional laboratory-style experiments that utilize variables and control groups are of little use to the scientists who spend their careers analyzing the intricacies our Universe. Instead, astronomers rely on simulations – robust, mathematically-driven facsimiles of the cosmos – to investigate the long-term evolution of objects like stars, black holes, and galaxies. Now, a team of European researchers has broken new ground with their development of the EAGLE project: a simulation that, due to its high level of agreement between theory and observation, can be used to probe the earliest epochs of galaxy formation, over 13 billion years ago.

The EAGLE project, which stands for Evolution and Assembly of GaLaxies and their Environments, owes much of its increased accuracy to the better modeling of galactic winds. Galactic winds are powerful streams of charged particles that “blow” out of galaxies as a result of high-energy processes like star formation, supernova explosions, and the regurgitation of material by active galactic nuclei (the supermassive black holes that lie at the heart of most galaxies). These mighty winds tend to carry gas and dust out of the galaxy, leaving less material for continued star formation and overall growth.

Previous simulations were problematic for researchers because they produced galaxies that were far older and more massive than those that astronomers see today; however, EAGLE’s simulation of strong galactic winds fixes these anomalies. By accounting for characteristic, high-speed ejections of gas and dust over time, researchers found that younger and lighter galaxies naturally emerged.

After running the simulation on two European supercomputers, the Cosmology Machine at Durham University in England and Curie in France, the researchers concluded that the EAGLE project was a success. Indeed, the galaxies produced by EAGLE look just like those that astronomers expect to see when they look to the night sky. Richard Bower, a member of the team from Durham, raved, “The universe generated by the computer is just like the real thing. There are galaxies everywhere, with all the shapes, sizes and colours I’ve seen with the world’s largest telescopes. It is incredible.”

The upshots of this new work are not limited to scientists alone; you, too, can explore the Universe with EAGLE by downloading the team’s Cosmic Universe app. Videos of the EAGLE project’s simulations are also available on the team’s website.

A paper detailing the team’s work is published in the January 1 issue of Monthly Notices of the Royal Astronomical Society. A preprint of the results is available on the ArXiv.



About 

Vanessa earned her bachelor's degree in Astronomy and Physics in 2009 from Wheaton College in Massachusetts. Her credits in astronomy include observing and analyzing eclipsing binary star systems and taking a walk on the theory side as a NSF REU intern, investigating the expansion of the Universe by analyzing its traces in observations of type 1a supernovae. In her spare time she enjoys writing about astrophysics, cosmology, biology, and medicine, making delicious vegetarian meals, taking adventures with her husband and/or Nikon D50, and saving the world.
Posted by Nelio Inacio at 8:19 AM 0 comments
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Defining Life I: What are Astrobiologists Looking For?

Defining Life I: What are Astrobiologists Looking For?:



In December, 2014 researchers in the Mars Science Laboratory Project announced that they had made the first definitive detection of organic materials on the surface of Mars. The sample was taken on May 19, 2013 from a rock that mission controllers named “Cumberland”. The Curiosity Mars rover drilled a hole 1.6 cm wide and 6.6 cm deep in the Martian rock. Powered rock from the hole was delivered to the rover’s Sample Analysis at Mars (SAM) instrument for analysis. The scientists drew their conclusions only after months of careful analysis. The identity and complexity of the organic substances remains uncertain, because they may have been altered by perchlorates that were also present in the rock, when the material was heated for analysis. The Viking Mars landers of 1976 had earlier failed to detect organic materials on Mars. Credits: NASA/Jet Propulsion Laboratory, Caltech


In December, 2014 researchers in the Mars Science Laboratory Project announced that they had made the first definitive detection of organic materials on the surface of Mars. The sample was taken on May 19, 2013 from a rock that mission controllers named “Cumberland”. The Curiosity Mars rover drilled a hole 1.6 cm wide and 6.6 cm deep in the Martian rock. Powered rock from the hole was delivered to the rover’s Sample Analysis at Mars (SAM) instrument for analysis. The scientists drew their conclusions only after months of careful analysis. The identity and complexity of the organic substances remains uncertain, because they may have been altered by perchlorates that were also present in the rock, when the material was heated for analysis. The Viking Mars landers of 1976 had earlier failed to detect organic materials on Mars.
Credits: NASA/Jet Propulsion Laboratory, Caltech
How can astrobiologists find extraterrestrial life? In everyday life, we usually don’t have any problem telling that a dog or a rosebush is a living thing and a rock isn’t. In the climatic scene of the movie ‘Europa Report’ we can tell at a glance that the multi-tentacled creature discovered swimming in the ocean of Jupiter’s moon Europa is alive, complicated, and quite possibly intelligent.



But unless something swims, walks, crawls, or slithers past the cameras of a watching spacecraft, astrobiologists face a much tougher job. They need to devise tests that will allow them to infer the presence of alien microbial life from spacecraft data. They need to be able to recognize fossil traces of past alien life. They need to be able to determine whether the atmospheres of distant planets circling other stars contain the tell-tale traces of unfamiliar forms of life. They need ways to infer the presence of life from knowledge of its properties. A definition of life would tell them what those properties are, and how to look for them. This is the first of a two part series exploring how our concept of life influences the search for extraterrestrial life.


What is it that sets living things apart? For centuries, philosophers and scientists have sought an answer. The philosopher Aristotle (384-322 BC) devoted a great deal of effort to dissecting animals and studying living things. He supposed that they had distinctive special capacities that set them apart from things that aren’t alive. Inspired by the mechanical inventions of his times, the Renaissance philosopher Rene Descartes (1596-1650) believed that living things were like clockwork machines, their special capacities deriving from the way their parts were organized.

In 1944, the physicist Erwin Schrödinger (1887-1961) wrote What is Life? In it, he proposed that the fundamental phenomena of life, including even how parents pass on their traits to their offspring, could be understood by studying the physics and chemistry of living things. Schrödinger’s book was an inspiration to the science of molecular biology.

Living organisms are made of large complicated molecules with backbones of linked carbon atoms. Molecular biologists were able to explain many of the functions of life in terms of these organic molecules and the chemical reactions they undergo when dissolved in liquid water. In 1955 James Watson and Francis Crick discovered the structure of deoxyribonucleic acid (DNA) and showed how it could be the storehouse of hereditary information passed from parent to offspring.

While all this research and theorizing has vastly increased our understanding of life, it hasn’t produced a satisfactory definition of life; a definition that would allow us to reliably distinguish things that are alive from things that aren’t. In 2012 the philosopher Edouard Mahery argued that coming up with a single definition of life was both impossible and pointless. Astrobiologists get by as best they can with definitions that are partial, and that have exceptions. Their search is conditioned by our knowledge of the specific features of life on Earth; the only life we currently know.

Here on Earth, living things are distinctive in their chemical composition. Besides carbon, the elements hydrogen, nitrogen, oxygen, phosphorus, and sulfur are particularly important to the large organic molecules that make up terrestrial life. Water is a necessary solvent. Since we don’t know for sure what else might be possible, the search for extraterrestrial life typically assumes its chemical composition will be similar to that of life on Earth.

Making use of that assumption, astrobiologists assign a high priority to the search for water on other celestial bodies. Spacecraft evidence has proven that Mars once had bodies of liquid water on its surface. Determining the history and extent of this water is a central goal of Mars exploration. Astrobiologists are excited by evidence of subsurface oceans of water on Jupiter’s moon Europa, Saturn’s moon Enceladus, and perhaps on other moons or dwarf planets. But while the presence of liquid water implies conditions appropriate for Earth-like life, it doesn’t prove that such life exists or has ever existed.



Europa


Jupiter’s icy moon Europa appears to host liquid water, an essential condition for life as we know it on Earth. Its surface is covered with a crust of water ice. The Voyager and Galileo spacecraft have provided evidence that under this icy crust, there is an ocean of saltwater, containing more liquid water than all the oceans of Earth. Europa’s interior is heated by gravitational tidal forces exerted by giant Jupiter. This heat energy may drive volcanism, hydrothermal vents, and the production of chemical energy sources that living things could make use of. Interaction between materials from Europa’s surface and the ocean environment beneath could make available carbon and other chemical elements essential for Earth-like life.
Credits: NASA/Jet Propulsion Laboratory, SETI Institute


Organic chemicals are necessary for Earth-like life, but, as for water, their presence doesn’t prove that life exists, because organic materials can also be formed by non-biological processes. In 1976, NASA’s two Viking landers were the first spacecraft to make fully successful landings on Mars. They carried an instrument; called the gas chromatograph-mass spectrometer, that tested the soil for organic molecules.


Even without life, scientists expected to find some organic materials in the Martian soil. Organic materials formed by non-biological processes are found in carbonaceous meteorites, and some of these meteorites should have fallen on Mars. They were surprised to find nothing at all. At the time, the failure to find organic molecules was considered a major blow to the possibility of life on Mars.

In 2008, NASA’s Phoenix lander discovered an explanation of why Viking didn’t detect organic molecules. If found that the Martian soil contains perchlorates. Containing oxygen and chlorine, perchlorates are oxidizing agents that can break down organic material. While perchlorates and organic molecules could coexist in Martian soil, scientists determined that heating the soil for the Viking analysis would have caused the perchlorates to destroy any organic material it contained. Martian soil might contain organic materials, after all.

At a news briefing in December 2014, NASA announced that an instrument carried on board the Curiosity Mars rover had succeeded in detected simple organic molecules on Mars for the first time. Researchers believe it is possible that the molecules detected may be breakdown products of more complex organic molecules that were broken down by perchlorates during the process of analysis.



electron micrograph of Mars meteorite


In 1996 a team of scientists lead by Dr. David McKay of NASA’s Johnson Space Center announced possible evidence of life on Mars. The evidence came from their studies of a Martian meteorite found in Antarctica, called Alan Hills 84001. The researchers found chemical and physical traces of possible life including carbonate globules that resemble terrestrial nanobacteria (electron micrograph shown) and polycyclic aromatic hydrocarbons. In terrestrial rock, the chemical traces would be considered breakdown products of bacterial life. The findings became the subject of controversy as non-biological explanations for the findings were found. Today, they are no longer regarded as definitive evidence of Martian life.
Credits: NASA Johnson Space Center


The chemical make-up of terrestrial life has also guided the search for traces of life in Martian meteorites. In 1996 a team of investigators lead by David McKay of the Johnson Space Center in Houston reported evidence that a Martian meteorite found at Alan Hills in Antarctica in 1984 contained chemical and physical evidence of past Martian life.


There have since been similar claims about other Martian meteorites. But, non-biological explanations for many of the findings have been proposed, and the whole subject has remained embroiled in controversy. Meteorites have not so far yielded the kind of evidence needed to prove the existence of extraterrestrial life beyond reasonable doubt.

Following Aristotle, most scientists prefer to define life in terms of its capacities rather than its composition. In the second installment, we will explore how our understanding of life’s capacities has influenced the search for extraterrestrial life.

References and further reading:

N. Atkinson (2009) Perchlorates and Water Make for Potential Habitable Environment on Mars, Universe Today.

S. A. Benner (2010), Defining life, Astrobiology, 10(10):1021-1030.

E. Machery (2012), Why I stopped worrying about the definition of life…and why you should as well, Synthese, 185:145-164.

L. J. Mix (2015), Defending definitions of life, Astrobiology, 15(1) posted on-line in advance of publication.

T. Reyes (2014) NASA’s Curiosity Rover detects Methane, Organics on Mars, Universe Today.

S. Tirard, M. Morange, and A. Lazcano, (2010), The definition of life: A brief history of an elusive scientific endeavor, Astrobiology, 10(10):1003-1009.

Did Viking Mars landers find life’s building blocks? Missing piece inspires new look at puzzle. Science Daily Featured Research Sept. 5, 2010

NASA rover finds active and ancient organic chemistry on Mars, Jet Propulsion laboratory, California Institute of Technology, News, Dec. 16, 2014.

Europa: Ingredients for Life?, National Aeronautics and Space Administration.



About 

Paul Patton is a freelance science writer. He holds a Bachelor's degree in physics from the University of Wisconsin Green Bay, a Master's degree in the history and philosophy of science from Indiana University, and a Doctorate in neuroscience from the University of Chicago. He has been interested in space, astronomy, and extraterrestrial life since early childhood.
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Exciting Exoplanet News from AAS: How Rocky Worlds are Made; Oceans on Super-Earths

Exciting Exoplanet News from AAS: How Rocky Worlds are Made; Oceans on Super-Earths:



This artist's depiction shows a gas giant planet rising over the horizon of an alien waterworld. New research shows that oceans on super-Earths, once established, can last for billions of years. David A. Aguilar (CfA)


This artist’s depiction shows a gas giant planet rising over the horizon of an alien waterworld. Image Credit: David A. Aguilar (CfA)
Astronomers from around the world gathered in Seattle today for the 225th meeting of the American Astronomical Society. Although it’s just past noon on the West Coast, the discoveries are already beginning to unfurl. Here are some of the highlights from this morning’s exoplanet session. And the keyword seems to be “water.”

A Recipe for Earth-like Planets?

There’s no doubt that the term “Earth-like” is a bit of a misnomer. It requires only that a planet is both Earth-size and circles its host star within the habitable zone. It says nothing about the composition of that planet.

Now, Courtney Dressing from the Harvard-Smithsonian Center for Astrophysics (CfA) and her colleagues have taken detailed observations of small exoplanets in order to nail down a digestible recipe.

Dressing and her colleagues focused on only a handful of exoplanets because they had to take painstakingly long, but accurate measurements. They used the HARPS-N instrument on the 3.6-meter Telescope in the Canary Islands to precisely determine the planets’ densities.

Most recently the team targeted Kepler-93b, a planet 1.5 times the size of Earth and 4.01 times the mass of Earth. Kepler 93-b, as well as all other exoplanets with sizes less than 1.6 times Earth’s size and six times Earth’s mass, show a tight relationship between size and mass. In other words, when plotted by size vs. mass, they fit onto the same line as Venus and the Earth, suggesting they’re all rocky planets.

Larger and more massive exoplanets do not follow the same trend. Nature simply doesn’t want to make rocky planets that are more massive than six Earth masses. Instead, their densities are significantly lower, meaning their recipes include a large fraction of water or hydrogen and helium.

“Today if you’re not too worn out from all the holiday baking, when you get back home, I’d encourage you to check out this new recipe for rocky planets” said Dressing at the AAS press conference. The playful recipe requires one cup of magnesium, one cup of silicon, two cups of iron, two cups of oxygen, ½ teaspoon aluminum, ½ teaspoon nickel, ½ teaspoon calcium, and ¼ teaspoon sulfur.

Now you have to be patient. “Bake this for a couple million years until you start to see a thin, light brown crust form on the surface of the planet,” said Dressing. Then season it with a dash of water. “If you check back in a couple million years, maybe you’ll see some intelligent life on your planet.”

Super-Earths Have Long Lasting Oceans

Another team of astronomers took a closer look at that dash of water. There’s no doubt that life, as we know it, needs liquid water. The Earth’s oceans cover about 70 percent of the surface and have for nearly the entire history of our world. So the next logical step suggests that for life to develop on other planets, those planets would also need oceans.

Water, however, isn’t just on Earth’s surface. Studies have shown that Earth’s mantle holds several oceans’ worth of water that was dragged underground. If water weren’t able to return to the surface via volcanism, it would disappear entirely.

Laura Schaefer, also from the CfA, used computer simulations to see if this so-called deep water cycle could take place on Earth-like planets and super-Earths.

She found that small Earth-like planets outgas their water quickly, while larger super-Earths form their oceans later on. The sweet spot seems to be for planets between two and four times the mass of Earth, which are even better at establishing and maintaining oceans than our Earth. Once started, these oceans could persist for at least 10 billion years.

“If you want to look for life, you should look at older super-Earths,” said Schaefer. It’s a statement that applies to both realms of research presented today.

The AAS will continue throughout the week. So stay tuned because Universe Today will continue bringing you the highlights.



About 

Shannon Hall is a freelance science journalist. She holds two B.A.'s from Whitman College in physics-astronomy and philosophy, and an M.S. in astronomy from the University of Wyoming. Currently, she is working toward a second M.S. from NYU's Science, Health and Environmental Reporting program. You can follow her on Twitter @ShannonWHall.
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Get a Change of View of Mercury’s North Pole

Get a Change of View of Mercury’s North Pole:

A forced perspective view of Profokiev crater near Mercury's north pole
A forced perspective view of Prokofiev crater near Mercury’s north pole
It’s always good to get a little change of perspective, and with this image we achieve just that: it’s a view of Mercury’s north pole projected as it might be seen from above a slightly more southerly latitude. Thanks to the MESSENGER spacecraft, with which this image was originally acquired, as well as the Arecibo Observatory here on Earth, scientists now know that these polar craters contain large deposits of water ice – which may seem surprising on an airless and searing-hot planet located so close to the Sun but not when you realize that the interiors of these craters never actually receive sunlight.

The locations of ice deposits are shown in the image in yellow. See below for a full-sized version.



Perspective view of Mercury's north pole made from MESSENGER MDIS data.


Perspective view of Mercury’s north pole made from MESSENGER MDIS images and Arecibo Observatory data. (NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington)
The five largest ice-filled craters in this view are (from front to back) the 112-km-wide Prokofiev and the smaller Kandinsky, Tolkien, Tryggvadottir, and Chesterton craters. A mosaic of many images acquired by MESSENGER’s Mercury Dual Imaging Sustem (MDIS) instrument during its time in orbit, you would never actually see a view of the planet’s pole illuminated like this in real life but orienting it this way helps put things into…well, perspective.



Radar observations from Arecibo showing bright areas on Mercury's north pole


Radar observations from Arecibo showing bright areas on Mercury’s north pole
Radar-bright regions in Mercury’s polar craters have been known about since 1992 when they were first imaged from the Arecibo Observatory in Puerto Rico. Located in areas of permanent shadow where sunlight never reaches (due to the fact that Mercury’s axial tilt is a mere 2.11º, unlike Earth’s much more pronounced 23.4º slant) they have since been confirmed by MESSENGER observations to contain frozen water and other volatile materials.

Read more: Ice Alert! Mercury’s Deposits Could Tell Us More About How Water Came To Earth

Similarly-shadowed craters on our Moon’s south pole have also been found to contain water ice, although those deposits appear different in composition, texture, and age. It’s suspected that some of Mercury’s frozen materials may have been delivered later than those found on the Moon, or are being restored via an ongoing process. Read more about these findings here.

Explore Mercury’s shadowed craters with the Water Ice Data Exploration (WIDE) app

In orbit around Mercury since 2011, MESSENGER is now nearing the end of its operational life. Engineers have figured out a way to extend its fuel use for an additional month, possibly delaying its inevitable descent until April, but even if this maneuver goes as planned the spacecraft will be meeting Mercury’s surface very soon.

Source: MESSENGER



About 

A graphic designer in Rhode Island, Jason writes about space exploration on his blog Lights In The Dark, Discovery News, and, of course, here on Universe Today. Ad astra!
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Drone Ship at Sea Preparing for Bold SpaceX Rocket Recovery Landing Attempt

Drone Ship at Sea Preparing for Bold SpaceX Rocket Recovery Landing Attempt:



SpaceX drone ship sailing at sea to hold position awaiting Falcon 9 rocket landing. Credit: Elon Musk/SpaceX


SpaceX drone ship sailing at sea to hold position awaiting Falcon 9 rocket landing. Credit: Elon Musk/SpaceX
Aiming to one day radically change the future of the rocket business, SpaceX CEO Elon Musk has a bold vision unlike any other in a historic attempt to recover and reuse rockets set for Jan. 6 with the goal of dramatically reducing the enormous costs of launching anything into space.

Towards the bold vision of rocket reusability, SpaceX dispatched the “autonomous spaceport drone ship” sailing at sea towards a point where Musk hopes it will serve as an ocean going landing platform for the first stage of his firm’s Falcon 9 rocket after it concludes its launch phase to the International Space Station (ISS).

“Drone spaceport ship heads to its hold position in the Atlantic to prepare for a rocket landing,” tweeted Musk today (Jan. 5) along with a photo of the drone ship underway (see above).

The history making and daring experimental landing is planned to take place in connection with the Tuesday, Jan. 6, liftoff of the Falcon 9 booster and Dragon cargo freighter bound for the ISS on a critical resupply mission for NASA.

No one has ever tried such a landing attempt before in the ocean says SpaceX. The company has conducted numerous successful soft landing tests on land. And several soft touchdowns on the ocean’s surface. But never before on a barge in the ocean.

The “autonomous spaceport drone ship” departed the port of Jacksonville, FL, on Saturday, heading to a point somewhere around 200 to 250 miles or so off the US East coast in a northeasterly direction coinciding with the flight path of the rocket.



SpaceX Falcon 9 first stage rocket will attempt precison landing on this autonomous spaceport drone ship soon after launch set for Dec. 19, 2014 from Cape Canaveral, Florida. Credit: SpaceX


SpaceX Falcon 9 first stage rocket will attempt precision landing on this autonomous spaceport drone ship soon after launch set for January 6, 2015, from Cape Canaveral, Florida. Credit: SpaceX
The SpaceX Dragon CRS-5 mission is slated to blast off at 6:20 am EST, Tuesday, Jan. 6, 2015, atop the SpaceX Falcon 9 rocket from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida.



Falcon 9 and Dragon have gone vertical in advance of the 6:20am ET launch on Jan. 6, 2015. Credit: SpaceX.


Falcon 9 and Dragon have gone vertical in advance of the 6:20 am ET launch on Jan. 6, 2015. Credit: SpaceX.
The absolute overriding goal of the mission is to safely deliver NASA’s contracted payload to the ISS, emphasized Hans Koenigsmann, VP of Mission Assurance, SpaceX, at a media briefing today (Jan. 5) at the Kennedy Space Center. Landing on the off shore barge is just a secondary objective of SpaceX, not NASA, he repeated several times.

The Dragon CRS-5 spacecraft is loaded with over 5108 pounds (2317 kg) of scientific experiments, technology demonstrations, crew supplies, spare parts, food, water, clothing, and assorted research gear for the six person crew serving aboard the ISS.

Koenigsmann estimated the odds of success at the landing attempt at about 50% at best according to an estimate from Musk himself.

“It’s an experiment. There’s a certain likelihood that this will not work out right, that something will go wrong.”

The two stage Falcon 9 and Dragon stands 207.8 feet (63.3 meters) tall and is 12 feet in diameter. The first stage is powered by nine Merlin 1D engines that generate 1.3 million pounds of thrust at sea level and rises to 1.5 million pounds of thrust as the Falcon 9 climbs out of the atmosphere, according to a SpaceX fact sheet.

The first stage Merlins will fire for three minutes until the planned engine shutdown and main engine cutoff known as MECO, said Koenigsmann.

The rocket will be in space at an altitude of over 100 miles zooming upwards at 1300 m/s (nearly 1 mi/s).

Then, a single Merlin 1D will be commanded to re-fire for three separate times to stabilize and lower the rocket during the barge landing attempt.

Four hypersonic grid fins had been added to the first stage and placed in an X-wing configuration. They will be deployed only during the reentry attempt and will be used to roll, pitch, and yaw the rocket in concert with gamboling of the engines.

It will take about nine minutes from launch until the first stage reaches the barge, said Koenigsmann. That’s about the same time it takes for Dragon to reach orbit.

He added that, depending on the internet connectivity, SpaceX may or may not know the outcome in real time.



Testing operation of Falcon 9 hypersonic grid fins (x-wing config) launching on next Falcon 9 flight, CRS-5. Credit: SpaceX/Elon Musk


Testing operation of Falcon 9 hypersonic grid fins (x-wing config) launching on next Falcon 9 flight, CRS-5. Credit: SpaceX/Elon Musk
Here’s a description from SpaceX:

“To help stabilize the stage and to reduce its speed, SpaceX relights the engines for a series of three burns. The first burn—the boostback burn—adjusts the impact point of the vehicle and is followed by the supersonic retro propulsion burn that, along with the drag of the atmosphere, slows the vehicle’s speed from 1300 m/s to about 250 m/s. The final burn is the landing burn, during which the legs deploy and the vehicle’s speed is further.”

“To complicate matters further, the landing site is limited in size and not entirely stationary. The autonomous spaceport drone ship is 300 by 100 feet, with wings that extend its width to 170 feet. While that may sound huge at first, to a Falcon 9 first stage coming from space, it seems very small. The legspan of the Falcon 9 first stage is about 70 feet and while the ship is equipped with powerful thrusters to help it stay in place, it is not actually anchored, so finding the bullseye becomes particularly tricky. During previous attempts, we could only expect a landing accuracy of within 10km. For this attempt, we’re targeting a landing accuracy of within 10 meters.”



SpaceX founder and CEO Elon Musk briefs reporters including Universe Today in Cocoa Beach, FL prior to SpaceX Falcon 9 rocket blastoff with SES-8 communications satellite on Dec 3, 2013 from Cape Canaveral, FL. Credit: Ken Kremer/kenkremer.com


SpaceX founder and CEO, Elon Musk, briefs reporters, including Universe Today, in Cocoa Beach, FL, prior to a previous SpaceX Falcon 9 rocket blastoff from Cape Canaveral, FL. Credit: Ken Kremer/kenkremer.com
CRS-5 marks the company’s fifth resupply mission to the ISS under a $1.6 Billion contract with NASA to deliver 20,000 kg (44,000 pounds) of cargo to the station during a dozen Dragon cargo spacecraft flights through 2016 under NASA’s Commercial Resupply Services (CRS) contract.

The cargo delivery is the entire point of the CRS-5 mission.



The official CRS-5 Mission Patch


The official CRS-5 Mission Patch
The weather odds have improved to 70% GO from 60% GO reported Major Perry Sweat, 45th Weather Squadron rep, USAF, at the briefing today at the Kennedy Space Center.

Following the catastrophic failure of the Orbital Sciences Antares rocket and Cygnus cargo freighter on Oct. 28 from NASA’s Wallops Flight Facility in Virginia, Antares launches are on hold.

Therefore the US supply train to the ISS is now wholly dependent on SpaceX.

NASA Television live launch coverage begins at 5 a.m. EST on Jan. 6 at: http://www.nasa.gov/multimedia/nasatv/

SpaceX also will webcast the launch at: http://www.spacex.com/webcast/

Stay tuned here for Ken’s continuing Earth and planetary science and human spaceflight news.

Ken Kremer



A SpaceX Falcon 9 rocket and Dragon cargo ship are set to liftoff on a resupply mission to the International Space Station (ISS) from launch pad 40 at Cape Canaveral, Florida on Jan. 6, 2015. File photo. Credit: Ken Kremer – kenkremer.com


A SpaceX Falcon 9 rocket and Dragon cargo ship are set to liftoff on a resupply mission to the International Space Station (ISS) from launch pad 40 at Cape Canaveral, Florida on Jan. 6, 2015. File photo. Credit: Ken Kremer – kenkremer.com


About 

Dr. Ken Kremer is a speaker, scientist, freelance science journalist (Princeton, NJ) and photographer whose articles, space exploration images and Mars mosaics have appeared in magazines, books, websites and calendars including Astronomy Picture of the Day, NBC, BBC, SPACE.com, Spaceflight Now and the covers of Aviation Week & Space Technology, Spaceflight and the Explorers Club magazines. Ken has presented at numerous educational institutions, civic & religious organizations, museums and astronomy clubs. Ken has reported first hand from the Kennedy Space Center, Cape Canaveral, NASA Wallops, NASA Michoud/Stennis/Langley and on over 40 launches including 8 shuttle launches. He lectures on both Human and Robotic spaceflight - www.kenkremer.com. Follow Ken on Facebook and Twitter
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