{"id":39943,"date":"2012-12-28T18:38:55","date_gmt":"2012-12-28T10:38:55","guid":{"rendered":"https:\/\/wp-productionenv-bjg9h2g2bgg5b8aa.southeastasia-01.azurewebsites.net\/news\/year-in-review-part-ii-through-the-solar-system-and-beyond\/"},"modified":"2012-12-28T18:38:55","modified_gmt":"2012-12-28T10:38:55","slug":"year-in-review-part-ii-through-the-solar-system-and-beyond","status":"publish","type":"post","link":"https:\/\/starpath.global\/news\/year-in-review-part-ii-through-the-solar-system-and-beyond\/","title":{"rendered":"Year in review (Part II) \u2013 Through the solar system and beyond"},"content":{"rendered":"<p>For NASA\u2019s unmanned explorers, 2012 was an astonishing year filled with discoveries and observations inside our solar system, at the outer reaches of our solar system, and in the star systems beyond our own. Leading these discoveries were the NASA probes MESSENGER, GRAIL, Cassini, Voyager I, and the Kepler Space Telescope.<\/p>\n<\/p>\n<p>MESSENGER at Mercury \u2013 Water on the inner-most planet:<\/p>\n<p>Beginning 2012 with a mission extension to March 2013, NASA\u2019s MESSENGER spacecraft in orbit of Mercury offered one of the most exciting missions of the 2012 year.<\/p>\n<p><img fetchpriority=\"high\" decoding=\"async\" class=\"alignleft size-full wp-image-27499\" title=\"NASA MESSENGER Arriving at Mercury\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z32.jpg\" alt=\"NASA MESSENGER Arriving at Mercury\" width=\"353\" height=\"236\" srcset=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z32.jpg 353w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z32-350x234.jpg 350w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z32-263x175.jpg 263w\" sizes=\"(max-width: 353px) 100vw, 353px\">Beginning the year with a series of orbital adjustments, the MESSENGER spacecraft successfully completed its first orbit correction maneuver on 2 March to bring its periapsis (time of closest approach to Mercury\u2019s surface) from 400 kilometers to just 200 km.<\/p>\n<p>Inserted into a highly eccentric orbit around Mercury, MESSENGER\u2019s original orbit took it from 400 km above Mercury\u2019s surface to 15,200 kilometers altitude every 12 hours.<\/p>\n<p>The maneuver on 2 March lasted 171 seconds and used all four of the medium-sized monopropellant thrusters on the deck opposite most of the science instruments. The maneuver was completed while MESSENGER was 148 million km from Earth.<\/p>\n<p>The lowering of MESSENGER\u2019s orbit was conducted over a series of three burn operations on 2 March, 16 April, and 20 April to reduce the spacecraft\u2019s orbital rate from 12 hours to just eight hours \u2013 providing 50 percent more low altitude observation opportunities of Mercury\u2019s northern polar regions, including the region\u2019s permanently shadowed craters.<\/p>\n<p>Also occur<img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-27498\" title=\"NASA MESSENGER\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z211.jpg\" alt=\"NASA MESSENGER\" width=\"352\" height=\"255\" srcset=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z211.jpg 352w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z211-350x254.jpg 350w\" sizes=\"(max-width: 352px) 100vw, 352px\">ring in March was the release of the first full Mercury solar day data that was gathered by MESSENGER during the spacecraft\u2019s third through sixth month in orbit.<\/p>\n<p>Data gathered by the spacecraft during this time revealed many aspects of Mercury\u2019s unique characteristics, including its global magnetic field, the dynamics of its exosphere, its surface composition, its geological evolution, and its interior structure.<\/p>\n<p>Data of this magnitude and precision had never before been recorded about the inner-most planet in our solar system.<\/p>\n<p>As mission Principal Investigator Sean Solomon stated, \u201cMercury has presented us with many mysteries to date, and solving those mysteries will take new ideas and new analyses from throughout the scientific community.\u201d<\/p>\n<p>And the unlocking of Mercury\u2019s secrets kept coming. After compiling the first year\u2019s-worth of data from MESSENGER, many interesting observations regarding Mercury\u2019s landscape, its inner core, and polar shadowed regions were announced on 21 March.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-27500\" title=\"Z4\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z48.jpg\" alt=\"\" width=\"352\" height=\"268\" srcset=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z48.jpg 352w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z48-350x266.jpg 350w\" sizes=\"(max-width: 352px) 100vw, 352px\">A surprising find from these initial observations was the discovery that the interior of the Caloris impact basin, a basin that is 1,500 km wide, has a surface floor that stands higher than the impact basin\u2019s rim.<\/p>\n<p>As related by project scientist Maria Zerber, \u201cThe elevated portion of the floor of Caloris appears to be part of a quasi-linear rise that extends for approximately half the planetary circumference at mid-latitudes. Collectively, these features imply that long wavelength changes to Mercury\u2019s topography occurred after the earliest phases of the planet\u2019s geological history.\u201d<\/p>\n<p>But perhaps even more surprising was the information gathered from the first precise model of Mercury\u2019s gravity field, which, when combined with the topographic data and earlier information regarding the planet\u2019s spin state, shed light on the planet\u2019s internal structure, the thickness of its crust, the size and state of its core, and its tectonic and thermal history.<\/p>\n<h4 class=\"widget-title penci-border-arrow\">See Also<\/h4>\n<ul>\n<li>Robotic Mission Forum<\/li>\n<li>L2 Historical Section<\/li>\n<li>Click here to Join L2<\/li>\n<\/ul>\n<p>From this data came the discovery that Mercury\u2019s core is 85 percent of its planetary radius, which was even larger than previous estimates and is unusual for a planet of Mercury\u2019s small size.<\/p>\n<p>Moreover, it was discovered that parts of Mercury\u2019s core are at least still partially liquid, defying previously held beliefs that Mercury\u2019s sufficiently small size would have caused its interior to cool to the point where the core would be completely solid.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-medium wp-image-27502\" title=\"MESSENGER view of Mercury\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z76-350x233.jpg\" alt=\"MESSENGER view of Mercury\" width=\"350\" height=\"233\" srcset=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z76-350x233.jpg 350w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z76-263x175.jpg 263w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z76.jpg 360w\" sizes=\"(max-width: 350px) 100vw, 350px\">Discovery of the partially molten core state of Mercury\u2019s interior was gained through subtle dynamical motions measured from Earth-based radar and combined with parameters of the gravity field as observed by MESSENGER.<\/p>\n<p>Based on these new observations, it is now believed that Mercury has a solid silicate crust and mantle overlying a solid, iron sulfide outer core layer, a deep liquid core layer, and possibly a solid inner core \u2013 all of which will have implications for our understanding of how Mercury\u2019s magnetic field is generated and how the planet evolved from a thermal perspective.<\/p>\n<p>Also revealed in March was information regarding previously observed radar-bright features \u2013 thought to consist predominantly of frozen water ice \u2013 in Mercury\u2019s polar regions.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-27503\" class=\"size-full wp-image-27503\" title=\"Z8\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z84.jpg\" alt=\"Water Ice Potential\" width=\"349\" height=\"258\"><\/p>\n<p id=\"caption-attachment-27503\" class=\"wp-caption-text\">Water Ice Potential<\/p>\n<p>Information from MESSENGER\u2019s first full Earth-year in orbit of Mercury confirmed that these radar bright features were located in areas of permanent shadow in Mercury\u2019s southern polar region and that the deposits were also present in shadowed regions in the northern polar regions of the planet.<\/p>\n<p>However, MESSENGER, in its initial year, was not able to confirm whether or not these deposits were in fact water ice.<\/p>\n<p>By mid-year, MESSENGER scientists were able to observe waves at the boundary of Mercury\u2019s magnetosphere, leading to the conclusion that waves driven by the Kelvin-Helmholtz (KH) instability play a key role in driving Mercury\u2019s magnetosphere.<\/p>\n<p>KH waves can develop at boundaries between two media that are in relative motion to one another. In space plasmas, such waves can transfer mass and energy across the boundary between two otherwise separated regions.<\/p>\n<p>For Mercury, this boundary is between the relatively dense and fast streaming solar wind and the more rarefied magnetosphere of the planet.<\/p>\n<p>Long-term observation of these waves at Mercury mean that the KH waves develop more readily and are much more important for mass and energy transfer from the solar wind into the magnetosphere than had previously been believed.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-medium wp-image-27504\" title=\"Z9\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z92-350x258.jpg\" alt=\"\" width=\"350\" height=\"258\">And the discoveries were not over yet. By 21 September, information from MESSENGER\u2019s X-ray Spectrometer revealed a chemical diversity in Mercury\u2019s surface that was previously unknown.<\/p>\n<p>Based on findings from MESSENGER it is now understood that Mercury\u2019s volcanic, smooth plains differ in composition from the older surrounding terrain. The older terrain contains higher ratios of magnesium to silicon, sulfur to silicon, and calcium to silicon, while containing lower ratios of aluminum to silicon.<\/p>\n<p>These different compositions suggests that the smooth plains material erupted from a magma source on the planet that was chemically different from the source of the material in the older regions, shedding new light on the complex and unique geological history of Mercury.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-medium wp-image-27505\" title=\"NASA MESSENGER tectonic landforms \" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z102-350x231.jpg\" alt=\"NASA MESSENGER tectonic landforms \" width=\"350\" height=\"231\">Furthering the discoveries about Mercury\u2019s surface, by 15 November, MESSENGER scientists had discovered assemblages of tectonic landforms unlike any other previously found on Mercury or anywhere else in the solar system.<\/p>\n<p>These land formations are believed to have formed by faulting in response to horizontal contraction or shortening as the planet\u2019s interior cooled and the surface area shrank, causing blocks of crustal material to be pushed together and form unique land surface features.<\/p>\n<p>But the biggest discovery of all came in late-November of this year when NASA\u2019s scientists reported that MESSENGER had, via its neutron spectrometer, confirmed evidence for the presence of both water ice and organic compounds in the permanently shadowed craters of Mercury\u2019s north pole.<\/p>\n<p>There is water ice on one of the most inhospitable hunks of rock in the solar system \u2013 a rock located a mere 57.9 million kilometers (average distance) from the sun.<\/p>\n<p>Ebb and Flow \u2013 GRAIL categorizes the lunar gravity field:<\/p>\n<p>Beginning 2012 with one of the spacecraft in lunar orbit (orbit achieved 31 December 2011) and the second one entering orbit of the moon on 1 January 2012, NASA\u2019s GRAIL spacecraft began the science and data collection phase of their multi-month mission on 27 March 2012.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-27506\" title=\"GRAIL mission\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/W51.jpg\" alt=\"GRAIL mission\" width=\"347\" height=\"284\">An ambitious and unique mission, GRAIL utilized two identical spacecraft, named Ebb and Flow, to create the most precise map of the lunar gravity field to date.<\/p>\n<p>Mapping of the lunar gravity field was accomplished by flying the two spacecraft in precise formation using radio signals bouncing back and forth between the two spacecraft to accurately measure and define the distance between them.<\/p>\n<p>As the two spacecraft flew over areas of greater or lesser gravity, the distance between the two spacecraft changed slightly, changes that were recorded by the radio signals between the two spacecraft.<\/p>\n<p>After eight months of data collection, the most accurate lunar gravity map was compiled by NASA and released to the general public.<\/p>\n<p>Just shy of one year after entering lunar orbit, on 17 December 2012, the GRAIL spacecraft were sent into a collision course with the moon\u2019s surface, thus ending their mission.<\/p>\n<p>The impact location for Ebb and Flow was named in honor of American space icon and former shuttle astronaut Sally K. Ride who passed away earlier in the year after a long battle with cancer.<\/p>\n<p>Cassini at Saturn \u2013 an incredible legacy continues:<\/p>\n<p>To say that the Cassini mission to Saturn has been nothing short of marvelous would be an understatement. Marking its eighth year of operations at Saturn in July 2012, the Cassini orbiter spent the year cataloging new discoveries and new dynamics of the Saturnian system.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-medium wp-image-27507\" title=\"Cassini at Saturn\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z112-350x257.jpg\" alt=\"Cassini at Saturn\" width=\"350\" height=\"257\">From early in the year, Cassini\u2019s focus on Titan revealed new information about the weather patterns of the moon.<\/p>\n<p>Stemming from a new analysis of radar data, information about the Titan\u2019s climactic and geological history was gained via observation of dune fields, the second-most dominant land formation on Titan.<\/p>\n<p>The dune fields in question are significantly larger than those found on Earth, averaging 1.2 miles in width, hundreds of miles in length, and 300 feet or more in height.<\/p>\n<p>Radar data from Cassini allowed scientists to discover that the sizes of the dunes on Titan are controlled by at least two factors: altitude and latitude.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-27508\" title=\"Titan Sand Dunes\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z131.jpg\" alt=\"Titan Sand Dunes\" width=\"348\" height=\"209\">In terms of altitude, it was discovered that the more elevated dunes tended to be thinner and more widely separated than dunes at lower elevations.<\/p>\n<p>This discovery allowed scientists to postulate that the sand on the surface of Titan is not made of silicates as it is on Earth but of solid hydrocarbons precipitated out of the atmosphere.<\/p>\n<p>For the latitudinal effect on the sand dunes, it was observed the Titan\u2019s dunes were confined to the moon\u2019s equatorial region.<\/p>\n<p>As stated by project scientist Alice Le Gall, \u201cUnderstanding how the dunes form as well as explaining their shape, size, and distribution on Titan\u2019s surface is of great importance to understanding Titan\u2019s climate and geology because the dunes are a significant atmosphere-to-surface exchange interface.\u201d<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-medium wp-image-27509\" title=\"Cassini Dione\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z142-350x242.jpg\" alt=\"Cassini Dione\" width=\"350\" height=\"242\">Following this discovery came the announcement on 2 March that Cassini had detected molecular oxygen ions around the icy moon Dione, confirming the presence of a very tenuous atmosphere on the Saturnian moon.<\/p>\n<p>At Dione\u2019s surface, its atmosphere is as dense as Earth\u2019s atmosphere is 300 miles above the surface.<\/p>\n<p>Thus, Dione\u2019s atmosphere is technically an exosphere.<\/p>\n<p>The oxygen in Dione\u2019s atmosphere is believed to derive from either solar photons or energetic particles from space that bombard the moon\u2019s water ice surface and liberate oxygen molecules.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-27510\" title=\"Z15\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z151.jpg\" alt=\"\" width=\"350\" height=\"245\">Later in March, Cassini returned evidence that stress fractures on the moon Enceladus are caused by the moon\u2019s interaction with Saturn.<\/p>\n<p>This information allowed scientists to correlate the icy jets of water vapor from fissures on Enceladus\u2019s surface with the way Saturn\u2019s gravity stresses and stretches the fissures.<\/p>\n<p>The observations of the stress fissures provided more evidence for a large, subterranean body of liquid water that would be necessary to allow Enceladus to flex enough to generate stress great enough to deform the surface of the moon.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-27511\" title=\"Titan and a mudflat in Namibia\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z161.jpg\" alt=\"Titan and a mudflat in Namibia\" width=\"348\" height=\"205\">By late April, Cassini had returned evidence that revealed a striking similarity between a lake on Titan and a mudflat in Namibia.<\/p>\n<p>The new evidence from Cassini revealed that the lake on Titan could in fact be a depression that drains and refills from below its surface and not be completely filled with liquid hydrocarbons as originally thought.<\/p>\n<p>This would correspond to the way that the Etosha salt pan on Earth fills from a shallow layer of groundwater that rises during the rainy season and then drains and leaves sediment-like tidemarks showing the previous extent of the water level.<\/p>\n<p>According to project scientist Nicolas Altobelli from the European Space Agency, \u201cThese results emphasize the importance of comparative planetology and modern planetary sciences: finding familiar geological features on alien worlds like Titan allows us to test the theories explaining their formation\u201d as we see them on Earth.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-27513\" title=\"Saturn F-Ring\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z171.jpg\" alt=\"Saturn F-Ring\" width=\"348\" height=\"228\">Also in April, Cassini aided scientists in their understanding of how the F ring of Saturn behaves.<\/p>\n<p>Previously, abnormalities had been seen in the behavior of the F ring. This, thanks to new information from Cassini, is now understood to be caused in part by strange, half-mile sized objects punching through part of the F ring, leaving glittering trails behind them.<\/p>\n<p>The small objects appear to collide with the F ring at gentle speeds in collisions that drag glittering ice particles out of the ring with them, leaving a trail 20 to 100 miles long.<\/p>\n<p>The information from Cassini revealed that these objects are in part responsible for the eddies that ripple around the ring \u2013 thus aiding the understanding of how these eddies are formed.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-medium wp-image-27514\" title=\"Cassini\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z18-350x221.jpg\" alt=\"Cassini\" width=\"350\" height=\"221\">Furthermore, Cassini returned even more evidence in April regarding another of Saturn\u2019s prominent features, its moon Phoebe.<\/p>\n<p>During recent observations, Phoebe was found to be more planet-like than originally thought. Based on Cassini observations, it is now believed that Phoebe is a planetesimal whose development was arrested billions of years ago and that the moon is actually a Kuiper Belt Object, the same region where Pluto currently resides.<\/p>\n<p>By late June, attention turned back to the moon Titan when information from the Cassini spacecraft revealed that the moon likely harbors a layer of liquid water under its icy surface.<\/p>\n<p>During several observational periods, Cassini witnessed a large amount of squeezing and stretching as Titan orbited Saturn. These observations led scientists to determine that if Titan were composed entirely of stiff rock, the gravitational attraction of Saturn would cause bulges, or solid tides, on the moon of only 3 feet in height.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-27515\" title=\"Cassini Titan\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z19.jpg\" alt=\"Cassini Titan\" width=\"350\" height=\"229\">However, Cassini witnessed tides of approximately 30 feet in height, suggesting that Titan is not made entirely of solid rocky material.<\/p>\n<p>Using this information, scientists concluded that a liquid layer must exists below the moon\u2019s surface and act as the main cause for the tidal bulging observed by Cassini. Furthermore, this subterranean liquid layer would most likely be composed of water because Titan\u2019s surface is composed mainly of water ice.<\/p>\n<p>While the discovery is important from a potential life perspective, scientists were quick to point out that a subterranean water layer does not have to be huge or deep to create the amount of tidal bulging observed on Titan.<\/p>\n<p>Currently, Cassini\u2019s mission is slated to last well into the year 2017 based on current funding levels \u2013 ensuring at least five more years of exploration of the Saturnian system.<\/p>\n<p>Voyager 1 \u2013 the outskirts of the solar system:<\/p>\n<p>For over a year now, NASA has stated that Voyager 1 could exit the solar system at \u201cany moment.\u201d<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-medium wp-image-27516\" title=\"Voyager's escape\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/A20-350x265.jpg\" alt=\"Voyager's escape\" width=\"350\" height=\"265\">This year, hopes were high that Voyager 1 would actually do just that \u2013 exit the solar system and become the first human object to escape the sun\u2019s direct sphere of influence.<\/p>\n<p>But it was not meant to be in 2012.<\/p>\n<p>On 14 June, NASA issued a press release stating that Voyager 1 had encountered a region in space where the intensity of charged particles from beyond our solar system had markedly increased.<\/p>\n<p>This marked increase is one of three points of data which must make significant swings in order to indicate that a new era of space exploration has begun.<\/p>\n<p>In particular, the second measurement that would indicate Voyager 1\u2019s exit from the solar system and entry into interstellar space would be the rapid decline of energetic particles generated by the sun.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-27517\" title=\"Voyager's instruments\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/A911.jpg\" alt=\"Voyager's instruments\" width=\"349\" height=\"268\">While Voyager 1\u2019s instruments have shown a steady decline in the amount of energetic particles streaming away from the sun, the amount of particles still affecting Voyager 1 had not, as of 14 June, dropped off in any significant amount.<\/p>\n<p>Lastly, the third dataset relates to the direction of the magnetic field lines surrounding Voyager 1.<\/p>\n<p>As long as Voyager 1 is contained within the heliosphere, these magnetic field lines will run east to west in relation to the spacecraft. As soon as Voyager 1 crosses the boundary into interstellar space, scientists believe these magnetic field lines will orient into a more north-south direction relative to the spacecraft\u2019s axis.<\/p>\n<p>And by August, the second of these key indicators changed!<\/p>\n<p>With an ever-increasing rate of change, Voyager 1\u2019s cosmic ray instrument showed that on 28 July the level of high-energy cosmic rays originating from outside of the solar system jumped by an impressive 5 percent at the same time that the low-energy particles originating from inside the solar system drop by half.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-medium wp-image-27518\" title=\"Voyager 1 location\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z20-350x244.jpg\" alt=\"Voyager 1 location\" width=\"350\" height=\"244\">While fluctuations followed, and several conditions returned to previous levels in the following days, the turbulent nature of the outer solar system and the dramatic jump in high-energy cosmic rays from outside the solar system coupled with the drop of low-energy particles from inside the solar system firmly placed Voyager 1 closer to its inevitable moment of crossing out the solar system.<\/p>\n<p>Then, in late November, came word that NASA was to hold a press conference about the Voyager 1 spacecraft, fueling speculation that the craft had indeed finally passed out of the solar system.<\/p>\n<p>But as with all of the expectations before, a different surprise came on 3 December \u2013 the announcement of the discovery of a new region at the outer reaches of the solar system.<\/p>\n<p>This new region, called the magnetic highway, was discovered by Voyager 1 and was found to contain charged particles where the sun\u2019s magnetic field lines are connected to the interstellar magnetic field lines.<\/p>\n<p>The connection allows lower-energy charged particles that originate from inside our heliosphere \u2013 or bubble of charged particles the sun emits around itself \u2013 to escape the solar system while at the same time allowing higher-energy particles from outside the solar system to stream in.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-full wp-image-27519\" title=\"Voyager Spacecraft\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/A64.jpg\" alt=\"Voyager Spacecraft\" width=\"350\" height=\"254\">In essence, Voyager 1 will spend the remaining days of 2012 as it has its entire life \u2013 safely contained within the solar system.<\/p>\n<p>But that historic day is coming when Voyager 1 will exit the solar system.<\/p>\n<p>As related by project scientist Edward Stone, \u201cWe believe this is the last leg of our journey to interstellar space. Our best guess is it\u2019s likely just a few months to a couple years away. The new region isn\u2019t what we expected, but we\u2019ve come to expect the unexpected from Voyager.\u201d<\/p>\n<p>Beyond the solar system \u2013 the quest to find exoplanets:<\/p>\n<p>In terms of unmanned exploration, 2012 saw the continued pursuit to find planets outside of our own solar system.<\/p>\n<p>In 2012, an impressive 95 planets were confirmed to be orbiting stars other than the sun, including one in our galactic next-door-neighbor\u2019s house.<\/p>\n<p>The discovery of a planet in the Alpha Centauri system, a system located just 4.3 light years from Earth, was announced on 16 October.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-medium wp-image-27520\" title=\"Alpha Centauri B b\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z212-350x236.jpg\" alt=\"Alpha Centauri B b\" width=\"350\" height=\"236\">The planet, called Alpha Centauri B b, is the smallest-mass terrestrial planet yet discovered via the radial velocity detection technique.<\/p>\n<p>At approximately 1.13 times the mass of Earth, it is the lightest exoplanet ever discovered around a star similar to that of the sun and is also the closest exoplanet discovered to our own solar system.<\/p>\n<p>Using data compiled over a four-year period, European astronomers discovered a tiny but very real radial velocity signal coming from the Alpha Centauri B star every 3.2 days.<\/p>\n<p>Radial velocity is an exoplanet detection method that measures very small wobbles in the motion of the star created by the gravitational pull of an orbiting planet. The effect is extremely minute, and in the case of Alpha Centauri B, only caused the star to move back and forth by no more than 51 centimeters per seconds.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignleft size-medium wp-image-27521\" title=\"Alpha Centauri B\" src=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z66-350x233.jpg\" alt=\"\" width=\"350\" height=\"233\" srcset=\"https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z66-350x233.jpg 350w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z66-263x175.jpg 263w, https:\/\/www.nasaspaceflight.com\/wp-content\/uploads\/2012\/12\/Z66.jpg 360w\" sizes=\"(max-width: 350px) 100vw, 350px\">Astronomers were able to see a 51 centimeter per second wobble in a star located 25,666,079,113,090 miles away.<\/p>\n<p>The newly discovered planet orbits its host star every 3.236 days at a distance of approximately 6 million kilometers, ten times closer to its star than Mercury\u2019s average distance is to the sun.<\/p>\n<p>Given that Alpha Centauri B is a sun-like star, the new planet\u2019s proximity to the star rules out any chance of it being habitable to human life.<\/p>\n<p>The surface temperature of the planet is estimated to be approximately 1200 degrees C, far too hot for liquid water and above the melting temperatures of many silicate magmas. For comparison, the surface temperature of the planet Venus, the hottest planet in our solar system, is 462 degrees C.<\/p>\n<p>Nevertheless, the detection of an Earth-sized planet in the closest star system to our own is a huge advancement in the search for exoplanets.<\/p>\n<p>At the end of 2012, combining information from NASA\u2019s Kepler Space Telescope, 817 planets have been confirmed around 642 stars, and there are 2,320 Kepler planetary candidates awaiting confirmation.<\/p>\n<p>(Images via NASA, JPL, PHL and ESA).<\/p>\n","protected":false},"excerpt":{"rendered":"<p>For NASA\u2019s unmanned explorers, 2012 was an astonishing year filled with discoveries and observations inside our solar system, at the outer reaches of our solar system, and in the star systems beyond our own. Leading these discoveries were the NASA probes MESSENGER, GRAIL, Cassini, Voyager I, and the Kepler Space Telescope. MESSENGER at Mercury \u2013 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":30377,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":"","_links_to":"","_links_to_target":""},"categories":[2],"tags":[9120,9121,2826,4070,3110],"class_list":["post-39943","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-news","tag-cassni","tag-grail","tag-kepler","tag-messenger","tag-voyager"],"acf":[],"_links":{"self":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/39943"}],"collection":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/comments?post=39943"}],"version-history":[{"count":0,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/posts\/39943\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media\/30377"}],"wp:attachment":[{"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/media?parent=39943"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/categories?post=39943"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/starpath.global\/blog\/wp-json\/wp\/v2\/tags?post=39943"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}