7. Planet-Star Systems

2017-03-10. New Images of Pan, Saturn's Walnut Moon, in Unprecedented Detail. By JoAnna Wendel, Earth & Space Science News, EoS (AGU).

2017-02-17. Building blocks of life found on dwarf planet Ceres. By CBC News, Thomson Reuters.

2017-01-23. Ancient Bits of Rock Help Solve an Asteroid Mystery. By Kenneth Chang, The New York Times.

2016-11-25. An Ice Sheet the Size of New Mexico Hidden in Martian Crater. By Kenneth Chang, The New York Times.

2016-09-26. NASA’s Hubble Spots Possible Water Plumes Erupting on Jupiter's Moon Europa. NASA RELEASE 16-096.

2016-08-17. Six Things Dwarf Planets Have Taught Us About the Solar System. By By JoAnna Wendel Earth & Space News EoS (AGU).

2016-07-28. Forbidden planets: Understanding alien worlds once thought impossible. By Daniel Clery, Science.

2016-06-28. NASA’s Juno Spacecraft Will Soon Be in Jupiter’s Grip. By Kenneth Chang, New York Times.

2016-05-19. Seeking Pluto’s Frigid Heart. By The New York Times.

2016-05-19. Tsunamis Splashed Ancient Mars. By Shannon Hall, EoS-Earth & Space Science News (AGU).

2016-01-20. Evidence suggests huge ninth planet exists past Pluto at solar system's edge. By Ian Sample, The Guardian.

2015-12-04 New Horizons Returns First of the Best Images of Pluto [NASA Feature]

2015-11-23. Mars to lose its largest moon, but gain a ring. By Robert Sanders, UC Berkeley News.

2015-11-12. The Dwarf Planet That Came in from the Cold—Maybe. By Ron Cowen, EoS, Earth & Space Science News, AGU.

2015-11-09. Four Months after Pluto Flyby, NASA’s New Horizons Yields Wealth of Discovery. NASA Release 15-214.

2015-10-30. Cassini samples an alien ocean. By Carolyn Gramling, Science.

2015-10-16. The Pluto system: Initial results from its exploration by New Horizons. By S. A. Stern1, F. Bagenal, et al, Science. 

2015-10-12. Enceladus’s subsurface ocean wraps the moon. By Steven K. Blau, Physics Today.

2015-09-28. Dark streaks on Mars are definitely wet, NASA says. By Eric Hand, Science.

2015-08-21. Saturn’s moon has a fluffy heart. By Nola Taylor Redd, Science.

2015 July 14. NASA's Three-Billion-Mile Journey to Pluto Reaches Historic Encounter NASA Release 15-149.

2015-06-03. NASA’s Hubble Finds Pluto’s Moons Tumbling in Absolute Chaos. NASA Release 15-111.

2015-03-12. Huge ocean confirmed underneath solar system’s largest moon. By Eric Hand, Science.

2015-03-06. NASA Spacecraft Becomes First to Orbit a Dwarf Planet. NASA RELEASE 15-034.

2015-03-05. NASA Research Suggests Mars Once Had More Water than Earth’s Arctic Ocean. NASA RELEASE 15-032.

2015-01-22. Ten new Rosetta images that reveal comet 67P in all its glory. By Eric Hand, Science.

2014-12-10. Comet Data Clears Up Debate on Earth’s Water. By Kenneth Chang, The New York Times

2014-12-08.  NASA’s Curiosity Rover Finds Clues to How Water Helped Shape Martian Landscape. NASA RELEASE 14-326.

2014-11-12. Landing on Comet, a Mission Aims to Unlock Earth’s Mysteries. By Kenneth Chang, The New York Times.

2014-09-08. Scientists Find Evidence of ‘Diving’ Tectonic Plates on Jupiter’s Moon Europa. Excerpt: Scientists have found evidence of plate tectonics on Jupiter’s moon Europa. This indicates the first sign of this type of surface-shifting geological activity on a world other than Earth. ...While examining Europa images taken by NASA’s Galileo orbiter in the early 2000s, planetary geologists Simon Kattenhorn, of the University of Idaho, Moscow, and Louise Prockter, of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, discovered some unusual geological boundaries. ...When Kattenhorn and Prockter rearranged the icy terrain in the images, they discovered about 7,700 square miles (about 20,000 square kilometers) of the surface were missing in the moon’s high northern latitudes. Further evidence suggested the missing terrain moved under a second surface plate -- a scenario commonly seen on Earth at plate-tectonic boundaries. Kattenhorn and Prockter saw ice volcanoes on the overriding plate, possibly formed through melting and absorption of the slab as it dove below the surface, and a lack of mountains at the subduction zone, implying material was pushed into the interior rather than crumpled up as the two plates mashed against each other. The scientists believe the subducted area was absorbed into Europa's ice shell, which may be up to 20 miles (about 30 kilometers) thick, rather than breaking through it into Europa's underlying ocean.  ...Previous scientific findings point to the existence of a liquid water ocean located under the moon’s icy crust. This ocean covers Europa entirely and contains more liquid water than all of Earth's oceans combined. ...For more information about Europa and images of the plate tectonics, visit: http://solarsystem.nasa.gov/europa. Information is available online about the Galileo Mission at: http://www.jpl.nasa.gov/missions/galileo .... http://www.nasa.gov/press/2014/september/scientists-find-evidence-of-diving-tectonic-plates-on-jupiter-s-moon-europa/#.VA7BmUiyPZE. By NASA RELEASE 14-241.

2014-08-28. NASA's Spitzer Telescope Witnesses Asteroid Smashup. Excerpt: NASA's Spitzer Space Telescope has spotted an eruption of dust around a young star, possibly the result of a smashup between large asteroids. This type of collision can eventually lead to the formation of planets. Scientists had been regularly tracking the star, called NGC 2547-ID8, when it surged with a huge amount of fresh dust between August 2012 and January 2013. "We think two big asteroids crashed into each other, creating a huge cloud of grains the size of very fine sand, which are now smashing themselves into smithereens and slowly leaking away from the star," said lead author and graduate student Huan Meng of the University of Arizona, Tucson. ...Rocky planets begin life as dusty material circling around young stars. The material clumps together to form asteroids that ram into each other. Although the asteroids often are destroyed, some grow over time and transform into proto-planets. After about 100 million years, the objects mature into full-grown, terrestrial planets. Our moon is thought to have formed from a giant impact between proto-Earth and a Mars-size object. ..."We not only witnessed what appears to be the wreckage of a huge smashup, but have been able to track how it is changing -- the signal is fading as the cloud destroys itself by grinding its grains down so they escape from the star," said Kate Su of the University of Arizona and co-author on the study. "Spitzer is the best telescope for monitoring stars regularly and precisely for small changes in infrared light over months and even years." ..."We are watching rocky planet formation happen right in front of us," said George Rieke, a University of Arizona co-author of the new study. "This is a unique chance to study this process in near real-time." ...The results of this study are posted online Thursday in the journal Science.... http://www.nasa.gov/press/2014/august/nasas-spitzer-telescope-witnesses-asteroid-smashup/. NASA RELEASE 14-226.

2014-08-17. Cassini Saturn mission Ten Year Top Science page: http://saturn.jpl.nasa.gov/news/cassinifeatures/10thannivdiscoveries/
Video about Cassini's future:
Infographict, By The Numbers:
Ten Year Top Images:

Top Science of 2013:
Top Images of 2013:

2014-07-28. Cassini Spacecraft Reveals 101 Geysers and more on Icy Saturn Moon. NASA RELEASE 14-203. For GSS A Changing Cosmos chapter 7. Excerpt: Scientists using mission data from NASA’s Cassini spacecraft have identified 101 distinct geysers erupting on Saturn’s icy moon Enceladus.  Their analysis suggests it is possible for liquid water to reach from the moon’s underground sea all the way to its surface. ...After the first sighting of the geysers in 2005, scientists suspected repeated flexing of Enceladus by Saturn’s tides as the moon orbits the planet had something to do with their behavior.  ...Individual geysers were found to coincide with small-scale hot spots, only a few dozen feet (or tens of meters) across, which were too small to be produced by frictional heating, but the right size to be the result of condensation of vapor on the near-surface walls of the fractures. ...“Once we had these results in hand we knew right away heat was not causing the geysers, but vice versa,” said Carolyn Porco, leader of the Cassini imaging team from the Space Science Institute in Boulder, Colorado, and lead author of the first paper. “It also told us the geysers are not a near-surface phenomenon, but have much deeper roots.” Additional details, images and an animation are available at: http://www.ciclops.org/view_event/202 More information about Cassini is available at: http://www.nasa.gov/cassini ...  http://www.nasa.gov/press/2014/july/cassini-spacecraft-reveals-101-geysers-and-more-on-icy-saturn-moon/#.U_t6YkiprZE

2014-04-24. Astronomical Forensics Uncover Planetary Disks in NASA's Hubble Archive. Excerpt: Astronomers using NASA's Hubble Space Telescope have applied a new image processing technique to obtain near-infrared scattered light photos of five disks observed around young stars in the Mikulski Archive for Space Telescopes database. These disks are telltale evidence for newly formed planets. If astronomers initially miss something in their review of data, they can make new discoveries by revisiting earlier data with new image processing techniques, thanks to the wealth of information stored in the Hubble data archive.... http://www.nasa.gov/press/2014/april/astronomical-forensics-uncover-planetary-disks-in-nasas-hubble-archive/#.U22cK8ePPAA.  NASA Release 14-114.

2014-02-24. NASA to Hold Asteroid Initiative Opportunities Forum.  For GSS A Changing Cosmos chapter 7. Excerpt: ...NASA’s Asteroid Initiative includes two separate, but related activities: the Asteroid Redirect Mission and the Asteroid Grand Challenge.  NASA is currently developing concepts for the mission, which will employ a robotic spacecraft to capture a small near-Earth asteroid, or remove a boulder from the surface of a larger asteroid, and redirect it into a stable orbit around the moon. Astronauts will travel aboard NASA's Orion spacecraft, launched on the Space Launch System rocket, to rendezvous in lunar orbit with the captured asteroid material. Once there, they will collect samples to return to Earth for study. The grand challenge is seeking the best ideas to find all asteroid threats to human populations, and to accelerate the work that NASA is already doing for planetary defense. ...NASA's asteroid initiative: http://www.nasa.gov/asteroidinitiative .... http://www.nasa.gov/press/2014/february/nasa-to-hold-asteroid-initiative-opportunities-forum/#.UxYTT16aXKw. NASA Release 14-056. 

2014-01-30. NASA-Sponsored 'Disk Detective' Lets Public Search for New Planetary Nurseries. Excerpt: NASA is inviting the public to help astronomers discover embryonic planetary systems hidden among data from the agency's Wide-field Infrared Survey Explorer (WISE) mission through a new website, DiskDetective.org. Disk Detective is NASA's largest crowdsourcing project whose primary goal is to produce publishable scientific results. ...Astronomers have used computers to search this haystack of data for planet-forming environments and narrowed the field to about a half-million sources that shine brightly in the infrared, indicating they may be "needles": dust-rich disks that are absorbing their star's light and reradiating it as heat. ...But galaxies, interstellar dust clouds, and asteroids also glow in the infrared, which stymies automated efforts to identify planetary habitats. ... the only way to know for sure is to inspect each source by eye, which poses a monumental challenge....  http://www.nasa.gov/press/2014/january/nasa-sponsored-disk-detective-lets-public-search-for-new-planetary-nurseries/#.UvEuefYujhA. NASA RELEASE 14-038.  

2014-01-22. Herschel Telescope Detects Water on Dwarf Planet.  Excerpt: Scientists using the Herschel space observatory have made the first definitive detection of water vapor on the largest and roundest object in the asteroid belt, Ceres....  http://www.nasa.gov/press/2014/january/herschel-telescope-detects-water-on-dwarf-planet/#.Uuc84PbTl9I. NASA RELEASE 14-021.

2014-01-14. Dr. Ed Lu: Protecting Earth from Asteroids - Why We May Not See Them Coming.  Excerpt: ...more than a million “near-Earth asteroids” are larger than the asteroid that struck Tunguska, Siberia, in 1908 – and about 1,000 times more powerful than the atomic bomb dropped on Hiroshima. The 1908 asteroid was only about 40 meters across, yet it destroyed an area roughly the size of the San Francisco Bay Area. Nature magazine has just reported that “the risk of similar objects hitting our planet may be ten times larger than previously thought. Hear Dr. Lu's lecture....  http://www.commonwealthclub.org/events/2014-01-14/dr-ed-lu-protecting-earth-asteroids-why-we-may-not-see-them-coming.  Public lecture at The Commonwealth Club.

2013-04-15. NASA-Funded Asteroid Tracking Sensor Passes Key Test. http://www.nasa.gov/home/hqnews/2013/apr/HQ_13-109_Asteroid_Sensor.html - NASA RELEASE: 13-109    ...An infrared sensor that could improve NASA's future detecting and tracking of asteroids and comets has passed a critical design test. The test assessed performance of the Near Earth Object Camera (NEOCam) in an environment that mimicked the temperatures and pressures of deep space. NEOCam is the cornerstone instrument for a proposed new space-based asteroid-hunting telescope. ...The sensor could be a vital component to inform plans for the agency's recently announced initiative to develop the first-ever mission to identify, capture and relocate an asteroid closer to Earth for future exploration by astronauts. ...NASA's NEOWISE is an enhancement of the Wide-field Infrared Survey Explorer, or WISE, mission that launched in December 2009. WISE scanned the entire celestial sky in infrared light twice. It captured more than 2.7 million images of objects in space, ranging from faraway galaxies to asteroids and comets close to Earth. NEOWISE completed its survey of small bodies, asteroids and comets, in our solar system. The mission's discoveries of previously unknown objects include 21 comets, more than 34,000 asteroids in the main belt between Mars and Jupiter, and 134 near-NEOs.

2012-10-25. NASA Spacecraft Sees Huge Burp At Saturn After Large Storm | NASA Release 12-375. Excerpt: ..."This temperature spike is so extreme it's almost unbelievable, especially in this part of Saturn's atmosphere, which typically is very stable," said Brigette Hesman, the study's lead author and a University of Maryland scientist who works at Goddard. "To get a temperature change of the same scale on Earth, you'd be going from the depths of winter in Fairbanks, Alaska, to the height of summer in the Mojave Desert."
...According to Hesman, the huge spike of ethylene generated at the same
time peaked with 100 times more ethylene than scientists thought
possible for Saturn…. Full release at http://www.nasa.gov/home/hqnews/2012/oct/HQ_12-375_Cassini_Burp_Energy.html

Oct. 25, 2012

2012-10-17. Great new images of Uranus from Keck Observatory. See

2012-10-02. Amazing Meteor Boomerangs Around Earth | by SpaceWatchtower. Excerpt:   For the first time ever, a meteor has grazed in and out of Earth's atmosphere, slowing enough to become a temporary satellite that lasted a full orbit. Dynamicists believe a large meteoroid broke apart as it passed over Ireland on the night of September 21, 2012. Slowed by its atmospheric passage, the object entered a temporary orbit around Earth and returned to the sky over eastern North America 155 minutes later. …Martin Goff, an officer with the Greater Manchester [England] Police, was making his rounds when he spotted a dazzling meteor at 22:55 p.m. (21:55 Universal Time). …He estimates it was about as bright as a full moon and remained visible for 35 to 40 seconds, fragmenting for at least the last half of that. "I was just flabbergasted to have seen it!"  ...Dirk Ross, who tracks bright meteors and meteorite finds worldwide, logged 564 eyewitness reports from England, Scotland, Ireland, France, Belgium, The Netherlands, and Norway.. Read the full article: http://spacewatchtower.blogspot.com/2012/10/amazing-meteor-boomerangs-around-earth.html

2012-09-20. NASA Dawn Spacecraft Sees Hydrated Minerals on Giant Asteroid  | by NASA Release 12-334. An article relevant to GSS A Changing Cosmos chapter 7. Excerpt:  WASHINGTON -- NASA's Dawn spacecraft has revealed the giant asteroid Vesta has … volatile, or easily evaporated, materials … in a broad swath around its equator. ... Pothole-like features mark some of the asteroid's surface where the volatiles boiled off. Dawn … found evidence of hydrated minerals delivered by meteorites and dust in the giant asteroid's chemistry and geology. The findings appear Thursday in the journal Science. "The source of the hydrogen within Vesta's surface appears to be hydrated minerals delivered by carbon-rich space rocks that collided with Vesta at speeds slow enough to preserve their volatile content," said Prettyman. …Scientists thought it might be possible for water ice to survive near the surface around the giant asteroid's poles. Unlike Earth's moon, however, Vesta has no permanently shadowed polar regions where ice might survive. The strongest signature for hydrogen in the latest data came from regions near the equator, where water ice is not stable….Escaping water left holes as much as six-tenths of a mile (1 kilometer) wide and as deep as 700 feet (200 meters). Seen in images from Dawn's framing camera, this pitted terrain is best preserved in sections of Marcia crater. …To view new images and for more information about Dawn, visit: http://www.nasa.gov/dawn . Read the full article: http://www.nasa.gov/home/hqnews/2012/sep/HQ_12-334_Dawn_Minerals.html

2012-05-10. NASA Dawn Spacecraft Reveals Secrets of Large Asteroid | by NASA, NASA News RELEASE: 12-153.  Excerpt: NASA's Dawn spacecraft has provided researchers with the first orbital analysis of the giant asteroid Vesta, yielding new insights into its creation and relation to the terrestrial planets and Earth's moon. Vesta now has been revealed as a special fossil of the early solar system … Vesta more closely resembles a small planet or Earth's moon than another asteroid. Results appear in today's edition of the journal Science. …Scientists now see Vesta as a layered, planetary building block with an iron core - the only one known to survive the earliest days of the solar system. The asteroid's geologic complexity can be attributed to a process that separated the asteroid into a crust, mantle and iron core with a radius of approximately 68 miles (110 kilometers) about 4.56 billion years ago. The terrestrial planets and Earth's moon formed in a similar way. …Data also confirm a distinct group of meteorites found on Earth did, as theorized, originate from Vesta. The signatures of pyroxene, an iron- and magnesium-rich mineral, in those meteorites match those of rocks on Vesta's surface. These objects account for about 6 percent of all meteorites seen falling on Earth. This makes the asteroid one of the largest single sources for Earth's meteorites. The finding also marks the first time a spacecraft has been able to visit the source of samples after they were identified on Earth… For more information about the Dawn mission, visit: http://www.nasa.gov/dawn

2012-04-25. NASA Dawn Spacecraft Reveals Secrets of Giant Asteroid Vesta.  | by NASA, RELEASE: 12-134. Excerpt: ...Findings from NASA's Dawn spacecraft reveal new details about the giant asteroid Vesta, including its varied surface composition, sharp temperature changes and clues to its internal structure. … Many of the materials seen by Dawn are composed of iron- and magnesium-rich minerals, which often are found in Earth's volcanic rocks. Images also reveal smooth pond-like deposits, which might have formed as fine dust created during impacts settled into low regions.  …Dawn obtained the highest-resolution surface temperature maps of any asteroid visited by a spacecraft. Data reveal temperatures can vary from as warm as -10 degrees Fahrenheit (-23 degrees Celsius) in the sunniest spots to as cold as -150 degrees Fahrenheit (-100 degrees Celsius) in the shadows.

2011 Dec. The curious aftermath of Neptune’s discovery.  By Deborah Kent, Physics Today, page 46. Excerpt: ...The sensational news of Neptune’s observation reached the US about a month after the initial sighting at the Berlin Observatory just after midnight on 23 September 1846. The discovery was seen as a remarkable accomplishment of celestial mechanics. Not only was Neptune just the second major planet detected in recorded history, but the planet had been mathematically predicted before it was observed.  …Neptune had been sighted before its 1846 discovery, but it had never been recognized as a major planet. In 1843 University of Cambridge graduate John Couch Adams began to pursue the idea that the well-documented orbital deviations of Uranus resulted from an unknown body, probably a planet. Astronomer Royal Airy ignored Adams’s computations. Telescope time from Cambridge Observatory director James Challis also eluded Adams, who needed observational data to confirm his prediction. In the summer of 1845, French scientist Urbain Jean Joseph LeVerrier also started to study the irregularities of the orbit of Uranus. …after a lukewarm reception from French observational astronomers, LeVerrier sent his request to Johann Galle at the Berlin Observatory. Galle agreed to look for the unknown planet, guided by LeVerrier’s prediction. Galle’s student assistant Heinrich Louis d’Arrest chose their complete copy of the detailed Berlin Academy star map for the project. According to d’Arrest, after less than an hour of observing, Galle reported “there is a star of the 8th magnitude in such and such a position, whereupon I immediately exclaimed: that star is not on the map!” The observation occurred 15 minutes after midnight on 23 September 1846. Although 19th-century contemporaries awarded the optical discovery to Galle, scholars now generally agree that Galle and d’Arrest jointly discovered the planet at the telescope in Berlin. Galle verified the initial observation the following night. The next morning he sent word to LeVerrier saying, “The planet whose position you have indicated really exists.” By 1 October, the news reached London, where it appeared in the Times. Controversy ensued. ...Traditionally, historians have credited both LeVerrier and Adams with independent mathematical predictions for the location of the planet Neptune.

2011 Dec. The formation and differentiation of Earth.  By Bernard Wood, Physics Today, page 40. Excerpt: The solar system began to form 4568 million years ago, from a disk of dust and gas around the young Sun. Within a few million years, Jupiter and Saturn had formed and the terrestrial planets had reached significant fractions of their present size. The processes by which the planets formed are of particular interest at a time when the search for Earth-like planets around other stars occupies considerable attention. Earth-like exoplanets somewhat larger than our own are already detectable, and criteria are being developed to identify stars around which smaller Earths should be present… …The planets of the solar system originated as dust and gas in the young Sun’s protoplanetary disk. The mechanisms of initial growth toward large bodies are poorly understood. But some combination of mechanical sticking and eventually gravitational perturbation must have formed many 10-km-sized objects in the first 104–105 years. At that size, gravitational perturbation becomes the dominant mechanism for further accretion through collision. Although some planetesimals would have been destroyed in collisions, others would have continued to accrete….

2011 Sep 16. Cool Video: Dawn Flies Around Vesta. Science@NASA Headline News. Excerpt: The data obtained by Dawn's framing camera will help scientists determine the processes that formed  asteroid Vesta's striking features. It will also help Dawn mission fans all over the world visualize this mysterious world, which is the second most massive object in the main asteroid belt… [Article includes link to video]

2011 August 1. Scientists Stunned by Surface of Asteroid Vesta. By The Associated Press, The New York Times. Excerpt: The first close-up pictures of the massive asteroid Vesta reveal a northern hemisphere littered with craters — including a trio nicknamed "Snowman" — and a smoother southern half, researchers reported Monday.
…The images were taken by NASA's Dawn spacecraft, which began orbiting the 330-mile-wide rocky body last month and beaming back incredible surface details that the team is only beginning to pore over. It's the first time that Vesta has been viewed up close. Until now, it has only been photographed from afar.
…Currently some 117 million miles from Earth, Vesta is the second-largest resident of the asteroid belt, a zone between Mars and Jupiter filled with hundreds of thousands of space rocks orbiting the sun. The belt formed some 4.5 billion years ago around the same time and under similar conditions as Earth and the inner planets…

2011 May 25. NASA RELEASE 11-163: NASA To Launch New Science Mission To Asteroid in 2016. Excerpt: NASA will launch a spacecraft to an asteroid in 2016 and use a robotic arm to pluck samples that could better explain our solar system's formation and how life began. The mission, called Origins-Spectral Interpretation-Resource Identification-Security-Regolith Explorer, or OSIRIS-REx, will be the first U.S. mission to carry samples from an asteroid back to Earth….
…After traveling four years, OSIRIS-REx will approach the primitive, near Earth asteroid designated 1999 RQ36 in 2020. Once within three miles of the asteroid, the spacecraft will begin six months of comprehensive surface mapping. The science team then will pick a location from where the spacecraft's arm will take a sample. The spacecraft gradually will move closer to the site, and the arm will extend to collect more than two ounces of material for return to Earth in 2023….

2011 May 9. A rare direct hit from a meteorite. By Emily Lakdawalla, The Planetary Society Blog. Excerpt: Meteorites hit Earth all the time, but they almost never score direct hits on human-built structures (or humans, for that matter). Most stories you'll read on the Web about observed meteorite falls are either wrong or hoaxes. Once in a while, though, direct hits do happen, and it looks like this recent event in Poland was the real thing….
…It happened on April 30 in a rural village called Soltmany, just after 6:00 a.m. local time. A cobble-sized rock weighing about a kilogram came down nearly vertically and smashed right through a roof:
After crashing through the roof it smashed into a concrete path and broke into several pieces…. 
…The meteorite has a nice conical shape and an obvious fusion crust, both resulting from its high-speed descent through Earth's atmosphere; tests will be needed to make sure of its extraterrestrial origin but it's got all the right qualities to be a real meteorite….

2011 May 3. NASA RELEASE 11-133: NASA Dawn Spacecraft Reaches Milestone Approaching Asteroid. Excerpt: NASA's Dawn spacecraft has reached its official approach phase to the asteroid Vesta and will begin using cameras for the first time to aid navigation for an expected July 16 orbital encounter. The large asteroid is known as a protoplanet – a celestial body that almost formed into a planet….
…Dawn's odyssey, which will take it on a 3-billion-mile journey, began on Sept. 27, 2007, with its launch from Cape Canaveral Air Force Station in Florida. It will stay in orbit around Vesta for one year. After another long cruise phase, Dawn will arrive at its second destination, an even more massive body in the asteroid belt called Ceres, in 2015….
…The mission will compare and contrast the two giant asteroids, which were shaped by different forces. Dawn's science instrument suite will measure surface composition, topography and texture. In addition, the Dawn spacecraft will measure the tug of gravity from Vesta and Ceres to learn more about their internal structures….

2009 December. From Particles to Planets. By Kathleen M. Wong, ScienceMatters@Berkeley. Excerpt: Dust, to most of us, is nothing more than a nuisance. The grayish film that collects atop bookshelves and beneath the couch is the bane of housekeepers from Arkhangelsk to Zimbabwe. But Eugene Chiang, a Berkeley professor of astronomy and earth and planetary science, says dust deserves more respect. It is, after all, the foundation upon which entire worlds are built.
A theoretical astrophysicist, Chiang studies how planetary systems form, "starting from disks of gas and micron-sized particles in orbit around young stars, and ending with congealed objects as massive as Jupiter," he says.
How dust agglomerates into something the size of a planet remains a subject of hot debate. The trick, in terms of physics, is getting started. What mechanisms could drive specks of dust to clump in the first place? One possibility is by collisions. In this scenario, dust particles carom off one another until, by chance, a few begin to stick. But as anyone who has dropped one rock atop another knows, they easily rebound, chip, or shatter.
Chiang sees a different mechanism at play. He envisions gravity gently pulling ensembles of grains together until they coalesce into giant masses. "Grains might settle towards the midplanes of disks into a thin and dense enough layer that they can self-gravitate into objects easily kilometers in size. You jump from microns to kilometers, and then you're on your way to forming even larger objects," Chiang says.
...In the 1990s, scientists discovered that magnetic fields could brake the rotation of the gas disk and allow gas to stream inward. Chiang is investigating whether this mechanism is at play in the centers of donut-hole systems.
Magnetic fields strongly influence charged particles such as electrons and ions but have no influence on uncharged materials such as wood. By considering a wide array of chemical reactions occurring within the disk, Chiang and physics graduate student Daniel Perez-Becker are calculating how much free charge exists in young solar systems, to assess the relevance of magnetic fields.
...More fully formed solar systems hold equal allure for Chiang. In 2005, Berkeley astronomers Paul Kalas and James Graham spotted a planet circling a nearby star called Fomalhaut. Images of the planet consist of little more than a few pixels of light. Even so, Chiang was still able to deduce considerable information from them....

2009 July 21. NASA images show Jupiter apparently hit by object. Pasadena, Calif. (AP) -- Astronomers say Jupiter has apparently been struck by an object, possibly a comet. Images taken by NASA early Monday show a scar in the atmosphere near the south pole of the gas giant. The images, taken by the space agency's infrared telescope in Hawaii, come on the 15th anniversary of another comet strike. In 1994, Jupiter was bombarded by pieces of the comet Shoemaker-Levy 9. Scientists at NASA's Jet Propulsion Laboratory in Pasadena captured the new images after receiving a tip from an amateur astronomer the night before. See also:
Amateur Finds New Earth-Sized Blot on Jupiter - NASA has confirmed the discovery of a new "scar" the size of the Earth in Jupiter's atmosphere, apparently showing that the planet was hit by something large in recent days.
NASA RELEASE: 09-176. Hubble Space Telescope Captures Rare Jupiter Collision. - NASA's Hubble Space Telescope has taken the sharpest visible-light picture yet of atmospheric debris from an object that collided with Jupiter on July 19.

2009 April. Journey to Jupiter. National Geographic video -- naked science series. Ganymede has a molten core.

2009 January 16. A Better View of the Planets. By Kathleen M. Wong, ScienceMatters@Berkeley, Volume 6, Issue 40. Excerpt: What's the weather like on Jupiter? Berkeley professor of astronomy Imke de Pater knows. De Pater and her colleagues have tracked the planet's titanic and long-lasting storms, observed its icy ammonia clouds, and mapped the structure of its violent atmosphere. In other work, they've discovered methane drizzle on Saturn's moon Titan, modeled Jupiter's magnetic fields, and revealed the dynamic behavior of Neptune's skies.
...Most astronomers use ground-based telescopes to study the skies. But the drawback of viewing the cosmos from Earth is the turbulence in our atmosphere. True to her innovative style, de Pater has been pushing the limits of a newer technique known as adaptive optics (AO) to improve the quality of ground-based observations.
The method uses a reference light source near the target, such as a laser beam or adjacent moon, or in some cases the object of interest itself to quantify the degree of atmospheric turbulence, and correct the data online with help of a deformable mirror. The result: a crisp and astonishingly detailed picture.
..."If you look through a conventional telescope, you can just barely see the rings around Uranus, and you certainly don't see atmospheric details," de Pater says. By contrast, the details in her AO images of the planet rival the shots sent back by the Voyager spacecraft during its 1986 Uranus flyby....

2008 October 16. Shocking start for the solar system By Stephen G. Benka. Excerpt: In the 1970s, the hypothesis arose that our solar system was formed by a passing shock wave from a supernova, which triggered the collapse of an interstellar cloud into a dense region of gas and dust that further contracted to become the Sun and its orbiting planets. The original evidence came from very old meteorites that contained magnesium-26, a daughter product of the short-lived radioactive isotope (SLRI) aluminum-26-produced in stellar nucleosynthesis. Further evidence came from another SLRI, nickel-60, which can only be produced in a supernova's furnace. In astronomical terms, short-lived means a half-life of about a million years; any SLRIs would have been transported to, and dropped off in, the pre-solar cloud faster than that time scale. Computer modelers from the late 1990s, however, could not produce both the collapse and the injection of supernova material unless they artificially prevented the shock wave from heating the cloud. That situation has now been remedied by a group from the Carnegie Institution of Washington, who used a modern, adaptive-grid computer code with an improved treatment of heating and cooling. Their new models show that a supernova's shock wave moving into an otherwise stable solar-mass cloud can both trigger the collapse and leave behind enriched gas and dust, including the SLRIs whose products are found in meteorites. Furthermore, the researchers found that a protostar began to form in less than 200?000 years, in the blink of an astronomical eye. (A. P. Boss et al., Astrophys. J. Lett. 686, L119, 2008.)

2008 June 17. A Bounty of Midsize Planets is Reported. By Dennis Overbye, The New York Times. Excerpt: There is a lot of new territory out there in the cosmos, but nothing you would want to pitch camp on — yet.
About a third of all the Sun-like stars in our galaxy harbor modestly sized planets, according to a study announced Monday by a team of European astronomers.
At a meeting in Nantes, France, Michel Mayor of the Geneva Observatory and his group presented a list of 45 new planets, ranging in mass from slightly bigger than Earth to about twice as massive as Neptune, from a continuing survey of some 200 stars.
All of the planets orbit their stars in 50 days or less, well within the corresponding orbit of Mercury, which takes 88 days to go around the Sun, and well within frying distance of any lifelike creatures.
Dr. Mayor called the discoveries "only the tip of the iceberg" in a news release from the European Southern Observatory in Garching, Germany.
About one in 14 stars harbors a massive giant planet like Jupiter or Saturn, Dr. Mayor estimated. If in fact one in three harbors a Neptune or super-Earth, that is an appealing situation for astronomers and others who would like someday to find someplace livable or even someone living Out There...

  Articles from 2008–present

Asteroid visualization
(YouTube) - an animation of the solar system showing asteroid discoveries starting in 1980. Earth Crossers are Red. Earth Approachers (Perihelion less than 1.3AU) are Yellow. All Others are Green.