Astro Blog

https://www.technologyreview.com/s/613060/theres-probably-another-planet-in-our-solar-system/ Source:   By MIT Technology Review. Excerpt: When it comes to exploring the solar system, astronomers have an embarrassing secret. Despite 400 years of stargazing, they have discovered only two large objects that would have been unknown to the ancients: Uranus in 1781 and Neptune in 1846. That’s not for lack of trying. The possibility of an unknown planet just beyond observational reach has attracted astronomers like moths to a flame. A few have been successful. Several astronomers together discovered Neptune after noticing that the other planets were being gravitationally nudged by an unknown mass. Neptune didn’t entirely resolve these discrepancies, and the hunt continued into the 20th century, culminating in Pluto’s discovery in 1930. But Pluto turned out to be so small that it couldn’t account for the nudging. Indeed, it was later humiliatingly demoted to a “dwarf planet.” ... ...

https://www.washingtonpost.com/news/speaking-of-science/wp/2018/05/07/yes-pluto-is-a-planet/ Source:   David Grinspoon and Alan Stern, The Washington Post. Excerpt: Three years ago, NASA’s New Horizons, the fastest spaceship ever launched, raced past Pluto, spectacularly revealing the wonders of that newly seen world. This coming New Year’s Eve — if all goes well on board this small robot operating extremely far from home — it will treat us to images of the most distant body ever explored, provisionally named Ultima Thule. We know very little about it, but we do know it’s not a planet. Pluto, by contrast — despite what you’ve heard — is. Why do we say this? ...We use “planet” to describe worlds with certain qualities. When we see one like Pluto, with its many familiar features — mountains of ice, glaciers of nitrogen, a blue sky with layers of smog — we and our colleagues quite naturally find ourselves using the word “planet” to describe it and compare it to other planets that ...

https://www.nytimes.com/2017/08/08/science/new-horizons-nasa-pluto-mu69-occultations.html Source:   By Kenneth Chang, The New York Times For Investigation:    6.1, 6.1 6.2, 8.2 Excerpt: This summer, scientists crisscrossed two oceans, braved wind and cold and deployed two dozen telescopes — all for five blinks of starlight that lasted a second or less. For the team working with NASA’s New Horizons spacecraft, which made a spectacular flyby of Pluto two years ago, those smidgens of data provide intriguing hints about the spacecraft’s next destination, a distant frozen world that is believed to be a pristine, undisturbed fragment from the earliest days of the solar system. New Horizons will fly past it on Jan. 1, 2019....

Source:   By JoAnna Wendel   Earth & Space News EoS (AGU) Excerpt: 1. Dwarf Planets Are as Complex as Regular Planets. ...2. Dwarf Planets Reveal Neptune’s Orbital Origins. ...3. Dwarf Planets Give Us a Peek into the Early Solar System. ...4. Dwarf Planet Candidates Helped Scientists “Find” Planet 9. ...5. Ceres (We Hope) Will Help Us Understand Icy Ocean Moons. ...6. Dwarf Planets Are Prolific.... https://eos.org/articles/six-things-dwarf-planets-have-taught-us-about-the-solar-system

Source:  The New York Times Excerpt:  Set foot on [Pluto] an alien world, three billion miles from the warmth of the sun. Download the NYT VR [virtual reality] app for Android or iPhone. [Different views are seen by moving the smart phone to different viewing angles. Or use cardboard viewer for effect]... http://www.nytimes.com/interactive/2016/05/19/science/space/seeking-plutos-frigid-heart-nytvr.html

Source:  NASA Feature Movie: https://www.youtube.com/watch?v=B0xkupKwjfM&feature=youtu.be Latest New Horizons Science Photos - http://pluto.jhuapl.edu/Multimedia/Science-Photos/index.php Images: http://pluto.jhuapl.edu/Multimedia/Science-Photos/pics/Very-Best-View-of-Pluto.png http://pluto.jhuapl.edu/Multimedia/Science-Photos/pics/Very-best-view-of-Pluto-%28mosaic%29.jpg nasa.gov page for New Horizons - https://www.nasa.gov/mission_pages/newhorizons/main/index.html https://www.nasa.gov/feature/new-horizons-returns-first-of-the-best-images-of-pluto

Source:   By S. A. Stern1, F. Bagenal, et al, Science. Abstract: The Pluto system was recently explored by NASA’s New Horizons spacecraft, making closest approach on 14 July 2015. Pluto’s surface displays diverse landforms, terrain ages, albedos, colors, and composition gradients. Evidence is found for a water-ice crust, geologically young surface units, surface ice convection, wind streaks, volatile transport, and glacial flow. Pluto’s atmosphere is highly extended, with trace hydrocarbons, a global haze layer, and a surface pressure near 10 microbars. Pluto’s diverse surface geology and long-term activity raise fundamental questions about how small planets remain active many billions of years after formation. Pluto’s large moon Charon displays tectonics and evidence for a heterogeneous crustal composition; its north pole displays puzzling dark terrain. Small satellites Hydra and Nix have higher albedos than expected....  For latest images from New Horizons Mission to Plu...

Source:   NASA Release 15-158 Excerpt: Flowing ice and a surprising extended haze are among the newest discoveries from NASA’s New Horizons mission, which reveal distant Pluto to be an icy world of wonders. “We knew that a mission to Pluto would bring some surprises, and now -- 10 days after closest approach -- we can say that our expectation has been more than surpassed,” said John Grunsfeld, NASA’s associate administrator for the Science Mission Directorate. “With flowing ices, exotic surface chemistry, mountain ranges, and vast haze, Pluto is showing a diversity of planetary geology that is truly thrilling." Just seven hours after closest approach, New Horizons aimed its Long Range Reconnaissance Imager (LORRI) back at Pluto, capturing sunlight streaming through the atmosphere and revealing hazes as high as 80 miles (130 kilometers) above Pluto’s surface. A preliminary analysis of the image shows two distinct layers of haze -- one about 50 miles (80 kilometers) ...

Source:   By  JoAnna Wendel ,  EoS Earth & Space Science News Excerpt:  Pluto’s moons Hydra and Nix appear in unprecedented sharpness in images released today from NASA’s New Horizons mission. For the first time, scientists are also able to estimate the sizes of these tiny natural satellites: Nix (left) at 26 miles (42 kilometers) by 22 miles (36 kilometers) and Hydra (right), 34 miles (55 kilometers) by 25 miles (40 kilometers). Nix’s new portrait, imaged in enhanced colors, shows a reddish patch reminiscent of a bull’s-eye. In a press release , scientists said that they suspect the region could be an impact crater on the jelly bean-shaped moon but are awaiting additional data from the spacecraft to better understand what they’ve observed. https://eos.org/articles/plutos-moons-nix-and-hydra-show-their-faces

Source:   Science online Excerpt: Today, NASA’s New Horizons team unveiled the latest trove of geological goodies in close-up pictures of the surface of Pluto: hummocky hills that rise up above smooth plains of ice, patches of ice pocked by eroded pits, and troughs that form the boundaries of mysterious polygonal structures. Most tantalizing of all, the team has spotted streaks of material that may have blown downwind from dark spots. Although the team is not yet ready to declare that these spots are geysers shooting plumes above Pluto, scientists say the spots and streaks resemble actively spewing geysers on Neptune’s moon Triton that were discovered in 1989. See also NASA Release 15-152, July 15, 2015: From Mountains to Moons: Multiple Discoveries from NASA’s New Horizons Pluto Mission - http://www.nasa.gov/press-release/from-mountains-to-moons-multiple-discoveries-from-nasa-s-new-horizons-pluto-mission 0 and  NASA Release 15-154, July 17, 2015: NASA’s New Hori...

Source:   NASA Release 15-149 NASA’s New Horizons spacecraft is at Pluto. After a decade-long journey through our solar system, New Horizons made its closest approach to Pluto Tuesday, about 7,750 miles above the surface -- roughly the same distance from New York to Mumbai, India – making it the first-ever space mission to explore a world so far from Earth. [photo taken on July 13, 2015 when the spacecraft was 476,000 miles (768,000 kilometers) from the surface. ...the last and most detailed image sent to Earth before the spacecraft’s closest approach to Pluto on July 14.] http://www.nasa.gov/press-release/nasas-three-billion-mile-journey-to-pluto-reaches-historic-encounter

Source:   NASA Release 15-111. Excerpt: If you lived on one of Pluto’s moons, you might have a hard time determining when, or from which direction, the sun will rise each day. Comprehensive analysis of data from NASA’s Hubble Space Telescope shows that two of Pluto’s moons, Nix and Hydra, wobble unpredictably. “Hubble has provided a new view of Pluto and its moons revealing a cosmic dance with a chaotic rhythm,” said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate in Washington. ...The moons wobble because they’re embedded in a gravitational field that shifts constantly. This shift is created by the double planet system of Pluto and Charon as they whirl about each other. Pluto and Charon are called a double planet because they share a common center of gravity located in the space between the bodies. Their variable gravitational field sends the smaller moons tumbling erratically. The effect is strengthened by the football-like, rather than spherical...

Source:  NASA,  Goddard Space Flight Center, ScienceDaily                Excerpt: … discovery of another moon orbiting the icy dwarf planet Pluto … estimated to be irregular in shape and 6 to 15 miles across … in a 58,000-mile-diameter circular orbit around Pluto…. The discovery increases the number of known moons orbiting Pluto to five. The Pluto team is intrigued that such a small planet can have such a complex collection of satellites. …"The discovery of so many small moons indirectly tells us that there must be lots of small particles lurking unseen in the Pluto system," said Harold Weaver of the Johns Hopkins University Applied Physics Laboratory…. www.sciencedaily.com/releases/2012/07/120711123038.htm

Source:    European Southern Observatory  Release eso1142 Excerpt: In November 2010, the distant dwarf planet Eris passed in front of a faint background star, an event called an occultation. …Occultations provide the most accurate, and often the only, way to measure the shape and size of a distant Solar System body. …The combined observations from the two Chilean sites indicate that Eris is close to spherical. …Eris… discovery was one of the factors that led to the creation of a new class of objects called dwarf planets and the reclassification of Pluto from planet to dwarf planet in 2006. Eris is currently three times further from the Sun than Pluto. …Eris’s newly determined diameter stands at 2326 kilometres, …This makes its size better known than that of its closer counterpart Pluto, which has a diameter estimated to be between 2300 and 2400 kilometres. …The motion of Eris’s satellite Dysnomia was used to estimate the mass of Eris …27% heavier than Pluto … Eris i...

Source:   Dauna Coulter, Science@NASA Excerpt: At this very moment one of the fastest spacecraft ever launched -- NASA's New Horizons -- is hurtling through the void at nearly one million miles per day. ... headed for the lonely world of Pluto on the outer edge of the solar system. Although astronomers now call Pluto a dwarf planet, "it's actually a large place, about 5,000 miles around at the equator," says Alan Stern, principal investigator for the mission. "And it's never been explored."  science.nasa.gov/science-news/science-at-nasa/2011/02sep_newhorizons/

Source:    NASA RELEASE: 11-234 Excerpt: Astronomers using the Hubble Space Telescope discovered a fourth moon orbiting the icy dwarf planet Pluto. The tiny, new satellite, temporarily designated P4, was uncovered in a Hubble survey searching for rings around the dwarf planet. The new moon is the smallest discovered around Pluto. It has an estimated diameter of 8 to 21 miles (13 to 34 km). By comparison, Charon, Pluto's largest moon, is 648 miles (1,043 km) across, and the other moons, Nix and Hydra, are in the range of 20 to 70 miles in diameter (32 to 113 km). ...The dwarf planet's entire moon system is believed to have formed by a collision between Pluto and another planet-sized body early in the history of the solar system.  …For images and more information about Hubble, visit: www.nasa.gov/hubble and http://hubblesite.org/news/2011/23    www.nasa.gov/home/hqnews/2011/jul/HQ_11-234_HST_Pluto_Moon.html

Source:   NASA RELEASE: 2011-234     Excerpt: Astronomers using the Hubble Space Telescope discovered a fourth moon orbiting the icy dwarf planet Pluto. The tiny, new satellite, temporarily designated P4, was uncovered in a Hubble survey searching for rings around the dwarf planet. The new moon is the smallest discovered around Pluto. It has an estimated diameter of 8 to 21 miles (13 to 34 km). By comparison, Charon, Pluto's largest moon, is 648 miles (1,043 km) across, and the other moons, Nix and Hydra, are in the range of 20 to 70 miles in diameter (32 to 113 km). ...The dwarf planet's entire moon system is believed to have formed by a collision between Pluto and another planet-sized body early in the history of the solar system.  …For images and more information about Hubble, visit: www.nasa.gov/hubble and http://hubblesite.org/news/2011/23    www.nasa.gov/home/hqnews/2011/jul/HQ_11-234_HST_Pluto_Moon.html

Source:   Nancy Atkinson, Universe Today Excerpt: … Eris — that pesky big dwarf planet that caused all the brouhaha about planets, dwarf planets, plutoids and the like — has gotten a closer look by a team of astronomers from several different universities, and guess what? Eris and Pluto have a lot in common. Eris appears to have a frozen surface, predominantly covered in nitrogen ice and methane, just like Pluto. …“By combining the astronomical data and laboratory data, we found about 90 percent of Eris’s icy surface is made up of nitrogen ice and about 10 percent is made up of methane ice, which is not all that different from Pluto,” said David Cornelison, coauthor and physicist at Missouri State University…. www.universetoday.com/75123/eris-and-pluto-two-peas-in-a-pod/