sábado, 17 de febrero de 2018

Five Years after the Chelyabinsk Meteor: NASA Leads Planetary Defense | NASA

Five Years after the Chelyabinsk Meteor: NASA Leads Planetary Defense | NASA



Five Years after the 

Chelyabinsk Meteor: NASA 

Leads Efforts in 

Planetary Defense

A blinding flash, a loud sonic boom, and shattered glass everywhere. This is what the people of Chelyabinsk, Russia, experienced five years ago when an asteroid exploded over their city the morning of Feb. 15, 2013.
Smoke trail in sky
This image of a vapor trail was captured about 125 miles (200 kilometers) from the Chelyabinsk meteor event, about one minute after the house-sized asteroid entered Earth’s atmosphere.
Credits: Alex Alishevskikh
The house-sized asteroid entered the atmosphere over Chelyabinsk at over eleven miles per second and blew apart 14 miles above the ground. The explosion released the energy equivalent of around 440,000 tons of TNT and generated a shock wave that blew out windows over 200 square miles and damaged some buildings. Over 1,600 people were injured in the blast, mostly due to broken glass.
“The Chelyabinsk event drew widespread attention to what more needs to be done to detect even larger asteroids before they strike our planet,” said NASA Planetary Defense Officer Lindley Johnson. “This was a cosmic wake-up call.”
Coincidentally, on the same day as the Chelyabinsk event, the United Nations Committee on Peaceful Uses of Outer Space Working Group on Near-Earth Objects was meeting in Vienna to finalize a recommendation to the U.N. on how to defend Earth from possible asteroid impacts. One result of this meeting was an endorsement by the U.N. General Assembly for the establishment of an International Asteroid Warning Network (IAWN) for worldwide collaboration on the detection and tracking of potential impact hazards and a Space Missions Planning Advisory Group (SMPAG) as a forum for the national space agencies to collaborate on plans for preventing any possible asteroid impact. In January 2014, the IAWN steering committee held its first meeting, and SMPAG met for the first time later that year.
“We must keep looking for what we know is still out there to be found.” - Lindley Johnson
At the same time, NASA’s Near Earth Object (NEO) Observations Program was growing in response to increased awareness of asteroid impact risks. The program focuses on finding asteroids 460 feet (140 meters) and larger that represent the most severe impact risks to Earth. The goal of the program is to find at least 90 percent of these asteroids early enough to allow deflection or other preparations for impact mitigation. By January 2018, discovery of near-Earth objects of all sizes had surpassed the 17,500 mark – an 84 percent increase since January 2013.
“Thanks to upgraded telescopes coming online in recent years, the rate of asteroid discovery has increased considerably,” said Kelly Fast, manager of NASA’s NEO Observations Program. “Over 8,000 of these larger asteroids are now being tracked. However, there are over twice that number still out there to be found.”
In January 2016, NASA established a Planetary Defense Coordination Office (PDCO), tasked with ensuring the early detection of potentially hazardous objects – asteroids and comets whose orbits can bring them within about 5 million miles (8 million kilometers) of Earth, and of a size large enough to reach Earth’s surface.  PDCO is responsible for tracking and characterizing any potentially hazardous objects, issuing warnings about potential impacts, and providing timely and accurate communications about any actual impact threat while leading the coordination of U.S. Government planning for a response. The NEO Observations Program, a primary element of the PDCO, provides data from projects supported by the program to fulfill these responsibilities.
NASA works with the Federal Emergency Management Agency (FEMA) to lead U.S. Government planning for response to an actual impact threat. “We’ve conducted a series of ‘tabletop exercises’ with FEMA and other U.S. government agencies to simulate the events of an impending catastrophic asteroid impact with Earth to increase our emergency preparedness for it, and we’re planning more,” said Johnson. “We also work closely with our international colleagues in the International Asteroid Warning Network and the Space Missions Planning Advisory Group.”
Going beyond simulations, NASA also is undertaking the Double Asteroid Redirection Test (DART), a space-flight mission designed to demonstrate the kinetic-impact technique for nudging an asteroid off a predicted impact course with Earth. Launch is tentatively set for early to mid-2021. The Planetary Defense Coordination Office also is supporting development of concepts for a space-based asteroid search, detection and tracking mission.
In 2017, the first “test” of a global asteroid-impact early-warning system took place. The observation campaign was conceived and organized by NASA-funded asteroid observers, overseen by NASA, and included participants from the International Asteroid Warning Network and other international partners. The target of this observing campaign was an asteroid known as 2012 TC4. While scientists knew enough from the short period of discovery observations back in 2012 that it would safely pass Earth this last October, its precise path was uncertain, so it was an ideal target for a planetary defense exercise.
This early-warning-system test went well. Fast noted, “This was a successful real-life exercise for NASA and for the International Asteroid Warning Network, with smooth recovery of the object, precise prediction of the orbit and tracking of the asteroid as it passed about 27,000 miles from Earth’s surface on October 12th.”
While no known asteroid is predicted to be on an impact course with Earth for the next 100 years, the search goes on, and preparations for planetary defense continue. Said Johnson, “We must keep looking for what we know is still out there to be found.”
Keep up to date on upcoming close approaches of near-Earth objects
Last Updated: Feb. 15, 2018
Editor: Tricia Talbert

Hubble's Window into the Cosmic Past | NASA

Hubble's Window into the Cosmic Past | NASA



Hubble's Window into 

the Cosmic Past

stars, galaxies and lensed galaxies
This image from the NASA/ESA Hubble Space Telescope shows the galaxy cluster PLCK G004.5-19.5. It was discovered by the ESA Planck satellite through the Sunyaev-Zel’dovich effect — the distortion of the cosmic microwave background radiation in the direction of the galaxy cluster by high-energy electrons in the intracluster gas. The large galaxy at the center is the brightest galaxy in the cluster, and above it a thin, curved gravitational lens arc is visible. This arc is caused by the gravitational forces of the cluster bending the path of light from stars and galaxies behind it, in a similar way to how a glass lens bends light.
Several stars are visible in front of the cluster — recognizable by their diffraction spikes — but aside from these, all other visible objects are distant galaxies. Their light has become redshifted by the expansion of space, making them appear redder than they actually are. By measuring the amount of redshift, we know that it took more than 5 billion years for the light from this galaxy cluster to reach us. The light of the galaxies in the background had to travel even longer than that, making this image an extremely old window into the far reaches of the universe.
This image was taken by Hubble’s Advanced Camera for Surveys (ACS) and Wide Field Camera 3 (WFC3) as part of an observing program called RELICS (Reionization Lensing Cluster Survey). RELICS imaged 41 massive galaxy clusters with the aim of finding the brightest distant galaxies for the forthcoming NASA James Webb Space Telescope to study.

Credit: ESA/Hubble & NASA, RELICS; Acknowledgement: D. Coe et al.
Text: European Space Agency
Last Updated: Feb. 16, 2018
Editor: Karl Hille

Imagining the Planets of TRAPPIST-1



Imagining the Planets of TRAPPIST-1


This video shows artist's concepts of the seven Earth-sized planets of TRAPPIST-1, an exoplanet system about 40 light-years away, based on data current as of February 2018. Each planet is shown in sequence, starting with the innermost TRAPPIST-1 b and ending with the outermost TRAPPIST-1 h. The video presents the planets’ relative sizes as well as the relative scale of the central star as seen from each planet. The art highlights possibilities for how the surfaces of these intriguing worlds might look based on their newly-calculated properties. The seven planets of TRAPPIST-1 are all Earth-sized and terrestrial. TRAPPIST-1 is an ultra-cool dwarf star in the constellation Aquarius, and its planets orbit very close to it. In the background, slightly distorted versions our familiar constellations, including Orion and Taurus, are shown as they would appear from the location of TRAPPIST-1 (backdrop image courtesy California Academy of Sciences/Dan Tell).

Hubble Observes Atmospheres of TRAPPIST-1 Exoplanets in the Habitable Zone



Hubble Observes Atmospheres of TRAPPIST-1 Exoplanets in the Habitable Zone



Astronomers using the Hubble Space Telescope have conducted the first spectroscopic survey of Earth-sized planets in the TRAPPIST-1 system's habitable zone. Hubble reveals that at least the inner five planets do not seem to contain puffy, hydrogen-rich atmospheres similar to gaseous planets such as Neptune. This means the atmospheres may be more shallow and rich in heavier gases like carbon dioxide, methane, and oxygen. Find the full story and press release at http://hubblesite.org/news_release/news/2018-07 The Nature Astronomy science paper is available at https://doi.org/10.1038/s41550-017-0374-z Credit: NASA’s Goddard Space Flight Center/Katrina Jackson Music credit: "Deep Groove" by Danny McCarthy [ASCAP] and Thomas Dill [ASCAP]; Soundcast Music SESAC; Chronic Trax; Killer Tracks Production Music This video is public domain and along with other supporting visualizations can be downloaded from the Scientific Visualization Studio at: https://svs.gsfc.nasa.gov/12844 If you liked this video, subscribe to the NASA Goddard YouTube channel: https://www.youtube.com/NASAExplorer Or subscribe to NASA’s Goddard Shorts HD Podcast: https://svs.gsfc.nasa.gov/vis/iTunes/f0004_index.htmlFollow NASA’s Goddard Space Flight Center · Facebook: https://www.facebook.com/NASA.GSFC · Twitter https://twitter.com/NASAGoddard · Flickr https://www.flickr.com/photos/gsfc/ · Instagram https://www.instagram.com/nasagoddard/ · Google+ https://plus.google.com/+NASAGoddard/posts

Hubble Watches Neptune’s Dark Storm Die


Hubble Watches Neptune’s Dark Storm Die



For the first time, NASA's Hubble Space Telescope has captured time-lapse images of a large, dark storm on Neptune shrinking out of existence. A recent Hubble program called Outer Planets Atmosphere Legacy, or OPAL, provides yearly global maps of our gas giant planets, allowing planetary scientists to view changes in formations such as Neptune's dark storms. Read the full story on https://www.nasa.gov/feature/goddard/2018/hubble-sees-neptunes-mysterious-shrinking-storm View the full image release - http://hubblesite.org/news_release/news/2018-08 Find the science paper - https://media.stsci.edu/preview/file/science_paper/file_attachment/306/wong_accepted_AJ_paper.pdfCredit: NASA’s Goddard Space Flight Center/Katrina Jackson Music credit: "Struggling in the City" by Emre Ramazanoglu [PRS], Jamie Michael Bradley Reddington [PRS], and Patrick Green [PRS]; Atmosphere Music Ltd [PRS]; BLOCK; Killer Tracks Production Music This video is public domain and along with other supporting visualizations can be downloaded from the Scientific Visualization Studio at: https://svs.gsfc.nasa.gov/12862 If you liked this video, subscribe to the NASA Goddard YouTube channel: https://www.youtube.com/NASAExplorerOr subscribe to NASA’s Goddard Shorts HD Podcast: https://svs.gsfc.nasa.gov/vis/iTunes/f0004_index.htmlFollow NASA’s Goddard Space Flight Center · Facebook: https://www.facebook.com/NASA.GSFC · Twitter https://twitter.com/NASAGoddard · Flickr https://www.flickr.com/photos/gsfc/ · Instagram https://www.instagram.com/nasagoddard/ · Google+ https://plus.google.com/+NASAGoddard/posts

Hubble Sees Neptune's Mysterious Shrinking Storm | NASA

Hubble Sees Neptune's Mysterious Shrinking Storm | NASA



Hubble Sees Neptune's 

Mysterious Shrinking Storm

Three billion miles away on the farthest known major planet in our solar system, an ominous, dark storm – once big enough to stretch across the Atlantic Ocean from Boston to Portugal – is shrinking out of existence as seen in pictures of Neptune taken by NASA’s Hubble Space Telescope.
Immense dark storms on Neptune were first discovered in the late 1980s by NASA’s Voyager 2 spacecraft. Since then, only Hubble has had the sharpness in blue light to track these elusive features that have played a game of peek-a-boo over the years. Hubble found two dark storms that appeared in the mid-1990s and then vanished. This latest storm was first seen in 2015, but is now shrinking.
For the first time, NASA's Hubble Space Telescope has captured time-lapse images of a large, dark storm on Neptune shrinking out of existence.
Credits: NASA Goddard's Scientific Visualization Studio
Like Jupiter’s Great Red Spot (GRS), the storm swirls in an anti-cyclonic direction and is dredging up material from deep inside the ice giant planet’s atmosphere. The elusive feature gives astronomers a unique opportunity to study Neptune’s deep winds, which can’t be directly measured.
The dark spot material may be hydrogen sulfide, with the pungent smell of rotten eggs. Joshua Tollefson from the University of California at Berkeley explained, “The particles themselves are still highly reflective; they are just slightly darker than the particles in the surrounding atmosphere.”
Unlike Jupiter’s GRS, which has been visible for at least 200 years, Neptune’s dark vortices only last a few years. This is the first one that actually has been photographed as it is dying.
“We have no evidence of how these vortices are formed or how fast they rotate,” said Agustín Sánchez-Lavega from the University of the Basque Country in Spain. “It is most likely that they arise from an instability in the sheared eastward and westward winds.”
four part image with globes of neptune over BW closeups
This series of Hubble Space Telescope images taken over 2 years tracks the demise of a giant dark vortex on the planet Neptune. The oval-shaped spot has shrunk from 3,100 miles across its long axis to 2,300 miles across, over the Hubble observation period.
Credits: NASA, ESA, and M.H. Wong and A.I. Hsu (UC Berkeley)
The dark vortex is behaving differently from what planet-watchers predicted. “It looks like we’re capturing the demise of this dark vortex, and it’s different from what well-known studies led us to expect,” said Michael H. Wong of the University of California at Berkeley, referring to work by Ray LeBeau (now at St. Louis University) and Tim Dowling’s team at the University of Louisville. “Their dynamical simulations said that anticyclones under Neptune’s wind shear would probably drift toward the equator. We thought that once the vortex got too close to the equator, it would break up and perhaps create a spectacular outburst of cloud activity.”
But the dark spot, which was first seen at mid-southern latitudes, has apparently faded away rather than going out with a bang. That may be related to the surprising direction of its measured drift: toward the south pole, instead of northward toward the equator. Unlike Jupiter’s GRS, the Neptune spot is not as tightly constrained by numerous alternating wind jets (seen as bands in Jupiter’s atmosphere). Neptune seems to only have three broad jets: a westward one at the equator, and eastward ones around the north and south poles. The vortex should be free to change traffic lanes and cruise anywhere in between the jets.
“No facilities other than Hubble and Voyager have observed these vortices. For now, only Hubble can provide the data we need to understand how common or rare these fascinating neptunian weather systems may be,” said Wong.
The first images of the dark vortex are from the Outer Planet Atmospheres Legacy (OPAL) program, a long-term Hubble project that annually captures global maps of our solar system’s four outer planets. Only Hubble has the unique capability to probe these worlds in ultraviolet light, which yields important information not available to other present-day telescopes. Additional data, from a Hubble program targeting the dark vortex, are from an international team including Wong, Tollefson, Sánchez-Lavega, Andrew Hsu, Imke de Pater, Amy Simon, Ricardo Hueso, Lawrence Sromovsky, Patrick Fry, Statia Luszcz-Cook, Heidi Hammel, Marc Delcroix, Katherine de Kleer, Glenn Orton, and Christoph Baranec.
Wong’s paper appears online in the Astronomical Journal on Feb. 15, 2018.
The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.
For additional imagery, visit: http://hubblesite.org/news_release/news/2018-08
For NASA’s Hubble web page, visit: www.nasa.gov/hubble

Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4514
villard@stsci.edu
Last Updated: Feb. 15, 2018
Editor: Karl Hille

Jupiter’s Swirling Cloud Formations | NASA

Jupiter’s Swirling Cloud Formations | NASA



Jupiter’s Swirling 

Cloud Formations

Jupiter
See swirling cloud formations in the northern area of Jupiter's north temperate belt in this new view taken by NASA’s Juno spacecraft.
The color-enhanced image was taken on Feb. 7 at 5:42 a.m. PST (8:42 a.m. EST), as Juno performed its eleventh close flyby of Jupiter. At the time the image was taken, the spacecraft was about 5,086 miles (8,186 kilometers) from the tops of the clouds of the planet at a latitude of 39.9 degrees.
Citizen scientist Kevin M. Gill processed this image using data from the JunoCam imager.
JunoCam's raw images are available for the public to peruse and process into image products at:
More information about Juno is at:
Image credits: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill
Last Updated: Feb. 16, 2018
Editor: Tony Greicius