Viewing the South Pole of Vesta and Rhea Silvia Impact Basin. This image obtained by Dawn’s framing camera shows the south pole of the giant asteroid Vesta and the circular Rheasilvia impact basin which scientists believe originated by a collision with another asteroid early in the asteroid's history. The image was recorded from a distance of about 1,700 miles (2,700 kilometers). The image resolution is about 260 meters per pixel. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
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The mysterious asteroid Vesta may well have more surprises in store. Despite past observations that Vesta would be nearly bone dry, newly published research indicates that about half of the giant asteroid is sufficiently cold and dark enough that water ice could theoretically exist below the battered surface.
Scientists working at NASA’s Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland have derived the first models of Vesta’s average global temperatures and illumination by the Sun based on data obtained from the Hubble Space Telescope.
“Near the north and south poles, the conditions appear to be favorable for water ice to exist beneath the surface,” says Timothy Stubbs of NASA’s Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland, Baltimore County. The research by Timothy Stubbs and Yongli Wang, of the Goddard Planetary Heliophysics Institute at the University of Maryland, was published in the January 2012 issue of the journal Icarus.
If any water lurks beneath Vesta, it would most likely exist at least 10 feet (3 meters) below the North and South poles because the models predict that the poles are the coldest regions on the giant asteroid and the equatorial regions are too warm. Global Map of Average Surface Temperature of Vesta
This global map of average surface temperature shows the warmer equatorial zone of the giant asteroid Vesta is likely too warm to sustain water ice below the surface. But roughly half of Vesta is so cold and receives so little sunlight on average that water ice could have survived there for billions of years. The dividing lines (solid gray) are found at about 27 degrees north latitude and 27 degrees south latitude. This map, with temperatures given in kelvins, comes from the first published models of the average global temperature and illumination conditions on Vesta. Credit: NASA/GSFC/UMBC
If proven, the existence of water ice at Vesta would have vast implications for the formation and evolution of the tiny body and upend current theories.
The surface of Vesta is not cold enough for ice to survive all the time because unlike the Moon, it probably does not have any significant permanently shadowed craters where water ice could stay frozen on the surface indefinitely.
Even the huge 300 mile diameter (480-kilometer) crater at the South Pole is not a good candidate for water ice because Vesta is tilted 27 degrees on its axis, a bit more than Earth’s tilt of 23 degrees.
By contrast, the Moon is only tilted 1.5 degrees and possesses many permanently shadowed craters. NASA’s LCROSS impact mission proved that water ice exists inside permanently shadowed lunar craters.
New modeling shows that, under present conditions, Vesta's polar regions are cold enough (less than about 145 kelvins) to sustain water ice for billions of years, as this map of average surface temperature around the asteroid's south pole indicates.
The models predict that the average annual temperature around Vesta’s poles is below minus 200 degrees Fahrenheit (145 kelvins). Water ice is not stable above that temperature in the top 10 feet of Vestan soil, or regolith.
At the equator and in a band stretching to about 27 degrees north and south in latitude, the average annual temperature is about minus 190 degrees Fahrenheit (145 kelvins), which is too high for the ice to survive.
“On average, it’s colder at Vesta’s poles than near its equator, so in that sense, they are good places to sustain water ice,” says Stubbs in a NASA statement. “But they also see sunlight for long periods of time during the summer seasons, which isn’t so good for sustaining ice. So if water ice exists in those regions, it may be buried beneath a relatively deep layer of dry regolith.”
Vesta is the second most massive asteroid in the main Asteroid belt between Mars and Jupiter.
NASA’s Dawn Asteroid Orbiter is the very first mission to Vesta and achieved orbit in July 2011 for a 1 year long mission.
Dawn is currently circling Vesta at its lowest planned orbit. The three science instruments are snapping pictures and the spectrometers are collecting data on the elemental and mineralogical composition of Vesta.
The onboard GRaND spectrometer in particular could shed light on the question of whether water ice exists at Vesta.
So far no water has been detected, but the best data is yet to come.
In July 2012, Dawn fires up its ion thrusters and spirals out of orbit to begin the journey to Ceres, the largest asteroid of them all.
Ceres is believed to harbor huge caches of water, either as ice or in the form of oceans and is a potential habitat for life.
A 5-km-wide crater on Vesta displays light and dark material.
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Light and dark material spreads outward from a 5-km-wide crater on Vesta in this image from NASA’s Dawn spacecraft, acquired on October 22, 2011. While craters with differently-toned materials have been previously seen on the asteroid, it is unusual to find one with such a large amount of ejecta of different albedos.
This is a crop of a larger version which was released today on the Dawn website.
This brightness image was taken through the clear filter of Dawn’s framing camera. The distance to the surface of Vesta is 700 kilometers (435 miles) and the image has a resolution of about 70 meters (230 feet) per pixel.
Vesta resides in the main asteroid belt between the orbits of Mars and Jupiter and is thought to be the source of many of the meteorites that fall to Earth. The Dawn spacecraft successfully entered orbit around Vesta on July 16, 2011.
After its investigation of Vesta, Dawn will leave orbit and move on to Ceres. It will become the first spacecraft to orbit two different worlds.
Image Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
Orbital parameters of Asteroid 2012 BX34 from JPL's Small Body Database.
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A small asteroid will pass extremely close to Earth tomorrow (January 27, 2012). Named 2012 BX34, this 11 meter- (36 feet-) wide 8 meter- (26-foot-) space rock (astronomers have updated their estimates of the size) will skim Earth less than 60,000 km (37,000 miles, .0004 AU)>, at around 15:30 UTC, (10:30 am EST) according to the Minor Planet Center. The latest estimates have this small bus-sized asteroid it traveling at about about 8,900 meters/second (about 20,000 miles per hour). 2012 BX34 has been observed by the Catalina Sky Survey and the Mt. Lemmon Survey in Arizona, and the Magdalena Ridge Observatory in New Mexico, so its orbit is well defined and there is no risk of impact to Earth.
Via the @AsteroidWatch Twitter feed, scientists from JPL said “It wouldn’t get through our atmosphere intact even if it dared to try.”
Amateur astronomers in the right place and time could view this object, as it should be about magnitude 14 at the time of closest approach. Click here to see a current orbit diagram, and here to view the ephemeris data. Nick Howes, with the Faulkes Telescope Project said his team is hoping to observe and image the asteroid, — although they aren’t sure if they will be able — but we hope to share their images later.
This radar image of asteroid 2005 YU55 was obtained on Nov. 7, 2011. Credit: NASA/JPL/Caltech.
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Look up in a clear night sky. How many moons do you see? Chances are, you’re only going to count to one. Admittedly, if you count any higher and you’re not alone, you may get some funny looks cast in your direction. But even though you may not be able to actually see them, there may very well be more moons out there orbiting our planet.
For the time being, anyway.
Today, Earth has one major moon in orbit around it. (Technically the Earth-Moon system orbits around a common center of gravity, called the barycenter, but that’s splitting hairs for the purpose of this story.) At one time Earth may have had two large moons until the smaller eventually collided into the larger, creating the rugged lump we now call the farside highlands. But, that was 4 billion years ago and again not what’s being referred to here.
Right now, at his moment, Earth may very well have more than the one moon we see in the night sky. Surprise.
Of course, it would be a very small moon. Perhaps no more than a meter across. But a moon nonetheless. And there could even be others – many others – much smaller than that. Little bits of solar system leftovers, orbiting our planet even farther out than the Moon we all know and love, coming and going in short-lived flings with Earth without anyone even knowing.
This is what has been suggested by researcher Mikael Granvik of the University of Helsinki in Finland. He and his colleagues have created computer simulations of asteroids believed to be occupying the inner solar system, and what the chances are that any number of them could be captured into Earth orbit at any given time.
Orbit of 2006 RH120, a confirmed TCO identified in 2006.
The team’s results, posted Dec. 20 in the science journal Icarus, claim it’s very likely that small asteroids would be temporarily captured into orbit (becoming TCOs, or temporarily captured objects) on a regular basis, each spending about nine months in up to three revolutions around Earth before heading off again.
Some objects, though, might hang around even longer… in the team’s simulations one TCO remained in orbit for 900 years.
“There are lots of asteroids in the solar system, so chances for the Earth to capture one at any time is, in a sense, not surprising,” said co-author Jeremie Vauballion, an astronomer at the Paris Observatory.
In fact, the team suspects that there’s most likely a TCO out there right now, perhaps a meter or so wide, orbiting between 5 and 10 times the distance between Earth and the Moon. And there could be a thousand smaller ones as well, up to 10 centimeters wide.
So if these moons are indeed out there, why don’t we know about them?
Put simply, they are too small, too far, and too dark.
At that distance an object the size of a writing desk is virtually undetectable with the instruments we have now.. especially if we don’t even know exactly where to look. But in the future the Large Synoptic Survey Telescope (LSST) may, once completed, be able to spot these tiny satellites with its 3200-megapixel camera.
Once spotted, TCOs could become targets of exploration. After all, they are asteroids that have come to us, which would make investigation all the easier – not to mention cheaper – much more so than traveling to and back from the main asteroid belt.
“The price of the mission would actually be pretty small,” Granvik said. And that, of course, makes the chances of such a mission getting approved all the better.
Read more on David Shiga’s article on New Scientist here.
Dawn Orbiting Vesta. NASA's Dawn spacecraft achieved orbit at the giant asteroid Vesta in July 2011. The depiction of Vesta is based on images obtained by Dawn's framing cameras. Dawn is an international collaboration of the US, Germany and Italy. Credit: NASA/JPL-Caltech
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A year ago, 2011 was proclaimed as the “Year of the Solar System” by NASA’s Planetary Science division. And what a year of excitement it was indeed for the planetary science community, amateur astronomers and the general public alike !
NASA successfully delivered astounding results on all fronts – On the Story of How We Came to Be.
“2011 was definitely the best year ever for NASA Planetary Science!” said Jim Green in an exclusive interview with Universe Today. Green is the Director of Planetary Science for the Science Mission Directorate at NASA HQ. “The Search for Life is a significant priority for NASA.”
This past year was without doubt simply breathtaking in scope in terms of new missions, new discoveries and extraordinary technical achievements. The comprehensive list of celestial targets investigated in 2011 spanned virtually every type of object in our solar system – from the innermost planet to the outermost reaches nearly touching interplanetary space.
There was even a stunningly evocative picture showing “All of Humanity” – especially appropriate now in this Holiday season ! You and all of Humanity are here !
-- Earth & Moon Portrait by Juno from 6 Million miles away --
First Photo transmitted from Jupiter Bound Juno shows Earth (on the left) and the Moon (on the right). Taken on Aug. 26, 2011 when spacecraft was about 6 million miles (9.66 million kilometers) away from Earth. Credit: NASA/JPL-Caltech
Three brand new missions were launched and ongoing missions orbited a planet and an asteroid and flew past a comet.
“NASA has never had the pace of so many planetary launches in such a short time,” said Green.
And three missions here were awarded ‘Best of 2011’ for innovation !
Mars Science Laboratory (MSL), Dawn and MESSENGER named “Best of What’s New” in 2011 by Popular Science magazine. 3 NASA Planetary Science missions received the innovation award for 2011 from Popular Science magazine. Artist concept shows mosaic of MESSENGER, Mars Science Laboratory and Dawn missions. Credit: NASA/JPL-Caltech
Here’s the Top NASA Planetary Science Stories of 2011 – ‘The Year of the Solar System’ – in chronological order
1. Stardust-NExT Fly By of Comet Tempel 1
Starting from the first moments of 2011 at the dawn of Jan. 1, hopes were already running high for planetary scientists and engineers busily engaged in setting up a romantic celestial date in space between a volatile icy comet and an aging, thrusting probe on Valentine’s Day.
The comet chasing Stardust-Next spacecraft successfully zoomed past Comet Tempel 1 on Feb. 14 at 10.9 km/sec (24,000 MPH) after flying over 6 Billion kilometers (3.5 Billion mi).
6 Views of Comet Tempel 1 and Deep Impact crater during Stardust-NExT flyby on Feb. 14, 2011
Arrows show location of man-made crater created in 2005 by NASA’s prior Deep Impact comet mission and newly imaged as Stardust-NExT zoomed past comet in 2011. The images progress in time during closest approach to comet beginning at upper left and moving clockwise to lower left. Credit: NASA/JPL-Caltech/University of Maryland. Post process and annotations by Marco Di Lorenzo & Kenneth Kremer
The craft approached within 178 km (111mi) and snapped 72 astonishingly detailed high resolution science images over barely 8 minutes. It also fulfilled the teams highest hopes by photographing the human-made crater created on Tempel 1 in 2005 by a cosmic collision with a penetrator hurled by NASA’s Deep Impact spacecraft. The probe previously flew by Comet Wild 2 in 2004 and returned cometary coma particles to Earth in 2006
Tempel 1 is the first comet to be visited by two spaceships from Earth and provided the first-ever opportunity to compare observations on two successive passages around the Sun.
Don Brownlee, the original Principal Investigator, summarized the results for Universe Today; “A great bonus of the mission was the ability to flyby two comets and take images and measurements. The wonderfully successful flyby of Comet Tempel 1 was a great cap to the 12 year mission and provided a great deal of new information to study the diversity among comets.”
“The new images of Tempel showed features that form a link between seemingly disparate surface features of the 4 comets imaged by spacecraft. Combining data on the same comet from the Deep Impact and Stardust missions has provided important new insights in to how comet surfaces evolve over time and how they release gas and dust into space”.
2. MESSENGER at Mercury
On March 18, the Mercury Surface, Space Environment, Geochemistry, and Ranging, or MESSENGER, spacecraft became the first spacecraft inserted into orbit around Mercury, the innermost planet.
So far MESSENGER has completed 1 solar day – 176 Earth days- circling above Mercury. The probe has collected a treasure trove of new data from the seven instruments onboard yielding a scientific bonanza; these include global imagery of most of the surface, measurements of the planet’s surface chemical composition, topographic evidence for significant amounts of water ice, magnetic field and interactions with the solar wind.
“MESSENGER discovered that Mercury has an enormous core, larger than Earth’s. We are trying to understand why that is and why Mercury’s density is similar to Earth’s,” Jim Green explained to Universe Today.
The First Solar Day
After its first Mercury solar day (176 Earth days) in orbit, MESSENGER has nearly completed two of its main global imaging campaigns: a monochrome map at 250 m/pixel and an eight-color, 1-km/pixel color map. Small gaps will be filled in during the next solar day. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington
“The primary mission lasts 2 solar days, equivalent to 4 Mercury years.”
“NASA has granted a 1 year mission extension, for a total of 8 Mercury years. This will allow the team to understand the environment at Mercury during Solar Maximum for the first time. All prior spacecraft observations were closer to solar minimum,” said Green.
MESSENGER was launched in 2004 and the goal is to produce the first global scientific observations of Mercury and piece together the puzzle of how Mercury fits in with the origin and evolution of our solar system.
NASA’s Mariner 10 was the only previous robotic probe to explore Mercury, during three flyby’s back in the mid-1970’s early in the space age.
3. Dawn Asteroid Orbiter
The Dawn spacecraft achieved orbit around the giant asteroid Vesta in July 2011 after a four year interplanetary cruise and began transmitting the history making first ever close-up observations of the mysteriously diverse and alien world that is nothing short of a ‘Space Spectacular’.
“We do not have a good analog to Vesta anywhere else in the Solar System,” Chris Russell said to Universe Today. Russell, from UCLA, is the scientific Principal Investigator for Dawn.
Before Dawn, Vesta was just another fuzzy blob in the most powerful telescopes. Dawn has completely unveiled Vesta as a remarkably dichotomous, heavily battered and pockmarked world that’s littered with thousands of craters, mountains and landslides and ringed by mystifying grooves and troughs. It will unlock details about the elemental abundances, chemical composition and interior structure of this marvelously intriguing body.
Cataclysmic collisions eons ago excavated Vesta so it lacks a south pole. Dawn discovered that what unexpectedly remains is an enormous mountain some 16 miles (25 kilometers) high, twice the height of Mt. Everest.
Dawn is now about midway through its 1 year mission at Vesta which ends in July 2012 with a departure for Ceres, the largest asteroid. So far the framing cameras have snapped more than 10,000 never-before-seen images.
“What can be more exciting than to explore an alien world that until recently was virtually unknown!. ” Dr. Marc Rayman said to Universe Today. Rayman is Dawn’s Chief Engineer from NASA’s Jet Propulsion Lab (JPL) in Pasadena, Calif.
“Dawn is NASA at its best: ambitious, exciting, innovative, and productive.”
4. Juno Jupiter Orbiter
The solar powered Juno spacecraft was launched on Aug. 5 at Cape Canaveral Air Force Station in Florida, to embark on a five year, 2.8 billion kilometer (1.7 Billion mi) trek to Jupiter, our solar system’s largest planet. It was the first of three NASA planetary science liftoffs scheduled in 2011.
Juno Jupiter Orbiter soars skyward to Jupiter on Aug. 5, 2011 from Cape Canaveral Air Force Station, Florida. Credit: Ken Kremer
Juno’s goal is to map to the depths of the planets interior and elucidate the ingredients of Jupiter’s genesis hidden deep inside. These measurements will help answer how Jupiter’s birth and evolution applies to the formation of the other eight planets.
The 4 ton spacecraft will arrive at the gas giant in July 2016 and fire its braking rockets to go into a polar orbit and circle the planet 33 times over about one year.
The suite of nine instruments will scan the gas giant to find out more about the planets origins, interior structure and atmosphere, measure the amount of water and ammonia, observe the aurora, map the intense magnetic field and search for the existence of a solid planetary core.
“Jupiter is the Rosetta Stone of our solar system,” said Scott Bolton, Juno’s principal investigator from the Southwest Research Institute in San Antonio. “It is by far the oldest planet, contains more material than all the other planets, asteroids and comets combined and carries deep inside it the story of not only the solar system but of us. Juno is going there as our emissary — to interpret what Jupiter has to say.”
5. Opportunity reaches Endeavour Crater on Mars
The long lived Opportunity rover finally arrived at the rim of the vast 14 mile (22 kilometer) wide Endeavour Crater in mid-August 2011 following an epic three year trek across treacherous dune fields – a feat once thought unimaginable. All told, Opportunity has driven more than 34 km ( 21 mi) since landing on the Red Planet way back in 2004 for a mere 90 sol mission.
Endeavour Crater Panorama from Opportunity Mars Rover in August 2011
Opportunity arrived at the rim of Endeavour on Sol 2681, August 9, 2011 after a three year trek. The robot photographed segments of the huge craters eroded rim in this panoramic vista. Endeavour Crater is 14 miles (22 kilometers) in diameter. Mosaic Credit: NASA/JPL/Cornell/Marco Di Lorenzo/Kenneth Kremer
In November, the rover discovered the most scientifically compelling evidence yet for the flow of liquid water on ancient Mars in the form of a water related mineral vein at a spot dubbed “Homestake” along an eroded ridge of Endeavour’s rim.
Read my story about the Homestake discovery here, along with our panoramic mosaic showing the location – created by Ken Kremer and Marco Di Lorenzo and published by Astronomy Picture of the Day (APOD) on 12 Dec. 2011.
Watch for my upcoming story detailing Opportunity’s accomplishments in 2011.
6. GRAIL Moon Mappers
The Gravity Recovery and Interior Laboratory, or GRAIL mission is comprised of twin spacecraft tasked to map the moon’s gravity and study the structure of the lunar interior from crust to core.
Twin GRAIL Probes GO for Lunar Orbit Insertion on New Year’s Eve and New Year’s Day
GRAIL spacecraft will map the moon's gravity field and interior composition. Credit: NASA/JPL-Caltech
The dynamic duo lifted off from Cape Canaveral on September 10, 2011 atop the last Delta II rocket that will likely soar to space from Florida. After a three month voyage of more than 2.5 million miles (4 million kilometers) since blastoff, the two mirror image GRAIL spacecraft dubbed Grail-A and GRAIL-B are sailing on a trajectory placing them on a course over the Moon’s south pole on New Year’s weekend.
Each spacecraft will fire the braking rockets for about 40 minutes for insertion into Lunar Orbit about 25 hours apart on New Year’s Eve and New Year’s Day.
Engineers will then gradually lower the satellites to a near-polar near-circular orbital altitude of about 34 miles (55 kilometers).
The spacecraft will fly in tandem and the 82 day science phase will begin in March 2012.
“GRAIL is a Journey to the Center of the Moon”, says Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology (MIT). “GRAIL will rewrite the book on the formation of the moon and the beginning of us.”
“By globally mapping the moon’s gravity field to high precision scientists can deduce information about the interior structure, density and composition of the lunar interior. We’ll evaluate whether there even is a solid or liquid core or a mixture and advance the understanding of the thermal evolution of the moon and the solar system,” explained co-investigator Sami Asmar to Universe Today. Asmar is from NASA’s Jet Propulsion Laboratory (JPL)
7. Curiosity Mars Rover
The Curiosity Mars Science Lab (MSL) rover soared skywards on Nov. 26, the last of 2011’s three planetary science missions. Curiosity is the newest, largest and most technologically sophisticated robotic surveyor that NASA has ever assembled.
“MSL packs the most bang for the buck yet sent to Mars.” John Grotzinger, the Mars Science Laboratory Project Scientist of the California Institute of Technology, told Universe Today.
The three meter long robot is the first astrobiology mission since the Viking landers in the 1970’s and specifically tasked to hunt for the ‘Ingredients of Life’ on Mars – the most Earth-like planet in our Solar System.
Video caption: Action packed animation depicts sequences of Curiosity departing Earth, the nail biting terror of the never before used entry, descent and landing on the Martian surface and then looking for signs of life at Gale Crater during her minimum two year expedition across hitherto unseen and unexplored Martian landscapes, mountains and craters. Credit: NASA
Curiosity will gather and analyze samples of Martian dirt in pursuit of the tell-tale signatures of life in the form of organic molecules – the carbon based building blocks of life as we know it.
NASA is targeting Curiosity to a pinpoint touch down inside the 154 km (96 mile) wide Gale Crater on Aug. 6, 2012. The crater exhibits exposures of phyllosilicates and other minerals that may have preserved evidence of ancient or extant Martian life and is dominated by a towering 3 mile (5 km) high mountain.
“10 science instruments are all aimed at a mountain whose stratigraphic layering records the major breakpoints in the history of Mars’ environments over likely hundreds of millions of years, including those that may have been habitable for life,” Grotzinger told me.
Titan Upfront
The colorful globe of Saturn's largest moon, Titan, passes in front of the planet and its rings in this true color snapshot from NASA's Cassini spacecraft. Credit: NASA/JPL-Caltech/Space Science InstituteCuriosity Mars Science Laboratory Rover and Ken Kremer - inside the Cleanroom at the Kennedy Space Center. Last View of Curiosity just prior to folding and encapsulation for launch. Credit: Ken Kremer
This past year Ken was incredibly fortunate to witness the ongoing efforts of many of these magnificent endeavors.
Crater in Shadow on Vesta. This new image from Dawn in its low altitude mapping orbit on Dec. 13 shows part of the rim of a fresh crater on Vesta located in an area known as the Heavily Cratered Terrain in the northern hemisphere at around 17 degrees latitude and 77 degrees longitude. It was obtained at an altitude of 119 miles (191 km) and covers an area 11 mi x 11 mi (18 km x 18 km). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
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NASA’s Dawn spacecraft has swooped down to the closest orbit above the monster asteroid Vesta that the craft’s cameras and spectrometers will ever glimpse and the probe has begun transmitting these highest resolution pictures to anxiously waiting scientists back on Earth.
Dawn arrived at its Low Altitude Mapping Orbit, known as LAMO, on Dec. 12, 2011 and will continue circling scarcely 130 miles (210 kilometers) above Vesta for at least the next 10 weeks. Each orbit takes about 4.3 hours.
NASA has now released the first batch of crisp new close-ups images taken by the Framing Camera on Dec. 13 showing the stippled and lumpy surface in an exquisitely fine detail never seen before.
The photo montage below shows side by side views of the same portion of the Vestan surface at ever increasing resolution and clarity from ever lower altitudes.
Closer and Closer to the Vesta Surface
NASA’s Dawn spacecraft has spiraled closer and closer to the surface of the giant asteroid Vesta since arriving in mid-2011. The two images on the left represent an identical area, first observed during Dawn's survey orbit (far left image). The picture in the center is from Dawn's high-altitude mapping orbit (HAMO) from an altitude of about 430 miles (700 km) with about 230 feet (70 meters-per-pixel) resolution. The image at right was obtained on Dec. 13 from the low altitude mapping orbit (LAMO) at an altitude of 124 miles (199 km) above the surface and has a resolution of 75 feet (23 m) per pixel. It shows small impact craters or slumping at the steep-flanked mountain in the image center that can be identified in the two images to the left. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
The high resolution image gallery reveals fine scale highlights such as multitudes of small craters, grooves and lineaments, landslides and slumping, ejecta from past colossal impacts, and small outcrops of bright and dark materials.
The science team, led by Principal Investigator Prof Chris Russell of UCLA, believes that Vesta is actually more like a planet than an asteroid based on the data obtained thus far.
“Vesta is the smallest terrestrial planet in our Solar System”, Russell told Universe Today. “We do not have a good analog to Vesta anywhere else in the Solar System.”
The primary science objectives at the LAMO orbit are to measure the elemental abundances on the surface of Vesta with the US built gamma ray and neutron detector (GRaND) and to probe the interior structure of the asteroid by measuring the gravity field.
Vesta is a proto-planet formed just a few million years after the birth of the solar system whose evolution into a larger planet was stopped cold by the massive gravitational influence of the planet Jupiter.
Scientists are plowing through thousands of images and millions of spectral measurements to glean clues about the origin and evolution of the solar system that have been preserved on the hitherto unexplored world.
Buried Craters on Vesta
This Dec. 13 image from Dawn spacecraft in its low altitude mapping orbit shows many buried craters located within the equatorial trough region of Vesta. This area bears traces of the material thrown out by the impact that created the Rheasilvia basin in the asteroid’s south polar region. Lineated features are visible in a variety of shapes and sizes from an altitude of 117 miles (189 km) over an area of 11 mi x 11 mi (18 km x 18 km). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
“Vesta is a transitional body between a small asteroid and a planet and is unique in many ways,” says mission scientist Vishnu Reddy of the Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany. “Vesta is unlike any other asteroid we have visited so far.”
After completing the LAMO measurements, Dawn will again spiral back to a higher altitude for further data gathering especially at the unseen North Pole which is in darkness now.
Dawn will continue orbiting Vesta until July 2012 when it will fire up its ion propulsion system and depart for Ceres, the largest body in the main Asteroid belt between Mars and Jupiter.
“What can be more exciting than to explore an alien world that until recently was virtually unknown!” Dr. Marc Rayman told Universe Today. Rayman is Dawn’s Chief Engineer from NASA’s Jet Propulsion Lab (JPL) in Pasadena, Calif.
Equatorial Trough in Dark and Bright on Vesta
This image was one of the first obtained by Dawn in its low altitude mapping orbit and shows a part of one of the long troughs at the equator of Vesta. Credit: NASA/ JPL-Caltech/ UCLA/ MPS/ DLR/ IDA
“Dawn continues to gather gamma ray spectra and neutron spectra,” Rayman reports. “The bonus imaging at LAMO is yielding pictures more than three times better than those acquired in the high altitude mapping orbit (HAMO). Every week at this low altitude, Dawn will use its ion propulsion system to fine tune its orbit. The first of these weekly orbit adjustments was performed on December 17.”
The framing cameras eere built by the Max Planck Institute for Solar System Research in Germany.
A treasure trove of spectacular Vesta close-ups are streaming at this moment to the home planet and we’ll have many more goodies to show.
Holiday Greetings from an Alien Snowman on Vesta - to all inhabitants of the Galaxy
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Celebrate the winter holiday season in the company of an ‘Alien Snowman’ on the asteroid Vesta, someone we didn’t even have a clue about until six months ago.
Vesta and the Snowman have been transformed into the beautiful banner above – sent to me courtesy of the Dawn mission team to share with the readers of Universe Today.
Now you can be a creative artist and use the striking new images of Vesta to fashion your own greeting cards (see below) and send seasonal tidings of winter holiday cheer not possible before – all thanks to the remarkably insightful discoveries of Dawn’s international science team.
Vesta Greeting Card created by Joe W - From Dawn website
The Dawn spacecraft orbiting the giant asteroid Vesta is one of NASA’s crowning scientific accomplishments of 2011 because it’s cameras and spectrometers have unveiled a mysteriously diverse world that has no match elsewhere in our solar system.
The more we explore the unknown the more we are enlightened as to just how limited our view of the Universe is from within the narrow confines of our miniscule abode.
Vesta Greeting Card created by Judy C - From Dawn website
Hey, Let's go skiing at the South Pole !
The Kepler Space Telescopes latest discoveries of Earth-sized worlds are just the latest examples guiding us to a clearer understanding of our place in the Universe.
Vesta Greeting Card created by Jillian S - From Dawn website
Here are just a few of the Vestan images you can masterfully decorate – the Snowman, The Mount Everest of Vesta and the cataclysmically bombarded South Pole.
Alien Snowman on Vesta
An impact structure on asteroid Vesta resembling a snowman. Credit: NASA
So, let you imaginations run wild with wintery scenes to match the majesty of this matchless world. The Dawn Education and Public Outreach (EPO) team has created several templates which you can access here
Of course you can also use any of the images posted at the Dawn mission website.
The Mount Everest of Vesta
Image of asteroid Vesta calculated from a shape model, showing a tilted view of the topography of the south polar region. This perspective shows the topography, but removes the overall curvature of Vesta, as if the giant asteroid were flat and not rounded. Credit: NASAShattered South Pole of Vesta
This Dawn framing camera image shows scarps, hummocky (eg. wavy/ undulating) terrain and impacts in Vesta's south polar region. Credit: NASA
And feel free to post your inspired creations here at Universe Today.
Vesta is the second most massive object in the main Asteroid Belt between Mars and Jupiter.
Dawn arrived in orbit at Vesta in July 2011 for the first ever close up studies of the shattered celestial body. Dawn will spend a year investigating Vesta before spiraling out towards Ceres, the largest asteroid.
Saturn's moons Rhea and Dione as seen by the Cassini spacecraft. Could this be a future view from Earth? Image credit: NASA/JPL/Space Science Institute
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In the fall of 2006, observers at the Catalina Sky Survey in Arizona found an object orbiting the Earth. At first, it looked like a spent rocket stage — it had a spectrum similar to the titanium white paint NASA uses on rocket stages that end up in heliocentric orbits. But closer inspection revealed that the object was a natural body. Called 2006 RH120, it was a tiny asteroid measuring just a few metres across but it still qualified as a natural satellite just like the Moon. By June 2007, it was gone. Less than a year after it arrived, it left Earth’s orbit in search of a new cosmic companion.
Now, astrophysicists at Cornell are suggesting that 2006 RH120 wasn’t an anomaly; a second temporary moon is actually the norm for our planet.
Temporary satellites are a result of the gravitational pull of Earth and the Moon. Both bodies pull on one another and also pull on anything else in nearby space. The most common objects that get pulled in by the Earth-Moon system’s gravity are near Earth objects (NEOs) — comets and asteroids are nudged by the outer planets and end up in orbits that bring them into Earth’s neighbourhood.
Near Earth object Eros, the type of object that could be a second satellite. Image credit: NASA
The team from Cornell, astrophysicists Mikael Granvik, Jeremie Vaubaillon, Robert Jedicke, has modeled the way our Earth-Moon system captures these NEOs to understand how often we have additional moons and how long they stick around.
They found that the Earth-Moon system captures NEOs quite frequently. “At any given time, there should be at least one natural Earth satellite of 1-meter diameter orbiting the Earth,” the team said. These NEOs orbit the Earth for about ten months, enough time to make about three orbits, before leaving.
Luckily, and very interestingly, this discovery has implication well beyond academic applications.
Knowing that these small satellites come and go but that one is always present around the Earth, astronomers can work on detecting them. With more complete information on these bodies, specifically their position around the Earth at a given time, NASA could send a crew out to investigate. A crew wouldn’t be able to land on something a few metres across, but they could certainly study it up close and gather samples.
Close up image of asteroid 243 Ida. Image credit: NASA/courtesy of nasaimages.org
Proposals for a manned mission to an asteroid have been floating around NASA for years. Now, astronauts won’t have to go all the way out to an asteroid to learn about the Solar System’s early history. NASA can wait for an asteroid to come to us.
If the Cornell team is right and there is no shortage of second satellites around the Earth, the gains from such missions increases. The possible information about the solar system’s formation that we could obtain would be amazing, and amazingly cost-efficient.
Dawn Orbiting Vesta. This artist's concept shows NASA's Dawn spacecraft orbiting the giant asteroid Vesta. The depiction of Vesta is based on images obtained by Dawn's framing cameras. Dawn is an international collaboration of the US, Germany and Italy. Credit: NASA/JPL-Caltech
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NASA’s Dawn Asteroid Orbiter successfully spiraled down today to the closest orbit the probe will ever achieve around the giant asteroid Vesta, and has now begun critical science observations that will ultimately yield the mission’s highest resolution measurements of this spectacular body.
“What can be more exciting than to explore an alien world that until recently was virtually unknown!” Dr. Marc Rayman gushed in an exclusive interview with Universe Today. Rayman is Dawn’s Chief Engineer from NASA’s Jet Propulsion Lab (JPL) in Pasadena, Calif., and a protégé of Star Trek’s Mr. Scott.
Before Dawn, Vesta was little more than a fuzzy blob in the world’s most powerful telescopes. Vesta is the second most massive object in the main Asteroid Belt between Mars and Jupiter.
Dawn is now circling about Vesta at the lowest planned mapping orbit, dubbed LAMO for Low Altitude Mapping Orbit. The spacecraft is orbiting at an average altitude of barely 130 miles (210 kilometers) above the heavily bombarded and mysterious world that stems from the earliest eons of our solar system some 4.5 Billion years ago. Each orbit takes about 4.3 hours.
“It is both gratifying and exciting that Dawn has been performing so well,” Rayman told me.
Dawn Orbiting Over Vesta - A Hi Res Taste of What's Ahead!
This image of the giant asteroid Vesta was obtained by Dawn in the evening Nov. 27 PST (early morning Nov. 28, UTC), as it was spiraling down from its high altitude mapping orbit to low altitude mapping orbit. Low altitude mapping orbit is the closest orbit Dawn will be making, at an average of 130 miles (210 kilometers) above the giant asteroid's surface. The framing camera obtained this image of an area in the northern mid-latitudes of Vesta from an altitude of about 140 miles (230 kilometers). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA
Dawn arrived in orbit at Vesta in July 2011 after a nearly 4 year interplanetary cruise since blasting off atop a Delta II rocket from Cape Canaveral, Florida in September 2007. The probe then spent the first few weeks at an initial science survey altitude of about 1,700 miles (2,700 kilometers).
Gradually the spaceship spiraled down closer to Vesta using her ion propulsion thrusters.
See Vesta science orbit diagram, below, provided courtesy of Dr. Marc Rayman.
Along the way, the international science and engineering team commanded Dawn to make an intermediate stop this past Fall 2011 at the High Altitude Mapping orbit altitude (420 miles, or 680 kilometers).
“It is so cool now to have reached this low orbit [LAMO]. We already have a spectacular collection of images and other fascinating data on Vesta, and now we are going to gain even more,” Rayman told me.
“We have a great deal of work ahead to acquire our planned data here, and I’m looking forward to every bit!
Dawn will spend a minimum of 10 weeks acquiring data at the LAMO mapping orbit using all three onboard science instruments, provided by the US, Germany and Italy.
While the framing cameras (FC) from Germany and the Visible and Infrared Mapping spectrometer (VIR) from Italy will continue to gather mountains of data at their best resolution yet, the primary science focus of the LAMO orbit will be to collect data from the gamma ray and neutron detector (GRaND) and the gravity experiment.
GRaND will measure the elemental abundances on the surface of Vesta by studying the energy and neutron by-products that emanate from it as a result of the continuous bombardment of cosmic rays. The best data are obtained at the lowest altitude.
Dawn spacecraft - Science orbits at Vesta
Credit: NASA/JPL-Caltech/Marc Rayman
By examining all the data in context, scientists hope to obtain a better understanding of the formation and evolution of the early solar system.
Vesta is a proto-planet, largely unchanged since its formation, and whose evolution into a larger planet was stopped cold by the massive gravitational influence of the planet Jupiter.
“Dawn’s visit to Vesta has been eye-opening so far, showing us troughs and peaks that telescopes only hinted at,” said Christopher Russell, Dawn’s principal investigator, based at UCLA. “It whets the appetite for a day when human explorers can see the wonders of asteroids for themselves.”
After investigating Vesta for about a year, the engineers will ignite Dawn’s ion propulsion thrusters and blast away to Ceres, the largest asteroid which may harbor water ice and is another potential outpost for extraterrestrial life
Dawn will be the first spaceship to orbit two worlds and is also the first mission to study the asteroid belt in detail.
Asteroid Vesta from Dawn - Exquisite Clarity from a formerly Fuzzy Blob
NASA's Dawn spacecraft obtained this image of the giant asteroid Vesta with its framing camera on July 24, 2011. It was taken from a distance of about 3,200 miles (5,200 kilometers). Before Dawn, Vesta was just a fuzzy blob in the most powerful telescopes. Dawn entered orbit around Vesta on July 15, and will spend a year orbiting the body before firing up the ion propulsion system to break orbit and speed to Ceres, the largest Asteroid. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDASouth Polar Region of Vesta - Enhanced View
An ancient cosmic collision blasted away much of the south pole of Vesta, leaving behind an enoumous mountain about 3 times the height of Mt. Everest. NASA's Dawn spacecraft obtained this image centered on the south pole of Vesta with its framing camera on July 18, 2011 as it passed the terminator. The image has been enhanced to bring out more surface details. It was taken from a distance of about 6,500 miles (10,500 kilometers) away from the protoplanet Vesta. The smallest detail visible is about 1.2 miles (2.0 km). Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. Enhanced and annotated by Ken Kremer
Read continuing features about Dawn by Ken Kremer starting here:
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It’s the finale of this year’s meteor showers: The Geminids will start appearing on Dec. 7 and should reach peak activity around the 13th and 14th. This shower could put on a display of up to 100+ meteors (shooting stars) per hour under good viewing conditions.
However, conditions this year are not ideal with the presence of a waning gibbous Moon (which will be up from mid-evening until morning). But seeing meteors every few minutes is quite possible. Geminid meteors are often slow and bright with persistent coloured trails which can linger for a while after the meteor has burned up.
There is something unusual about the Geminid meteor shower, as normally meteor showers are caused by the Earth ploughing through the debris streams created by comets and their tails. But the object that created the specific stream of debris associated with the Geminids is not a dusty icy comet, but a rocky asteroid called Phaethon 3200.
Phaethon 3200 belongs to a group of asteroids whose orbit cross the Earth’s. It turns out to be an unusual member of that group: Not only does it pass closer to the Sun than the others but it also has a different colour, suggesting a different composition to most asteroids. Credit: Adrian West
One of the curious things about the Geminid particles is that they are more solid than meteoroids known to come from comets. This is good for meteor watchers; giving us brighter meteors.
Observations by astronomers over decades have shown that meteor rates have increased as we reach denser parts of the stream.
It is not known exactly when the asteroid was deflected into its current orbit, but if it was originally a comet it would have taken a long time for all the ices to have been lost. However, it is possible that it may have been a stony asteroid with pockets of ice.
We are unsure of the origins and appearance of Phaethon 3200, but its orbit has left us with a unique legacy every December, with little steaks of light known as the Geminid meteor shower.
You will only need your eyes to watch the meteor shower, you do not need telescopes binoculars etc, but you will need to be patient and comfortable. See this handy guide on how to observe meteors
During a meteor shower, meteors originate from a point in the sky called the radiant and this gives rise to the showers name e.g. The Geminids radiant is in Gemini, Perseids radiant is in Perseus etc.
Don’t be mislead by thinking you have to look in a particular part of or direction of the sky, as meteors will appear anywhere and will do so at random. You will notice that if you trace back their path or trajectory it will bring you to the meteor showers radiant. The exception to this rule is when you see a sporadic or rogue meteor.
Tell your friends, tell your familly and tell everyone to look up and join in with the Geminid meteorwatch on the 12th to the 14th December 2011. Use the #meteorwatch hashtag on twitter and visit meteorwatch.org for tips and guides on how to see and enjoy the Geminids and other meteor showers. Credit: Wally Pacholka
