Jupiter, the largest and most massive planet in our solar system, may be its own worst enemy. It turns out that its central core may in fact be self-destructing, gradually liquifying and dissolving over time. This implies it was previously larger than it is now, and may dissolve altogether at some point in the future. Will Jupiter eventually destroy itself completely? No, probably not, but it may lose its heart…
The core is composed of iron, rock and ice and weighs about ten times as much as Earth. That’s still small though, compared to the overall mass of Jupiter itself, which weighs as much as 318 Earths! The core is buried deep within the thick atmosphere of hydrogen and helium. Conditions there are brutal, with a temperature of about 16,000 kelvin – hotter than the surface of the Sun – and a pressure about 40 million times greater than the atmospheric pressure on Earth. The core is surrounded by a fluid of metallic hydrogen which results from the intense pressure deep down in the atmosphere. The bulk of Jupiter though is the atmosphere itself, hence why Jupiter (and Saturn, Uranus and Neptune) are called gas giants.
One of the primary ingredients in the rock of the core is magnesium oxide (MgO). Planetary scientists wanted to see what would happen when it is subjected to the conditions found at the core; they found that it had a high solubility and started to dissolve. So if it is in a state of dissolution, then it was probably larger in the past than it is now and scientists would like to understand the process. According to David Stevenson of the California Institute of Technology, “If we can do that, then we can make a very useful statement about what Jupiter was like at genesis. Did it have a substantial core at that time? If so, was it 10 Earth masses, 15, 5?”
The findings also mean that some exoplanets which are even larger and more massive than Jupiter, and thus likely even hotter at their cores, may no longer have any cores left at all. They would be indeed be gas giants in the most literal sense.
The conditions inside Jupiter’s core can’t be duplicated in labs yet, but the spacecraft Juno should provide much more data when it arrives at and starts orbiting Jupiter in 2016.
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:
The Voyager 1 spacecraft has started to transverse what JPL has dubbed as a "cosmic purgatory" between our solar system - and interstellar space. Image Credit: NASA/JPL
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Voyager 1 is in uncharted territory. The long-lived spacecraft has entered a new region of space that lies between where our solar system ends and where interstellar space begins. This area is not a place of sightseeing however, as a NASA press release referred to it as a kind of “cosmic purgatory.”
Here, the solar winds ebb somewhat, the magnetic field increases and charged particles from within our solar system – is leaking out into interstellar space. This data has been compiled from information received from Voyager 1 over the course of the last year.
The Voyager spacecraft's compliment of scientific instruments have provided scientists back on Earth with information about what the space environment at the fringes of our sun's influence is truly like. Image Credit: NASA/JPL - Caltech
“Voyager tells us now that we’re in a stagnation region in the outermost layer of the bubble around our solar system,” said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. “Voyager is showing that what is outside is pushing back. We shouldn’t have long to wait to find out what the space between stars is really like.”
Despite the fact that Voyager 1 is approximately 11 billion miles (18 billion kilometers) distant from the sun – it still has not encounter interstellar space. The information that scientists have gleaned from the Voyager 1 spacecraft indicates that the spacecraft is still located within the heliosphere. The heliosphere is a “bubble” of charged particles that the sun blows around itself and its retinue of planets.
Voyager 1 has traveled far past the realm of the gas or even ice giants and is now in uncharted territory where scientists are learning more and more about the dynamic environment at the far-flung edges of our solar system. Image Credit: NASA/JPL - Caltech
The latest findings were made using Voyager’s Low Energy Charged Particle instrument, Cosmic Ray Subsystem and Magnetometer.
Experts are not certain how long it will take the Voyager 1 spacecraft to finally breach this bubble and head out into interstellar space. Best estimates place the length of time when this could happen anywhere from the next few months – to years. These findings counter findings announced in April of 2010 that showed that Voyager 1 had essentially crossed the heliosphere boundary. The discoveries made during the past year hint that this region of space is far more dynamic than previously thought.
Voyager 1 has entered into a region of space between the sun's influence and the beginning of interstellar space that NASA has dubbed the "stagnation region." Image Credit: NASA/JPL - Caltech
The magnetometer aboard Voyager 1 has picked up an increase in the intensity of the magnetic field located within this “stagnation field.” Essentially the inward pressure from interstellar space is compressing the magnetic field to twice its original density. The spacecraft has also detected a 100-fold increase in the intensity of high-energy electrons diffusing into our solar system from outside – this is yet another indicator that Voyager 1 is approaching the heliosphere.
The interplanetary probe was launched from Cape Canaveral Air Force Station’s Space Launch Complex 41 (SLC-41) on Sept. 5, 1977, Voyager 1’s sister ship, Voyager 2 is also in good health and is about 9 billion miles (15 billion kilometers) from the sun (it too was launched in 1977). The spacecraft itself was built by NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
“Voyager is a mission of discovery and it’s at the edge of the solar system still making discoveries,” said Stone said. “The stagnation is the latest in the whole journey of discovery. We are all excited because we believe it means we’re getting very close to boundary of heliosphere and the entry into interstellar space.”
Both of the Voyager spacecraft were thrust to orbit by the powerful Titan boosters - and both in the same year - 1977. Photo Credit: NASA
Jupiter has been putting on quite a show in the night sky lately as it officially reached opposition on October 28, 2011, making it a target of many astrophotographers as the gas giant shows itself off big and bright in the night sky. This animation from amateur astronomer Leonard E. Mercer from Malta shows Jupiter’s famous Great Red Spot moving across the surface of the mighty planet. Mercer captured a series of 12 images on the 27th and 28th (10pm – 2.00am. CET). Mercer used a C11 telescope and DMK 21 mono camera with RGB filters. “Conditions were very good!” he said.
Opposition means an the planet is directly opposite the Sun as seen from Earth, which also put it at its closest point to Earth in the two planets’ orbits around the Sun.
The Space Shuttle: Celebating Thirty Years Of NASA's First Space Plane is chocked full of great imagery and works to cover each of the shuttle's 135 missions. Photo Credit: Zenith Press
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The space shuttle program is over. The orbiters are being decommissioned, stripped of the components that allowed them to travel in space. For those that followed the program, those that wished they did and those with only a passing interest in what the program accomplished a new book has been produced covering the entirety of the thirty years that comprised NASA’s longest human space flight program. The Space Shuttle: Celebrating Thirty Years of NASA’s First Space Plane is written by aerospace author Piers Bizony and weighs in at 300 pages in length.
Bizony is a prolific author who has focused a lot of his work on space flight. Some of the books that he has written include (but definitely are not limited to) include: One Giant Leap: Apollo 11 Remembered, Space 50, The Man Who Ran the Moon: James E. Webb, NASA, and the Secret History of Project Apollo and Island in the Sky: The International Space Station.
Bizony pulls out all the stops in detailing the shuttle era. From thunder and light - to tragedy, the full spectrum of the shuttle program is highlighted here. Photo Credit: NASA
The book contains 900 color images, detailing the entire history of NASA’s fleet of orbiters. From the first launches and the hope that those initial flights were rich in, to the Challenger tragedy and the subsequent realization that the space shuttles would never be what they were intended to be.
The next phase of the book deals with the post-Challenger period and how NASA worked to find a balance with its fleet of orbiters, while at the same time worked to regain the trust of the America public. The path was both hindered and helped by a single payload – the Hubble Space Telescope.
The Space Shuttle: Celebrating Thirty Years of NASA’s First Space Plane - has stunning imagery on every page, allowing the reader to once again view the majesty that the shuttle program provided. Photo Credit: NASA
When the images the orbiting telescope beamed back turned out fuzzy, NASA was a laughing stock. Hubble would become a sensation and NASA redeemed its name after the first servicing mission to Hubble corrected the problem with the telescope’s mirror.
Hubble was not the only telescope or probe that the shuttle placed in the heavens. It would however, be the only one that NASA’s fleet of orbiters would visit during several servicing missions. Besides Hubble the shuttle also sent the Chandra X-Ray telescope, Galileo probe to Jupiter and the Magellan probe to Venus during the course of the program’s history.
It is currently unknown when the U.S. will launch crews into orbit again. Some aerospace experts have even suggested that the shuttles be pulled out of retirement to help fill this gap - but this is highly unlikely to happen. Photo Credit: NASA
NASA was now on course to begin construction of the most ambitious engineering feat in human history – the International Space Station. The Space Shuttle: Celebrating Thirty Years of NASA’s First Space Plane details this period, as well as the tragic loss of the shuttle Columbia in 2003 with great care and attention to detail. Many never-before-seen images are contained within and Bizony uses them to punctuate the history that the space shuttle accomplished with every flight.
With a chance of catastrophic failure estimated by some as being as high as one chance in 53 - the shuttle was a risky endeavor. However, given all of the program's accomplishments - it is not a stretch to say that the shuttle made fact out of last century's science fiction. Photo Credit: NASA
The book also contains a detailed diagram of the orbiter (it is long and therefore was produced as a pull-out section. This element is included near the end and acts as a nice punctuation mark to the stream of imagery contained within.
While it required the combined effort of 16 different nations to make the International Space Station work - the space shuttle made the orbiting laboratory a reality. Photo Credit: NASA
The book is not perfect (but what book is). If one did not know better, upon reading this book one would assume that the Delta Clipper (both DC-X and DC-XA) flew once and upon landing caught fire. DC-X flew eight times – not once. Bizony also describes the lunar element of the Vision for Space Exploration (VSE) as being a repeat of Apollo. Apollo 17 was the longest duration that astronauts roamed the Moon’s surface – they were there for about three days. The VSE called for a permanent crewed presence on the moon.
For those out there that consider themselves “shuttle huggers” this book is simply a must-have. It is perfect to take to autograph shows to be signed by astronauts (as every mission is detailed, it is a simple matter to have crew members sign on the pages that contain their missions). It is also a perfect gift for space aficionados this holiday season. Published by Zenith Press and retailing for $40.00, The Space Shuttle: Celebrating Thirty Years of NASA’s First Space Plane is a welcome addition to your home library.
How will the shuttle be remebered? According to Bizony, given the technological restraints and the numerous accomplishments that the orbiter accomplished - it will be remembered in a positive light. Photo Credit: NASA
Have you seen a very bright star rising in the East every night the past few months? If you’re a night owl, you may have noticed it moves across they sky from the East into the West, shining brightly throughout the night. However this object is not a star! It’s the planet Jupiter and it is the brightest object in the night sky at the moment, apart from the Moon.
At the end of October Jupiter will be at opposition. This means the mighty planet (the largest in our solar system) will be directly opposite the sun as seen from Earth and it will also be at its closest point to Earth in the two planets’ orbits around the Sun. This makes Jupiter or any other object at opposition appear brighter and larger. The opposition of Jupiter occurs on October 29, 2011.
But Jupiter has been gracing our night sky for several months, and will continue to shine brightly as it moves in and out of opposition. But enjoy the view now, as this will be the closest opposition until 2022!
Visually, even with the naked eye, Jupiter is stunning! A burning yellowish-white star-like object, many times brighter than any other stars.
But through a pair of ordinary binoculars or a small telescope, Jupiter comes to life. Not only is it possible to see the disc of the Planet, you can also see the four Galilean moons.
The Galilean moons, Callisto, Ganymede, Europa and Io were discovered by Galileo over 400 years ago and are amazing worlds in their own right.
Callisto is the outermost moon with a very ancient and heavily cratered surface. It is the second largest of the four moons, but does not interact tidally with an “orbital resonance” unlike the other three moons. Callisto. Image credit: NASA/JPL
Ganymede is the largest of the four moons and is also the largest moon in the Solar system, being larger than the Planet Mercury. The bizarre surface is a mix of two types of terrain – highly cratered dark regions and younger, but still ancient regions with a large array of grooves and ridges. Ganymede is the only moon in the solar system to have its own magnetosphere.
Ganymede Credit: NASA
Europa is the second closest moon and is also the smallest. It has one of the smoothest and newest surfaces in the solar system, being covered purely with ice. Europa is likely a water world and it is believed that below its icy surface, lies a deep moon-wide ocean surrounding a warm mantle. It is one of the most likely places to harbour life in the solar system.
Europa from Galileo
Io is the innermost of the four Galilean moons of Jupiter and third largest. It is the most geologically active body in the solar system with over 400 active volcanoes and an ever changing and hostile surface of sulphur and silicates.
Io Credit: NASA
When you look up tonight and stare at Jupiter, or you are looking at it through binoculars or a telescope, just think – Jupiter and the four Galilean moons are a very interesting place, almost a mini solar system with our larger solar system!
Occasionally you will see Jupiter’s “Great Red Spot” or the shadow of one of the moons on Jupiter’s surface. The Jupiter system is always changing.
If you want to find out what the positions are for the moons, use planetarium software such as Stellarium and then have a look yourself.
Dr. Ed Weiler retired on Sept 30, 2011 as the NASA Associate Administrator for the Science Mission Directorate at NASA HQ, Washington, DC after 33 distinguished years at NASA, including 10 years as Chief of all NASA Space Science and nearly 20 years as Chief Scientist for the Hubble Space Telescope. In this photo, Weiler ‘Hugs Hubble' after launch of STS-125 on the final shuttle mission to repair and upgrade the Hubble Space Telescope in May 2009. A happy and relieved Weiler chats post-launch inside the KSC Press Center about Hubble and NASA Space Science. Credit: Ken Kremer
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Ed Weiler, NASA’s Science leader in charge of the robotic missions that continually produce scientific breakthroughs that amaze all humanity and longtime Chief Scientist on the Hubble Space Telescope that has completely revolutionized our understanding of humanities place in the Universe, retired today (Sept. 30) from NASA after a distinguished career spanning almost 33 years.
Weiler is departing NASA during what has been dubbed the “Year of Space Science”- the best year ever for NASA Space Science research. The two most recent successes are the launch of JUNO to Jupiter and the twin GRAIL probes to the Moon. Blastoff of the Curiosity Mars Science Laboratory rover is slated for late November 2011.
Weiler’s official title is associate administrator of NASA’s Science Mission Directorate (SMD) at agency Headquarters in Washington, DC. In that capacity he was responsible for overseeing NASA’s science and research programs in Earth science, heliophysics, planetary science and astrophysics.
Weiler was appointed to lead SMD in 2008. He holds this position now for the second time after serving in between as Director of NASA Goddard Spaceflight Center in Greenbelt, Maryland from 2004 to 2008. His earlier stint as associate administrator lasted from 1998 to 2004 for what was then called the Space Science Enterprise.
Dr. Ed Weiler, NASA Associate Administrator for the Science Mission Directorate. Credit: NASA/Bill Ingalls
Probably the job he loved best was as Chief Scientist of the Hubble Space Telescope from 1979 to 1998, until he was promoted to the top rung of NASA management.
I was very lucky to meet and chat with Ed Weiler while I was covering the final space shuttle flight – STS-125 – to repair and upgrade Hubble. STS 125 blasted off in May 2009 and accomplished every single objective to catapult Hubble to the apex of its capabilities.
At the recent launch of the twin GRAIL lunar mapping probes, I spoke with Weiler about a wide range of NASA missions. Watch for my upcoming interview with Ed.
Weiler is very hopeful that Hubble will continue to operate for several more years at least.
NASA issued this statement from NASA Administrator Charles Bolden, “Ed leaves an enduring legacy of pride and success that forever will remain a part of NASA’s science history. His leadership helped inspire the public with each new scientific discovery, and enabled NASA to move forward with new capabilities to continue to explore our solar system and beyond.”
The successes under Weiler’s leadership include NASA’s great observatory missions, unprecedented advances in Earth science and extensive exploration of Mars and other planets in our solar system. These advances have rewritten science textbooks and earned enormous support for NASA’s science programs from the general public.
The Mars rovers Spirit and Opportunity are just one example of the science missions approved and funded during Weiler’s tenure.
Weiler’s leadership has been instrumental in securing continued support and funding for NASA Space Science from Congress and the White House. He has received numerous prestigious awards including the NASA Distinguished Service Medal and several Presidential Rank Awards for Meritorious Executive and Distinguished Executive.
Ed Weiler remembers Spirit at JPL symposium. Credit: AP
Earth & Moon Portrait - First Photo transmitted from Jupiter Bound Juno. This image of Earth (on the left) and the moon (on the right) was taken by NASA's Juno spacecraft on Aug. 26, 2011, when the spacecraft was about 6 million miles (9.66 million kilometers) away. It was taken by the spacecraft's onboard camera, JunoCam. Credit: NASA/JPL-Caltech
Juno lifted off 25 days ago at 12: 25 p.m. on August 5 from Space Launch Complex 41 at Cape Canaveral Air Force Station in Florida. The spacecraft snapped the portrait with the onboard JunoCam camera on August 26 after journeying some 6 million miles (9.66 million km) from Earth and while traveling at a velocity of 77,600 miles per hour (124,900 kilometers per hour) relative to the sun.
“The image of the Earth Moon system is a rather unique perspective that we can get only by stepping outside of our home planet,” said Scott Bolton, Juno principal investigator, in an exclusive interview with Universe Today. Bolton is from the Southwest Research Institute in San Antonio.
“On our way to Jupiter, we’ve looked back at home and managed to take this amazing image.”
“Earth looking much like any other planet or star from a distance is glorious as this somewhat average looking “star” is home to all of humanity. Our companion, the moon, so beautiful and important to us, stands out even less.”
“We appear almost average and inconspicuous, yet all of our history originates here. It makes one wonder just how many other planets or solar systems might contain life like ours,” Bolton told me.
Juno casts a shadow back toward Earth and Space Shuttle Launch Pad 39A and the shuttle crawler way (at left) seconds after liftoff from adjacent Launch Pad 41 at Cape Canaveral, Florida. View from the VAB Roof. Credit: Ken Kremer
The Juno team commanded the probe to take the image as part of the checkout phase of the vehicles instruments and subsystems.
“The JunoCam instrument turn on and check out were planned activities. The instrument is working great and in fact, all the instruments that we’ve turned on thus far have been working great,” Bolton added.
So far the spacecraft is in excellent health and the team has completed the checkout of the Waves instrument and its two Flux Gate Magnetometer sensors and deployment of its V-shaped electric dipole antenna.
“We have a couple more instruments still to do,” Bolton noted.
The team reports that Juno also performed its first precession, or reorientation maneuver, using its thrusters and that the first trajectory control maneuver (TCM-1) was cancelled as unnecessary because of the extremely accurate targeting provided by the Atlas V rocket.
The portrait shot is actually not Juno’s last photo of her home.
The 8000 pound (3,600 kilogram) probe will fly by Earth once more on October 9, 2013 for a gravity assisted speed boost of 16,330 MPH (7.3 km/sec) to accelerate Juno past the asteroid belt on its long journey to the Jovian system.
Juno soars skyward to Jupiter on Aug. 5 from launch pad 41 at Cape Canaveral Air Force Station at 12:25 p.m. EDT. View from the VAB roof. Credit: Ken Kremer
JunoCam will collect new photos and the other science instruments will make measurements as Juno cartwheels past Earth during the slingshot to Jupiter.
Juno is on a 5 year and 1.7 Billion mile (2.8 Billion km) trek to the largest planet in our solar system. When she arrives at Jupiter on July 4, 2016, Juno will become the first polar orbiting spacecraft at the gas giant.
During a one year science mission – entailing 33 orbits lasting 11 days each – the probe will plunge to within about 3000 miles (5000 km) of the turbulent cloud tops and collect unprecedented new data that will unveil the hidden inner secrets of Jupiter’s genesis and evolution.
The goal is to find out more about the planets origins, interior structure and atmosphere, observe the aurora, map the intense magnetic field and investigate the existence of a solid planetary core.
“This is a remarkable sight people get to see all too rarely,” said Bolton in a NASA statement about the Earth-Moon photo. “This view of our planet shows how Earth looks from the outside, illustrating a special perspective of our role and place in the universe. We see a humbling yet beautiful view of ourselves.”
NASA’s Jet Propulsion Laboratory manages the Juno mission. The spacecraft was designed and built by Lockheed Martin Space Systems, Denver.
Juno and Booster Streak Across the Stars
NASA's Juno spacecraft and its spent Centaur upper rocket stage are captured in this telescope view as they move across the field of stars. The five-minute, timed exposure was acquired on Aug. 5 11:18pm Eastern time (Aug. 6 at 3:18 UTC) when Juno was at a distance of about 195,000 miles (314,000 kilometers) from Earth. The images were taken remotely by amateur astronomer Scott Ferguson using Global Rent-a-Scope's GRAS-016 Takahashi Widefield Refractor, which is located in Nerpio, Spain. Credit: Scott FergusonJuno Spacecraft Cruise Trajectory to Jupiter
This graphic shows Juno's trajectory, or flight path, from Earth to Jupiter. The spacecraft travels around the Sun, to a point beyond the orbit of Mars where it fires its main engine a couple of times. These deep space maneuvers set up the Earth flyby maneuver that occurs approximately two years after launch. The Earth flyby gives Juno the boost in velocity it needs to coast all the way to Jupiter. Juno arrives at Jupiter in July 2016. Credit: NASA/JPL-CaltechView of Juno’s position on Aug. 24, 2011 nearly 6 million miles distant from Earth visualized by NASA’s Eyes on the Solar System website.
Shortly after forming, Jupiter was slowly pulled toward the sun. Saturn was also pulled in and eventually, their fates became linked. When Jupiter was about where Mars is now, the pair turned and moved away from the sun. Scientists have referred to this as the "Grand Tack," a reference to the sailing maneuver. Credit: NASA/GSFC
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Jupiter hasn’t always been in the same place in our solar system. Early in the history of our solar system, Jupiter moved inward towards the sun, almost to where Mars currently orbits now, and then back out to its current position.
The migration through our solar system of Jupiter had some major effects on our solar system. Some of the effects of Jupiter’s wanderings include effects on the asteroid belt and the stunted growth of Mars.
What other effects did Jupiter’s migration have on the early solar system and how did scientists make this discovery?
In a research paper published in the July 14th issue of Nature, First author Kevin Walsh and his team created a model of the early solar system which helps explain Jupiter’s migration. The team’s model shows that Jupiter formed at a distance of around 3.5 A.U (Jupiter is currently just over 5 A.U from the sun) and was pulled inward by currents in the gas clouds that still surrounded the sun at the time. Over time, Jupiter moved inward slowly, nearly reaching the same distance from the sun as the current orbit of Mars, which hadn’t formed yet.
“We theorize that Jupiter stopped migrating toward the sun because of Saturn,” said Avi Mandell, one of the paper’s co-authors. The team’s data showed that Jupiter and Saturn both migrated inward and then outward. In the case of Jupiter, the gas giant settled into its current orbit at just over 5 a.u. Saturn ended its initial outward movement at around 7 A.U, but later moved even further to its current position around 9.5 A.U.
Astronomers have had long-standing questions regarding the mixed composition of the asteroid belt, which includes rocky and icy bodies. One other puzzle of our solar system’s evolution is what caused Mars to not develop to a size comparable to Earth or Venus.
Artist's conception of early planetary formation from gas and dust around a young star. Image Credit: NASA/JPL-Caltech
Regarding the asteroid belt, Mandell explained, “Jupiter’s migration process was slow, so when it neared the asteroid belt, it was not a violent collision but more of a do-si-do, with Jupiter deflecting the objects and essentially switching places with the asteroid belt.”
Jupiter’s slow movement caused more of a gentle “nudging” of the asteroid belt when it passed through on its inward movement. When Jupiter moved back outward, the planet moved past the location it originally formed. One side-effect of caused by Jupiter moving further out from its original formation area is that it entered the region of our early solar system where icy objects were. Jupiter pushed many of the icy objects inward towards the sun, causing them to end up in the asteroid belt.
“With the Grand Tack model, we actually set out to explain the formation of a small Mars, and in doing so, we had to account for the asteroid belt,” said Walsh. “To our surprise, the model’s explanation of the asteroid belt became one of the nicest results and helps us understand that region better than we did before.”
With regards to Mars, in theory Mars should have had a larger supply gas and dust, having formed further from the sun than Earth. If the model Walsh and his team developed is correct, Jupiter foray into the inner solar system would have scattered the material around 1.5 A.U.
Mandell added, “Why Mars is so small has been the unsolvable problem in the formation of our solar system. It was the team’s initial motivation for developing a new model of the formation of the solar system.”
An interesting scenario unfolds with Jupiter scattering material between 1 and 1.5 AU. Instead of the higher concentration of planet-building materials being further out, the high concentration led to Earth and Venus forming in a material-rich region.
The model Walsh and his team developed brings new insight into the relationship between the inner planets, our asteroid belt and Jupiter. The knowledge learned not only will allow scientists to better understand our solar system, but helps explain the formation of planets in other star systems. Walsh also mentioned, “Knowing that our own planets moved around a lot in the past makes our solar system much more like our neighbors than we previously thought. We’re not an outlier anymore.”
Universe Today: The Juno mission just launched to Jupiter and there are lots of other space missions going on. What are some your favorites and your hopes of what those kinds of missions will discover?
Brian Cox: The enormous question for space exploration is origin of life on other worlds. That is currently THE big question. We’ve seen discoveries recently about possible, plausible evidence of flowing water on Mars. There’s been evidence for awhile that there is perhaps subsurface water, but seeing what looks to be the signature of flowing, briny water — today — is very suggestive. On Earth, where we have water we have life, so this new finding makes Mars even more fascinating. The ExoMars project, the joint European-American mission to Mars to look for life is going to be one of most exciting missions yet, because there’s a good chance of finding it.
The ExoMars/Trace Gas Orbiter mission is a joint mission being developed by the European Space Agency (ESA) and NASA/JPL. This mission would be the first in a series of joint missions to Mars for ESA and NASA. Credit: NASA
Now we’re heading off to Jupiter, and Europa is actually a fascinating place for the same reason. There is a huge amount subsurface water on Europa, and there has been speculation that colored markings on the surface of Europa could be life. It looks as though there may be seasonal shifts, and that could be possible cyanobacteria in the ice. This is really speculative, but this is the kind of language people are using now, talking about finding life with real optimism.
Beyond the solar system, the search for exoplanets is going very, very well. Virtually every star we survey we find planets! Well, that might be a bit of an exaggeration, but we’ve found hundreds and hundreds of planets. We’ve begun to see Earth-like planets and so the next step is to do spectroscopy to look at light passing through the atmospheres of those planets and look for signatures of elements like oxygen. Again, if you find oxygen-rich atmospheres — which we are on the verge of looking for now — if you find that, then you’ve got pretty good evidence there is life on those planets.
So, it could be we find life on a distant planet before we find life in the solar system, which would be tremendous. But really, I do think the big discoveries will be all about life, certainly in solar system exploration.
UT : What are your hopes for the future regarding physics, technology and space?
Large Hadron Collider (CERN/LHC/GridPP)
COX: I’d like to see an increase in rational thinking, which is synonymous with
scientific thinking.
Scientifically, the Large Hadron Collider is going to make a huge difference. It really is going to revolutionize our fundamental understanding of the way the universe works. Then there are these huge questions in fundamental physics, the question of why gravity is so weak, why the universe began in such an ordered way.
Then, what is 96% of the Universe made of? We know our Universe is full of something called Dark Matter and we don’t know what it is. The Universe is accelerating in its expansion, which we call Dark Energy and we don’t know what that is either. There is something fundamental going on.
I’d like to think this period of time is like the period of 1890 onwards to the turn of the 20th century. There were some small problems with things like understanding the spectrum of light, what atoms were; little problems really. But when we finally understood, it revolutionized our understanding of the Universe. Shortly after the turn of the century we got quantum theory, relativity – a complete change in our understanding. I’d like to think that maybe it’s a bit like that at the moment. There are so many little — and big — chinks in the armor of our picture of the Universe at the fundamental level. I think within the next few years, there will be big shifts, and probably, they will be led by the data from the LHC.
