Posted on by Nancy Atkinson

It’s Official: Juno is Going to Jupiter

Juno's payload. Image Credit: NASA
Juno's payload. Image Credit: NASA

NASA has decided to return to Jupiter with a mission to conduct an unprecedented, in-depth study of the largest planet in our solar system. The mission is called Juno, and it will be the first in which a spacecraft is placed in a highly elliptical polar orbit around the giant planet to understand its formation, evolution and structure. Missions to Jupiter have been on again, off again, with a mission to Europa falling during the 2006 budget cuts, and the Jupiter Icy Moons Orbiter (which would have used a nuclear reactor to power an ion engine to send an orbiter to 3 of Jupiter’s moons) getting the ax in 2005. Juno has been on the table since 2004, surviving budget cuts, although the mission has experienced delays. But it looks official now, and the spacecraft is scheduled to launch in August 2011, reaching Jupiter in 2016.

Scientists say studying Jupiter is important because it hold secrets to the fundamental processes and conditions that governed our early solar system. “Jupiter is the archetype of giant planets in our solar system and formed very early, capturing most of the material left after the sun formed,” said Scott Bolton, Juno principal investigator from the Southwest Research Institute in San Antonio. “Unlike Earth, Jupiter’s giant mass allowed it to hold onto its original composition, providing us with a way of tracing our solar system’s history.”

The spacecraft will orbit Jupiter 32 times, skimming about 3,000 miles over the planet’s cloud tops for approximately one year. The mission will be the first solar powered spacecraft designed to operate despite the great distance from the sun.

Artists concept of Juno at Jupiter. Credit: NASA
Artists concept of Juno at Jupiter. Credit: NASA

“Jupiter is more than 400 million miles from the sun or five times further than Earth,” Bolton said. “Juno is engineered to be extremely energy efficient.”

The spacecraft will use a camera and nine science instruments to study the hidden world beneath Jupiter’s colorful clouds. The suite of science instruments will investigate the existence of an ice-rock core, Jupiter’s intense magnetic field, water and ammonia clouds in the deep atmosphere, and explore the planet’s aurora borealis.

Understanding the formation of Jupiter is essential to understanding the processes that led to the development of the rest of our solar system and what the conditions were that led to Earth and humankind. Similar to the sun, Jupiter is composed mostly of hydrogen and helium. A small percentage of the planet is composed of heavier elements. However, Jupiter has a larger percentage of these heavier elements than the sun.

“Juno gives us a fantastic opportunity to get a picture of the structure of Jupiter in a way never before possible,” said James Green, director of NASA’s Planetary Division at NASA Headquarters in Washington. “It will allow us to take a giant step forward in our understanding on how giant planets form and the role that plays in putting the rest of the solar system together. ”

The last mission to Jupiter was the Galileo mission, which began its observations of the giant planet in 1995, made 35 orbits, and then was intentionally flown into the planet in 2003 to avoid any contamination of Jupiter’s moons.

Source: NASA

Posted on by Nancy Atkinson

Best Ground-Based Image of Jupiter — Ever!

Jupiter from the VLT. Credit: ESO

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Everyone loves twinkling stars and moonlit nights—EXCEPT astronomers. But astronomers are crafty people, so they’ve come up with ways to mitigate the distortion that Earth’s thick atmosphere causes for ground based telescopes (from which stars appear to twinkle). And now, a new image-correction technique has delivered the sharpest whole-planet ground-based picture ever. The Very Large Telescope (VLT) performed a record two-hour observation of Jupiter using a breakthrough technique to remove atmospheric blur. And what a result! Just take a look at that gorgeous image…And this new image reveals changes in Jupiter’s smog-like haze, probably in response to a planet-wide upheaval more than a year ago.

Being able to correct wide field images for atmospheric distortions has been the dream of scientists and engineers for decades. Astronomers used a new device called the Multi-Conjugate Adaptive Optics Demonstrator (MAD) prototype instrument mounted on ESO’s Very Large Telescope (VLT)
The new images of Jupiter prove the value of the advanced technology used by MAD, which uses two or more guide stars instead of one as references to remove the blur caused by atmospheric turbulence over a field of view thirty times larger than existing techniques.

“This type of adaptive optics has a big advantage for looking at large objects, such as planets, star clusters or nebulae,” says lead researcher Franck Marchis, from UC Berkeley and the SETI Institute in Mountain View, California, USA. “While regular adaptive optics provides excellent correction in a small field of view, MAD provides good correction over a larger area of sky. And in fact, were it not for MAD, we would not have been able to perform these amazing observations.”

MAD allowed the researchers to observe Jupiter for almost two hours on 16 and 17 August 2008, a record duration, according to the observing team. They were able to take a series of 265 snapshots. Conventional adaptive optics systems using a single Jupiter moon as reference cannot monitor Jupiter for so long because the moon moves too far from the planet. The Hubble Space Telescope cannot observe Jupiter continuously for more than about 50 minutes, because its view is regularly blocked by the Earth during Hubble’s 96-minute orbit.

Using MAD, ESO astronomer Paola Amico, MAD project manager Enrico Marchetti and Sébastien Tordo from the MAD team tracked two of Jupiter’s largest moons, Europa and Io – one on each side of the planet – to provide a good correction across the full disc of the planet. “It was the most challenging observation we performed with MAD, because we had to track with high accuracy two moons moving at different speeds, while simultaneously chasing Jupiter,” says Marchetti.

With this unique series of images, the team found a major alteration in the brightness of the equatorial haze, which lies in a 16,000-kilometer wide belt over Jupiter’s equator. More sunlight reflecting off upper atmospheric haze means that the amount of haze has increased, or that it has moved up to higher altitudes. “The brightest portion had shifted south by more than 6,000 kilometers,” explains team member Mike Wong.

This conclusion came after comparison with images taken in 2005 by Wong and colleague Imke de Pater using the Hubble Space Telescope. The Hubble images, taken at infrared wavelengths very close to those used for the VLT study, show more haze in the northern half of the bright Equatorial Zone, while the 2008 VLT images show a clear shift to the south.

“The change we see in the haze could be related to big changes in cloud patterns associated with last year’s planet-wide upheaval, but we need to look at more data to narrow down precisely when the changes occurred,” declares Wong

Source: ESO

Posted on by Nancy Atkinson

Planetary Scientists Studying Changes in Red Spot Junior

As far as storms go, nothing will rival Jupiter’s Great Red Spot (GRS). But of interest is a smaller and newer storm called Oval BA, a giant anticyclone on Jupiter also known as Red Spot Junior. ‘Smaller’ is a relative term, as although Oval BA is about half the size of GRS, it has a diameter about the size of our Earth. It formed in 2000 as several vortices converged. However, recently Oval BA has undergone some changes. Suddenly it turned from white to red in a period of just a few months, and planetary scientists are trying to understand the processes that could cause the changes. While they are able to explain some of Red Spot Junior’s attributes, they are puzzled by others.

“Our group has made an in-depth analysis of all the aspects regarding the history and evolution of Oval BA,” said Dr. Santiago Pérez-Hoyos, of the Planetary Science Group of the University of the Basque Country in Spain. “The most strongly reddened region was an annulus around its centre. However, when we calibrated images taken with the Hubble Space Telescope, we found that it didn’t actually alter in red or infrared wavelengths during the period. Instead, it became darker in blue and ultraviolet wavelengths, which made it appear visually redder.”

The apparent reddening was first reported by amateur astronomers in early 2006, but it was not until April that professional astronomers were able to image the impressive alteration of the second largest storm in the Solar System after the Great Red Spot (GRS).

Using data from Cassini, the Hubble Space Telescope, NASA’s New Horizons mission and computer models the Planetary Science Group analyzed possible causes for the color change, including alterations to dynamical, photochemical and diffusion processes.

Pérez-Hoyos said, “The most likely cause appears to be an upward and inward diffusion of either a colored compound or a coating vapor that may interact later with high energy solar photons at the upper levels of Oval BA.”

The group were able to rule out that the reddening was caused by any dynamical processes. They found no change to the strength of the “hurricane” and, although some changes in the circulation around the spot had taken place, the maximum wind speeds (which may range up to 400 kilometers per hour or more) were consistent with measurements previous to 2000 of the storms that combined to form Oval BA.

The group modeled the wind flow in detail using high resolution simulations, in order to understand why the red material may be confined to the annulus region and how the color change happened in the observed time scales. The model accounts well for the temperature and wind structure inside the oval BA.

Models also showed that the change could not be attributed to interactions of Oval BA with the GRS, which were relatively close at the time. The flow around both vortices is in the zonal directions and is so strong that separates both storms

The oval height did not change over the period and there were no large changes in the temperature gradient of the oval.

Pérez-Hoyos said, “There is much to be understood about this problem yet. Future spacecraft missions and a continuous observation of the planet (as done by amateur astronomers) will surely give us new clues on the behaviour of Jupiter’s atmosphere that will result in a better understanding of it.”
The team presented their findings at the European Planetary Science Congress in Münster on Monday, 22nd September.

Source: European Planetary Conference

Posted on by Ian O'Neill

Could Jupiter and Saturn Contain Liquid Metal Helium?

Rendering of a blue liquid metal... could this be what metallic helium looks like? Source: http://tinyurl.com/6lffol (waxellis)

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The interiors of the two gas giants, Jupiter and Saturn, are pretty extreme places. With atmospheric pressures of around 70 million Earth atmospheres, the phases of material become a bit difficult to understand. Usually when we think of a liquid metal, we have thoughts about liquid mercury at room temperature (or the reassembling liquid metal T-1000 played by Robert Patrick in the film Terminator 2), rarely do we consider two of the most abundant elements in the Universe to be a liquid metal in certain conditions. And yet, this is what a team of physicists from UC Berkley are claiming; helium and hydrogen can mix together, forced by the massive pressures near the cores of Jupiter and Saturn, forming a liquid metal alloy, possibly changing our perception of what lies beneath those Jovian storms…

Usually planetary physicists and chemists focus most of their attention on the characteristics of the most abundant element in the Universe: hydrogen. Indeed, over 90% of both Jupiter and Saturn is hydrogen too. But within these gas giant’s atmospheres is not the simple hydrogen atom, it is the surprisingly complex diatomic hydrogen gas (i.e. molecular hydrogen, H2). So, to understand the dynamics and nature of the insides of the most massive planets in our Solar System, researchers from UC Berkley and London are looking into a far simpler element; the second most abundant gas in the Universe: helium.

Raymond Jeanloz, a professor at UC Berkeley, and his team have uncovered an interesting characteristic of helium at the extreme pressures that can be exerted near the cores of Jupiter and Saturn. Helium will form a metallic liquid alloy when mixed with hydrogen. This state of matter was thought to be rare, but these new findings suggest liquid metal helium alloys may be more common than we previously thought.

“This is a breakthrough in terms of our understanding of materials, and that’s important because in order to understand the long-term evolution of planets, we need to know more about their properties deep down. The finding is also interesting from the point of view of understanding why materials are the way they are, and what determines their stability and their physical and chemical properties.” – Raymond Jeanloz.

Jupiter for example exerts an enormous pressure on the gases in its atmosphere. Due to it’s large mass, one can expect pressures up to 70 million Earth atmospheres (no, that isn’t enough to kick-start fusion…), creating core temperatures of between 10,000 to 20,000 K (that’s 2-4 times hotter than the Sun’s photosphere!). So helium was chosen as the element to study under these extreme conditions, a gas that makes up 5-10% of the Universe’s observable matter.

Using quantum mechanics to calculate the behaviour of helium under different extreme pressures and temperatures, the researchers found that helium will turn into a liquid metal at very high pressure. Usually, helium is thought of as a colourless and transparent gas. In Earth-atmosphere conditions this is true. However, it turns into an entirely different creature at 70 million Earth atmospheres. Rather than being an insulating gas, it turns into a conducting liquid metal substance, more like mercury, “only less reflective,” Jeanloz added.

This result comes as a surprise as it has always been thought that massive pressures make it more difficult for elements like hydrogen and helium to become metal-like. This is because the high temperatures in locations like Jupiter’s core cause increased vibrations in atoms, thus deflecting the paths of electrons trying to flow in the material. If there is no electron flow, the material becomes an insulator and cannot be called a “metal.”

However, these new findings suggest that atomic vibrations under these kinds of pressures actually have the counter-intuitive effect of creating new paths for the electrons to flow. Suddenly the liquid helium becomes conductive, meaning it is a metal.

In another twist, it is thought that the helium liquid metal could easily mix with hydrogen. Planetary physics tells us that this isn’t possible, hydrogen and helium separate like oil and water inside the gas giant bodies. But Jeanloz’s team has found that the two elements could actually mix, creating a liquid metal alloy. If this is to be the case, some serious re-thinking of planetary evolution needs to be done.

Both Jupiter and Saturn release more energy than the Sun provides meaning both planets are generating their own energy. The accepted mechanism for this is condensing helium droplets that fall from the planets’ upper atmospheres and to the core, releasing gravitational potential as the helium falls as “rain.” However, if this research is proven to be the case, the gas giant interior is likely to be a lot more homogenous than previously thought meaning there can be no helium droplets.

So the next task for Jeanloz and his team is to find an alternate power source generating heat in the cores of Jupiter and Saturn (so don’t go re-writing the textbooks quite yet…)

Source: UC Berkeley

Posted on by Tammy Plotner

StarGazer’s Telescope: Jumpin’ Jupiter!

Greetings, Fellow Stratos Dwellers! Have you had more than your fair share of clouds lately and are hankering for a few photons? Skies haven’t been spectacular in this part of the world either and when it is clear, the heat is sure making it difficult to get a nice steady view. But, it’s a nice night out. Wanna’ take out the StarGazer’s telescope and have a look at Jupiter? I’ll see you in the back yard…

Yes. The skies are still hazy, but it’s a warm night. Isn’t it something to see Jupiter up there riding along on the Milky Way? Makes me think of that crazy song… “Now that’s she’s back in the atmosphere, with drops of Jupiter in her hair..” Ok! Ok! I know we have to keep it quiet or we’ll wake the neighbors. Careful walking around the edge of the pool while you’re looking up. I don’t want to have to fish you out! You’ll see the telescope set up right over there. Go ahead. The eyepiece is waiting on you.

What’s that? Oh, yeah. It is awesome! Did you know that it has two and a half times more mass than all of the other planets put together? In fact, if it had much more mass Jupiter would shrink. Don’t laugh! I’m not kidding. If Jupiter gained more weight it could have even conceivably been a star. Can you imagine that? Then we’d never have a dark night.

Hmmm? Yes. You’re right. There are very noticeable markings when it steadies down a bit. Those are the cloud zones. The white one in the center is the EZ. Now quit that laughing! It stands for equatorial zone. The dark one underneath the EZ is the north equatorial belt and the one on top of it is the south. Yes. There’s lots of other fine lines, too. Below the north equatorial belt is the tropical and temperate zones. Same goes for the south up above. Just a bunch of fast moving ammonia crystals with maybe a little ammonium hydrosulfide thrown in for good measure. As phosphorus, sulfur or maybe even hydrocarbons swirl up from below, the ultraviolet light from Sol gives ’em a little suntan.

Hey! You saw it? Good for you! Yep. Just a little right of center in the southern tropical zone. That’s why I called you out here tonight. The Great Red Spot isn’t all that red, is it? Just a strange, salmon colored oval that shows up every now and again when things steady off. Yes, it sure is a storm. An anticyclonic storm that we know started at least as early as 1831 and maybe even as early as 1665. Sometimes it rotates fast and sometimes it rotates slow, but it always rotates counterclockwise to Jupiter. No one really knows why it is the color it is, but we do know its cooler than the other cloudtops and big enough at times to swallow three planet Earths. Now, move over…

It’s my turn.

Posted on by Nancy Atkinson

“Baby Red Spot” May Have Met Demise on Jupiter

The Great Red Spot on Jupiter has been observed for over 150 years, and it doesn’t appear this anti-cyclonic storm is showing any signs of letting up. How does it maintain its power? Well, like a planetary Pac-Man, it “eats up” other storms, zapping them of their power. The sequence of images here from the Hubble Space Telescope shows three different storms on Jupiter: The Great Red Spot, Red Spot Jr. (otherwise known as Oval BA, to the south of GRS), and Baby Red Spot, to the left of GRS in the first two images. Baby got a little too close to big brother GRS, and may have been snuffed out. But GRS keeps on keeping on. These three natural-color Jupiter images were made from data acquired on May 15, June 28, and July 8, 2008, by the Hubble’s Wide Field Planetary Camera 2.

Red Spot Jr. first appeared on Jupiter in early 2006 when a previously white storm turned red. This is the second time, since turning red, it has skirted past its big brother apparently unscathed. More on Jr. or Oval BA over at the BA himself, Phil Plait’s Bad Astronomy.

But poor little Baby Red Spot, which is in the same latitudinal band as the GRS. This new red spot first appeared earlier this year. The baby spot gets ever closer to the GRS in this picture sequence until it is caught up in GRS’s anticyclonic spin. In the final image the baby spot is deformed and pale in color and has been spun to the right (east) of the GRS. The prediction is that the baby spot will now get pulled back into the GRS “Cuisinart” and disappear for good. This is one possible mechanism that has powered and sustained the GRS for at least 150 years.

Each image covers 58 degrees of Jovian latitude and 70 degrees of longitude (centered on 5 degrees South latitude and 110, 121, and 121.

Original News Source: HubbleSite

Posted on by Matt Williams

What are Temperatures Like on Jupiter?

A true-color image of Jupiter taken by the Cassini spacecraft. The Galilean moon Europa casts a shadow on the planet's cloud tops. Credit: NASA/JPL/University of Arizona

Jupiter, which takes its name from the father of the gods in ancient Roman mythology, is the largest planet in our Solar System. It also has the most moon’s of any solar planet – with 50 accounted for and another 17 awaiting confirmation. It has the most intense surface activity, with storms up to 600 km/h occurring in certain areas, and a persistent anticyclonic storm that is even larger than planet Earth.

And when it comes to temperature, Jupiter maintains this reputation for extremity, ranging from extreme cold to extreme hot. But since the planet has no surface to speak of, being a gas giant, it’s temperature cannot be accurately measured in one place – and varies greatly between its upper atmosphere and core.

Currently, scientists do not have exact numbers for the what temperatures are like within the planet, and measuring closer to the interior is difficult, given the extreme pressure of the planet’s atmosphere. However, scientists have obtained readings on what the temperature is at the upper edge of the cloud cover: approximately -145 degrees C.

Because of this extremely cold temperature, the atmosphere at this level is composed primarily of ammonia crystals and possibly ammonium hydrosulfide – another crystallized solid that can only exist where conditions are cold enough.

However, if one were to descend a little deeper into the atmosphere, the pressure would increases to a point where it is ten times what it is here on Earth. At this altitude, the temperature is thought to increase to a comfortable 21 °C, the equivalent to what we call “room temperature” here on Earth.

Descend further and the hydrogen in the atmosphere becomes hot enough to turn into a liquid and the temperature is thought to be over 9,700 C. Meanwhile, at the core of the planet, which is believed to be composed of rock and even metallic hydrogen, the temperature may reach as high as 35,700°C – hotter than even the surface of the Sun.

Interestingly enough, it may be this very temperature differential that leads to the intense storms that have been observed on Jupiter. Here on Earth, storms are generated by cool air mixing with warm air. Scientists believe the same holds true on Jupiter.

A close-up of Jupiter's great red spot. Credit: NASA/JPL-Caltech/ Space Science Institute
A close-up of Jupiter’s great red spot, an anticyclonic storm that is larger than Earth. Credit: NASA/JPL-Caltech/ Space Science Institute

One difference is that the jet streams that drive storms and winds on Earth are caused by the Sun heating the atmosphere. On Jupiter it seems that the jet streams are driven by the planets’ own heat, which are the result of its intense atmospheric pressure and gravity.

During its orbit around the planet, the Galileo spacecraft observed winds in excess of 600 kph using a probe it deployed into the upper atmosphere. However, even at a distance, Jupiter’s massive storms can be seen to be humungous in nature, with some having been observed to grow to more than 2000 km in diameter in a single day.

And by far, the greatest of Jupiter’s storms is known as the Great Red Spot, a persistent anticyclonic storm that has been raging for hundreds of years. At 24–40,000 km in diameter and 12–14,000 km in height, it is the largest storm in our Solar System. In fact, it is so big that Earth could fit inside it four to seven times over.

Given its size, internal heat, pressure, and the prevalence of hydrogen in its composition, there are some who wonder if Jupiter could collapse under its own mass and trigger a fusion reaction, becoming a second star in our Solar System. There are a few reasons why this has not happened, much to the chagrin of science fiction fans everywhere!

This cut-away illustrates a model of the interior of Jupiter, with a rocky core overlaid by a deep layer of liquid metallic hydrogen. Credit: Kelvinsong/Wikimedia Commons
This cut-away illustrates a model of the interior of Jupiter, with a rocky core overlaid by a deep layer of liquid metallic hydrogen. Credit: Kelvinsong/Wikimedia Commons

For starters, despite its mass, gravity and the intense heat it is believed to generate near its core, Jupiter is not nearly massive or hot enough to trigger a nuclear reaction. In terms of the former, Jupiter would have to multiply its current mass by a factor of 80 in order to become massive enough to ignite a fusion reaction.

With that amount of mass, Jupiter would experience what is known as gravitational compression (i.e. it would collapse in on itself) and become hot enough to fuse hydrogen into helium. That is not going to happen any time soon since, outside of the Sun, there isn’t even that much available mass in our Solar System.

Of course, others have expressed concern about the planet being “ignited” by a meteorite or a probe crashing into it – as the Galileo probe was back in 2003. Here too, the right conditions simply don’t exist (mercifully) for Jupiter to become a massive fireball.

While hydrogen is combustible, Jupiter’s atmosphere could not be set aflame without sufficient oxygen for it to burn in. Since no oxygen exists in the atmosphere, there is no chance of igniting the hydrogen, accidentally or otherwise, and turning the planet into a tiny star.

Scientists are striving to better understand the temperature of Jupiter in hopes that they will eventually be able to understand the planet itself. The Galileo probe helped and data from New Horizons went even further. NASA and other space agencies are planning future missions that should bring new data to light.

To learn more about Jupiter, check out this article on how weather storms on Jupiter form quickly. Here’s Hubblesite’s News Releases about Jupiter, and NASA’s Solar System Explorer.

We’ve also recorded an entire show just on Jupiter for Astronomy Cast. Listen to it here, Episode 56: Jupiter, and Episode 57: Jupiter’s Moons.

Sources:
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Jupiter&Display=OverviewLong
http://www.jpl.nasa.gov/news/news.cfm?release=2008-013

Posted on by Nancy Atkinson

Hubble Spies Third Red Spot on Jupiter

Jupiter appears to be breaking out with spots, as a third red storm has joined the Great Red Spot and Red Spot Jr. (or Oval BA) in the planet’s turbulent atmosphere. This third spot used to be a white storm, and its change to a red color might mean the storm is becoming more powerful. Astronomers believe these new images captured by both the Hubble and the Keck telescope may show that Jupiter is undergoing a major climate change, as was predicted four years ago.

“One of the most notable changes we observe in both the Hubble and Keck images is the change from a rather bland, quiescent band surrounding the Great Red Spot just over a year ago to one that is incredibly turbulent at both sides of the spot,” said Imke de Pater from the University of California Berkley. “During all previous HST observations and spacecraft encounters, starting with Voyager in 1979, such turbulence was seen only on the west or left side of the spot.”

The Great Red Spot has been around as long as 200 to 350 years, based on early telescopic observations. If the new red spot and the Great Red Spot continue on their courses, they will encounter each other in August. Astronomers will keep a close watch on whether the small oval will either be absorbed or repelled from the Great Red Spot. Red Spot Jr. which lies between the two other spots, and is at a lower latitude, will pass the Great Red Spot in June.

The Great Red Spot is a persistent, high-pressure storm whose cloud head sticks some 8 kilometers (5 miles) above the surrounding cloud deck. The new spot is much smaller than the other two and lies to the west of the Great Red Spot in the same latitude band of clouds.

The visible-light images were taken by Hubble’s Wide Field Planetary Camera 2 on May 9 and 10, and near-infrared adaptive optics images were taken by the W.M. Keck telescope on May 11.

These images may support the idea that Jupiter is in the midst of global climate change, as first proposed in 2004 by Phil Marcus, a professor of mechanical engineering at the University of California, Berkeley. The planet’s temperatures may be changing by 15 to 20 degrees Fahrenheit. The giant planet is getting warmer near the equator and cooler near the South Pole. He predicted that large changes would start in the southern hemisphere around 2006, causing the jet streams to become unstable and spawn new vortices.

“The appearance of the planet’s cloud system from just north of the equator down to 34 degrees south latitude keeps surprising us with changes and, in particular, with new cloud features tha haven’t been previously observed,” said Marcus. “Whether or not Jupiter’s climate has changed due to a predicted warming, the cloud activity over the last two and a half years shows dramatically that something unusual has happened.”

Original News Source: Hubble Press Release

Posted on by Ian O'Neill

Could Jupiter Wreck the Solar System?

Could Jupiter throw the planets into eachother? (NASA)

Scientists have expressed their concern that the Solar System may not be as stable as it seems. Happily orbiting the Sun, the eight planets (plus Pluto and other minor planets) appear to have a high degree of long-term gravitational stability. But Jupiter has a huge gravitational influence over its siblings, especially the smaller planets. It appears that the long-term prospects for the smallest planet are bleak. The huge gravitational pull of Jupiter seems to be bullying Mercury into an increasingly eccentric death-orbit, possibly flinging the cosmic lightweight into the path of Venus. To make things worse, there might be dire consequences for Earth…

Jupiter appears to be causing some planetary trouble. This gas giant orbits the Sun at a distance of approximately 5 AU (748 million km), that’s five times further away from the Sun than the Earth. Although the distance may be huge, this 318 Earth-mass planet’s gravitational pull is very important to the inner solar system planets, including tiny Mercury. Mercury orbits the Sun in an elliptical orbit, ranging between 0.47 AU (at aphelion) to 0.31 AU (at perihelion) and is only 0.055 Earth masses (that’s barely five-times the mass of our Moon).

Running long-term simulations on the orbits of our Solar System bodies, scientists in France and California have discovered something quite unsettling. Jacques Laskar of the Paris Observatory, as well as Konstantin Batygin and Gregory Laughlin of the University of California, Santa Cruz have found that Jupiter’s gravity may perturb Mercury’s eccentric orbit even more. So much so their simulation predicts that Mercury’s orbit may extend into the path of Venus; or it might simply fall into the Sun. The researchers formulate four possible scenarios as to what may happen as Mercury gets disturbed:

  1. Mercury will crash into the Sun
  2. Mercury will be ejected from the solar system altogether
  3. Mercury will crash into Venus
  4. Mercury will crash into Earth

The last option is obviously the worst case scenario for us, but all will be bad news for Mercury, the small planet’s fate appears to be sealed. So what’s the likelihood Mercury could crash into the Earth? If it did, the asteroid that most likely wiped out the dinosaurs will seem like a drop in the ocean compared with a planet 4880 km in diameter slamming into us. There will be very little left after this wrecking ball impact.

But here’s the kicker: There is only a 1% chance that these gravitational instabilities of the inner Solar System are likely to cause any kind of chaos before the Sun turns into a Red Giant and swallows Mercury, Venus, Earth and Mars in 7 billion years time. So, no need to look out for death-wish Mercury quite yet… there’s a very low chance that any of this will happen. But some good news for Mars; the researchers have also found that if the chaos does ensue, the Red Planet may be flung out of the Solar System, possibly escaping our expanding Sun. So, let’s get those Mars colonies started! Well, within the next few billions of years anyhow…

These results by Batygin and Laughlin will be published in The Astrophysical Journal.

Source: Daily Galaxy

Here are some facts on Mercury.

Posted on by Nancy Atkinson

Jupiter’s Rings Are ‘Made in the Shade’

Jupiter's rings. Image Credit: University of Maryland

Robotic spacecraft can gather a lot of data, and sometimes it takes years to sort through all the information acquired. Case in point: The Galileo spacecraft orbited Jupiter from 1995-2003. One discovery made by this mission was an anomaly in Jupiter’s rings. For the most part, the rings fall into the standard model of ring formation where the ring particles are shepherded by the orbits of four of Jupiter’s moons; Adrastea, Metis, Amalthea and Thebe (closest to farthest.) But a faint outward protrusion of dust extends beyond the orbit of Thebe, and scientists were mystified why this was occurring.

But a new study of data from the Galileo mission has found that this extension results from the interplay of shadow and sunlight on dust particles that make up the rings.

“It turns out that the outer ring’s extended boundary and other oddities in Jupiter’s rings really are ‘made in the shade,'” said Douglas Hamilton, a professor of astronomy at the University of Maryland. “As they orbit about the planet, dust grains in the rings alternately discharge and charge when they pass through the planet’s shadow. These systematic variations in dust particle electric charges interact with the planet’s powerful magnetic field. As a result small dust particles are pushed beyond the expected ring outer boundary, and very small grains even change their inclination, or orbital orientation, to the planet.”

The Galileo spacecraft was deliberately maneuvered to plunge into Jupiter in 2003 in an effort to protect one of its own discoveries – a possible ocean beneath the icy crust of the moon Europa (scientists didn’t want the spacecraft to one day impact and possibly contaminate Europa.) During this maneuver, the spacecraft dove through the rings and registered thousands of impacts from dust particles with its supersensitive dust detector.

Hamilton and German co-author Harald Krüger studied the impact data on dust grain sizes, speeds, and orbital orientations. Krüger analyzed the new data set and Hamilton created elaborate computer models that matched dust and imaging data on Jupiter’s rings and explained the observed unexpected behavior.

Take a look at Hamilton’s incredible models here.

“Within our model we can explain all essential structures of the dust ring we observed, ” said Krüger.

According to Hamilton, the mechanisms they identified affect the rings of any planet in any solar system, but the effects may not be as evident as it is at Jupiter. “The icy particles in Saturn’s famous rings are too large and heavy to be significantly shaped by this process, which is why similar anomalies are not seen there, ” he said. “Our findings on the effects of shadow may also shed some light on aspects of planetary formation because electrically charged dust particles must somehow combine into larger bodies from which planets and moons are ultimately formed.”

Original News Source: University of Maryland press release