Month: December 2018

Jupiter’s moons emit extremely powerful waves

Jupiter’s moons Europa and Ganymede have extremely powerful chorus waves that are much stronger than any other ones found in our solar system.

A team of international astronomers have found that the chorus waves around Jupiter’s moons Ganymede and Europa are much more powerful than the waves around other planets in our solar system, a new study published in Nature Communications reports.

Chorus waves are electromagnetic waves that emit out from planets and cause different phenomena in their atmosphere. For instance, Earth’s waves cause the Northern Lights and generate extremely high-energy electrons.

In the new study, scientists analyzed such waves around the planets in our solar system and then used data gathered by the Galileo space to match that against Jupiter’s moons. That revealed the waves of Europa are 100 times more intense than average planetary waves, and the ones around Ganymede are 1 million times stronger than that.

“It’s a really surprising and puzzling observation showing that a moon with a magnetic field can create such a tremendous intensification in the power of waves,” said lead author Yuri Shprits, a professor at GFZ/ University of Potsdam, according to Phys.org.

While scientists are not sure why the natural satellites have such strong waves, they believe it could be partly due to the fact that they orbit within Jupiter’s magnetic field. That region is the largest field in the solar system, and it measures 20,000 times stronger than Earth’s.

At that power range, Ganymede would be able to accelerate particles to extremely high speeds and energies.

That is important because, as Earth’s chorus waves can create so-called “killer” electrons that severely damage spacecraft, there is a chance that Jupiter’s moons can generate them as well.

More research is needed, but such insight will give scientists a chance to understand the core processes that drive acceleration and loss around planets in our solar system. That may then allow them to gain new information about exoplanets as well as potential energy sources down the line.

“It’s a really surprising and puzzling observation showing that a moon with a magnetic field can create such a tremendous intensification in the power of waves,” added Shprits, in a statement.

“Twin” exoplanets formed through very different processes

Identical appearance can hide very different origins.

Two giant exoplanets in separate star systems are practically identical but likely formed through very different processes, according to a team of scientists led by Trent Dupuy of the Gemini Observatory.

Beta Pictoris b and and 2MASS 0249 c, found via direct imaging in 2009 and 2017 respectively, have the same masses–approximately 13 Jupiter masses–as well as the same brightnesses and spectra.

Although the two planets are alike enough for astronomers to refer to the newly-discovered planet as a “doppelganger” of the first, and the two have parent stars that likely formed in the same stellar nursery of gas and dust, scientists believe their origins are very different.

“We have found a gas giant that is a virtual twin of a previously known planet, but it looks like the two objects formed in different ways,” Dupuy said.

Many stars are born in stellar nurseries but subsequently wander away from one another. By observing both planets with the Canada-France-Hawaii Telescope (CFHT), the researchers determined they originated in the same stellar nursery.

However, the stars they orbit as well as their orbital distances are very different from one another. Beta Pictoris b is in a close orbit at approximately nine astronomical units (AU, with one AU equal to the average Earth-Sun distance or 93 million miles) around a star 10 times brighter than the Sun while 2MASS 0249 c circles a pair of brown dwarfs at a distance of 2,000 AU.

Brown dwarfs are the lowest end of the stellar category. Dim and cool, they are not hot enough to fuse hydrogen in their cores although some fuse deuterium, an isotope of hydrogen.

Gas giant planets typically begin their lives as small rocky cores that grow by gathering gas from their parent stars’ protoplanetary disks. Beta Pictoris b likely formed in this manner.

However, this formation process would not have been possible for 2MASS 0249 c because its two brown dwarf parents would not have had a large enough protoplanetary disk to provide the levels of gas needed to form a gas giant. This means the planet absorbed its gas directly from the stellar nursery.

“2MASS 0249 c and Beta Pictoris b show us that nature has more than one way to make very similar looking exoplanets. Beta Pictoris b probably formed like we think most gas giants do, starting from tiny dust grains. In contrast, 2MASS 0249 c looks like an underweight brown dwarf that formed from the collapse of a gas cloud. They’re both considered exoplanets, but 2MASS 0249 c illustrates that such a simple classification can obscure a complicated reality,” explained Kaitlin Kratter of the University of Arizona, who took part in the study.

A paper on the findings has been accepted for publication in the Astronomical Journal.

Astronomers discover 12 new moons orbiting Jupiter

The discovery provides insight into why the Jupiter system looks the way it does.

Astronomers have uncovered ten more moons orbiting around Jupiter, bringing the planet’s total satellite count to 79, reports Loren Grush for The Verge. Astronomers at Carnegie Institution for Science found these moons in March 2017 using the Blanco 4-meter telescope in Chile. Since the discovery, the moons have been observed multiple times and their exact orbits have been submitted for approval from the International Astronomical Union.

The moons are fairly small and break down into three different types. Two orbit closer to Jupiter, moving in the same direction the planet spins. Nine are about 15.5 million miles from the planet and revolve in the opposite direction, moving against Jupiter’s rotation. In this region, one of the moon’s that astronomer’s call Valetudo is moving with Jupiter’s spin, going in the opposite direction of all the other moons in the same area. “It’s basically driving down the highway in the wrong direction,” Scott Sheppard, an astronomer at Carnegie who led the discovery team, told The Verge. “That’s a very unstable situation. Head-on collisions are likely to happen in that situation.”

With this discovery, scientists believe it’s evidence that moon-on-moon collisions have happened in Jupiter’s past. Astronomers argue that the nine moons moving in the same direction far out from Jupiter, may actually be pieces of a bigger moon that existed long ago. Sheppard agrees, explaining “[w]e think, originally, there were three parent bodies, and, somehow, each of those parent bodies got broken apart. And a big question is: what broke those objects apart?” Valetudo provides a plausible explanation: with it going in opposition to other moons in the area, numerous head-on collisions likely occurred, reducing these celestial bodies to the small sizes observed today.

X-ray observatory images star eating its planet

Periodic dimming of young star likely caused by debris produced by planets’ destruction.

NASA’s Chandra X-ray Observatory may have caught the first ever image of a star devouring one or more of its orbiting planets.

Located approximately 450 light years from Earth, the young variable star RW Aur A has baffled scientists since 1937 by dimming, then brightening, every few decades. Recently, the dimming has occurred more frequently and lasted for longer durations.

In 2011, the star dimmed for several months, then brightened.  Three years later, in 2014, it dimmed again.  Two years later, it  brightened again until dimming once more in early 2017.

To determine what might be causing the dimming, a team of scientists observed the star with the Chandra telescope when it brightened in 2013 and when it dimmed in 2015 and 2017. They found the dimming corresponded with a decrease in X-ray emission.

X-rays come from a star’s outer atmosphere. By studying changes in the X-ray spectrum emitted by a star, scientists can determine the density and composition of material surrounding the star.

Based on these observations, the researchers determined that RW Aur A, which is very young star and part of a binary system with its companion RW Aur B is devouring planetesimals and possibly even young planets orbiting within its protoplanetary disk of dust and gas.

Interestingly, the two companion stars both have approximately the same mass as the Sun.

Planets and planetesimals that fall into their stars generate debris in the form of heavy layers of gas and dust, which can obscure their stars’ light.

“Computer simulations have long predicted that planets can fall into a young star, but we have never before observed that. If our interpretation of the data is correct, this would be the first time that we directly observe a young star devouring a planet or planets,” said study leader Hans Moritz Guenther of MIT‘s Kavli Institute for Astrophysics and Space Research.

The binary star system is located in the Taurus-Auriga Dark Clouds, a region of abundant stellar nurseries. Estimated to be approximately several million years old, the star, like other very young stars, is still surrounded by a protoplanetary disk of gas and dust.

Material in these disks can range from tiny dust grains all the way through full-fledged planets.

Chandra observations of RW Aur A in 2017 indicated the star was emitting a high level of iron atoms and that the disk surrounding it contained 10 times more iron than it did in 2013.

According to the researchers, the increase in iron was likely produced by a collision of two plantestimals or planets, one or both of which released iron into the disk.

“Much effort currently goes into learning about exoplanets and how they form, so it is obviously very important to see how young planets could be destroyed in interactions with their host stars and other young planets, and what factors determine if they survive,” Guenther stated.

A paper on the study has been published in the Astronomical Journal.

Io may have another volcano

Astronomers believe a hotspot discovered on Jupiter’s moon Io may be the site of another volcano.

The NASA Juno spacecraft has potentially discovered a hidden volcano in Jupiter’s moon Io.

Juno is an important instrument that has made significant contributions to astronomy. It has spent nearly 150 million miles in Jupiter’s orbit since it first went up in 2016. Since then, the craft has taken pictures, recorded time-lapse photos, and made new discoveries.

The volcano on Io is the newest addition to that list.

Researchers working with NASA first took note of the potential formation when analyzing data collected by the Jovian Infrared Auroral Mapper (JIRAM) instrument. Study of the Io revealed a brand new heat source near its south pole.

Though astronomers are not sure what the heat source is, chances are that it is another volcano. Io — which is known as the most volcanically active body in the solar system — already has plenty, and the finding would further reinforce that title.

The newly discovered hotspot sits 200 miles from the nearest known heat signature. While there is a chance it is a previously known volcano that moved over time, more research needs to be done before any conclusions can be made.

“The new Io hotspot JIRAM picked up is about 200 miles (300 kilometers) from the nearest previously mapped hotspot,” said Alessandro Mura, a Juno co-investigator from the National Institute for Astrophysics in Rome, according to Phys.org. “We are not ruling out movement or modification of a previously discovered hot spot, but it is difficult to imagine one could travel such a distance and still be considered the same feature.”

NASA plans to follow up on their research in the coming months to see what else they can figure out about Io. They hope the Juno craft will give them more insight after the next flyby, which is set to take place in a few days.

“We are not ruling out movement or modification of a previously discovered hotspot, but it is difficult to imagine one could travel such a distance and still be considered the same feature,” added Mura, in a statement.

Scientists discover 12 new moons of Jupiter

Finding brings the giant planet’s total number of moons to 79.

A group of scientists searching for a theorized planet in the outer solar system instead discovered 12 new moons of Jupiter, bringing the giant planet’s total count of moons to 79. All are small, with diameters ranging from 0.6 miles (one km) to 1.87 miles (three km).

Led by Scott S. Sheppard of the Carnegie Institute for Science, the research team found the moons in the spring of 2017 while using the Blanco 4-meter Telescope at Cerro Tololo Observatory in Chile and the American National Optical Astronomical Observatory. Because several separate observations are required to confirm an individual object is actually in orbit around Jupiter, confirmation of all 12 took a year to complete.

“Jupiter just happened to be in the sky near the search fields where we were looking for extremely distant solar system objects, so we were serendipitously able to look for new moons around Jupiter while at the same time looking for planets at the fringes of our solar system,” Sheppard explained.

Nine of the newly-discovered moons are part of a larger swarm in distant, retrograde orbits around the giant planet, which take about two years to orbit Jupiter. Having retrograde orbits mean they circle Jupiter in the opposite direction of the planet’s rotation.

Within this distant swarm, moons are divided into three separate orbital groups, each of which is theorized by scientists to be the result of an impact with a larger parent body, likely a comet, asteroid, or additional Jovian moon.

Two of the newly-found moons have prograde or direct orbits and are located much closer to Jupiter, in an inner swarm of satellites. These moons orbit Jupiter in less than one year. All moons in this swarm, based on their orbital inclinations and distances from Jupiter, are believed to be remnants of a larger single moon that broke apart in an impact.

Of all the newly discovered objects, one has a more inclined orbit than those in the inner swarm and takes approximately a year-and-a-half to orbit Jupiter. While its orbit is prograde, its inclination leads it to cross into the region of the retrograde, outer swarm of moons.

This “oddball” is the smallest of all Jovian moons, with a diameter of less than 0.6 miles (one km). Because its unusual but prograde orbit takes it into the region of the outer moons that have retrograde orbits, the chances of collisions occurring between the objects moving in opposite directions are high.

“This is an unstable situation. Head-on collisions would quickly break apart and grind the objects down to dust,” Sheppard said.

The researchers believe that this “oddball” moon may also be a remnant of a much larger moon, possibly one that caused the outer swarm to take retrograde orbits.

Scientists think these newly-found moons formed after the solar system’s main period of planet formation. Had they formed earlier, gas and dust left over from the solar nebula, as well as larger moons, would have destroyed them by driving them into the giant planet.

Ten new moons found around Jupiter

New technology has enabled researchers to detect 10 new moons in Jupiter’s orbit.

A team of astronomers from the Carnegie Institution for Science have discovered 10 previously unknown moons around Jupiter, bringing the planet’s total amount up to 79.

Researchers first found the new bodies while searching for distant objects at the edge of our solar system. During their study they noticed a handful of never-before-seen objects near Jupiter. Intrigued, they then tracked the bodies for a year and confirmed them as moons.

Two of the natural satellites orbit close to Jupiter. They are “prograde moons,” which means they orbit in the same direction as the planet spins. As a result, astronomers believe they are pieces of a larger moon that broke apart many years ago.

Seven of the new moons orbit further away and in the opposite direction, which means they are retrograde moons. The team believes those were also once apart of a much larger body.

The tenth moon is strange in that it orbits on the same path as the retrograde moons but orbits in the opposite direction. That suggests it is the remnant of a random object that Jupiter sucked in with its gravity, such as a rogue comet.

“This just shows how chaotic our Solar System was in the past,” said team leader Scott Sheppard, a researcher at the Carnegie Institute for Science, according to Gizmodo. These outer moons of Jupiter are remnants of chaos.”

Scientists just recently discovered the moons because telescope technology has come a long way within the last decade or two. That has enabled researchers to take much clearer pictures of the cosmos.

In fact, as technology continues to improve there is a chance even more moons could be found around Jupiter. That may one day help scientists understand the planet’s history and perhaps gain insight into the way other gas giants first formed.

“By looking at these outer moons we can get an insight into what the objects were like that ended up forming the planets we see today,” said Sheppard, according to The Washington Post. 

The universe appears to expand at different rates, study reports

New measurements show that modern physics cannot succinctly understand the rate at which the universe expands.

Astronomers from John Hopkins University have found new evidence that furthers the idea that the universe expands at different speeds depending on what part is observed, according to new research in The Astrophysical Journal. 

Many recent studies on the topic have found numerous discrepancies in how fast the universe moves out to distant locations.

In fact, the “tension” could reveal that scientists need to revise the modern understanding of how physics structures the universe and change ideas surround dark matter and dark energy.

Measurements gathered from the Hubble and Gaia space telescopes revealed that the universe expands at a rate of 45.6 miles per second per megaparsec. In other words, every 3.3 million light-years a galaxy is away from Earth, it appears to move 45 miles faster.

However, previous research from the Planck telescope shows that the more distant background universe moves at a slower 41.6 miles per second per megaparsec.

The difference between both of those measurements continues to grow as researchers refine measurements over time. In fact, the data from the new study reveals a gap that is four times the size of their combined uncertainty — a value that reflects researchers’ level of confidence in the results of a trial.

“At this point, clearly it’s not simply some gross error in any one measurement,” said lead author Adam Riess, an astronomy and physics professor at Johns Hopkins University, in a statement. “It’s as though you predicted how tall a child would become from a growth chart, and then found the adult he or she became greatly exceeded the prediction. We are very perplexed.”

Nobody can explain why the universe accelerates as it expands. Some believe it may be the result of dark matter or dark energy, while others suggest that it may be the result of a yet undiscovered particle.

While researchers are still analyzing the measurements from the recent study, they will likely help scientists better predict how the early universe have evolved into the expansion rate noted today.

“The tension seems to have grown into a full-blown incompatibility between our views of the early and late time universe,” added Riess, according The Independent. “At this point, clearly it’s not simply some gross error in any one measurement.

Telescope gives glimpse of Milky Way’s center

The MeerKAT telescope provides astronomers with a brand new glimpse of the center of the Milky Way.

A brand new mega-telescope has taken the best picture of the Milky Way’s center on record.

The new technology — known as MeerKAT radio telescope — is made up of 64 small dishes that work to detect radio waves. All of the devices sit in the Karoo region of South Africa and are much more sensitive than any other similar object.

That extra sensitivity is key because it allowed MeerKAT to image the region around the supermassive black hole at the center of our galaxy — which sits 25,000 light-years away — in great detail.

The colors in the image reveal the brightness of the radio waves detected, and they range from red to orange to white.

While the picture seems like nothing more than a giant fireball at first glance, it reveals may new features.

For example, it shows compact sources of the long, magnetized filaments that come off the Milky Way’s central region, and it also provides a new look into previously unknown supernova remnants and star-forming regions.

The filaments are particularly important because, while researchers have spent decades analyzing them, nobody understands why they are only near the black hole.

“This image is remarkable,”said Farhad Yusef-Zadeh, a researcher at Northwestern University, according to Newsweek. “It shows so many features never before seen, including compact sources associated with some of the filaments, that it could provide the key to cracking the code and solve this three-decade riddle.”

Another reason the image is so special is because the center of the Milky Way is notoriously hard to photograph. Not only is it incredibly far away, but it also sits behind the constellation Sagittarius, which hides it from optical telescopes.

MeerKAT gets around that because it is able to detect certain radio wavelengths that other machines cannot.

“We wanted to show the science capabilities of this new instrument,” said Fernando Camilo, chief scientist of the South African Radio Astronomy Observatory (SARAO), which built and operates MeerKAT, according to Science Alert. “The center of the galaxy was an obvious target: unique, visually striking and full of unexplained phenomena – but also notoriously hard to image using radio telescopes … Although it’s early days with MeerKAT, and a lot remains to be optimised, we decided to go for it – and were stunned by the results.”

Astronomers observe unique binary asteroid

A binary asteroid known as 2017 YE5 is unlike any other such object on record.

Scientists at Arecibo Observatory in Puerto Rico and the Green Bank Observatory in West Virginia have discovered a pair of similarly-sized asteroids locked in their binary orbit around a mutual center of gravity.

The team first detected the odd object, known as 2017 YE5, in December of last year. At the time, it sat an such an angle that scientists could not determine if it was two distinct objects or two lobes of the same object joined at one point, Science Alert reports.

However, last month the pair came closer to Earth than they had ever been, which then allowed astronomers to get a much better look. They did that by shooting a radar signal out towards the asteroid. The beam then bounced off the object and shot back down towards our planet. Individual observations were made as well.

That revealed the asteroids make one full orbit around each other once every 20 to 24 hours.

Though observations estimate that about 15 percent of all near-Earth asteroids that measure more than larger than 650 feet across are binaries, most of them are made up of one large asteroid and one small one.

YE5 is unique because both objects measure 3,000 feet across, showing that they are roughly the same size. In addition, the rocks each reflected the radar signal differently. That shows they likely have different surface roughness or density.

More research needs to be done on the pair before such questions can be answered, and the team plans to do that the next time the asteroids fly past Earth in roughly four-and-a-half years.

In the meantime, researchers will analyze data taken from recent observations and attempt to discover more about the densities of the object. That could then provide new insight into its structure and composition.