One More Shot

Summary: The Cassini spacecraft is on the last phase of its mission. It has begun a series of extremely elliptical orbits around Saturn before it will ultimately plunge into the planet and self-destruct. But while it is still working, there is data to collect. Already we have seen new images of the hexagonal clouds at the North pole of the planet and we are getting new images of the rings. But there is one object in particular that some astronomers have their sights set on.

First noticed in 2013 as a long, bright smudge along Saturn's A-ring, the mysterious object, known as Peggy, is one of the new image goals of the mission. There is no clear image of this smudge yet, and it would be a long time before another mission had a chance to photograph this mystery. The team only has until September to get the image, but thankfully Cassini will be flying close to this A-ring and the mysterious object has now been made into one of the last objectives for the mission.

Saturn can sometimes be used as a model for exoplanet formation in other star systems. The rings act similarly to how we believe dust gathers around a star until planets are formed. It is hoped that by studying Peggy more closely, we will gain more insight into the earliest stages of planet formation. Specifically it is hoped to be a model for how planets migrate. In the few years since Professor Carl Murray discovered this object, astronomers have been able to track it's motion and observe as it has drifted closer and further away from Saturn by a few kilometers.

Even more interesting, as scientists looked back through archival data with recent data from Cassini, they discovered that Peggy might have recently broken into two objects. Recent data shows another, smaller object following directly behind Peggy and orbital dynamics seem to indicate that they would have met in early 2015. Now there is the possibility that a collision of some sort caused both the fracturing of Peggy and also the new orbital radius.

Along with hoping to take better resolved images of Peggy, Cassini scientists also hope to determine the mass of Saturn's rings. Dr. Linda Spiker, the project scientist, points out that the mass can provide key clues about the age of the rings. This in turn would help with models of how the moons were formed. With lots of exciting science coming from the ringed planet this year, this is shaping up to be a great year for astronomy.

BBC News

New Images from esa Mars mission

Summary: Although the Schiaparelli lander was not as successful as hoped and plummeted into the surface of Mars rather than gently landing, the satellite it was released from is still working and returning new images of the surface of the planet. This Trace Gas Orbiter (TGO) is orbiting the planet and using it's impressive cameras to send us back images with a resolution of 2.8 metres per pixel. The camera's principal investigator, Nicolas Thomas, compared it to "flying over Bern at 15,000km/h and simultaneously getting sharp pictures of cars in Zurich."

Other sensors on board will also be investigating the atmospheric gases and looking for water vapor, nitrogen dioxide, and sulphur dioxide among other chemical species. The goal is to detect possible signs of microbial life on the surface and detect the presence of hydrated minerals.

Source and images

Gaia and a new Age of Universe

Summary: The study of astronomy is an old one, but as headlines show, it is a constantly changing field. As our instruments change, we discover that the numbers we thought we knew need some readjustment. In this case, the Gaia space craft from the esa is forcing astronomers to look about the expansion rate of the universe. Again.

This is not the first time there have been some discrepancies in the estimate for the age of the universe. But Gaia is one of the most precise telescopes we have at the moment. Just recently it published precise coordinated for one billion stars. This is leaps ahead of the last survey of this type.

Gaia's estimate of the age of the universe is based upon Cepheid variable stars. These stars pulse with a very specific brightness and rate of pulsation. This makes it easier to tell how far away they are from us and to determine the age of the stars nearby. Gaia has precisely found 212 of these Cepheid stars and with these data, Professor Reiss's team calculates a Hubble constant of 73km/Mpc. This is about the same as they calculated with Hubble data. But it is not the same number found in most textbooks as the accepted value. And it is not due to outdated textbooks. It is because of the methods used to solve for the Hubble constant. The Planck mission gives a much lower value of 66.9km/Mpc.

Why is there such a discrepancy? We aren't entirely sure, but we can probably place a lot of the blame on dark matter. Hopefully as Gaia continues forward on it's mission, we will be able to narrow down the range of possible Hubble constants, and thus the age of the universe and no longer have a few hundred million year gap. Maybe we will even be able to place stricter bounds on what dark matter actually is and what effect it has on our universe.

Source

Also, the Ig Nobel prizes were awarded this week and they are, as always, amazing.

Juno update

Summary: After 5 years and 1.8 billion miles, the Juno spacecraft has made its first flyby of Jupiter. At only 2,500 miles above the cloud tops, this is the closest any spacecraft has come to the gas giant of our solar system.

One of the things that makes Juno exciting is the panoramic colour camera which allows for stunning images to be sent back in addition to data from its other instruments. 

Juno will make 35 further flybys in order to measure Jupiter's water content, magnetic fields, and to look for the possibility of a solid core. Will all of this new data, it is hoped that scientists will have a better idea of how the planets formed in the early solar system.

BBC News

Expanding Expansion

Summary: Based on new data from the Hubble Space Telescope, the universe might actually be expanding faster than previously thought. This new data comes from an updated study of the velocities of Cepheid Variable Stars and Type Ia Supernovae to determine a value for the Hubble constant. The new data points to a slightly higher value of 73.24 km/sec/Mpc. This is only slightly higher than the value of 70 used in many textbooks.

However, this only increases the gap between the value gained from this method and the value gained from the Planck telescope. Those experiments lead to a Hubble value of 66.53 km/sec/Mpc. This means the difference of a few hundred million years when calculating the age of the universe.

At this point, astronomers can only guess at the cause of the discrepancy. Many point fingers at Dark Energy or a fourth flavor of Neutrino, but ultimately we hope that the next generation of telescopes can show us the answers.

Source:
BBC News
arXiv

Double Black Hole Hails Discovery of Gravity Waves

Summary: It's the announcement of a discovery you didn't know you were waiting for. The detection of gravitational waves. It sounds weird, of course, but Einstein was onto something big when he was working on his theory of general relativity. Similar to a ball warping the surface of a rubber sheet, or a kayak being thrown into the water, large objects in outer space warp the fabric of the four dimensional spacetime that we live in.

When this happens, gravitational waves ripple through space and expand or contract the space around them. These waves have been undetectable until now. It is thanks to the LIGO interferometer that we can detect these faint waves in the universe. These waves are understandably hard to detect, the measurements are on a scale less than a width of an atom. They were able to detect this thanks to a double black hole.

Quite deservedly, the scientists involved are quite proud of their work. As this is both the first detection of gravity waves and the first direct detection of a black hole in addition to being confirmation of general relativity, they are confident that there is a Nobel Prize in their future and I am inclined to agree.

Either way, it is an exciting breakthrough in astronomy and one that I am excited to have as I enter the field.


APS Article
BBC News
Nature
SciShow

Strong Forces Between Antipotons

Summary: Woah, a story about antimatter on an antimatter blog! Finally.

Unlike a lot of other anitmatter and particle physics news, this does not come to us from CERN but rather from in Relativistic Heavy Ion Collider (RHIC) at Brookhaven in New York. Here physicists were able to measure the interactions between antiprotons. It seems like it is also the strong force, an attractive force, that holds the antiprotons together just as it also holds the protons together. This is just one more way in which protons and antiprotons are essentially the same, the exception of their opposite charge. Because of the similarity scientists can rule this out as a possible explanation for the matter/antimatter asymmetry in the universe today.

BBC News
Nature

Tractor Beams made of Sound

Summary: It may not be quite the tractor beam that you expect from a scifi show like "Star Trek," but we are getting closer. The way these scientists have developed relies on the pressure of sound waves. Instead of trying to create a concentrated beam that holds a particle, they instead create a vacuum of space, bounded by high intensity waves all around it. Then  by adjusting the boundaries, they are able to move the trapped particle. Currently the capabilities of the design only apply up to pea-sized particles at less than 40cm away.

Despite the apparent 3D nature of the holding pattern, it only requires a loudspeaker on one side of the particle. For the researchers, this means that it could be applied in the medical field for drug delivery. For those of us thinking of the future, this means that tractor beams on spaceships may be possible in a distant future. (Which the scientists did prove would work on a scaled down model.)


BBC News
Nature

Pluto Press Conference

Summary: It has been hard to miss the news of New Horizons flying past Pluto and getting beautiful images and data to send back to Earth. It has been harder to keep up with the constant flood of data that is pouring out. NASA has thankfully given a press conference and has published the highlights online.

Personally I am most overjoyed that they have nicknamed the dark spot on the top of Charon Mordor but I also love hearing about the giant ice cliffs. I will point you straight toward the mission site though to get all of the highlights.

If you have access to BBC, their program Sky at Night will be doing a big recap of all the news and what it means on the night of the 20th.


BBC News

Pluto through the years Credit: NASA

New particle seen at CERN

Summary: Nearly lost amid all the Pluto excitement, scientists at CERN have possibly discovered a new particle called the pentaquark. This new particle has been theorized to exist since the 60s and many have claimed to discover it before so they are being cautious. However, if this is indeed what is seems to be, then we have a new form of matter.

The pentaquark is a particle composed of four quarks and one antiquark.

Scientists found the particle by studying the way that the particle Lambda b decayed into three other particles. Some of the intermediary stages only made sense if the pentaquark did exist. Although still cautious about declaring this to be the pentaquark, the technology available to researchers at CERN allows them to view the problem in five dimensions rather than just one.

If this is indeed the particle they think it is, it will provide us with new ways of imagining quarks to be arranged and matter to be composed. Matter may be more complex than we thought.


BBC News

Quintuplet Stars

Summary: Our solar system features one star. There are many examples of binary star systems and even two binary stars coupled together. But astronomers have now found an incredibly rare new system. Two couples binary stars with one lonely companion star to make up a total of five stars.

Of the binaries, one is a detached pair and the other is coupled, meaning that the two stars share an outer atmosphere. Although there are no observations to prove it, it is possible that there are planets orbiting these stars. What a spectacular sky show they would have.


BBC News

Rise and Shine, Philae

Summary: Remember when there was a huge celebration because as a human race, we landed a rover on a comet? It was thrilling at the time, but we lost contact with the rover after it bounced into the shade of a cliff. Now the comet has tilted to allow sunlight to reach Philae and the rover has reached out to Earth.

A few very short message was received but it gives scientists hope and affirms that the rover may be able to still carry out its mission. There is not much else known at this point but the comet will be shifting into a position with more sunlight so more can be understood about the condition of the rover.


BBC News

The Case of the Strangled Galaxies

Summary: Galaxies are considered dead when they no longer are producing new stars. It is still unclear what causes this process but what astronomers do now know is the most common time scale of them dying -- approximately four billion years. Astronomers are calling this process strangulation.

Astronomers are able to tell how quickly the galaxy died based on the metal content remaining in the galaxy. The more stars that are being formed in a galaxy, the more metal content is seen. The way it works is simple. If a galaxy dies quickly and quite violently (for instance if the cool gas that fuels the star formation is suddenly ripped away), then the stars immediately stop producing and the metal content remains the same. But if the galaxy if cut off from the supply of cool gas but still continues to produce stars, using up the last of the supply, the metal content in the galaxy grows and grows until it "suffocates".

The difference was seen when comparing the spectra of light emitted by red, passive galaxies and blue, star-forming galaxies. With the data from Sloan they were able to see that the dead galaxies were, on average, four billion years older than the active galaxies. This is consistent with the amount of time the astronomers had calculated it would take to burn of the remaining amount of gas supply whilst strangling to death.

While the astronomers are now confident that death by strangulation is the most common way a galaxy meets it's ultimate end, it is still not clear what causes this. The most likely suspect at this point in time seems to be overcrowding which would lead to a greater probability of disruption to the gas supply, but this would need further investigation.



BBC News
Nature

LHC is Up and Running

Summary: After the scheduled two year shutdown and update of the Large Hadron Collider at CERN, the LHC is back and ready for even higher energy collisions. It began smashing particles again Easter Sunday at energies of 450 GeV. Amazingly enough, this is a lower energy and will be used for calibrations before the truly record breaking energies of 7,000 GeV starting on June 1st.


BBC News

Update: Test collisions have broken the energy record already at 13 TeV.

BBC News

A Shattering of Old Dark Matter Theories

Summary: Thanks to new data, further theories of the nature of dark matter have been smashed to pieces! Pardon me for being excited about leading theories being wrong but that only means that I may have a part to play in developing the correct theory. So what has changed?

It turns out dark matter really doesn't seem to interact with anything apart from gravity. It doesn't even interact with itself. The study was conducted my using the Hubble and Chandra to look at collisions of different galaxies and watch the dark matter. Well, it looked at the gravitational lensing since dark matter itself is essentially impossible to see.

In the way science should work, Dr. Massey explains that "if you want to figure out what something is made out of, you knock it, or you throw it across the room and see where the bits go." The surprising part was that unlike the stars that slide past each other and the gas clouds that come to a halt in these collisions, the dark matter "seems not to interact with anything at all." Rather like a ghost, it just glides through the other dark matter like it's no big deal. Since it doesn't even interact with itself, many prominent theories for what dark matter is has now fallen apart. Which means exciting new possibilities for the rest of us in the future. 


BBC News
Science Mag

Rosetta's Comet is Slowing Down

Summary: Despite the rover not being turned on again, astronomers are still learning new things about the chosen comet. For instance, it's changing rotation speed. The comet takes approximately 12.4 hours to complete one rotation, only that rate seems to be slowing down by one second per day. It seems like a small change but that is big in astronomical terms. It is actually a faster rate of change than in September. Back then it was slowing down by 33 milliseconds per day. (And right there is a differential equation for those who are so inclined.)

Scientists know the reason for this. The comet 67P is becoming more active which means there are gas jets shooting out of the rock and serving as propulsion, much like a rocket, only in the opposite direction of rotation, thus slowing it down. The jets actually shoot out of the comet at 800 meters per second and extend a few kilometers off the surface.

Astronomers found this out thanks to Rosetta still being in orbit around the rock. In order to keep the satellite in the correct trajectory, the navigators were using a system of landmarks on the surface to keep track of position. Only the landmarks were coming into view at a different time than expected.

BBC News

More Secret Oceans

Summary: Jupiter's moon Ganymede is the latest solar system body now thought to have a secret ocean lying beneath its icy crust. The evidence for this lies in the aurora produced by the moon's magnetosphere. The auroras are also influences by Jupiter, but not as much as scientists thought they should be. The presence of a salty ocean below the surface would counteract some if the effects of Jupiter and leave what we see now.

This new evidence means that we are past the point of ambiguity but not certain yet. We will know more when a probe in 2030 orbits the moon and finishes with a crash landing into the surface. 


BBC News

And Happy Pi Day!

Astronomical Updates

Highest Quality image of Ceres:
Ceres, the 950-km wide dwarf planet has a new image that is clearer than ever before. The resolution beats that of Hubble's image of Ceres. The cool thing is the image quality can only improve as Dawn approaches.

BBC News


New Horizons setting it's sights on Pluto:
The New Horizons probe will be zooming by Pluto on July 14th of this year but before it reaches the planet, it must start taking images to calibrate it's instruments and check its trajectory. The first images, with Pluto only as a tiny speck, should be released this week. Researchers are hoping that this mission will reveal many surprises about Pluto including new moons and possible rings.

BBC News


Large Asteroid and it's Moon:
The asteroid 2004 BL 86 was seen with a moon as it passed relatively close to Earth. The asteroid itself is 325m wide and it's moon is 70m wide.

BBC News

Lonely Stars

Summary: Two missions in 2010 and 2012 saw a rocket launched for a ten minute look at the Extragalactic Background Light (EBL) from above the atmosphere. What is the EBL? Professor Jaime Bock of JPL puts it this way: "It's very faint - but basically the spaces between the stars and galaxies aren't dark. And this is the total light made by stars and galaxies during cosmic history."

Having two separate data collecting missions that looked at different area of the sky allows the scientists to rule out fluctuations due to dust within our solar system. Even with this precaution, there was still extra light. The team believes that based on the brightness and blueness of the EBL, it shows that stars exist outside of galaxies. There might even be just as many stars outside galaxies as inside; it's that bright.

Of course other astronomers are skeptical of this conclusion. They concede it may be possible but are leaving their minds open for new and different possibilities.


BBC News
Science Mag

Where no Rover has gone Before

Summary: The landing was a success. Philae has landed on the comet 67P and is now confirmed to be stable. Scientists had been waiting overnight for this confirmation since it was known that the rover had some issues in landing. It actually landed three times due to one of the harpoons failing to attach to the surface. But all is now well and the mission can proceed. One of the main goals is to determine the composition of the comet and use this to learn more about the origins of our Solar System. Especially the question of whether it was from comets that we got our water and the beginnings of life. For a journey that took 10 years, an idea that was born 25 years ago, I hope everyone involved is proud of their success.


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