Our newest planet-hunting telescope is up and running at the ESO’s Paranal Observatory in the Atacama Desert in Chile. SPECULOOS, which stands for Planets EClipsing ULtra-cOOl Stars, is actually four 1-meter telescopes working together. The first images from the ‘scopes are in, and though it hasn’t found any other Earths yet, the images are still impressive.
Exotic dark matter theories. Gravitational waves. Observatories in space. Giant black holes. Colliding galaxies. Lasers. If you’re a fan of all the awesomest stuff in the universe, then this article is for you.
Update: Sept. 18th.
The mystery surrounding the closure of the Sunspot Solar Observatory has been (mostly) cleared up. After being closed and vacated on Sept. 6th due to an unspecified security threat, the facility is now open, and will resume normal scientific activities next week.
In a statement, Shari Lifson, spokesperson for the Association of Universities for Research in Astronomy (AURA), the body that operates the Sunspot Observatory, said that the facility was closed as a “precautionary measure.”
Astronomers have discovered the most distant supernova yet, at a distance of 10.5 billion light years from Earth. The supernova, named DES16C2nm, is a cataclysmic explosion that signaled the end of a massive star some 10.5 billion years ago. Only now is the light reaching us. The team of astronomers behind the discovery have published their results in a new paper available at arXiv.
“…sometimes you just have to go out and look up to find something amazing.” – Dr. Bob Nichol, University of Portsmouth.
The supernova was discovered by astronomers involved with the Dark Energy Survey (DES), a collaboration of astronomers in different countries. The DES’s job is to map several hundred million galaxies, to help us find out more about dark energy. Dark Energy is the mysterious force that we think is causing the accelerated expansion of the Universe.
DES16C2nm was first detected in August 2016. Its distance and extreme brightness were confirmed in October that year with three of our most powerful telescopes – the Very Large Telescope and the Magellan Telescope in Chile, and the Keck Observatory, in Hawaii.
DES16C2nm is what’s known as a superluminous supernova (SLSN), a type of supernova only discovered 10 years ago. SLSNs are the rarest—and the brightest—type of supernova that we know of. After the supernova exploded, it left behind a neutron star, which is the densest type of object in the universe. The extreme brightness of SLSNs, which can be 100 times brighter than other supernovae, are thought to be caused by material falling into the neutron star.
“It’s thrilling to be part of the survey that has discovered the oldest known supernova.” – Dr Mathew Smith, lead author, University of Southampton
Lead author of the study Dr Mathew Smith, of the University of Southampton, said: “It’s thrilling to be part of the survey that has discovered the oldest known supernova. DES16C2nm is extremely distant, extremely bright, and extremely rare – not the sort of thing you stumble across every day as an astronomer.”
Dr. Smith went on to say that not only is the discovery exciting just for being so distant, ancient, and rare. It’s also providing insights into the cause of SLSNs: “The ultraviolet light from SLSN informs us of the amount of metal produced in the explosion and the temperature of the explosion itself, both of which are key to understanding what causes and drives these cosmic explosions.”
“Now we know how to find these objects at even greater distances, we are actively looking for more of them as part of the Dark Energy Survey.” – Co-author Mark Sullivan, University of Southampton.
Now that the international team behind the Dark Energy Survey has found one of the SLSNs, they want to find more. Co-author Mark Sullivan, also of the University of Southampton, said: “Finding more distant events, to determine the variety and sheer number of these events, is the next step. Now we know how to find these objects at even greater distances, we are actively looking for more of them as part of the Dark Energy Survey.”
The instrument used by DES is the newly constructed Dark Energy Camera (DECam), which is mounted on the Victor M. Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory (CTIO) in the Chilean Andes. DECam is an extremely sensitive 570-megapixel digital camera designed and built just for the Dark Energy Survey.
The Dark Energy Survey involves more than 400 scientists from over 40 international institutions. It began in 2013, and will wrap up its five year mission sometime in 2018. The DES is using 525 nights of observation to carry out a deep, wide-area survey to record information from 300 million galaxies that are billions of light-years from Earth. DES is designed to help us answer a burning question.
According to Einstein’s General Relativity Theory, gravity should be causing the expansion of the universe to slow down. And we thought it was, until 1998 when astronomers studying distant supernovae found that the opposite is true. For some reason, the expansion is speeding up. There are really only two ways of explaining this. Either the theory of General Relativity needs to be replaced, or a large portion of the universe—about 70%—consists of something exotic that we’re calling Dark Energy. And this Dark Energy exerts a force opposite to the attractive force exerted by “normal” matter, causing the expansion of the universe to accelerate.
“…sometimes you just have to go out and look up to find something amazing.” – Dr. Bob Nichol, University of Portsmouth.
To help answer this question, the DES is imaging 5,000 square degrees of the southern sky in five optical filters to obtain detailed information about each of the 300 million galaxies. A small amount of the survey time is also used to observe smaller patches of sky once a week or so, to discover and study thousands of supernovae and other astrophysical transients. And this is how DES16C2nm was discovered.
Study co-author Bob Nichol, Professor of Astrophysics and Director of the Institute of Cosmology and Gravitation at the University of Portsmouth, commented: “Such supernovae were not thought of when we started DES over a decade ago. Such discoveries show the importance of empirical science; sometimes you just have to go out and look up to find something amazing.”
It’s been 20 years since the first of the four Unit Telescopes that comprise the ESO’s Very Large Telescope (VLT) saw first light. Since the year 2000 all four of them have been in operation. One of the original goals of the VLT was to have all four of the ‘scopes work in combination, and that has now been achieved.
The instrument that combines the light from all four of the VLT ‘scopes is called ESPRESSO, which stands for Echelle SPectrograph for Rocky Exoplanet and Stable Spectroscopic Observations. ESPRESSO captures the light from each of the 8.2 meter mirrors in the four Unit Telescopes of the VLT. That combination makes ESPRESSO, in effect, the largest optical telescope in the world.
Combining the power of the four Unit Telescopes of the VLT is a huge milestone for the ESO. As ESPRESSO instrument scientist at ESO, Gaspare Lo Curto, says, “ESO has realised a dream that dates back to the time when the VLT was conceived in the 1980s: bringing the light from all four Unit Telescopes on Cerro Paranal together at an incoherent focus to feed a single instrument!” The excitement is real, because along with its other science goals, ESPRESSO will be an extremely powerful planet-hunting telescope.
“ESO has realised a dream that dates back to the time when the VLT was conceived in the 1980s.” – Gaspare Lo Curto, ESPRESSO instrument scientist.
ESPRESSO uses a system of mirrors, lenses, and prisms to transmit the light from each of the four VLT ‘scopes to the spectrograph. This is accomplished with a network of tunnels that was incorporated into the VLT when it was built. ESPRESSO has the flexibility to combine the light from all four, or from any one of the telescopes. This observational flexibility was also an original design goal for ESPRESSO.
The four Unit Telescopes often operate together as the VLT Interferometer, but that’s much different than ESPRESSO. The VLT Interferometer allows astronomers to study extreme detail in bright objects, but it doesn’t combine the light from the four Unit Telescopes into one instrument. ESPRESSO collects the light from all four ‘scopes and splits it into its component colors. This allows detailed analysis of the composition of distant objects.
ESPRESSO is a very complex instrument, which explains why it’s taken until now to be implemented. It works with a principle called “incoherent focus.” In this sense, “incoherent” means that the light from all four telescopes is added together, but the phase information isn’t included as it is with the VLT Interferometer. What this boils down to is that while both the VLT Interferometer and ESPRESSO both use the light of all four VLT telescopes, ESPRESSO only has the spatial resolution of a single 8.2 mirror. ESPRESSO, as its name implies, is all about detailed spectrographic analysis. And in that, it will excel.
“ESPRESSO working with all four Unit Telescopes gives us an enticing foretaste of what the next generation of telescopes, such as ESO’s Extremely Large Telescope, will offer in a few years.” – ESO’s Director General, Xavier Barcons
ESPRESSO is the successor to HARPS, the High Accuracy Radial velocity Planet Searcher, which up until now has been our best exoplanet hunter. HARPS is a 3.6 meter telescope operated by the ESO, and also based on an echelle spectrograph. But the power of ESPRESSO will dwarf that of HARPS.
There are three main science goals for ESPRESSO:
- Planet Hunting
- Measuring the Variation of the Fundamental Physical Constants
- Analyzing the Chemical Composition of Stars in Nearby Galaxies
ESPRESSO will take highly precise measurements of the radial velocities of solar type stars in other solar systems. As an exoplanet orbits its star, it takes part in a dance or tug-of-war with the star, the same way planets in our Solar System do with our Sun. ESPRESSO will be able to measure very small “dances”, which means it will be able to detect very small planets. Right now, our planet-hunting instruments aren’t as sensitive as ESPRESSO, which means our exoplanet search results are biased to larger planets. ESPRESSO should detect more smaller, Earth-size planets.
Measuring the Variation of the Fundamental Physical Constants
This is where the light-combining power of ESPRESSO will be most useful. ESPRESSO will be used to observe extremely distant and faint quasars, to try and measure the variation of the fundamental physical constants in our Universe. (If there are any variations, that is.) It’s not only the instrument’s light-combining capability that allows this, but also the instrument’s extreme stability.
Specifically, the ESPRESSO will try to take our most accurate measurements yet of the fine structure constant, and the proton to electron mass ratio. Astronomers want to know if these have changed over time. They will use ESPRESSO to examine the ancient light from these distant quasars to measure any change.
Analyzing the Chemical Composition of Stars in Nearby Galaxies
ESPRESSO will open up new possibilities in the measurement of stars in nearby galaxies. It’s high efficiency and high resolution will allow astronomers to study stars outside of the Milky Way in unprecedented detail. A better understanding of stars in other galaxies is always a priority item in astronomy.
We’ll let Project Scientist Paolo Molaro have the last word, for now. “This impressive milestone is the culmination of work by a large team of scientists and engineers over many years. It is wonderful to see ESPRESSO working with all four Unit Telescopes and I look forward to the exciting science results to come.”
Ever since the Kepler space telescope began discovering thousands of exoplanets in our galaxy, astronomers have been eagerly awaiting the day when next-generation missions are deployed. These include the much-anticipated James Webb Space Telescope, which is scheduled to take to space in 2019, but also the many ground-based observatories that are currently being constructed.
One of these is the Exoplanets in Transits and their Atmospheres (ExTrA) project, which is the latest addition to the ESO’s La Silla Observatory in Chile. Using the Transit Method, this facility will rely on three 60-centimeter (23.6 in) telescopes to search for Earth-sized exoplanets around M-type (red dwarf) stars in the Milky Way Galaxy. This week, the facility began by collecting its first light.
The Transit Method (aka. Transit Photometry) consists of monitoring stars for periodic dips in brightness. These dips are caused by planets passing in front of the star (aka. transiting) relative to the observer. In the past, detecting planets around M-type stars using this method has been challenging since red dwarfs are the smallest and dimmest class of star in the known Universe and emit the majority of their light in the near-infrared band.
However, these stars have also proven to be treasure trove when it comes to rocky, Earth-like exoplanets. In recent years, rocky planets have been discovered around star’s like Proxima Centauri and Ross 128, while TRAPPIST-1 had a system of seven rocky planets. In addition, there have been studies that have indicated that potentially-habitable, rocky planets could be very common around red dwarf stars.
Unlike other facilities, the ExTrA project is well-suited to conduct surveys for planets around red dwrfs because of its location on the outskirts of the Atacama Desert in Chile. As Xavier Bonfils, the project’s lead researcher, explained:
“La Silla was selected as the home of the telescopes because of the site’s excellent atmospheric conditions. The kind of light we are observing – near-infrared – is very easily absorbed by Earth’s atmosphere, so we required the driest and darkest conditions possible. La Silla is a perfect match to our specifications.”
In addition, the ExTrA facility will rely on a novel approach that involves combining optical photometry with spectroscopic information. This consists of its three telescopes collecting light from a target star and four companion stars for comparison. This light is then fed through optical fibers into a multi-object spectrograph in order to analyze it in many different wavelengths.
This approach increases the level of achievable precision and helps mitigate the disruptive effect of Earth’s atmosphere, as well as the potential for error introduced by instruments and detectors. Beyond the goal of simply finding planets transiting in front of their red dwarf stars, the ExTrA telescopes will also study the planets it finds in order to determine their compositions and their atmospheres.
In short, it will help determine whether or not these planets could truly be habitable. As Jose-Manuel Almenara, a member of the ExTrA team, explained:
“With ExTrA, we can also address some fundamental questions about planets in our galaxy. We hope to explore how common these planets are, the behaviour of multi-planet systems, and the sorts of environments that lead to their formation,”
The potential to search for extra-solar planets around red dwarf stars is an immense opportunity for astronomers. Not only are they the most common star in the Universe, accounting for 70% of stars in our galaxy alone, they are also very long-lived. Whereas stars like our Sun have a lifespan of about 10 billion years, red dwarfs are capable of remaining in their main sequence phase for up to 10 trillion years.
For these reasons, there are those who think that M-type stars are our best bet for finding habitable planets in the long run. At the same time, there are unresolved questions about whether or not planets that orbit red dwarf stars can stay habitable for long, owing to their variability and tendency to flare up. But with ExTrA and other next-generation instruments entering into service, astronomers may be able to address these burning questions.
As Bonfils excitedly put it:
“With the next generation of telescopes, such as ESO’s Extremely Large Telescope, we may be able to study the atmospheres of exoplanets found by ExTra to try to assess the viability of these worlds to support life as we know it. The study of exoplanets is bringing what was once science fiction into the world of science fact.”
ExTrA is a French project funded by the European Research Council and the French Agence National de la Recherche and its telescopes will be operated remotely from Grenoble, France. Also, be sure to enjoy this video of the ExTrA going online, courtesy of the ESOcast:
Further Reading: ESO
There’s nothing an astronomer – whether professional or amateur – loves more than a clear dark night sky away from the city lights. Outside the glare and glow and cloud cover that most of us experience every day, the night sky comes alive with a life of its own.
Thousands upon countless thousands of glittering jewels – each individual star a pinprick of light set against the velvet-smooth blackness of the deeper void. The arching band of the Milky Way, itself host to billions more stars so far away that we can only see their combined light from our vantage point. The familiar constellations, proudly showing their true character, drawing the eye and the mind to the ancient tales spun about them.
There are few places left in the world to see the sky as our ancestors did; to gaze in wonder at the celestial dome and feel the weight of billions of years of cosmic history hanging above us. Thankfully the International Dark Sky Association is working to preserve what’s left of the true night sky, and they’ve rightfully marked northern Chile to preserve for posterity.
The fifth mirror for the Giant Magellan Telescope (GMT) is now being cast, according to an announcement from the Giant Magellan Telescope Organization (GMTO), the body behind the project. The GMT is a ground-breaking segmented telescope consisting of 7 gigantic mirrors, and is being built at the Las Campanas Observatory, in Atacama, Chile.
The mirrors for the GMT are being cast at the Richard F. Caris Mirror Laboratory, at the University of Arizona. This lab is the world centre when it comes to building large mirrors for telescopes. But in a lab known for ground-breaking, precision manufacturing, the GMT’s mirrors are pushing the engineering to its limits.
Seven separate mirrors, each the same size (8.4 meters,) will make up the GMT’s primary mirror. One mirror will be in the centre, and six will be arranged in a circle around it. Each one of these mirrors is a 20 ton glass behemoth, and each one is cast separately. Once the seven are manufactured (and one extra, just in case) they will be assembled at the observatory site.
The result will be an optical, light-gathering surface almost 24.5 meters (80 ft.) in diameter. That is an enormous telescope, and it’s taking extremely precise engineering and manufacturing to build these mirrors.
The glass for the mirrors is custom-manufactured, low-expansion glass from Japan. This glass comes as blocks, and each mirror requires exactly 17,481 kg of these glass blocks. A custom built furnace and mold heats the glass to 1165°C (2129°F) for several hours. The glass liquefies and flows into the mold. During this time, the mold is rotated at up to 5 rpm. Then the rotation is slowed, and for several months the glass cools in the mold.
After lengthy cooling, the glass can be polished. The tolerances for the mirrors, and the final shape they must take, requires very careful, extremely accurate polishing. The first mirror was cast in 2005, and in 2011 it was still being polished.
The mirrors for the GMT are not flat; they’re described as “potato chips.” They’re aspherical and parabaloidal. They have to be surface polished to an accuracy of 25 nanometers, which is a fraction of the wavelength of light.
“Casting the mirrors for the Giant Magellan Telescope is a huge undertaking, and we are very proud of the UA’s leading role creating this new resource for scientific discovery. The GMT partnership and Caris Mirror Lab are outstanding examples of how we can tackle complex challenges with innovative solutions,” said UA President Robert C. Robbins. “The University of Arizona has such an amazing tradition of excellence in space exploration, and I have been constantly impressed by the things our faculty, staff, and students in astronomy and space sciences can accomplish.”
Mirror construction for the GMT is a multi-stage process. The first mirror was completed several years ago and is in storage. Three others are in various stages of grinding and polishing. The glass for mirror 6 is in storage awaiting casting, and the glass for mirror 7 is on order from Japan.
Once completed, the GMT will be situated in Atacama, at the Las Campanas Observatory, where high-elevation and clear skies make for excellent seeing conditions. First light is planned for the mid 2020’s.
“Creating the largest telescope in history is a monumental endeavor, and the GMT will be among the largest privately-funded scientific initiatives to date,” said Taft Armandroff, Professor of Astronomy and Director of the McDonald Observatory at The University of Texas at Austin, and Vice-Chair of the GMTO Corporation Board of Directors. “With this next milestone, and with the leadership, technical, financial and scientific prowess of the members of the GMTO partnership, we continue on the path to the completion of this great observatory.”
The power of the GMT will allow it to directly image extra-solar planets. That alone is enough to get anyone excited. But the GMT will also study things like the formation of stars, planets, and disks; the assembly and evolution of galaxies; fundamental physics; and first light and re-ionization.
The Giant Magellan Telescope is one of the world’s Super Telescopes that we covered in this series of articles. The Super Telescopes include the:
- Giant Magellan Telescope
- James Webb Space Telescope
- Thirty Meter Telescope
- European Extremely Large Telescope
- Large Synoptic Survey Telescope
- Wide Field Infrared Survey Telescope
About 130 million years ago, in a galaxy far away, two neutron stars collided. The cataclysmic crash produced gravitational waves, ripples in the fabric of space and time. This event is now the 5th observation of gravitational waves by the Laser Interferometer Gravitational wave Observatory (LIGO) and Virgo collaboration, and the first detected that was not caused by the collision of two black holes.
But this event — called a kilonova — produced something else too: light, across multiple wavelengths.
For the first time in history, an astronomical phenomenon has been first observed through gravitational waves and then seen with telescopes. In an incredibly collaborative effort, over 3,500 astronomers using 100 instruments on over 70 telescopes around the world and in space worked with physicists from the LIGO and Virgo collaboration.
Scientists call this “multimessenger astronomy.”
“Together, all these observations are bigger than the sum of their parts,” said Laura Cadonati, LIGO’s Deputy Spokesperson at a briefing today. “We are now learning about the physics of the universe, about the elements we are made of, in a way that no one has ever done before.”
“It will give us insight into how supernova explosions work, how gold and other heavy elements are created, how the nuclei in our body works and even how fast the universe is expanding,” said Manuela Campanelli, from the Rochester Institute of Technology. “Multimessenger astronomy demonstrates how we can combine the old way with the new. It has changed the way astronomy is done.”
Neutron stars are the crushed leftover cores of massive stars that long ago exploded as supernovae. The two stars, located near each other in a galaxy called NGC 4993, started out between 8-20 times the mass of our sun. Then with their supernovas, each condensed down to about 10 miles in diameter, the size of a city. These are stars composed entirely of neutrons and are in-between normal stars and black holes in size and density — just a teaspoon of neutron star material would weigh 1 billion tons.
They spun around each other in a cosmic dance until their mutual gravity caused them to collide. That collision produced a fireball of astronomical proportions and the repercussions of that event arrived at Earth 130 million years later.
“While this event took place 130 million years ago, we only found out about this on Earth on August 17, 2017, just before the solar eclipse,” said Andy Howell from the Las Cumbres Observatory, speaking at a press briefing today. “We’ve been keeping this secret the whole time and we’re about to bust!”
At 8:41 am EDT, LIGO and Virgo felt the early tremors of the ripples of spacetime, gravitational waves. Just two seconds later, a bright flash of gamma rays was detected by NASA’s Fermi space telescope. This allowed researchers to quickly pinpoint the direction from which the waves were coming.
Alerted by an Astronomers Telegram, thousands of astronomers around the world scrambled to make observations and begin collecting additional data from the neutron star merger.
This animation shows how LIGO, Virgo, and space- and ground-based telescopes zoomed in on the location of gravitational waves detected August 17, 2017 by LIGO and Virgo. By combining data from the Fermi and Integral space missions with data from LIGO and Virgo, scientists were able to confine the source of the waves to a 30-square-degree sky patch. Visible-light telescopes searched a large number of galaxies in that region, ultimately revealing NGC 4993 to be the source of gravitational waves.
“This event has the most precise sky localization of all detected gravitational waves so far,” Jo van den Brand, spokesperson for the Virgo collaboration, said in a statement. “This record precision enabled astronomers to perform follow-up observations that led to a plethora of breathtaking results.”
This provides the first real evidence that light and gravitational waves travel at the same speeds – near the speed of light — as Einstein predicted.
Observatories from the very small to the most well-known were involved, quickly making observations. While bright at first, the event faded in less than 6 days. Howell said the observed light was 2 million times brighter than the Sun over the course of the first few hours, but it then faded over a few days.
The Dark Energy Camera (DECam), which is mounted on the Blanco 4-meter Telescope at the Cerro Tololo Inter-American Observatory in the Chilean Andes was one of the instruments that helped localize the source of the event.
“The challenge that we face every time that the LIGO collaboration issues a new observational trigger is how do we search for a source that is rapidly fading, was possibly faint to begin with, and is located somewhere over there,” said Marcelle Soares-Santos, from Brandeis University at the briefing. She is the first author on the paper describing the optical signal associated with the gravitational waves. “It’s the classical challenge of finding a needle in a haystack with the added complication that the needle is far away and haystack is moving.”
With the DECam, they were quickly able to determine the source galaxy, and rule out 1,500 other candidates that were present in that haystack.
“Things that look like these ‘nneedles’ are very common, so we need to make sure we have the right one. Today, we are certain we have,” Soares-Santos added.
In the very small department, a small robotic 16-inch telescope called PROMPT (Panchromatic Robotic Optical Monitoring and Polarimetry Telescope) — which astronomer David Sand from the University of Arizona described at “basically a souped-up amateur telescope,” — also helped determine the source. Sand said this proves that even small telescopes can play a roll in multimessenger astronomy.
The well known is led by Hubble and several other NASA and ESA space observatories, such as the Swift, Chandra and Spitzer missions. Hubble captured images of the galaxy in visible and infrared light, witnessing a new bright object within NGC 4993 that was brighter than a nova but fainter than a supernova. The images showed that the object faded noticeably over the six days of the Hubble observations. Using Hubble’s spectroscopic capabilities the teams also found indications of material being ejected by the kilonova as fast as one-fifth of the speed of light.
“This is a game-changer for astrophysics,” said Howell. “A hundred years after Einstein theorized gravitational waves, we’ve seen them and traced them back to their source to find an explosion with new physics of the kind we only dreamed about before.”
Here are just a few of insights this single event created, using multimessenger astronomy:
* Gamma rays: These flashes of light are now definitively associated with merging neutron stars and will help scientists figure out how supernova explosions work, explained Richard O’Shaughnessy, also from Rochester Institute of Technology and a member of the LIGO team. “The initial gamma-ray measurements, combined with the gravitational-wave detection, further confirm Einstein’s general theory of relativity, which predicts that gravitational waves should travel at the speed of light,” he said.
* The source of gold and platinum: “These observations reveal the direct fingerprints of the heaviest elements in the periodic table,” said Edo Berger, from the Harvard Smithsonian Center for Astrophysics, speaking at the briefing. “The collision of the two neutron stars produced 10 times of mass of Earth in gold and platinum alone. Think about how as these materials are flying out of this event, they eventually combine with other elements to form stars, planets, life … and jewelry.”
Berger added something else to think about: the original supernova explosions of these stars produced all the heavy elements up to iron and nickel. Then in the kilonova in this one system, we can see the complete history of how the periodocial table of the heavy elements came into being.
Howell said that when you split the signatures of the heavy elements into a spectrum, you create a rainbow. “So there really was a pot of gold at the end of the rainbow, at least a kilonova rainbow,” he joked.
* Nuclear physics astronomy: “Eventually, more observations like this discovery will tell us how the nuclei in our body works,” O’Shaughnessy said. “The effects of gravity on neutron stars will tell us how big balls of neutrons behave, and, by inference, little balls of neutrons and protons — the stuff inside of our body that makes up most of our mass”; and
* Cosmology:- “Scientists now can independently measure how fast the universe is expanding by comparing the distance to the galaxy containing the bright flare of light and distance inferred from our gravitational wave observation,” said O’Shaughnessy.
“The ability to study the same event with both gravitational waves and light is a real revolution in astronomy,” said astronomer Tony Piro from the CfA. “We can now study the universe with completely different probes, which teaches things we could never know with only one or the other.”
“For me, what made this event so amazing is that not only did we detect gravitational waves, but we saw light across the electromagnetic spectrum, seen by 70 observatories around the world,” said David Reitz, scientific spokesman for LIGO, at today’s press briefing. “This is the first time the cosmos has provided to us the equivalent of movies with sound. The video is the observational astronomy across various wavelengths and the sound is gravitational waves.”
The Standard Model of particle physics has been the predominant means of explaining what the basic building blocks of matter are and how they interact for decades. First proposed in the 1970s, the model claims that for every particle created, there is an anti-particle. As such, an enduring mystery posed by this model is why the Universe can exist if it is theoretically made up of equal parts of matter and antimatter.
This seeming disparity, known as the charge-parity (CP) violation, has been the subject of experiments for many years. But so far, no definitive demonstration has been made for this violation, or how so much matter can exist in the Universe without its counterpart. But thanks to new findings released by the international Tokai-to-Kamioka (T2K) collaboration, we may be one step closer to understanding why this disparity exists.
First observed in 1964, CP violation proposes that under certain conditions, the laws of charge-symmetry and parity-symmetry (aka. CP-symmetry) do not apply. These laws state that the physics governing a particle should be the same if it were interchanged with its antiparticle, while its spatial coordinates would be inverted. From this observation, one of the greatest cosmological mysteries emerged.
If the laws governing matter and antimatter are the same, then why is it that the Universe is so matter-dominated? Alternately, if matter and antimatter are fundamentally different, then how does this accord with our notions of symmetry? Answering these questions is not only important as far as our predominant cosmological theories go, they are also intrinsic to understanding how the weak interactions that govern particles work.
Established in June of 2011, the international T2K collaboration is the first experiment in the world dedicated to answering this mystery by studying neutrino and anti-neutrino oscillations. The experiment begins with high-intensity beams of muon neutrinos (or muon anti-neutrinos) being generated at the Japan Proton Accelerator Research Complex (J-PARC), which are then fired towards the Super-Kamiokande detector 295 km away.
This detector is currently one of the world’s largest and most sophisticated, dedicated to the detection and study of solar and atmospheric neutrinos. As neutrinos travel between the two facilities, they change “flavor” – going from muon neutrinos or anti-neutrinos to electron neutrinos or anti-neutrinos. In monitoring these neutrino and anti-neutrino beams, the experiment watches for different rates of oscillation.
This difference in oscillation would show that there is an imbalance between particles and antiparticles, and thus provide the first definitive evidence of CP violation for the first time. It would also indicate that there are physics beyond the Standard Model that scientists have yet to probe. This past April, the first data set produced by T2K was released, which provided some telling results.
As Mark Hartz, a T2K collaborator and the Kavli IPMU Project Assistant Professor, said in a recent press release:
“While the data sets are still too small to make a conclusive statement, we have seen a weak preference for large CP violation and we are excited to continue to collect data and make a more sensitive search for CP violation.”
These results, which were recently published in the Physical Review Letters, include all data runs from between January 2010 to May 2016. In total, this data comprised 7.482 x 1020 protons (in neutrino mode), which yielded 32 electron neutrino and 135 muon neutrino events, and 7.471×1020 protons (in antineutrino mode), which yielded 4 electron anti-neutrino and 66 muon neutrino events.
In other words, the first batch of data has provided some evidence for CP violation, and with a confidence interval of 90%. But this is just the beginning, and the experiment is expected to run for another ten years before wrapping up. “If we are lucky and the CP violation effect is large, we may expect 3 sigma evidence, or about 99.7% confidence level, for CP violation by 2026,” said Hartz.
If the experiment proves successful, physicists may finally be able to answer how it is that the early Universe didn’t annihilate itself. It is also likely help to reveal aspects of the Universe that particle physicists are anxious to get into! For it here that the answers to the deepest secrets of the Universe, like how all of its fundamental forces fit together, are likely to be found.