The Spallation Neutron Source, located at the Oak Ridge National Laboratory. Credit: neutrons.ornl.gov
Neutrinos are one of the fundamental particles that make up the Universe. Compared to other types of particles, they have very little mass, no charge, and only interact with others via the weak nuclear force and gravity. As such, finding evidence of their interactions is extremely difficult, requiring massive instruments located deep underground to shield them from any interference.
However, using the Spallation Neutron Source (SNS), a research facility located at the Oak Ridge National Laboratory (ORNL) – an international team of researchers recently made a historic discovery about neutrinos using an entirely different method. As part of the COHERENT experiment, these results confirm a prediction made 43 years ago and offers new possibilities for neutrino research.
Just a couple of weeks ago, astronomers from Caltech announced their third detection of gravitational waves from the Laser Interferometer Gravitational-Wave Observatory or LIGO.
As with the previous two detections, astronomers have determined that the waves were generated when two intermediate-mass black holes slammed into each other, sending out ripples of distorted spacetime.
One black hole had 31.2 times the mass of the Sun, while the other had 19.4 solar masses. The two spiraled inward towards each other, until they merged into a single black hole with 48.7 solar masses. And if you do the math, twice the mass of the Sun was converted into gravitational waves as the black holes merged.
On January 4th, 2017, LIGO detected two black holes merging into one. Courtesy Caltech/MIT/LIGO Laboratory
These gravitational waves traveled outward from the colossal collision at the speed of light, stretching and compressing spacetime like a tsunami wave crossing the ocean until they reached Earth, located about 2.9 billion light-years away.
The waves swept past each of the two LIGO facilities, located in different parts of the United States, stretching the length of carefully calibrated laser measurements. And from this, researchers were able to detect the direction, distance and strength of the original merger.
Seriously, if this isn’t one of the coolest things you’ve ever heard, I’m clearly easily impressed.
Now that the third detection has been made, I think it’s safe to say we’re entering a brand new field of gravitational astronomy. In the coming decades, astronomers will use gravitational waves to peer into regions they could never see before.
Being able to perceive gravitational waves is like getting a whole new sense. It’s like having eyes and then suddenly getting the ability to perceive sound.
This whole new science will take decades to unlock, and we’re just getting started.
As Einstein predicted, any mass moving through space generates ripples in spacetime. When you’re just walking along, you’re actually generating tiny ripples. If you can detect these ripples, you can work backwards to figure out what size of mass made the ripples, what direction it was moving, etc.
Even in places that you couldn’t see in any other way. Let me give you a couple of examples.
Black holes, obviously, are the low hanging fruit. When they’re not actively feeding, they’re completely invisible, only detectable by how they gravitational attract objects or bend light from objects passing behind them.
But seen in gravitational waves, they’re like ships moving across the ocean, leaving ripples of distorted spacetime behind them.
With our current capabilities through LIGO, astronomers can only detect the most massive objects moving at a significant portion of the speed of light. A regular black hole merger doesn’t do the trick – there’s not enough mass. Even a supermassive black hole merger isn’t detectable yet because these mergers seem to happen too slowly.
LIGO has already significantly increased the number of black holes with known masses. The observatory has definitively detected two sets of black hole mergers (bright blue). For each event, LIGO determined the individual masses of the black holes before they merged, as well as the mass of the black hole produced by the merger. The black holes shown with a dotted border represent a LIGO candidate event that was too weak to be conclusively claimed as a detection. Credit: LIGO/Caltech/Sonoma State (Aurore Simonnet)
This is why all the detections so far have been intermediate-mass black holes with dozens of times the mass of our Sun. And we can only detect them at the moment that they’re merging together, when they’re generating the most intense gravitational waves.
If we can boost the sensitivity of our gravitational wave detectors, we should be able to spot mergers of less and more massive black holes.
But merging isn’t the only thing they do. Black holes are born when stars with many more times the mass of our Sun collapse in on themselves and explode as supernovae. Some stars, we’ve now learned just implode as black holes, never generating the supernovae, so this process happens entirely hidden from us.
Is there a singularity at the center of a black hole event horizon, or is there something there, some kind of object smaller than a neutron star, but bigger than an infinitely small point? As black holes merge together, we could see beyond the event horizon with gravitational waves, mapping out the invisible region within to get a sense of what’s going on down there.
This illustration shows the merger of two black holes and the gravitational waves that ripple outward as the black holes spiral toward each other. In reality, the area near the black holes would appear highly warped, and the gravitational waves would be difficult to see directly. Credit: LIGO/T. Pyle
We want to know about even less massive objects like neutron stars, which can also form from a supernova explosion. These neutron stars can orbit one another and merge generating some of the most powerful explosions in the Universe: gamma ray bursts. But do neutron stars have surface features? Different densities? Could we detect a wobble in the gravitational waves in the last moments before a merger?
And not everything needs to merge. Sensitive gravitational wave detectors could sense binary objects with a large imbalance, like a black hole or neutron star orbiting around a main sequence star. We could detect future mergers by their gravitational waves.
Are gravitational waves a momentary distortion of spacetime, or do they leave some kind of permanent dent on the Universe that we could trace back? Will we see echoes of gravity from gravitational waves reflecting and refracting through the fabric of the cosmos?
Perhaps the greatest challenge will be using gravitational waves to see beyond the Cosmic Microwave Background Radiation. This region shows us the Universe 380,000 years after the Big Bang, when everything was cool enough for light to move freely through the Universe.
But there was mass there, before that moment. Moving, merging mass that would have generated gravitational waves. As we explained in a previous article, astronomers are working to find the imprint of these gravitational waves on the Cosmic Microwave Background, like an echo, or a shadow. Perhaps there’s a deeper Cosmic Gravitational Background Radiation out there, one which will let us see right to the beginning of time, just moments after the Big Bang.
And as always, there will be the surprises. The discoveries in this new field that nobody ever saw coming. The “that’s funny” moments that take researchers down into whole new fields of discovery, and new insights into how the Universe works.
The Laser Interferometer Gravitational-Wave Observatory (LIGO) facility in Livingston, Louisiana. The other facility is located in Hanford, Washington. Image: LIGO
The LIGO project was begun back in 1994, and the first iteration operated from 2002 to 2012 without a single gravitational wave detection. It was clear that the facility wasn’t sensitive enough, so researchers went back and made massive improvements.
In 2008, they started improving the facility, and in 2015, Advanced LIGO came online with much more sensitivity. With the increased capabilities, Advanced LIGO made its first discovery in 2016, and now two more discoveries have been added.
LIGO can currently only detect the general hemisphere of the sky where a gravitational wave was emitted. And so, LIGO’s next improvement will be to add another facility in India, called INDIGO. In addition to improving the sensitivity of LIGO, this will give astronomers three observations of each event, to precisely detect the origin of the gravitational waves. Then visual astronomers could do follow up observations, to map the event to anything in other wavelengths.
Current operating facilities in the global network include the twin LIGO detectors—in Hanford, Washington, and Livingston, Louisiana—and GEO600 in Germany. The Virgo detector in Italy and the Kamioka Gravitational Wave Detector (KAGRA) in Japan are undergoing upgrades and are expected to begin operations in 2016 and 2018, respectively. A sixth observatory is being planned in India. Having more gravitational-wave observatories around the globe helps scientists pin down the locations and sources of gravitational waves coming from space. Image made in February 2016. Credit: Caltech/MIT/LIGO Lab
A European experiment known as Virgo has been operating for a few years as well, agreeing to collaborate with the LIGO team if any detections are made. So far, the Virgo experiment hasn’t found anything, but it’s being upgraded with 10 times the sensitivity, which should be fully operational by 2018.
A Japanese experiment called the Kamioka Gravitational Wave Detector, or KAGRA, will come online in 2018 as well, and be able to contribute to the observations. It should be capable of detecting binary neutron star mergers out to nearly a billion light-years away.
Just with visual astronomy, there are a set of next generation supergravitational wave telescopes in the works, which should come online in the next few decades.
The Europeans are building the Einstein Telescope, which will have detection arms 10 km long, compared to 4 km for LIGO. That’s like, 6 more km.
There’s the European Space Agency’s space-based Laser Interferometer Space Antenna, or LISA, which could launch in 2030. This will consist of a fleet of 3 spacecraft which will maintain a precise distance of 2.5 million km from each other. Compare that to the Earth-based detection distances, and you can see why the future of observations will come from space.
The Laser Interferometer Space Antenna (LISA) consists of three spacecraft orbiting the sun in a triangular configuration. Credit: NASA
And that last idea, looking right back to the beginning of time could be a possibility with the Big Bang Observer mission, which will have a fleet of 12 spacecraft flying in formation. This is still all in the proposal stage, so no concrete date for if or when they’ll actually fly.
Gravitational wave astronomy is one of the most exciting fields of astronomy. This entirely new sense is pushing out our understanding of the cosmos in entirely new directions, allowing us to see regions we could never even imagine exploring before. I can’t wait to see what happens next.
Whenever we talk about the expanding Universe, everyone wants to know how this is going to end. Sure, they say, the fact that most of the galaxies we can see are speeding away from us in all directions is really interesting. Sure, they say, the Big Bang makes sense, in that everything was closer together billions of years ago.
But how does it end? Does this go on forever? Do galaxies eventually slow down, come to a stop, and then hurtle back together in a Big Crunch? Will we get a non-stop cycle of Big Bangs, forever and ever?
The Big Bang Theory: A history of the Universe starting from a singularity and expanding ever since. Credit: grandunificationtheory.com
We’ve done a bunch of articles on many different aspects of this question, and the current conclusion astronomers have reached is that because the Universe is flat, it’s never going to collapse in on itself and start another Big Bang.
But wait, what does it mean to say that the Universe is “flat”? Why is that important, and how do we even know?
Before we can get started talking about the flatness of the Universe, we need to talk about flatness in general. What does it mean to say that something is flat?
If you’re in a square room and walk around the corners, you’ll return to your starting point having made 4 90-degree turns. You can say that your room is flat. This is Euclidian geometry.
Earth, seen from space, above the Pacific Ocean. Credit: NASA
But if you make the same journey on the surface of the Earth. Start at the equator, make a 90-degree turn, walk up to the North Pole, make another 90-degree turn, return to the equator, another 90-degree turn and return to your starting point.
In one situation, you made 4 turns to return to your starting point, in another situation it only took 3. That’s because the topology of the surface you were walking on decided what happens when you take a 90-degree turn.
You can imagine an even more extreme example, where you’re walking around inside a crater, and it takes more than 4 turns to return to your starting point.
Another analogy, of course, is the idea of parallel lines. If you fire off two parallel lines at the North pole, they move away from each other, following the topology of the Earth and then come back together.
Got that? Great.
Omega Centauri. Credits: NASA, ESA and the Hubble SM4 ERO Team
Now, what about the Universe itself? You can imagine that same analogy. Imaging flying out into space on a rocket for billions of light-years, performing 90-degree maneuvers and returning to your starting point.
You can’t do it in 3, or 5, you need 4, which means that the topology of the Universe is flat. Which is totally intuitive, right? I mean, that would be your assumption.
But astronomers were skeptical and needed to know for certain, and so, they set out to test this assumption.
In order to prove the flatness of the Universe, you would need to travel a long way. And astronomers use the largest possible observation they can make. The Cosmic Microwave Background Radiation, the afterglow of the Big Bang, visible in all directions as a red-shifted, fading moment when the Universe became transparent about 380,000 years after the Big Bang.
Cosmic Microwave Background Radiation. Image credit: NASA
When this radiation was released, the entire Universe was approximately 2,700 C. This was the moment when it was cool enough for photons were finally free to roam across the Universe. The expansion of the Universe stretched these photons out over their 13.8 billion year journey, shifting them down into the microwave spectrum, just 2.7 degrees above absolute zero.
With the most sensitive space-based telescopes they have available, astronomers are able to detect tiny variations in the temperature of this background radiation.
And here’s the part that blows my mind every time I think about it. These tiny temperature variations correspond to the largest scale structures of the observable Universe. A region that was a fraction of a degree warmer become a vast galaxy cluster, hundreds of millions of light-years across.
Having a non-flat universe would cause distortions between what we saw in the CMBR compared to the current universe. Credit: NASA / WMAP Science Team
The Cosmic Microwave Background Radiation just gives and gives, and when it comes to figuring out the topology of the Universe, it has the answer we need. If the Universe was curved in any way, these temperature variations would appear distorted compared to the actual size that we see these structures today.
But they’re not. To best of its ability, ESA’s Planck space telescope, can’t detect any distortion at all. The Universe is flat.
Illustration of the ESA Planck Telescope in Earth orbit (Credit: ESA)
Well, that’s not exactly true. According to the best measurements astronomers have ever been able to make, the curvature of the Universe falls within a range of error bars that indicates it’s flat. Future observations by some super Planck telescope could show a slight curvature, but for now, the best measurements out there say… flat.
We say that the Universe is flat, and this means that parallel lines will always remain parallel. 90-degree turns behave as true 90-degree turns, and everything makes sense.
But what are the implications for the entire Universe? What does this tell us?
Unfortunately, the biggest thing is what it doesn’t tell us. We still don’t know if the Universe is finite or infinite. If we could measure its curvature, we could know that we’re in a finite Universe, and get a sense of what its actual true size is, out beyond the observable Universe we can measure.
The observable – or inferrable universe. This may just be a small component of the whole ball game.
We know that the volume of the Universe is at least 100 times more than we can observe. At least. If the flatness error bars get brought down, the minimum size of the Universe goes up.
And remember, an infinite Universe is still on the table.
Another thing this does, is that it actually causes a problem for the original Big Bang theory, requiring the development of a theory like inflation.
Since the Universe is flat now, it must have been flat in the past, when the Universe was an incredibly dense singularity. And for it to maintain this level of flatness over 13.8 billion years of expansion, in kind of amazing.
In fact, astronomers estimate that the Universe must have been flat to 1 part within 1×10^57 parts.
Which seems like an insane coincidence. The development of inflation, however, solves this, by expanding the Universe an incomprehensible amount moments after the Big Bang. Pre and post inflation Universes can have vastly different levels of curvature.
In the olden days, cosmologists used to say that the flatness of the Universe had implications for its future. If the Universe was curved where you could complete a full journey with less than 4 turns, that meant it was closed and destined to collapse in on itself.
And it was more than 4 turns, it was open and destined to expand forever.
New results from NASA’s Galaxy Evolution Explorer and the Anglo-Australian Telescope atop Siding Spring Mountain in Australia confirm that dark energy (represented by purple grid) is a smooth, uniform force that now dominates over the effects of gravity (green grid). Image credit: NASA/JPL-Caltech
Well, that doesn’t really matter any more. In 1998, the astronomers discovered dark energy, which is this mysterious force accelerating the expansion of the Universe. Whether the Universe is open, closed or flat, it’s going to keep on expanding. In fact, that expansion is going to accelerate, forever.
I hope this gives you a little more understanding of what cosmologists mean when they say that the Universe is flat. And how do we know it’s flat? Very precise measurements in the Cosmic Microwave Background Radiation.
Is there anything that all pervasive relic of the early Universe can’t do?
The Big Bang. The discovery that the Universe has been expanding for billions of years is one of the biggest revelations in the history of science. In a single moment, the entire Universe popped into existence, and has been expanding ever since.
We know this because of multiple lines of evidence: the cosmic microwave background radiation, the ratio of elements in the Universe, etc. But the most compelling one is just the simple fact that everything is expanding away from everything else. Which means, that if you run the clock backwards, the Universe was once an extremely hot dense region
A billion years after the big bang, hydrogen atoms were mysteriously torn apart into a soup of ions. Credit: NASA/ESA/A. Felid (STScI)).
Let’s go backwards in time, billions of years. The closer you get to the Big Bang, the closer everything was, and the hotter it was. When you reach about 380,000 years after the Big Bang, the entire Universe was so hot that all matter was ionized, with atomic nuclei and electrons buzzing around each other.
Keep going backwards, and the entire Universe was the temperature and density of a star, which fused together the primordial helium and other elements that we see to this day.
Continue to the beginning of time, and there was a point where everything was so hot that atoms themselves couldn’t hold together, breaking into their constituent protons and neutrons. Further back still and even atoms break apart into quarks. And before that, it’s just a big question mark. An infinitely dense Universe cosmologists called the singularity.
When you look out into the Universe in all directions, you see the cosmic microwave background radiation. That’s that point when the Universe cooled down so that light could travel freely through space.
And the temperature of this radiation is almost exactly the same in all directions that you look. There are tiny tiny variations, detectable only by the most sensitive instruments.
Cosmic microwave background seen by Planck. Credit: ESA
When two things are the same temperature, like a spoon in your coffee, it means that those two things have had an opportunity to interact. The coffee transferred heat to the spoon, and now their temperatures have equalized.
When we see this in opposite sides of the Universe, that means that at some point, in the ancient past, those two regions were touching. That spot where the light left 13.8 billion years ago on your left, was once directly touching that spot on your right that also emitted its light 13.8 billion years ago.
This is a great theory, but there’s a problem: The Universe never had time for those opposite regions to touch. For the Universe to have the uniform temperature we see today, it would have needed to spend enough time mixing together. But it didn’t have enough time, in fact, the Universe didn’t have any time to exchange temperature.
Imagine you dipped that spoon into the coffee and then pulled it out moments later before the heat could transfer, and yet the coffee and spoon are exactly the same temperature. What’s going on?
Alan H. Guth. Credit: Betsy Devine (CC BY-SA 3.0)
To address this problem, the cosmologist Alan Guth proposed the idea of cosmic inflation in 1980. That moments after the Big Bang, the entire Universe expanded dramatically.
And by “moments”, I mean that the inflationary period started when the Universe was only 10^-36 seconds old, and ended when the Universe was 10^-32 seconds old.
And by “expanded dramatically”, I mean that it got 10^26 times larger. That’s a 1 followed by 26 zeroes.
Before inflation, the observable Universe was smaller than an atom. After inflation, it was about 0.88 millimeters. Today, those regions have been stretched 93 billion light-years apart.
This concept of inflation was further developed by cosmologists Andrei Linde, Paul Steinhardt, Andy Albrecht and others.
Inflation resolved some of the shortcomings of the Big Bang Theory.
The first is known as the flatness problem. The most sensitive satellites we have today measure the Universe as flat. Not like a piece-of-paper-flat, but flat in the sense that parallel lines will remain parallel forever as they travel through the Universe. Under the original Big Bang cosmology, you would expect the curvature of the Universe to grow with time.
The horizon problem in Big Bang cosmology. How is it that distant parts of the universe possess such similar physical properties? Credit: Addison Wesley.
The second is the horizon problem. And this is the problem I mentioned above, that two regions of the Universe shouldn’t have been able to see each other and interact long enough to be the same temperature.
The third is the monopole problem. According to the original Big Bang theory, there should be a vast number of heavy, stable “monopoles”, or a magnetic particle with only a single pole. Inflation diluted the number of monopoles in the Universe so don’t detect them today.
Although the cosmic microwave background radiation appears mostly even across the sky, there could still be evidence of that inflationary period baked into it.
The Big Bang and primordial gravitational waves. Credit: bicepkeck.org
In order to do this, astronomers have been focusing on searching for primordial gravitational waves. These are different from the gravitational waves generated through the collision of massive objects. Primordial gravitational waves are the echoes from that inflationary period which should be theoretically detectable through the polarization, or orientation, of light in the cosmic microwave background radiation.
A collaboration of scientists used an instrument known as the Background Imaging of Cosmic Extragalactic Polarization (or BICEP2) to search for this polarization, and in 2014, they announced that maybe, just maybe, they had detected it, proving the theory of cosmic inflation was correct.
Unfortunately, another team working with the space-based Planck telescope posted evidence that the fluctuations they saw could be fully explained by intervening dust in the Milky Way.
Planck’s view of its nine frequencies. Credit: ESA and the Planck Collaboration
The problem is that BICEP2 and Planck are designed to search for different frequencies. In order to really get to the bottom of this question, more searches need to be done, scanning a series of overlapping frequencies. And that’s in the works now.
BICEP2 and Planck and the newly developed South Pole Telescope as well as some observatories in Chile are all scanning the skies at different frequencies at the same time. Distortion from various types of foreground objects, like dust or radiation should be brighter or dimmer in the different frequencies, while the light from the cosmic microwave background radiation should remain constant throughout.
There are more telescopes, searching more wavelengths of light, searching more of the sky. We could know the answer to this question with more certainty shortly.
One of the most interesting implications of cosmic inflation, if proven, is that our Universe is actually just one in a vast multiverse. While the Universe was undergoing that dramatic expansion, it could have created bubbles of spacetime that spawned other universes, with different laws of physics.
Artist concept of the multiverse. Credit: Florida State University
In fact, the father of inflation, Alan Guth, said, “It’s hard to build models of inflation that don’t lead to a multiverse.”
And so, if inflation does eventually get confirmed, then we’ll have a whole multiverse to search for in the cosmic microwave background radiation.
The Big Bang was one of the greatest theories in the history of science. Although it did have a few problems, cosmic inflation was developed to address them. Although there have been a few false starts, astronomers are now performing a sensitive enough search that they might find evidence of this amazing inflationary period. And then it’ll be Nobel Prizes all around.
A typical LHCb event fully reconstructed. Particles identified as pions, kaon, etc. are shown in different colours. Credit: LHCb collaboration
Since it began its second operational run in 2015, the Large Hadron Collider has been doing some pretty interesting things. For example, starting in 2016, researchers at CERN began using the collide to conduct the Large Hadron Collider beauty experiment (LHCb). This is investigation seeks to determine what it is that took place after the Big Bang so that matter was able to survive and create the Universe that we know today.
According to the research paper, which appeared in arXiv on March 14th, 2017, the particles that were detected were excited states of what is known as a “Omega-c-zero” baryon. Like other particles of its kind, the Omega-c-zero is made up of three quarks – two of which are “strange” while the third is a “charm” quark. The existence of this baryon was confirmed in 1994. Since then, researchers at CERN have sought to determine if there were heavier versions.
The LHCb collaboration team. Credit: lhcb-public.web.cern.ch
And now, thanks to the LHCb experiment, it appears that they have found them. The key was to examine the trajectories and the energy left in the detector by particles in their final configuration and trace them back to their original state. Basically, Omega-c-zero particles decay via the strong force into another type of baryon (Xi-c-plus) and then via the weak force into protons, kaons, and pions.
From this, the researchers were able to determine that what they were seeing were Omega-c-zero particles at different energy states (i.e. of different sizes and masses). Expressed in megaelectronvolts (MeV), these particles have masses of 3000, 3050, 3066, 3090 and 3119 MeV, respectively. This discovery was rather unique, since it involved the detection of five higher energy states of a particle at the same time.
This was made possible thanks to the specialized capabilities of the LHCb detector and the large dataset that was accumulated from the first and second runs of the LHC – which ran from 2009 to 2013, and since 2015, respectively. Armed with the right equipment and experience, the researchers were able to identify the particles with an overwhelming level of certainty, ruling out the possibility that it was a statistical fluke in the data.
The discovery is also expected to shed light on some of the deeper mysteries of subatomic particles, like how the three constituent quarks are bound inside a baryon by the “strong force” – i.e. the fundamental force that is responsible for holding the insides of atoms together. Another mystery that this could help resolve in the correlation between different quark states.
The Large Hadron Collider is the world’s largest and most powerful particle accelerator Credit: CERN
As Dr Greig Cowan – a researcher from the University of Edinburgh who works on the LHCb experiment at Cern’s LHC – explained in an interview with the BBC:
“This is a striking discovery that will shed light on how quarks bind together. It may have implications not only to better understand protons and neutrons, but also more exotic multi-quark states, such as pentaquarks and tetraquarks.“
The next step will be to determine the quantum numbers of these new particles (the numbers used to identify the properties of a specific particle) as well as determining their theoretical significance. Since it came online, the LHC has been helping to confirm the Standard Model of particle physics, as well as reaching beyond it to explore the greater unknowns of how the Universe came to be, and how the fundamental forces that govern it fit together.
In the end, the discovery of these five new particles could be a crucial step along the road towards a Theory of Everything (ToE), or just another piece in the very big puzzle that is our existence. Stay tuned to see which!
This illustration shows the evolution of the Universe, from the Big Bang on the left, to modern times on the right. Image: NASA
Over the past decades, scientists have wrestled with a problem involving the Big Bang Theory. The Big Bang Theory suggests that there should be three times as much lithium as we can observe. Why is there such a discrepancy between prediction and observation?
To get into that problem, let’s back up a bit.
The Big Bang Theory (BBT) is well-supported by multiple lines of evidence and theory. It’s widely accepted as the explanation for how the Universe started. Three key pieces of evidence support the BBT:
rough agreement between calculations and observations of the abundance of primordial light nuclei (Do NOT attempt to say this three times in rapid succession!)
But the BBT still has some niggling questions.
The missing lithium problem is centred around the earliest stages of the Universe: from about 10 seconds to 20 minutes after the Big Bang. The Universe was super hot and it was expanding rapidly. This was the beginning of what’s called the Photon Epoch.
At that time, atomic nuclei formed through nucleosynthesis. But the extreme heat that dominated the Universe prevented the nuclei from combining with electrons to form atoms. The Universe was a plasma of nuclei, electrons, and photons.
Only the lightest nuclei were formed during this time, including most of the helium in the Universe, and small amounts of other light nuclides, like deuterium and our friend lithium. For the most part, heavier elements weren’t formed until stars appeared, and took on the role of nucleosynthesis.
The problem is that our understanding of the Big Bang tells us that there should be three times as much lithium as there is. The BBT gets it right when it comes to other primordial nuclei. Our observations of primordial helium and deuterium match the BBT’s predictions. So far, scientists haven’t been able to resolve this inconsistency.
But a new paper from researchers in China may have solved the puzzle.
One assumption in Big Bang nucleosynthesis is that all of the nuclei are in thermodynamic equilibrium, and that their velocities conform to what’s called the classical Maxwell-Boltzmann distribution. But the Maxwell-Boltzmann describes what happens in what is called an ideal gas. Real gases can behave differently, and this is what the researchers propose: that nuclei in the plasma of the early photon period of the Universe behaved slightly differently than thought.
This graphics shows the distribution of early primordial light elements in the Universe by time and temperature. Temperature along the top, time along the bottom, and abundance on the side. Image: Hou et al. 2017
The authors applied what is known as non-extensive statistics to solve the problem. In the graph above, the dotted lines of the author’s model predict a lower abundance of the beryllium isotope. This is key, since beryllium decays into lithium. Also key is that the resulting amount of lithium, and of the other lighter nuclei, now all conform to the amounts predicted by the Maxwell-Boltzmann distribution. It’s a eureka moment for cosmology aficionados.
The decay chains of primordial light nuclei in the early days of the Universe. Notice the thin red arrows between Beryllium and Lithium at 10-13, the earliest time shown on this chart. Image: Chou et. al.
What this all means is scientists can now accurately predict the abundance in the primordial universe of the three primordial nuclei: helium, deuterium, and lithium. Without any discrepancy, and without any missing lithium.
This is how science grinds away at problems, and if the authors of the paper are correct, then it further validates the Big Bang Theory, and brings us one step closer to understanding how our Universe was formed.
Special Guest:
Samuel Mason is the Director of the Tesla Science Foundation, NJ Chapter. The mission of the Tesla Science Foundation is to establish and promote the recognition and awareness of Nikola Tesla’s inventions, patents, theories, philosophies, lectures, and innovations. Guests:
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The primary mirror of the James Webb Space Telescope, in all its gleaming glory! Image: NASA/Chris Gunn
NASA has some high hopes for the James Webb Space Telescope, which finished the “cold” phase of its construction at the end of November 2016. The result of 20 years of engineering and construction, this telescope is seen as Hubble’s natural successor. Once it is deployed in October of 2018, it will use a 6.5 meter (21 ft 4 in) primary mirror to examine the Universe in the visible, near-infrared, and mid-infrared wavelengths.
All told, the JWST will be 100 times more powerful than its predecessor and will be capable of looking over 13 billion years in time. To honor the completion of the telescope, Northrop Grumman – the company contracted by NASA to build it – and Crazy Boat Pictures teamed up to produce a short film about it. Titled “Into the Unknown – the Story of NASA’s James Webb Space Telescope“, the video chronicles the project from inception to completion.
The film (which you can watch at the bottom of the page) shows the construction of the telescope’s large mirrors, its instrument package, and its framework. It also features conversations with the scientists and engineers who were involved and some stunning visuals. In addition to detailing the creation process, the film also delves into the telescope’s mission and all the cosmological questions it will address.
In addressing the nature of James Webb’s mission, the film also pays homage to the Hubble Space Telescope and its many accomplishments. Over the course of its 26 years of operation, it has revealed auroras and supernovas and discovered billions of stars, galaxies, and exoplanets, some of which were shown to orbit within their star’s respective habitable zones.
On top of that, Hubble was used to determine the age of the Universe (13.8 billion years) and confirmed the existence of the supermassive black hole (SMBH) – Sagittarius A* – at the center of our galaxy, not to mention many others. It was also responsible for measuring the rate at which the Universe is expanding – in other words, measuring the Hubble Constant.
This played a pivotal role in helping scientists to develop the theory of Dark Energy, one of the most profound discoveries since Edwin Hubble (the telescope’s namesake) proposed that the Universe is in a state of expansion back in 1929. So it goes without saying that the deployment of the Hubble Space Telescope led to some of the greatest discoveries in modern astronomy.
That being said, Hubble is still subject to limitations, which astronomers are now hoping to push past. For one, its instruments are not able to pick up the most distant (and hence, dimmest) galaxies in the Universe, which date to just a few hundred million years after the Big Bang. Even with “The Deep Fields” initiative, Hubble is still limited to seeing back to about half a billion years after the Big Bang.
Illustration of the depth by which Hubble imaged galaxies in prior Deep Field initiatives in units of the Age of the Universe. Credit: NASA and A. Feild (STScI)
As Dr. John Mather, the project scientist for the James Webb Telescope, told Universe Today via email:
“Hubble showed us that we could not see the first galaxies being born, because they’re too far away, too faint, and too red. JWST is bigger, colder, and observes infrared light to see those first galaxies. Hubble showed us there’s a black hole in the center of almost every galaxy. JWST will look as far back in time as possible to see when and how that happened: did the galaxy form the black hole, or did the galaxy grow around a pre-existing black hole? Hubble showed us great clouds of glowing gas and dust where stars are being born. JWST will look through the dust clouds to see the stars themselves as they form in the cloud. Hubble showed us that we can see some planets around other stars, and that we can get chemical information about other planets that happen to pass directly in front of their stars. JWST will extend this to longer wavelengths with a bigger telescope, with a possibility of detecting water on a super-Earth exoplanet. Hubble showed us details of planets and asteroids close to home, and JWST will give a closer look, though it’s still better to send a visiting robot if we can.”
Basically, the JWST will be able to see farther back to about 100 million years after the Big Bang, when the first stars and galaxies were born. It is also designed to operate at the L2 Lagrange Point, farther away from the Earth than Hubble – which was designed to remain in low-Earth orbit. This means the JWST will be subject to less thermal and optical interference from the Earth and the Moon, but will also make it more difficult to service.
With its much larger set of segmented mirrors, it will observe the Universe as it captures light from the first galaxies and stars. Its extremely-sensitive suite of optics will also be able to gather information in the long-wavelength (orange-red) and infrared wavelengths with greater accuracy, measuring the redshift of distant galaxies and even helping in the hunt for extra-solar planets.
A primary mirror segments of the James Webb Space Telescope, made of beryllium. Credit: NASA/MSFC/David Higginbotham/Emmett Given
With the assembly of its major components now complete, the telescope will spend the next two years undergoing tests before its scheduled launch date in October 2018. These will include stress tests that will subject the telescope to the types of intense vibrations, sounds, and g forces (ten times Earth’s gravity) it will experience inside the Ariane 5 rocket that will take it into space.
Six months before its deployment, NASA also plans to send the JWST to the Johnson Space Center, where it will be subjected to the kinds of conditions it will experience in space. This will consist of scientists placing the telescope in a chamber where temperatures will be lowered to 53 K (-220 °C; -370 °F), which will simulate its operating conditions at the L2 Lagrange Point.
Once all of that is complete, and the JWST checks out, it will be launched aboard an Ariane 5 rocket from Arianespace’s ELA-3 launch pad in French Guayana. And thanks to experience gained from Hubble and updated algorithms, the telescope will be focused and gathering information shortly after it is launched. And as Dr. Mather explained, the big cosmological questions it is expected to address are numerous:
“Where did we come from? The Big Bang gave us hydrogen and helium spread out almost uniformly across the universe. But something, presumably gravity, stopped the expansion of the material and turned it into galaxies and stars and black holes. JWST will look at all these processes: how did the first luminous objects form, and what were they? How and where did the black holes form, and what did they do to the growing galaxies? How did the galaxies cluster together, and how did galaxies like the Milky Way grow and develop their beautiful spiral structure? Where is the cosmic dark matter and how does it affect ordinary matter? How much dark energy is there, and how does it change with time?”
Needless to say, NASA and the astronomical community are quite excited that the James Webb Telescope is finished construction, and can’t wait until it is deployed and begins to send back data. One can only imagine the kinds of things it will see deep in the cosmic field. But in the meantime, be sure to check out the film and see how this effort all came together:
Today, CERN announced that the LHCb experiment had revealed the existence of two new baryon subatomic particles. Credit: CERN/LHC/GridPP
What if it were possible to observe the fundamental building blocks upon which the Universe is based? Not a problem! All you would need is a massive particle accelerator, an underground facility large enough to cross a border between two countries, and the ability to accelerate particles to the point where they annihilate each other – releasing energy and mass which you could then observe with a series of special monitors.
Well, as luck would have it, such a facility already exists, and is known as the CERN Large Hardron Collider (LHC), also known as the CERN Particle Accelerator. Measuring roughly 27 kilometers in circumference and located deep beneath the surface near Geneva, Switzerland, it is the largest particle accelerator in the world. And since CERN flipped the switch, the LHC has shed some serious light on some deeper mysteries of the Universe.
Purpose:
Colliders, by definition, are a type of a particle accelerator that rely on two directed beams of particles. Particles are accelerated in these instruments to very high kinetic energies and then made to collide with each other. The byproducts of these collisions are then analyzed by scientists in order ascertain the structure of the subatomic world and the laws which govern it.
The Large Hadron Collider is the most powerful particle accelerator in the world. Credit: CERN
The purpose of colliders is to simulate the kind of high-energy collisions to produce particle byproducts that would otherwise not exist in nature. What’s more, these sorts of particle byproducts decay after very short period of time, and are are therefor difficult or near-impossible to study under normal conditions.
The term hadron refers to composite particles composed of quarks that are held together by the strong nuclear force, one of the four forces governing particle interaction (the others being weak nuclear force, electromagnetism and gravity). The best-known hadrons are baryons – protons and neutrons – but also include mesons and unstable particles composed of one quark and one antiquark.
Design:
The LHC operates by accelerating two beams of “hadrons” – either protons or lead ions – in opposite directions around its circular apparatus. The hadrons then collide after they’ve achieved very high levels of energy, and the resulting particles are analyzed and studied. It is the largest high-energy accelerator in the world, measuring 27 km (17 mi) in circumference and at a depth of 50 to 175 m (164 to 574 ft).
The tunnel which houses the collider is 3.8-meters (12 ft) wide, and was previously used to house the Large Electron-Positron Collider (which operated between 1989 and 2000). This tunnel contains two adjacent parallel beamlines that intersect at four points, each containing a beam that travels in opposite directions around the ring. The beam is controlled by 1,232 dipole magnets while 392 quadrupole magnets are used to keep the beams focused.
Superconducting quadrupole electromagnets are used to direct the beams to four intersection points, where interactions between accelerated protons will take place.Credit: Wikipedia Commons/gamsiz
About 10,000 superconducting magnets are used in total, which are kept at an operational temperature of -271.25 °C (-456.25 °F) – which is just shy of absolute zero – by approximately 96 tonnes of liquid helium-4. This also makes the LHC the largest cryogenic facility in the world.
When conducting proton collisions, the process begins with the linear particle accelerator (LINAC 2). After the LINAC 2 increases the energy of the protons, these particles are then injected into the Proton Synchrotron Booster (PSB), which accelerates them to high speeds.
They are then injected into the Proton Synchrotron (PS), and then onto the Super Proton Synchrtron (SPS), where they are sped up even further before being injected into the main accelerator. Once there, the proton bunches are accumulated and accelerated to their peak energy over a period of 20 minutes. Last, they are circulated for a period of 5 to 24 hours, during which time collisions occur at the four intersection points.
During shorter running periods, heavy-ion collisions (typically lead ions) are included the program. The lead ions are first accelerated by the linear accelerator LINAC 3, and the Low Energy Ion Ring (LEIR) is used as an ion storage and cooler unit. The ions are then further accelerated by the PS and SPS before being injected into LHC ring.
While protons and lead ions are being collided, seven detectors are used to scan for their byproducts. These include the A Toroidal LHC ApparatuS (ATLAS) experiment and the Compact Muon Solenoid (CMS), which are both general purpose detectors designed to see many different types of subatomic particles.
Then there are the more specific A Large Ion Collider Experiment (ALICE) and Large Hadron Collider beauty (LHCb) detectors. Whereas ALICE is a heavy-ion detector that studies strongly-interacting matter at extreme energy densities, the LHCb records the decay of particles and attempts to filter b and anti-b quarks from the products of their decay.
CERN, which stands for Conseil Européen pour la Recherche Nucléaire (or European Council for Nuclear Research in English) was established on Sept 29th, 1954, by twelve western European signatory nations. The council’s main purpose was to oversee the creation of a particle physics laboratory in Geneva where nuclear studies would be conducted.
Illustration showing the byproducts of lead ion collisions, as monitored by the ATLAS detector. Credit: CERN
Soon after its creation, the laboratory went beyond this and began conducting high-energy physics research as well. It has also grown to include twenty European member states: France, Switzerland, Germany, Belgium, the Netherlands, Denmark, Norway, Sweden, Finland, Spain, Portugal, Greece, Italy, the UK, Poland, Hungary, the Czech Republic, Slovakia, Bulgaria and Israel.
Construction of the LHC was approved in 1995 and was initially intended to be completed by 2005. However, cost overruns, budget cuts, and various engineering difficulties pushed the completion date to April of 2007. The LHC first went online on September 10th, 2008, but initial testing was delayed for 14 months following an accident that caused extensive damage to many of the collider’s key components (such as the superconducting magnets).
On November 20th, 2009, the LHC was brought back online and its First Run ran from 2010 to 2013. During this run, it collided two opposing particle beams of protons and lead nuclei at energies of 4 teraelectronvolts (4 TeV) and 2.76 TeV per nucleon, respectively. The main purpose of the LHC is to recreate conditions just after the Big Bang when collisions between high-energy particles was taking place.
Major Discoveries:
During its First Run, the LHCs discoveries included a particle thought to be the long sought-after Higgs Boson, which was announced on July 4th, 2012. This particle, which gives other particles mass, is a key part of the Standard Model of physics. Due to its high mass and elusive nature, the existence of this particle was based solely in theory and had never been previously observed.
The discovery of the Higgs Boson and the ongoing operation of the LHC has also allowed researchers to investigate physics beyond the Standard Model. This has included tests concerning supersymmetry theory. The results show that certain types of particle decay are less common than some forms of supersymmetry predict, but could still match the predictions of other versions of supersymmetry theory.
In May of 2011, it was reported that quark–gluon plasma (theoretically, the densest matter besides black holes) had been created in the LHC. On November 19th, 2014, the LHCb experiment announced the discovery of two new heavy subatomic particles, both of which were baryons composed of one bottom, one down, and one strange quark. The LHCb collaboration also observed multiple exotic hadrons during the first run, possibly pentaquarks or tetraquarks.
Since 2015, the LHC has been conducting its Second Run. In that time, it has been dedicated to confirming the detection of the Higgs Boson, and making further investigations into supersymmetry theory and the existence of exotic particles at higher-energy levels.
The ATLAS detector, one of two general-purpose detectors at the Large Hadron Collider (LHC). Credit: CERN
In the coming years, the LHC is scheduled for a series of upgrades to ensure that it does not suffer from diminished returns. In 2017-18, the LHC is scheduled to undergo an upgrade that will increase its collision energy to 14 TeV. In addition, after 2022, the ATLAS detector is to receive an upgrade designed to increase the likelihood of it detecting rare processes, known as the High Luminosity LHC.
The collaborative research effort known as the LHC Accelerator Research Program (LARP) is currently conducting research into how to upgrade the LHC further. Foremost among these are increases in the beam current and the modification of the two high-luminosity interaction regions, and the ATLAS and CMS detectors.
Who knows what the LHC will discover between now and the day when they finally turn the power off? With luck, it will shed more light on the deeper mysteries of the Universe, which could include the deep structure of space and time, the intersection of quantum mechanics and general relativity, the relationship between matter and antimatter, and the existence of “Dark Matter”.
Super-Kamiokande, a neutrino detector in Japan, holds 50,000 tons of ultrapure water surrounded by light tubes. Credit: Super-Kamiokande Observatory
Under Mount Ikeno, Japan, in an old mine that sits one-thousand meters (3,300 feet) beneath the surface, lies the Super-Kamiokande Observatory (SKO). Since 1996, when it began conducting observations, researchers have been using this facility’s Cherenkov detector to look for signs of proton decay and neutrinos in our galaxy. This is no easy task, since neutrinos are very difficult to detect.
But thanks to a new computer system that will be able to monitor neutrinos in real-time, the researchers at the SKO will be able to research these mysteries particles more closely in the near future. In so doing, they hope to understand how stars form and eventually collapse into black holes, and sneak a peak at how matter was created in the early Universe.
Neutrinos, put simply, are one of the fundamental particles that make up the Universe. Compared to other fundamental particles, they have very little mass, no charge, and only interact with other types of particles via the weak nuclear force and gravity. They are created in a number of ways, most notably through radioactive decay, the nuclear reactions that power a star, and in supernovae.
Timeline of the Big Bang, which unleashed cosmic neutrinos that can still be detected today. Credit: NASA / JPL-Caltech / A. Kashlinsky (GSFC).
In accordance with the standard Big Bang model, the neutrinos left over from the creation of the Universe are the most abundant particles in existence. At any given moment, trillions of these particles are believed to be moving around us and through us. But because of the way they interact with matter (i.e. only weakly) they are extremely difficult to detect.
For this reason, neutrino observatories are built deep underground to avoid interference from cosmic rays. They also rely on Cherenkov detectors, which are essentially massive water tanks that have thousands of sensors lining their walls. These attempt to detect particles as they are slowed down to the local speed of light (i.e. the speed of light in water), which is made evident by the presence of a glow – known as Cherenkov radiation.
The detector at the SKO is currently the largest in the world. It consists of a cylindrical stainless steel tank that is 41.4 m (136 ft) tall and 39.3 m (129 ft) in diameter, and holds over 45,000 metric tons (50,000 US tons) of ultra-pure water. In the interior, 11,146 photomultiplier tubes are mounted, which detect light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum with extreme sensitivity.
For years, researchers at the SKO have used the facility to examine solar neutrinos, atmospheric neutrinos and man-made neutrinos. However, those that are created by supernovas are very difficult to detect, since they appear suddenly and difficult to distinguish from other kinds. However, with the newly-added computer system, the Super Komiokande researchers are hoping that will change.
Cherenkov radiation glowing in the core of the Advanced Test Reactor at the Idaho National Laboratory Credit: Wikipedia Commons/Argonne National Laboratory
“Supernova explosions are one of the most energetic phenomena in the universe and most of this energy is released in the form of neutrinos. This is why detecting and analyzing neutrinos emitted in these cases, other than those from the Sun or other sources, is very important for understanding the mechanisms in the formation of neutron stars –a type of stellar remnant– and black holes”.
Basically, the new computer system is designed to analyze the events recorded in the depths of the observatory in real-time. If it detects an abnormally large flows of neutrinos, it will quickly alert the experts manning the controls. They will then be able to assess the significance of the signal within minutes and see if it is actually coming from a nearby supernova.
“During supernova explosions an enormous number of neutrinos is generated in an extremely small space of time – a few seconds – and this why we need to be ready,” Labarga added. “This allows us to research the fundamental properties of these fascinating particles, such as their interactions, their hierarchy and the absolute value of their mass, their half-life, and surely other properties that we still cannot even imagine.”
The Super-Kamiokande experiment is located at the Kamioka Observatory, 1,000 m below ground in a mine near the Japanese city of Kamioka. Credit: Kamioka Observatory/ICRR/University of Toky
Equally as important is the fact this system will give the SKO the ability to issue early warnings to research centers around the world. Ground-based observatories, where astronomers are keen to watch the creation of cosmic neutrinos by supernova, will then be able to point all of their optical instruments towards the source in advance (since the electromagnetic signal will take longer to arrive).
Through this collaborative effort, astrophysicists may be able to better understand some of the most elusive neutrinos of all. Discerning how these fundamental particles interact with others could bring us one step closer to a Grand Unified Theory – one of the major goals of the Super-Kamiokande Observatory.
To date, only a few neutrino detectors exist in the world. These include the Irvine-Michigan-Brookhaven (IMB) detector in Ohio, the Subdury Neutrino Observatory (SNOLAB) in Ontario, Canada, and the Super Kamiokande Observatory in Japan.
