The threat of nuclear war and the increasing rate of climate change means we must walk a thin line when it comes to nuclear power.
When you are told what someone is against, ask them what they are for. If you against nuclear power, what kind of power are you for? Reasonable answers include coal, natural gas, biomass, wind, solar, hydro, or geothermal. However, not all of these answers are equally genuine given the constraints of our world. Renewable energy sources have not historically been economically or technologically viable. Our energy landscape is changing today. A future with more renewables and no nuclear power is possible, yet it may not be the best choice if we are serious about climate change. Nuclear power has often been eschewed out of fear, not practicality or rationality.
Imagine the closest star beyond the Sun has a planet orbiting it about the size of Earth. Visualize what your sunset would look like on this distant planet. Perhaps there would be two stars at the center of this solar system. Your sunset would be breathtaking. You could even visualize what the Sun would look like from this planet – just another unassuming star in the sky. You don't have to merely imagine that such a planet might exist. A planet like this really does exist – of course you'd still have to imagine the part where you are on the surface of this world. The Alpha Centauri star system, which is essentially a triple star system of Alpha Centauri A, Alpha Centauri B, and Proxima Centauri has just such a planet. There is a planet in the sky waiting for us at a distance that is just two hundred and seventy thousand times further than the Earth is from the Sun. This planet is near 1500 degrees on the surface, so we wouldn't want to be there, but nonetheless the fact is that astronomers are finding similar planets commonly. There may be a planet just the size of Earth at a nice temperature quite near us galactic speaking. We are searching.
Most planets don't seem to be much like Earth. In fact so far we haven't found a single planet that has a temperature and size similar to Earth, but part of the problem with finding planets is that finding big giant planets – like Jupiter is easy – while small rocky planets like Earth are elusive. But we are on the edge of discovery. All in all Earth-like planets likely abound. In fact with 95% confidence there is an Earth size planet in the habitable zone of a small star within 23 light years of us. The habitable zone is the place where a planet would not be too hot or too cold. A place where a planet wouldn't see its oceans boiled off or frozen into desolate ice tundra. Habitable planets are common in our galaxy and by galactic standards not very far apart. On average Earth-like planets are only 13 light-years apart.
The research group I work with has made a fantastic poster about how galaxies form in the cosmic web and how we use computer simulations to understand such a complex process. We made the poster as a form of outreach and in particular for students who may be interested in astronomy research. Please feel free share or print the poster and if there is interest we may consider printing and sending out full size version of the poster for public display. Here is a large pdf version of the poster "Galaxy formation in the Cosmic Web".
See a bit more over at Common Observer...
Comets have long been portents of change. They challenge the rote repetition of our skies. An astute observer of the sky will perhaps have recently noticed a new object in the sky, a comet, present for the last few weeks (you would have had to look east just before sunrise near the star Spica). This was the comet ISON. But comet ISON, having strayed too close to the Sun, has been mostly annihilated. If there is a comet in the sky and no one sees it, was it ever really there?
William Carlos William's poem, Landscape with the Fall of Icarus, captures the essence of comet ISON's elusive journey around the Sun. Brueghel, the Felmish Renaissance painter, carefully recorded the event like a faithful astronomer, but the worker is not keen on the sky and Icarus goes wholly unnoticed. It is just the same to the worker, for had they noticed Icarus or not it would likely make no difference to their toils in the field. And similarly ISON went largely unnoticed.
According to Brueghel
when Icarus fell
it was spring
a farmer was ploughing
his field
the whole pageantry
of the year was
awake tingling
with itself
sweating in the sun
that melted
the wings' wax
unsignificantly
off the coast
there was
a splash quite unnoticed
this was
Icarus drowning
ISON made a brief appearance to the unaided eye for a few days before it grazed the sun and then uncoiled itself. But to the learned astronomer ISON is still interesting. Comets are rare objects in the inner solar system so even a dead comet is a chance to learn something, in fact, further spectroscopic observations of this dead comet's remains will continue to tell us exactly what it was made of. There is a legacy here.
There is a new object in the sky. Comet ISON is an icy wanderer making its first and probably last last trip into the solar system from its previous home in the Oort cloud. It will graze by the Sun brilliantly and then depart. As it approaches the inner solar system, it is now inside the orbit of Earth, astronomers have been watching its outbursts of ice and volatile materials which then reflect sunlight and make the comet very bright. It is just visible to the naked eye according to some reports now. Comet ISON has increased in brightness many times over in the last few days.
We don't know how bright it will get. Astronomers generally just don't know as much about comets as we would like. The comet has undergone outbursts of brightening and dimming, while generally tending to get brighter as it enters in to the inner solar system ISON may become entirely disrupted or get brighter and brighter - the comet of the century. The reason for all this uncertainty is that comets and this object in particular are not well studied. But also it is that comets are not dense rocks, but rather they are loose aggregations of dust, rubble, and ices. Tidal forces and heating of the ices can literally unbind entire comets. I haven't been able to see it for myself yet, it hasn't been quite visible because it rises so late I think. Currently, if you want to see comet ISON from North America look east right before dawn as it passes Mercury.
Read the rest of my post on comet ISON over at Common Observer...
I have a new online project and venue that I have launched! Common Observer is a collaborative online venue of science, art, philosophy, and culture. The tagline is "Common Observer, uncommon observations." The idea is that we must reason as if we are the most common observer, but that doesn't preclude uncommon observations. An uncommon observation is something that challenges our human condition of common observation. A poem, a theorem, a dance, an equation, a painting, a story, a novel, or a theoretical truth may all be uncommon observations about the world we inhabit.
Yet fear not, I will still post on The Astronomist, in particular I will cross post any original scientific content I create. The reason for this shift of focus is at least two fold. First, it is hard to find time to generate original thoughtful content while finishing a PhD so Common Observer will have more aggregated content. Second, while so many people love astronomy, I feel a broader forum of wider interests will better grip reader's attention, as well as my own attention.
I hope that Common Observer can be a successful collaborative project. In order to realize that goal I am currently searching for culture, art, philosophy, or poetry contributors. So please check out the new project, share it with friends and colleagues, or contact me if you have inclinations to collaborate. Follow Common Observer on twitter, subscribe to the RSS, or just visit the site often. Thanks for the continued support.
Dark matter is the commonest, most elusive stuff in the universe. Can we grasp this great unsolved problem in physics?
The world we see is an illusion, albeit a highly persistent one. We have gradually got used to the idea that nature’s true reality is one of uncertain quantum fields; that what we see is not necessarily what is. Dark matter is a profound extension of this concept. It appears that the majority of matter in the universe has been hidden from us. That puts physicists and the general public alike in an uneasy place. Physicists worry that they can’t point to an unequivocal confirmed prediction or a positive detection of the stuff itself. The wider audience finds it hard to accept something that is necessarily so shadowy and elusive.
ALMA (the Atacama Large Millimeter/submillimeter Array) is the most complex and ambitious astronomical observatory ever completed. And it is officially completed. Last week the telescope array was inaugurated at an official ceremony; all the major systems of the telescope are now operational. ALMA is an important instrument for astronomers because it allows us to see in the submillimeter wavelength band where stars formation in distant galaxies are evident. In addition to seeing distant galaxies dusty obscured regions of space can be explored with this instrument. In order to get such a fantastic view of the universe astronomers have had to build the telescope array at an elevation of 5000 meters (16,400 feet) in the dry Atacama desert because the atmosphere would otherwise (particularly water vapor) block the light at the these wavelengths. There have been many engineering and management hurdles in the completion of ALMA so the success of the project deserves recognition. ALMA is an expensive partnership between Chile, Europe, North America, and East Asia that represents what is hopefully the beginning of many more massive multinational collaborative astronomical observatories. The European Southern Observatory who does a lot of the primary management of the observatory also does a lot of great work generating public outreach. They have produced this video which presents the history of ALMA from the origins of the project decades ago to the recent first science results.
Alma means soul in Spanish. A beautiful name for the observatory that looks so serene as it gazes up at the Milky Way discovering our cosmic origins.
Quantum computing so close or so far? The following promotional video is quite optimistic, but it does a decent job of explaining the most basic workings and potential of quantum computing so I thought I would share. For a more in depth perspective on the physics and prospects for quantum computers see my post about my visit to D-wave and their attempts to build the first quantum computer.
I just returned from the 30th Jerusalem Winter School in Theoretical Physics. It was an intensive school focusing on modern cosmology and galaxy formation with lectures from experts in the field. You can watch the lectures on online here and you can find the slides of the lectures here. In addition to just attending lectures in a boring conference room I of course got out and saw some sights in Israel like the old city of Jerusalem, the Dead Sea, and Masada. Since I was in the region I also struck out to Istanbul, Turkey. Istanbul is a place I have always wanted to see for the history, culture, and people. It was a long and winding trip and to sum it all up here are a few pictures.
A crescent moon over what I think is the Nuruosmaniye Mosque. The crescent moon is one the symbols of Turkey.
Alexander the Great as depicted on Alexander's Sarcophagus which is actually not his Sarcophagus but probably that of some governor of Sidon.
The Basilica Cistern is a 6th century Byzantine construction near the Hagia Sofia that held water for the city. It is quite eerie.
It is a long tradition to respect and live with animals in Istanbul. Beautiful cats and dogs wander throughout Istanbul. They are wild and may go where they want, but they are offered food and shelter so often stay near areas that are kind to them. It is kind of wonderful.
A shot from inside the Hagia Sofia taken during sunset.
Almost a decade ago when astronomers pointed the Hubble Space Telescope at an apparently featureless patch of the sky they were rewarded with a spectacular image. The was the Hubble Ultra Deep Field. The image allowed us to see that galaxies were forming as early as just a billion years after the Big Bang. The farther from Earth we look the farther back in time we see; starlight from those distant galaxies is just arriving at earth now. Now we have glimpsed even further with the Hubble Extreme Deep Field. This new image was created by aggregating 10 years of Hubble images taken centered at the same location of the original Ultra Deep Field. In addition to staking old images additional new images were included which had been taken with infrared cameras installed during the 2008 Hubble Space servicing missions. Infrared images offer important additional data for distant galaxies because the light from such distant objects has been stretched to longer wavelengths as it has journeyed across the universe. Here is the Hubble Extreme Deep Field:
This is the deepest image of the sky ever seen. It allows us to explore the faintest galaxies ever as far back as a time just half a billion years after the Big Bang. Soon though we will have even deeper images. The James Web Space Telescope will be a 6.5 meter diameter(or 21 foot, so big that it will be a segmented mirror that will unfold in space) space telescope that will launch in 2018. It will see further. Here is a simulated image of what the James Web Space Telescope will see:
If you are intrigued by Hubble's deep images of the sky there is a Google Event webinar to discuss the latest findings. The public is invited. show up online and ask questions of the astronomers involved. It is at 1 p.m. Sept. 27 and can be joined either at HubbleSite’s Google Plus page or the HubbleSite YouTube Channel.
I got asked about 2012 the other day. Something about Mayans predicting the end of the world and or hidden planetary alignments. Sometimes I don't know where to begin addressing something so wrong. Whether you ask a scientist or a Mayan elder though they agree there is no end of days in 2012. Here is a scientist, Neil deGrasse Tyson, on the subject:
And here is David Morrison, expert on Earth impact hazards, speaking about misconceptions related to the year 2012:
I met Don Winget years ago on a cloudy night in the control room of the Otto von Struve Telescope. His enthusiasm and excitement was overflowing. I could hardly see his face, lit eerily by red lights, but his words painted a picture of far away white dwarf stars. These stars are pulsating, cooling, and perhaps intertwined with mysterious undiscovered axion particles. He continues extraordinary pursuits. He is looking for white dwarfs on earth with the Z Machine. The Z Machine releases a powerful electrical discharge over a brief amount of time to create plasma, X-rays, shock waves, and an electromagnetic pulse. The Z Machine releases several times the combined energy output of all power plants on earth for a few brief nanoseconds with each shot. Usually it does nuclear weapons research, but this wonderful research aims to simulate aspects of white dwarf stars on earth and it is inspiring art.
Find a dark place on a late night this weekend to enjoy the Perseid meteor shower. You can even participate in citizen science by counting the number of meteors you see with NASA's Meteor Counter app.
LINDAU, Germany — Tommrrow CERN will make an announcement, likely about the Higgs boson. The Higgs boson is a key part of the standard model of physics and this is a rather exciting discovery. You can read my article about the prospects for the discovery of the Higgs boson over at the Nature Lindau blog where I am writing.
It may appear that I haven't been busy lately because of the death of posts here at The Astronomist. You would be right to suspect that in reality I have actually been extremely busy. I passed my general exam here at the University of Washington and I am now a proto-doctor or a PhD candidate as it were. Regardless, now that this hurtle is out of the way I just have to do a thesis. In the spare time I have been up to so many other things. I did an interview with WHAT which is an organization that aims to raise a discussion about philosophy, science, and culture. They are based out of Spain, but the idea is international and focuses on people. I was interviewed as part of their series sobre el futuro or about the future where I talked about the future of the universe and the future for humans on Earth. I really, like the quote they caught from me, "No creo que ningún astrónomo piense que estamos solos en el Universo." You can watch the interview here.
Next up I am traveling to Lindau Germany once again to cover the Lindau Nobel Laureate Conference. I will be writing with the Nature blog team. I am very excited to be returning to Lindau this year. I first covered the Lindau Nobel Laureate conference in 2010 and at the time I really didn't know what to expect. I found that Lindau is an amazing place where ideas are exchanged at a rapid pace and discussions of science and the future are pervasive. I love it. I will be attending the conference from the journalist perspective of course so I will be interviewing people, including Nobel Laureates, while at the same time learning and communicating what I discover to a larger audience. If you haven't heard of the Lindau conference before (or even if you have) I recommend checking out the Lindau Mediatheque where they have videos of the lectures given by the Laureates. I am already blogging over on the Lindau blog; the conference starts on July 1st and lasts an entire week. Please go check it out and I will talk to you again from Germany.
“From this distant vantage point, the Earth might not seem of particular interest. But for us, it’s different. Consider again that dot. That’s here, that’s home, that’s us. On it everyone you love, everyone you know, everyone you ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar,” every “supreme leader,” every saint and sinner in the history of our species lived there – on a mote of dust suspended in a sunbeam.”
The way of the future is fusion. I dream of a world where humans have harnessed the power of the Sun. Clean, safe, energy. But there is no clear path to fusion. The most exciting possibility for a future with fusion may be the International Thermonuclear Experimental Reactor or ITER. ITER is not the only option of course. Previously, I have discussed the National Ignition Facility or NIF which has pioneered unique technologies is the field, but their success is not ensured. Many small research projects around the world are also struggling to realize the dream of fusion, but with budget shortfalls and increasing pressure to produce results we as a society may shortsightedly end the dreams of a fusion future.
Fusion is what powers the Sun and all stars in our Universe. Fusion is the joining of two or more separate atomic nuclei into a larger nuclei. Fusion can create energy because the mass of the input and output nuclei are not necessarily equal in mass. An overview of what fusion is and why it is so important can be seen on my previous post on Fusion for the Future. Many scientists in the field acknowledge that a rapid development of fusion is unlikely, much less a commercial development, but there is hope. A reasonable time frame may be half a century before we see a world powered by the same process which drives the Sun. It will be an almost entirely clean, limitless, reliable, and safe source of power.
Christopher Llewellyn Smith states some cold hard numbers that are worth mentioning again. The price of ITER is at least 13 billion Euros or $17 billion. This cost is justified and dwarfed by the magnitude of the energy usage on Earth which amounts to a $5 trillion dollar a year market (I checked some of these numbers and they seem approximately correct. Did you know that you can download the International Energy Agency's annual reports as an iPhone or iPad app?). Particularly shocking are the subsides to fossil fuels which are over $500 billion a year worldwide (I am not so sure about this number, but the United States alone subsides fossil fules to the tune of $10 billion a year) while the subsides to renewables are only $45 billion worldwide. Smith says that the renewable energy sources of wind, bio, geothermal, and marine will never be able to meet the world's energy needs a current consumption rates. We must use solar, fission, or fusion energy.
It is a curious thing to ask a scientist to speculate on the future, but these two scientists have indulged us with a time frame for achieving fusion. Maybe the middle of this century at best they say. What makes fusion so difficult?
The key to releasing the energy of the Sun is forcing the nuclei of atoms close enough together for them to overcome their electrical repulsion and allow the strong force which binds nuclei to merge the nuclei together. Such favorable conditions for atoms to smash into each other can only occur under extreme temperatures and pressures, like say at the center of a star, but it is almost impossible to hold a star on earth. Anything which is hot enough to undergo fusion is also hot enough to burn through any container, thus we must contain something without quite touching it. Enter the magnetic doughnut known as the tokamak. A tokamak is a toroidal or doughnut shaped container that uses magnetic fields to confine plasma. Plasma is a state of matter where all the atoms are ionized (the electrons that normally orbit the protons in the nucleus have escaped)—and at these temperatures the atoms contained in the tokamak are definitely ionized. Magnetic fields apply a force on the charged particles of plasma such that the plasma can be corralled and kept away from the walls of the container. In an actual tokamak huge magnets encircle the enclosure as shown in the figure here where the magnetic coils and the ITER plasma surface is shown. The colors and contour lines indicate the magnetic field strength which is not quite perfect, the lines are wavy, due to deviations from perfect symmetry in the structure because the tordioal magnetic field is made of a finite number of magnetic coils. The ITER tokamak will be huge. Check out the tiny little person (bottom left) in the image below.
The complexity of this machine is astounding. One key challenge that must be overcome is the confinement of the plasma in a controlled manner. The Confinement Topical Group will determine exactly how to accomplish the confinement and avoid the performance degrading effects of Edge Localized Modes or (ELM modes). The hotter the plasma is the more internal plasma pressure is that must be balanced by stronger magnetic pressure fields; we could view this system in analogy to a balloon where that the plasma is the air under pressure and balloon's walls are the magnetic fields. The exact ratio of the plasma's internal current, the physical size of the tokamak, and the torodial magnetic field is a carefully tuned parameter to balance the gas temperature and magnetic pressures which does not yet have a known optimal configuration (the goal is I/aB < 2.5 where I is the plasma current, a is the minor radius, and B is the toroidal field on axis). It has been observed that the ELM modes periodically become unstable and have breakouts. This creates a large energy flux in a short time, like that of a solar flare on the Sun, where hot plasma breaks free of the magnetic fields. When this occurs the plasma may touch the side walls of the tokamak and overheat the internal surfaces to many thousands of degrees. The side wall surfaces will be evaporated and eroded inside the plasma chamber. In this way the ELM modes result in the introduction of plasma impurities which contribute to raising the effective atomic number (the number of free protons per particle) of the plasma which results in greatly reduced fusion efficiency or even the halting of the fusion reaction entirely; the target is to keep the effective atomic number below two. The aggregate erosion is large and the lining of the tokamak walls may need be replaced often. In order to operate the machine continuously and cost effectively the ELM modes must be controlled. The control of ELM is paramount for a successful fusion tokamak. In the video below Alberto Loarte tells us a little more about the control of ELM modes and clever ways that the ELMs are dealt with.
The plasma instabilities inside a fusion reactor are a serious engineering challenge, but they are not a safety concern at all. Unlike a fission reactor, when a fusion reactor is compromised it does not go critical in a dangerous explosion (like a fission reactor would), instead it just fizzles out harmlessly. This technology is not perfect though because while some may claim that a fusion reactor would create no dangerous radioactive material in fact it would produce some radioactive material that would need to be handled. It is the walls of the reactor which will become slightly radioactive (through neutron activation). Conveniently though the half life of such radioactive waste materials is less than 100 years and could be entirely handled on site.
We should all be hoping for fusion. I spoke with Michel Claessens, the head of communications for ITER, and one of the questions I asked him was, what should the public know about fusion and ITER?
As much as possible. More seriously, I would be happy if people understood the differences between fission and fusion.
And he has a point I think. Most people simply don't understand what is at stake and what our options our. If you are reading this then you are already more informed than most. Tell people about the difference between fusion and fission and encourage your government (no matter what country you live in) to follow a wise energy policy. While I was writing this article the United States changed its funding proposition for ITER which was a welcome change because at one point the United States looked like it would falter on its commitment to fusion research and ITER completely. This is an investment in our future and the Earth. I asked Claessens a question about this topic too, how important is worldwide collaboration in achieving a successful ITER project?
Worldwide collaboration is useful and even necessary - to pool and ensure the best use of resources (human and financial). The ITER project is so complex that no single country has the scientific and technological skills to build the machine alone. In addition, the international collaboration was seen by ITER fathers (Gorbachev and Reagan) as a way out to cold war.
The idea of harnessing the power of the Sun on the Earth is so much more than just a scientific endeavor. It is a very human dream to hold the Sun (what culture does not have some kind of original creation story or explanation for the sun?) and it is possible that realizing this dream may bring us together for all of the right reasons.
A Trip to the Moon (French: Le Voyage dans la lune) is a 1902 French black-and-white silent film by Georges Méliès. It was extremely popular at the time of its release, and is the best-known of the hundreds of fantasy films made by Méliès. A Trip to the Moon is considered the first science fiction film with its use of innovative animation and special effects. It is based loosely on two popular novels of the time: Jules Verne's From the Earth to the Moon and H. G. Wells' The First Men in the Moon. The film depicts six brave astronomers who build a space capsule and a huge cannon which shoots them into space. On the moon the astronomers find the unexpected.
