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.
Perhaps at first the images seem like the brush strokes of artist infatuated with geometry and abstract forms. Then precise patterns becomes unmistakable and you envision the path the spacecraft traced in space and its journey over space and time. The origin of the images only serves to heighten your realization of how amazing the universe is.
A dissociative galaxy cluster is a cluster of galaxies that just can't keep it together any longer. This may sound like an unnecessary anthropomorphication of galaxies, but it is actually a description of galaxy clusters which have collided and experienced stratification of their constituent parts. In the standard and successful model of cosmology the largest scale structures in the universe, like super clusters of thousands of galaxies, form via the merger of filamentary structures composed of smaller clusters of galaxies. Gravity keeps pulling clusters together along highways of galaxy clusters. Occasionally it is expected and observed that galaxy clusters meet each other head on in cosmic train wrecks moving at thousands of kilometers per second. These traumatic merging events scar the galaxy clusters for life. Their post traumatic stress afflictions include hot shocked X-ray gas and galaxies displaced from their gas halos. Lets consider the three main constituents of a galaxy cluster: stars, gas, and dark matter.
Clusters are made of aggregates of hundreds or thousands of galaxies and each galaxy is made of hundreds of billions of stars. The stars of the galaxy cluster are conspicuous in that they shine and are observable in pictures, but they account for only about 5% or less of the cluster's mass. The luminous stars of galaxies don't interact much during a collision with another cluster of galaxies and so they act like people in two crowds which are moving in opposite directions. Stars are part of the cosmic ghost train.
The gas in galaxy clusters accounts for about 10% of the regular (or baryonic) mass in clusters. Gas does interact during a collision. The gas clouds in colliding galaxy clusters slams together like two waves of water meeting and stalls out, but not without undergoing a process known as shock heating first which raises the gas temperature to millions of degrees.Gas is part of the cosmic train wreck.
The dark matter in galaxy clusters is the most dominant part of the cluster by mass making up about 90% the mass. Dark matter does not interact much. The dark matter halos travel right through each other like ghosts when two clusters collide. However, it is possible that the dark matter does interact slightly and dissociative collisions are a powerful tool in constraining this dark matter interaction. The dark matter halos of the colliding clusters should sail right past each other like two ghost trains, but if the trains slow down even in the slightest it may indicate something strange.
These so called dissociation mergers are difficult to observe and analyze. They require telescopes in space, follow up observations on the ground, observations in multiple wavelength regimes, and algorithms to predict the distribution of dark matter. So far there are six such dissociation mergers systems detected. You would think it would be obvious to spot some of the most massive structures in the universe smashing into each other, but spotting galaxy clusters is actually very difficult because of their great distance. Perhaps in an optical survey, like that in the image below taken by the Hubble Space telescope, over densities of galaxies are detected.
In practice many times it is easier to first identify galaxy clusters through their gas content because the gas content is more massive than the stellar component. Many new clusters are identified by observing the cluster gas's effect in the microwave regime or in the X-ray regime. In the image below taken by the the NASA Chandra X-ray observatory the hot intracluster gas is seen in pink. This image corresponds to exactly the same field of view on the sky as the optical image above.
It may dawn on you that by the very definition of dark matter there is no telescope which can observe it directly. The only in way in which dark matter interacts strongly is through gravity and thus that is how astronomers look for it. Through theoretical predictions and confirmed observations we know that gravity bends light and thus massive galaxy clusters will bend the light of even more distant galaxies. Thus through weak gravitational lensing the dark matter betrays its presence. A careful statistical analysis of galaxy shapes in the optical image above reveals that the galaxies which are confirmed not to be in the foreground cluster are slightly distorted in shape via the gravitational force of the dark matter which is in the foreground. A reconstruction of the total mass in the clusters is shown in the image below where the parts of the cluster which have the most mass are shown in blue. This image corresponds to exactly the same field of view on the sky as optical and X-ray images above.
Finally, a superposition of all the data allows us to glimpse at what a crisis this merging cluster is in. Note that the optical image remains in its original color, the gas is in pink, and the mass is in blue. The image below is known as the Musket Ball Cluster. The actual collision of galaxies occurred about 700 million years ago. We can rewind the collisions in our heads and envision that blue/optical cluster on the right of the image was once on the left and so the blue/optical cluster on the left of the image was once on the right; the clusters collided head on and the gas stopped dead at the center, but the galaxies and dark matter hardly stopped. There are several other images below of other dissociative cluster mergers with the same color scheme. Notice the different morphologies and distributions of mass, stars, and gas. The collisions are not always so straight forward.
Musket Ball Cluster. X-ray: NASA/CXC/UCDavis/W.Dawson et al; Optical: NASA/STScI/UCDavis/W.Dawson et al.
Train Wreck Cluster. X-ray: NASA/CXC/UVic./A.Mahdavi et al. Optical/Lensing: CFHT/UVic./A.Mahdavi et al.
Bullet Cluster. Credit: X-ray: NASA/CXC/CfA/M.Markevitch et al.; Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al.; Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al.
The awesome thing about these cosmic mergers is how they can constrain the dark matter self-interaction cross-section. That is, exactly who much does dark matter interact with itself? The interpretation of these collisions is not always simple such as in the Train Wreck Cluster (seen above) where there seems to be an extra dark matter core not associated with any bright galaxy at the center of the image, but nonetheless these mergers can be thought of as astrophysical laboratories of dark matter. It would be very interesting to discover that dark matter self-interacts at all, however dissociate clusters will only be one piece of the extraordinary evidence necessary to make that claim.
Dawson, W., Wittman, D., Jee, M., Gee, P., Hughes, J., Tyson, J., Schmidt, S., Thorman, P., Bradač, M., Miyazaki, S., Lemaux, B., Utsumi, Y., & Margoniner, V. (2012). DISCOVERY OF A DISSOCIATIVE GALAXY CLUSTER MERGER WITH LARGE PHYSICAL SEPARATION The Astrophysical Journal, 747 (2) DOI: 10.1088/2041-8205/747/2/L42
Jee, M., Mahdavi, A., Hoekstra, H., Babul, A., Dalcanton, J., Carroll, P., & Capak, P. (2012). A STUDY OF THE DARK CORE IN A520: THE MYSTERY DEEPENS The Astrophysical Journal, 747 (2) DOI: 10.1088/0004-637X/747/2/96
Markevitch, M., Gonzalez, A., Clowe, D., Vikhlinin, A., Forman, W., Jones, C., Murray, S., & Tucker, W. (2004). Direct Constraints on the Dark Matter Self‐Interaction Cross Section from the Merging Galaxy Cluster 1E 0657−56 The Astrophysical Journal, 606 (2), 819-824 DOI: 10.1086/383178
Peter Kareiva has surprisingly radical ideas on conservation. He is the chief scientist at the Nature Conservancy and is serious about protecting the Earth and all the creatures that depend on it. His views are unconventional in some ways. He argues that enviromentalism is on the decline and that we need to choose our environmental battles.
We are part of this Universe, but perhaps more important is that the Universe is in us. You may have even heard it stated as a fact that we are made of stardust. What does this mean? Well in the early early Universe, a few minutes after the big bang, the Universe consisted of only hydrogen, helium, and a smidgen of lithium. There was no oxygen, carbon, or any other heavy elements. Complex life had to wait. It took hundreds of thousands of years for stars to form. Eventually in the cores of massive stars the atoms of which we exist were forged under massive pressure and heat through the process of fusion—the merging of lighter atoms to create heavier atoms. The key to unlocking those delicious elements was fantastic stellar explosions. We could say the stars died for us.
Humans are at least 60% water by mass (this is the most uncertain number here because after you drink a few beers this number quickly starts to change). Water is by mass is 11% hydrogen. Thus the mass of hydrogen in our body from water is at least 7% though of course there is lots of other hydrogen in our body from other molecules (lipids, amino acids, and so on). A better estimate is that we are 10% hydrogen by mass (if we do our accounting by number of atoms in the body we are 63% hydrogen atoms). Ultimately every atom in us is that is not hydrogen was forged in stars, and so 90% of the mass in our bodies is stardust.
I can't tell if Charles Pellerin, the director of NASA astrophysics at the time the Hubble Space Telescope was launched in 1990, is a really honest person or a really lucky person. He was able to get a mission together that fixed Hubble after a disastrous design flaw was found in the telescope after it was already in space. In an article over at Computerworld he gives an account of the technical and social workings that led to the launch of Hubble with a spherically aberrerated mirror — the telescope's mirror was flawed such that it would take a space serving mission to make it usable for science. In 1993 a space mission did successfully fix Hubble, just three years after Huuble went to space as a deferred dream. In hindsight Pellerin believes what led to the mistake in Hubble's design, and the 1986 Challenger disaster, was as much technical as social. The pressure put on the rational scientists by management led to the problems.
Large projects have social forces at play such as 'normalisation of deviance' wherein problems become okay logically when you step back from them. An entire mission can drift noticeably into situations where more than a simple technical argument can stop it. Pellerin took notice of research which shows that social context can be a larger determinate of performance rather than individual abilities. Pellerin asserts that Hubble nor Challenger was a product of invisible or unmanageable forces. While certain accidents may be unavoidable, others are avoidable and they may be the fault of leadership. Today Pellerin teaches management techniques founded concepts of mutual respect, authenticity, and efficient action incorporated into the leadership.
There's nothing unusual about having a bad day at the office. But some people have worse days than others, and in his time Charles (Charlie) Pellerin has had a few notable ones. Not many people find themselves having to explain why an organisation has invested a decade and half and in the vicinity of $3 billion on a project that has failed.
That's the position Pellerin found himself in as NASA's director of astrophysics in the wake of the 1990 launch of the Hubble Space Telescope, which had what appeared to be an unfixable flaw in its optical system.
It's difficult to overstate what a disaster this was and the humiliation faced by NASA; not just as an organisation but also the individuals who worked for the agency. A good friend of Pellerin who worked on the telescope fell ill in the wake of the launch and died. Two of Pellerin's senior staffers had to be removed from their offices by guards and taken to alcohol rehab facilities. "These are PhDs sitting at their desk getting drunk; this is how bad the stress was," says Pellerin.
It is a fact that I have written more fiction in my life than science writing and more science writing that I have scientific papers. When my advisor has asked me to write I am able to naturally come up with an abstract and an introduction like a magician pulling a rabbit out of a hat. I summarize the current state of the field neatly and present our results as the natural evolution of what comes next. Then when it comes to writing out the details of the research and the work I slow down. My advisor has a bit of criticism about the introduction (it is not specific enough they say), and plenty of criticism for the rest of the writing as if my entire style is not adequate. What is with the style of science writing in grants and research papers?
It as if scientists are bound to a certain kind of writing that is dry, concise (and it has to be when we have to pay per page published in most research journals), and standardized. I think many scientist would agree that our language doesn't have to be dry as long as it is standardized. Expository writing is different from other kinds of writing sure, but we have to ask ourselves how and why? Science writing for journalism is different than that of science writing for papers of grants even though they are both technically expository writing. I wonder if this is because they must be or because mediocre writing has become the style in science papers. Adam Ruben has written a wonderful opinion piece over at Science magazine mocking some of the quirks of scientific paper writing. The piece is worth a read and he includes a list of science paper tropes which are hilarious. Here is an excerpt:
1. Scientific papers must begin with an obligatory nod to their own relevance, usually by citing exaggerated figures about disease prevalence or other impending disasters. If your research does not actually address one of these issues, pretend it does, because hey, that didn’t stop you on the grant application. For example, you might write, “Twenty million children die of scabies every day. OMG we built a robot kangaroo!”
2. Using the first person in your writing humanizes your work. If possible, therefore, you should avoid using the first person in your writing. Science succeeds in spite of human beings, not because of us, so you want to make it look like your results magically discovered themselves.
3. Some journals, such as Science, officially eschew the passive voice. Others print only the passive voice. So find a healthy compromise by writing in semi-passive voice.
ACTIVE VOICE: We did this experiment.
PASSIVE VOICE: This experiment was done by us.
SEMI-PASSIVE VOICE: Done by us, this experiment was.
Yes, for the semi-passive voice, you’ll want to emulate Yoda. Yoda, you’ll want to emulate.
A primer of what entropy is or is not at 3 Quarks Daily by Rishidev Chaudhuri and Jason Merrill:
C.P. Snow famously said that not knowing the second law of thermodynamics is like never having read Shakespeare. Whatever the particular merits of this comparison, it does speak to the centrality of the idea of entropy (and its increase) to the physical sciences. Entropy is one of the most important and fundamental physical concepts and, because of its generality, is frequently encountered outside physics. The pop conception of entropy is as a measure of the disorder in a system. This characterization is not so much false as misleading (especially if we think of order and information as being similar). What follows is a brief explanation of entropy, highlighting its origin in the particular ways we describe the world, and an explanation of why it tends to increase. We've made some simplifying assumptions, but they leave the spirit of things unchanged.
Cabinet Magazine has an interesting cultural perspective on human's attempts to zoom in and out of nature in the vertical. Particularly they focus on one of my favorite science films ever, Power of Ten.
Powers of Ten was originally inspired by a 1957 book by the Dutch educator Kees Boeke titled Cosmic View. By 1963, the Eameses were experimenting with tracking shots that gave the effect of a camera pulling away with accelerating motion from an object, and in 1968 used these in a film called A Rough Sketch for a Proposed Film Dealing with the Powers of Ten and the Relative Size of Things in the Universe. Shot in black and white, it was followed by an extended color version—the one known as Powers of Ten—made in 1977. The basic set-up of the latter film is well-known. It opens with a picnic scene in a park in Chicago. From a ground level view, the camera then switches to a vertical, aerial position from which it looks down, the frame centered—as we later find out—on an atom in the man’s hand. At this point the narrator tells us that we are one meter away and looking at a square one meter by one meter. Now the camera pulls away vertically and begins to accelerate so that every ten seconds our distance from the initial scene is ten times greater. The camera continues its upward trajectory until just after 1024 meters (100 million light years) when it gradually slows and begins its descent, collapsing beyond its original position and now decelerating through the ever-smaller dimensions of cells, molecules, atoms, and beyond.
A bright object has appeared conspicusouly in the outer spiral arm of the local galaxy M95 38 million light years away in the constellation Leo. This new illumination in M95 is probably a supernova. While supernova are not all that rare throughout the entire universe, a supernova occurring this close is rare and interesting as it is a chance to gather higher fidelity data. Conveniently Mars happens to currently be, by projection, right next to M95 so if you look at Mars in the next few days consider what lurks beyond. Unfortunately you need a telescope to see the object.
A scale model of our solar system in twelve 500 page volumes printed-on-demand. On page 1 the Sun, on page 6,000 Pluto. The width of each page equals one million kilometres.
This film takes us through the first volume where we encounter the Sun, Mercury, Venus, Earth, Mars and the Asteroid Belt.
Yes, this is just a film of someone flipping through a book that is the solar system to scale. Highlights include the Earth at minute 4:00, Mars at 5:25, and the asteroid belt at 6:40 (actually this is interesting because while even the sun fits on just two pages the asteroid belt spans for several minutes). The entire 12 volume set is available for the discerning and precise sky aficionado. Strange. Cool. Want.
Thorium may be the nuclear fuel of the future. It is clean, abundant, and safe. Check out this video made by the crafty folks at motherboard.tv documenting the grassroots movement to bring back thorium from the dustbin of history.
Proffesor Frédéric Pont at the University of Exeter has simulated what sunsets on planets orbiting distant stars would look like.
What does the sunset look like on HD 189733 b? Amazingly, we know quite accurately. This is because the colour of the sunset is exactly what is measured when collecting the transmission spectrum of the atmosphere of a transiting planet. We have measured the transmission spectrum of ’189 with the STIS spectrograph on the Hubble Space Telescope. STIS covers visible wavelengths, and HD 189733 is bright enough that the precision of the spectrum is sufficient for a precise translation into colours perceived by the human eye.
I’ve been saying for a few years that optical science has entered a truly remarkable new era: instead of asking the question, “What are the physical limitations on what light can do?”, we are now asking, “How can we make light do whatever we want it to do?” Among other things, we can make light travel “faster than light“, we can focus light through a highly scattering material, we can take high-resolution pictures with low-resolution sensors, and even make particles “fly” on a “wind” of light!
Inevitably, though, many of these discoveries get misinterpreted in popular news accounts to the point that their real significance is lost in a haze of science fictional, or even supernatural, hype. A good example of this is the “picosecond camera” that I described last week, which is an amazing achievement but also possesses a number of technical limitations that make it not quite a “camera” in the ordinary sense of the word.
This week, the experimental realization of a “space-time cloak” or “temporal cloak” by researchers at Cornell University has made national news.
