Dark matter has been found to be (unexpectedly) evenly distributed across dwarf galaxies, rather than clumping together in the centre - in the way we that we had expected of 'cold' dark matter.
Dark matter – there’s a growing feeling that we are getting closer to finding out the true nature of this elusive stuff. At least we are running a number of experiments that seem (on theoretical grounds) to have the capacity to identify it – and if they don’t… well, maybe it’s time for a rethink of the whole ball game.
There are two arguably quite separate requirements for dark matter to make sense of our current dataset and our theoretical schema for the universe. Firstly, the Standard Model of cosmology (Lambda-Cold Dark Matter) requires that 96% of the universe is composed of stuff of an unknown nature that cannot be directly observed.
Shown at lower right is the "Violin Clef" galaxy merger. Click for larger image. Credit SDSS
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About a month ago, a Galaxy Zoo contributor named Bruno discovered a very unique galaxy merger in the Sloan Digital Sky Survey data. The merger appeared to be a triple, or possibly quadruple system, which are indeed quite rare, and it includes curiously thin and long tidal tails. The Galaxy Zoo team has been informally referring to this merger as the “Violin Clef” or the “Integral” based on the unique shape as shown above.
What about this merger make it so interesting to scientists? What can they learn from these type of galaxy mergers?
Galaxy Zoo contributor Bruno had some insights on what makes the merger so interesting, stating: “These are some really beautiful tidal tails – They are extremely long and thin and appear curiously poor in terms of star formation, which is odd since mergers do tend to trigger star formation.” Bruno also added at the time of discovery: “There is no spectrum so we do not know the redshift of the object. It is also not clear if the objects at either end are associated or just a projection.”
(Note: Redshift is a term used to measure distance to distant objects. The higher the number, the older and more distant the object)
Based on Bruno’s curious discovery, the Galaxy Zoo team put in significant efforts to learn more about this merger. Galaxy Zoo team member Kyle Willett provided an update this week, highlighting several new insights, along with more information on this merger’s significance.
Close-Up view of Violin Clef galaxy merger. Image Credit: Sloan Digital Sky Survey ( http://www.sdss3.org )
One of the additional reasons the system is of scientific interest is that while merging galaxies are quite common in our universe, the merging process is fairly quick compared to the lifetime of a galaxy. What is not common is to observe a system with long tails and multiple companions, which gives researchers an opportunity to test their models of galaxy interaction against a system “caught in the act”.
Researchers are also interested in the content of galaxies and their tails – specifically the gas and stars. In most mergers, there is a compression of gas by gravity, which leads to a short burst of new star formation in the galaxies and their tails.
The resulting star formation results in young, hot stars which are typically blue. (Note: Younger/hotter stars are bluer, older/cooler stars are redder). What is odd about the Violin Clef merger is that all four galaxies and the tidal tails are red.
Willett stated “If that’s the case, then we want to estimate the current age of the system. Were the galaxies all red ellipticals to begin with, with very little gas that could form new stars?” Willett also added, “Or has the starburst already come and gone – and if so, how long-lived are these tidal tails going to be?”
By using analyzing the light given off by the merging galaxies, researchers can obtain a treasure trove of information. By measuring how much the spectra is redshifted, researchers can determine an accurate distance. In the case of the Violin Clef merger, an accurate redshift would let the team know for certain if all four galaxies genuinely belong to a single interacting group.
Once researchers have a distance estimate, they can study UV and radio flux data and determine an estimate of the total star formation rate. Additionally, if researchers have very accurate data from light received (spectroscopy), it’s possible to measure the relative velocities of each interacting galaxy, and build a sort of “3-D” picture of how the four galaxies are interacting.
Since there wasn’t any existing spectral analysis data of the merger system, Danielle Berg, a graduate student at the University of Minnesota, observed the Violin Clef in September using the 6.5-meter Multiple Mirror Telescope in Arizona and provided the additional data needed to answer some of the questions the Galaxy Zoo team had about the system.
Spectral analysis of the "Violin Clef" galaxy merger. Image Credit: Danielle Berg/University of Minnesota/Multiple Mirror Telescope
After the team analyzed the spectral data, they learned that all four galaxies are at the same redshift (z=0.0956 +- 0.002), and as such, are most likely members of the same group. Further analysis reinforced the lack of evidence for strong star formation, which helps to confirm the red colors see in the Sloan Digital Sky Survey data.
Based on these recent discoveries, the Galaxy Zoo team is putting out a second call for assistance on analyzing the Violin Clef merger. According to the team, the next step in the analysis will be working with simulations like the ones in Merger Zoo. Now that the team has confirmed the Violin Clef is almost certainly a quadruple merger, the number of merger models than need to be ran is greatly reduced.
How can citizen scientists help the Galaxy Zoo team with this step of their research?
You can start by visiting the Galaxy Zoo mergers project page at: http://mergers.galaxyzoo.org/
By participating in the Galaxy Zoo mergers project, you can identify simulations that resemble the Violin Clef. Your participation can also provide the Galaxy Zoo team with additional data which may enable them to have another scientific publication, plus these types of projects can be very fun and exciting to work with!
Learn more about becoming a Galaxy Zoo participant at: http://www.galaxyzoo.org/how_to_take_part
A Green Pea galaxy - which may be an local analogue of the univere's first galaxies. Credit: Galaxy Zoo/SDS.
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The ground-breaking discovery of a new class of galaxies, Green Peas, in 2009 by a group of Galaxy Zoo volunteers – have recently been followed up by further observations in the radio spectrum.
The Green Peas were first identified from Sloane Digital Sky Survey data – and then in Hubble Space Telescope archive images. Now radio observations of Green Pea galaxies (from GMRT and VLA) have led to some new speculation on the role of magnetic fields in early galaxy formation.
Green Pea galaxies were so named from their appearance as small green blobs in Galaxy Zoo images. They are low mass galaxies, with low metallicity and high star formation rates – but, surprisingly, are not all that far away. This is surprising given that their low metallicity means they are young – and being not very far away means they formed fairly recently (in universal timeframe terms).
Most nearby galaxies reflect the 13.7 billion year old age of the universe and have high metallicity resulting from generations of stars building elements heavier than hydrogen and helium through fusion reactions.
But Green Peas do seem to have formed from largely unsullied clouds of hydrogen and helium that have somehow remained unsullied for much of the universe’s lifetime. And so, Green Peas may represent a close analogue of what the universe’s first galaxies were like.
Their green color comes from strong OIII (ionised oxygen) emission lines (a common consequence of lots of new star formation) within a redshift (z) range around 0.2. A redshift of 0.2 means we see these galaxies as they were when the universe was about 2.4 billion years younger (according to Ned Wright’s cosmology calculator). Equivalent early universe galaxies are most luminous in ultraviolet at a redshift (z) between 2 and 5 – when the universe was between 10 and 12 billion years younger than today.
Spectroscopic data from Green Pea galaxy 587739506616631548 - demonstrating the prominent OIII emission lines which are characteristic of Green Pea galaxies. Credit: Galaxy Zoo.
Anyhow, studying Green Peas in radio has yielded some interesting new features of these galaxies.
With the notable exception of Seyfert galaxies, where the radio output is dominated by emission from supermassive black holes, the bulk radio emission from most galaxies is a result of new star formation, as well as synchrotron radiation arising from magnetic fields within the galaxy.
Based on a number of assumptions, Chakraborti et al are confident they have discovered that Green Peas have relatively powerful magnetic fields. This is surprising given their youth and smaller size – with magnetic field strengths of around 30 microGauss, compared with the Milky Way’s approximately 5 microGauss.
They do not offer a model to explain the development of Green Pea magnetic fields, beyond suggesting that turbulence is a likely underlying factor. Nonetheless, they do suggest that the strong magnetic fields of Green Peas may explain their unusually high rate of star formation – and that this finding suggests that the same processes existed in some of the first galaxies to appear in our 13.7 billion year old universe.
About a decade ago, standard cosmological models encountered a slight problem when applied to the Milky Way… missing satellite galaxies. While the calculations predicted as many as 500, only 10 are documented and modern figures state as many as 20. So what happened to the other 480 that should be out there? Either they don’t exist – or we can’t see them for some reason. Thanks to research done by the LIDAU project and two researchers from Observatoire Astronomique de Strasbourg, we might just have an answer.
About 150 million years after the Big Bang, the Universe’s first stars began to appear out of the cold, electrically neutral hydrogen and helium gas which filled it. As their intense light cut through the hydrogen atoms, it returned them to their plasma state in a process called reionisation. Things really began to heat up from there… gas began escaping the gravity of low-mass galaxies and as a consequence, they lost their star-forming abilities. By computing the observable consequences of this process, Pierre Ocvirk and Dominique Aubert demonstrated that the Milky Way’s first stars had the power of reionisation and it “is indeed an essential process in the standard model of galaxy formation.” This photo-evaporation state neatly explains the sparsity and age of Milky Way companions and offers up the reason satellite galaxies are rare in this neighborhood.
“On the other hand, their sensitivity to UV radiation means satellite galaxies are good probes of the reionisation epoch. Moreover, they are relatively nearby, from 30000 to 900000 light-years, which allows us to study them in great details, especially with the forthcoming generation of telescopes.” says Ocvirk. “In particular, the study of their stellar content with respect to their position could give us precious insight into the structure of the local UV radiation field during the reionisation.”
Current theory states this photo-evaporation was simply caused by nearby galaxies, resulting in a uniform event – but the new model built by the two French researchers proves this assumption wrong. Their high resolution numerical simulation accounts for the dynamics of the dark matter haloes from beginning to end, as well as their resultant gas impacted star formation and UV radiation.
“It is the first time that a model accounts for the effect of the radiation emitted by the first stars formed at the center of the Milky way, on its satellite galaxies. Indeed, contrary to previous models, the radiation field produced in this configuration is not uniform, but decreases in intensity as one moves away from the source.” explains Ocvirk. “On one hand, the satellite galaxies close to the galactic center see their gas evaporate very quickly. They form so few stars that they can be undetectable with current telescopes. On the other hand, the more remote satellite galaxies experience on average a weaker irradiation. Therefore they manage to keep their gas longer, and form more stars. As a consequence they are easier to detect and appear more numerous.”
Where did initial assumptions fall short? In previous models reionisation was thought to occur over an evenly distributed UV background, but the MIlky Way’s first stars had already done its damage by consuming its satellites. As the study suggests, our own galaxy is responsible for the lack of smaller companions.
Says Ocvirk; “This new scenario has deep consequences on the formation of galaxies and the interpretation of the large astronomical surveys to come. Indeed, satellite galaxies are affected by our galaxy’s tidal field, and can be slowly digested into our galaxy’s stellar halo. They can also be stretched into filaments and form stellar streams.”
It’s a very interesting new concept and will be one of the main science goals of the Gaia space mission, scheduled for launch in 2013. Until then, the Observatoire Astronomique de Strasbourg team will continue in their efforts to further understand radiative processes during reionisation.
This single all-sky image, captured by the Planck telescope, simultaneously captured two snapshots that straddle virtually the entire 13.7 billion year history of the universe. Credit: ESA
The universe has gone through a number of distinct phases. The first part of the first second is speculative, but the physics of the latter part is well know to us. In the first several minutes the lightest elements (hydrogen and helium) were formed.
Over the next 380,000 years the universe was a hot (but always cooling) plasma of electrons, nuclei and photons. At 380,000 years it was cool enough for electrons and nuclei to combine into atoms, in a process called recombination. The photons were freed from the plasma, and the universe became transparent for the first time. As the universe was opaque before recombination and transparent after, we see this epoch as a ‘wall’, and it is known as the cosmic microwave background.
What followed was a period known as the ‘cosmic dark ages’. The only light was that of the fading afterglow of the Big Bang, and the matter was comprised of the primordial elements and the exotic ‘dark matter’. During this time gravitational accretion slowly but surely produced larger and larger concentrations of matter, and when these became sufficiently dense, nuclear reactions could form and the first stars and galaxies were born. These lit up and ionized the universe again, some 400-500 million years after the Big Bang, in what is known as the ‘reionization epoch’.
The activity increased exponentially, culminating in the ‘quasar epoch’ 2-4 billion years after the Big Bang, a frenetic period of chaotic star and galaxy formation, galaxy interactions, monster quasars and radio galaxies. This activity eventually began to drop off, although it still continues today; the incidence of quasars today is a thousand times less than it was at the peak of the quasar epoch. At 13.7 billion years, the universe has now reached a ‘dignified middle age’.
The ‘heavy elements’ such as carbon and oxygen, essential for life as we know it, are all produced in stars, and this process has been going on ever since the first stars formed. Each generation of stars ejects more heavy elements into the intergalactic medium, so the abundances of the heavy elements have been built up over time.
By the time the Sun and Earth were formed 4.6 billion years ago, over 8.4 billion years of star and planet formation had already taken place in the universe. Star formation still takes place today, so in total there have been over 13 billion years of star and planet formation.
Zooming in now to our planet, life started not long after the Earth itself formed, sometime between 3.8 and 3.5 billion years ago (bya). But for almost half the age of the Earth, the only forms of life were microorganisms such as bacteria. More complex life forms started to appear about 1-2 bya. Invertebrates, which appeared some 600 million years ago (mya), were the earliest multicellular life forms, and vertebrates appeared about 500 mya. Life invaded the land about 400 mya. The dinosaurs dominated from 240 mya until their extinction 66 mya, and then mammals gradually took over. Many species came and went. Our closest living relatives are the chimpanzees, which split off from our ancestral line 5-6 mya; our more recent relatives have all become extinct.
It is amazing to think how recently humans appeared on the cosmic scene. Our species only appeared about 200,000 years ago, our ancestors emerged out of Africa just 50,000 years ago, agriculture started 10,000 years ago, and we have had modern technology for only the last 100 years or so! We are newcomers to the universe.
We now know that there are planets orbiting other stars like our Sun, probably billions of them in our galaxy alone, and billions more in the billions of other galaxies. Given the huge timescale of the universe, any life on those planets is bound to be millions or billions of years more or less advanced than life on Earth. If it is less advanced, it would certainly not be able to communicate with us. If it is more advanced, its technology would probably be totally unrecognisable to us. Nevertheless, we are probably not alone in the universe.
Of course the timescales discussed above only cover the ‘conventional’ universe from the Big Bang to now. If there was a ‘preexisting’ multiverse, we have no idea how far back any ‘before’ may extend. And as the expansion of the universe is accelerating, the future of the universe may be very long indeed: trillions upon trillions of years.
Peter Shaver obtained a PhD in astrophysics at the University of Sydney in Australia, and spent most of his career as a senior scientist at the European Southern Observatory (ESO), based in Munich. He has authored or co-authored over 250 scientific papers, and edited six books on astronomy and astrophysics.
This artist's conception shows a dwarf galaxy seen from the surface of a hypothetical exoplanet. A new study finds that the dark matter in dwarf galaxies is distributed smoothly rather than being clumped at their centers. This contradicts simulations using the standard cosmological model known as lambda-CDM. Credit: David A. Aguilar (CfA)
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Dark matter… If it can’t be seen, then how do we know it’s there? If it wasn’t for the effects of gravity, we wouldn’t. We’d have a galaxy filled with runaway stars and no galaxy would exist for long. But how it behaves and how it is distributed in one of the biggest cosmic cryptograms of all. Even with new research, there seems to be more questions than answers!
“After completing this study, we know less about dark matter than we did before,” said lead author Matt Walker, a Hubble Fellow at the Harvard-Smithsonian Center for Astrophysics.
It is generally accepted that our Universe is predominately composed of dark matter and dark energy. Of the former, it is considered to be “cold”, stately exotic particles which coalesce through gravitation. As they evolve, these dark matter “clumps” then attract “normal” matter which forms present day galaxy structures. Through computer modeling, astronomers have simulated this growth process which concludes that galactic centers should be dense with dark matter. However, these models aren’t consistent with findings. By measuring two dwarf galaxies, scientists have found a even distribution instead.
“Our measurements contradict a basic prediction about the structure of cold dark matter in dwarf galaxies. Unless or until theorists can modify that prediction, cold dark matter is inconsistent with our observational data,” Walker stated.
Why study a dwarf instead of a spiral? In this case, the dwarf galaxy is a perfect candidate because of its composition – 99% dark matter and 1% stars. Walker and his co-author Jorge Penarrubia (University of Cambridge, UK) chose two nearby representatives – the Fornax and Sculptor dwarfs – for their study. In comparison to the Milky Way’s estimated 400 billion stars, this pair averages around 10 million instead. This allowed the team to take a comprehensive sample of around 1500 to 2500 stars for location, speed and basic chemical composition. But even at a reduced amount, this type of stellar accounting isn’t exactly easy picking.
“Stars in a dwarf galaxy swarm like bees in a beehive instead of moving in nice, circular orbits like a spiral galaxy,” explained Penarrubia. “That makes it much more challenging to determine the distribution of dark matter.”
What the team found was somewhat surprising. According to the modeling techniques, dark matter should have clumped at the core. Instead they found it evenly distributed over a distance measuring several hundred light years across.
“If a dwarf galaxy were a peach, the standard cosmological model says we should find a dark matter ‘pit’ at the center. Instead, the first two dwarf galaxies we studied are like pitless peaches,” said Penarrubia.
It is hypothesized that interactions between normal and dark matter might be responsible for the distribution, but the computer simulations say it shouldn’t happen to a dwarf. New queries to new findings? Yes. This revelation may suggest that dark matter isn’t always “cold” and that it could be impacted by normal matter in unexpected ways.
A remarkable finding of the early 21st century, that kind of sits alongside the Nobel prize winning discovery of the universe’s accelerating expansion, is the finding that the universe is geometrically flat. This is a remarkable and unexpected feature of a universe that is expanding – let alone one that is expanding at an accelerated rate – and like the accelerating expansion, it is a key feature of our current standard model of the universe.
It may be that the flatness is just a consequence of the accelerating expansion – but to date this cannot be stated conclusively.
As usual, it’s all about Einstein. The Einstein field equations enable the geometry of the universe to be modelled – and a great variety of different solutions have been developed by different cosmology theorists. Some key solutions are the Friedmann equations, which calculate the shape and likely destiny of the universe, with three possible scenarios:
• closed universe – with a contents so dense that the universe’s space-time geometry is drawn in upon itself in a hyper-spherical shape. Ultimately such a universe would be expected to collapse in on itself in a big crunch.
• open universe – without sufficient density to draw in space-time, producing an outflung hyperbolic geometry – commonly called a saddle-shape – with a destiny to expand forever.
• flat universe – with a ‘just right’ density – although an unclear destiny.
The Friedmann equations were used in twentieth century cosmology to try and determine the ultimate fate of our universe, with few people thinking that the flat scenario would be a likely finding – since a universe might be expected to only stay flat for a short period, before shifting to an open (or closed) state because its expansion (or contraction) would alter the density of its contents.
Matter density was assumed to be key to geometry – and estimates of the matter density of our universe came to around 0.2 atoms per cubic metre, while the relevant part of the Friedmann equations calculated that the critical density required to keep our universe flat would be 5 atoms per cubic metre. Since we could only find 4% of the required critical density, this suggested that we probably lived in an open universe – but then we started coming up with ways to measure the universe’s geometry directly.
There’s a You-Tube of Lawrence Krauss (of Physics of Star Trek fame) explaining how this is done with cosmic microwave background data (from WMAP and earlier experiments) – where the CMB mapped on the sky represents one side of a triangle with you at its opposite apex looking out along its two other sides. The angles of the triangle can then be measured, which will add up to 180 degrees in a flat (Euclidean) universe, more than 180 in a closed universe and less than 180 in an open universe.
These findings, indicating that the universe was remarkably flat, came at the turn of the century around the same time that the 1998 accelerated expansion finding was announced.
Although the contents of the early universe may have just been matter, we now must add dark energy to explain the universe's persistent flatness. Credit: NASA.
So really, it is the universe’s flatness and the estimate that there is only 4% (0.2 atoms per metre) of the matter density required to keep it flat that drives us to call on dark stuff to explain the universe. Indeed we can’t easily call on just matter, light or dark, to account for how our universe sustains its critical density in the face of expansion, let alone accelerated expansion – since whatever it is appears out of nowhere. So, we appeal to dark energy to make up the deficit – without having a clue what it is.
Given how little relevance conventional matter appears to have in our universe’s geometry, one might question the continuing relevance of the Friedmann equations in modern cosmology. There is more recent interest in the De Sitter universe, another Einstein field equation solution which models a universe with no matter content – its expansion and evolution being entirely the result of the cosmological constant.
De Sitter universes, at least on paper, can be made to expand with accelerating expansion and remain spatially flat – much like our universe. From this, it is tempting to suggest that universes naturally stay flat while they undergo accelerated expansion – because that’s what universes do, their contents having little direct influence on their long-term evolution or their large-scale geometry.
But who knows really – we are both literally and metaphorically working in the dark on this.
Scientists have used ESO’s Very Large Telescope to probe the early Universe at several different times as it was becoming transparent to ultraviolet light. This brief but dramatic phase in cosmic history — known as reionisation — occurred around 13 billion years ago. By carefully studying some of the most distant galaxies ever detected, the team has been able to establish a timeline for reionisation for the first time. They have also demonstrated that this phase must have happened quicker than astronomers previously thought.
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The seasons are changing for both hemispheres and it’s not uncommon to wake up to wonderful, mysterious swirls of fog. What we experience here on Earth is water vapor, but the Universe was once filled with a fog of hydrogen gas. As the hours progress, the Sun slowly burns it off – quietly revealing trees, houses and the road ahead. In time after expansion began, the electrically neutral hydrogen gas was slowly swept away by the light of ultraviolet radiation from early galaxies…
Using the Very Large Telescope (VLT) like a “time machine”, a team of astronomers cut through the cosmic cloud layer to view some of the most distant galaxies recorded so far – a look back between 780 million and a billion years after the Big Bang. These antediluvian galaxies excited the gas, making it electrically charged (ionised), it gradually became transparent to ultraviolet light. While you may argue this process is technically known as reionization, there is theorized to be a brief timeline when hydrogen was also ionised.
“Archaeologists can reconstruct a timeline of the past from the artifacts they find in different layers of soil. Astronomers can go one better: we can look directly into the remote past and observe the faint light from different galaxies at different stages in cosmic evolution,” explains Adriano Fontana, of INAF Rome Astronomical Observatory who led this project. “The differences between the galaxies tell us about the changing conditions in the Universe over this important period, and how quickly these changes were occurring.”
As we know from spectroscopy, each element has its own signature – the emission lines – and the strongest in ultraviolet is the Lyman-alpha line generated from hydrogen. This bold spectral signature is easily recognizable – even at a vast distance. By observing the Lyman-alpha line for five very remote galaxies, the team was able to establish two critical factors: their distance through redshift and how soon they could be detected. Through this process, the astronomers were then able to establish how much the Lyman-alpha emission was reabsorbed by the neutral hydrogen fog and create a timeline… A whole lot like recording what minute each landmark reappears when terrestrial fog clears and seeing the long road ahead.
“We see a dramatic difference in the amount of ultraviolet light that was blocked between the earliest and latest galaxies in our sample,” says lead author Laura Pentericci of INAF Rome Astronomical Observatory. “When the Universe was only 780 million years old this neutral hydrogen was quite abundant, filling from 10 to 50% of the Universe’ volume. But only 200 million years later the amount of neutral hydrogen had dropped to a very low level, similar to what we see today. It seems that reionization must have happened quicker than astronomers previously thought.”
As always, there’s a bit more to the story. In this case, by understanding the rate at which the ancient absorbent obstruction began fading, scientists could also deduce the source of the powerful ultraviolet radiation. Could it be first generation stars – or even the work of primeval black holes?
“The detailed analysis of the faint light from two of the most distant galaxies we found suggests that the very first generation of stars may have contributed to the energy output observed,” says Eros Vanzella of the INAF Trieste Observatory, a member of the research team. “These would have been very young and massive stars, about five thousand times younger and one hundred times more massive than the Sun, and they may have been able to dissolve the primordial fog and make it transparent.”
To prove anything, it’s going to take a lot more research and some very accurate measurements – ones that are already in the planning stage for the future ESO European Extremely Large Telescope. But, in the meantime, the team used the great light-gathering power of the 8.2-metre VLT to carry out spectroscopic observations, targeting galaxies first identified by the NASA/ESA Hubble Space Telescope and in deep images from the VLT.
Do you love astronomy? Do you appreciate science? Do you have a curiosity about the nature of our Universe, how it came to be and what our place is within it? If you are even reading this I assume your answers to all of those questions is a resounding “yes!” and so I present to you an excellent video created by Brad Goodspeed in support of the James Webb Space Telescope:
“I made Vision because I thought the argument for science could benefit from a passionate delivery,” Brad told Universe Today. “Deep down we’re all moved by the stars, and that passion needs to be expressed by methods outside of science’s typical toolbox.”
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Funding for this next-generation telescope is currently on the line in Washington. While a markup bill was passed last month by the House of Representatives that allows for continued funding of the JWST through to launch, it has not yet been ratified by Congress. It’s still very important to maintain support for the JWST by contacting your state representatives and letting them know that the future of space exploration is of concern to you.
A petition against the defunding of the JWST is currently active on Change.org and needs your signature (if you haven’t signed it already.) Signing ends at midnight tonight so be sure to click here to sign and pass it along as well! (You can share this shortened link on Twitter, Facebook, etc.: http://chn.ge/oy4ibI)
The JWST will be the premier observatory of the next decade, serving thousands of astronomers worldwide. It will study every phase in the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of solar systems capable of supporting life on planets like Earth, to the evolution of our own Solar System. It is currently aiming for a 2018 launch date.
“We don’t get to the future by yielding to our most current fears… by being shortsighted.”
Concentric circles interpreted as bruises from collisions with alternate universes. Image Credit: Feeney et al.
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At the end of last year, there was a flurry of activity from astronomers Gurzadyan and Penrose that considered the evidence of alternate universes or the existence of a universe prior to the Big Bang and suggested that such evidence may be imprinted on the cosmic microwave background as bruises of concentric circles. Quickly, this was followed by an announcement claiming to find just such circles. Of course, with an announcement this big, the statistical significance would need to be confirmed. A recent paper in the October issue of the Astrophysical Journal provides a second opinion.
The review was conducted by Amir Hajian at the Canadian Institute for Theoretical Astrophysics. To conduct the study, Hajian selected a large number of circles, similar to the ones reported in the previous studies and asked what the probability was that, randomly, the “edge” of the circles would contain hot-spots, similar to the ones predicted. These were then compared to the bruises reported by the other teams by examining their “variance” which is how much the points on the perimeter were spread around the average temperature.
Hajian notes that, with the resolution considered it would be possible to consider some 5 million circles. The results of his comparison demonstrated that it would be expected that some 0.3% of those should have features similar to the ones reported previously. With so many possibilities, this would imply that some 15,000 potential circles could be flagged as candidates for these cosmic bruises. Even the “best” candidate proposed in the Gurzadyan and Penrose study should still exist statistically.
As such, Hajian concludes that the features Gurzadyan and Penrose reported were not statistically anomalous. Hajian does not comment directly on Feeney et al.’s detection, but given theirs were constructed in a similar manner, it should be expected that they are similarly statistically insignificant. It would appear that if the fingerprints of other universes are embedded in the sky, they have been lost in the noise.
