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Ngumi Mirie
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Size Matters Not

The new Star Wars movie Rogue One won’t arrive until December, but hype for the movie is already at a fever pitch. A new teaser poster has been released showing the Death Star looming over the horizon of an alien world. It makes for a foreboding shot, but could a Death Star really appear so large in the sky?

In the original Star Wars movie, the Death Star has the appearance of a “small moon.” The size of this Imperial superweapon isn’t specifically mentioned, but the technical specifications list its diameter as about 120 kilometers. That’s larger than the moons of Mars, but tiny compared to our own Moon, which has a diameter of about 3,400 km. If the Death Star orbited Earth at the same distance as our Moon, it would have the same apparent size as Venus at it’s brightest. In other words, it would look like a bright planet rather than a moon.

In the words of Master Yoda, “size matters not.” Or more accurately, size is only one factor among many. The key is what’s known as apparent size, which depends upon both the actual size of an object and its distance from you. A small but close object can appear bigger than a larger object far away. So what if it’s simply a matter of the Death Star being close to the planet? While that would help, it wouldn’t solve all the problem. In the Rogue One teaser poster it looks like the Death Star spans about 40 degrees across the sky. With a bit of basic trigonometry we find it would need to be about 180 km away to have such a large apparent size. That’s closer than the International Space Station, and so close that atmospheric drag would be a serious problem.

So the Death Star can’t be so close it spans half the sky, but it could be close enough to appear larger than our Moon. For example, if the superweapon were 1,000 kilometers above the Earth, its apparent size would be about 8 times that of the Moon, making it by far the largest object in the sky. We would be able to see surface features of the Death Star such as those depicted in the poster. To our minds it would appear huge, but its actual apparent size would still be pretty small. The Moon itself has an apparent size of only half a degree. If you held your pinky up at arms length it would easily cover the Moon. Even if the Death Star had an apparent diameter 8 times larger, you could still cover it with two fingers at arms length.

While the Death Star couldn’t appear so large in real life, there is still a way to give it a deceptively large appearance. Photographers do it with our Moon all the time. The trick is to use a telephoto lens to focus on a distant object near the horizon, such as a building or tree line. The apparent angle of a distant building is small, but zooming in makes it look big. This also makes the Moon look much larger than it actually is. Using this trick the Death Star could be made to loom over a battlefield, as depicted in the poster.

In the Star Wars universe a good photographer might be able to such a shot after all.

The Death Star appears huge in a new poster for Rogue One. Could a death star actually appear so large in real life?
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A More Perfect Union

On 26 December 2015 the LIGO observatory saw another merger of two black holes. This time the black holes were smaller, with masses of about 8 and 14 Suns. As a result, we captured the inspiraling of the black holes for a longer time. Gravitational wave astronomy is now fully under way.

Because of the size and distance of this merger (about 1.4 billion light years) this particular merger is fainter than the first. It was seen a periodic fluctuation buried within the LIGO noise, so the data has to be matched to computer simulations to really determine its properties. It’s statistical validity dances around the usual five sigma range, so there is no doubt the signal is real.

More than the first merger, this is a textbook example of a merger. We captured nearly thirty orbits of the two black holes as they danced ever closer to each other. We can see not only the steady gravitational waves of their orbits, we can also see how their orbital periods get shorter, orbiting ever faster as they approach the merger. This is textbook behavior. It is exactly the type of event we expected to see. The merging of stellar-mass binaries.

Overall this new observation is further confirmation not only of general relativity, but of central aspects of astrophysics. Black holes are real, they occasionally merge just as we predicted, and we can now start using gravitational waves as an astronomical tool.

Paper: B. P. Abbott et al. GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence. Phys. Rev. Lett. 116, 241103 (2016) DOI: 10.1103/PhysRevLett.116.241103

The second detection of a black hole merger confirms the success of gravitational wave astronomy.
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Lost At Sea

Our small world orbits a star in a cosmic sea. Our Sun sails through the galaxy with over 200 billion of its siblings. This sea of stars has many names: Silver River, Lugh’s Chain, the Merchant’s Road, but its most common name is the Milky Way. It’s a delicate veil of light, astonishing in its fragility and grandeur. It’s appearance has been central to the folklore of cultures across the globe. That’s because there was a time when the Milky Way could be seen at some point of the year from anywhere in the world. But that’s no longer true.

While the Milky Way is always there, it’s also rather faint. As humanity has moved from campfires to electric lights the amount of light pollution has increased. In recent years the rise of LEDs has further reduced our view of the night sky, since the bluish color of LEDs is particularly bad in terms of light pollution. We’ve now reached the point where a third of the world can no longer see the Milky Way. In Europe more than 60% are unable to view that starry veil, and in North America it’s hidden from more than 80% of the population. A cosmic phenomena seen for millennia is now being banished from view.

It’s easy to dismiss as a minor loss unless you’ve actually seen the Milky Way with your own eyes. Anyone who has stood under a clear night sky remembers it. It’s appearance is transformative. It fills you with wonder, and for years afterward you will tell the story of that time you truly saw the Milky Way. It’s loss is not simply a fading of the night, it’s a disconnect from our cultural heritage. No matter where your ancestors hailed, they looked up and the great starry veil in amazement. They told stories of it, and wondered of its origin.

If you haven’t seen the Milky Way, make it a priority. Give your children an experience they will remember for the rest of their lives. Make a connection to the cosmic sky that is your birthright. For if we lose it, we will be a civilization lost at sea.

Paper: Fabio Falchi, et al. The new world atlas of artificial night sky brightness. Science Advances, Vol. 2, no. 6, e1600377 (2016) DOI: 10.1126/sciadv.1600377

Only 1 in 5 Americans can see the Milky Way.
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The Fading Truth

By some estimates the rogue world has been cold for about 100 billion years. What atmosphere it once had was long gone, and for most of its life the world sailed between the starry sea of the supergalaxy. But for the first few billion years of its existence it had orbited a star. Under the warmth of a sun, life arose. Remnants of life on the world are faint, but unmistakable. And then there is the beacon.

The beacon was designed to be found. The region around the beacon contained an abundance of elements strikingly different from the surrounding regions. The beacon itself was clearly designed to survive billions of years. Whatever else this species was, they were amazing engineers. They used those skills to create a vast archive of their civilization. A beacon that declared their existence to the cosmos.

Much of the archive is still confusing. They were a collection of individual organisms that seemed to communicate through gestures and the creation of vibrations in their atmosphere. Social interactions between organisms were clearly important, but their behavior as a social collective was often contradictory. Their scientific data has proved much more tractable.

It’s not too surprising, given that they were curious creatures. Their understanding of chemistry is as expected, as well as most of their physics. From the archive it is clear they were based upon carbon and nitrogen. Their records indicate an atmosphere comprised mainly of nitrogen and oxygen, and their world orbited a yellow star within its temperate zone. Water played a central role in the organisms.

But within their scientific records is a perplexing tale of the origin of the universe.

The present universe consists of the supergalaxy, a great cluster of perhaps 50 billion stars. Beyond the supergalaxy is the great abyss, cold and dark where nothing exists but empty space. How this universe came to be remains a mystery, but the dominant view is that of an ageless cosmos. While stars form within great clouds of gas and dust, and die when they have consumed too much hydrogen in their core, new stars can arise from the old. The ageless universe model does have some difficulties with things like thermodynamics, but a steady state cosmos is the most reasonable model given the appearance of the universe.

But the archive tells a different tale. The Universe, it says, began as a very dense, very hot state. Over time it expanded and cooled, creating a mixture of hydrogen and helium. Eventually the hydrogen and helium coalesced under gravity to form not a single galaxy, but billions upon billions of galaxies. Some as large as the supergalaxy, others much smaller. Stars formed within these galaxies, fusing hydrogen and helium into the heavier elements such as carbon and iron. Heavier elements such as gold were formed from the collisions of neutron stars. In this tale the First Density formed space and time itself, with only hydrogen and helium as the first elements. It is the tale of a finite cosmos, in stark contrast to the steady state model.

If it were true, the early abundances of the elements would have been dominated by a specific ratio of hydrogen and helium. But over billions and billions of years that ratio has long been scrubbed by the fusion of hydrogen in stellar cores.

If it were true, there should be a thermal remnant of the event. A cosmic background of radiation that echoes the hot dense past. But over time any such background has faded to the point that it is invisible against the thermal noise of gas and dust within the supergalaxy.

Even with those clues long faded, there still should be evidence of other galaxies. Even if the galaxies were billions upon billions of light years away, their light should still be seen, perhaps faintly. But the tale makes even other galaxies invisible. The universe has not only expanded from the First Density, but has expanded at an ever increasing rate. Over a hundred billion years, other galaxies have raced away faster than light. Because of this accelerated expansion all other galaxies have passed beyond the veil of darkness. They are out there, the tale declares, but now forever invisible.

It is a truly perplexing tale.If the tale is true, then this species could have seen a sea of galaxies among a cosmic background. The cosmic story it presents does agree with the present universe, but there is now no way to test it or refute it. Its truth rests entirely on whether this ancient species is to be trusted. Did these creatures rely upon testable observations? Did they adopt scientific models even when they were perplexing or troubling, trusting the evidence to lead the way? Or did they create a convenient truth as a way to impose a beginning upon an endless universe. Like stars, these creatures were born, lived for a time, and died. Did they impose their finite life upon the universe to assuage some social need?

The tale presents two paths: either rely upon the evidence of present observation, or rely upon past evidence of a fading truth. Neither path seems entirely satisfactory.

Paper: Lawrence M. Krauss, Robert J. Scherrer. The return of a static universe and the end of cosmology. General Relativity and Gravitation, Volume 39, Issue 10, pp 1545–1550 (2007) DOI: 10.1007/s10714-007-0472-9

The tale presents two paths: either rely upon the evidence of present observation, or rely upon past evidence of a fading truth.
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The Challenge Of Proving Black Holes

While the evidence for black holes is pretty conclusive, the extreme nature and odd physics of black holes has encouraged skepticism about their existence in certain circles. While highly dense objects exist, they argue, that doesn’t mean such objects are black holes. On some level they have a point, because there are proposed objects that are black-hole like, but not true black holes, such a gravastar.

A gravastar is an extremely dense object where the behavior of quantum gravity somehow kicks in to prevent the formation of a singularity and event horizon, which are the most contentious aspects of black holes. In some models it is assumed there is a minimum scale (Planck length) where gravity stops functioning in the usual way, while in others dark energy kicks in at small scales to prevent the formation of a true black hole. In either case a gravastar would look quite similar to a black hole.

When gravitational waves were detected this year, it was seen as definitive proof of black holes. The gravitational “chirp” and ringdown detected by LIGO was an exact match of a black hole merger, and even allowed us to determine the masses of the initial and final black holes. It confirmed the existence of gravitational waves, which was the last great prediction of general relativity. Since general relativity predicts black holes quite clearly, the result is pretty definitive. But it is true that black holes should depend upon quantum gravity, which we don’t yet fully understand. If quantum gravity resulted in gravastars, would the LIGO detection look any different? It turns out the answer is yes, but not in a way we can currently detect.

According to the models, gravastars are so dense they have collapsed almost to the point of being a black hole. The merger of two gravastars would still have a chirp and ringdown of gravitational waves. The ringdown of a gravastar merger would differ slightly from that of black holes, but only at the tail of the ringdown. Of course that part of the ringdown seen by LIGO is buried in the background noise of the data. Thus, the gravastar supporters would argue, the LIGO event detected either a gravastar or black hole merger, but can’t distinguish one from the other.

Does that mean the existence of black holes is in limbo? Personally I don’t think so. While gravastar models argue against black holes, there’s no compelling argument for gravastars. While they do resolve certain theoretical conundrums black holes have, gravastar models have problems of their own. Not the least of which is the fact that they depend upon heuristic arguments of quantum gravity that may or may not be valid. So on the whole I don’t find the gravastar model particularly compelling. There’s also the risk of playing the denialism game regarding black holes, where no amount of evidence will ever be seen as sufficient. To be clear, I don’t think gravastar supporters are playing the denialism game. It is good to be skeptical of new work, and the gravastar model is one way to test the limits of our observations.

That’s all part of the challenge of doing science.

Paper: Vitor Cardoso, et al. Is the Gravitational-Wave Ringdown a Probe of the Event Horizon? Phys. Rev. Lett. 116, 171101 (2016) arXiv:1602.07309 [gr-qc]

What if black holes don't exist, but similar objects do? How would we tell the difference?
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Cassini and the Ninth World

The Cassini spacecraft currently orbiting Saturn has provided us with a wealth of discoveries. It’s mapped the surface of Titan, studied the age of Saturn’s rings, and found liquid water on Enceladus. But because it actively sends and receives radio transmissions to and from Earth, it’s position and movement can be tracked with extraordinary precision. Using the telemetry of Cassini, we’ve been able to determine the position of Saturn to within a mile. That level of precision also means the gravitational influence of other planets and moons can be measured by Cassini, and it may have felt the gravitational pull of the yet undiscovered ninth planet.

The existence of the a ninth major planet in our solar system was first proposed by looking at the orbits of the outermost known bodies in our solar system. If they were truly at the outer edge of our solar system, one would expect their orbits to be randomly distributed. But instead they are clustered in a similar region, implying the presence of a large planet orbiting the Sun at 600 – 1,200 AU. Recently a team realized that if such a planet existed, its gravitational tug could be felt by bodies closer to the Sun as well. Normally this pull would be far to small to notice, but the extreme sensitivity of Cassini might make it known. So they analyzed the orbital data of Cassini. Taking into account the 8 known planets, the moons of Saturn and about 200 of the largest asteroids, they found Cassini’s orbit didn’t quite match up. This would imply something unaccounted for is gravitationally influencing the probe. When they added a ninth planet to the mix, they found it could agree with Cassini’s motion if the planet was about 600 AU from the Sun in the direction of the constellation Cetus.

The result isn’t definitive. There are lots of things that could account for the motion of Cassini, and an undiscovered planet is just one of them. However if it is a new planet, with a distance of “only” 600 AU it should be detectable by current technology such as the dark energy sky survey or the Planck survey of the cosmic microwave background. If that’s the case, it’s only a matter of time before a new planet is discovered in our solar system.

Paper: A. Fienga, et al. Constraints on the location of a possible 9th planet derived from the Cassini data. A&A, 587 L8 (2016) arXiv:1602.06116 [astro-ph.EP]

The Cassini spacecraft orbiting Saturn may have felt the gravitational pull of a ninth planet.
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Seeing Gravitational Waves With Atomic Clocks

Now that gravitational waves have been observed, the race is on to design better and more sensitive gravitational telescopes. The LIGO telescope measures gravitational waves by precisely measuring the distance between reflectors. As gravitational waves pass through LIGO the distance changes very slightly. One way to improve over LIGO is to create a more sensitive telescope in space following similar designs, such as the proposed eLISA mission. But there are other ideas that are also worth considering, such as designs using atomic clocks.

While atomic clocks can measure time very precisely, they can also measure the frequency of laser light very precisely. If two satellites containing atomic clocks were put into a common orbit, laser signals from each satellite could be measured by the atomic clock in the other. If a gravitational wave passed by, it would cause a small oscillation between the satellites, which could be seen an a periodic Doppler shift of the laser signals.

One advantage of such an experiment is that it could be tuned to gravitational waves of a particular frequency, rather than having a range of frequencies such as LIGO. Such a narrow band sensitivity would make it a poor detector of black hole mergers, but it could detect gravitational waves from periodic sources such as binary neutron stars. In a recent paper outlining the idea, the authors propose such atomic clocks could be included in an eventual eLISA mission.

Right now this is just an idea, but in the new world of gravitational wave astronomy, a lot of ideas could soon become reality.

Paper: S. Kolkowitz, et al. Gravitational wave detection with optical lattice atomic clocks. arXiv:1606.01859v1. (2016)

Atomic clocks could be used to observe gravitational waves in a new way.
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Exoplanet Water Hiding Under Cloudy Skies

Hot Jupiters are the most numerous of known exoplanets. These are large Jupiter-sized planets that orbit very close to their parent star. Because these planets have thick atmospheres, they are among the few exoplanets where we can actually study the composition of their atmospheres. This has led to an interesting mystery, where many hot Jupiters are seen to have water vapor in their atmospheres, while others appear bone dry. It now seems that the seemingly dry exoplanets could have water vapor in their atmosphere, but it’s simply hidden by a layer of clouds.

The atmospheres of exoplanets are studied by looking at how light from a star gets absorbed as an exoplanet passes in front of it. This means it’s only the upper layer of the atmosphere that we can study. Anything below a layer of clouds or haze won’t be seen. In a new study, a team of astronomers looked at 19 hot-Jupiter exoplanets. Evidence of water vapor was found in 10 of them, while the other 9 showed no evidence of water. They then looked at an overall spectrum of light from these exoplanets, and compared them with models of clear atmospheres and hazy atmospheres. They found that for most of the planets about half the light from their atmosphere is blocked by clouds and haze.

If most hot Jupiters have a cloudy haze layer, then it could explain why some appear so dry. When the bulk of water vapor is below the hazy layer, then it would appear dry. If some water vapor is above the cloud layer, then it would be seen. This doesn’t mean that all dry hot Jupiters have hidden water vapor, but it is consistent with the idea that most hot Jupiters should have water vapor in their atmospheres.

Paper: Aishwarya R. Iyer et al. A Characteristic Transmission Spectrum dominated by H2O applies to the majority of HST/WFC3 exoplanet observations. ApJ 823 109 (2016) arXiv:1512.00151 [astro-ph.EP]
Some large exoplanets may hide their water beneath a layer of clouds and haze.
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Hair Of The Dog

According to general relativity, if you gather together enough mass into a small enough space, you can create a black hole. No matter what kind of matter you use (cars, protons, old issues of National Geographic) the black hole you get will have only three properties: mass, electric charge, and rotation (angular momentum). This is known as the no-hair theorem, because the material properties of any object (referred to as “hair” because a physicist named John Wheeler once coined the phrase “a black hole has no hair”) become unmeasurable (hence unknowable) as the object collapses into a black hole. While it seems a simple enough idea, it’s caused all manner of problems for theoretical physicists.

To begin with, the no-hair theorem is in direct conflict with another principle of physics, namely that information about an object can’t simply disappear. In physics, information about an object tells us what’s going on. Since events are caused by what happened before them, and allow us to predict what will happen next, the amount of information we have about a system must be conserved. But a black hole violates this rule. Once an object enters a black hole, all information about it effectively disappears.

In classical relativity there’s no way around this problem. It’s generally thought that quantum gravity would solve the issue, but even that path has been plagued with problems. One of the thing quantum gravity predicts is that black holes should leak a small amount of energy over time due to Hawking radiation. A popular idea has been that perhaps Hawking radiation isn’t simply random, but carries information about what has fallen into the black hole. However this approach led to another problem known as the firewall paradox. Basically, Hawking radiation is caused by quantum fluctuations in spacetime. In order to carry information they must also create a firewall of superheated particles near the black hole’s event horizon. This violates the central idea of relativity known as the equivalence principle.

Arguments over these ideas and their theoretical implications have raged for years, but recently Stephen Hawking and his colleagues have devised a possible solution. It starts with a subtle property of quantum theory.

In classical physics, a “vacuum” is simply a region of space in which there is nothing. In quantum theory “nothing” is hard to define. Because of things like the Heisenberg uncertainty principle a vacuum is filled with a sea of quantum fluctuations that average out to zero. Usually it is assumed that there is just one vacuum state in quantum theory, however there is a way to have an infinite number of quantum vacuum states.

Imagine a vacuum of space with a single photon, but make the energy of the photon so tiny that it’s essentially zero. In classical physics this would just reduce to the standard vacuum, however in quantum physics it would reduce to a unique vacuum state. Since you can do this in basically an infinite number of ways, you can create an infinite number of vacuum states. Normally this would just be theoretical mumbo-jumbo, since all these quantum vacuum states would yield the same physics in the end. But with black holes it could solve the information paradox.

The idea of Hawking and his peers is that a black hole is surrounded all these unique vacuum states, forming a kind of quantum hair (or soft hair, as they call it) around the black hole. By itself the soft hair looks just like a classical vacuum, but it can contain the information of all the stuff that fell into a black hole. The Hawking radiation emitted by the black hole is random (thus preventing the firewall paradox), but it interacts with the soft hair of the quantum vacua, releasing the information they contain (thus solving the information paradox).

If this model is right, then it means information isn’t lost after all. It’s just hidden in a quantum vacuum, waiting to be released by Hawking radiation.

Paper: Stephen W. Hawking, Malcolm J. Perry, and Andrew Strominger. Soft Hair on Black Holes. Phys. Rev. Lett. 116, 231301 (2016)

It turns out that black holes might have hair after all.
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Astronomers Probably Discovered 1,284 New Planets

NASA’s Kepler mission has announced the discovery of 1,284 newly confirmed planets, raising the total confirmed exoplanets to more than 3,000. While this is a big step forward in exoplanet astronomy, it is also part of a shift in how exoplanets are discovered. That’s because these new planets weren’t discovered individually, but rather through an automated algorithm that gives candidate planets a statistical thumbs up or down.

The Kepler spacecraft discovers planets by measuring the varying brightness of stars in a small region of sky. As a planet passes in front of a star (such as the recent transit of Mercury) the star dims by a small but measurable amount. By watching for dips in brightness that repeat on a regular basis, astronomers can verify that a planet is orbiting a star.

In principle the process is straight forward, but in practice it can be extremely difficult. Stars have some natural variation in brightness due to things like solar flares, and starspots moving across the surface of a star can look quite similar to a transiting planet. So there is always the potential of getting a false positive. There have been instances where a planet was added to the list of confirmed exoplanets and then later removed upon further analysis. It takes careful analysis to distinguish a real planet from a poser, and it isn’t something that can be done quickly by hand. But Kepler has observed nearly 150,000 main sequence stars, and there it simply isn’t practical to go through all of that data by hand.

Enter statistical analysis. Rather than pouring over data by hand, a team of astronomers wrote a program to determine the odds of an exoplanet being a false positive, based on a comparison to known false positives. They had the program analyze data from more than 7,000 “objects of interest” in the Kepler data, which at first glance look like planetary transits. They found that about 2,000 of them had less than 1% odds of being a false positive. Some of these had previously been confirmed by other means, but 1,284 have not been confirmed previously.

Given the odds, it is likely that about 100 of these new exoplanets will later be outed as false positives. So it’s a bit misleading to say that exactly 1,284 new exoplanets have been confirmed. However the exact number isn’t important. This method allows us to narrow down the amount of exoplanet data. Now that exoplanets number in the thousands, we have to shift our methods away from sorting through data by hand and rely on statistical algorithms. And that’s an amazing shift. We have so much exoplanet data and so many exoplanet candidates that we can’t keep up. It’s a dramatic change from just two decades ago when only a handful of exoplanets were known.

Paper: Timothy D. Morton, et al. False Positive Probabilities For All Kepler Objects Of Interest: 1284 Newly Validated Planets And 428 Likely False Positives. The Astrophysical Journal, Volume 822, Number 2 (2016) DOI:10.3847/0004-637X/822/2/86

Astronomers have found 1,284 candidate exoplanets with less than 1% odds of being a false positive.
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Black Hole Alignment Is Not So Mysterious

There’s news of a mysterious alignment of black holes. While that makes for good headlines, the actual scientific findings aren’t so mysterious.

The research has just been published in MNRAS, and it looked at the orientation of black hole jets. When black holes consume matter, the heat and pressure of the surrounding accretion disk can throw some of the material away from the black hole at tremendous speed. This material streams away from the black hole forming long trails we call jets. Since these jets always stream away from the poles of a rotating black hole, the alignment of the jets tells us the orientation of the black hole.

The team looked at distant black holes across a 1-degree span of sky, which is about twice the apparent width of the Moon. When they looked at the jets of black holes in this area, they found an apparent alignment. The chance of such alignment occurring randomly is about 0.1%, so it is likely that something caused them to have similar alignments. This is “mysterious” because the black holes are not close enough to each other to be interacting. So there is no way for them to be tugging each other into alignment.

However this kind of alignment is not unexpected. Computer simulations of the cosmos show that intergalactic material should be rotationally aligned along filaments between superclusters. We’ve seen similar alignments among quasars, which is indicative of this large filament structure. So what this work actually shows is further evidence of the large scale filament structure as predicted by computer simulations. The authors are clear to point this out, and don’t claim there is anything mysterious about it.

Unfortunately, “we’ve found further evidence confirming cosmological models” doesn’t garner as many clicks as “Ooh! Mysterious black holes!”

Paper: A. R. Taylor and P. Jagannathan. Alignments of radio galaxies in deep radio imaging of ELAIS N1. MNRAS Vol. 459 L36-L40 (2016). doi:10.1093/mnrasl/slw038

There's news of a mysterious alignment of black holes. While that makes for good headlines, the actual scientific findings aren't so mysterious.
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Earth-Like Protoplanet Around A Young Star

TW Hydrae is the closest T Tauri star, only about 180 light years away. T Tauri stars are young stars in the late stages of formation. This means any planetary system they have are also in the early stages, so they give us insight on just how planetary systems form. Studying these early planetary systems can prove difficult, since they consist largely of cold gas and dust, which can be challenging to observe. But recent observations from the Atacama Large Millimeter/submillimeter Array have given us the most detailed images of TW Hydrae yet, and they are kind of amazing.

The protoplanetary planetary disk of TW Hydrae happens to be face-on from our perspective, so ALMA has a very clear view of the disk’s structure. As with other young planetary systems, the disk has gaps indicative of early planet formation. With this observation and others, it is clear that young stars form planetary systems from the gas and dust of a protoplanetary disk. But this system is particularly interesting because it shows a gap at about 1 astronomical unit, which is the distance of the Earth from the Sun. It’s close to the resolution limit of AMLA, but there is a clear gap. So we now have evidence of Earth-distance planets forming in a solar system.

Paper: Sean M. Andrews, et al. Ringed Substructure and a Gap at 1 AU in the Nearest Protoplanetary Disk. The Astrophysical Journal Letters, Volume 820, Number 2 (2016) arXiv:1603.09352 [astro-ph.EP]
A young star shows evidence of forming an Earth-like world.
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Origin.The ancient Egyptian name,Meri-Amun,meaning "beloved of the sun god Amun"when adopted by the Isralites was recorded in the bible as Miriam.The sister of the famous Moses who led the Isralites to the promised land of Canaan was called Miriam.The Latin adopted the name as Maria which form appears in most Western European languages.Mary is the English Bible Version.The Ethiopia versions Maryam and Mariam unlike in Europe where it is a female baptisimal name have been used as patronymics/surnames for ages.Some examples of well known Ethiopians with the patronymic are;Emporor Takla Maryam(1430-1433) of the Solomonic Dynasty,Emporor Baeda Maryam (1468-1478) and more recently Mengistu Haile Mariam who was head of state between 1977 and 1991.And the current Ethiopian Prime Minister HailleMariam Desalegn.The introduction of the name to giküyüland(Central Kenya)came about either in the late 1700s or early 1800s during the period in Ethiopian history reffered to as Zamana Masafint or" Era of the Prince" when there was protracted conflicts between the many claimants of the seat of the emporor populary known as the king of kings(Nègusa Nagäst)Among the group of royals who escaped the terror of Ras Sehul the powerful Tigrean Warlord were several women with the title Waizero.One of the women,escorted by some men among them Kassa and Tefere reached an area now known as Dagorreti and settled there.The woman was carrying a boy whose name was Mariam which the Agiküyü adopted as Miríí.Though Waizero was a title(Married Woman or the equivalent of Dame in the court titles of Ethiopian Nobility) the Agiküyü were not to know that and they called her Waithera,so,the boy grew up to be known as Miríí wa Waithera and is the originator of the family by the name Mbari ya Mirie.The boy is my anscestor and it is partly the reason why I have a fairer skin color than most kikiyus.
Bragging rights
Able to relate to matters of science while lifting weights.I know a thing or two about the origin of the universe and at my weight of 152lbs(70 Kgs) My PB deadlift is 330lbs(150 Kgs) and I am aiming a bit higher than that.
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