Water on Earth: Asteroids!?

There has always been much speculation over how Earth has always contained water. However, there is definitely a scientific truth: During the formation of the solar system, scientists know that the space was mostly permeated by hydrogen gas. When the Sun was forming, it generated a lot of heat, and this resulted in spherical distributions of temperature ranging from extremely hot to extremely cold, as a function of radius. Because of this, scientists can define boundaries where metals, rocks, ice and water could condense out of the hydrogen gas at certain temperatures! This is why, at present day, we can see how the inner solar system is composed of solely rocky planets, and past the asteroid belt in the outer solar system, there are jovian planets which are all mostly gas.

Now that there is proper context, it makes sense that water could not have condensed in the inner solar system, simply because it was too hot and the water would have vaporized. However, there is no problem with water condensing in the outer solar system. Here lies the basis of the water-comet theory: When the solar system was still early in its age and gravitational interactions were forcing collisions between bodies, an H2O-abundant comet reached Earth and crossed its orbital path, thus colliding with it. It also could have been multiple asteroids that delivered the goods, but regardless, the result is the same and the reasoning is sound. The purpose of this post is this: recently, new evidence for asteroids carrying water in other star systems has solidified the theory's ideas. "In observations obtained at the William Herschel Telescope in the Canary Islands, the University of Warwick astronomers detected a large quantity of hydrogen and oxygen in the atmosphere of a white dwarf (known as SDSS J1242+5226). The quantities found provide the evidence that a water-rich exo-asteroid was disrupted and eventually delivered the water it contained onto the star." This is profound because it proves that other systems also have asteroids that carry high volumes of water, and it most likely isn't a single case!

For more information: http://phys.org/news/2015-05-fresh-evidence-earth-asteroid-debris.html?utm_source=menu&utm_medium=link&utm_campaign=item-menu

The MESSENGER

Four years of prime orbiting experience around Mercury has given scientists on Earth a lot to smile about. The MESSENGER spacecraft, a probe built by NASA in an effort to study the closest planet to our Sun, has recently crashed into Mercury after its mission has been declared finished. The probe left Earth in 2004, reached Mercury in 2008, and has orbited the planet since 2011. Throughout all this time, MESSENGER has been sending meaningful data back to scientists about the rocky planet, but most notably about its magnetic field. In fact, the most valuable data about Mercury's magnetic field was taken in the fall of 2014 and in early 2015, when the probe flew as low as 15 kilometers above the surface - as compared to 200 and 400 kilometers as it used to. The purpose behind orbiting so low was to collect data on the intrinsic magnetism of rocks on Mercury's surface. The results of analysis showed that the magnetic field of Mercury is extremely ancient, dating back to 3.7 and 3.9 billion years old. This compares to the planet's initial formation, which is believed to be dated at approximately 4.5 billion years ago. "If we didn't have these recent observations, we would never have known how Mercury's magnetic field evolved over time," said Johnson, also a scientist at the Planetary Science Institute. "It's just been waiting to tell us its story." Besides Earth, Mercury is the only planet within the inner solar system known to host such a magnetic field. Interestingly enough, how did engineers even get MESSENGER in orbit around Mercury without it getting pulled into the Sun? Surely the gravitational interactions would have perturbed the probe out of its initial orbit, even the temperatures would have melted it! Thankfully, even though the challenges were immense, the engineering team managed to keep MESSENGER out of trouble by: 1. Attaching a protective sunshield to keep the side of the probe facing the Sun cool. 2. Designing specific elliptical orbits so that the probe would have time between each orbit to cool off. 3. Keeping it away from the Sun's gravitational pull by designing an orbital maneuvering system around Mercury. Talk about mission success!

Astronomical distances: The farthest galaxy to date

Humanity has achieved much since the invention of the telescope. We now have the technological capabilities to send highly mechanized large telescopes into space to see farther into the cosmos than we have ever seen before. In an effort to highlight a prime example of such success, recently, an international team of astronomers led by Yale University and UC Santa Cruz have discovered a galaxy that is more than 13 billion years old and have precisely measured the distance to it! The galaxy has been labeled EGZ-zs8-1, and it is the farthest galaxy observed to date. From some heavy physical analysis, the team has concluded that this galaxy is extremely active, meaning that it is forming stars at an incredibly fast rate. "It has already built more than 15% of the mass of our own Milky Way today," said Pascal Oesch, a Yale astronomer and lead author of the study. "But it had only 670 million years to do so. The universe was still very young then." To put it into perspective, it is forming stars 80 times faster than our own galaxy, the Milky Way. Now, how exactly did the team go about measuring an accurate distance to the EGZ-zs8-1? The original identification of the galaxy was provided by NASA's Hubble and Spitzer space telescopes, but the distance was measured by a device called the MOSFIRE instrument loaded on the W.M. Keck Observatory's 10-meter telescope in Hawaii. It is a multi-object spectrograph that can analyze physical phenomena in the infrared band of light. Using these technologies in conjunction allowed scientists to discern the peculiar colors of the early, massive galaxies and assisted in the understanding of star formation in the early Universe.
For more information: http://phys.org/news/2015-05-astronomers-unveil-farthest-galaxy.html#nRlv

Snapshot! HL Tau offers insight into planetary formation

Ever wondered about how the solar system came to be? Of course, there are plenty of existing explanations, but there has never been direct evidence of another planetary system forming in a proto-planetary disk. Well that information drought has quite possibly come to a close. An image taken by the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile has triggered a wide channel of discussion because that very image seems to resemble, what astrophysicists at the University of Toronto claim to be, a forming planetary system. That system was catalogued as HL Tau, and it is the first image of its kind to be a candidate for a proto-planetary disk in action. The reason why there is so much debate about the image is because some scientists view the gaps as too close together, meaning that the gravitational force between the bodies would have ejected the planets from the system earlier on. However, the research team led by Daniel Tamayo strongly suggest that this is not the case. They argue that the mechanism responsible for the close gaps is called special resonant configuration. This resonance implies that the planets have "specific orbital periods" because of the gravitational interactions with each other and thus avoid direct collisions. He has also created two videos with the distinct resonant and non-resonant situations, and showed how the resonant system is naturally stable and would be the most likely case. HL Tau is a relatively young system, so it is predicted that over billions of years, the planets in the system will be ejected or take extreme elliptical orbits around the host star. Regardless, HL Tau will yield fascinating clues in aiding us understand whether our solar system is a typical one for hosting life. For more information: http://phys.org/news/2015-05-astrophysicists-proof-famous-image-planets.html

Book Review: In Search of Dark Matter

I have been searching for a book to read on a scientific topic recently, and one that really piqued my interest was a book discussing dark matter. It is called "In Search of Dark Matter", written by Ken Freeman and Geoff McNamara. It attempts to explain the mystery of dark matter, and why it is puzzling the modern scientific world. It also simultaneously tries to provide appropriate historical context, and reaches across a variety of disciplines to get the message across. However, the most important aspect that this book contains is that it discusses modern, up-to-date research on dark matter. Most of the book's content strikes at the heart of the problem; for example, it talks about gravitational lensing, galaxy rotation curves, WIMPs (weakly interacting massive particles), and even alternatives to the entire dark matter theory itself. This work does not rely purely on one conjecture, rather it tries to open up the discussion so that nothing is left out. I highly value that trait, and am going to enjoy completing this book sometime soon. Here is the link to the book for anyone interested: http://www.amazon.com/Search-Matter-Springer-Praxis-Exploration/dp/0387276165/ref=sr_1_1?ie=UTF8&qid=1428002097&sr=8-1&keywords=in+search+of+dark+matter

The elusive IMBH in Omega Centauri

Recently, I have had the opportunity to examine Dr. Pryor's work. Among his work with globular clusters and dwarf galaxies, there were hints that the possibilities of IMBHs (intermediate mass black holes) existed in some of the systems studied. Relating to this field, the most notable celestial phenomenon is Omega Centauri. This system has undergone many classifications: Over two thousand years ago, Ptolemy catalogued it as a single star. In 1677, Edmond Halley classified it as a nebula. In the 1830s, John Herschel recognized it as a globular cluster. Now, astronomers are not so sure that Omega Centauri is a globular cluster, but in fact a dwarf galaxy that has had its outer stars stripped. You might be tempted to ask: What is the basis for the reasoning that Omega Centauri is a dwarf galaxy and not a globular cluster? It shares all of the properties of regular globular clusters, so what's the deal? It turns out that Omega Centauri, although similar to other globular clusters, is a bit more unique in terms of its physical description. It rotates faster than the general distribution of globular clusters, it is also highly flattened and contains many generations of stars (typical clusters only have one generation of stars). Furthermore, Omega Centauri is about ten times more massive than the average globular cluster, making it nearly as massive as a dwarf galaxy! Moreover, the speeds of stars closer to the center of the system are relatively incredibly higher than expected. The stellar velocities are directly tied to the mass of the cluster itself; the findings indicated that the mass of Omega Centauri was not enough to compensate for the speeds observed. Rather, the team at the Max-Planck Institute for Extraterrestrial Physics highly suggested that in order to properly account for the speeds observed, there would have to be a black hole at the center of Omega Centauri that has approximately 40,000 solar masses! Before any justified skepticism from the viewers, there is precedent for this type of research. There was a globular cluster in Andromeda classified as "G1" that shared these properties and had an IMBH in its center. This further supports the idea that Omega Centauri has an IMBH in its center as well! It is hypothesized that past interactions with the Milky Way caused Omega Centauri to distort, and it is also suggested that this system could be a possible model for black hole formation. For anyone interested, the link is here: http://www.spacetelescope.org/news/heic0809/

Behold! The first image of light as a particle and a wave!

Scientists throughout the 20th century have always worked to great lengths in order to conceptually understand the tenets of quantum mechanics. One of these great principles of quantum mechanics is the fact that light (or any other quantum object) can only interact with matter as either a particle or wave - never both at the same time. It is either one form or the other. The reason behind this is because of the fundamental nature of observing the quantum phenomena. For example, if an electron gun fires electrons at slits that have lengths smaller than the wavelength of the electron itself, then an interference pattern would emerge. If we ever try to observe the electron before it hits the slits, then we would need to use light to observe it (just like anything else). The problem is, as soon as we add light to the electrons, they will gain energy because of the photons (light particle) scattering off of the electrons! This will destroy the system and provide no meaningful results. Recently, a science team at EPFL (École Polytechnique Fédérale de Lausanne) came up with an interesting experiment that resulted in the first image of light behaving as a particle and a wave simultaneously! The trick was to think about the imaging process: instead of using light to image electrons, use electrons to image light. The way they did this was by setting up a laser that fired a pulse of light at a nanowire; this resulted in a standing wave radiating around the wire. Then the researchers shot electrons near the wire, forcing the electrons to scatter off the photons. Using the ultrafast microscope, they were able to image the interactions between the photons and the electrons! The bumps in the image are the accelerations of the electrons (changes in speed because of the collisions) at each part of the standing wave set up in the nanowire. This basically means that the standing waveform of light in the nanowire was successfully visualized by just using electrons! And don’t worry, these results do not invalidate any principles of quantum mechanics; in fact they reinforce them. In the image, we can see the standing waveform of the light, and we can simultaneously see the interactions. This proves that the electrons are physically interacting with the particles of light – the photons. Voila, light is both a particle and a wave!

Link: http://phys.org/news/2015-03-particle.html