closing thoughts

Over the past several weeks I have learned an incredible deal of astrophysics. while, my understanding may only be the tip of the iceberg, The knowledge I have gained has completely changed my thoughts about astrophysics and astronomy. I always knew that a certain amount had to go into collecting data, but I never understood all of the physics and detail that goes into using a satellite to view the cosmos.
I didn't understand that there must be specific filters to eliminate other light. The noise from everything else has to be drowned out to focus on what one want's to study. Also, the light that is observed is very specific to certain transitions within atoms.
I used to think that astrophysics used already known theories from our understanding of our world and tried to extrapolate those concepts throughout the universe. While that is somewhat true, some major data for condensed matter has only been possible because of data astrophysicists have gathered. I also had the misconception that astronomers were not so restricted by there technology, but I have learned that there is a lot of error and restriction that are constantly being pushed with new ways of using technology. I have also learned about the limitations involved with certain technologies. Things as simple as telescopes, given even ideal conditions, are limited due to diffraction and seeing involved in the atmosphere and the very nature of light.
I will continue to learn more about astrophysics because i believe there will be new discoveries across many fields of physics. From massive planets moving at a fraction the speed of light, to newly discovered and analyzed subatomic particles like neutrinos, and even to super condensed matter in neutron stars that is even more dense than the nuclear matter within the nucleus.

making connections

Astronomy is not only an environment to study the very large, but it is also one of the only places for other fields to realistically study and test their theories. For example, gravitational relativity is nearly impossible to study on Earth, but some minor effects can be viewed on the massive scale from the cosmos. Nothing leaves at such great velocities from our galaxy as sub atomic particles, but it can be very difficult to study the motion of these particles, but some new results have shown something much BIGGER leaving our galaxy at some fairly incredible speeds.

Several years ago, astronomers were intrigued when they noticed runaway stars fleeing the milky way at millions of miles an hour. While this is only a few tenths of a percent of the speed of light, if a star could be hurled out of the galaxy at these speeds, could the same or even more extreme velocity happen to a planets. Not only do these runaway planets exist, but some have been clocked at a zooming 30 million mph. This is even more significant as it is a few percent of the speed of light.

Such speedy worlds, called hyper-velocity planets, are produced in the same way as hyper-velocity stars. When a binary star system wanders close to a super-massive black hole, the tremendous gravitation forces rip the pair apart throwing one at .03c Astrophysicists have shown that if a star orbiting a black hole were ejected out of the galaxy, the planets orbiting the star could go along with it.

Hyper-velocity planets would be nearly invisible at such high speed with current telescopes, but some of the basic understanding about orbiting planets could lend a helping hand in discovering them. If the planet were orbiting a star, there is a chance that it could transverse across the star resulting in the apparent dimming of the star. In order for these hyper-velocity planets to remain in orbit around their hyper-velocity stars, they must have incredibly fast orbital periods and incredibly small orbits. This means that the chance of witnessing one of these high speed transits, given that there is a planet orbiting a hyper-velocity star, is about 50%.

With a one-in-two chance of finding a transit due to a planet orbiting a hyper-velocity star, it would be foolish to ignore them. By monitoring these planets, new studies and experiments could test already known theories about the universe.

New data providing more support for star creation

The image on the right was captured using NASA space satellite, Swift. Using a combination of X-ray and ultraviolet imaging allowed astronomers an improved lens to get a more accurate view at specific stars as well as their activities. Swift was recently used to view a type 1a supernova. Supernova originate with a remnant star called a white dwarf. The use of X-ray and UV light allows researchers to witness the events and matter that cause such unknown phenomenon. Astronomers are still unsure on the environments of these supernova. New data from Swift reveals a clearer picture of what is required to make these detonate.
The new research has led researchers from Harvard to suggest that one of the white dwarf in a binary system absorbs matter from the other white dwarf. It feeds on very particular matter until it reaches a critical mass necessary to explode into one of these supernova. This data would help solve one of the greatest mysteries about how stars end their lives as stars.
The field of astrophysics is still growing rapidly every day. This is because of the limited resources, not only caused by budgets, but also because of current technological limits. New data from new sources using more accurate technologies is required in order for astronomers to make better use of their limited view from our position in the galaxy.

ile it’s been known that Type Ia supernovae originate with a remnant star called a white dwarf, the X-ray and ultraviolet views allow researchers to view the events and matter that cause the phenome

Source: redOrbit (http://s.tt/17Qgp)

way stars and galaxies under a new lens. A combination of X-ray and ultraviolet observations from NASA’s Swift satellite allow researchers to gain a more detailed look at specific stars and their activitie

Source: redOrbit (http://s.tt/17Qgp)

y stars and galaxies under a new lens. A combination of X-ray and ultraviolet observations from NASA’s Swift satellite allow researchers to gain a more detailed look at specific stars and their activities.

Source: redOrbit (http://s.tt/17Qgp)

y stars and galaxies under a new lens. A combination of X-ray and ultraviolet observations from NASA’s Swift satellite allow researchers to gain a more detailed look at specific stars and their activities.

Source: redOrbit (http://s.tt/17Qgp)

uts faraway stars and galaxies under a new lens. A combination of X-ray and ultraviolet observations from NASA’s Swift satellite allow researchers to gain a more detailed look at specific stars and their activities.

Source: redOrbit (http://s.tt/17Qgp)

uts faraway stars and galaxies under a new lens. A combination of X-ray and ultraviolet observations from NASA’s Swift satellite allow researchers to gain a more detailed look at specific stars and their activities.

Source: redOrbit (http://s.tt/17Qgp)

uts faraway stars and galaxies under a new lens. A combination of X-ray and ultraviolet observations from NASA’s Swift satellite allow researchers to gain a more detailed look at specific stars and their activities.

Source: redOrbit (http://s.tt/17Qgp)

new nuclear clock with unparalleled accuracy

The standard nuclear clock is actually based on atomic physics as opposed to nuclear physics. Atomic clocks are used in many scientific disciplines, such as for long-baseline interferometry in radio-astronomy as well as GPS systems and time signal radio transmitters. They are used for their extremely high precision, but that may change in the near future. the new proposed time keeping technology is tied to the orbiting of a neutron around an atomic nucleus. It could have such unprecedented accuracy that it neither gains nor loses 1/20th of a second in 14 billion years. This nearly 100 times more accurate than the atomic clocks we use today. Scientists could be able to better test fundamental physical theories at unprecedented levels of precision and provide an unmatched tool for applied physics research. This could also assist fundamental physics and system synchronization in particle accelerators and improve further diversified applications previously unreachable by atomic clocks. It is much better than standard atomic clocks because the neutron is held so tightly to the nucleus and its oscillation rate is almost completely unaffected by any external perturbations, unlike those of an atomic clock's electrons, which are much more loosely bound. Simply put, this new nuclear clock with unparalleled accuracy could be the new technology that helps probe science with more detail.

quasars and consequence of technology

Many of us know of black holes, but not so much about quasars. Quasars are the result of a supermassive black hole WITH a large amount of accretion. The quasar is actually the area surrounding the black hole that can emit more power than 2 trillion suns.It is because they are so luminous that it is so very difficult to distinguish them from the galaxy moving around them.This is where the consequence of our technology becomes apparent. Our technology seems to limit our ability to observe some phenomenon. Even with our limitations, the universe is so large that there is always something to look at in the sky.

Astronomers have found several quasars that act as a magnifying glass to the galaxies shadowed by the quasar. This is both amazing and difficult because there is so much gravity at the quasar and the quasar is so bright. Because of these reasons, astronomers looked for the spectral imprint of galaxies using Hubble's sharp view to look for gravitational arcs and rings that would be produced by gravitational lensing. these are indicated by the arrows in these three Hubble photos. Quasar host galaxies are impossibly hard to see because the central quasar far outshines the galaxy and this also makes it difficult to estimate the mass of a host galaxy based on the collective brightness of its stars. This is another benefit of lensing quasars. The magnification of the image behind the quasar gives a good understanding of the gravity, and therefore mas, of the quasar host galaxy. The next step for astronomers is to catalog as many quasar lenses so that they can use the limited technology they have to discover things further into space and in greater detail.

death of a star

Hubble Space Telescope of the Rotten Egg planetary nebula

Stars like our own sun, will eventually run out of hydrogen and begin to collapse upon them-self. There is still some hydrogen burning, however, and this heats up the surface of the star which then expands, gets bigger, and turns into a red giant. Eventually the core becomes hot enough to cause the fusion of helium into carbon. When the core cools again, the upper layers will be ejected. This leaves just the core as a white dwarf. This entire process lasts over 10 billion years

Supernova 1987A Hubble Wide Field Image

Bigger stars, over 10 solar masses, begin by fusing hydrogen into helium and then fusing helium to carbon, but after that is done, the star still has enough mass to fuse the carbon into heavier nuclei, such as oxygen, neon, silicon, magnesium, sulfur and iron. After the majority is converted to iron and the star reaches it's limit, it collapses in under a single second resulting in a neutron star. The homologous collapse makes nearly every bit of matter surrounding the neutron star to smash onto the surface of the neutron star at the same time. This heats up the matter to billions of degrees and creates a supernova.





Here's a visually nice video of the birth and death of stars. I particularly like the expansion of the supernova around 2:15.
Although it should be possible to record an entire event, I do not think any of these were completely recorded but are representations of what we think had happened according to some real observations and models.

finally, a model bursting neutron star

 Plasma from a neighboring star gets pulled into the orbit of a neutron star, where it slams into the stellar surface( accretion), creating thermonuclear explosions. Image: NASA

 A neutron star in a cluster in Terzan 5 was monitored by several groups who claim to have viewed all phases of thermonuclear burning within the neutron star. groups from MIT, McGill University, the University of Minnesota, and the University of Amsterdam analyzed x-ray data from a NASA satellite. Researchers primarily focus on the crashing matter being pulled onto a neutron star by the stars intense gravitational pull, accretion. Accretion results in more matter, fuel, being added to the neutron star to a point where the star bursts with a volatile energy. This thermonuclear reaction can be detected and measured by x-ray satellites. The bigger the burst, the larger a spike found in the data. There are models that explain the frequency of the bursts relative to the amount of accretion. There should be more frequent bursts relative to more matter raining down on the neutron star, however, data has not reflected this side of the model. Alternatively, stars with low accretion should have large spikes in thermonuclear reactions separated by long measurable periods of time. This is the kind of data observed from Terzan 5.
While looking at Terzan 5, researchers noticed many small spikes relatively close together that resembled what a high-mass accretion rate neutron star would look like. At higher rates, the small spikes condense even more so and resemble an oscillating wave. A reason for this would be that the neutron star is gathering so much mass at one time that, somehow, the matter is heating up rapidly and fusing throughout the plasma evenly. One possible solution to this puzzle is the difference in the object being observed. Normally, neutron stars spin violently several hundred times a second, but the star viewed in Terzan 5 rotated at a mere 11 rotations per second. Perhaps the data for high accretion rates fitted so well was because the slow spin of the neutron star was negligible. This would mean a new model would have to be developed that incorporated the neutron star's spin. A justification for the dependance of spin in neutron star models would be that the tremendous spin of the neutron star creates friction between different layers of plasma and the neutron star which adds heat enabling fusion to occur.

The Neutron Star

I've always been interested in discovering the fundamental properties of the most basic of matter, but had never thought to look to the skies. The neutron star is absolutely phenomenal. When a Supergiant doesn't create enough pressure from its core,  it collapses. A neutron star is formed when a degenerate core of a Supergiant nears a limit, the Chandrasekhar limit, and collapses. The core is so massive, that the gravitational force-which is normally much weaker than the strong force- overpowers and pulls the matter closer. Even though there is no fusion within the core, there is still neutron degeneracy pressure that holds the star up. While they are no where near as massive as Supergiants, if there were even a modest neutron star of 1.4 M (that's about 10^57 neutrons) with a radius of about 10 Km, it's average density (deeper in the core has an even greater density) would be 6.65e17 Kg m^-3. This is huge even compared to the typical density of the atomic nucleus of 2.3e17 Kg m^-3. Such a mass would result in the acceleration of an object due to gravity to be 1.86e12 m s^-2 or 190 BILLION times that of Earth. This is so big that if one were to drop an object from a mere meter above the surface of a neutron star, using classical Newtonian mechanics, the object would crash into the surface at a speed of 1.93e6 m/s or .06 times the speed of light. This means that the result of so much mass in a compressed volume requires an accurate description of a neutron star to necessarily include special and general relativity.
It is clear hat such high densities have an odd effect on matter. The fluid of free neutrons within the neutron star can spontaneously pair, changing into bosons, such that they no longer are restricted by the pauli exclusion principle. This is significant because it means that this fluid could be a superfluid, one which has no resistance. So a swirling puddle of free neutron pairs could spin forever without ever slowing down. Also, as density continues to increase, it is possible for both the pairing of neutrons and protons to create a superconductor that carries no electrical resistance.

Galactic Car Crash

Above: Abell 520   Green: Hot gas which is evidence of collision. Blue is where majority of mass is, which is dominated by dark matter. Starlight from galaxies, derived from observations by the Canada-France-Hawaii Telescope, is colored orange

It is not terribly uncommon for galaxies to collide with one another, but astronomers using data from the Hubble space telescope have observed a puddle of dark matter left behind from two massive cluster galaxies. `There is a very low density of stars within galaxies. The galaxies are filled with different gases and when two galaxies collide, it is likely that the stars pass by each other without interacting, but generally the gas collides and is left behind. the results found involving dark matter, however, could challenge current theories about dark matter that predict galaxies should be anchored to the invisible substance even during the shock of a collision. While dark matter may be invisible, the effects can be seen. Dark matter can bend light moving by, essentially magnifying objects behind it called lensing. This technique led to a puzzle when observing Abell 520 though; the dark matter in  had collected into a "dark core," containing far fewer galaxies than would be expected if the dark matter and galaxies were anchored together. This means that many of the galaxies originally with the dark matter has gone drifting somewhere else. This challenges our understanding of dark matter which means more research and innovative ideas will have to be created to better understand dark matter. The current problem however is that there are not very many collisions between local galaxies which is the primary way of studying how dark matter effects its surroundings. The other main galaxy cluster, the bullet cluster, is inconsistent with Abell 520. The dark matter and the galaxies bound to it were different in each case. The different instances could mean that "some" dark matter is sticky and smashes with dark matter- slowing it down, while other types of dark matter can pass through each other without interacting much. One other possible issue from abell 520 is the limitation of hubble. It is entirely possible that there are in fact galaxies within abell 520, but they are so relatively faint that hubble is not able to resolve them.

Astrophysics Experiment for Grating and Imaging Spectroscopy,

Astrophysics Experiment for Grating and Imaging Spectroscopy (AEGIS), is a concept for a high-throughput, high-resolution, moderate cost, X-ray spectrometer. This is for a new high energy astrophysics mission proposed to NASA. High resolution spectroscopy has enhanced much of our astrophysical knowledge and AEGIS should have over 40 times the resolution in its .2-1 Kev (100-600nm) range compared to other projects such as the XMM-Newton RGS or Chandra Gratings. Greater resolutions allows AEGIS to distinguish between multiple bright light sources that are close to each other while also allowing more precise measurements. AEGIS will be the first observatory with sufficient resolution at E < 1 KeV to resolve thermally broadened lines in hot plasmas (T>10^7K) AEGIS will be able to observe so well because it uses advanced X-ray optics. The results from AEGIS, along with Hubble, will give an accurate description of the intergalactic medium. By observing light at high energies, AEGIS may be able to answer questions about: large scale structures and their evolution, how matter behaves near high density objects such as neutron stars, and what happens close to high gravity objects like black holes.