Blog 5: Discovering Teenage Galaxies Billiions of Light Years Away

The main idea behind this article is summed up by a quote used in the article. Michael Rauch, one of the key players in the observations said, "But as often happens in science we got a surprise and found something we weren't looking for--."

Using ESO's Very Large Telescope a team of astronomers found faint light from billions of light years away, which are believed to be teenage galaxies which are considered the "building blocks of normal galaxies like our Milky Way." These galaxies have eluded detection previously because a large amount of time was required even with an 8-meter telescope like the VLT, and the amount of time needed greatly exceeded the normal observing time awards. However, the team of astronomers, which included Martin Haehnelt of the University of Cambridge, Michael Rauch and George Becker of the Observatories of the Carnegie Institution, and Andy Bunker of the Anglo-Australian Observatory, used even periods of poor weather, using the service mode to obtain the observing time they needed. These observations were actually done in order to measure a faint signal from intergalactic gas caused by cosmic UV background radiation. Instead however, they found "dozens of faint, discrete objects emitting radiation from neutral hydrogen in the ... Lyman-alpha line" which is a defined characteristic of protogalaxies. The light signal coming from this small piece of sky implies low star formation and a small amount of chemical enrichment which leads the team to believe that these are galaxies in early stages of formation. This discovery is "particularly exciting...[because] it opens the route to find large numbers of bulidng blocks of normal galaxies and that we will now be able to study in detail how galaxies like our Milky Way have come together", according to Haehnelt. The discovery of these galaxies also lends support to the theory of galaxy formation that suggests that gas accreted forms smaller protogalaxies, which then collide and merge to become the massive galaxies seen today.

Although I don't see this as one of the more exciting news releases I've read, the fact that further observations of galaxies like these will infact help us better understand our own galaxy is always encouraging. The fact that these observations were made in the service mode, when the weather was not always perfect I do enjoy though, because it shows that observations don't have to be controlled completely by the weather which is so often what happens. Because the time needed for this was so extensive, the ESO staff astronomers were actually responsible for carrying out the actual observations. This shows that those kinds of observations that need a much longer time than the usual observing time awards can be done, and are just as effective.

Reference: ESO. "Discovering Teenage Galaxies Billions Of Light Years Away." ScienceDaily 28 November 2007. 29 November 2007 .

Blog 4: Physicists See Similarities In Stream Of Sand Grains, Exotic Plasma At Birth Of Universe

In an article written on November 7, 2007, there was a new insight into the birth of the universe explained. These finding were initially reported in the Physical Review Letters by a team from the University of Chicago. The team, led by Sidney Nagel and Heinrich Jaeger, discovered that in their simple experiment, they found that granular particles bouncing off a target produced behavior that was similar to behavior being researched to simulate the beginning of the universe. The experiment was designed to explore the depths of physical properties in which the situation has been pushed beyond the state of equilibrium; which in this case was a jet of sand. The attempt was to answer: in what kind of conditions does a collection of molecules, sand grains or other particles behave like a liquid? The article explained that after experiment, the team found that “rapid collisions of densely packed particles produce the liquid state that we can see afterward, when everything flies apart”. The intriguing part came when compared with quark-gluon plasma experiments being conducted at Brookhaven National Laboratory using the Relativistic Heavy Ion Collider. There were a number of similarities found between the two experiments which were surprising because it was expected that quantum physics would dominate in the Ion Collider.

The reason I found this article to be intriguing was summed up in the article in a quote by Nagel stating, “that’s the amazing thing about physics. The laws you have at one level really are the same as at other levels… certain principles are just invariant. Conservation of energy and momentum- you can’t get away from these on any scale.” Even though this article was based mostly on physics, it shows that because there were such similarities to what is perceived to have occurred millionths of a second after the big bang, the only way to truly further science is to combine the disciplines together. Astronomers have been around for thousands of years, but the only hope for one day truly understanding the universe is to be able to understand other studies such as physics, chemistry etc.

University of Chicago (2007, November 7). Physicists See Similarities In Stream Of Sand Grains, Exotic Plasma At Birth Of Universe. ScienceDaily. Retrieved November 13, 2007, from http://www.sciencedaily.com¬ /releases/2007/11/071106164740.htm

Blog 3: Massive Black Hole Smashes Record

Astronomers have discovered what is thought to be the largest known black hole orbiting a star. This new object has a hot, highly evolved star as an orbiting companion which allowed it's mass to be measured to be between 24 and 33 solar masses. In 2006, Andrea Prestwich of the Harvard-Smithsonian Center for Astrophysics in Massachusetts, and a team of colleagues had observed the dwarf galaxy IC 10, which is located in the constellation Cassiopeia. Upon observations of this galaxy with NASA's Chandra X-ray Observatory, it was noticed that the galaxies brightest X-ray source(IC 10 X-1), showed sharp changes in brightness which suggested a star passing in front of a companion black hole. Using NASA's Swift satellite as well as observations from the Gemini Telescope in Hawaii, Prestwich and her team found that the star in IC 10 X-1, appeared to orbit in a plane that lies edge-on to Earth's line of sight, and using the speed at which the two stars orbited one another, calculations showed that the black hole must have a mass of at least 24 solar masses. These calculations were surprising to many however because it was believed that massive stars in our galaxy leave behind black holes of about 20 solar masses, and it seems that the IC 10 X-1 was born heavier than that.

I think it is exciting that we are continually increasing what appeared to be limits on the size of black holes in our universe. This shows that there is still an extensive amount of knowledge to be gained from space, which is encouraging for young astronomers like myself. The ability to break previous “records” also shows that we are in fact always getting one step closer to understanding the universe. However, I would be interested to read the article written about these observations to learn with what certainty they made observations such as the line of sight. Isn't it possible that if the perceived inclination of this eclipse is off, then the calculations of mass could as well be in accurate? The article only said that the star “appeared” to be edge-on in the Earth's line of sight but discussed nothing further. The other thing that bothered me about this article, although trivial was the concluding quote by Roy Kilgard of Wesleyan University. Kilgard said “Massive stars in our galaxy today are probably not producing very heavy stellar-mass black holes like this one, but there could be millions of heavy stellar-mass black holes lurking out there that were produced early in the Milky Way's history, before it had a chance to build up heavy elements.” Unless Kilgard made this perceived insight before these observations were announced, then anyone's (amateur or professional) response to his statement would be “duh”, because Prestwich and her colleagues just proved that there could be much more massive black holes in galaxies beyond our own.

Article found at: http://www.sciencedaily.com/releases/2007/10/071030112102.htm