APOD 3.6

Today I chose to write about Spiral Galaxy NGC2841, which is a galaxy that is similar to our own in structure. In this picture it is easy to see the center of it and the hundreds of blue regions where thousands of new stars are being formed. The lanes that make up the spirals can also be easily seen which makes this picture even more astounding. The simple colors and shape of this picture are enough to make it simply amazing but the scale is even more unbelievable. This galaxy is about 300,000 light years across. This is an incomprehensible distance and is dwarfs even our own galaxy. This single galaxy probably contains millions of stars many of which have planets orbiting them and therefore poses many new possibilities for life to begin or already exist.

James Keeler Biography

Andrew Sanderson

24 February 2011

Astronomy Honors

Mr. Percival

James Keeler Biography

            James Edward Keeler was born in La Salle, Illinois on September 10, 1857. His most famous contributions to astronomy were that the rings of Saturn are composed of small particles and that there a very large number of spirals among nebulae. His mother, Anna, was the daughter of the governor of Connecticut and his father, William F. Keeler, was a paymaster in the U.S. Navy. Keeler attended high school until his family moved to Florida and then pursued no higher education for a while. He eventually attended John Hopkins University and served as an assistant to physicist, Charles Hastings. He eventually ended up in Allegheny, where he became the first professional astronomer to reside on Mount Hamilton. Here he used a 36 inch refracting telescope equipped with a spectroscope to measure wavelengths of the very bright spectral lines of nebulae. With this data he was able to tell if they were blue shifted or red shifted and therefore able to tell if they were moving towards or away from the Earth. He also discovered wavelengths that didn’t correspond to any transitions that had been observed on Earth. This lead to the idea that nebulae were comprised of something that wasn’t present on Earth, however this turned out to be incorrect as it was the combination of the motion of the atoms and the filtering effects of the nebulae that caused these lines. Shortly after this discovery he married Cora Slocomb Matthews only to take a journey back to Allegheny observatory. Once here he designed his own spectrograph, which allowed pictures to be taken of the spectral lines instead of simply looking at them through a telescope. This invention allowed the spectral lines of stars to be recorded and saved for later times and also to be analyzed much more effectively than they could have with a spectroscope. An example of how much more effective this new invention was is how Keeler used it shortly after its conception. He used was able to obtain proof that the theoretical prediction of James Maxwell that the rings of Saturn were meteoric in nature was correct. Another major discovery of Keeler was the how the number of spiral nebulae, which later turned out to be other galaxies, outnumbered the quantities of any other hazy object in the night sky. He was attempting to design a slitless spectrograph that could be used in conjunction with the 36 inch telescope when he suffered a heart and died at the age of 42 on August 12, 1900. Despite his relatively short life, Keeler was able to make many contributions to modern day astronomy that greatly changed how the universe is viewed.

APOD 3.5

Today I chose to write about the Rosette Nebula because it of how it looks and because it was on today's constellation quiz. It is located in Monoceros about 5,000 light years away and is an emission nebula with an open cluster of stars at its center. This open cluster of stars releases light from all across the electromagnetic spectrum. This light then hits the nebula and is essentially filtered out, certain wave lengths are absorbed and re-emitted in different directions whereas other wavelengths can go through unimpeded. This means that some colors show up brighter than others and the result is this stunning nebula that can be seen relatively easily.

Quarter 3 Astronomer Sources - James Keeler

1. "Keeler, James Edward." Complete Dictionary of Scientific Biography. Vol. 7. Detroit: Charles Scribner's Sons, 2008. 270-271. Gale Virtual Reference Library. Web. 18 Feb. 2011.

2. "Keeler, James Edward (1857-1900)." The Worlds of David Darling. Web. 18 Feb. 2011. <http://www.daviddarling.info/encyclopedia/K/Keeler.html>.

APOD 3.4

I chose to write about the iridescent clouds as seen from the World Highway in Yukon Territory, Canada. These clouds are formed usually around sunrise or sunset. The increased amount of atmosphere that the light must travel through causes the light to get bent. The blue light is scattered the most because it has the shortest wavelength and so it is not seen in this picture. The red end of the visible light spectrum however is scattered very little and manages to travel through the atmosphere almost unimpeded. The end result of this are clouds that have a very reddish or pinkish tint to them. Not only is this is a very astounding meteorological effect but it also looks very amazing, which is why I chose to write about it.

APOD 3.3

This is a picture of the star Zeta Ophiuchi as it pushes through dust and the interstellar medium. I chose to write about this picture for several reasons, the first being that it is relevant to the material being covered in class. Some of the particles that can be seen on the front of Zeta Oph are from the interstellar medium. While not appreciable by themselves, the motion of this star has brought them closer together and in doing so has made them much more visible. Another reason I chose to write about this picture is because of what is occurring in it. In this picture a star that is 20 times more massive than our own Sun is moving at 24 kilometers per second. The force necessary to bring a star of this mass to this speed is extremely high, but the fact that it has occurred is simply astounding and is why I chose to write about this picture.