APOD 2.1

This week I chose to write about the Andromeda Galaxy in ultraviolet and visible light. In this picture it is very easy to see the applications of other wavelengths of light outside of the visible spectrum. Ultraviolet, as can easily be seen here, penetrates cosmic dust and other impediments much easier than visible light. This give us a much clearer view of the object that is being looked at and also provides information that visible light simply cannot tell us. One example of this information is the fact that only hotter stars will be seen because they in order to radiate in the ultraviolet spectrum, they must be extremely hot. This is useful because many stars do not radiate only in the visible spectrum, which means all the possible data they give off can not be picked up by using visible light, which is why studying other wavelengths is helpful.

Observation 10/24/10

Tonight at about 9:10 I saw the Summer Triangle, which consists of Cygnus the Swan, Aquila the Eagle, and Lyra the Harp at slightly to the west of the zenith point. The moon was also very large in the Northeast at about 30 degrees above the horizon and it was in its waning gibbous phase, but it appeared to almost be a full moon. I also saw a very bright star about about 50 degrees above the horizon in the Southwest, but I wasn't able to identify it.

APOD 1.8

Today I chose to write about NGC 2683 because what it is. Many of the pictures are often of stars or other celestial objects that are in our own galaxy. However, this picture shows an entirely different galaxy from our own, one that is 20 million light years away. This distance has no meaning to people, as distances such as this, or anywhere close to this, are never encountered in a human life. It is also amazing that the galaxy that is seen in this picture is 20 million years old and that it could have completely changed and we would have no idea about it until 20 million years later. This is why I chose to write about NGC 2683.

APOD 1.7

This week I chose to write about the Globular Star Cluster NGC 6934. I chose this picture because of the vast span of it. This star cluster is about 50,000 light years away, which is far, but not as far as many of the other astronomical objects that we study. However, it is not this that astounds me, but it is the physical range of the picture. This picture spans 50 light years from side to side. This is so amazing to think about, the fact that we can view an area of the sky in such high resolution that is 50 light years across. This distance is ridiculously large and this is why I chose to write about this picture.

Quarter 1 Biography: Ole Roemer

Ole Roemer

            Ole Roemer was born in Aaruh, Denmark on September 25^th , 1644 and died in Copenhagen, Denmark on September 19^th 1710. Most of his adult life was spent in Copenhagen where he held a multitude of jobs, including astronomer royal, director of the observatory, master of the mint, inspector of naval architecture, harbor surveyor, ballistics expert, professor of mathematics at the University of Copenhagen, and the head of a commission which inspected highways. Despite all of these very prestigious jobs, he is best known for making the first accurate estimation of the speed of light. At this time in history very few astronomers even believed that there was a finite speed that light travelled at, most simply believed that it was instantaneous. Roemer was able to accurately determine the speed of light through very careful measurements over long periods of time. Roemer had his own observatory, the Tusculaneum, built between Copenhagen and Roskilde, which he filled with his own accurate instruments; he perfected the transit circle and is the first person to have attached a telescope to one. This observatory, in conjunction with the ground breaking instruments of that time allowed him to make very accurate observations of the heavens. He is alleged to have made just as many observations of Tyco Brahe, if not more. Roemer also had access to Brahe’s observations because he was appointed the editor of them by his brother Erasmus Bartholin. Brahe’s calculations were compounded by his own and with these 2 things Roemer was able to accurately calculate the speed of light, which was an amazing feat. The way that Roemer went about calculating the speed of light was through observations of the eclipses of Jupiter’s moons. He realized by looking at the observations of himself and Brahe that the eclipses either took place about 10 minutes earlier or later than they were predicted to, depending on the distance from the Earth to Jupiter. When Jupiter was closest to the Earth he noticed that they were about 10 minutes earlier than the calculations had predicted and while Jupiter was farthest away from the Earth he noticed that they occurred about 10 minutes later than they were predicted to. This led him to the realization that light had a finite speed, which few believed at that time. Because he now knew the difference in the time of the predictions that resulted because of the differing proximities of the Earth and Jupiter he was easily able to calculate the speed of light. His calculations stated that the speed of light was approximately 140,000 miles per second, which meant that the light coming from the Sun would take 11 minutes to reach the Earth. The current accepted speed of light is about 186,000 miles per second, or 8 minutes 20 seconds. This was an extremely close approximation for the first ever attempt at quantifying the speed of light and was clearly within an order of magnitude. The error that he experienced was caused by perturbations of Jupiter that he was unaware of at that time. Despite these findings, many people decided not to believe this fact and continued to believe that light had no finite speed. After this finding Roemer continued to do astronomical research along with his other multitude of jobs. Another creation that he isn’t famous for, but essentially designed is the thermometer. It was his idea to use the boiling point of water and the melting point of snow as the 2 base marks on a thermometer and it is alleged that he actually did more work on designing them than Fahrenheit did, but he is not known for this, which is why he is instead known as the person who first successfully approximated the speed of light.

APOD 1.6

I chose to write about the auroras over Alaska because they continue to fascinate me. In the picture it appears as if it is the middle of the day and that the auroras are actually clouds that are being lit up from the Sun's light. However, it is actually night and the auroras are adding the light that is seen in the picture. The fact that an aurora can add enough light to make it appear as if it was the middle of the day is a very astounding fact in and of itself, which is only compounded by the brilliant colors that are released from it. Also, due to the very long time exposure of the picture, the path of the stars in the sky can easily be seen. This not only is very pretty to look at, but it also helps to increase the understanding of the motion of the stars during the night because the circular paths that they travel in is very easy to see and helps visually explain why some stars are circumpolar and can always be seen.

Biographer Sources

My two sources for Ole Roemer's biography are:
Complete Dictionary of Scientific Biography. Vol. 11. Detroit: Charles Scribner's Sons, 2008. p525-527. 
and
http://www.amnh.org/education/resources/rfl/web/essaybooks/cosmic/p_roemer.html

APOD 1.4

Today I picked the Arp 188 and the Tadpole galaxy to write about because not only does it like astounding, but the dimensions that are involved in this picture are simply beyond comprehension. The largest object in this picture, which appears to be fairly close, is actually 420 million light years away. I cannot even fathom how far that is, because lengths of that quantity exist in very few places in the entire universe. It also astonishes me that the image of the galaxy that we see from earth is actually 420 million years old, and that it has more than likely substantially changed in the time that has passed. These facts just amaze me, which is why I chose to write about this picture.