Name________________________A Tale of Two SupernovaeMAT 1475 Project Part III (Dr. Miller)Please follow all direction carefully.You are, quite literally, made of stardust. The Big Bang created only Hydrogen and Helium; all other elements are created inside of stars by nuclear fusion. This includes Oxygen, Carbon, Calciumevery element aside from hydrogen and helium. When our sun dies it will swell in size, become a nebula, and gently fade away, keeping all of the elements it produces nearby. Some stars, a very special few, die in a spectacular explosion, propelling the elements created within the star and even heavier ones created during the explosion throughout their own galaxy and beyond. It is these stars that make life possible. It is these explosions, called supernovae, that can sometimes be seen from Earth and appear as visiting stars.1 When such stars explode, they shine up to 100 billion times brighter than normal, often brighter than all the other stars in their galaxy combined.

Tychos Star was not the first visiting star observed by humans on Earth. Quite a few were observed in Asia, the most famous of which is located in the Crab Nebula. In the location of an event observed in the sky in 1054 Common Era (a visiting star) modern day physicists found in 1967 traces of unexplained astral phenomena. Specifically, in a survey of the sky, a University of Cambridge team found regular electromagnetic pulses coming from apparently nowhere. Generally the electromagnetic signals from the sky are what is called `noise: we cant distinguish any particular patterned signal (although a lot of people look! If you want an easy way to be part of the search for extraterrestrial life, read the footnote!2 SETI, the Search for Extra-terrestrial Intelligence, analyzes as many of the signals coming to Earth from space as possible, many of them using the home computers of volunteers. If you like, you can download a program that analyzes signals on your computer when you are not using it, and then sends the results to SETI. See: www.seti.org for information about SETI and http://setiathome.ssl.berkeley.edu/ to be part of their effort to find life in the universe.

). I invite you to think of everything you can that has a pattern. What percentage of them are caused by a life-form?These pulses were not just noise. For over a month, the Cambridge team continued to monitor the pulses. Here is what Nobel Prize winner3 It was actually his graduate student, Jocelyn Bell, who made the initial discovery. There are some who feel she should have been a co-recipient of the prize.

Antony Hewish said about the period of watching and wondering in his 1974 Nobel Prize acceptance speech.Having found no satisfactory explanation for the pulses we now began to believe that they could only be generated by some source far beyond the solar system, and the short duration of each pulse suggested that the radiator could not be larger than a small planet. We had to face the possibility that the signals were, indeed, generated on a planet circling some distant star, and that they were artificial.He goes on to say Without doubt, those weeks in December 1967 were the most exciting in my life. For a while, they called the phenomena LGM4 Little Green Men

(guess before you read the footnote!). Ultimately they found that LGM were not responsible for the pulses. The cause of the pulses was the remnant of a supernovathe explosion of a giant star threw away all the material in the outer layers of the star and left only the core, a mass so dense that the protons and electrons were crushed together to become neutrons. This rapidly spinning mass is a neutron star, or pulsar, and the gravitational field on a neutron star is about times that on Earth. (This means you would weight 200 billion times as much as you do on Earth. Before the discovery of the first pulsar by Hewish and his team, neutron stars were hypothetical stellar entities. It is the explosions (supernovae) that we can often see from Earth, even with the naked eye. Pulsars a quite smallsmaller than Brooklynand are observed through the radio waves they emit, not though light in the visual field.Because pulsars spin so rapidly and because they have such a strong gravitational field, they emit electromagnetic radiation at their poles in the form of radio waves. Visible light is also a form of electromagnetic radiation, but with a much shorter wavelength. The length of radio waves are between a decimeter and a kilometerso they have length approximately from the size of a kitten to the size of a very tall building. Visual light, on the other hand, has a wavelength around the size of the average (microscopic) bacteria. The spinning of the pulsar is like the revolving light in a lighthouse: each time a pulsar with a pole that points toward earth rotates, we see a pulse of electromagnetic radiation, a radio wave. Pulsars are very consistent in the intervals of their rotation, which makes them excellent clocks.Pulsars are still being discovered and actively studied, both by professional astronomers and by amateur astronomers. (See the references for how you can help to find new pulsars.)It is precisely explosions like the spectacular death of the star witnessed by Tycho Brahe that are responsible for the formation and dissemination of the elements required for the sustenance of life in the universe. Take a five undistracted minutes and reflect on this cosmic wonder. The equivalent of one paragraph describe your thoughts or feelings about the fact that you are composed of stars. This can be prose, poetry, a story, a dialogue, a drawing, whatever you like (provided it addressing your thoughts or feelings on the above). (15 points)

(45 points)

One Step Ahead213 Corner DriveQueens, NY 1137817 April, 2014

Mathematics DepartmentNew York City College of Technology300 Jay StreetBrooklyn, NY 11201

Dear Calculus Students:Allow me to introduce myself. My name is Morgan, and I just got my first "real'' job at One Step Ahead. It's pretty exciting for me; the job has benefits and everything. That is why I'm writing to you. While I'm pretty good at what I do, I always feel insecure when it come to math, and I'd like to be sure I make a good decision for myself and my future. Your professor told me that you are highly capable, professional, and reliable, and suggested that I ask you to help me provide an answer to a question. Here's the situation. The Crab pulsar was observed on Earth in 1054 CE.

Tychos Star was first observed on Earth in 1572 CE.

The Crab pulsar (SN 1054) is between 4,800 lightyears and 8,200 lightyears away.

Tychos pular (SN 1572) is between 10,000 lightyears and 16,000 lightyears away.

My bosses want to know an interval for the likely Earth-time explosions of each star and compare the intervals. Keep in mind that a lightyear is a unit of distance. It is the distance light can travel in one year: 300,000 kilometers or 186,000 miles. One kilolightyear (kly) is one thousand light years (ly).Kindly determine whether the Crab pulsar or Tychos pulsar was formed first (in other words, which supernova explosion occurred first). Use the information above to make your determination. Write a memo to me of no more than one page that provides: (1) a statement of the problem, (2) your solution to the problem, and (3) your support for your solution. (Give the intervals for each supernova in Earth years.) If you omit any of the three items above, I will be unable to give a satisfactory answer to my bosses.

To reiterate: we dont know the exact distances from Earth to the Crab pulsar or from Earth to Tychos pulsar, so your Earth time dates of these explosions should be intervals, not exact dates. Then you will compare intervals. To find when the supernovae took place you will have to use the fact that light travels one lightyear in a year. My bosses told me to remember: If a bird flies two lightyears at the speed of light, how long does it take the bird to travel that distance? Please spell it all out for me, using plain English to explain the equations you use and support to justify your conclusions. If you use any other sources, please be sure to tell me about them. Your professor said it's fine if you work in teams of no more than three and submit one letter per team.I have to make my report by 7 May, so please give your professor a hard copy of your report no later than that date. Earlier is even better.Thanks so much in advance. I look forward to reading your memos.Cordially, Cornelius ThatcherPS: Further ReadingAntony Hewish, Pulsars and High Density Physics. Nobel Lecture, December 12, 1974. (This is Hewishs account of finding the first pulsar.)

Searching for and Identifying Pulsars. University of Virginia. http://www.astro.virginia.edu/~rsl4v/PSC/light.html

(This is a great way to read more about and even be part of the ongoing search for pulsars.)