Space: The Final Frontier

 

Space

The Final Frontier

 

By David K. Ewen, M.Ed.  

 

ISBN: 9798677880025

Imprint: Ewen Prime Company

 

Copyright (c) 2020, Ewen Prime Company

 

All rights reserved. No part of this publication may be reproduced, distributed, or transmitted in any form or by any means, including photocopying, recording, or other electronic or mechanical methods, without the prior written permission of the publisher, except in the case of brief quotations embodied in critical reviews and certain other noncommercial uses permitted by copyright law. For permission requests, write to the publisher, addressed “Attention: Permissions Coordinator,” at the address PAASEinst@gmail.com

 

  

Content

 

1.    In memory

2.    Extract

3.    Dedication & Thanks

4.    Purpose

5.    Premise

6.    Prologue

7.    Introduction

8.    When It Happened

9.    Beyond Harvard University

10.  Early years of Edward M. Purcell, Ph.D.

11.  Early years of Harold “Doc” Ewen, Ph.D.

12.  Detection of Hydrogen

13.  Aftermath of Accomplishment

14.  A New Understanding

15.  The 70th Anniversary

16.  Awards Presented

17. Bibliography

 

 

In memory ….

 

In cherished memory of my Dad, Harold “Doc” Ewen, Ph.D. who reached to the final frontier and to Mary Ann Ewen who was my Dad’s greatest supporter, loving wife, and adoring mother of eight children.

 

Extract

 

On March 25th, 1951, the very first detection of hydrogen using a radio telescope with a horn antenna sticking out of a window on the 4th floor of the Lyman Physics laboratory at Harvard University was accomplished.  This capability is the foundation of further discoveries allowing us to see the universe in a way never possible before.  In 1951, on the 4th floor of the Lyman Laboratory, Harold "Doc" Ewen, Ph.D. was the first to observe and detect neutral hydrogen.  His Harvard University thesis advisor was Edward, M. Purcell, Ph.D.  This day made history in scientific space exploration.   Harold “Doc” Ewen was my father and I share "his story" which is "history".   I deeply am humbled and honored to work with Harvard University, the National Radio Astronomy Observatory, and the Green Bank Observatory to serve as a representative of early space exploration in sharing history related to my father's work in 1951.  Thank you.

 

Dedication & Thanks

 

Harvard University (Physics)

https://www.physics.harvard.edu/

 

Harvard University (Astronomy)

https://astronomy.fas.harvard.edu/

 

Center for Astrophysics

(Harvard University & Smithsonian Institution)

https://www.cfa.harvard.edu/

 

National Radio Astronomy Observatory

https://public.nrao.edu/

 

Green Bank Observatory:

https://greenbankobservatory.org/

 

Associated Universities, Inc.

https://aui.edu/

 

National Science Foundation.

https://www.nsf.gov/

 

 

 

Purpose

 

The purpose of this content is to explain in layman's terms the start of true space exploration of our universe. The layperson on the street considers space exploration involving a rocket. The complexities of space exploration using radio telescopes was beyond my comfort level when my father tried to explain it to me when I was a little boy.

 

The year 1951 is significant in terms of the events associated with the space exploration topic that I am to discuss related to my father's Ph.D. doctoral work at Harvard University with his thesis advisor Edward M. Purcell.  Specifically, it is the detection of neutral hydrogen in interstellar space within the Milky Way galaxy. Detection of a specific radio frequency in space allows scientists to create pictures of celestial bodies in our universe that cannot be seen with a traditional optical telescope. 

 

On March 25, 1951 the very first detection of hydrogen using a radio telescope with a horn antenna sticking out of a window on the 4th floor of the Lyman Physics laboratory at Harvard University was accomplished. This capability is the foundation of further discoveries allowing us to see the universe in a way never possible before. In a television interview, it was explained that my father, Harold "Doc" Ewen, Ph.D. called his thesis advisor Edward M Purcell, Ph.D. in the early Easter morning hours in 1951 and said, "I have a thesis". 

 

I was born in a time after man went into space but before he walked on the moon. My infancy was in the midst of the dawn of humans physically reaching other celestial bodies near our planet. It was an exciting time. The media could easily explain it because it was something you could physically see.

 

Before I was born, space exploration involved exploring the universe and observing things you could not see.  This involves the use of radio telescopes.  Even while I was in elementary school, the appreciation of the kind of space exploration that occurred in the early 1950s could not be realized. I much rather prefer knowing more about the Rockets going to the Moon at that time as a young boy. The idea of using radio was not something clearly understood. That would in turn help us. The structure of the Spiral arms of the Milky Way galaxy did not interest me.

 

As an older, more mature and educated adult, I can now understand and recognize the significance of how radio telescopes were instrumental in the early advances of space exploration.   My responsibility here is to present this understanding in a way that a non-scientist, such as myself, can understand that true exploration began years before NASA.  I take it as a responsibility to reveal the historical significance of space exploration specifically in the year 1951. That was twelve years before I was born. When I was born a pictorial understanding of what the universe look like was better understood then before and that is the world that I grew up in.

 

While working with representatives at Harvard University and the National Radio Astronomy Observatory, I have been able to compile the pieces of history along with my own records to create a simple non-technical introduction to the significance of space exploration as it occurred in 1951. I have also included other pieces of history so that the events that occurred in 1951 can be put in the proper timeline.

 

What is presented here has been reported and recorded elsewhere, but not compiled collectively in simple to understand terms for the non-scientific community. That is where I come in. I grew up in a time when space exploration became a passion of excitement. My father, Harold “Doc” Ewen, was an obvious integral part of the events that occurred in 1951 that I will discuss. As an educator since 1988 and a public speaker since 1998, I'm fit to present a summary of scientific events in a non-scientific way for the general community. My hope is that what I present gives passionate excitement to the understanding of space exploration that began in 1951.

 

It should be noted that the historical references and timelines within this content are presented at a basic level. There is so much more that can be added, but my intent is to simplify the understanding so that the specific event in 1951 can be more easily understood.   This content was produced in preparation for the 70th anniversary of the detection of hydrogen at Harvard University. That is why the events that occurred on March 25th, 1951 have the greatest focus of attention.

 

During my studies of the historical understanding and significance of the detection of neutral hydrogen at Harvard University on Sunday March 25th 1951, I find great appreciation to Harvard University, the National Radio Astronomy Observatory, and the Green Bank Observatory for their continued science contributions to exploration of space.   Please allow my small presentation to be a small part of recognizing history as understood for the events in 1951. I know that if my father, who was an integral part of the events that occurred in 1951, were still here, he would know all the names and organizations to give a deep heartfelt appreciation and thanks for making his efforts possible and all future efforts possible.  

 

 

Premise

 

The field of radio astronomy is the study of celestial objects at radio frequencies.  Optical astronomy allows us to see objects such as stars and galaxies that emit a lot of visible light.  When electrons and protons within atoms accelerate by changing their speed or direction, they emit electromagnetic radiation.  We can detect many forms of electromagnetic radiation using a radio telescope.  The gas found in interstellar space emits radio waves at distinct wavelengths.   Hydrogen is the most abundant element in the Universe. Astronomers use Hydrogen's characteristic emission at 21 cm to map out the structure of galaxies. 

 

This ability to detect neutral hydrogen first occurred on Sunday, March 25, 1951 by Harold "Doc" Ewen at Harvard University working on his Ph.D. thesis.  He immediately called his advisor, Edward M. Purcell, and said, "I have a thesis".    His Ph.D. thesis titled, "Radiation from Galactic Hydrogen at 1420 Megacycles per Second" reported on the first detection of a spectral line in radio astronomy in collaboration with his advisor, Edward M. Purcell, Ph.D. 

 

 

Since that time, radio astronomy has detected many new types of objects including pulsars and quasars.  We can see a universe that radiates at wavelengths and frequencies we can’t see with our eyes.  Objects in the universe give off unique patterns of radio emissions.  Different wavelengths are generated by different objects and radio astronomers use a variety of methods and instruments to detect them.  The radio signals detected by radio telescopes are converted into data that can be used to make images.  For example, they are used to measure clouds of gas, which are abundant in the spiral arms of the Milky Way Galaxy making  it possible to map the galaxy’s overall layout. Today, new radio telescopes provide ever more detailed views of the Milky Way.

Prologue

 

An American, Karl Guthe Jansky, was a physicist who first discovered radio waves emanating from the Milky Way in the early 1930s while working for Bell Telephone Laboratories in New Jersey. Today, in recognition of Jansky, the Jansky Lab building is at Green Bank Observatory in Green Bank West Virginia.

 

Hendrik C. van de Hulst predicted the existence of the 21 cm hyperfine line of neutral interstellar hydrogen in 1944 while a student in Utrecht, Netherlands.

 

Theodore Lyman was the first director of the Research Laboratory of Physics at Harvard University. In 1947, the lab was renamed the Lyman Laboratory of Physics. 

 

In 1951, on the 4th floor of the Lyman Laboratory, Harold "Doc" Ewen, Ph.D was the first to observe and detect neutral hydrogen.  His Harvard University thesis advisor was Edward, M. Purcell, Ph.D who shared the 1952 Nobel Prize in Physics for the discovery of nuclear magnetic resonance in liquids and in solids.

Hydrogen is the most common element in the universe and emits a specific energy at a specific frequency.  The microwaves of the hydrogen line come from the atomic transition of an electron between the two hyperfine levels of the hydrogen called the spin-flip transition emitting a specific photon corresponding frequency of 1420 MHz (just above the TV and cellphone bands). It is called the 21-centimeter line which is the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms. The wavelength is 21 cm.

 

During the period 1952-1958, Harold "Doc" Ewen, Ph.D. was Co-Director of Harvard University. Radio Astronomy Program.  He was a member of the committees that recommended establishment of a national facility for radio astronomy (through the National Science Foundation), and also recommended Green Bank, West Virginia, as the best site for the National Radio Astronomy Observatory.

 

 

Around 1956 Associated Universities, Inc (AUI) was contracted by the National Science Foundation to begin the development and building of NRAO.  On October 17, 1957, the groundbreaking and dedication of the Green Bank location was held.  In the 1960's the NRAO moved its headquarters from Green Bank to the University of Virginia campus in Charlottesville, Virginia. 

 

Green Bank Observatory remains in West Virginia on 155 Observatory Rd in Green Bank, West Virginia.  The horn antenna used for the first detection of the 21 cm emission from neutral hydrogen in the Milky Way is now displayed in front of the Jansky Lab at the Green Bank Observatory in Green Bank, West Virginia.

 

 

Introduction

 

It was in 1903 that the world started the journey to leave the grasps of Earth's gravity. Wilbur and Orville Wright's first powered flight on December 17, 1903 and demonstrated the world's first sustained flight of a heavier-than-air machine under the complete control of the pilot.  The first flight lasted just 12 seconds with Orville piloting the craft.  Wilbur flew for 59 seconds on the fourth and final flight of the day.  The United States Army purchased flying machines in 1908.  The air force was established 2 years after World War II on September 18, 1947.  It was a time people reached for the sky before going into space.  The stars were next.

 

On October 4, 1957, 7:28 PM, the Soviet Union launched the first artificial satellite, Sputnik 1 into space and entered orbit.  The National Aeronautics and Space Administration (NASA) began in 1958 to launch vehicles for America's civilian space efforts. On April 12, 1961, Soviet Cosmonaut Yuri Gagarin was the first human in space aboard Vostok 1.  Project Mercury was the United States' first man-in-space program from 1958 to 1963.  NASA's second human spaceflight program was Gemini that started in 1961 and concluded in 1966.  John F. Kennedy made a lunar landing a national priority.  On September 12, 1962, he presented his famous, "We choose to go to the Moon" speech on the Nation's Space Effort. Project Apollo was the third United States human spaceflight program succeeded in landing the first humans on the Moon from 1969 to 1972.

 

The definition of space exploration for most people involves the understanding of what happened in the early 1960s when man left soil and went into space. In the following decade, space exploration involved walking on the moon. We typically think of space exploration in terms of satellites and Rockets.

 

 

Space Exploration Before Rockets

 

As a young boy, the space exploration that I became aware of is what my father taught me from his experience at Harvard University in the early 1950s. Using a radio telescope, he was able to detect neutral hydrogen in the Milky Way galaxy for his doctor thesis at Harvard University in 1951. This capability created the foundation of being able to map celestial bodies such as galaxies in our universe. This meant that we were able to see beyond our solar system what existed.  We got a sense of what the universe looks like realistically.

 

The excitement of space exploration filled my childhood experiences with TV shows like Star Trek and movies like Star Wars. In conjunction with Americans walking on the moon, the excitement of space exploration never left me. I do recognize however that the earliest form of space exploration was succeeded on March 25, 1951 on the fourth floor of the Lyman Physics Laboratory at Harvard University by my father, Harold "Doc" Ewen, Ph.D.  He was assisted by his doctoral thesis advisor Edward M. Purcell, Ph.D.

 

Space is truly the final frontier. The work done 1951 began that Journey. Before satellites in man could travel into space, we needed to know what was up there and beyond.  It was important because we had to know what we were reaching for.  The work done at Harvard University gave the opportunity to pave the way for further space exploration in many different ways.

 

The horn that was used in 1951 as the radio telescope antenna at Harvard University sits proudly in front of the Green Bank Observatory in West Virginia today. It is a strong reminder of the beginning of deep space and interstellar space exploration.

 

I write this in the year before the 70th anniversary of the first detection of neutral hydrogen in space. As the son of Doc Ewen, I am humbled and honored to work with Harvard University, the National Radio Astronomy Observatory, and the Green Bank Observatory to serve as a representative of early space exploration. A Consortium of astronomers, physicists, space Explorers have been invited in celebration with the P.A.A.C.E. Institute https://about.me/paase

 

 

My dad was an adventurous space explorer.  About seven years before NASA was established, my father was the epitome of the excitement of observing the stars and universe.  Before the first satellite was launched in 1957, humans traveling in space in 1961, and Americans walking on the moon in 1969, deep space exploration began in 1951 at Harvard University.  My father, Harold "Doc" Ewen and his thesis advisor Ed Purcell were the first to detect neutral hydrogen in the milky way galaxy. Radio telescopes were used to study interstellar molecular gas clouds. The technique was used to map large-scale matter distribution in the galaxy successfully allowing for true exploration of space. It was used to define the spiral arms of the Milky Way Galaxy and to determine the rotation of the Galaxy.  That’s how we get to truly see what the Milky Way and other galaxies look like.   The work of my father at Harvard University along with his thesis advisor allowed us to see what the universe looks like beyond our solar system.  That is true space exploration.  This is where it all started in terms of large-scale exploration of our universe.  Space really is the final frontier. 

 

 

When It Happened

 

The 25th of March, 1951 (Easter Sunday), marked the date when Harold Doc Ewen and Edward M. Purcell succeeded with the first detection of radio radiation from neutral atomic hydrogen gas in the milky way at a wavelength of 21 centimeters at Harvard University. Thursday, March 25 2021 is the 70th anniversary since this discovery was first made.  This date is nearly 3 weeks after what would have been Doc Ewen’s 99th birthday.

 

 

Ewen and Purcell

 

Harold Irving Ewen was born on the 5th of March 1922 in Chicopee, MA. He graduated in Mathematics and Astronomy from Amherst College in 1943 and earned his MA in 1948. He would later join Harvard University where he received his M.A in 1948 and PhD in Physics in the year 1951. He has won awards like the IEEE Morris E. Leeds Awards.

 

While studying at Harvard University, Ewen worked to design and build an apparatus for the new cyclotron 40 hours a week. At the same time, his nights and weekends were spent working towards his doctorate completion by building a receiver that would detect the 21cm line of neutral hydrogen in space. Edward Purcell was Ewen’s supervisor for the doctorate thesis, “Radiation from Galactic Hydrogen at 1420 Megacycles per Second”.

 

Professor Ed Purcell would stimulate Dr. Ewen’s measurements career in passive microwave remote sensing and worked together to detect the 21 cm interstellar hydrogen radiation successfully. After this discovery, in 1952, Dr. Harold I. Ewen was a co-director of the Harvard University Radio Astronomy Program from 1952 to 1958.  Doc Ewen was a member of various committees that came up with the recommendations to establish a national facility for radio astronomy through the National Science Foundation, recommending Green Bank, West Virginia, as the most appropriate site for it. Ed Purcell won the Nobel Prize in Physics in the year 1952.

 

 

Beyond Harvard University

 

Together with Professor Bart J. Bok, Dr. Ewen started organizing and teaching radio astronomy in the first graduate course at Harvard University. The course needed a radio telescope, and upon colleague suggestions, Dr. Ewen formed a company whose purpose was to assemble the telescope, though the company would later be dissolved, and Ewen returned to teaching at Harvard University. His contributions are in the passive microwave measurement performance, as well as developing new techniques for measurement.

 

Doc's interest in radio properties began with the interstellar space of natural phenomena in the 1950s, then the sun, moon, and planets in the 1960s. He participated in the performance measurements meant to determine useful applications that passive microwave sensors had in the satellites that orbit the earth. His research on precise measurements was intended to evaluate analytical predictions while developing better prediction models empirically.

 

 

Early years of Edward M. Purcell, Ph.D.

 

Born on the 30th of August 1912, in Taylorville, IL, Edward M. Purcell was a Purdue university electrical engineering graduate class of 1933. He later joined Harvard University and earned a Ph.D. in Physics in 1938. Purcell was a physics instructor for two years at Harvard University. He then went on to spend World War II years working on microwave radar research at MIT Radiation Laboratory in Massachusetts, where he headed the Fundamental Developments Group.

 

Following World War  II in 1949, Purcell went back to Harvard as an Associate Professor of physics. He led hydrogen observation as Doc Ewen's supervisor who was working on his doctoral thesis to detect radio emissions from galactic hydrogen, an observation that helped launch the radio astronomy field into what it is today. Ed Purcell continued to work in nuclear magnetism touching on problems related to atomic constants measurement, molecular structure, and nuclear magnetic behavior.

 

 

Early years of Harold “Doc” Ewen, Ph.D.

 

Doc Ewen was born in Chicopee, Massachusetts and grew up in East Springfield, Massachusetts born of a carpenter father. In his early years, he schooled at Tech High, Elliott Street., where he was a math major. After he turned 16, he moved to Amherst as he joined Amherst College, where his main interest was in math and had a hobby interest in asteroids and orbits of comets.

 

Initially, he joined Springfield College that had offered him a four-year scholarship, but since they did not study math-his area of interest, he had to decline the offer. He then moved on to Amherst College for his bachelor’s and Master’s degrees.

 

When Ewen graduated with a B.A in Mathematics and Astronomy at Amherst College, he made history as the youngest faculty member of the college at that time. His faculty colleagues in an informal ceremony awarded him the title "Doctors of Docs Degree," hence the nickname "Doc." For one year, Doc Ewen taught at Amherst before serving at World War II as a Naval officer.

 

 

 

Detection of Hydrogen

 

In his original paper, predicting the existence of the 21 cm line, Hendrik C. van de Hulst expressed doubt that the line of neutral hydrogen would be detectable. However, the 1948 paper by Shklovski showed more optimism, which made Ewen and Purcell feel like the Russians would work on detecting the line faster than the Dutch would. Therefore, they decided to make a sensitive detection attempt even though the experiment had a high likelihood of yielding a negative result.  The chances of success seemed low.

 

The experiment would require some funding for materials necessary to set it up. So, Ewen's supervisor Purcell sought a $500 grant from the Rumford Fund of the American Academy of Arts and Sciences, which was granted. The entire amount would go towards acquiring materials needed to build the antenna, waveguide, and electronic components.

 

With the materials acquired, Harold “Doc” Ewen designed the horn antenna, mixer, and receiver, in consultation with the field experts. Bob Pound would help him with the mixers, while Sam Silver guided him with the antenna design. The receiver was designed to cancel out background noise through a novel technique to switch frequencies, which was used in astronomy at the time.

 

 

This project took Doc Ewen a whole year to set up since he only worked on it during the night and over the weekends. Once he had completed building the horn antenna, he placed it outside a fourth-floor window of the Lyman Laboratory of Physics at Harvard University. The waveguide led to the receiver and recorder through the window. There were some hazards that came with the project, like the flooding of the rain over the rainy season as the antenna's horn would act as a funnel, and the students also saw the horn as their snowball’s target over winter. Overall, the experiment became a success!

 

After the first detection of radio radiation from neutral atomic hydrogen gas in the milky way at a wavelength of 21 centimeters, Ewen would meet and talk to Hendrik C. van de Hulst about his discovery at Purcell’s suggestion. At the time, Hulst was spending the spring term teaching a course at Harvard University. The Dutch Group would adopt his frequency switching technique and succeed in detecting the line on the 11th of May.

 

 

Aftermath of Accomplishment

 

Ewen and Purcell's accomplishment shows that science does depend on borrowed technology at times, not necessarily developed with a scientific need. The two had an unusual combination of scientific and engineering knowledge, as well as critical hardware and technical assistance in the years 1950 and 1951, giving them a competitive edge over all other groups undertaking similar research. Ewen and Purcell used the "small-science" style to deliver some groundbreaking scientific work.

 

Kerr Frank, an Australian astronomer who happened to be in Harvard University that year for a fellowship, heard about the Ewen-Purcell discovery and wrote to J.L Pawsey describing it. The Pawsey radio physics group would then build a frequency switching frequency and detect the line on the 12th of July. These results and the Dutch were published in the Nature issue of 1951, with the Australian results later published fully in the Australian J. Sci. Res.

 

 

Numerous astronomers, mainly from Dutch, Australia, and America, would later observe the neutral line with more accuracy. This technique was used to map large-scale matter distribution in the galaxy successfully. Today, the Ewen-Purcell horn antenna is displayed at the Lyman Laboratory of Physics at Harvard University and in front of the Jansky Lab at NRAO, Green Bank Observatory, West Virginia.

 

 

 

 

A New Understanding

 

The discovery of radio radiation from neutral atomic hydrogen gas in the milky way at a wavelength of 21 centimeters using the Ewen-Purcell Horn Antenna is to date, an essential aspect of radio astronomy. It brought about a detailed understanding of the galaxy's interstellar medium and in the external galaxy studies. Engineer Karl Jansky discovered radio astronomy in 1933 and found out that radio waves came from not only inventions, but also natural stuff found in space.

 

The 21-centimeter line is an electromagnetic radiation spectral line, created when the energy state changes in neutral hydrogen atoms. The electromagnetic radiation frequency is 1,420,405,751.7667±0.0009 Hz, equivalent to 21.1061140542 cm vacuum wavelength in free space.

 

With the assumption that there is a uniform distribution of hydrogen atoms throughout the galaxy, every line of sight reveals a line of hydrogen that is only different on their Doppler shift, making the calculation of each arm's relative speed of the galaxy. Our galaxy's rotation curve is calculated using this 21cm line of hydrogen, and with the rotation curve plot and velocity, determination of the distance to galaxy points is possible.

 

 

Radio protons are what the radio astronomers use to learn more about the hidden universe. These protons travel in waves, using the same pieces of tracks over and over again. The size of the wave made by the protons is what is called wavelength, and its length determines its energy. Radio waves have small frequencies and longer wavelengths, where a long wave has less energy, and a short one has a lot of it. Karl Jansky was the 1st radio astronomer.

 

In radio astronomy, radio waves that are in the electromagnetic spectrum, and radio astronomers use radio waves to see through all the large clouds of dust and darkness, to show even how gases swirl around Neptune and Uranus. Interstellar clouds of atoms and molecules collapse under the force of gravity they become stars, and a radio telescope helps us learn about them more by showing us those stars near us. Also, if you want to see some weird objects in the universe and even solve some mysteries, use radio telescopes.

 

The discovery solved the challenge of low resolution, preventing the early researchers from determining where solar radio emission sources were positioned and determining radiation distribution across the sun's disk. Scientists can use radio telescopes to detect new planets, new and dying stars, black holes, and many others that regular telescopes cannot detect.

 

 

 

 

The 70th Anniversary

 

The 70th-anniversary celebration of the first detection of the hydrogen gas in the milky way at a 21 centimeter wavelength in 1951 by Harold “Doc” Ewen and Prof. Edward M. Purcell, his thesis advisor at Harvard University, will be hosted by the P.A.A.S.E Institute https://about.me/paase (a consortium of Professional Astronomers, Astrophysicists, and Space Explorers) in partnership with Harvard University, the National Radio Astronomy Observatory, and Green Bank Observatory.

 

I deeply am humbled and honored to work with Harvard University, the National Radio Astronomy Observatory, and the Green Bank Observatory to serve as a representative of early space exploration in sharing history related to my father's work in 1951.  Thank you.

 

Awards Presented

 

I present awards in honored appreciation to Harvard University, National Radio Astronomy Observatory (NRAO), and Green Bank Observatory for continued space exploration from the P.A.A.S.E. Institute.

 

The P.A.A.S.E. Institute is a consortium of volunteers who are professionals in astronomy, astrophysics, and space exploration.  The institute was established to recognize and celebrate the 70th anniversary of the first detection of radio radiation from neutral atomic hydrogen gas in the Milky Way at a wavelength of 21 centimeter by Harold “Doc” Ewen, Ph.D. His doctoral thesis advisor at Harvard University was Edward M. Purcell, Ph.D.

 

 

 

 

 

Bibliography

 

●     https://www.gb.nrao.edu/fgdocs/HI21cm/ephorn.html

●     https://www.nrao.edu/archives/Ewen/ewen_top.shtml

●     https://ethw.org/Harold_I._Ewen

●     https://www.youtube.com/watch?v=Lw0aQ2v-CRs

●     https://www.aip.org/history-programs/niels-bohr-library/oral-histories/6659

●     https://www.cambly.com/en/student/tutors/54d62f5cf4afa50018458156#schedule