This image is a composite of several types of radiation astronomy: radio, infrared, visual, ultraviolet, soft and hard X-ray. Credit: NASA.

Radiation astronomy is astronomy applied to the various extraterrestrial sources of radiation, especially at night. It is also conducted above the Earth's atmosphere and at locations away from the Earth, by satellites and space probes, as a part of explorational (or exploratory) radiation astronomy.

Seeing the Sun and feeling the warmth of its rays is probably a student's first encounter with an astronomical radiation source. This will happen from a very early age, but a first understanding of the concepts of radiation may occur at a secondary educational level.

Radiation is all around us on top of the Earth's crust, regolith, and soil, where we live. The study of radiation, including radiation astronomy, usually intensifies at the university undergraduate level.

And, generally, radiation becomes hazardous, when a student embarks on graduate study.

Cautionary speculation may be introduced unexpectedly to stimulate the imagination and open a small crack in a few doors that may appear closed at present. As such, this learning resource incorporates some state-of-the-art results from the scholarly literature.

The laboratories of radiation astronomy are limited to the radiation observatories themselves and the computers and other instruments (sometimes off site) used to analyze the results.

Selected resource

Astronomy specifically focused at the microwave portion of the electromagnetic spectrum is microwave astronomy.

More resources...
Selected lecture

The image shows a chain of craters on Ganymede. Credit: Galileo Project, Brown University, JPL, NASA.

Def. a hemispherical pit a basinlike opening or mouth about which a cone is often built up any large roughly circular depression or hole is called a crater.

The image at right shows a chain of 13 craters (Enki Catena) on Ganymede measuring 161.3 km in length. "The Enki craters formed across the sharp boundary between areas of bright terrain and dark terrain, delimited by a thin trough running diagonally across the center of this image. The ejecta deposit surrounding the craters appears very bright on the bright terrain. Even though all the craters formed nearly simultaneously, it is difficult to discern any ejecta deposit on the dark terrain.

Selected theory

At the bottom of this visible emission model is a visual intensity curve. Credit: Stanlekub.

At its simplest theoretical radiation astronomy is the definition of terms to be applied to astronomical radiation phenomena.

Def. a theory of the science of the biological, chemical, physical, and logical laws (or principles) with respect to any natural radiation source in the sky especially at night is called theoretical radiation astronomy.

Exploratory theory is the playtime activity that leads to discoveries which better our world. In the radiation physics laboratories here on Earth, the emission, reflection, transmission, absorption, and fluorescence of radiation is studied and laws relative to sources are proven.

A principle is a law or rule that has to be, or usually is to be followed, or can be desirably followed, or is an inevitable consequence of something, such as the laws observed in nature or the way that a system is constructed. The principles of such a system are understood by its users as the essential characteristics of the system, or reflecting system's designed purpose, and the effective operation or use of which would be impossible if any one of the principles was to be ignored.[1]

Radiation astronomy consists of three fundamental parts:

1. derivation of logical laws with respect to incoming radiation,
2. natural radiation sources outside the Earth, and
3. the sky and associated realms with respect to radiation.

Def. a spontaneous emission of an α ray, β ray, or γ ray by the disintegration of an atomic nucleus is called radioactivity.[2]

### References

1. Guido Alpa (1994). "General Principles of Law". Annual Survey of International & Comparative Law 1: 1. Retrieved 2012-04-29.
2. Philip B. Gove, ed. (1963). Webster's Seventh New Collegiate Dictionary. Springfield, Massachusetts: G. & C. Merriam Company. p. 1221. |access-date= requires |url= (help)
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## Emissions

The Hubble Space Telescope [Advanced Camera for Surveys] ACS image has H-alpha emission of the Red Rectangle shown in blue. Credit: ESA/Hubble and NASA.

"[T]he extended red emission (ERE) [is] observed in many dusty astronomical environments, in particular, the diffuse interstellar medium of the Galaxy. ... silicon nanoparticles provide the best match to the spectrum and the efficiency requirement of the ERE."[1]

### References

1. Adolf N. Witt, Karl D. Gordon and Douglas G. Furton (July 1, 1998). "Silicon Nanoparticles: Source of Extended Red Emission?". The Astrophysical Journal Letters 501 (1): L111-5. doi:10.1086/311453. Retrieved 2013-07-30.
Objects
Selected image

X-ray photo is by the Chandra X-ray Observatory of the Bullet Cluster (two colliding galaxy clusters). Exposure time was 140 hours. The scale is shown in megaparsecs. Redshift (z) = 0.3, meaning its light has wavelengths stretched by a factor of 1.3. Credit: Mac_Davis.

Selected lesson

## First infrared source in Crux

This infrared image from NASA's Spitzer Space Telescope shows the nebula nicknamed "the Dragonfish". Credit: NASA/JPL-Caltech/Univ. of Toronto.

The first infrared source in Crux is unknown.

The field of infrared astronomy is the result of observations and theories about infrared, or infrared-ray sources detected in the sky above.

The first astronomical infrared source discovered may have been the Sun.

But, infrared rays from the Sun are intermingled with other colors so that the Sun may appear yellow-white rather than infrared.

The early use of sounding rockets and balloons to carry infrared, optical, or visual detectors high enough may have detected infrared-rays from the Sun as early as the 1940s.

This is a lesson in map reading, coordinate matching, and searching. It is also a project in the history of infrared astronomy looking for the first astronomical infrared source discovered in the constellation of Crux.

Nearly all the background you need to participate and learn by doing you've probably already been introduced to at a secondary level and perhaps even a primary education level.

Some of the material and information is at the college or university level, and as you progress in finding infrared sources, you'll run into concepts and experimental tests that are an actual search.

Selected quiz

## Blue astronomy quiz

This is a detailed, photo-like view of Earth based largely on observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite. Credit: Robert Simmon and Marit Jentoft-Nilsen, NASA.

Blue astronomy is a lecture from the astronomy department for the course on the principles of radiation astronomy.

You are free to take this quiz based on blue astronomy at any time.

To improve your scores, read and study the lecture, the links contained within, listed under See also, External links, and in the {{principles of radiation astronomy}} template. This should give you adequate background to get 100 %.

As a "learning by doing" resource, this quiz helps you to assess your knowledge and understanding of the information, and it is a quiz you may take over and over as a learning resource to improve your knowledge, understanding, test-taking skills, and your score.

Suggestion: Have the lecture available in a separate window.

To master the information and use only your memory while taking the quiz, try rewriting the information from more familiar points of view, or be creative with association.

Enjoy learning by doing!

Selected laboratory

## Cosmogony laboratory

This is an image of Chaos magnum from a book. Credit: Sailko.

This laboratory is an activity for you to create a universe. While it is part of the astronomy course principles of radiation astronomy, it is also independent.

Some suggested primordial entities to consider are electromagnetic radiation, neutrinos, mass, time, Euclidean space, Non-Euclidean space, dark matter, dark energy, purple phantoms, and spacetime.

More importantly, there are your primordial entities.

And, yes, you can create a universe from a peanut butter and jelly sandwich if you wish to.

You may choose to define your primordial entities or not.

Usually, research follows someone else's ideas of how to do something. But, in this laboratory you can create these too.

This is an astronomy cosmogony laboratory, but you may create what an astronomy, a cosmogony, or a laboratory is.

Yes, this laboratory is structured. And, you are providing it. Or, not, an unstructured universe is okay too.

I will provide an example of a cosmogony. The rest is up to you.

Questions, if any, are best placed on the discussion page. Please put your laboratory results, you'd like evaluated, on the laboratory's discussion page.

Selected problems

## Angular momentum and energy

This diagram describes the relationship between force (F), torque (τ), momentum (p), and angular momentum (L) vectors in a rotating system. 'r' is the radius. Credit: Yawe.

Angular momentum and energy are concepts developed to try to understand everyday reality.

An angular momentum L of a particle about an origin is given by

${\displaystyle \mathbf {L} =\mathbf {r} \times \mathbf {p} }$

where r is the radius vector of the particle relative to the origin, p is the linear momentum of the particle, and × denotes the cross product (r · p sin θ). Theta is the angle between r and p.

Please put any questions you may have, and your results, you'd like evaluated, on the problem set's discussion page.

Enjoy learning by doing!

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