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.

The Hubble Space Telescope image shows four high-velocity, runaway stars plowing through their local interstellar medium. Credit: NASA - Hubble's Advanced Camera for Surveys.

The image on the right shows four high-velocity, runaway stars plowing through their local interstellar medium.

"Resembling comets streaking across the sky, these four speedy stars are plowing through regions of dense interstellar gas and creating brilliant arrowhead structures and trailing tails of glowing gas."

"These bright arrowheads, or bow shocks, can be seen in these four images taken with NASA's Hubble Space Telescope. The bow shocks form when the stars' powerful stellar winds, streams of matter flowing from the stars, slam into surrounding dense gas. The phenomenon is similar to that seen when a speeding boat pushes through water on a lake." Read more...

Selected lecture

## Strong forces

"In field theory it is known that coupling constants “run”. This means that the values of the coupling constants that one measures depend on the energy at which the measurement is performed. [...] the three different coupling constants [one each for the strong force, electromagnetic force, and the weak force] of the standard model seem to converge to the same value at an energy scale of about 1016 GeV [...] This suggests that there is only one coupling constant at high energies and most likely only one symmetry group. [...] The current belief [is] that the electromagnetic, weak and strong forces [are] unified at about 1016 GeV [as such] one has to rely on [the] particle physics interactions which can lead to electromagnetic radiation and cosmic rays".[1]

### References

1. Tanmay Vachaspati (1998). "Topological defects in the cosmos and lab". Contemporary Physics 39 (4): 225-37. doi:10.1080/001075198181928. Retrieved 2013-11-05.
Selected theory

This animation depicts the collision between our Milky Way galaxy and the Andromeda galaxy. Credit: Visualization Credit: NASA; ESA; and F. Summers, STScI; Simulation Credit: NASA; ESA; G. Besla, Columbia University; and R. van der Marel, STScI.

Most of the mathematics needed to understand the information acquired through astronomical radiation observation comes from physics. But, there are special needs for situations that intertwine mathematics with phenomena that may not yet have sufficient physics to explain the observations. Both uses constitute radiation mathematics, or astronomical radiation mathematics, or a portion of mathematical radiation astronomy.

Astronomical radiation mathematics is the laboratory mathematics such as simulations that are generated to try to understand the observations of radiation astronomy.

The mathematics needed to understand radiation astronomy starts with arithmetic and often needs various topics in calculus and differential equations to produce likely models.

Selected topic

## Continua

The 15" refractor at Comanche Springs Astronomy Campus had its finder scope (a Stellarvue 80/9D achromat) equipped with a Baader Herschel Solar Wedge and a Solar Continuum Filter for today's transit of Venus. Credit: Jeff Barton from Richardson, TX, USA.`{{free media}}`

Lyc photon or Ly continuum photon or Lyman continuum photon are a kind of photon emitted from stars. Hydrogen is ionized by absorption of Lyc photons. Lyc photons are in the ultraviolet portion of the electromagnetic spectrum of the hydrogen atom and immediately next to the limit of the Lyman series of the spectrum with wavelengths that are shorter than 91.1267 nanometres and with energy above 13.6 eV.

Selected X-ray astronomy article
The MeV Auroral X-ray Imaging and Spectroscopy experiment (MAXIS) is carried aloft by a balloon.
Between January 12-30, 2000 the MAXIS balloon successfully circumnavigated the South Pole.

One of the recent balloon-borne experiments was called the High-resolution gamma-ray and hard X-ray spectrometer (HIREGS). It was first launched from McMurdo Station, Antarctica, in December 1991, when steady winds carried the balloon on a circumpolar flight lasting for about two weeks.

 ...Archive Read more on Wikiversity or High-altitude balloon on Wikipedia...
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 positron source in Phoenix

Positron astronomy results have been obtained using the INTEGRAL spectrometer SPI shown. Credit: Medialab, ESA.

The first positron source in Phoenix is unknown.

The field of positron astronomy is the result of observations and theories about positron sources detected in the sky above.

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

But, positrons from the Sun are intermingled with other radiation so that the Sun may appear as other than a primary source for positrons.

The early use of sounding rockets and balloons to carry positron detectors high enough may have detected positrons from the Sun as early as the 1940s.

This is a lesson in map reading, coordinate matching, and researching. It is also a research project in the history of positron astronomy looking for the first astronomical positron source discovered in the constellation of Phoenix.

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 positron sources, you'll run into concepts and experimental tests that are actual research.

Selected quiz

This is an animation of a radiation scintillation counter. Credit: KieranMaher.

Radiation astronomy detectors is a lecture as part of the radiation astronomy department course on the principles of radiation astronomy.

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

To improve your score, 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.

This quiz may need up to an hour to take and is equivalent to an hourly.

Enjoy learning by doing!

 ...Archive Try the quiz...
Selected laboratory

## Electron beam heating laboratory

This is an X-ray image of the coronal clouds near the Sun. Credit: NASA Goddard Space Flight Center.

This laboratory is an activity for you to create a method of heating the solar corona or that of a star of your choice. While it is part of the astronomy course principles of radiation astronomy, it is also independent.

Some suggested entities to consider are electromagnetic radiation, electrons, positrons, neutrinos, gravity, time, Euclidean space, Non-Euclidean space, magnetic reconnection, or spacetime.

More importantly, there are your entities.

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

Okay, this is an astronomy coronal heating laboratory.

Yes, this laboratory is structured.

I will provide an example of electron beam heating calculations. The rest is up to you.

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

Enjoy learning by doing!

 ...Archive Experiment...
Selected problems

## Furlongs per fortnight

It's about the chains. Credit: Stilfehler.`{{free media}}`

Furlongs per fortnight is a problem set with a contained quiz that focuses on the fundamentals of observational and deductive astronomy. In the activity Energy phantoms you learned about the value of distance, or displacement, and motion, speed, velocity, and acceleration. Here, you can practice and test yourself on converting from units that may or have occurred in the literature to units popular today.

Notation: let the symbol ${\displaystyle R_{\oplus }}$ indicate the Earth's radius.

Notation: let the symbol ${\displaystyle R_{J}}$ indicate the radius of Jupiter.

Notation: let the symbol ${\displaystyle R_{\odot }}$ indicate the solar radius.

Both physics and astronomy use units and dimensions to describe observations.

Units of Physics and Astronomy
Dimension Astronomy Symbol Physics Symbol Conversion
time 1 day d 1 second s 1 d = 86,400 s[1]
time 1 "Julian year"[2] J 1 second s 1 J = 31,557,600 s
distance 1 astronomical unit AU 1 meter m 1 AU = 149,597,870.691 km[1]
angular distance 1 parsec pc 1 meter m 1 pc ~ 30.857 x 1012 km[1]
 ...Archive Try the problems and the quiz...

### References

1. P. K. Seidelmann (1976). Measuring the Universe The IAU and astronomical units. International Astronomical Union. Retrieved 2011-11-27.
2. International Astronomical Union "SI units" accessed February 18, 2010. (See Table 5 and section 5.15.) Reprinted from George A. Wilkins & IAU Commission 5, "The IAU Style Manual (1989)" (PDF file) in IAU Transactions Vol. XXB
Selected X-ray astronomy pictures

The Crab Nebula is a remnant of an exploded star. This is the Crab Nebula in various energy bands, including a hard X-ray image from the HEFT data taken during its 2005 observation run. Each image is 6′ wide.

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