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Radiation astronomy
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 radiation astronomy

Ultraviolet astronomy is radiation astronomy applied to the ultraviolet phenomena of the sky, especially at night. It is also conducted above the Earth's atmosphere and at locations away from the Earth as a part of explorational (or exploratory) ultraviolet astronomy.

Acquiring a suntan may be a student's first encounter with an astronomical ultraviolet source. This probably occurs at the secondary level. How this source generates ultraviolet rays is usually introduced at the university or tertiary educational level.

The color of a star, as determined by the peak frequency of the visible light, depends on the temperature of the star's outer layers, including its photosphere. The effective temperature of the surface of the Sun's photosphere is 5,778 K. That's a peak emittance wavelength of 501.5 nm (~0.5 eV) making the photosphere a primarily green radiation source. The temperature of the photosphere is way too cool to generate appreciable amounts of ultraviolet. In fact, the Sun's photosphere probably generates little or no ultraviolet rays.

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Selected lecture

Radiation astronomy entities

This is an image of Johannes Vermeer's The astronomer. Credit: www.essentialvermeer.com : Home : Info : Pic.

Radiation astronomy entities, radiation entities, are any astronomical persons or things that have separate and distinct existences in empirical, objective or conceptual reality.

Some of them, like the astronomers of today, or at any time in the past, are relatively known. But there are many entities that are far less known or understood, such as the observers of ancient times who suggested that deities occupied the sky or the heavens. Likewise, these alleged deities may be entities, or perhaps something a whole lot less.

Astronomical X-ray entities are often discriminated further into sources or objects when more information becomes available, including that from other radiation astronomies.

A researcher who turns on an X-ray generator to study the X-ray emissions in a laboratory so as to understand an apparent astronomical X-ray source is an astronomical X-ray entity. So is one who writes an article about such efforts or a computer simulation to possibly represent such a source.

"The X-ray luminosity of the dominant group [an entity] is an order of magnitude fainter than that of the X-ray jet."[1]

References

  1. A. Finoguenov, M.G. Watson, M. Tanaka, C.Simpson, M. Cirasuolo, J.S. Dunlop, J.A. Peacock, D. Farrah, M. Akiyama, Y. Ueda, V. Smolčič, G. Stewart, S. Rawlings, C.vanBreukelen, O. Almaini, L.Clewley, D.G. Bonfield, M.J. Jarvis, J.M. Barr, S. Foucaud, R.J. McLure, K. Sekiguchi, E. Egami (April 2010). "X-ray groups and clusters of galaxies in the Subaru-XMM Deep Field". Monthly Notices of the Royal Astronomical Society 403 (4): 2063-76. doi:10.1111/j.1365-2966.2010.16256.x. http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2966.2010.16256.x/full. Retrieved 2011-12-09. 
Selected theory

Theoretical radiation astronomy

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. http://heinonlinebackup.com/hol-cgi-bin/get_pdf.cgi?handle=hein.journals/ansurintcl1&section=4. 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)
Selected topic

Bands

This is Saturn imaged with the Stockholm Infrared Camera (SIRCA) in the H2O band. Credit: M. Gålfalk, G. Olofsson and H.-G. Florén, Nordic Optical Telescope.

At the right is Saturn imaged by the Stockholm Infrared Camera (SIRCA) in the H2O infrared band to show the presence of water vapor. The image is cut off near the top due to the presence of Saturn's rings.

The Sun's emission in the lowest UV bands, the UVA, UVB, and UVC bands, are of interest, as these are the UV bands commonly encountered from artificial sources on Earth. The shorter bands of UVC, as well as even more energetic radiation as produced by the Sun, generate the ozone in the ozone layer when single oxygen atoms produced by UV photolysis of dioxygen react with more dioxygen. The ozone layer is especially important in blocking UVB and part of UVC, since the shortest wavelengths of UVC (and those even shorter) are blocked by ordinary air.

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.

Objects
Selected image
Chandra image of Cygnus X-1.jpg

Chandra X-ray Observatory imaged Cygnus X-1. Credit: Chandra: NASA/CXC.

Selected lesson

First superluminal source in Indus

This is an Aladin at SIMBAD image of ICRF J230343.5-680737, a Seyfert 1 galaxy in the constellation Indus. Credit: Aladin at SIMBAD.

The first superluminal source in Indus is unknown.

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

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

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

The early use of sounding rockets and balloons to carry superluminal detectors high enough may have detected superluminal 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 superluminal astronomy looking for the first astronomical superluminal source discovered in the constellation of Indus.

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 superluminal 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 radiation 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

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.

Please define your entities or use available definitions.

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!

Selected problems

Column densities

A region of the sky called the "Lockman Hole", located in the constellation of Ursa Major, is one of the areas surveyed in infrared light by the Herschel Space Observatory. Credit: ESA/Herschel/SPIRE/HerMES.

A column density is the number of units of matter observed along a line of sight that has an area of observation. This area has a height that is the distance to an object, or through which observation is taking place.

"A region of the sky [at right] called the "Lockman Hole", located in the constellation of Ursa Major, is one of the areas surveyed in infrared light by the Herschel Space Observatory. All of the little dots in this picture are distant galaxies. The pattern of their collective light is what's known as the cosmic infrared background. By studying this pattern, astronomers were able to measure how much dark matter it takes to create a galaxy bursting with young stars."[1]

References

  1. Jamie Bock (February 16, 2011). Herschel's View of 'Lockman Hole'. Pasadena, California USA: Caltech. Retrieved 2014-03-15.
Selected X-ray astronomy pictures
November 3 2009 GOES14 Image.png

The GOES 14 spacecraft carries a Solar X-ray Imager to monitor the Sun’s X-rays for the early detection of solar flares, coronal mass ejections (CMEs), and other phenomena that impact the geospace environment.

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