Portal:Radiation astronomy
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.
Electromagnetic forces
"The emission of electromagnetic radiation from a superluminal (faster-than-light in vacuo) charged particle [is such] that no physical principle forbids emission by extended, massless superluminal sources. A polarization current density (dP/dt; see Maxwell's fourth equation) can provide such a source; the individual charged particles creating the polarization do not move faster than c, the speed of light, and yet it is relatively trivial to make the envelope of the polarization current density to do so."[1]
The "emitted radiation has many unusual characteristics, including: (i) the intensity of some components decays as the inverse of the distance from the source, rather than as 1/(distance)2 (i.e. these components are non-spherically-decaying); (ii) the emission is tightly beamed, the exact direction of the beam depending on the source speed; and (iii) the emission contains very high frequencies not present in the synthesis of the source. Note that the non-spherically decaying components of the radiation do not violate energy conservation. They result from the reception, during a short time period, of radiation emitted over a considerably longer period of (retarded) source time; their strong electromagnetic fields are compensated by weak fields elsewhere [1]."[1]
The "emission occupies a very small polar angular width of order 0.8 degrees in the far field. Based on these findings, we suggest that a superluminal source could act as a highly directional transmitter of MHz or THz signals over very long distances."[1]
"The magnetic field is well-ordered in many jets, as shown by polarization measurements. Synchrotron radiation can be very highly polarized (50%) if the field is globally ordered, and some sources [approach] this level. The electric vectors show clear structure and alignment; an especially common pattern is for the field lines to be along the jet in the inner portions and transition to an azimuthal configuration farther out. This is seen in [PKS0521-36 at 2 cm]."[2]
References
- ↑ 1.0 1.1 1.2 J. Singleton; A. Ardavan; H. Ardavan; J. Fopma; D. Halliday (2005). Non-spherically-decaying radiation from an oscillating superluminal polarization current: possible low-power, deep-space communication applications in the MHz and THz bands, 16th International Symposium on Space Terahertz Technology. pp. 117. http://www.nrao.edu/meetings/isstt/papers/2005/2005117000.pdf. Retrieved 2014-03-18.
- ↑ Bill Keel (October 2003). Jets, Superluminal Motion, and Gamma-Ray Bursts. Tucson, Arizona USA: University of Arizona. http://www.astr.ua.edu/keel/galaxies/jets.html. Retrieved 2014-03-19.
Mathematical radiation astronomy
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.
Bands
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.
With no strong central nuclear energy source, the interior of a brown dwarf is in a rapid boiling, or convective state. When combined with the rapid rotation that most brown dwarfs exhibit, convection sets up conditions for the development of a strong, tangled magnetic field near the surface. The flare observed by Chandra X-ray Observatory from LP 944-20 could have its origin in the turbulent magnetized hot material beneath the brown dwarf's surface. A sub-surface flare could conduct heat to the atmosphere, allowing electric currents to flow and produce an X-ray flare, like a stroke of lightning. The absence of X-rays from LP 944-20 during the non flaring period is also a significant result. It sets the lowest observational limit on steady X-ray power produced by a brown dwarf star, and shows that coronas cease to exist as the surface temperature of a brown dwarf cools below about 2500°C and becomes electrically neutral.
.jpg)
The Chandra X-ray Observatory X-ray image on the left of radio galaxy Pictor A shows a spectacular jet emanating from the center of the galaxy (left) that extends across 360 thousand lyr toward a brilliant hot spot. The bright spot at the right in the image is the head of the jet. Image is 4.2 arcmin across. RA 05h 19m 49.70s Dec -45° 46' 45" in Pictor. Instrument: ACIS. Credit: NASA/UMD/A.Wilson et al. The composite image on the right contains X-ray data obtained by Chandra at various times over 15 years (blue) and radio data from the Australia Telescope Compact Array (red). Credit: X-ray: NASA/CXC/Univ of Hertfordshire/M. Hardcastle et al., Radio: CSIRO/ATNF/ATCA.
First red source in Canis Major
The first red source in Canis Major is unknown.
This is a lesson in map reading, coordinate matching, and researching. It is also a research project in the history of red astronomy looking for the first astronomical red source discovered in the constellation of Canis Major.
Nearly all the background you need to participate and learn by doing you've probably already been introduced to at a secondary level.
Some of the material and information is at the college or university level, and as you progress in finding red sources, you'll run into concepts and experimental tests that are actual research.
To succeed in finding a red source in Canis Major is the first step.
Next, you'll need to determine the time stamp of its discovery and compare it with any that have already been found. Over the history of red astronomy a number of sources have been found, many as point sources in the night sky. These points are located on the celestial sphere using coordinate systems. Familiarity with these coordinate systems is not a prerequisite. Here the challenge is geometrical, astrophysical, and historical.
Radiation astrochemistry quiz
Radiation chemistry, or astronomical radiation chemistry, is a lecture for the course principles of radiation astronomy about the abundance and reactions of chemical elements and molecules in the universe.
You are free to take this quiz at any time and as many times as you wish to improve your score.
Once you’ve read and studied the lecture, the links contained within, and listed under See also, External links and those in the {{principles of radiation astronomy}} template, you should have adequate background to get 100 %.
Enjoy learning by doing!
Electron beam heating laboratory
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!
Angular momentum and energy
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
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!
Chandra image of two galaxies (Arp 270) in the early stage of a merger in the constellation Leo Minor. In the image, red represents low, green intermediate, and blue high-energy (temperature) X-rays. Image is 4 arcmin on a side. RA 10h 49m 52.5s Dec Template:Dec. Observation date: April 28, 2001. Instrument: ACIS. Credit: NASA/U. Birmingham/A.Read.
Fields associated with radiation astronomy include Astronomy, Astrogeology, Astrognosy, Astrohistory, Astrophysics, Atmospheric sciences, Charge ontology, Chemistry, Cosmogony, Fringe sciences, Geochemistry, Geochronology, Geology, Geomorphology, Geophysics, Geoseismology, Hydromorphology, Lofting technology, Mathematics, Measurements, Mining geology, Nuclear physics, Oceanography, Petrophysics, Radiation physics, Shielding, Spaceflights, Structural geology, Technology, Trigonometric-parallax astronomy, and X-ray trigonometric parallax
Other Wikiversity science-related portals: Anthropology - Archaeology - Astronomy - Biology - Biochemistry - Chemistry - Ecology - Fluid mechanics - Genetics - Hematology - Immunology - Life sciences - Materials science and engineering - Neurology - Organic chemistry - Particle physics - Quantum biology - Regional anatomy - Sciences - Technology
|
Wikiversity's sister projects
Wikiversity is hosted by the Wikimedia Foundation, a non-profit organization that also hosts a range of other multilingual and free-content projects:  Wikipedia
Free-content encyclopedia  Wikibooks
Free textbooks and manuals  Commons
Shared media repository  Incubator
Wikimedia incubator  Wiktionary
Dictionary and thesaurus  Wikiquote
Collection of quotations  Wikinews
Free-content news  Betawikiversity
Betawikiversity project  Wikispecies
Directory of species  Wikisource
Free-content library  Wikivoyage
Open travel guide  Phabricator
MediaWiki bug tracker  Meta-Wiki
Wikimedia project coordination  MediaWiki
Free software development  Wikidata
Free knowledge base  Wikimedia Labs
MediaWiki development Wikiversity is also available in other languages: |
Content by Subject
Arts ·
Humanities ·
Mathematics ·
Medicine ·
Science ·
Social Sciences ·
Technology
Content by Level
Pre-school Education ·
Primary Education ·
Secondary Education ·
Tertiary Education ·
Non-formal Education ·
Research