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.
Source astronomy has its origins in the actions of intelligent life on Earth when they noticed things or entities falling from above and became aware of the sky. Sometimes what they noticed is an acorn or walnut being dropped on them or thrown at them by a squirrel in a tree. Other events coupled with keen intellect allowed these life forms to deduce that some entities falling from the sky are coming down from locations higher than the tops of local trees.
Def. a source or apparent source detected or “created at or near the time of the [ event or] events” is called a primary source.
Direct observation and tracking of the origination and trajectories of falling entities such as volcanic bombs presented early intelligent life with vital albeit sometimes dangerous opportunities to compose the science that led to source astronomy.
Cosmogony is any scientific theory concerning the coming into existence, or origin, of the cosmos or universe, or about how what sentient beings perceive as "reality" came to be.
Usually, the philosophy of cause and effect needs a beginning, a first cause. Modal logic may only require a probability rather than a sequence of events. The concept of uncountable suggests an unknown somewhere between a finite number of likely rationales and an infinite number of possibilities.
From a sense of time as moving forward from yesterday to today and onward to tomorrow, there is again a suggestion of a prehistoric time before the first hominins.
The use of any system of thought or emotion to perceive reality suggests that some existences may precede others.
When more detail becomes available an existence may be transformed into something, an entity, a source, an object, a rocky object, or out of existence.
As a topic in astronomy, cosmogony deals with the origin of each astronomical entity.
"[P]referential absorption of sunlight by ozone over long horizon paths gives the zenith sky its blueness when the sun is near the horizon".
"For quenched galaxies, the Hα absorption trough is deep and can be traced through the nucleus and along the major axis. It extends to a radius at or beyond 2 Rd [where Rd is the galaxy disk scale length] in all but three cases. This makes it possible to determine a velocity width from the optical spectrum as is done for emission line flux, with appropriate corrections between stellar and gas velocities (see discussion in Paper I, also Neistein, Maoz, Rix, & Tonry, 1999). In the few cases where a velocity width can also be measured from the H I data, it is found to be in good agreement with that taken from the Hα absorption line flux."
The Chamaeleon complex is a large star forming region (SFR) that includes the Chamaeleon I, Chamaeleon II, and Chamaeleon III dark clouds. It occupies nearly all of the constellation Chamaeleon and overlaps into Apus, Musca, and Carina.
In the image on the right, the contours are 100 µm emission from dust measured by the IRAS satellite.
On the left is a visual image of Arp 270. Credit: Aladin at SIMBAD. Chandra X-ray Observatory image on the right 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. Right ascension (RA) 10h 49m 52.5s Declination (Dec) +32° 59' 06"
. Observation date: April 28, 2001. Instrument: ACIS. Credit: NASA/U. Birmingham/A. Read.
The first ultraviolet source in Sagittarius is unknown.
The field of ultraviolet astronomy is the result of observations and theories about ultraviolet sources detected in the sky above.
The first astronomical ultraviolet source discovered may have been the Sun.
But, ultraviolet waves from the Sun are intermingled with other radiation so that the Sun may appear as other than a primary source for ultraviolet waves.
The early use of sounding rockets and balloons to carry ultraviolet detectors high enough may have detected ultraviolet waves 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 ultraviolet astronomy looking for the first astronomical ultraviolet source discovered in the constellation of Sagittarius.
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 ultraviolet sources, you'll run into concepts and experimental tests that are an actual search.
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.
This quiz may need up to an hour to take and is equivalent to an hourly.
Suggestion: Have the lecture available in a separate window.
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.
In astronomy we estimate distances and times when and where possible to obtain forces and energy.
The key values to determine in both force and energy are (L/T²) and (L²/T²). Force (F) x distance (L) = energy (E), L/T² x L = L²/T². Force and energy are related to distance and time using proportionality constants.
Every point mass attracts every single other point mass by a force pointing along the line intersecting both points. The force is proportional to the product of the two masses and inversely proportional to the square of the distance between them:
F is the force between the masses,
G is the gravitational constant,
m1 is the first mass,
m2 is the second mass, and
r is the distance between the centers of the masses.
In the International System of Units (SI) units, F is measured in newtons (N), m1 and m2 in kilograms (kg), r in meters (m), and the constant G is approximately equal to 6.674×10−11 N m2 kg−2.
Observationally, we may not know the origin of the force.
Coulomb's law states that the electrostatic force experienced by a charge, at position , in the vicinity of another charge, at position , in vacuum is equal to:
where is the electric constant and is the distance between the two charges.
Coulomb's constant is
where the constant is called the permittivity of free space in SI units of C2 m−2 N−1.
For reality, is the relative (dimensionless) permittivity of the substance in which the charges may exist.
↑- Proposition 75, Theorem 35: p.956 - I.Bernard Cohen and Anne Whitman, translators: Isaac Newton, The Principia: Mathematical Principles of Natural Philosophy. Preceded by A Guide to Newton's Principia, by I. Bernard Cohen. University of California Press 1999 ISBN0-520-08816-6ISBN0-520-08817-4
Chandra observations of the central regions of the Perseus galaxy cluster. Image is 284 arcsec across. RA 03h 19m 47.60sDec +41° 30' 37.00" in Perseus. Observation dates: 13 pointings between August 8, 2002 and October 20, 2004. Color code: Energy (Red 0.3-1.2 keV, Green 1.2-2 keV, Blue 2-7 keV). Instrument: ACIS. Credit: NASA/CXC/IoA/A.Fabian et al.