The Beacon: Hard Science Fiction by Brandon Morris (red white and royal blue hardcover TXT) 📕

by astronomical objects containing extremely hot gases with temperatures ranging from about one million degrees Kelvin (K) to hundreds of millions of degrees Kelvin. Although science predicted that the sun and the stars had to be important X-ray sources, there was no way to verify this for a long time.

The existence of solar X-rays was only confirmed in the middle of the 20th century by V-2 rockets, which had been converted to sounding rockets. The discovery of extraterrestrial X-rays was the primary or secondary task of several satellites launched since 1958. The first cosmic X-ray source outside the solar system was discovered by a sounding rocket in 1962. The source was named Scorpius X-1 (Sco X-1). The X-ray emission from Scorpius X-1 is 10,000 times greater than in the visual range, while that from the sun is about a million times less. In addition, the object’s energy emission in the X-ray region is 100,000 times greater than the sun’s total emission in all wavelengths. It is now known that Sco X-1 is a neutron star that sucks matter from its companion.

In the meantime, astronomers have discovered many thousands of X-ray sources. Moreover, we now know that the space between galaxies in galaxy clusters is filled with a very hot but highly diluted gas with a temperature of between 100 and 1,000 megakelvin. The total amount of hot gas in visible galaxies is five to ten times their total mass.

Today, specialized telescopes aboard satellites are used to observe X-ray sources. These currently include the XMM-Newton observatory (low to medium energy X-rays 0.1-15 keV) and the INTEGRAL satellite (high energy X-rays 15-60 keV). The European Space Agency launched both of these, and NASA has the Swift and Chandra observatories in orbit.

The GOES 14 spacecraft carries a Solar X-ray Imager that monitors the sun’s X-rays for early detection of solar flares, coronal mass ejections, and other phenomena that affect the space environment. It was launched into orbit at 22:51 GMT on June 27, 2009, from Space Launch Complex 37B at Cape Canaveral Air Force Station.

On January 30, 2009, the Russian Federal Space Agency successfully launched the Koronas-Foton (CORONAS-Photon) which has several X-ray detection experiments on board, including the TESIS telescope/spectrometer FIAN with the SphinX soft X-ray spectrophotometer.

ISRO (India) launched the Astrosat multi-wavelength space observatory into orbit in 2015. One of the unique features of the Astrosat mission is that it enables simultaneous multi-wavelength observations of various astronomical objects with a single satellite. Astrosat observes the universe in the optical and ultraviolet regions, and the low- and high-energy X-ray regions, of the electromagnetic spectrum, while most other scientific satellites can only observe a narrow range of the wavelength band.

The Astro-rivelatore Gamma a Immagini LEggero (AGILE) gamma-ray observatory satellite of the Italian Space Agency (ASI), has the Super-AGILE detector for hard X-rays from 15-45 keV on board. It was launched on April 23, 2007, with the Indian PSLV-C8.

The Hard X-ray Modulation Telescope (HXMT) is a Chinese X-ray space observatory launched on June 15, 2017, to observe black holes, neutron stars, active galactic nuclei, and other phenomena by their X-ray and gamma-ray emissions.

China’s CNSA launched the ‘Lobster-Eye X-ray Satellite’ on July 25, 2020. It is the first in-orbit telescope to use an ultra-large field of view to search for dark matter signals in the X-ray energy range.

Where did X-ray radiation come from, and what types of objects can we observe in this part of the spectrum? Quite different types of astrophysical objects emit, fluoresce, or reflect X-rays, from galaxy clusters to black holes in active galactic nuclei (AGN) to galactic objects such as supernova remnants, stars, and binaries containing a white dwarf (cataclysmic variable stars and super-soft X-ray sources), a neutron star, or a black hole (X-ray binaries).

But some objects in the solar system also emit X-rays. The most notable is the moon, with most of its X-ray brightness coming from reflected solar X-rays.

A combination of many unresolved X-ray sources is thought to produce the X-ray background observed across the entire firmament. The X-ray continuum can arise from bremsstrahlung (braking radiation), blackbody radiation, synchrotron radiation, or the so-called inverse Compton scattering of low-energy photons by relativistic electrons, as well as collisions of fast protons with atomic electrons, and atomic recombination with or without additional electron transitions.

Radio Astronomy

Radio astronomy is a branch of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object occurred in 1932 when Karl Jansky observed radiation from the Milky Way at the Bell Telephone Laboratories. Subsequent observations have identified a number of different sources of radio emission. These include stars and galaxies, but also entirely new classes of objects such as radio galaxies, quasars, and pulsars. Radio astronomy has also been used to discover cosmic microwave background radiation, which is considered evidence for the Big Bang theory.

Radio astronomy is performed with large radio antennas, called radio telescopes, which are used either singly or connected in multiples. By using interferometry, radio astronomy can achieve high angular resolution because the resolving power of an interferometer is determined by the distance between its components, not by the size of its components.

Radio astronomers use various techniques to observe objects in the radio spectrum. They simply point their instruments at a high-energy radio source to analyze its emission. To create an image of a region of the sky in more detail, they take multiple overlapping scans and assemble them into a mosaic image. The type of instrument used depends on the strength of the signal and the level of detail required.

However, observations from the Earth’s surface are limited to wavelengths that can penetrate the atmosphere. At low frequencies or long wavelengths, the Earth’s ionosphere limits transmission because it reflects waves below a certain frequency. On the other hand, water vapor interferes with radio astronomy at higher frequencies. Therefore, people like to build radio observatories at very high, dry locations so that the water vapor content in the line of sight remains minimal. Finally, transmitting equipment on Earth can cause