Solar wind

The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona. This plasma consists of electrons and alpha particles with kinetic energy between 0.5 and 10 keV. The composition of the solar wind plasma includes a mixture of materials found in the solar plasma: trace amounts of heavy ions and atomic nuclei C, N, O, Ne, Mg, Si, S, Fe. There are rarer traces of some other nuclei and isotopes such as P, Ti, Cr,Ni, Fe 54 and 56, Ni 58,60,62. Embedded within the solar-wind plasma is the interplanetary magnetic field; the solar wind varies in density and speed over time and over solar latitude and longitude. Its particles can escape the Sun's gravity because of their high energy resulting from the high temperature of the corona, which in turn is a result of the coronal magnetic field. At a distance of more than a few solar radii from the Sun, the solar wind reaches speeds of 250 to 750 kilometers per second and is supersonic, meaning it moves faster than the speed of the fast magnetosonic wave.

The flow of the solar wind is no longer supersonic at the termination shock. The Voyager 2 spacecraft crossed the shock more than five times between 30 August and 10 December 2007. Voyager 2 crossed the shock about a billion kilometers closer to the Sun than the 13.5-billion-kilometer distance where Voyager 1 came upon the termination shock. The spacecraft moved outward through the termination shock into the heliosheath and onward toward the interstellar medium. Other related phenomena include the aurora, the plasma tails of comets that always point away from the Sun, geomagnetic storms that can change the direction of magnetic field lines; the existence of particles flowing outward from the Sun to the Earth was first suggested by British astronomer Richard C. Carrington. In 1859, Carrington and Richard Hodgson independently made the first observation of what would be called a solar flare; this is a sudden, localised increase in brightness on the solar disc, now known to occur in conjunction with an episodic ejection of material and magnetic flux from the Sun's atmosphere, known as a coronal mass ejection.

On the following day, a geomagnetic storm was observed, Carrington suspected that there might be a connection, now attributed to the arrival of the coronal mass ejection in near-Earth space and its subsequent interaction with the Earth's magnetosphere. George FitzGerald suggested that matter was being accelerated away from the Sun and was reaching the Earth after several days. In 1910 British astrophysicist Arthur Eddington suggested the existence of the solar wind, without naming it, in a footnote to an article on Comet Morehouse; the idea never caught on though Eddington had made a similar suggestion at a Royal Institution address the previous year. In the latter case, he postulated that the ejected material consisted of electrons while in his study of Comet Morehouse he supposed them to be ions; the first person to suggest that the ejected material consisted of both ions and electrons was Kristian Birkeland. His geomagnetic surveys showed; as these displays and other geomagnetic activity were being produced by particles from the Sun, he concluded that the Earth was being continually bombarded by "rays of electric corpuscles emitted by the Sun".

In 1916, Birkeland proposed that, "From a physical point of view it is most probable that solar rays are neither negative nor positive rays, but of both kinds". In other words, the solar wind consists of positive ions. Three years in 1919, Frederick Lindemann suggested that particles of both polarities, protons as well as electrons, come from the Sun. Around the 1930s, scientists had determined that the temperature of the solar corona must be a million degrees Celsius because of the way it stood out into space. Spectroscopic work confirmed this extraordinary temperature. In the mid-1950s Sydney Chapman calculated the properties of a gas at such a temperature and determined it was such a superb conductor of heat that it must extend way out into space, beyond the orbit of Earth. In the 1950s, Ludwig Biermann became interested in the fact that no matter whether a comet is headed towards or away from the Sun, its tail always points away from the Sun. Biermann postulated that this happens because the Sun emits a steady stream of particles that pushes the comet's tail away.

Wilfried Schröder claimed that Paul Ahnert was the first to relate solar wind to comet tail direction based on observations of the comet Whipple-Fedke. Eugene Parker realised heat flowing from the Sun in Chapman's model and the comet tail blowing away from the Sun in Biermann's hypothesis had to be the result of the same phenomenon, which he termed the "solar wind". In 1957, Parker showed though the Sun's corona is attracted by solar gravity, it is such a good heat conductor that it is still hot at large distances. Since gravity weakens as distance from the Sun increases, the outer coronal atmosphere escapes supersonically into interstellar space. Furthermore, Parker was the first person to notice that the weakening effect of the gravity has the same effect on hydrodynamic flow as a de Laval nozzle: it incites a transition from subsonic to supersonic flow. Opposition to Parker's hypothesis on the solar wind was strong; the paper he submitted to The Astrophysical Journal in 1958 was rejected by two reviewers.

It was saved by the editor Subrahmanyan Chandrasekhar. In January 1959, the Soviet spacecraft Luna 1 first directly observed the solar wind and measured its strength, using hemispherical ion traps; the discovery, made b

181 Eucharis

Eucharis is a large rotating main-belt asteroid, discovered by French astronomer Pablo Cottenot on February 2, 1878, from Marseille Observatory. It was his only asteroid discovery; this object was named after a Greek nymph. In the Tholen classification system, it is categorized as a stony S-type asteroid, while the Bus asteroid taxonomy system lists it as an Xk asteroid. Photometric observations of this asteroid at the Goat Mountain Astronomical Research Station in Rancho Cucamonga, California during 2007 gave a light curve with a leisurely rotation period of 52.23 ± 0.05 hours. This object is the namesake of a family of 149–778 asteroids that share similar spectral properties and orbital elements. All members have a high orbital inclination. 181 Eucharis at AstDyS-2, Asteroids—Dynamic Site Ephemeris · Observation prediction · Orbital info · Proper elements · Observational info 181 Eucharis at the JPL Small-Body Database Close approach · Discovery · Ephemeris · Orbit diagram · Orbital elements · Physical parameters


Microsoft QuickBASIC is an Integrated Development Environment and compiler for the BASIC programming language, developed by Microsoft. QuickBASIC runs on DOS, though there was a short-lived version for the classic Mac OS, it is loosely based on GW-BASIC but adds user-defined types, improved programming structures, better graphics and disk support and a compiler in addition to the interpreter. Microsoft marketed QuickBASIC as the introductory level for their BASIC Professional Development System. Microsoft marketed two other similar IDEs for viz QuickC and QuickPascal. Microsoft released the first version of QuickBASIC on August 18, 1985 on a single 5.25" 360kB floppy disk. QuickBASIC version 2.0 and contained an Integrated Development Environment, allowing users to edit directly in its on-screen text editor. Although still supported in QuickBASIC, line numbers became optional. Program jumps worked with named labels. Versions added control structures, such as multiline conditional statements and loop blocks.

Microsoft's "PC BASIC Compiler". Beginning with version 4.0, the editor included an interpreter that allowed the programmer to run the program without leaving the editor. The interpreter was used to debug a program before creating an executable file. There were some subtle differences between the interpreter and the compiler, which meant that large programs that ran in the interpreter might fail after compilation, or not compile at all because of differences in the memory management routines; the last version of QuickBASIC was version 4.5, although development of the Microsoft BASIC Professional Development System continued until its last release of version 7.1 in October 1990. At the same time, the QuickBASIC packaging was silently changed so that the disks used the same compression used for BASIC PDS 7.1. The Basic PDS 7.x version of the IDE was called QuickBASIC Extended, it only ran on DOS, unlike the rest of Basic PDS 7.x, which ran on OS/2. The successor to QuickBASIC and Basic PDS was Visual Basic version 1.0 for MS-DOS, shipped in Standard and Professional versions.

Versions of Visual Basic did not include DOS versions, as Microsoft concentrated on Windows applications. A subset of QuickBASIC 4.5, named QBasic, was included with MS-DOS 5 and versions, replacing the GW-BASIC included with previous versions of MS-DOS. Compared to QuickBASIC, QBasic is limited to an interpreter only, lacks a few functions, can only handle programs of a limited size, lacks support for separate program modules. Since it lacks a compiler, it cannot be used to produce executable files, although its program source code can still be compiled by a QuickBASIC 4.5, PDS 7.x or VBDOS 1.0 compiler, if available. QuickBASIC 1.00 for the Apple Macintosh operating system was launched in 1988. It was supported on machines running System 6 with at least 1 MB of RAM. QuickBASIC could be run on System 7, as long as 32-bit addressing was disabled. Hello, shortest version: Hello, extended version: 99 bottles of beer: Graphics example: Bubble sort: QuickBASIC continues to be used in some schools as part of an introduction to programming, though it is fast becoming replaced by more popular compilers.

It has an unofficial community of hobby programmers who use the compiler to write video games, GUIs and utilities. The community has dedicated message boards and online magazines to the language. Today, programmers sometimes use DOS emulators, such as DOSBox, to run QuickBASIC on Linux and on modern personal computer hardware that no longer supports the compiler. Alternatives to this include FreeBASIC and QB64, but they cannot yet run all QBasic/QuickBASIC programs. Since 2008, a set of TCP/IP routines for QuickBASIC 4.x and 7.1 has revitalized some interest in the software. In particular, the vintage computer hobbyist community has been able to write software for old computers that run DOS, allowing these machines to access other computers through a LAN or the internet; this has allowed systems as old as an 8088 to serve new functions, such as acting as a Web server or using IRC. Microsoft's Visual Basic was the successor of QuickBASIC. Other compilers, like PowerBASIC and FreeBASIC, have varying degrees of compatibility.

QB64, a multiplatform QuickBASIC to C++ translator, retains close to 100% compatibility and compiles natively for Windows and macOS. QBasic Turbo Basic QB64 Version History of Microsoft QuickBasic for MS-DOS