Short answers, pulled from the story.
The solar wind is a stream of charged particles released from the Sun's corona, consisting mostly of electrons, protons, and alpha particles. It also contains trace amounts of heavier ions and atomic nuclei including carbon, nitrogen, oxygen, neon, magnesium, silicon, sulfur, and iron, as well as rarer traces of phosphorus, titanium, chromium, and certain isotopes of nickel.
Eugene Parker theoretically predicted the solar wind in a paper submitted to The Astrophysical Journal in 1958, giving the phenomenon its name. The first direct observational confirmation came in January 1959, when the Soviet spacecraft Luna 1 measured it using hemispherical ion traps.
The solar wind exists in two main states. The slow solar wind travels at roughly 300 kilometers per second, while the fast solar wind reaches a typical velocity of 750 kilometers per second. Near Earth at 1 astronomical unit, speeds range from 250 to 750 km/s.
Earth's magnetic field deflects most solar wind particles, but fluctuations in solar wind speed, density, and direction cause auroras, geomagnetic storms, and variations in ionizing radiation and radio interference that can range by factors of hundreds to thousands. During intense events, the magnetosphere's shape can shift by several Earth radii, exposing geosynchronous satellites to direct solar wind.
Parker Solar Probe is a NASA spacecraft launched in 2018 and named after astrophysicist Eugene Parker, who was 91 and present at the launch. Over a seven-year mission spanning twenty-four orbits, it studies the structure and dynamics of the solar corona to understand how particles are heated and accelerated as solar wind. On the 28th of April 2021, it became the first spacecraft to cross the Alfvén surface at 18.8 solar radii from the Sun.
Mars is thought to have lost up to a third of its original atmosphere to solar wind stripping, leaving an atmosphere about one-hundredth as dense as Earth's. NASA's MAVEN mission measured the current rate of atmospheric loss at roughly 100 grams per second. Venus, which lacks a significant magnetic field, has developed a comet-like tail sculpted by the solar wind that extends as far as Earth's orbit.