Parker Solar Probe Breaks Record, Becomes Closest Spacecraft to Sun
Parker Solar Probe now holds the record for closest approach to the Sun by a human-made object. The spacecraft passed the current record of 26.55 million miles from the Sun’s surface on Oct. 29, 2018, at about 1:04 p.m. EDT, as calculated by the Parker Solar Probe team.
The previous record for closest solar approach was set by the German-American Helios 2 spacecraft in April 1976. As the Parker Solar Probe mission progresses, the spacecraft will repeatedly break its own records, with a final close approach of 3.83 million miles from the Sun’s surface expected in 2024.
In early 2001 during a launch of Atlantis, the Sun, Earth, Moon, and rocket were all properly aligned for this photogenic coincidence.
Image Credit: Pat McCracken, NASA
In astronomy, an analemma is a diagram showing the variation of the position of the Sun in the sky over the course of a year, as viewed at a fixed time of day and from a fixed location on the Earth. The north–south component of the analemma is due to change of the Sun’s declination caused by the tilt of the Earth’s axis, and the east–west component is due to nonuniform rate of change of the Sun’s right ascension, governed by combined effects of axial tilt and Earth’s orbital eccentricity. The diagram has the form of a slender figure eight, and can often be found on globes of the Earth.
It is possible to photograph the analemma by keeping a camera at a fixed location and orientation and taking multiple exposures throughout the year, always at the same clock time (and accounting for daylight saving time, when and where applicable). Diagrams of analemmas frequently carry marks that show the position of the Sun at various closely spaced dates throughout the year. (The image of the analemma on Mars is only a simulation) (source)
Image credit: Tunç Tezel &
A Partial Solar Eclipse over Texas
Image Credit: Jimmy Westlake (Colorado Mountain College) & Linda Westlake
Solar flares produce gamma rays by several processes, one of which is
illustrated here. The energy released in a solar flare rapidly
accelerates charged particles. When a high-energy proton strikes matter
in the sun’s atmosphere and visible surface, the result may be a
short-lived particle – a pion – that emits gamma rays when it decays.
Credit: NASA’s Goddard Space Flight Center
The heliosphere is the bubble-like region of space dominated by the Sun, which extends far beyond the orbit of Pluto. Plasma “blown” out from the Sun, known as the solar wind, creates and maintains this bubble against the outside pressure of the interstellar medium, the hydrogen and helium gas that permeates the Milky Way Galaxy. The solar wind flows outward from the Sun until encountering the termination shock, where motion slows abruptly. The Voyager spacecraft have explored the outer reaches of the heliosphere, passing through the shock and entering the heliosheath, a transitional region which is in turn bounded by the outermost edge of the heliosphere, called the heliopause.
The shape of the heliosphere is controlled by the interstellar medium
through which it is traveling, as well as the Sun and is not perfectly
spherical. The limited data available and unexplored nature of these structures have resulted in many theories. The word “heliosphere” is said to have been coined by Alexander J. Dessler, who is credited with first use of the word in the scientific literature.
On September 12, 2013, NASA announced that Voyager 1 left the heliopause on August 25, 2012, when it measured a sudden increase in plasma density of about forty times. Because the heliopause marks one boundary
between the Sun’s solar wind and the rest of the galaxy, a spacecraft
such as Voyager 1 which has departed the heliosphere, can be said to
have reached interstellar space. source
AR9077: Solar Magnetic Arcade
On July 14th, solar active region 9077 (AR9077) produced a massive flare. The event also blasted an enormous cloud of energetic charged particles toward planet Earth, triggering magnetic storms and dramatic auroral displays. This striking close-up of AR9077 was made by the orbiting TRACE satellite shortly after the flare erupted. It shows million degree hot solar plasma cooling down while suspended in an arcade of magnetic loops.
Credit: TRACE, Stanford-Lockheed ISR, NASA
A prominence is a large, bright, gaseous feature extending outward from the Sun’s surface, often in a loop shape. Prominences are anchored to the Sun’s surface in the photosphere, and extend outwards into the Sun’s corona. While the corona consists of extremely hot ionized gases, known as plasma, which do not emit much visible light, prominences contain much cooler plasma, similar in composition to that of the chromosphere. The prominence plasma is typically a hundred times more luminous and denser than the coronal plasma. (source)
Neptune (red arc) completes one orbit around the Sun (center) for every 164.79 orbits of Earth. The light blue object represents Uranus.
The diffuse heliospheric current extends to the outer regions of the Solar System, and results from the influence of the Sun’s rotating magnetic field on the plasma in the interplanetary medium. source.