FROM WIKIPEDIA COMMONS
Neptune is the eighth planet from the Sun and the farthest known solar planet. In the Solar System, it is the fourth-largest planet by diameter, the third-most-massive planet, and the densest giant planet. It is 17 times the mass of Earth, and slightly more massive than its near-twin Uranus. Neptune is denser and physically smaller than Uranus because its greater mass causes more gravitational compression of its atmosphere. It is referred to as one of the solar system’s two ice giant planets (the other one being Uranus).
Being composed primarily of gases and liquids, it has no well-defined “solid surface”. The planet orbits the Sun once every 164.8 years at an average distance of 30.1 AU (4.5 billion km; 2.8 billion mi). It is named after the Roman god of the sea and has the astronomical symbol , representing Neptune’s trident.
Neptune is not visible to the unaided eye and is the only planet in the Solar System found by mathematical prediction rather than by empirical observation. Unexpected changes in the orbit of Uranus led Alexis Bouvard to hypothesise that its orbit was subject to gravitational perturbation by an unknown planet. After Bouvard’s death, the position of Neptune was predicted from his observations, independently, by John Couch Adams and Urbain Le Verrier. Neptune was subsequently observed with a telescope on 23 September 1846 by Johann Galle within a degree of the position predicted by Le Verrier. Its largest moon, Triton, was discovered shortly thereafter, though none of the planet’s remaining 13 known moons were located telescopically until the 20th century. The planet’s distance from Earth gives it a very small apparent size, making it challenging to study with Earth-based telescopes. Neptune was visited by Voyager 2, when it flew by the planet on 25 August 1989; Voyager 2 remains the only spacecraft to have visited Neptune. The advent of the Hubble Space Telescope and large ground-based telescopes with adaptive optics has recently allowed for additional detailed observations from afar.
Like Jupiter and Saturn, Neptune’s atmosphere is composed primarily of hydrogen and helium, along with traces of hydrocarbons and possibly nitrogen, though it contains a higher proportion of ices such as water, ammonia and methane. However, similar to Uranus, its interior is primarily composed of ices and rock; Uranus and Neptune are normally considered “ice giants” to emphasise this distinction. Along with Rayleigh scattering, traces of methane in the outermost regions in part account for the planet’s blue appearance. Newest data from the Gemini observatory shows the blue color is more saturated than the one present on Uranus due to thinner haze of Neptune’s more active atmosphere.
In contrast to the hazy, relatively featureless atmosphere of Uranus, Neptune’s atmosphere has active and visible weather patterns. For example, at the time of the Voyager 2 flyby in 1989, the planet’s southern hemisphere had a Great Dark Spot comparable to the Great Red Spot on Jupiter. More recently, in 2018, a newer main dark spot and smaller dark spot were identified and studied. In addition, these weather patterns are driven by the strongest sustained winds of any planet in the Solar System, with recorded wind speeds as high as 2,100 km/h (580 m/s; 1,300 mph). Because of its great distance from the Sun, Neptune’s outer atmosphere is one of the coldest places in the Solar System, with temperatures at its cloud tops approaching 55 K (−218 °C; −361 °F). Temperatures at the planet’s centre are approximately 5,400 K (5,100 °C; 9,300 °F). Neptune has a faint and fragmented ring system (labelled “arcs”), which was discovered in 1984, then later confirmed by Voyager 2.
Question of the Day
How can I get tree sap off my car?
Soak a rag in boiled linseed oil and leave it on the spot for several minutes. Then wash your car as usual.
Advice of the Day
Libras tend to be diplomatic, charming, easygoing, and sociable.
Home Hint of the Day
A musty suitcase can be refreshed by placing containers of cat litter inside and closing the suitcase for a few days. Repeat with fresh litter if necessary.
Word of the Day
This term harks back to the days when people believed in witches. An old Irish legend says that a witch could turn into a cat and regain herself eight times, but on the ninth time, August 17, she couldn’t change back, hence the saying: “A cat has nine lives.” Because August is a “yowly” time for cats, this may have prompted the speculation about witches on the prowl in the first place.
Puzzle of the Day
I move incessant to and fro, Obedient to Moon and Sun, But though I serve both high and low, All wait on me, I wait on none. (What am I?)
- Elizabeth Kortright Monroe (U.S. First Lady) – 1830
- Urbain Le Verrier (astronomer) – 1877
- William Marsh Rice (merchant) – 1900
- Sigmund Freud (psychologist) – 1939
- Chief Dan George (chief, actor) – 1981
- Bob Fosse (director, choreographer) – 1987
- Mary Frann (actress) – 1998
- Robert Wells (songwriter, co-wrote The Christmas Song) – 1998
- Victoria Woodhull (social reformer) – 1838
- William Stewart Halsted (surgeon) – 1852
- John Avery Lomax (folklorist) – 1867
- Walter Lippman (journalist) – 1889
- Elliot Roosevelt (politician) – 1910
- Mickey Rooney (actor) – 1920
- John Coltrane (musician) – 1926
- Ray Charles (musician) – 1930
- Mary Kay Place (actress) – 1947
- Bruce Springsteen (musician) – 1949
- Larry Mize (golf professional) – 1958
- Jason Alexander (actor) – 1959
- Chi McBride (actor) – 1961
- During the American Revolution, Captain John Paul Jones commanded a small squadron including the flagship USS Bonhomme Richard. On this date, in the evening, his squadron attacked the British frigate HMS Serapis and royal sloop Countess of Scarborough, which were guarding a convoy of merchant ships off the coast of England. The Bonhomme Richard engaged with the Serapis, commanded by Captain Richard Pearson, whereupon a 3.5-hour battle ensued. At one point, when asked to surrender, Jones is credited as saying: I have not yet begun to fight! Jones eventually achieved Pearson’s surrender and captured the Serapis and Countess of Scarborough. Both sides suffered heavy losses and the damaged Bonhomme Richard sank shortly after.– 1779
- N.Y. Knickerbocker Base Ball Club organized– 1845
- Planet Neptune was discovered– 1846
- Bryn Mawr College, the first U.S. graduate school for women, opened in Pennsylvania– 1885
- A time capsule was buried on the site of the NY World’s Fair, to be opened in the year 6939 to reveal such artifacts as a bible, mail order catalog, film of FDR, and college football game– 1938
- Big Thunder Mountain Railroad opened at Walt Disney World’s Magic Kingdom in Orlando, Florida– 1980
- Manon Rhéaume first woman player in an NHL game– 1992
- Cabot Creamery and Chef John Folse created the world’s largest macaroni and cheese. The previous record of 440 pounds was blown away by the team’s 2,469 pound macaroni and cheese.– 2010
- The remains of Hurricane Eloise merged with a stationary front over New York, Pennsylvania, and Maryland to produce major flooding– 1975
- Snow and sleet fell in Binghamton, New York– 1989
- The temperature in Richmond, Virginia, fell from 84 degrees F to 54 degrees F in 2 hours– 1989