(Correction: A previous version of this article incorrectly stated the distance between Pluto and the Sun. The accurate figure is 3.7 billion miles.)
What was found in Flagstaff, Arizona, and eliminated in Prague?
If you said "Pluto's planethood," then your understanding of astronomy is spot-on.
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Feb. 18 marks the 95th anniversary of the discovery of our solar system's former ninth planet—not a planet.
Here’s what you should know regarding the brief existence of what was, within one person's lifespan, considered the tiniest planet in our solar system.
When was Pluto discovered?
Clyde Tombaugh, an American astronomer working at the Lowell Observatory in Flagstaff, found Pluto in 1930.
Chilly, dimly lit, and far away, it was renamed after the Roman deity of the Underworld In Greek mythology, the associated deity is Hades.
The planet's presence was initially hypothesized over three decades prior by American astronomer Percival Lowell. His analysis of planetary orbit patterns, meteor shower trajectories, and comet paths guided him to this conclusion. propose the presence of a ninth planet , which became known as Planet X.
Lowell looked for this distant planet, yet he passed away in 1916 without ever locating it.
Utilizing an instrument referred to as a blink comparator In 1930, Tombaugh ultimately discovered the enigmatic celestial object. The process entailed capturing sets of photographs of the night sky taken a few evenings apart and subsequently utilizing a specialized device to swiftly alternate between the two images. By doing this rapid alternation—or “blinking”—between pictures, the astronomer could detect subtle variations and identify motion.
Tombaugh endured long months at the unheated Lowell Observatory until February 1930 when he spotted a heavenly body moving between two images, as detailed in a study published by the institution. American Physical Society The discovery was reported on March 13, 1930.
Pluto's reign
For years, students memorized the saying "My Very Educated Mother Just Served Us Nine Pizzas" to recall the sequence of planets in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto.
Pluto was the final and smallest among them.
A small frozen planet, roughly half the size of the United States, typically resided about 3.7 billion miles away from the Sun. Its orbit was notably peculiar—highly elliptical and inclined at an angle. Sometimes it gets as close to the Sun as Neptune does. .
It features an atmosphere composed of methane, nitrogen, and carbon monoxide, with a surface temperature ranging from minus 378 to minus 396 degrees Fahrenheit, far too frigid to support life.
In 2015, NASA dispatched its spacecraft, New Horizons, for a close encounter. This mission verified that the small planet had an underground ocean concealed under its dense, icy crust.
When was Pluto reclassified as not being a planet, and what were the reasons for this change?
Pluto has consistently found itself in a precarious position regarding its status as a planet. With a width of just 1,477 miles, it measures merely one-fifth the size of our home planet, Earth.
It has five recognized satellites: Charon, Nix, Hydra, Kerberos, and Styx, which are all names derived from characters in Greek mythology linked to the underworld.
However, Charon was only half as large as Pluto, making it quite substantial in comparison. The Pluto-Charon system is often called a binary pair of planets. , according to NASA.
In August 2006, during the International Astronomical Union General Assembly, a resolution was passed to redesignate Pluto as a dwarf planet. This decision was based on the fact that it failed to meet one of the three new requirements established for classifying celestial bodies as planets. They were :
- The body needs to revolve around its host star, similar to how Earth and Jupiter circle the Sun.
- It is big enough to have a nearly spherical shape.
- This significant impact plays a crucial role in maintaining the orbital stability of nearby celestial bodies.
Due to failing to meet the final criteria, Pluto was downgraded to a dwarf planet following extensive discussions. This decision came from a majority vote conducted during the International Astronomical Union’s yearly gathering in Prague.
This led to significant public outrage. Caltech astronomer Michael Brown, whose research contributed to the demotion, received irate emails from students and some vulgar telephone calls .
He ultimately released a book called "Why I Executed Pluto and Why It Deserved It."
Tombaugh passed away in 1997. Never realizing the world he found had lost its planetary status .
The article initially appeared on USA TODAY. The small world once deemed a planet: Pluto's discovery celebrates its 95th anniversary today.
