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perilune

[ per-i-loon ]

noun

the point in a lunar orbit that is nearest to the moon.

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More about perilune

Perilune “the point in a lunar orbit that is nearest to the moon” is a compound of the combining form peri- “about, around, near” and the element -lune “moon.” Peri-, from Ancient Greek perí “about, around,” is a common fixture in words related to closeness, such as perimeter and periphery, and in perilune, it is combined with -lune on the pattern of perigee “the point in an orbit that is nearest to the earth” (using Ancient Greek gaîa or “earth”). Unlike perigee, perilune features a Latin-origin element, -lune (from Latin lūna) to mean “moon”; if this element were derived instead from Ancient Greek selḗnē “moon” to better match perigee, we would be saying something like “periselene” instead! Perilune was first recorded in English in the late 1950s.

how is perilune used?

After being tracked for several days the spacecraft would be further slowed so that its perilune, or closest approach, would be reduced to about 28 miles above the lunar surface, which would be the primary altitude for photography. Originally the plan was to make the initial orbit circular at about 575 miles above the lunar surface; the slowing maneuver would put the spacecraft into an elliptical orbit with a perilune of 28 miles and an apolune, or maximum altitude, of 575 miles.

Ellis Levin, Donald D. Viele, and Lowell B. Eldrenkamp, “The Lunar Orbiter Missions to the Moon,” Scientific American, Vol. 218, 1968

Since arriving at the Moon on 4 April, Beresheet has slowly lowered its orbit with a series of engine burns. On Tuesday, it circularized its orbit to an altitude of just 200 kilometers, and following a burn Wednesday, Beresheet dropped the perilune, or low point of its orbit, to just 15 kilometers over its eventual landing site in Mare Serenitatis.

Jason Davis, "Beresheet is about to Land on the Moon," Planetary Society, April 10, 2019

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Word of the day

autosomal

[ aw-tuh-soh-muhl ]

adjective

occurring on or transmitted by a chromosome other than one of the sex chromosomes.

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More about autosomal

Autosomal “occurring on a chromosome other than one of the sex chromosomes” is the adjectival form of autosome “a chromosome other than a sex chromosome,” a compound of the combining forms auto- “self, same” and -some “body.” Auto- comes from Ancient Greek autós “self,” of uncertain ultimate origin, while -some comes from Ancient Greek sôma “body,” the stem of which is sōmat-, as in somatic. While sôma refers to a body generally, nekrós (as in necropolis and necrotic) refers specifically to a dead body. Autosomal was first recorded in English in the early 20th century.

how is autosomal used?

Even if you are a descendant of Shakespeare, there is only a negligible chance [that you have] any of his DNA. This is because autosomal DNA gets passed on randomly …. Within 10 generations, Shakespeare’s DNA has spread out and recombined so many times that it doesn’t even really make sense to speak of a match. Putting the same point the other way, each of us has so many ancestors that … we don’t share any DNA with the vast majority of them.

Alva Noë, “Can You Tell Your Ethnic Identity From Your DNA?” NPR, February 12, 2016

What cannot be so quickly learned is how to compare two autosomal DNA profiles and understand what the overlapping fragments are hinting at, knowing which branch of a tree to focus on or seeing how these pieces will fit together to identify the unknown person. Mr. Holes said that genetic genealogists like Ms. Rae-Venter, “are worth their weight in gold,” because “they understand the DNA testing and DNA inheritance and the genealogy aspects,” which is rare to find in a single person.

Heather Murphy, "She Helped Crack the Golden State Killer Case. Here’s What She’s Going to Do Next." New York Times, August 29, 2018

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Word of the day

revitalize

[ ree-vahyt-l-ahyz ]

verb (used with object)

to give new vitality or vigor to.

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More about revitalize

Revitalize “to give new vitality or vigor to” is a compound of the prefix re- “again, back” and the verb vitalize “to give life to.” Vitalize, in turn, is formed from vital “of or relating to life” and the verbal suffix -ize. Vital, from Latin vītālis, comes from the Latin noun vīta “life,” which is derived from the same Proto-Indo-European root, gwei- “to live,” that is also the source of English quick (from Old English cwic “living”), Latin vīvere “to live” (as in vivacious and vivid), Ancient Greek bíos “life” (as in amphibian and biotic), and Ancient Greek zôion “animal” (as in protozoa and zodiac). Revitalize was first recorded in English in the late 1850s.

how is revitalize used?

In Canada, on the coastal fjords of British Columbia, within the Great Bear Rainforest, lies a swath of land the size of Ireland that protects thousand-year-old trees and the rarest bear in the world. Within it, Spirit Bear Lodge—owned and operated by the Kitasoo Xai’xais Nation—welcomes visitors from all over the world whose dollars revitalize local communities and fund further conservation, including a successful effort to stop bear hunts …. Douglas Neasloss, chief councilor of the Kitasoo Xai’xais Nation …. [says,] “We’ve been able to revitalize our culture and create a sustainable business model where we’re not pulling out a fish or cutting down a tree.”

Norie Quintos, “Should some of the world’s endangered places be off-limits to tourists?” National Geographic, October 12, 2021

The partnership between the tribe and university helped create the Myaamia Center located on the Miami campus. Center founder Daryl Baldwin of the Myaamia tribe and others revitalized a language that was declared dead in the 1960s. Since the center’s beginnings in 2001, the program has set the bar for Indigenous language and cultural revitalization, winning support from the National Science Foundation, the MacArthur Foundation, the Andrew Mellon Foundation and others.

Mary Annette Pember, "Myaamia tribe commemorates forced removal 175 years ago," Indian Country Today, October 18, 2021

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