By Samantha Mathewson Published 18 hours ago
A 'giant' rising in the desert: World's largest telescope comes together (photo)
The Extremely Large Telescope is currently under construction, with the most recent milestones including progress made with building the dome, central structure and the base for the primary mirror.www.space.com
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Construction of the world's largest telescope moves forward with progress of the structure's dome and housing for the primary mirror.
NASA JPL discovers two types of comets that move like asteroids and discover dark comets.
Dec. 9, 2024
NASA Researchers Discover More Dark Comets
These celestial objects look like asteroids but act like comets now come in two flavors.www.jpl.nasa.gov
These celestial objects look like asteroids but act like comets now come in two flavors.
The first dark comet — a celestial object that looks like an asteroid but moves through space like a comet — was reported less than two years ago. Soon after, another six were found. In a new paper, researchers announce the discovery of seven more, doubling the number of known dark comets, and find that they fall into two distinct populations: larger ones that reside in the outer solar system and smaller ones in the inner solar system, with various other traits that set them apart.
The findings were published on Monday, Dec. 9, in the Proceedings of the National Academy of Sciences.
Scientists got their first inkling that dark comets exist when they noted in a March 2016 study that the trajectory of “asteroid” 2003 RM had moved ever so slightly from its expected orbit. That deviation couldn’t be explained by the typical accelerations of asteroids, like the small acceleration known as the Yarkovsky effect.
“When you see that kind of perturbation on a celestial object, it usually means it’s a comet, with volatile material outgassing from its surface giving it a little thrust,” said study coauthor Davide Farnocchia of NASA’s Jet Propulsion Laboratory in Southern California. “But try as we might, we couldn’t find any signs of a comet’s tail. It looked like any other asteroid — just a pinpoint of light. So, for a short while, we had this one weird celestial object that we couldn’t fully figure out.”
Weird Celestial Objects
Farnocchia and the astronomical community didn’t have to wait long for another piece of the puzzle. The next year, in 2017, a NASA-sponsored telescope discovered history’s first documented celestial object that originated outside our solar system. Not only did 1I/2017 U1 (‘Oumuamua) appear as a single point of light, like an asteroid, its trajectory changed as if it were outgassing volatile material from its surface, like a comet.
“‘Oumuamua was surprising in several ways,” said Farnocchia. “The fact that the first object we discovered from interstellar space exhibited similar behaviors to 2003 RM made 2003 RM even more intriguing.”
By 2023, researchers had identified seven solar system objects that looked like asteroids but acted like comets. That was enough for the astronomical community to bestow upon them their own celestial object category: “dark comets.” Now, with the finding of seven more of these objects, researchers could start on a new set of questions.
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Comet one day, asteroid the next and vice versa another one, for all eternity.
But they choose to call them 'dark comets', as if they were not the same in different electrical surrounding. You know, this habit of always putting things in different boxes without understanding the link between them.
From our dearest Pierre in Earth Changes and the Human-Cosmic Connection, p.78:
Amen.
