Earth Probably Has Two Moons
As residents of Earth, we’ve grown accustomed to having just one moon. Let Saturn and its 62 moons be the solar system’s showboat; that just leaves us on this planet to enjoy our single natural satellite all the more.
Or so we thought. According to a new study by an international team of scientists, the Earth actually has two moons at any given time. One is the big bright orb we all know.
The other is an asteroid, about the size of a refrigerator, that gets caught in Earth’s gravitational pull as it’s whizzing through space. One such Near Earth Object (NEO), asteroid 2006 RH120, served as Earth’s second moon for a full year, from July 2006 through July 2007, before spinning off into the void.
“We predict that there is a one-meter-diameter or larger NEO temporarily orbiting the Earth at any given time,” according to the research paper, published recently in Icarus, a journal of solar system studies.
Right now is a very good time for Earth to find a new mate. The likelihood of capturing a new, tiny moon is highest in January, the scientists found, when the Earth is 146 million kilometers from the sun, the closest point in its orbit. Another good time is in July, the Earth’s farthest point in its solar orbit, when we are 150 million kilometers from the sun.
Once captured by the Earth’s gravitational pull, these “temporary moons” usually enjoy three highly elliptical passes around the planet, which takes them about nine months. But some moons probably stick around for years in more stable orbits, the researchers predict. If scientists could find such a stable temporary moon, the scientists hypothesize, a space agency might be able to send a rocket to meet the asteroid, and lasso it back down to Earth.
“The scientific potential of being able to first remotely characterize a meteoroid and then visit and bring it back to Earth would be unprecedented,” wrote the research team, which includes Mikael Granvik of the University of Hawaii and Jeremie Vaubaillon from the University of Helsinki.
To land on an asteroid and safely bring it down to Earth, first NASA would have to find one, and that can be tricky. Most temporary moons are too tiny and moving too fast to be detected, according to the study. They’re also too far away, usually staying two or three times farther away from the planet than our larger, more famous moon.
The one confirmed temporary moon, RH120, may have been detected by the Catalina Sky Survey in Arizona because it was larger than most, at approximately 10 to 20 feet wide. Source: Weird News
- Earth Has a Second Moon, Astronomers Say [Astronomy] (gizmodo.com)
- In 2006 Mystery Object RH120 was Earth’s 1st Documented Temporary Moon (2012indyinfo.com)
Rare Moon Mineral Found in Australia
A mineral brought back to Earth by the first men on the moon and long thought to be unique to the lunar surface has been found in Australian rocks more than one billion years old, scientists said Thursday.
Named after Apollo 11’s 1969 landing site at the Sea of Tranquility, tranquillityite was one of three minerals first discovered in rocks from the Moon and the only one not to be found, in subsequent years, on Earth.
Australian scientist Birger Rasmussen said tranquillityite had “long been considered as the moon’s own mineral” until geologists discovered it, by chance, in rock from resources-rich Western Australia.
“In over 40 years it hadn’t been found in any terrestrial samples,” Rasmussen, from Curtin University, said.
When the moon samples first came back Rasmussen said they were considered to be “extremely precious” and had been subjected to intense, detailed study when — ironically — their contents were “right here all the time.”
“They were always part of Earth, they haven’t come from the moon,” he said of his work on the discovery, published in the journal Geology.
“It tells you that broadly overall you have similar chemistries and similar processes operating on the moon as on Earth.”
As well as being “quirky and surprising” Rasmussen said the discovery also had important practical applications, with the mineral proving to be an excellent dating tool which had allowed scientists to pin down the rocks’ age.
“We used this mineral … to date the dolerite which has previously been undated, so that helped us understand the geological history,” he said.
They were 1.07 billion years old, more ancient than rocks in the area had previously been thought to be, and Rasmussen said tranquillityite would be useful in dating similar rocks in the future.
“I think it will be a lot more widespread than just the six locations we’ve found it so far,” he added of the rare mineral.Source: Discovery News