Feeds

Sky boffins: The Moon is not Earth's only natural satellite

'Minimoons' drop by, have a pint, overstay

Next gen security for virtualised datacentres

The Moon is not alone in its role as the Earth's natural satellite, although its companions are tiny fellows who usually don't stay long.

"At any given time there is at least one one-meter-diameter object orbiting the Earth," three astronomers write in the abstract of their article, "The population of natural Earth satellites", published in the March issue of the journal Icarus. "The average satellite makes about 3 revolutions around the Earth in 9 months."

According to the article's authors – Mikael Granvik of the University of Helsinki, Jeremie Vaubaillon of the Paris Observatory, and Robert Jedicke of the University of Hawaii at Manoa – the Earth's gravitational field regularly captures near-Earth objects (NEOs), which zip around terra firma for a bit, and are then flung back off into space to join their bretheren in heliocentric orbits.

The astronomers ran a computer simulation of 10 million asteroids passing the Earth, then tracked the trajectories of the 18,000 objects captured by Earth's gravity.

"This was one of the largest and longest computations I've ever done," said Vaubaillon in an announcement of the team's work. "If you were to try to do this on your home computer, it would take about six years." Luckily, Vaubaillon was able to run his simulation on the Jade supercomputer at the Centre Informatique National de l'Enseignement Supérieur (CINES) in Montpellier, France.

The trajectory of a 'minimoon' temporarily captured by the Earth's gravitational field

A tiny minimoon's path is nowhere near as stately as that of our 2,000-mile-diameter maxi-Moon (click to enlarge)

The simulation showed that NEOs are regularly trapped by the Earth's gravity, and that their orbital paths are highly distorted by the interaction of the gravitational forces exerted by the Earth, the Moon, and the Sun.

The irregular orbits of the NEOs – transformed into near-Earth satellites (NESs) or "minimoons" – sometime loop between the Earth and the Moon, and sometimes ourside them both. Interestingly, the team discovered that the Earth has a "small preference" for capturing minimoons in January and July.

The brief visitors – also known as temporarily-captured orbiters (TCOs) – can make as few as one orbit of the Earth or can hang around for decades, though the team says that an average visit lasts for about nine months. Some can even drop in for a visit, although the team calculates that only about 0.1 per cent of TCOs become meteorites.

Aside from possibly detecting an impending minimoon strike, the team notes that there are other benefits to knowing where such small visitors are orbiting. "Minimoons are scientifically extremely interesting," said Jedicke. "A minimoon could someday be brought back to Earth, giving us a low-cost way to examine a sample of material that has not changed much since the beginning of our solar system over 4.6 billion years ago." ®

Secure remote control for conventional and virtual desktops

More from The Register

next story
Our LOHAN spaceplane ballocket Kickstarter climbs through £8000
Through 25 per cent but more is needed: Get your UNIQUE rewards!
LOHAN tunes into ultra long range radio
And verily, Vultures shall speak status unto distant receivers
NASA to reformat Opportunity rover's memory from 125 million miles away
Interplanetary admins will back up data and get to work
SpaceX prototype rocket EXPLODES over Texas. 'Tricky' biz, says Elon Musk
No injuries or near injuries. Flight stayed in designated area
EOS, Lockheed to track space junk from Oz
WA facility gets laser-eyes out of the fog
Volcanic eruption in Iceland triggers CODE RED aviation warning
Lava-spitting Bárðarbunga prompts action from Met Office
LOHAN Kickstarter push breaks TWELVE THOUSAND POUNDS
That's right, folks, you've stumped up OVER 9,000 beer tokens - and counting
prev story

Whitepapers

Endpoint data privacy in the cloud is easier than you think
Innovations in encryption and storage resolve issues of data privacy and key requirements for companies to look for in a solution.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Advanced data protection for your virtualized environments
Find a natural fit for optimizing protection for the often resource-constrained data protection process found in virtual environments.
Boost IT visibility and business value
How building a great service catalog relieves pressure points and demonstrates the value of IT service management.
Next gen security for virtualised datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.