Asteroid Florence buzzes Earth, brings two moons along for the ride

4.5km rock is the largest object we've seen up close, albeit still 7,000,000km away


Be glad that the asteroid dubbed “Florence” won't revisit Earth for many, many years: observations during its weekend fly-by revealed that the space-rock is so big it's captured two moons.

Sky-watchers have been waiting for Florence (officially 3122 Florence) for some time: it was first spotted in 1981 by astronomer Schelte Bus using Australia's Siding Spring observatory and named after the nurse Florence Nightingale. The asteroid is big and bright enough that even though it missed us by several million kilometres over the weekend, backyard astronomers geared up to photograph it.

At around 4.5km in size, NASA explained last week, Florence is the largest object to pass this close since the agency began its work detecting and tracking near-Earth asteroids.

And it's also got a high albedo, with Sky & Telescope saying it reflects around 20 per cent of the sunlight that strikes it.

To track the flyby, NASA used the 70-metre antenna at its Goldstone Deep Space Communications Complex and found an unexpected pair of moons, both estimated to be between 100 and 300 metres across. That makes the asteroid just the third discovered to have a three-object system.

The inner moon's orbit is estimated at around eight hours, and between 22 and 27 hours for the outer moon.

NASA adds:

The radar images also provide our first close-up view of Florence itself. Although the asteroid is fairly round, it has a ridge along its equator, at least one large crater, two large flat regions, and numerous other small-scale topographic features. The images also confirm that Florence rotates once every 2.4 hours, a result that was determined previously from optical measurements of the asteroid’s brightness variations.

Further observations using Goldstone's Solar System Radar and the NSF Aricebo Observatory through September 8 will help estimate the asteroid's total mass and density, NASA says.

NASA reckons Florence won't come this close again until some time after 2500. ®

Similar topics


Other stories you might like

  • World’s smallest remote-controlled robots are smaller than a flea
    So small, you can't feel it crawl

    Video Robot boffins have revealed they've created a half-millimeter wide remote-controlled walking robot that resembles a crab, and hope it will one day perform tasks in tiny crevices.

    In a paper published in the journal Science Robotics , the boffins said they had in mind applications like minimally invasive surgery or manipulation of cells or tissue in biological research.

    With a round tick-like body and 10 protruding legs, the smaller-than-a-flea robot crab can bend, twist, crawl, walk, turn and even jump. The machines can move at an average speed of half their body length per second - a huge challenge at such a small scale, said the boffins.

    Continue reading
  • IBM-powered Mayflower robo-ship once again tries to cross Atlantic
    Whaddayaknow? It's made it more than halfway to America

    The autonomous Mayflower ship is making another attempt at a transatlantic journey from the UK to the US, after engineers hauled the vessel to port and fixed a technical glitch. 

    Built by ProMare, a non-profit organization focused on marine research, and IBM, the Mayflower set sail on April 28, beginning its over 3,000-mile voyage across the Atlantic Ocean. But after less than two weeks, the crewless ship broke down and was brought back to port in Horta in the Azores, 850 miles off the coast of Portugal, for engineers to inspect.

    With no humans onboard, the Mayflower Autonomous Ship (MAS) can only rely on its numerous cameras, sensors, equipment controllers, and various bits of hardware running machine-learning algorithms to survive. The computer-vision software helps it navigate through choppy waters and avoid objects that may be in its path.

    Continue reading
  • Revealed: The semi-secret list of techs Beijing really really wishes it didn't have to import
    I think we can all agree that China is not alone in wishing it had an alternative to Microsoft Windows

    China has identified "chokepoints" that leave it dependent on foreign countries for key technologies, and the US-based Center for Security and Emerging Technology (CSET) claims to have translated and published key document that name the technologies about which Beijing is most worried.

    CSET considered 35 articles published in Science and Technology Daily from April until July 2018. Each story detailed a different “chokepoint” or tech import dependency that China faces. The pieces are complete with insights from Chinese academics, industry insiders and other experts.

    CSET said the items, which offer a rare admission of economic and technological vulnerability , have hitherto “largely unnoticed in the non-Chinese speaking world.”

    Continue reading

Biting the hand that feeds IT © 1998–2022