Large Asteroid to Safely Pass Earth on Sept. 1

Aug 29, 2017

Asteroid Florence, a large near-Earth asteroid, will pass safely by Earth on Sept. 1, 2017, at a distance of about 4.4 million miles, (7.0 million kilometers, or about 18 Earth-Moon distances). Florence is among the largest near-Earth asteroids that are several miles in size; measurements from NASA’s Spitzer Space Telescope and NEOWISE mission indicate it’s about 2.7 miles (4.4 kilometers) in size.

“While many known asteroids have passed by closer to Earth than Florence will on September 1, all of those were estimated to be smaller,” said Paul Chodas, manager of NASA’s Center for Near-Earth Object Studies (CNEOS) at the agency’s Jet Propulsion Laboratory in Pasadena, California. “Florence is the largest asteroid to pass by our planet this close since the NASA program to detect and track near-Earth asteroids began.”

This relatively close encounter provides an opportunity for scientists to study this asteroid up close. Florence is expected to be an excellent target for ground-based radar observations. Radar imaging is planned at NASA’s Goldstone Solar System Radar in California and at the National Science Foundation’s Arecibo Observatory in Puerto Rico. The resulting radar images will show the real size of Florence and also could reveal surface details as small as about 30 feet (10 meters).

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3 comments on “Large Asteroid to Safely Pass Earth on Sept. 1

  • Another one missed us – this time!

    Around midday UK time on 1 September, 3122 Florence passed little more than 7 million kilometres (4.39 million miles), or 18 lunar distances, from Earth. Given its size and current proximity, the asteroid will be brighter than the tenth magnitude for the next few days as it tracks across the Milky Way, hence it’s easy object for small telescopes despite the light of a waxing gibbous Moon.

    On the UK night of 2—3 September (Saturday night, Sunday morning) 3122 Florence lies 0.049 astronomical units (7.33 million kilometres) from our planet, travelling at a rate of 9 degrees/day (22½ arcseconds/minute) against the stars of Delphinus, a small constellation better known as the dolphin. The following wide-angle star chart shows you how to locate Delphinus.

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  • We really should be watching these objects more closely.
    The dinosaurs didn’t! 🙂
    Over 2015-2016, observers discovered more than 1500 previously unknown NEOs each year. Roughly half of the known catalogue of NEOs are objects larger than about 460 feet (140 meters) in size. The estimated population of NEOs of this size is about 25,000. Current surveys are finding NEOs of this size at a rate of about 500 per year.

    The 460-foot cutoff point was established by a NASA NEO survey science definition team (SDT) in 2003. The SDT determined that impacts from objects of that size would only produce regional effects, while larger objects would have corresponding wider effects such as large sub-global effects from impacts of a 984-foot (300-meter) object and global effects from 0.6 mile (1-kilometer) object impacts. In 2016, NASA appointed a new NEO survey SDT to reevaluate this cutoff point in light of research conducted and events occurring since 2003. The new SDT’s recommendations should be available in 2017.

    Ground-based telescopes alone have limitations – for instance, they can only survey the skies at night and in clear skies. Based on statistical population estimates, about 74 percent of NEOs larger than 460 feet still remain to be discovered.

    What can be done to improve the NEO detection rate?

    Larger ground-based telescopes and a dedicated space-based infrared asteroid survey telescope would substantially increase the discovery rate and meet the goal in the NASA Authorization Act of 2005 to detect, track, catalogue, and characterize the physical characteristics of 90 percent of the NEO population down to 140 meters in size. NASA’s currently operating NEOWISE space-based survey was not designed for this purpose. NEOWISE is a repurposed astrophysics spacecraft, and while it has made significant contributions to NEO discovery and characterization, its capabilities are limited.

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  • While the NRA is playing political macho-clowns waving big guns, and Trump is posturing about military parades, the USA should be supporting its scientists who think BIGGER!

    The asteroid, up to 40m in size and only discovered five days ago, passes by on Friday.

    Asteroid set for ‘close’ 43,300 mile flight past Earth on Friday

    Asteroid 2018 CB will pass by at just less than one-fifth the distance between the Earth and the Moon.

    It was first spotted by the Catalina Sky Survey in Tucson, Arizona, a Nasa-funded project to record potentially hazardous asteroids.

    However, while the pass is relatively close in astronomical terms, it’s nowhere near enough to be a threat.

    The 15-40m space rock is set to make its closest approach to Earth at 22:27 GMT.

    “Although 2018 CB is quite small, it might well be larger than the asteroid that entered the atmosphere over Chelyabinsk, Russia, almost exactly five years ago, in 2013,” said Paul Chodas, manager of Nasa’s Center for Near-Earth Object Studies.

    Eyewitnesses and CCTV cameras capture the 2013 Chelyabinsk asteroid

    “Asteroids of this size do not often approach this close to our planet – maybe only once or twice a year.”

    CB 2018 will buzz us at a distance of 69,700km (43,300 miles), which is roughly twice as far as the belt of satellites which orbit Earth in geostationary orbit.

    Another small asteroid passed within lunar distance this week.
    Known as 2018 CC, the object made its closest approach to Earth on 6 February at a distance of about 184,000km (114,000 miles).

    That asteroid, also discovered by the Catalina Sky Survey, was estimated to be between 15m and 30m (50-100ft) in size.

    “Big guns” are feeble in comparison to the Solar System throwing stones at tens of thousands of mph!

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