- About Richard
I took this series of five five-minute image of asteroid 1981ET3 (“Florence”) at its closest approach to planet Earth on September 1, 2017, when it was 4.4 million miles (18 Earth-Moon distances) away in the constellation Aquarius and near the star HIP 104557. The asteroid appears as a small white “line” in the center of the image.
Florence is 2.7 miles in diameter (30 Egyptian pyramids, according to NASA) and was discovered in 1981 at the Siding Spring Observatory in New South Wales, Australia (an observatory hosting several telescopes that I regularly operate, robotically). It is the largest known asteroid to have passed so close to Earth since NASA began tracking large asteroids.
Florence, named after the famed nurse, Florence Nightingale, will make a closer pass to Earth in the year 2500.
According to NASA, a collision between an object the size of Florence and planet Earth would result in a “high global impact,” and likely occurs once every 6 million years.