A few Clarence Shepard Day Jr. ago , the largest asteroid in more than a centuryflew past Earth . During the result , astronomer made a surprising find – the asteroid had two previously unseen moons .
Called 3122 Florence , named after Florence Nightingale , the asteroid measured about 4.5 kilometers ( 2.8 mile ) across . Although many asteroids vaporize past Earth every twelvemonth , this was the biggest to fly near Earthsince 1890 .
Firenze flew past at a length of about 7 million kilometers ( 4.4 million miles ) . That ’s about 18 times the distance between Earth and the Moon , so thankfully it posed no threat to us . It ’s a admonisher , though , of the issue of potentially crushing asteroids that pass our planet every year .
Using radar images captured by NASA ’s Goldstone Deep Space Communications Complex , scientist chance two extra object orbiting with the asteroid as it swung past . Their sizes are n’t sure , but it ’s thought they ’re both about 100 to 300 meters ( 300 to 1,000 metrical foot ) across .
This is only the third asteroid with two moons we ’ve discover in the 16,400 near - land asteroids so far . The last “ treble asteroid ” was seen back in June 2009 , called asteroid 1994 cubic centimetre .
“ The radar figure of speech also provide our first close - up eyeshot of Florence itself , ” suppose NASA in astatement .
“ 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 humble - ordered series topographical features . The images also substantiate that Florence rotates once every 2.4 hour , a result that was determine previously from optic measurements of the asteroid ’s brightness variations . ”
Florence , discovered in 1981 , is now continuing its journey off from our planet . It ’s hoped that radar datum from other observations may reveal more about the moons . The asteroid completes an range around the Sun every two years and four month , traveling out to a distance beyond Mars . But it wo n’t fell past worldly concern again until 2050 . So it ’s a just thing we spotted its moons this clock time around .
