428-Phaethon

The mysterious Earth approaching object Phaethon does not fit neatly into our definition of either an asteroid or a comet.During it's close approach to Earth in December of 2017 the Arecibo Observatory, having just recovered from hurricane Maria, used the unique combination of it's giant 1,000 foot diameter dish and RADAR transmitting capability to ping Phaethon to obtain images with the RADAR signals it reflected back to us.