Most distant planetary flyby in history

Most distant planetary flyby in history

The NASA probe captured photographs of the distant object

Three years ago, NASA’s New Horizons probe made its famous flyby of the dwarf planet Pluto. On New Year’s day 2019, the probe made history again, in its flyby of Ultima Thule. This is the farthest away object humanity has ever visited in the Solar System, 6.5 billion km away from the Earth. Flying as ‘close’ to the object as 3,500km, New Horizons took a series of stunning photographs and collected a variety of scientific data. At this distance, the radio signals took over six hours to return to Earth. On seeing the images, New Horizons principal investigator Alan Stern described Ultima Thule’s shape as a ‘snowman’. Significant observations recovered include that the body has much fewer craters than an object of its size would in the inner solar system. This might mean the undeformed surface would preserve evidence of the objects original accretion during solar system formation 4.6 billion years ago. Also notable is the object’s red colour, which is suggestive of organic compounds. The total downlink of data collected from the flyby is expected to last 20 months, through to September 2020.

Seán Thór Herron is a 4th year student of Earth Sciences at Magdelene College and President of BlueSci. Image: artist’s impression of NASA’s New Horizons spacecraft encountering 2014 MU69 on Jan. 1, 2019. Image Credit: NASA/JHUAPL/SwRI