What does this number measure?
The NASA entry describes Arrokoth as having approximate dimensions of 35 × 20 × 10 km. The drawing's width compares the end-to-end length of the two touching lobes. Their much smaller thickness is not this length. The reddish surface detail is an interpretation of New Horizons observations during the flyby on 1 January 2019.
Compare the stated dimensions
The comparison uses the number in each fact sheet: altitude, height, diameter, length or distance, depending on the reference. Two values in metres do not necessarily describe the same property.
Source and limitations
Rounded NASA dimensions; other publications give about 36 km depending on the model and rounding. No metre-level precision is claimed.
Interpretation of Arrokoth and its two contacting lobes. The greatest horizontal length is calibrated; textures and terrain are artistic.