 The comet did not come much closer to Earth than 300 million km, which prevents using radar to directly determine its size and shape.This could be done using the occultation of a star by 2I/Borisov but an occultation would be difficult to predict, requiring a precise determination of its orbit, and the detection would necessitate a network of small telescopes.A study using observations from Hubble could not find a variation in the light curve.