‘April Fool’s Day’ Comet Passes by Earth at 13 Million Miles

In this image taken March 24, 2017, comet 41P/Tuttle-Giacobini-Kresák is shown moving through a field of faint galaxies in the bowl of the Big Dipper. Image-Chris Schur

In this image taken March 24, 2017, comet 41P/Tuttle-Giacobini-Kresák is shown moving through a field of faint galaxies in the bowl of the Big Dipper. Image-Chris Schur


41P/Tuttle-Giacobini-Kresák, officially named after its three discoverers, or known this year as the April Fool’s Day Comet, passed by our planet at a distance of approximately 13 million miles.

41P was first discovered by Horace Tuttle in 1858, it was determined then that 41P was a periodic comet, (a comet that orbits the sun) but, it was unknown how long its orbit was. It would not be observed again until 1907. But, its re-discoverer, Michael Giacobini, was not aware that it was the same comet observed in 1858.


It was later that Andrew Crommelin determined that the two sightings in 1858 and 1907 were in fact the same comet.  Crommelin, at the time of his determination, announced that the comet would pass by the earth again in 1928 and again 0n 1934. But, it was not observed and it was widely believed that 41P was lost.

Then, in 1951, 41P was discovered yet again by L’ubor Kresák. Kresák tied this discovery to the earlier two sightings, and its orbit time was further refined to 5.4 years per trip.

This year’s pass-by is believed to have been the closest 41P has passed by in at least 50 years and perhaps the closest in 100 years. At 13 million miles, it swung past at about 55 times the distance of the earth to our moon.

During this swing-by, scientists had an opportunity to fill in details on the composition of the comet, such as its coma and nucleus. Scientists will now have a chance to determine the rotational speed, and the structural soundness of the nucleus.

“An important aspect of Jupiter-family comets is that fewer of them have been studied, especially in terms of the composition of ices in their nuclei, compared with comets from the Oort cloud,” said Michael DiSanti of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. 

DiSanti’s team observed the “April Fools Day” Comet from NASA’s Infrared Telescope Facility in Hawaii.