As Cassini spacecraft made its Tuesday pass among its 22 scheduled flyby to Saturn successful, a surprising turn of events had resulted. The spacecraft was reported to plunge into the “big empty” region of Saturn and dust particles didn’t turn out the way scientists had predicted.

According to Fox News, NASA’s Cassini probe had flown to the unexplored region of the space between Saturn and its rings called as the “big empty.” Scientists then stated that the region harbors a few hazardous particles. But, the report from the flyby that occurred last Tuesday surprised scientists.

With that said, it was mentioned that Cassini probe had put into use its 13-foot (4-meter) high-gain dish antenna to serve as a shield against dust particles expected from the “big empty” region. However, the outcome wasn’t as expected by scientists. The second pass of the spacecraft revealed that there are fewer dust particles present compared to expectations due to the first flyby of Cassini to Saturn.

The Cassini probe traversed the Saturn’s “big empty” at a relative velocity of about 77,000 mph (124,000 kilometers per hour) as identified in the report. “Cassini will stay the course, while the scientists work on the mystery of why the dust level is much lower than expected,” Earl Maize, Cassini project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California stated.

Aside from that, data recorded from the few dust particles accumulated by the Cassini probe was turned into audio format through the spacecraft’s Radio and Plasma Wave Science (RPWS). The outcome resulted into sounds of popping and cracking sounds as the dust particles from the “big empty” hit the spacecraft as Space Flight Now reported.

William Kurth, RPWS team lead at the University of Iowa, Iowa City then identified that the results from the “big empty” dive differ compared from the first dive of Cassini. The scientists indeed expected to hear loud sounds but received quieter sounds instead. It was also added by NASA in a statement that the dust particles were not bigger than a particle of smoke.

The Cassini Grand Finale’s latest dive was into the “big empty” last May 2 and is set to plunge the orbit passing the rings once every week. Finally, the spacecraft bids goodbye on its crashing finale on Saturn’s atmosphere at Sept. 15, 2017.