A rather sizeable asteroid -- one thought to be large enough to potentially dwarf the Leaning Tower of Pisa in Italy -- is hurtling through space on its way to Earth and will dash by for a short visit on Thursday night, NASA has announced. Known as asteroid 2019 WB5, tomorrow's celestial visitor is part of a larger group of recently discovered asteroids that are due for close visits in the upcoming days. The rock may not venture as close as the tiny 59-foot asteroid that will skim the planet on Friday at just a couple of times the distance to the moon. However, it will still come close enough for NASA to keep tabs on its trajectory to make sure that its impeding flyby of Earth will be a harmless one.
According to a report issued last week by NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, the wayfaring space rock was first spotted on November 27. NASA scientists have spent three days monitoring the asteroid's orbital path in order to plot its course through the inner solar system and establish how close it will get to Earth. As NASA explains, the orbit of an asteroid is calculated by taking precise measurements of its position as it cruised across the sky. Those measurements, derived from direct observations, are then compared to computer simulations of the object's orbit around the sun for an even higher accuracy. Data gathered on asteroid 2019 WB5 showed that the object will be making a close but perfectly safe approach to Earth, buzzing the planet from a few million miles away.
Barreling through the void of space at break-neck speeds of more than 49,000 mph, the asteroid is expected to swoop in for its close encounter with Earth at 10:02 p.m. ET. As it does so, the rock will come as close as 4.4 million miles from the planet's surface. To put that into perspective, that's 18.61 times the distance between Earth and the moon.
Following its close approach to Earth, the swift asteroid will exit the inner solar system and continue its orbit around the sun. Interestingly enough, tomorrow's flyby will be the first time that asteroid 2019 WB5 passes through our corner of space. The rock orbits the sun once every 1,152 days, or a little over three years, but it has never journeyed through our corner of the solar system before. The object is not likely to return, thereby making tomorrow's flyby its first and only visit of Earth.
Size-wise, asteroid 2019 WB5 is not at all negligible. The object is among the larger space rocks to traipse through our cosmic neighborhood in recent weeks. The asteroid is estimated to be at least 118-feet across and can measure up to 262 feet in diameter, per NASA's Center for Near-Earth Object Studies (CNEOS). At the upper end of that size estimate, the rock is 1.4 times bigger than the Tower of Pisa.
As impressive as that may be, the asteroid pales in comparison to the huge 560-foot-wide chunk of rock due to shoot past Earth the following day. More close asteroid approaches are expected to occur during the weekend.