A tiny space rock, one believed to be no bigger than 55 feet wide, will scrape past Earth later today in what NASA has announced to be an extremely close asteroid encounter. Our celestial visitor is known as asteroid 2019 YL3 and will skim Earth from very close by, coming nearly as close as the moon. Its close brush with our planet will also bring the rock within a short distance from our natural satellite, as 2019 YL3 will be performing a close flyby of both Earth and the moon.
The wayfaring space rock is expected to swing by around noon time. According to a report released today by NASA's Jet Propulsion Laboratory (JPL), asteroid 2019 YL3 will first be making a close pass by the moon. The object will cruise by at 11:16 a.m. ET, flying at speeds of up to 24,500 mph. As it does so, the asteroid will creep in as close as 651,000 miles from the moon's cratered surface.
A few hours after its lunar flyby, the rock will make its close approach to Earth, buzzing our planet from an even shorter distance. NASA predicts that the asteroid will fly past Earth at 1:39 p.m. ET, traveling at speeds of 22,450 mph. As it reaches its closest point to Earth, the object will be only 409,200 miles from our planet. By comparison, the moon sits at an average distance of about 238,900 miles from Earth. This means that the asteroid will come within 1.74 times the lunar distance when it swoops by later this afternoon.
Interestingly enough, today's approach marks the asteroid's first pass through the Earth-moon system in a little over half a century. The last time the rock ventured through our neck of the cosmic woods was 53 years ago, in late November 1966. At the time, the asteroid only managed to get some 35 million miles from the planet's surface -- a staggering distance compared to today's close approach. That particular encounter was also the asteroid's first flyby of Earth, per JPL data. A few years after that, the rock made a close pass by the gas giant Jupiter as it trekked the outer solar system in its journey around the sun.
Perhaps the most striking thing about asteroid 2019 YL3 -- other than its close proximity to Earth, that is -- is that it almost slipped past NASA's radar. The near-Earth asteroid was discovered just two days ago and has been attentively monitored by the JPL in an effort to determine how close it will get to Earth. After carefully calculating its orbit, the team established that the rock circles the sun once every 4.8 years and follows an orbital path consistent with that of Apollo asteroids. This means that the object can not only approach Earth, but also cross the planet's orbit.
As NASA explains, the orbit of an asteroid is calculated "by comparing measurements of its position as it moves across the sky to the predictions of a computer model of its orbit around the sun."
"The more observations that are used and the longer the period over which those observations are made, the more accurate the calculated orbit and the predictions that can be made from it," notes the space agency.
In the case of asteroid 2019 YL3, JPL scientists performed a total of 30 observations over the past couple of days since the rock was spotted. The asteroid is not expected to return anytime soon.