A newly discovered asteroid designated 2017 OO1 flew past Earth at a very close distance of 0.33 LD (~125 720 km / 78 740 miles) at 02:27 UTC on July 21, 2017. It was discovered 2 days after its closest approach.
This is the 25th known near-Earth asteroid to flyby Earth within 1 lunar distance since the start of the year. The last time one flew past us within that distance was on May 4.
Asteroid 2017 OO1 belongs to the Aten group of asteroids and was first observed at ATLAS-MLO, Mauna Loa, Hawaii on July 23, 2017.
Its estimated diameter is between 35 to 77 m (115 - 252.6 feet) and it flew past Earth at a speed (relative to the Earth) of 10.36 km/s.
For comparison, asteroid that exploded some 29.7 km (18.5 miles) above Russian city of Chelyabinsk at 09:20 YEKT (03:20 UTC) on February 15, 2013, damaging over 3 000 buildings and injuring over 1 500 people (mostly by broken window glass), had an estimated size of approximately 20 m (65 feet). Its light was brighter than the Sun, visible up to 100 km (62 miles) away.
Chelyabinsk asteroid, officially named Chelyabinsk meteorite, was undetected before its atmospheric entry, in part because its radiant was close to the Sun.
Check your speakers. Loud asteroid explosion on video.
In the hours following the visual meteor sighting, a 6-metre (20 feet) wide hole was discovered on Lake Chebarkul's frozen surface and scientists from the Ural Federal University collected 53 samples from around the hole the same day it was discovered.
A large number of small meteorites fell on areas west of Chelyabinsk and local residents and schoolchildren located and picked up some of them, many located in snowdrifts, by following a visible hole that had been left in the outer surface of the snow.
In June 2013, Russian scientists reported that further investigation by magnetic imaging below the location of the ice hole in Lake Chebarkul had identified a 60 cm (2 feet) wide meteorite buried in the mud at the bottom of the lake. Following an operation lasting a number of weeks, it was raised from the bottom on October 16, 2013. With a total mass of 654 kg (1 442 lb), this is the largest found fragment of the Chelyabinsk meteorite.
In November 2013, a video from a security camera was released showing the impact of the fragment at the Chebarkul Lake. From the measured time difference between the shadow generating meteor to the moment of impact, scientists calculated that this meteorite hit the ice at about 225 meters per second, 64 percent of the speed of sound.
This is the first recorded impact of a meteorite on video. You can see it below:
Video shows the first recorded impact of a meteorite. Chelyabinsk, Russia February 15, 2017
Featured image: Asteroid 2017 OO1 geocentric flyby diagram. The green line indicates the object's apparent motion relative to the Earth, and the bright green marks are the object's location at approximately one hour intervals. The Moon's orbit is gray. The blue arrow points in the direction of Earth's motion and the yellow arrow points toward the Sun. Credit: Minor Planet Center