Scientists revealed an asteroid dubbed by some as a "city killer" came closer to the Earth than the moon this week.


The Washington Post reported that scientists apparently had no idea it was coming.


Asteroid 2019 OK came hurtling toward Earth at a speed of nearly 15 miles a second, before flying past.

小行星2019 OK以接近15英里/秒的速度飛奔向地球,然后從地球邊掠過。

According to NASA, it was about 45,000 miles from Earth on July 25.


"It would have hit with over 30 times the energy of the atomic blast at Hiroshima," astronomer professor Alan Duffy told the Sydney Morning Herald.

天文學教授Alan Duffy對《悉尼先驅晨報》說:“撞擊威力超過廣島原子彈爆炸能量的30倍”。


Duffy called the zooming space rock a "city killer."


Astronomers say it posed no immediate threat but they admit they had no idea the giant rock was headed our way, because it came from the direction of the sun.


The asteroid, about the size of a large boulder, only became visible a few days ago.


There are 20,000 near-Earth asteroids and they do occasionally make an appearance. In 2013, one slammed into Russia, injuring 1,600 people.????


At a conference in April, scientists from around the world were asked how to respond to a make-believe scenario in which an asteroid big enough to destroy a major city might be on track to strike the Earth in eight years.


The likely response would be using space ships to give the asteroid a nudge, one scientist said.


"All we have to do is change its speed a little faster or a little slower so that when it crosses Earth's orbit, it crosses either in front of us or behind us," said Dr. Lori Glaze, director of planetary science at NASA.

NASA行星科學部負責人Lori Glaze博士說:“我們需要做的就是將其速度變快一點或變慢一點,讓其經過地球軌道時要么往前偏一點,要么往后偏一點”。