Asteroid a half mile long about to make closest pass by Earth

The space rock flying by Thursday is thought to be a dead comet as big as the Burj khalifa.

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A asteroid that was once a comet will be flying through the neighborhood this week.


A space rock that could be taller than the tallest skyscraper on Earth is set to whip by our planet this week.

The object, technically classified as Asteroid 2017 YE5, is thought to be a comet that's gone extinct, meaning it's probably dried up and no longer has a distinct tail. 

It will come within 3.7 million miles (6 million kilometers) of Earth on Thursday, which is over 15 times the distance to the moon. This is the closest pass it will make between now and at least 2189 and the closest it's come since at least 1908, according to NASA.

That's also definitely a large enough distance that we shouldn't worry about the possibility of any kind of impact with Earth or the moon, but 2017 YE5 is still considered a "potentially hazardous" asteroid due to its size.

NASA radar observations estimate the former comet could be up to 860 meters in diameter, or more than 2,800 feet. For comparison, the Burj Khalifa in Dubai stands at 2,717 feet. 

Lots of asteroids zip safely by Earth every week, including many that come much closer than this one. But 2017 YE5 is likely one of the five largest objects to come within around 16 lunar distances over the past year. As such, some of our bigger telescopes, like the Arecibo dish in Puerto Rico, may be able to get a glimpse of it this week. Stay tuned...