A Close Encounter: The 2,000-Foot-Wide Asteroid 2013 NK4 Sails Past Earth

In a remarkable celestial event, the asteroid known as 2013 NK4 recently made its closest approach to Earth, cruising past at a distance of about eight lunar distances. This 2,000-foot-wide space rock, large enough to be classified as a “potentially hazardous” object, fortunately poses no immediate threat to our planet. This encounter is not just a routine pass; for the first time, this “city-killer” asteroid has come close enough to be observable by amateur astronomers with just a backyard telescope. Over the next few days, sky watchers have a unique opportunity to observe a significant near-Earth object that is typically elusive to the casual observer.

The Details of the Encounter

On April 15, at 10:50 a.m. EDT, 2013 NK4 reached its minimum distance from Earth, approximately 2 million miles away. It was traveling at a significant speed of about 37,000 mph. This asteroid is notable for its size, measuring roughly 2,000 feet wide, which is about twice the size of another well-known asteroid, Apophis. Apophis is projected to make a super close approach to Earth in 2029.

Observational Opportunities

The proximity of this asteroid provides a unique opportunity for both professional and amateur astronomers to observe and study a sizable near-Earth object. Over the next three days, particularly on April 16 and April 17, the asteroid will be optimally positioned for observation due to its orientation relative to Earth. Those interested can track the asteroid’s path and find the best times for observation using astronomy websites like TheSkyLive.com.

Scientific Significance

Astronomers are using this close approach to gather more data on 2013 NK4, employing radio telescopes to capture specialized radar images. These delay-Doppler images will help scientists better understand the asteroid’s size, shape, and surface properties. Such observations are crucial as they contribute to ongoing efforts to monitor near-Earth objects and assess potential threats.

Historical and Future Context

Since its discovery in 2013, this asteroid has made 11 close approaches to Earth, with this encounter being the closest in over a century. Simulations tracing the asteroid’s trajectory back to 1900 confirm this record proximity. Looking ahead, the asteroid is expected to make an even closer approach in 2055, when it will come within about 1.3 million miles of Earth, less than six lunar distances.