Potentially-Hazardous Asteroid Makes Closest Approach to Earth, Can Be Visible for the First Time Through Amateur Telescopes

A "city-killer" asteroid has just made its closest approach to our planet since records began. Although it is classified as "potentially hazardous," the massive space rock does not pose any threat to Earth.

A Close Encounter

The hefty asteroid, named 2013 NK4, sailed safely past the Earth at more than eight lunar distances, or the average distance between the Earth and the moon. According to NASA's Jet Propulsion Laboratory (JPL), the asteroid made its closest approach to Earth at 10:50 a.m. EDT Monday (April 15). At the time, it reached around 2 million miles (3.2 million kilometers) from the Earth while traveling at a speed of about 37,000 miles per hour (59,000 kilometers per hour).

Based on NASA's calculations, 2013 NK4 will likely never come close to impacting Earth. However, due to its size and proximity to our planet, it is still considered a potentially hazardous asteroid.

Although 2013 NK4 does not pose any threat to Earth, its close approach is still of great interest to scientists who are currently monitoring the space rock with radio telescopes. They are hoping to capture specialized radar images, called delay-Doppler images, which can help them gain more information on the space rock's size and shape.

Fortunately, skywatchers do not have to be professional astronomers to peek at the 2013 NK4. The celestial body will be visible to anyone with a decent astronomy telescope until April 17. However, because of its orientation relative to Earth, the space rock will be most clearly visible on April 16 and April 17.

City Killer

The celestial body is about 2,000 feet (610 meters) wide, making it twice the size of the "god of chaos" asteroid Apophis, which is expected to make a super-close approach to our planet in 2029.

If it were to hit our planet, this asteroid would be large enough to destroy a large city and cause serious environmental impacts. It also orbits the Sun on an elliptical orbit every 378 days.

Since 2013 NK4 was first discovered, it has made 11 close approaches to Earth and will likely return for another. According to the JPL Small-Body Database, this asteroid will make a more distant flyby on April 23, 2025. However, the 2013 NK4 has never been spotted close enough to be seen with a backyard telescope until now.

Simulations of the space rock's trajectory retraced its orbit around the Sun as far back as 1900. They show that its latest flyby to Earth is also its closest approach in at least 125 years. However, the same simulations reveal that 2013 NK4 will make an even closer approach in 2055 when it reaches a minimum distance of around 1.3 million miles (2.1 million kilometers) from the Earth or less than six times the average distance between Earth and the moon.

The simulations also show that 2013 NK4 also makes close approaches to Venus. Astronomers believe that this asteroid will not hit Venus for at least the next 100 years.

Check out more news and information on Asteroids in Science Times.