The mountain-sized 2014 JO25 asteroid safely avoided Earth in its close flyby on April 19 but left behind a heap of data for researchers to analyze.
Besides sparking avid discussions on how humanity would perish in a big asteroid collision, the event provided astronomers with the perfect opportunity to study the enormous space rock and gather as much information as possible on the general characteristics of asteroids.
This week's asteroid encounter marked 2014 JO25's closest approach to our planet in 400 years and the nearest it will come to Earth in the next half millennium. The asteroid passed by us at a distance of 1.1 million miles, or about 4.6 times the trip from Earth to the moon.
A day before its closest approach, NASA's Goldstone Deep Space Communications Complex in California captured footage of 2014 JO25 via deep space radar, revealing the asteroid's size, structure, and shape, as well as the space rock's traveling speed and rotation.
This data, obtained in the early morning of April 18 with Goldstone's 70-meter (or about 230-foot) antenna, was extremely useful in determining 2014 JO25's orbital path and calculating the asteroid's likelihood of hitting Earth.
April 19 Asteroid First Spotted In 2014
First detected in 2014 (as its name suggests) by A. D. Grauer from the Catalina Sky Survey, a project conducted under NASA's Near-Earth Objects Observations Program, the asteroid's non-hazard status was established as early as three years ago.
"We discovered 2014 JO25 on the night of May 4, 2014, using our 1.5-meter [or 4-foot] survey scope on top of Mt. Lemmon," says Eric Christensen, director of the Catalina Sky Survey.
At the time, researchers passed the data to the Near-Earth Objects program to get a clearer picture of where and how close the space rock was, "so other astronomers can prepare to aim their telescopes and radars to collect data."
The program, also known as "Spaceguard," analyzes the physical features of near-Earth objects and predicts their orbit in order to pinpoint whether they are potentially hazardous to our planet.
The data collected from the space rock's latest flyby — which was close enough to gather asteroid radar imagery — will offer more insight into 2014 JO25's return period.
2014 JO25's Journey Near Earth: The Movie
The Goldstone antenna gathered 30 images of 2014 JO25 passing in the vicinity of our planet, which were later compacted into a video unveiling the asteroid's shape and spin.
"The images reveal a peanut-shaped asteroid that rotates about once every five hours," shows a news release by NASA's Jet Propulsion Laboratory in Pasadena, California.
"The asteroid has a contact binary structure — two lobes connected by a neck-like region," says Shantanu Naidu, the JPL scientist who led the Goldstone observations. "The images show flat facets, concavities, and angular topography," he adds.
Researchers explain the asteroid's two-lobed shape is due to loose material on the rock's surface, which formed another asteroid that temporarily orbited 2014 JO25 before morphing into one giant cosmic rock. This process is common to about 15 percent of asteroids bigger than 656 feet in diameter.
The grid of 30 radar images, captured when the asteroid was 1.9 million miles from Earth, shows 2014 JO25's largest lobe to be around 2,000 feet in diameter.
Astronomers were also able to observe the asteroid's spinning pattern, induced by solar photons. By analyzing the disruption the photons cause in the rock's trajectory, researchers can tell if 2014 JO25's next flyby will be as safe as the last one.