An asteroid that passed within 3.7 million miles from Earth last year has turned out to be not one object, but two.
Asteroid 2017 YE5 was first spotted on Dec 21, 2017 by the Morocco Oukaimeden Sky Survey, and made its closest approach to Earth last month, on June 21.
Observations during its close flyby, when it was about 16 times the distance between Earth and the moon, revealed it to be a binary system made up of two 3,000-foot objects orbiting each other.
NASA has released what it says are the most detailed images taken yet of the near-Earth system, revealing how the two space rocks dance around each other.
The experts say the binary asteroid won’t come this close to Earth for another 170 years.
While it’s clear from the latest observation that 2017 YE5 is, in fact, two objects, it’s easy to see how it could be mistaken for one at some angles.
When viewed head on at certain points in their orbits, the two align to appear as a single, albeit lumpy, space rock.
While it’s clear from the latest observation that 2017 YE5 is, in fact, two objects, it’s easy to see how it could be mistaken for one at some angles. The image above shows one of the first observations
‘On June 21 and 22, observations by NASA’s Goldstone Solar System Radar (GSSR) in California showed the first signs that 2017 YE5 could be a binary system,’ NASA explains.
‘The observations revealed two distinct lobes, but the asteroid’s orientation was such that scientists could not see if the two bodies were separate or joined.
‘Eventually, the two objects rotated to expose a distinct gap between them.’
Further observations at the Arecibo Observatory in Puerto Rico and the Green Bank Observatory in West Virginia independently confirmed the discovery.
According to NASA, the two asteroids have a number of unique characteristics.
Unlike typical rocky asteroids, they are ‘as dark as charcoal,’ meaning they don’t reflect as much light.
It’s also thought they may differ in density, surface composition, or roughness, as the team found ‘striking differences’ in radar reflectivity between the two.
This, NASA says, has never been seen the more than 50 other binary systems studied in the last 18 years.
And, it’s even rarer considering the large size of each object.
‘Contact binaries, in which two similarly sized objects are in contact, are thought to make up another 15 percent of near-Earth asteroids larger than 650 feet (200 meters) in size,’ NASA says.
Researchers say the discovery could help us to understand these unusual systems and how they form.
HOW IS NASA STEPPING UP ITS EFFORTS TO STOP DEADLY ASTEROIDS HITTING EARTH?
The US government is stepping up efforts to protect the planet from incoming asteroids that could wipe out entire regions or even continents.
The National Science and Technology Council released a 20-page report on June 21 calling for improved asteroid detection, tracking and deflection.
The initiative backed by Nasa, federal emergency officials, and the White House aims to coordinate efforts over the next 10 years to detect and respond to possible threats in Earth’s vicinity, should they arise.
Near-Earth objects (NEOs) include all asteroids and comets that orbit within 30 million miles of Earth, Nasa said.
The U.S. government is stepping up efforts to protect the planet from incoming asteroids that could wipe out entire regions or even continents (stock image)
While the probability of an asteroid impact may be low, the effects could be cataclysmic.
For now, scientists know of no asteroids or comets heading our way. But one could sneak up on us – and that’s why the government wants a better plan.
Nasa’s planetary defense officer, Lindley Johnson, says scientists have found 95 percent of all near-Earth objects measuring one kilometer (two-thirds of a mile) or bigger.
But the hunt is still on for the remaining five per cent and smaller rocks that could still inflict big damage.
The new document, titled ‘The National Near-Earth Object Preparedness Strategy and Action Plan,’ established five strategic goals to reduce the risk of an asteroid strike.
These included better methods for detecting and tracking the objects, improved modelling, the development of technologies to deflect NEOs, increased international cooperation on the subject, and the establishment of emergency procedures.