One of NASA’s goals for the future is to capture an asteroid and bring it into orbit around Earth or the moon. However, scientists have just spotted an asteroid that has been in orbit around Earth for the last 50 years. We just didn’t notice it until now. So, good job, everyone. Mission accomplished.
The asteroid is known as 2016 HO3, and was detected on April 27th, 2016 by the Pan-STARRS 1 asteroid survey telescope in Hawaii. While it loops around Earth in a relatively stable orbit, it’s also heavily influenced by the sun. 2016 HO3 has a highly elliptical orbit, and it’s much further out than the moon. It never gets closer to Earth than 9 million miles (14 million kilometers). The moon is only 239,000 miles away. So, the good news is that 2016 HO3 is never going to hit us.
The space rock itself is just between 120 and 300 feet across. Its composition is currently unknown. The small size and extreme distance explains why it wasn’t spotted until just recently. However, it’s been in this orbit for over 50 years, based on orbital calculations. Scientists also expect that 2016 HO3 will remain in orbit of Earth for at least a few more centuries. A similar asteroid was spotted in orbit of Earth in 2003, but it only remained in our vicinity for about a decade before it broke free. 2016 HO3 is much more stable.
So, does this mean Earth has a new moon? NASA says 2016 HO3 would be more accurately classified as a quasi-satellite because of its extreme and variable distance from Earth. This makes it a poor target for study in its current orbit, thus NASA’s asteroid redirect mission is still on the books.