Experts noticed Earth had a small companion in its orbit last month, in what was described as a second moon, or a minimoon. When we think of Earth’s Moon, we imagine the bright white ball that helps to illuminate the night sky. However, the definition of a moon is a natural satellite that is captured by a planet’s gravitational pull.
So when experts say the Earth has more than one moon, they do not necessarily mean there are two or more of the giant white rocks in the sky.
What they actually mean is Earth has pulled in small asteroids that are now caught in its orbit.
On occasion, these minimoons can fall into Earth’s atmosphere, producing a fireball as they do.
Experts believe Earth recently caught another small moon, about the size of a car, and pulled it into its orbit.
But the meteor, known as 2020 CD3, is expected to leave Earth and make its way across the cosmos once more.
Experts believe it will leave Earth’s orbit within a few weeks, as it is barely visible now.
Bill Gray, whose software helped astronomers pinpoint the minimoon’s location, told the Atlantic: “Unfortunately, we are catching this one on its way back out.
“It’s getting fainter. Already, it’s faint enough that if the Catalina Sky Survey looked at it now, it wouldn’t see it.”
In 2012, scientists used a supercomputer to run simulations on the movements of 10 million near-Earth asteroids that pass our planet.
They ran these simulations against the trajectory of 18,000 space rocks that have been pulled into Earth’s orbit.
Results showed at least one mini-asteroid, usually measuring no more that three feet in diameter – virtually nothing compared to the 2,000 mile diameter Moon – is circling our planet at any given time.
The asteroids are usually caught up in Earth’s orbit for about nine months before they continue their normal orbit around the sun, but the team say they can get stuck there for decades.
The minimoons do not have a normal orbit though – the simulation also revealed they twist and turn under the gravitational influence.
In 2016, a minimoon came crashing into Earth, producing a fireball as it did.
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Asteroids and meteors produce a bright explosion of fire when they hit the atmosphere as it is the first time the space rock has ever met resistance.
Air seeps into the pores and cracks of the rock, pushing it apart and causing it to explode.
The IMO said: “Fireballs are meteors that appear brighter than normal.
“Due to the velocity at which they strike the Earth’s atmosphere, fragments larger than one millimetre have the capability to produce a bright flash as they streak through the heavens above.
“These bright meteors are what we call fireballs and they often strike fear and awe for those who witness them.”
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