Asteroid fly-by of Earth

Just-discovered Asteroid Near-Misses Earth, Passes Through Cloud of Satellites

Another near-miss asteroid zipped past Earth on April 4, well within the orbit of our geosynchronous satellites and half the distance of the semi-synchronous satellites orbiting the planet. In fact, according to NASA, the “car-sized” asteroid, designated 2017 GM, “whipped” by Earth at a negligible (relatively speaking) 10,100 miles. As frightening as the thought might be that an asteroid came so close to Earth, it should be noted that the hurtling space rock was discovered only the day before.

Scientists at the Mount Lemmon Survey in Arizona were the first to spot asteroid 2017 GM on April 3, according to Space. Astronomers at the Virtual Telescope Project and Tengara Observatories (also in Arizona) were able to visually capture the speeding 12-foot space rock, photographing it as it zipped by at 11.5 miles per second (41,400 miles per hour). The photo was taken just before the asteroid reached its closest point to Earth.

NASA’s Jet Propulsion Laboratory (JPL) tracked the asteroid and determined that it has a wide-ranging orbit and passed by Earth on its last go-round in 1961 — but at a far greater distance, some 93 Lunar Distances (LD units, the distance between the Earth and Moon, are measured at 239,228 miles, or 385,000 kilometers), which it roughly 22.25 million miles (36.2 million kilometers) away. The JPL projections contend that the asteroid then traveled way out into the Solar System before returning to inner planets territory, where it flew past the orbits of Mars and Venus a year apart (2013 and 2014, respectively) before enjoying its near-miss fly-by of Earth.

It is unclear if asteroid 2017 GM was bestowed its name as an inside joke by astronomers due to its size or if the “car-sized” description was added by a witty reporter to correspond with the “GM” — a common shortening of the title of the automotive giant General Motors, or, as is true in some cases, the compound adjective appeared in the Space story by coincidence.

According to the JPL, asteroid 2017 GM is the 15th Near-Earth Object (NEO) to pass by just this month. To get an idea of just how many asteroids pass by our planet, a look at the Near-Earth Object Program’s list of “Upcoming Close Approaches To Earth” indicates that nearly four dozen asteroids will pass by between April 7 through April 21. A Near-Earth Object is defined as any small Solar System object that passes within 1.3 Astronomical Units (an AU is equal to about 93 million miles, or 150 million kilometers) of the Sun. The Minor Planet Center, as part of the International Astronomical Union, is operated by the Smithsonian Astrophysical Observatory at Harvard University and tracks over 15,000 NEOs, adding about 30 new NEOs to their list every week.

Asteroid 2017 GM is the closest near-miss NEO to buzz Earth since March when asteroid 2017 EA breached the satellite cordon orbiting Earth and came to within 9,000 miles (14,500 kilometers) of the planet. That space rock was only 10 feet in diameter.

Asteroid makes approach toward the Sun
There are over 15,000 known Near-Earth Objects that have been detected thus far. [Image by Nostalgia for Infinity/Shutterstock]

The actual danger posed by asteroids the size of 2017 GM and 2017 EA is determined by velocity, trajectory, and composition of the object. Most asteroids that enter Earth’s atmosphere are of the smaller variety and tend to burn up as they pass through. Some, being partially composed of denser materials (like iron, for instance), will at times reach the Earth as an impactor, a meteorite, but usually are not large enough (or impact in non-populated areas of the planet) to cause anything but minor damage.

The Chelyabinsk meteor that scorched the skies over Russia in February 2013 was determined to be an object roughly 20 to 30 meters (65-100 feet) in diameter. As it burned away in the upper atmosphere, it detonated with the force of approximately 30 Hiroshima atomic bombs, producing an airburst shockwave that damaged thousands of buildings and sent over a thousand people to the hospital.

Asteroid entering Earth's atmosphere
Several factors determine an asteroid’s danger to the Earth, including velocity, trajectory, and composition. Most, including the undetected objects, fly harmlessly by or are small enough to burn up upon entry into the Earth’s atmosphere. [Image by Vadim Sadovski/Shutterstock]

The Chelyabinsk meteor surprised the world. Unlike 2017 GM or 2017 EA, where there were at least a few hours of advance notice, that asteroid flew undetected from the direction of the Sun.

[Featured Image by Juan Gaertner/Shutterstock]