Three Asteroids to Whizz Past Earth in One Day—And One Will Come Closer Than The Moon

This Saturday, three asteroids will fly by Earth in quick succession, according to data from NASA's Center for Near-Earth Object Studies (CNEOS).

The first of the asteroids (2018 VS1)—which is estimated to be between 43 and 92 feet wide—will come as close as 861,700 miles to the Earth at 9:03 a.m. ET, travelling at speeds of around 23,700 miles per hour relative to our planet, faster than many rockets.

The second space rock (2018 VR1) will make its closest approach just over 15 over minutes later but at a much greater distance—a minimum of 0.03366 Astronomical Units (AU), or 3,128,892 miles. (One AU is equal to the average distance between the Earth and the Sun. or 93 million miles).

2018 VR1 is around the same size as the asteroid proceeding it—albeit slightly larger, measuring somewhere between 46 and 98 feet wide—but it will be moving a little slower.

At 1.26 p.m., the final asteroid, 2018 VX1, will come closest of the three to Earth—potentially as near as 237,037 miles. This may sound like a great distance, but it is relatively paltry in space terms. In fact, this will bring the object just within the average distance between the Earth and the Moon, which is around 238,900 miles.

2018 VX1, is the smallest of the three objects, however, measuring between 26 and 59 feet, and it is also travelling the slowest at "just"13,556 miles per hour.

Near-Earth Objects are any asteroids or comets whose orbits take them within about 121 million miles of the sun and into proximity with the Earth.

If the orbit of a NEO at the time of its discovery is such that there is a (typically small) chance it will collide with Earth and cause significant damage, it is labeled "potentially hazardous," according to the Swinburne Astronomy Online Encyclopedia.

The asteroid, or other object, must have a minimum approach distance of less than 0.05 AU, or roughly 4.6 million miles, to be classified as such, as well as being at least 460 feet in diameter.

An illustration showing a swarm of asteroids. iStock

If an asteroid of this size did crash into our planet it would cause devastation on the scale of entire countries if it struck land, or a major tsunami in the case of an ocean impact

Aside from the massive destruction resulting from the initial impact, the global climate would be affected, leading to widespread crop failures and loss of life, among other effects.

Once potentially hazardous asteroids or other objects are discovered, they are monitored continually by observatories around the world. Over time, their orbits may be disrupted through gravitational interactions with other planets or bodies, increasing or decreasing the risk of a collision.

But even though the orbits of "potentially hazardous asteroids" are uncertain, "it is possible to estimate the size of these uncertainties and place corresponding limits on close-approach distance and time," according to NASA.

In total, the number of known NEOs exceeds 18,000, of which more than 1,800 are considered potentially hazardous. Researchers have detected around 90 percent of NEO's larger than a kilometer in size, none of which are predicted to collide with Earth. There are, however, thought to be many NEOs smaller than this that are currently unaccounted for.