An enormous asteroid, with an estimated diameter of between 460 and 1,050 feet, is on course for a close encounter with Earth in 2023. At 0:30 a.m. on October 17, the cruise ship-sized space rock will make its closest approach to Earth since records began.
We are talking relatively here: "close" in universe terms is still hundreds of thousands of miles away. In this case, asteroid 1998 HH49 is expected to come within 730,000 miles of our planet, which is about three times the distance between the Earth and the moon.
Using mathematical models, NASA has estimated that the asteroid will not be as close to Earth again until the year 2163, when it will come within approximately 400,000 miles.
Asteroid 1998 HH49 last approached Earth in 2021 but it was over 40,000,000 miles away. It is next expected to approach the Earth in 2025 and 2027 but again it will be tens of millions of miles away.
"Asteroids are 'bits of a planet that didn't happen' that orbit the sun between Mars and Jupiter in the main asteroid belt," Jay Tate, the director of the U.K.'s Spaceguard Center observatory, previously told Newsweek. "However, as they are relatively small, asteroids can be disturbed quite easily, so they can develop orbits that cross those of planets."
In other words, the orbit of an asteroid can be nudged by the gravitational attraction of other planets which can drag them down into the inner solar system and close proximity with Earth. These asteroids are often described as Near-Earth Objects (NEOs).
When these asteroids come within 4.6 million miles of the Earth's orbit and measure over 460 feet in diameter, they are classed as "potentially hazardous" objects, as is the case for 1998 HH49.
However, this classification does not make these asteroids an immediate threat.
"The potentially hazardous designation simply means over many centuries and millennia the asteroid's orbit may evolve into one that has a chance of impacting Earth," Paul Chodas, manager of NASA's Center for Near-Earth Object Studies, previously told Newsweek.
NASA's NEO Earth Close Approaches database has identified over 30 of these "potentially hazardous" asteroids that will approach Earth in the coming year. But most of these will still be millions of miles away. The closest approach after 1998 HH49 will be from asteroid 2011 AG5, which measures between 360 and 820 feet in diameter and is expected to come within 1.1 million miles of Earth.
Two asteroids are expected to come even closer to Earth than 1998 HH49. The closest, asteroid 2020 DG4, is predicted to come within 340,000 miles of our planet. However, it is much smaller than 1998 HH49, measuring only 20 to 46 feet in diameter.
While these asteroids are approaching "close" in universe terms, NASA's Planetary Defense Coordination Office says that there is still very little chance that any of them will hit our planet in the next century.
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Uncommon Knowledge
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Newsweek is committed to challenging conventional wisdom and finding connections in the search for common ground.
About the writer
Pandora Dewan is a Senior Science Reporter at Newsweek based in London, UK. Her focus is reporting on science, health ... Read more
