NASA Tracking 'Potentially Hazardous' Empire-State—Sized Asteroids Incoming

Two enormous "potentially hazardous asteroids" are due to soar through Earth's neighborhood later this week. Both are classed by the Jet Propulsion Laboratory's (JPL) Center for Near-Earth Studies (CNEOS) as near-Earth objects (NEOs) and as potentially hazardous asteroids (PHAs). NEOs are defined as any object that comes within approximately 120 million miles of the sun, or 30 million miles of Earth, while a PHA is classed as an object measuring at least 460 feet in diameter that approaches within about 4.6 million miles from the sun.

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The asteroids, named 447755 (2007 JX2) and (2020 XR), are each estimated at being around the size of the Empire State Building. The NASA-owned JPL says they are likely to be 1,300 feet and 1,200 feet across, respectively. However, CNEOS estimates that 447755 (2007 JX2) may measure between 984 feet and 2,198 feet, and that 2020 XR potentially has a diameter of between 951 feet and 2,133 feet. For comparison, the Empire State Building is about 1,250 feet tall, the Eiffel Tower stands at around 1,060 feet, and the One World Trade Center towers above both at 1,776 feet.

The asteroids are due to soar near our planet on December 3 and 4 respectively, with 447755 (2007 JX2) passing at a distance of 3,440,000 miles, and (2020 XR) passing at 1,370,000 miles. For perspective purposes, the moon orbits our planet at a distance of 238,900 miles, while our closest planet companion, Venus, is about 24 million miles away at its closest point. "A potentially hazardous asteroid (PHA) is one that has an orbit intersecting the Earth's orbit around the Sun by less than 0.05 astronomical units (1 AU is the distance to the Sun), that's just over 4.5 million miles," Martin Barstow, a professor of astrophysics and space science at the University of Leicester in the U.K., previously told Newsweek. "It also has to have an absolute brightness of 22.0 or less (lower values of the magnitude are brighter = larger objects), i.e. an asteroid (or comet) that would cause significant regional damage if it hit the Earth," Barstow added. "Not all NEOs are potentially hazardous, but all hazardous objects are NEOs." NASA tracks around 36,000 NEOs, and roughly 2,350 PHAs. Both 447755 (2007 JX2) and (2020 XR) originated in the Asteroid Belt between Mars and Jupiter. Jupiter's immense gravity can disturb the orbits of nearby asteroids, and can cause an asteroid to be pulled out of the belt and onto a trajectory that crosses Earth's orbit. Additionally, collisions between asteroids might send an asteroid out of the belt and potentially toward the inner solar system. Thankfully, neither of these asteroids really pose any threat to our planet, despite their frightening-sounding PHA classification. NASA keeps an eye on every large asteroid that comes even slightly close to our planet to make sure they steer well clear of us. "The more we observe [asteroids], the better our calculations are for predicting future close-approaches," Gretchen Benedix, an astrogeologist at Australia's Curtin University, told Newsweek. If an asteroid the size of these two visitors did ever collide with our planet, we would be in for a very bad time indeed. "An asteroid 100-200 meters [330-650 feet] in diameter would cause a regional disaster, taking out a small country but with the resulting global consequences in terms of the global economy and globalization," Jay Tate, director of the Spaceguard Centre observatory in the U.K., previously told Newsweek. There are three other smaller asteroids passing our planet this week. The house-sized 2024 WN4 and bus-sized 2021 XZ will zip past on December 2 at distances of 1,100,000 miles and 3,140,000, respectively, while the 60-foot 2024 WL6 will pass at 937,000 miles on December 3. Do you have a tip on a science story that Newsweek should be covering? Do you have a question about asteroids? Let us know via science@newsweek.com.