A Large Asteroid Will Pass by Earth This Week – Is It a Threat to the Planet?

Recent weeks have witnessed a series of medium-to-large-sized asteroids cross paths with Earth’s orbit. The largest of the pack – asteroid 2004 UE – is on track to make its closest approach to the planet November 13.

 

Asteroid 2004 UE is approximately 160 meters in diameter and will travel close to the Earth this week. Any object over 140 meters in diameter could cause major damage to cities or coasts if there were to be a collision, said astronomy professor Leslie Looney. “Asteroid 2004 UE is not considered a safety concern since the closest approach to Earth’s orbit on November 13 will be more than 30 times the Earth-moon distance.” Credit: Photo by L. Brian Stauffer

What are near Earth objects, what are they composed of and how do we know?

Near Earth objects are meteoroids, asteroids, or comets with orbits that bring them close to Earth’s orbit. They are the leftovers of our solar system formation process, which means they are the nearly pristine bits and pieces of ice and rocks from which the planets formed. We know their orbits from tracking them, and we know of their composition from examining their reflected and infrared light and by comparisons to objects that we have visited with space missions.

There seem to be a lot of large NEOs in Earths neighborhood in recent weeks. Is this unusual?

Over the last 20 years, NASA has dramatically increased the number of known NEOs – from knowing of less than a thousand to nearly 28,000. The precise dimensions of NEOs can be difficult to resolve due to their small size and great distances. However, those estimated by NASA to be 140 meters or more along their longest axis – most asteroids are potato-shaped, so their dimensions can be described as roughly spherical – have been mandated by Congress to be classified as NEOs. The increase in the number of objects classified as NEOs was in part due to this mandate. Anything of this size could have a catastrophic impact on Earth, destroying cities with large losses of life. This awareness leads to more reporting of objects.

Source: A Large Asteroid Will Pass by Earth This Week – Is It a Threat to the Planet?