Later this month, NASA will launch the Double Asteroid Redirection Test (DART), a mission intended to test the second step of planetary defense redirecting a dangerous asteroid from Earth's course. With this mission, we might come up with questions: Are asteroids dangerous to Earth? Is this mission required?
Near-Earth Objects
According to NASA, asteroids and comets in the vicinity of Earth's orbital neighborhood, or within 120 million miles (195 million kilometers) of the Sun, are considered near-Earth objects. The majority of objects in the vicinity of Earth are asteroids, which can be anywhere between a few meters in height and roughly 25 miles (40 kilometers) in width.
Each object's orbit is calculated by selecting the elliptical path through space that best fits all of the currently available observations, which frequently cover a wide range of orbits over many years or decades. It becomes possible to estimate where an item will be years or even decades in the future, as well as whether it might approach Earth, as more observations are taken, greatly increasing the precision of an object's orbit.
Most near-Earth objects have orbits that don't bring them close to Earth, so there is no chance of impact. However, a tiny number of them, known as potentially hazardous asteroids, need special attention. Asteroids larger than 460 feet (140 meters) in size and with orbits within 4.6 million miles (7.5 million kilometers) of Earth's orbit around the Sun are considered to be these objects. CNEOS regularly monitors all known near-Earth objects to determine any potential impact danger.
Scientists have identified approximately 750,000 asteroids to date, but millions more space rocks are likely bouncing around the entire solar system.
Which asteroid has the highest chance of striking Earth?
According to Interesting Engineering, two asteroids that are frequently predicted to strike Earth in the next century are Bennu and 1950 DA.
In 1950, the asteroid 1950 DA was found. Its diameter is 1.1 kilometers or 0.68 miles. NASA estimates the likelihood of an impact in the year 2880 is one in 300. If it hits Earth, it will likely collide with the ocean, causing enormous tsunamis and flooding in coastal areas.
On the other hand, the diameter of the asteroid Bennu is 1,722 feet (525 meters). It could wreak planetary-scale havoc if it crashed with Earth, which NASA estimates may happen between 2175 and 2199. However, it's also thought that the likelihood of an impact is only one in 1,750.
ALSO READ: Asteroid, Comet Threat: What is NASA's Plan When Space Rocks Hit Earth?
NASA's Planetary Defense
According to Space.com, planetary defense has two essential phases. Later this month, NASA will launch the Double Asteroid Redirection Test (DART), a mission intended to test the second phase of planetary defense by preventing a dangerous asteroid from colliding with Earth.
But before anyone can even attempt to redirect an asteroid, researchers must locate the space rock and map out its trajectory over a long period to determine whether it will strike Earth.
According to Nancy Chabot, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Maryland and the coordination lead for DART, people might believe planetary defense is all about deflecting asteroids, but it's not. To take action against asteroids in the future, it is essential to keep track of them, identify them, and locate them.
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