Millions of space rocks fill the solar system. This week, three massive ones are set to fly by earth, according to NASA's Jet Propulsion Laboratory. The good thing is that the most proximate one will miss earth and maintain a distance of around 2.2 million miles. This is around 10 times the typical earth-moon distance.

Trio of Asteroids Set To Fly by Earth

Live Science reports that on February 27, asteroid 2012 DK31 will fly by earth at a distance of around 3 million miles. Its projected width is around 450 feet, making it as wide as the height of a skyscraper with 40 stories. This asteroid's solar orbit crosses with that of earth's every couple of years.

Though this asteroid does not bring any imminent dangers to earth, it has allegedly been classified by NASA as a PHA (Potentially Hazardous Asteroid). This classification is based on its huge size and on the fact that it is orbiting close to earth and may lead to damage if there are changes in its trajectory or if a collision takes place.

In general, asteroids that have a width of over 450 feet and that orbit within a distance of 4.6 million miles from earth are classified as PHAs. Nevertheless, Live Science reports that NASA has mapped out 200 years' worth of the asteroid's trajectory and that there are no projected collisions.

Yet another PHA, with the size of a skyscraper, is set to pass over earth on February 28. The asteroid also has a rough width of 450 feet, and it will be around 2.2 million miles away. Dubbed 2006 BE55, this PHA crosses the earth's orbit once every four to five years.

The third asteroid of the trio is set to move past earth on March 3. This rock, dubbed 2021 QW, is around 250 feet wide and will move at a distance of around 3.3 million miles. 2021 QW is not big enough to be categorized as a PHA. Nevertheless, it still approaches earth closely every couple of years.

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Why Do Scientists Monitor Asteroids?

Scientists have to closely monitor such space rocks because even minimal changes in their trajectory may lead them to draw into a collision course with earth. The good news is that, based on NASA's calculations, there are no known asteroids that are on a collision course with earth for at least a hundred years.

In case an asteroid directly poses any risks to earth, asteroids are already working on planetary defense measures. According to NASA, planetary defense generally covers the capacities necessary for picking up possibilities and for warning others of potential comet or asteroid impacts with earth. The field also covers the prevention of these impacts and the mitigation of their effects.

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