2013 is set to be a year of asteroids and comets. On February 15, Earth will get a visit from "2012 DA14," a cosmic rock about 50 meters thick. Experts say a collision with Earth is unlikely. That, however, wasn't the case earlier Friday when a 10-ton meteor, independent of 2012 DA14, impacted central Russia, injuring several hundred people.
Asteroid specialists calcuate a 1 in 7.5 million chance 2012 DA14 could strike our planet. Objects in this size category - about 150 feet across - zip by Earth nearly as close about every 40 years.
This will be an astronomical year, literally. Several asteroids and comets are expected to pass the Earth in the coming months. But not every astronomical event is rare. For example, meteor showers are common and can be seen every year.
Comets are made up of a cloud of gas and a huge gas tail, stones and innumerable particles of dust. When pieces of the comet - even tiny ones - make it into the Earth's atmosphere they burn at temperatures of over 3,000 degrees C and light up to form a shooting star.
The Perseids are a prolific meteor shower, associated with the comet Swift-Tuttle. Every summer, the meteor shower crosses the Earth's orbit. The Perseids are named after the constellation they are closest to when they can be spotted. It is derived from Perseus, a character from Greek mythology.
Dust from meteors burns up completely in the atmosphere. Most meteorites that reach the Earth are harmless and no larger than a stone. Still, large meteorites can cause severe devastation. One of the largest meteorite craters is the Barringer Crater in Arizona with a diameter of 1,000 meters. It is 50,000 years old.
About 65 million years ago, a giant meteorite slammed into the Yucatan Peninsula (simulated in the image to the right). The result led to the creation of the Chicxulub Crater, which is more than 180 kilometers in diameter. Experts believe that the impact wiped out dinosaurs. Recent evidence shows that debris from a collision between two asteroids 160 million years ago led to the event.
Meteorites look like burnt rocks. The crust is formed when the meteorite melts upon entering the Earth's atmosphere. Other planets are also struck by meteorites. NASA's Opportunity Rover discovered the first extraterrestrial meteorites on Mars in 2005.
Meteors are the dust particles from a comet - a fragile, irregularly shaped celestial body that can stretch a few kilometers. Scientists believe they are the remnants from the formation of planets and their composition can provide information about the early solar system. Comets could also strike the Earth.
Almost all of meteorites that have been found on Earth come from asteroids - 99.8 percent of the more than 30,000. And just like comets, asteroids are created when a planet is being formed. They have no permanent atmosphere and little self-gravity.
Asteroids and comets are being observed by scientists. But the likelihood that the kilometer-sized objects with strike the Earth is small - one in a million years. Smaller bodies of tens of meters strike the Earth every 100 to 1,000 years. Meteorites of about one meter strike about once a year.
In the coming months, our skies are set for a lot of activity, with the year set out to be one of the most significant for astronomical activity. DW looks at some of the celestial bodies.