An asteroid is going to pass by Earth for Christmas. However, it has no shining tail like the star of Bethlehem. And it may be difficult to spot - even for hobby astronomers, because the asteroid won't get that close.
The New Year's Eve asteroid won't come nearly as close as 2012 DA14 did in November 2013Image: NASA/Science dpa
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Threat from above
About 10,000 asteroids loom close to Earth. This year has already witnessed a lot of astronomical activity. And Europe is building what could become an asteroid early warning system.
Image: AP
European early warning system
About 10,000 asteroids loom close to Earth. They could be dangerous. The European Space Agency (ESA) is building an early warning system in Frascati, Italy. Data from telescopes like this one on Tenerife will be collated there.
Image: IQOQI Vienna
Passing blast
If you're wondering how important early warning systems are, think of the meteorite that struck Earth near Chelyabinsk in Russia on 15 February 2013. The blast was estimated to have been as strong as between 100 and 1000 kilotons of TNT explosives. Almost 1500 people were injured.
Image: picture-alliance/dpah
A big splash
Before it had burned up in the Earth's atmosphere, the meteorite is estimated to have had a diameter of 20 meters. All that was left was a piece weighing only about a kilogram. But it still managed to smash a six meter wide hole in the ice.
Image: Reuters
Bigger and badder
But an asteroid named "2012 DA14" was much more dangerous. It weighed 130,000 tons. On the same day as the Chelyabinsk strike, 2012 DA14 flew passed our planet at a distance of just 27,000 kilometers. That is closer than some satellites.
Image: NASA/Science dpa
Whizz by Earth
A number of other asteroids and comets are expected to come close to Earth this year. Scientists are keeping a close eye on them because even the smallest rocks can be dangerous.
Image: picture-alliance/dpa
Comets and shooting stars
Comets consist of a cloud of gas and a huge tail of gas, stones and particles of dust. When the tiny grains of dust from a comet scrape the Earth's atmosphere, they can get as hot as 3,000 degrees Celsius. They start to glow and become a shooting star.
Image: picture alliance / dpa
The most famous meteor shower
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 seen. It is derived from Perseus, a character from Greek mythology.
Image: AP
When meteoroids don't burn up
Meteors dust burns up in our atmosphere. Most meteorites (meteoroids that survive falling through the atmosphere) are harmless and are often no bigger than a stone. But large meteorites can cause a lot of damage. One of the largest meteorite craters is the Barringer Crater in Arizona. It has a diameter of 1,000 meters and is 50,000 years old.
Image: cc-by/LarryBloom
End of an era
About 65 million years ago, a giant meteorite slammed into the Yucatan Peninsula (simulated in the image to the right). It led to the creation of the Chicxulub Crater, which is more than 180 kilometers in diameter. Experts believe the impact wiped out the dinosaurs. More recent evidence suggests that debris from a collision between two asteroids 160 million years ago led to the event.
Image: picture alliance/dpa
Burnt rocks from outer space
Meteorites look like burnt rocks. Their 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.
Image: picture-alliance/ dpa/dpaweb
Dust and gas
It's not just the dust from comets that reaches Earth - but the comets do, too. Experts believe comets to be bits leftover from the creation of planets. They may also hold secrets about the beginnings of our solar system.
Image: AP
Large chunks of rock
Almost all of meteorites found on Earth have come from asteroids - that is 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 hardly any gravity.
Image: picture-alliance/ dpa
And after all that...
... the chance of a large asteroid hitting Earth in the next 100 years is (said to be) quite small.
Image: AP
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The asteroid with the number 163899, also known under the name 2003 SD220, will fly by planet Earth at a safe distance of 11 million kilometers on New Year's Eve. That's equivalent to 28 times the distance between us and the moon.
As a comparison: The last asteroid that flew by Earth on a holiday came much closer to our planet. "The great pumpkin," also known as "2015 TB145," came as close as only 500,000 kilometers to our planet right on Halloween this year.
And in 2013 the asteroid 2012 DA14 flew by Earth as close as 28,000 kilometers. That's lower than some geostationary communication satellites are orbiting the Earth.
No unusual asteroid
The New Year's Eve asteroid falls into a class of celestial objects that are not uncommon. There are several per year, and they are not considered a threat to us. Only asteroids that approach Earth closer than 300,000 kilometers deserve special attention from astronomers.
2003 SD220 has an estimated diameter of about 700 meters. Objects of such size would cause global damage if they struck Earth. However, astronomers estimate that such an impact would happen only once in about 100,000 years.
Space engineers want to divert dangerous asteroids using spacecraftImage: ESA–Science Office
Keeping an eye on objects in space
Astronomers from the world's large space agencies are constantly keeping an eye on such threats from space. For the next 100 years, they exclude the possibility of such a severe meteorite hitting out planet.
The largest asteroids in our solar system are known to us, and their orbits have been calculated for decades to come. More problematic are smaller objects, even just over ten meters in size, as those can race towards earth undetected. Suddenly they can come out of the darkness and strike the Earth, like the 40-meter large rock that landed near the Siberian town of Chelyabinsk in 2013. The shockwave that ensued ultimately destroyed windows all over the town - and injured as many as 1,500 people.
The next spectacular fly-by of a big asteroid is expected in April 2029. That's when Apophis will pass Earth at a distance of only 30,000 Kilometers. That is roughly one tenth of the distance of the moon. Apophis is several hundred meters in diameter, and the asteroid is set to return once again after that - in 2036.
