Can asteroids be hidden in Earth orbit?

Can the earth protect itself from asteroids?

Again and again, huge boulders fly relatively close to the earth. For example in April 2018, when an asteroid with a diameter of 50 meters came dangerously close to the earth. It came towards us from the dark depths of space and astronomers had only discovered it 21 hours before the flyby.

Five years earlier, a 20-meter meteorite hit the earth near Chelyabinsk in Russia. The catastrophe was still relatively mild: Thousands of buildings were damaged by the pressure wave. And more than a thousand people were injured, mostly from broken glass. But luckily there were no dead.

Astronomers are quite confident that they are familiar with the much more dangerous projectiles, which are about several kilometers in diameter, and that the earth is not threatened with any great danger for at least the next 100 years.

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Medium-sized floors are difficult to predict

But even "smaller" chunks with a diameter of only hundreds of meters can cause devastating damage to regions. The fall of the two asteroids also shows that we cannot know all of them.

For this reason, 300 astronomers, space engineers and other experts from the USA, Russia, China, Germany, France and Israel have been discussing the "space situation" since this week.

The International Planetary Defense Conference in Maryland, USA, is primarily about possible defense strategies. The US space agency NASA is organizing the conference together with researchers from the Johns Hopkins Applied Physics Laboratory (APL).

As a scenario, the scientists have devised a hypothetical asteroid up to 300 meters in size that rushes towards Earth at a speed of 14 kilometers per second, i.e. at around 50,000 kilometers per hour, from a distance of 57 million kilometers. The probability that he will hit us is therefore one percent. One way to deal with this would be to evacuate the threatened region on earth.

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Astronaut Alexander Gerst photographed this meteorite crater in Arizona from the ISS.

Evacuate or Distract?

At the conference, the participants will also demonstrate various methods of how mankind can divert the asteroid from its dangerous orbit, such as a double asteroid deflection test (DART) developed by NASA and developed by the NASA office for the coordination of the planetars Defense in Washington together with APL. In 2022, a real 150-meter-thick asteroid, which is not dangerous for the earth, is to be deflected from its orbit by a collision. The researchers want to find out whether such a method promises success.

DART is part of a national strategy and action plan to protect against near-earth objects in the USA. "Near Earth" are asteroids whose orbit around the sun is closer than 50 million kilometers to the earth's orbit. More than 20,000 of them are known and a good 700 are added every year.

"We have to make it clear to people that this is not about Hollywood," said Jim Bridenstine of NASA at the opening of the conference, reports AFP. His colleague Detlef Koschny from the European Space Agency ESA agreed: "The good thing about the Chelyabinsk disaster was that it made political decision-makers aware of the danger."

You only see those in the light - you cannot see those in the dark

The greatest uncertainty comes from objects in the vicinity of the sun, which are virtually invisible from Earth due to the light conditions. These can only be discovered - if at all - with special telescopes located in Arizona, Hawaii, Chile, Spain and Sicily.

Now astronomers are also discussing the construction of another space telescope for this purpose. It could be looking from a different perspective. Alternatively, you could set up a telescope on the far side of the moon. Because it was shielded from the earth, it would have a much better view of the depths of space.

  • Projectiles from space

    Guest from space

    The asteroid 2011 ES4 will presumably rush past us on September 1st at a safe distance of a good 120,000 kilometers - three times closer than the moon. We don't know exactly what the asteroid looks like. One thing is certain: with a diameter between 22 and 49 meters, it is one of the smaller asteroids.

  • Projectiles from space


    The asteroid 2020 QG, which paid us a short visit on August 16, 2020, was even smaller. Its diameter was only between three and six meters. On the other hand, it came pretty close: its distance at the closest point was only 2950 kilometers. It was so close to earth that its trajectory was deflected.

  • Projectiles from space

    Several kilometers thick

    But it can also be bigger: At the beginning of September 2017, Florence flew past the earth: a huge chunk with a diameter of 4.4 km. "Flying past" is relative, however - the distance was seven million kilometers. The asteroid was discovered in 1981 and is named after the British nurse Florence Nightingale, who lived from 1820 to 1910.

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    Just over

    In February 2013, a 130,000-ton asteroid named 2012 DA14 scraped past Earth. It came within 27,000 kilometers of our planet - closer than some satellites.

  • Projectiles from space

    Meteorites are not without danger

    Meteorites are asteroids and other celestial bodies that penetrate the earth's atmosphere and hit the ground. Then they can wreak havoc.

  • Projectiles from space

    Giant meteorite

    A gigantic meteorite hit the Yucatan peninsula about 65 million years ago. The Chicxulub crater created by it has a diameter of 300 kilometers ago. Experts believe that this impact wiped out the dinosaurs.

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    Black stones

    Meteorites are visually similar to the stones on earth, but look a bit burnt on the outside. This crust is created when the meteorite is melted when it enters the earth's atmosphere.

  • Projectiles from space

    Comets and falling stars

    Comets consist of a gas cloud and a huge tail made of gas, rocks and countless dust particles. If comet dust grains get into the earth's atmosphere, they get over 3000 degrees Celsius and begin to glow. A shooting star emerges.

  • Projectiles from space

    Falling stars

    If a comet flies particularly close to the earth, countless shooting stars fall on the earth. It is a tremendous spectacle every time it rains falling stars, like here over Stonehenge in England.

  • Projectiles from space

    Better safe than sorry

    In 2013, the European space agency ESA opened a coordination center for near-earth objects in Frascati, Italy. Data from telescopes like this one on Tenerife converge there.

    Author: Judith Hartl, Brigitte Osterath