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Looking at Earth from the asteroid Lutece. Image via J. Major / ESA
Via the Technical University of Munich
Sixty-five million years ago, a 15-kilometer asteroid erased two-thirds of life on Earth, including dinosaurs. But that 's probably not what kind of asteroid we should be worried about. These are the smaller NEOs that pose a more imminent threat, such as the asteroid that struck the Earth on June 2 and that scientists saw coming one day in advance.
Internationally renowned astronomers, astrophysicists and space scientists gathered in Garching near Munich. , Germany, from May 14 to June 8, 2018, for the development of new strategies to improve detection, scientific and commercial exploitation and defense against near-Earths.
Flyeye-telescope planned by the ESA as part of the overall effort to chase at-risk celestial objects such as asteroids and comets. Image by A. Baker / ESA
Detlef Koschny, Head of the Near Earth Objects team at the European Space Agency (ESA) and lecturer at the European Space Agency's astronautic chair. Munich Technical University explains why scientists are accentuating their research Let's start with a basic question: How is an asteroid different from a meteorite?
Detlef Koschny : Asteroids are objects of more than one meter – for example For example, the object that exploded on Botswana earlier this month. Meteorites are objects of less than one meter. When they enter and pbad through the atmosphere of a planet, they call meteorites. Comets are asteroids with large amounts of volatile compounds such as ice water. When they approach the sun, these compounds vaporize, creating their distinctive tails.
The disastrous films of Hollywood as Armageddon still include colossal asteroids on a trajectory of direct collision with the Earth. Detlef Koschny : NEOs that may approach or hit our planet range in size from a few millimeters to about 50 to 60 kilometers (30 to 37 miles) in diameter. We detected the majority of the largest NEOs and calculated their trajectories as well as the statistical risk of collision with Earth 100 years later.
We mapped 90% of asteroids of one kilometer or more. We know exactly where the big ones are and that they will not pose a threat. In the "average" region, the situation is completely different: we have only detected and mapped less than 1% of NEOs of less than one kilometer.
If a 100-meter (328-foot) asteroid struck the Earth, cause significant damage in an area the size of Germany, and even affect the surrounding area. But asteroids of this size do not hit Earth very often. Maybe every 10,000 years on average.
From 100 meters to 50 meters (164 feet), the statistical frequency of strikes increases at once every 1,000 years. Exactly one century ago, in 1908, a 40-meter object struck the Earth over Tunguska in Siberia, destroying a forest area the size of the Munich metropolitan area.
And if we descended to asteroids of about 20 meters feet – like the asteroid that exploded on Chelyabinsk in Russia in 2013, which ended up hurting 1500 people – these accidents occur on average every 10 to 100 years. We will certainly see something like this in our lifetime
No one has seen the Chelyabinsk asteroid arrive before it hits. And scientists have spotted only one who hit Botswana a few hours in advance. What is the current state of NEO detection technology?
Detlef Koschny : At the present time, there are two major Earth investigation programs, both funded by our American colleagues. They use optical telescopes that cover a wide field of view and can continuously scan the night sky to detect bright objects.
When it comes to detecting larger objects, this strategy works pretty well because they are visible they are still far from Earth. But detecting smaller objects up to a height of 20 meters (66 feet) is very difficult. They are not bright enough to be detected until they are at least as close as the moon.
If you only have two of these telescopes on the planet and that each telescope takes three weeks to cover the entire sky, you have to be really lucky that a small asteroid crosses your field of view just when you look in the right way.
That's why we are currently developing extremely large telescopes that will have the ability to scan the entire sky in just 48 hours. In addition, as part of ESA's Space Situational Awareness (ESA) program, we mobilize observatories and astronomers around the world via the NEO Coordination Center of the European Space Research Institute (ESRIN). ) of the Agency in Italy. Detlef Koschny, lecturer at the TUM Chair for Astronautics and head of the Near Earth Objects team at the European Space Agency (ESA). Image via A. Battenberg / TUM
So, what are your recommendations for improving detection and tracking capabilities, and what new sensing technologies are currently being deployed or in the near future?
Detlef Koschny: There is a system called the latest land-based hazard warning system (ATLAS) that has just come online in the United States. It consists of small telescopes that, even if they do not see very weak objects, cover most of the night. Here in Europe we are building the Flyeye telescope, with an effective opening of one meter. It provides us with a large field of vision that is more than 100 times the size of the full moon in the night sky. In one night, with a telescope, we can cover about half of the sky. The strategy to achieve this was developed by one of our masters students here at TUM
Our conclusion at the end of the conference and one of the recommendations we will make in the post-white paper conference: There is an urgent need for telescopes capable of sweeping the sky for these near-Earth objects, and a global network of telescopes working in concert, so that we can really cover the smallest range of asteroids in orbit near ground. We must absolutely FIND these objects before we can take concrete measures to defend ourselves against them.
Conclusion: An astrophysicist explains why it is the smaller objects near the Earth (NEO) that pose a more imminent threat. ] Voice of EarthSky "width =" 150 "height =" 150 "clbad =" photo "/>
