OPENSPACE 24: The Future of Space Exploration | Page 32
Interview
Marco Micheli, Astronomer and NEO Observer
NEOS AND THE RISK OF COLLISION WITH EARTH
During the past few years, the discovery of
new near-earth objects (NEOs) has grown
significantly, with new and more powerful
telescopes finding many smaller objects of 10
meters or less hurtling through space. Those
objects are obviously not as threatening as
the km-sized ones that can cause global
A
s an astronomer and NEO observer, Marco
Micheli has been studying NEOs for over 20
years. He works at the ESA Space Situational
Awareness (SSA)-NEO Coordination Centre in Frascati,
Italy, where he observes those asteroids and comets
that are considered most dangerous to our planet. We
spoke with him about NEO research and the risk of
collision with Earth.
consequences if they impact our planet, but
they can still cause significant local damage if
they impact a populated area, which is what
occurred in Russia in 2013 when an asteroid
impact injured about 2000 people.
What are the odds of an NEO impact happening in
the near future?
Among the objects we know, the one with the highest impact
probability will come close to Earth in 2095. The risk of this
tiny object (10 m in diameter) colliding with Earth is around 10
percent. Even if it were to collide, it would likely disintegrate
in the atmosphere and not cause any damage.
Among the unknown objects, statistically, we can expect
that an object of about 50 m in diameter may hit Earth every
few centuries. Larger objects are rarer but can cause large
devastation, and it is important to discover them as far in
advance as possible.
What would be the effect of an NEO hitting the Earth?
The actual threat of a NEO hitting the Earth depends mostly on
its size. On the smaller end, objects a few meters in diameter
often just result in a bright meteor in the sky and sometimes
the fall of fragments on the ground.
Professor Richard Wainscoat (right) and Marco Micheli
(left), astronomer and NEO observer. Credit: University of
Hawaii Institute for Astronomy.
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Larger objects from 10 to 20 meters in diameter can cause
significant damage. An object of a few hundred meters in
diameter could create a major disaster on a regional scale,