Nav: Home

Gigantic asteroid collision boosted biodiversity on Earth

September 18, 2019

An international study led by researchers from Lund University in Sweden has found that a collision in the asteroid belt 470 million years ago created drastic changes to life on Earth. The breakup of a major asteroid filled the entire inner solar system with enormous amounts of dust leading to a unique ice age and, subsequently, to higher levels of biodiversity. The unexpected discovery could be relevant for tackling global warming if we fail to reduce carbon dioxide emissions.

In the last few decades, researchers have begun to understand that evolution of life on Earth also depends on astronomical events. One example of this is when the dinosaurs were wiped out instantaneously by the Cretaceous-Paleogene impact of a 10 km asteroid.

For the first time, scientists can now present another example of how an extraterrestrial event formed life on Earth. 470 million years ago, a 150 km asteroid between Jupiter and Mars was crushed, and the dust spread through the solar system.

The blocking effect of the dust partially stopped sunlight reaching Earth and an ice age began. The climate changed from being more or less homogeneous to becoming divided into climate zones - from Arctic conditions at the poles, to tropical conditions at the equator.

The high diversity among invertebrates came as an adaptation to the new climate, triggered by the exploded asteroid.

"It is analogous to standing the middle of your living room and smashing a vacuum cleaner bag, only at a much larger scale", explains Birger Schmitz, professor of geology at Lund University and the leader of the study.

An important method that led to the discovery was the measurements of extraterrestrial helium incorporated in the petrified sea floor sediments at Kinnekulle in southern Sweden. On its way to Earth, the dust was enriched with helium when bombarded by the solar wind.

"This result was completely unexpected. We have during the last 25 years leaned against very different hypotheses in terms of what happened. It wasn't until we got the last helium measurements that everything fell into place" says Birger Schmitz.

Global warming continues as a consequence of carbon dioxide emissions and the temperature rise is greatest at high latitudes. According to the Intergovernmental Panel on Climate Change, we are approaching a situation that is reminiscent of the conditions that prevailed prior to the asteroid collision 470 million years ago.

The last decade or so, researchers have discussed different artificial methods to cool the Earth in case of a major climate catastrophe. Modelers have shown that it would be possible to place asteroids, much like satellites, in orbits around Earth in such a way that they continuously liberate fine dust and hence partly block the warming sunlight.

"Our results show for the first time that such dust at times has cooled Earth dramatically. Our studies can give a more detailed, empirical based understanding of how this works, and this in turn can be used to evaluate if model simulations are realistic", concludes Birger Schmitz.
-end-
In addition to Lund University, the following Universities and organizations have been involved in the study: California Institute of Technology, Vrije Universiteit Brussel, The Field Museum of Natural History, University of Chicago, The Ohio State University, Université Libre de Bruxelles, Russian Academy of Sciences, Federal University Kazan, Royal Belgian Institute of Natural Sciences, Durham University, Chinese Academy of Sciences, Center for Excellence in Comparative Planetology China, ETH Zürich, Naturmuseum St. Gallen Switzerland, Woods Hole Oceanographic Institution.

Lund University

Related Solar System Articles:

Pressure runs high at edge of solar system
Out at the boundary of our solar system, pressure runs high.
What a dying star's ashes tell us about the birth of our solar system
A UA-led team of researchers discovered a dust grain forged in a stellar explosion before our solar system was born.
What scientists found after sifting through dust in the solar system
Two recent studies report discoveries of dust rings in the inner solar system: a dust ring at Mercury's orbit, and a group of never-before-detected asteroids co-orbiting with Venus, supplying the dust in Venus' orbit.
Discovered: The most-distant solar system object ever observed
A team of astronomers has discovered the most-distant body ever observed in our solar system.
Discovery of the first body in the Solar System with an extrasolar origin
Asteroid 2015 BZ509 is the very first object in the Solar System shown to have an extrasolar origin.
First interstellar immigrant discovered in the solar system
A new study has discovered the first known permanent immigrant to our solar system.
A star disturbed the comets of the solar system in prehistory
About 70,000 years ago, when the human species was already on Earth, a small reddish star approached our solar system and gravitationally disturbed comets and asteroids.
Scientists detect comets outside our solar system
Scientists from MIT and other institutions, working closely with amateur astronomers, have spotted the dusty tails of six exocomets -- comets outside our solar system -- orbiting a faint star 800 light years from Earth.
Does the organic material of comets predate our solar system?
The Rosetta space probe discovered a large amount of organic material in the nucleus of comet 'Chury.' In an article published by MNRAS on Aug.
Tracking a solar eruption through the solar system
Ten spacecraft, from ESA's Venus Express to NASA's Voyager-2, felt the effect of a solar eruption as it washed through the solar system while three other satellites watched, providing a unique perspective on this space weather event.
More Solar System News and Solar System Current Events

Top Science Podcasts

We have hand picked the top science podcasts of 2019.
Now Playing: TED Radio Hour

Risk
Why do we revere risk-takers, even when their actions terrify us? Why are some better at taking risks than others? This hour, TED speakers explore the alluring, dangerous, and calculated sides of risk. Guests include professional rock climber Alex Honnold, economist Mariana Mazzucato, psychology researcher Kashfia Rahman, structural engineer and bridge designer Ian Firth, and risk intelligence expert Dylan Evans.
Now Playing: Science for the People

#541 Wayfinding
These days when we want to know where we are or how to get where we want to go, most of us will pull out a smart phone with a built-in GPS and map app. Some of us old timers might still use an old school paper map from time to time. But we didn't always used to lean so heavily on maps and technology, and in some remote places of the world some people still navigate and wayfind their way without the aid of these tools... and in some cases do better without them. This week, host Rachelle Saunders...
Now Playing: Radiolab

Dolly Parton's America: Neon Moss
Today on Radiolab, we're bringing you the fourth episode of Jad's special series, Dolly Parton's America. In this episode, Jad goes back up the mountain to visit Dolly's actual Tennessee mountain home, where she tells stories about her first trips out of the holler. Back on the mountaintop, standing under the rain by the Little Pigeon River, the trip triggers memories of Jad's first visit to his father's childhood home, and opens the gateway to dizzying stories of music and migration. Support Radiolab today at Radiolab.org/donate.