Asteroid impact would drastically change the world in ways we didn't even expect, scientists say
A medium-sized asteroid could bring dramatic changes to the Earth – in unexpected ways, according to a new simulation.
A new simulation looked at what would happen if the Earth collided with an asteroid with a diameter of around 500 metres, roughly the same as Bennu, a real rock that has been studied in great detail. There is a roughly 1-in-2700 chance of such a collision in 2182, and the Earth is hit by similar-sized asteroids about every 100-200 thousand years.
Researchers in the new study simulated what would happen to the climate if such a collision happened, and how the potentially 400 million tons of dust that would be released would change the world.
They found that it would have dramatic effects for ecosystems on Earth, in ways that could lead to food scarcity and other issues. But it also suggests there could be unexpected bright spots.
In the three or four years after the impact, in the most intense scenario, the sun would be dimmed and cool the surface by up to four degrees, reducing rainfall by 15 per cent and deplete the ozone by around 32 per cent. But those are just averages, and particular areas may be dramatically worse.
'The abrupt impact winter would provide unfavorable climate conditions for plants to grow, leading to an initial 20–30% reduction of photosynthesis in terrestrial and marine ecosystems. This would likely cause massive disruptions in global food security,' said Lan Dai, lead author on the study, in a statement.
But the oceans may be more hardy, they found – and might actually thrive. Plankton recovered within just six months, and then their numbers increased so that the population was even higher than when the asteroid hit.
That was the result of iron concentration on the dust, which would then drop into the oceans. That would provide more food for algae which would bloom and then attract large amounts of the small predators that feed on that algae.
'The simulated excessive phytoplankton and zooplankton blooms might be a blessing for the biosphere and may help alleviate emerging food insecurity related to the longer-lasting reduction in terrestrial productivity,' said Dr Lai.
'On average, medium-sized asteroids collide with Earth about every 100–200 thousand years. This means that our early human ancestors may have experienced some of these planet-shifting events before with potential impacts on human evolution and even our own genetic makeup,' said Axel Timmermann, co-author of the study.
Try Our AI Features
Explore what Daily8 AI can do for you:
Comments
No comments yet...
Related Articles
The Guardian
20-04-2025
- The Guardian
‘It blew us away': how an asteroid may have delivered the vital ingredients for life on Earth
Several billion years ago, at the dawn of the solar system, a wet, salty world circled our sun. Then it collided, catastrophically, with another object and shattered into pieces. One of these lumps became the asteroid Bennu whose minerals, recently returned to Earth by the US robot space probe OSIRIS-REx, have now been found to contain rich levels of complex chemicals that are critical for the existence of life. 'There were things in the Bennu samples that completely blew us away,' said Prof Sara Russell, cosmic mineralogist at the Natural History Museum in London, and a lead author of a major study in Nature of the Bennu minerals. 'The diversity of the molecules and minerals preserved are unlike any extraterrestrial samples studied before.' Results from this and other missions will form a central display at a Natural History Museum's exhibition, Space: Could Life Exist Beyond Earth?, which opens on 16 May. It will be a key chance for the public to learn about recent developments in the hunt for life on other worlds, said Russell. As the exhibition will reveal, the basic chemical building blocks for life can be found in other objects in the solar system such as meteorites. However, the material from Bennu, which is named after an ancient Egyptian mythological bird, have been found to be particularly rich in these deposits. 'Its parent world clearly had underground lakes of brine, and when these evaporated they left behind salts that resemble those found in dry lake beds on Earth,' said Russell. In addition, phosphates, ammonia and more than a dozen protein-building amino acids that are present in life forms on Earth – as well as the five nucleobase building blocks that make up RNA and DNA – were found in the samples brought back by OSIRIS-REx. 'These strongly suggest that asteroids similar to Bennu crashed on to Earth, bringing crucial ingredients that led to the appearance of life here,' she added. Scientists do not believe life evolved on Bennu itself but do think other asteroids like it might have supplied other worlds with the basic ingredients for life. On Earth, with its warm, stable environment, this led to the first appearance of reproducing organisms more than 3.7 billion years ago. It remains to be seen if they appeared on other promising worlds such as Mars and the moons of Jupiter and Saturn, that include Europa, Ganymede, Titan and Enceladus. These are now the subject of a number of missions that will feature in the exhibition and include two probes now heading for Jupiter's ice-covered moons Europa and Ganymede, which are known to possess liquid water oceans. In addition, the UK-built Rosalind Franklin robot rover is scheduled to land on Mars in 2029 and will drill deep into its soil, seeking evidence of life. In the past, samples of extraterrestrial rocks made available for study have been limited mainly to meteorites, pieces of the moon brought back by astronauts and robot probes, and lumps of Mars that were blasted towards Earth when large objects struck the red planet and blew debris into space – with some eventually falling on to our world as Martian meteorites. Visitors to the exhibition will be able to touch samples of lunar and Martian material as well as a meteorite that landed on our planet after breaking off from an asteroid. Intriguingly, this rock is older than the Earth itself. 'This is going to be a blockbuster,' said Sinead Marron, the museum's senior exhibitions manager. OSIRIS-REx brought back 120gm of Bennu dust to Earth, and the museum has been given around 200mg to study, said Russell. 'When we first opened the capsule, we saw this black dust everywhere, with white particles in it. We thought it might be contaminated. But it turned out to be a compound of phosphorus we have not seen in meteorites but which is absolutely crucial to the development of life. I was astonished.' The prospects that life might exist elsewhere in the universe made headlines last week when it was announced that observations of the exoplanet K2-18b by the James Webb space telescope had revealed the chemical fingerprints of two compounds that, on Earth, are only known to be produced by life. On their own, the chemicals, dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), do not amount to proof of alien biological activity but they have boosted hopes that we are not alone in the universe. Conclusively proving that life exists on distant worlds outside our solar system will be extremely hard, scientists acknowledge – short of a signal from an extraterrestrial intelligence announcing its existence. By contrast, alien lifeforms within our solar system will be easier to collect and study and may prove, one day, that life on other worlds does indeed exist. 'What we would do about such a discovery is a different matter,' Marron said. 'One of the things we will be asking exhibition visitors to think about is how we would treat life if we found it on Mars or another world. Would we stay away from it or try to interact with it? 'Or would we try to eat it, like we eat lifeforms with whom we share this planet? Such questions about alien life help us reflect on the ways we engage with other forms of life in our own world.'
Reuters
28-02-2025
- Reuters
Astronomers see lower risk of newly found asteroid hitting Earth
WASHINGTON, Feb 27 (Reuters) - New observations of a small asteroid discovered in December have led astronomers to conclude that the chances of it striking Earth are almost zero after earlier data had indicated a higher risk of a collision with this space rock about 130-300 feet (40-90 meters) wide. The asteroid, called 2024 YR4, is orbiting on a path that will bring it close to Earth in 2032, with scientists previously calculating impact probability at around 3%, the highest value ever recorded for such an object. The new data, obtained by the European Southern Observatory's Chile-based Very Large Telescope and other facilities, gave a more precise picture of the asteroid's future trajectory. The impact probability has been lowered to 0.001%, according to the European Space Agency's Near-Earth Objects Coordination Centre, while NASA's Jet Propulsion Laboratory put it at 0.004%. "The risk is plummeting," said Olivier Hainaut, an astronomer with the European Southern Observatory in Germany. NASA put the probability of the asteroid striking the moon at 1.7%. The asteroid has been closely monitored since its discovery because of the potential threat it poses. An impact potentially could cause regional devastation and significant loss of life. "An object 10 meters (33 feet) across would create an impact with the same energy as the Hiroshima bomb," said Hainaut, who estimated that an impact by YR4 would be 500 times more energetic than that. "Fortunately, it is very likely that most of that energy would be dumped in the high atmosphere when the asteroid comes in. Still, it is a pretty big blast, that could damage a city-wide area," Hainaut added. Asteroids have struck Earth occasionally over its long history, often with cataclysmic results. For example, an asteroid estimated at 6-9 miles (10-15 km) wide - much larger than 2024 YR4 - hit off the coast of Mexico's Yucatan Peninsula 66 million years ago, eradicating about three-quarters of the world's species and ending the age of dinosaurs. NASA in 2022 carried out a proof-of-principle planetary defense mission by using its robotic DART spacecraft to change the trajectory of the asteroid Dimorphos, with an eye toward doing this in the future if one appears on a collision course with Earth. Astronomers are learning more and more about asteroids. For instance, NASA's robotic OSIRIS-REx spacecraft journeyed to an asteroid named Bennu and in 2020 collected samples of rock and dust that, according to a study published in January, bore some of the chemical building blocks of life. Another study estimated the potential damage that would be caused if an asteroid the size of Bennu - with a diameter of roughly three-tenths of a mile (500 meters) - strikes Earth. Scientists have estimated a one-in-2,700 chance of a Bennu collision with Earth in 2182. Aside from the immediate devastation, the researchers estimated that an impact by a Bennu-sized asteroid would inject 100-400 million tons of dust into the atmosphere, causing disruptions in climate, atmospheric chemistry and global photosynthesis lasting three to four years.
The Independent
06-02-2025
- The Independent
Asteroid impact would drastically change the world in ways we didn't even expect, scientists say
A medium-sized asteroid could bring dramatic changes to the Earth – in unexpected ways, according to a new simulation. A new simulation looked at what would happen if the Earth collided with an asteroid with a diameter of around 500 metres, roughly the same as Bennu, a real rock that has been studied in great detail. There is a roughly 1-in-2700 chance of such a collision in 2182, and the Earth is hit by similar-sized asteroids about every 100-200 thousand years. Researchers in the new study simulated what would happen to the climate if such a collision happened, and how the potentially 400 million tons of dust that would be released would change the world. They found that it would have dramatic effects for ecosystems on Earth, in ways that could lead to food scarcity and other issues. But it also suggests there could be unexpected bright spots. In the three or four years after the impact, in the most intense scenario, the sun would be dimmed and cool the surface by up to four degrees, reducing rainfall by 15 per cent and deplete the ozone by around 32 per cent. But those are just averages, and particular areas may be dramatically worse. 'The abrupt impact winter would provide unfavorable climate conditions for plants to grow, leading to an initial 20–30% reduction of photosynthesis in terrestrial and marine ecosystems. This would likely cause massive disruptions in global food security,' said Lan Dai, lead author on the study, in a statement. But the oceans may be more hardy, they found – and might actually thrive. Plankton recovered within just six months, and then their numbers increased so that the population was even higher than when the asteroid hit. That was the result of iron concentration on the dust, which would then drop into the oceans. That would provide more food for algae which would bloom and then attract large amounts of the small predators that feed on that algae. 'The simulated excessive phytoplankton and zooplankton blooms might be a blessing for the biosphere and may help alleviate emerging food insecurity related to the longer-lasting reduction in terrestrial productivity,' said Dr Lai. 'On average, medium-sized asteroids collide with Earth about every 100–200 thousand years. This means that our early human ancestors may have experienced some of these planet-shifting events before with potential impacts on human evolution and even our own genetic makeup,' said Axel Timmermann, co-author of the study.
