Why we should thank ‘killer’ asteroids for all life on Earth

Scientists consider it a matter of when, not if, an asteroid large enough to wipe out human civilization is on a collision course with Earth. That’s why these same scientists are working on ways to blast or push these horrific, inevitable rocks.

But these efforts may be a bit ridiculous. While a giant space rock in the future could end life on Earth, it is possible… past The giant space rock helped Creates Life on Earth. This hypothetical formation rock is the subject of a new study by Nicholas Wogan, an astrobiologist at the University of Washington.

Asteroid or several Asteroids may have mixed Earth’s sterile, nitrogen-rich atmosphere, mixing the right elements into the right mixture to start a chemical chain reaction. This process continued for eons, eventually seeding the planet with the raw materials needed for life and, most importantly, a vital life-sowing compound called hydrogen cyanide.

“Massive impacts are one of the only mechanisms that allow Earth to have significant concentrations of hydrogen cyanide in surface environments,” Wogan and his colleagues wrote in their peer-reviewed study, which has been accepted for publication at the University of California. Planetary Science Journal.

The possibility of life starting on an asteroid solves a problem that has been vexing astrobiologists for decades. We have a good understanding of what Earth’s atmosphere was like when the planet was young, billions of years ago. We also know what kind of atmosphere housed those first snippets of RNA that eventually evolved into bacteria, dandelions, fish, elephants, and, of course, humans.

What we don’t know for sure is why Earth traded one sterile atmosphere for another to the benefit of biology. Something is needed to boil the oceans, inject water and hydrogen into the air and add a healthy dose of methane so that these chemicals can combine to form cyanide, which has a “very rich chemistry,” according to Nobel Prize-winning Harvard biologist Jack Szostak. It is probably the main component of ribonucleic acid (RNA), and thus life.

In general, scientists agree that there are two main possibilities: volcanoes and asteroids. But chemical analysis of very old rocks suggests that early volcanoes produced a lot of nitrogen and carbon dioxide, but not much methane, Wogan and his colleagues said. Something else is needed to inject the evolutionarily necessary methane into the air.

This something else might have been one or a few well-timed massive asteroids. An iron-rich rock, 300 miles across, would have been blasted to Earth’s surface with the force of millions of atomic bombs, spewing unfathomable amounts of debris, or “projectiles.”

“Iron-rich projectiles could interact with an ocean that evaporates as a result of the impact,” the study authors explained.

The atmosphere that was previously rich in nitrogen will transform into one rich in hot water and hydrogen with healthy streaks of carbon. As the air cooled over thousands of years, methane rained down on the newly forming oceans. “Such a reduced atmosphere would have generated prebiotic molecules” such as hydrogen cyanide, the study authors wrote. Prebiotic molecules are exactly what they sound like: molecules that come right before biology in the evolutionary process.

The Genesis rocks are an elegant solution to the mystery of life’s origins, but that doesn’t mean they’re an indisputable fact. Yes, the impact of one or more giant asteroids may explain the methane rain that produced cyanide-flavored oceans that eventually filled with single-celled organisms. But what if we’re wrong, and early evolution didn’t depend much on cyanide? In this case, we don’t need asteroid impacts to explain how life emerged.

“A better understanding of the organic chemistry that led to the origin of life would be beneficial,” Wogan told The Daily Beast.

Currently, asteroid-assisted cyanide-based chemistry is a leading theory to explain how a lifeless planet became a living planet. It highlights one of the great paradoxes of evolution: the same forces that may have created life could also have destroyed it, and may do so in the future.

In their study, the authors stress “how ‘lucky’ primitive life would have been if it was created by post-collision particles, taking into account the need not to be subsequently annihilated by further collisions.” One or a few large space rocks hit the Earth in succession and stirred up the air and oceans enough. But another large rock, striking just after the first organisms began circling the shallow tidal pools, would have wiped out those same organisms. Evolution and global extinction, in close succession.

How lucky are we to be here, considering how often giant asteroids seem to hit our planet? “That’s a very difficult question to answer,” Wogan said. “Some of the problems are that we don’t know the Earth’s impact history well about four billion years ago, and it’s hard to know whether or not a big impact would really sterilize the entire planet.”

Jonathan Itkowitz, a Cambridge astronomer, told The Daily Beast he was optimistic. “Even if the necessary conditions (for evolution) are only present at one in a million sites, and if only one in a million sites survives significant subsequent impacts, there is still a chance that the chemistry will persist and flourish.”

In other words, life can find a way.

Wogan admitted that it was possible that one asteroid began evolution only to be interrupted by another – but then… third The asteroid came and started the process all over again, and so on until life finally spread so far and wide that it became more difficult to eradicate.

None of this means we should take any chances, of course. Just because our single-celled ancestors might have survived some truly horrific asteroid impacts doesn’t mean that we, as a technological civilization consisting mostly of meat and water, would also survive a direct hit from a giant space rock. We can be grateful that a large asteroid impact may have driven our evolution while also doing everything possible to prevent it from happening. the next Large asteroid impact.

(Tags for translation)Science

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