41,000 Years Ago Earth’s Shield Went Down

An illustration of Earth's magnetic field. Image Credit: ESA/ATG medialab

Earth is naked without its protective barrier. The planet’s magnetic shield surrounds Earth and shelters it from the natural onslaught of cosmic rays. But sometimes, the shield weakens and wavers, allowing cosmic rays to strike the atmosphere, creating a shower of particles that scientists think could wreak havoc on the biosphere.

This has happened many times in our planet’s history, including 41,000 years ago in an event called the Laschamps excursion.

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Does the Rise of AI Explain the Great Silence in the Universe?

Will AI become indispensable in an age of "big data" astronomy? Credit: DALL-E

Artificial Intelligence is making its presence felt in thousands of different ways. It helps scientists make sense of vast troves of data; it helps detect financial fraud; it drives our cars; it feeds us music suggestions; its chatbots drive us crazy. And it’s only getting started.

Are we capable of understanding how quickly AI will continue to develop? And if the answer is no, does that constitute the Great Filter?

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DART Showed We Can Move an Asteroid. Can We Do It More Efficiently?

This illustration depicts NASA’s Double Asteroid Redirection Test (DART) spacecraft prior to impact at the Didymos binary asteroid system. Credit: NASA/Johns Hopkins APL/Steve Gribben
This illustration depicts NASA’s Double Asteroid Redirection Test (DART) spacecraft prior to impact at the Didymos binary asteroid system. Credit: NASA/Johns Hopkins APL/Steve Gribben

Like many of you, I loved Deep Impact and Armageddon. Great films, loads of action and of course, an asteroid on collision course with Earth. What more is there to love!  Both movies touched upon the options for humanity to try and avoid such a collision but the reality is a little less Hollywood. One of the most common options is to try some sort of single impact style event as was demonstrated by the DART (Double Asteroid Redirection Test) mission but a new paper offer an intriguing and perhaps more efficient alternative.

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Did a Comet Wipe out the Dinosaurs?

Artist's rendering of a comet headed towards Earth. Public domain illustration.

About 66 million years ago a massive chunk of rock slammed into Earth in what is the modern-day Yucatan Peninsula. The impact extinguished about 75% of all life on Earth. Most famously, it was the event that wiped out the dinosaurs.

While mainstream scientific thought has pointed to an asteroid as the impactor, a new research letter says it could’ve, in fact, been a comet.

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Scientists Think They Know What Caused the Deadliest Mass Extinction in the History of the Earth

This illustration shows the percentage of marine animals that went extinct during Earth's worst extinction at the end of the Permian era by latitude, from the model (black line) and from the fossil record (blue dots).A greater percentage of marine animals survived in the tropics than at the poles. The color of the water shows the temperature change, with red being most severe warming and yellow less warming. At the top is the supercontinent Pangaea, with massive volcanic eruptions emitting carbon dioxide. The images below the line represent some of the 96 percent of marine species that died during the event. [Includes fossil drawings by Ernst Haeckel/Wikimedia; Blue crab photo by Wendy Kaveney/Flickr; Atlantic cod photo by Hans-Petter Fjeld/Wikimedia; Chambered nautilus photo by John White/CalPhotos.]Justin Penn and Curtis Deutsch/University of Washington
This illustration shows the percentage of marine animals that went extinct during Earth's worst extinction at the end of the Permian era by latitude, from the model (black line) and from the fossil record (blue dots).A greater percentage of marine animals survived in the tropics than at the poles. The color of the water shows the temperature change, with red being most severe warming and yellow less warming. At the top is the supercontinent Pangaea, with massive volcanic eruptions emitting carbon dioxide. The images below the line represent some of the 96 percent of marine species that died during the event. [Includes fossil drawings by Ernst Haeckel/Wikimedia; Blue crab photo by Wendy Kaveney/Flickr; Atlantic cod photo by Hans-Petter Fjeld/Wikimedia; Chambered nautilus photo by John White/CalPhotos.]Justin Penn and Curtis Deutsch/University of Washington

Humanity can have a love/hate relationship with itself, but there’s no denying that we’re the pinnacle of evolution on Earth as things stand now. But it took an awfully long time for evolution to produce beings such as we. Several times, life had to drag itself back from near annihilation.

The largest extinction setback was the Permian-Triassic extinction, also called the “Great Dying,” some 252 million years ago. Up to 96% of all marine species and 70% of terrestrial vertebrate species went extinct.

What happened?

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A Supernova Exploded Dangerously Close to Earth 2.5 Million Years Ago

Visible, infrared, and X-ray light image of Kepler's supernova remnant (SN 1604) located about 13,000 light-years away. Credit: NASA, ESA, R. Sankrit and W. Blair (Johns Hopkins University).

In its 4.5 billion year history, Earth has had to run the gauntlet. Numerous catastrophes have imperilled the planet, from massive impacts, to volcanic conflagrations, to frigid episodes of snowball Earth. Yet life persists.

Among all of the hazards that threaten a planet, the most potentially calamitous might be a nearby star exploding as a supernova.

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A New Mass Extinction has been Discovered, Wiping Out Life 233 Million Years Ago, and Leading to the Rise of the Dinosaurs

Earth Observation has come a long way. But if satellites could orbit closer to Earth, in VLEO, then our observations would be a lot better. Image Credit: NASA Earth Observatory.

Most everybody knows that the dinosaurs perished rapidly in a tumultuous extinction, caused by an asteroid strike about 66 million years ago. But it looks like another extinction prior to the appearance of the dinosaurs paved the way for their long reign. That extinction took place about 233 million years ago.

And scientists have only now discovered it.

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Did Snowball Earth Happen Because of a Sudden Drop in Sunlight?

This artist's illustration shows what an icy exo-Earth might look like. A new study says liquid water could persist under ice sheets on planets outside of their habitable zones. Image Credit: NASA

Hundreds of millions of years ago, Earth went through two episodes of severe glaciation. These two episodes—the Sturtian and the Marinoan glaciations—occured during the Earth’s Cryogenian Period. The Cryogenian lasted from about 720 million to 635 million years ago.

The phenomenon is called “Snowball Earth” and both instances of it happened in pretty quick succession. And while a planet encased in ice and snow sounds devastating, these episodes may have paved the way for the development of complex life.

The question is, what caused the Earth to freeze over like that?

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It Was Almost Certainly an Asteroid Impact that Wiped Out the Dinosaurs. In Fact, Volcanoes Might Have Helped Life Recover

An ankylosaurus enjoying a drink of water while the asteroid strikes in the distance. Image Credit: Fabio Manucci

It seems almost certain that an asteroid impact wiped out the dinosaurs. But only almost. Another competing theory won’t completely go away: the extinction-by-volcano theory.

A new study from the UK piles more evidence on the asteroid side of the debate, while adding a new volcanic twist. These researchers say that volcanic activity actually helped life recover from the asteroid strike.

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During Mass Extinction Events, Volcanoes Were Releasing About the Same Amount of CO2 as We Are Today

The Mount Redoubt volcano in Alaska. Image Credit: By R. Clucas - http://pubs.usgs.gov/dds/dds-39/album.html and http://gallery.usgs.gov/photos/03_29_2013_otk7Nay4LH_03_29_2013_5#.UrvS2vfTnrc, Public Domain, https://commons.wikimedia.org/w/index.php?curid=5768911

200 million years ago, a mass extinction event wiped out about 76% of all species on Earth—both terrestrial and marine. That event was called the end-Triassic extinction, or the Jurassic-Triassic (J-T) extinction event. At that time, the world experienced many of the same things as Earth is facing now, including a warming climate and the acidification of the oceans.

A new paper shows that pulses of volcanic eruptions were responsible, and that those pulses released the same amount of CO2 as humans are releasing today.

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