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Could modern humans survive an asteroid impact, like what killed the dinosaurs?
If the bolide had hit just 30 seconds later, we’d be looking at a very different Earth.
We know that an enormous meteorite hit the Gulf of Mexico some 66 million of years ago, shooting dangerous gases, dust, and debris into the upper atmosphere, blotting out the sun, and killing off most of the plant life on Earth. Large herbivores followed and eventually the carnivores that preyed upon them. Note however that one recent, exhaustive study found that many of the dinosaurs were already in decline, way before the bolide or meteorite’s impact.
Had the asteroid hit just 30 seconds later (or sooner), landing more in the Atlantic or Pacific, rather than just off the coast of Mexico, we may have had more, non-avian dinosaurs running around today. Instead, the bolide smashed into the Earth with a force equivalent to ten billion nuclear bombs.
Our ancient, tiny mammalian ancestors survived, their rodent-like bodies cowering as they witnessed one of the greatest mass extinction events ever to occur on our planet. Of course, they probably didn’t have brains developed enough to fully comprehend it. Besides the stench of death filling the air and the massive bodies piling up hither and yon, acid rain fell and volcanic eruptions shook the Earth, sullied the air, and scarred the landscape.
Smallness and requiring little food helped our ancient, shrew-like ancestors survive, which begs the question, could we modern humans make out okay if such an event happened today? Research surrounding another, similar incident suggests so, but it’s complicated. Around 790,000 years ago another asteroid about a kilometer (approx. 0.62 mi) long struck the Earth with such a force that it sent debris hurtling into the atmosphere, which ended up covering one tenth of the Earth’s surface. The crater has yet to be found. Scientists say it would be about 40–100 km (approx. 24-62 mi) in diameter.
The impact site of the meteorite that struck nearly 800,000 years ago hasn’t been found. Credit: By USGS/D. Roddy.
What’s been unearthed are these glassy rocks called tektites. Larger varieties can weigh up to 20 kilograms (44 lbs.). Scientists recently analyzed these stones. Their findings were published in the journal Geology. This was the largest such event to occur during the time when humans were known to be on Earth and evolving (as they always are). Researchers say the event gives us clues as to whether modern humans could survive a dinosaur-size cataclysm today. The answer is yes, but it would be difficult.
So far, tektites have been found in Australia, Asia, and Antarctica. In this study, astrobiologist and geochemist Aaron Cavosie of Curtin University in Australia, along with colleagues, looked into the chemical makeup of three tektites found in Thailand. Researchers studied minute crystals of zircon, each about the width of a human hair, within the tektites.
These showed signs of the rare mineral reidite, which disappears seconds after being formed. “Reidite requires substantially higher shock pressures to form,” Cavosie said. High temperatures are needed as well. The orientation of the zircon in the tektites points to an impact occurring somewhere in Southeast Asia, probably near Thailand. Though these samples tell a lot, what’s missing is the exact location of the impact site. It’s mind-boggling that such a large crater has yet to be found.
Tektite found in the Libyan Desert. Credit: James St. John. Flickr.
“Our not-too-distant ancestors witnessed this impact,” Cavosie said. “They might have been dragging their knuckles, but an event like the formation of a 50- to 100-kilometer-diameter impact is sure to have gotten their attention.” Further studies examining tektites may yet reveal the crater’s location.
Even though this was a catastrophic event, our ancestors were able to survive and thrive, as the debris shot up into the atmosphere must've caused significant changes to the climate. How this influenced our ancestors and perhaps changed the course of human evolution is difficult to discern, though more clues may help us get a better understanding of that.
So what if a comet or a serious asteroid collided with the Earth? Most scientists say our planet is threatened by such an asteroid about every million years or so. We’re not due for one any time soon. Most of the asteroids out there lie between Mars and Jupiter and won’t threaten Earth ever.
There are thousands though which could potentially hit us. Most are the size of a compact car or smaller and burn up in the atmosphere. A few are a bit larger and could do great damage to say a house or even a city, depending on the size, but wouldn’t threaten all life on Earth or anything.
NASA’s Planetary Defense Coordination Office (PDCO) tracks near-Earth objects (NEOs) of significant size with the potential to hit our planet. It’s a collaborative effort involving observatories and universities all over the world. The perennial question is whether or not an asteroid looks as if it’s inside the “keyhole,” meaning it has the potential to make impact with Earth.
If a serious meteorite were to hit the Earth, would we survive? Credit: Comfreak, Pixababy.
Besides a collision, a sizeable object passing close by the Earth could throw the planet’s orbit off. So far, deflection strategies haven’t been decided upon. Planting a nuclear bomb inside a potentially hazardous asteroid, or nudging it off course with rockets or a solar sail, are some other the methods that have been proposed.
Should we fail and a large asteroid once again crash into our world, causing a long-term impact winter, most of the plant life would die off within weeks. Large trees could last decades due to a buildup of sugar in their systems and a slow metabolism. Not much life would exist beyond that, save for microbes and small creatures.
Humans could survive if they went deep underground to take advantage of heat found there, or if we built isolated habitats inside domes. Of course, it’s best to safeguard our precious planet. And although attaching a solar sail to an asteroid may sound fantastical, most scientists believe it’s feasible, using technology that’s already available today.
To learn more about how NASA would handle a deadly asteroid, click here:
These alien-like creatures are virtually invisible in the deep sea.
- A team of marine biologists used nets to catch 16 species of deep-sea fish that have evolved the ability to be virtually invisible to prey and predators.
- "Ultra-black" skin seems to be an evolutionary adaptation that helps fish camouflage themselves in the deep sea, which is illuminated by bioluminescent organisms.
- There are likely more, and potentially much darker, ultra-black fish lurking deep in the ocean.
The Pacific blackdragon
Credit: Karen Osborn/Smithsonian<p>When researchers first saw the deep-sea species, it wasn't immediately obvious that their skin was ultra-black. Then, marine biologist Karen Osborn, a co-author on the new paper, noticed something strange about the photos she took of the fish.</p><p style="margin-left: 20px;">"I had tried to take pictures of deep-sea fish before and got nothing but these really horrible pictures, where you can't see any detail," Osborn told <em><a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">Wired</a></em>. "How is it that I can shine two strobe lights at them and all that light just disappears?"</p><p>After examining samples of fish skin under the microscope, the researchers discovered that the fish skin contains a layer of organelles called melanosomes, which contain melanin, the same pigment that gives color to human skin and hair. This layer of melanosomes absorbs most of the light that hits them.</p>
A crested bigscale
Credit: Karen Osborn/Smithsonian<p style="margin-left: 20px;">"But what isn't absorbed side-scatters into the layer, and it's absorbed by the neighboring pigments that are all packed right up close to it," Osborn told <em>Wired</em>. "And so what they've done is create this super-efficient, very-little-material system where they can basically build a light trap with just the pigment particles and nothing else."</p><p>The result? Strange and terrifying deep-sea species, like the crested bigscale, fangtooth, and Pacific blackdragon, all of which appear in the deep sea as barely more than faint silhouettes.</p>
David Csepp, NMFS/AKFSC/ABL<p>But interestingly, this unique disappearing trick wasn't passed on to these species by a common ancestor. Rather, they each developed it independently. As such, the different species use their ultra-blackness for different purposes. For example, the threadfin dragonfish only has ultra-black skin during its adolescent years, when it's rather defenseless, as <em>Wired</em> <a href="https://www.wired.com/story/meet-the-ultra-black-vantafish/" target="_blank">notes</a>.</p><p>Other fish—like the <a href="http://onebugaday.blogspot.com/2016/06/a-new-anglerfish-oneirodes-amaokai.html" target="_blank">oneirodes species</a>, which use bioluminescent lures to bait prey—probably evolved ultra-black skin to avoid reflecting the light their own bodies produce. Meanwhile, species like <em>C. acclinidens</em> only have ultra-black skin around their gut, possibly to hide light of bioluminescent fish they've eaten.</p><p>Given that these newly described species are just ones that this team found off the coast of California, there are likely many more, and possibly much darker, ultra-black fish swimming in the deep ocean. </p>
Using machine-learning technology, the genealogy company My Heritage enables users to animate static images of their relatives.
- Deep Nostalgia uses machine learning to animate static images.
- The AI can animate images by "looking" at a single facial image, and the animations include movements such as blinking, smiling and head tilting.
- As deepfake technology becomes increasingly sophisticated, some are concerned about how bad actors might abuse the technology to manipulate the pubic.
My Heritage/Deep Nostalgia<p>But that's not to say the animations are perfect. As with most deep-fake technology, there's still an uncanny air to the images, with some of the facial movements appearing slightly unnatural. What's more, Deep Nostalgia is only able to create deepfakes of one person's face from the neck up, so you couldn't use it to animate group photos, or photos of people doing any sort of physical activity.</p>
My Heritage/Deep Nostalgia<p>But for a free deep-fake service, Deep Nostalgia is pretty impressive, especially considering you can use it to create deepfakes of <em>any </em>face, human or not. </p>
How long should one wait until an idea like string theory, seductive as it may be, is deemed unrealistic?
- How far should we defend an idea in the face of contrarian evidence?
- Who decides when it's time to abandon an idea and deem it wrong?
- Science carries within it its seeds from ancient Greece, including certain prejudices of how reality should or shouldn't be.
Plato used the allegory of the cave to explain that what humans see and experience is not the true reality.
Credit: Gothika via Wikimedia Commons CC 4.0<p>When scientists and mathematicians use the term <em>Platonic worldview</em>, that's what they mean in general: The unbound capacity of reason to unlock the secrets of creation, one by one. Einstein, for one, was a believer, preaching the fundamental reasonableness of nature; no weird unexplainable stuff, like a god that plays dice—his tongue-in-cheek critique of the belief that the unpredictability of the quantum world was truly fundamental to nature and not just a shortcoming of our current understanding. Despite his strong belief in such underlying order, Einstein recognized the imperfection of human knowledge: "What I see of Nature is a magnificent structure that we can comprehend only very imperfectly, and that must fill a thinking person with a feeling of humility." (Quoted by Dukas and Hoffmann in <em>Albert Einstein, The Human Side: Glimpses from His Archives</em> (1979), 39.)</p> <p>Einstein embodies the tension between these two clashing worldviews, a tension that is still very much with us today: On the one hand, the Platonic ideology that the fundamental stuff of reality is logical and understandable to the human mind, and, on the other, the acknowledgment that our reasoning has limitations, that our tools have limitations and thus that to reach some sort of final or complete understanding of the material world is nothing but an impossible, <a href="https://www.amazon.com/dp/B01K2JTGIA?tag=bigthink00-20&linkCode=ogi&th=1&psc=1" target="_blank" rel="noopener noreferrer">semi-religious dream</a>.</p>