'Gaian Bottleneck Theory' Explains Why We Haven't Found Any Aliens

Life may have ended before it had a chance to begin. They're calling this solution to the Fermi Paradox the Gaian Bottleneck. It's not that life has never emerged in the universe — it just never had the chance to grow or evolve.

'Gaian Bottleneck Theory' Explains Why We Haven't Found Any Aliens


Are we alone in the universe? It would seem unlikely given the ingredients for growing life are out there. So, why hasn't it happened anywhere else that we know of with the exception of Earth?

Here we arrive at what's known as the Fermi Paradox. There are incalculable possibilities for another Earth to exist in the universe, but there's no evidence to support the existence of extraterrestrial life. This contradiction between probability and available evidence has led many scientists to attempt to explain why this is the case.

Bill Nye has his own ideas about the Fermi Paradox.

Why has humanity not uncovered evidence proving the existence of alien life?

Aditya Chopra and CharleY Lineweaver, astrobiologists from the Australian National University, proposed an explanation in a recent paper:

Life may have ended before it had a chance to begin.

They're calling this solution to the Fermi Paradox the Gaian Bottleneck. It's not that life has never emerged in the universe — it just never had the chance to grow or evolve.

Many planets may have the conditions to sustain life, but a dramatic shift in those conditions may cause the planet to become unstable. So, microbial life may not have had the chance to evolve into more complex forms. Four billion years ago, Mars may have been a habitable planet, until the planet lost its atmosphere.

"Early life is fragile, so we believe it rarely evolves quickly enough to survive. Most early planetary environments are unstable. To produce a habitable planet, lifeforms need to regulate greenhouse gases such as water and carbon dioxide to keep surface temperatures stable," said Chopra.

When we do start to visit other planets, it's possible we may find fossil evidence of extinct microbial life, Chopra says, “not from multicellular species such as dinosaurs or humanoids that take billions of years to evolve.”

Other scientists have chosen to be more optimistic, proposing that we haven't been able to detect alien messages because they encrypt their data. It may be that it's “indistinguishable from cosmic microwave background radiation,” according to whistleblower Edward Snowden.

KIC 8462852 gave us a taste of what it might feel like to have a neighbor in the universe. Even if said neighbor would have been around 1,481 light-years away (not exactly close enough to pop over to borrow some sugar). It's nice to think there's someone else out there succeeding at life, but the Kepler mission is not giving up the search. It may just take some time, says Nye, after all “[w]e’ve only been listening for other civilizations for 50 years, 70 years.” 

When we do find signs of life, let's just hope we find they're still intact.

***

Photo Credit: ESA / Handout / Getty

Natalie has been writing professionally for about 6 years. After graduating from Ithaca College with a degree in Feature Writing, she snagged a job at PCMag.com where she had the opportunity to review all the latest consumer gadgets. Since then she has become a writer for hire, freelancing for various websites. In her spare time, you may find her riding her motorcycle, reading YA novels, hiking, or playing video games. Follow her on Twitter: @nat_schumaker

A new study says it's okay to eat red meat. An immediate uproar follows.

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CRISPR therapy cures first genetic disorder inside the body

It marks a breakthrough in using gene editing to treat diseases.

Credit: National Cancer Institute via Unsplash
Technology & Innovation

This article was originally published by our sister site, Freethink.

For the first time, researchers appear to have effectively treated a genetic disorder by directly injecting a CRISPR therapy into patients' bloodstreams — overcoming one of the biggest hurdles to curing diseases with the gene editing technology.

The therapy appears to be astonishingly effective, editing nearly every cell in the liver to stop a disease-causing mutation.

The challenge: CRISPR gives us the ability to correct genetic mutations, and given that such mutations are responsible for more than 6,000 human diseases, the tech has the potential to dramatically improve human health.

One way to use CRISPR to treat diseases is to remove affected cells from a patient, edit out the mutation in the lab, and place the cells back in the body to replicate — that's how one team functionally cured people with the blood disorder sickle cell anemia, editing and then infusing bone marrow cells.

Bone marrow is a special case, though, and many mutations cause disease in organs that are harder to fix.

Another option is to insert the CRISPR system itself into the body so that it can make edits directly in the affected organs (that's only been attempted once, in an ongoing study in which people had a CRISPR therapy injected into their eyes to treat a rare vision disorder).

Injecting a CRISPR therapy right into the bloodstream has been a problem, though, because the therapy has to find the right cells to edit. An inherited mutation will be in the DNA of every cell of your body, but if it only causes disease in the liver, you don't want your therapy being used up in the pancreas or kidneys.

A new CRISPR therapy: Now, researchers from Intellia Therapeutics and Regeneron Pharmaceuticals have demonstrated for the first time that a CRISPR therapy delivered into the bloodstream can travel to desired tissues to make edits.

We can overcome one of the biggest challenges with applying CRISPR clinically.

—JENNIFER DOUDNA

"This is a major milestone for patients," Jennifer Doudna, co-developer of CRISPR, who wasn't involved in the trial, told NPR.

"While these are early data, they show us that we can overcome one of the biggest challenges with applying CRISPR clinically so far, which is being able to deliver it systemically and get it to the right place," she continued.

What they did: During a phase 1 clinical trial, Intellia researchers injected a CRISPR therapy dubbed NTLA-2001 into the bloodstreams of six people with a rare, potentially fatal genetic disorder called transthyretin amyloidosis.

The livers of people with transthyretin amyloidosis produce a destructive protein, and the CRISPR therapy was designed to target the gene that makes the protein and halt its production. After just one injection of NTLA-2001, the three patients given a higher dose saw their levels of the protein drop by 80% to 96%.

A better option: The CRISPR therapy produced only mild adverse effects and did lower the protein levels, but we don't know yet if the effect will be permanent. It'll also be a few months before we know if the therapy can alleviate the symptoms of transthyretin amyloidosis.

This is a wonderful day for the future of gene-editing as a medicine.

—FYODOR URNOV

If everything goes as hoped, though, NTLA-2001 could one day offer a better treatment option for transthyretin amyloidosis than a currently approved medication, patisiran, which only reduces toxic protein levels by 81% and must be injected regularly.

Looking ahead: Even more exciting than NTLA-2001's potential impact on transthyretin amyloidosis, though, is the knowledge that we may be able to use CRISPR injections to treat other genetic disorders that are difficult to target directly, such as heart or brain diseases.

"This is a wonderful day for the future of gene-editing as a medicine," Fyodor Urnov, a UC Berkeley professor of genetics, who wasn't involved in the trial, told NPR. "We as a species are watching this remarkable new show called: our gene-edited future."

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A new government report describes 144 sightings of unidentified aerial phenomena.

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