UFO'S of UAP'S, ASTRONOMIE, RUIMTEVAART, ARCHEOLOGIE, OUDHEIDKUNDE, SF-SNUFJES EN ANDERE ESOTERISCHE WETENSCHAPPEN

Stem cell technology has advanced so much that scientists can grow miniature versions of human brains — called organoids, or mini-brains if you want to be cute about it — in the lab, but medical ethicists are concerned about recent developments in this field involving the growth of these tiny brains in other animals. Those concerns are bound to become more serious after the annual meeting of the Society for Neuroscience starting November 11 in Washington, D.C., where two teams of scientists plan to present previously unpublished research on the unexpected interaction between human mini-brains and their rat and mouse hosts.

In the new papers, according to STAT, scientists will report that the organoids survived for extended periods of time — two months in one case — and even connected to lab animals’ circulatory and nervous systems, transferring blood and nerve signals between the host animal and the implanted human cells. This is an unprecedented advancement for mini-brain research.

“We are entering totally new ground here,” Christof Koch, president of the Allen Institute for Brain Science in Seattle, told STAT. “The science is advancing so rapidly, the ethics can’t keep up.”

DMT receptors in mini-brain organoids.

That mini-brains can even be grown in the lab is a huge advancement in the first place, as they have many of the same characteristics as living human brains that are in the early stages of development. Though they’re not “alive” in the same sense that you and I are, they grow and are organized into different layers like our brains are. They even react in similar ways to stimuli like psychedelic drugs. Organoids are poised to revolutionize research on the human brain since scientists can perform tests on them that would be unethical to attempt on living humans.

Scientists have debated whether these brains are “conscious,” but the fact that they could be successfully implanted in lab animals raises a whole new set of ethical concerns for the researchers who work with them. One of the major concerns in the mini-brain scenario is that these organoids could grow to more advanced levels within lab animals, making the debate about mini-brain consciousness much more urgent.

In Salk Institute experiments, human stem cells were pipetted into a pig embryo.

Putting human brain structures into non-human animals creates a thorny ethical area that raises people’s fears about medical research going too far into unfamiliar territory — and too quickly. It’s likely to be a recurring theme in this field, too. In January, Salk Institute researchers developed human-pig chimeras, creating the possibility that pigs with human brain cells might also develop human consciousness.

STAT also reports that a third lab, in addition to the two presenting at the Society for Neuroscience meeting, has successfully connected human brain organoids to blood vessels. This attempt veered into such challenging ethical territory, though, that the lab reportedly paused its efforts.

If you liked this article, check out this video on how LSD affects the brain.

Photos via Dakic et al, Juan Carlos Izpisua Belmonte, The Salk Institute, Flickr / fbobolas

This artist's illustration shows comet fragments crossing the face of a star, one possible explanation for the strange dimming exhibited by "Boyajian's star."

Credit: NASA/JPL-Caltech

In 1960, physicist Freeman Dyson proposed that a sufficiently advanced civilization could build a sphere around a star and would be able to capture all the star's radiant energy (Earthbound observers would see it re-radiated it as infrared light, so the star would look like a giant heat source). But Tabby's star is clearly not surrounded by a solid sphere, since we can see the star's light. The kind of alien megastructure that one might imagine around this star would be a swarm of small bodies arranged in a spherical formation, or perhaps some large object or set of objects that regularly passes in front of the star. [Dyson Spheres: How Advanced Alien Civilizations Would Conquer the Galaxy (Infographic)]

By surrounding their star with swarms of energy-collecting satellites, advanced civilizations could create Dyson spheres. [Read the Full Dyson Sphere Infographic Here.]

Credit: By Karl Tate, Infographics Artist

The former is called a Dyson swarm, and would be easier to build than a sphere. If the star was surrounded by a Dyson swarm, each satellite would have to be at least asteroid-size, and you'd need many thousands of them. If they are orbiting at distances comparable to our own solar system's inner planets, their periods, or the time it takes them to make one revolution around their host star, would be anywhere from a few months to a few years, following Kepler's laws of planetary motion.

Could Tabby's star be surrounded by a ring-shaped structure a la Larry Niven's "Ringworld" novels? Such a ring, if built around the sun, would have to be about 93 million miles (149 million km) in radius, or about 584 million miles (940 million km) in circumference. That's so large that no known material could survive the stresses; Niven had to come up with a fictional material called scrith. Astrophysicist Katie Mack, told the BBC that you'd need something that was bound more strongly than ordinary molecular bonds. Niven's books posit a Ringworld that is about 1 million miles (1.6 million km) wide, large enough that it would block the light from its parent star if it was in the line of sight of an observer. But the pattern of eclipsing light from Tabby's star doesn't seem to fit what you'd see with a ring; the dimming wouldn't show the irregularities that it does with such a structure, according to Mack.

One could imagine a vast Dyson ring, though, with miles-wide satellites placed at intervals around Tabby's star. But in this case, too, to be at all visible, the satellites would need to be orders of magnitude larger than any space habitat humans have ever attempted to build or colonize, according to Mack — even the ISS is only 368 feet (108 meters) across, and that's far too small to be visible even from as "close" as Mars, let alone light years distant.

The smallest exoplanet that Kepler has found so far is larger than Earth's moon. Called Kepler 37b, it's also a lot closer to Earth than Tabby's star is, only 215 light-years distant. If Tabby's star is surrounded by satellites, they would have to be even bigger than the Death Star from "Star Wars," which is stated in various franchise-related sources as being 60 miles (100 kilomters) across. ['Star Wars' Tech: 8 Sci-Fi Inventions and Their Real-Life Counterparts]

So why don't scientists think aliens are the explanation for the dimming of Tabby's star? One reason is that an alien megastructure would give off radiation in the infrared in a specific way. Any object that gets lit by a nearby star reflects some light and absorbs the rest, and that absorbed light gets re-emitted in a longer wavelength. Basically, objects warm up. In a talk at the Search for Extraterrestrial Intelligence (SETI) Institute in Mountain View, California, in August 2016, astronomer Jason Wright of Penn State University said studies of the star's light have shown no sign of such "waste heat" with Tabby's star.

The other issue is that such megastructures would be difficult to keep stable. A swarm of satellites orbiting would eventually settle into a disk-like arrangement absent active controls, because any object orbiting another or rotating experiences some centripetal force – this is why the Earth is slightly flattened. The same is true for Dyson rings and swarms. Futurist Anders Sandberg notes on his site outlining Dyson sphere principles that one structure that might stay stable is a Dyson bubble, made of gigantic, miles-square satellites that stay in place because of radiation pressure, in huge solar sails. But to stay in place, those satellites would have to be stationary with respect to the parent star, so they wouldn't cause anomalous dimming over time as was seen with Tabby's star. µ