Did the sun really have an evil twin responsible for the death of the dinosaurs?

The results of this study help us better understand how stars are born and how they develop.


Astronomers studying stars find that all of the ones like our sun were born twins. So where's our sun's twin? Some scientists think it had one long ago, which they named Nemesis. There's even speculation that it might've killed off the dinosaurs.

Star systems containing two and even three stars are plentiful in our galaxy. In fact, the nearest system to ours, Alpha Centauri, is a three star system. For years, scientists have wondered about the abundance of binary star systems. Are the stars born together or does the gravity of one pull in another sometime after birth? The born together theory has been more popular among astronomers.

So what happened to Nemesis? If there was one, researchers believe it broke free and shot off into the Milky Way, vanishing into obscurity billions of years ago. Two astronomers recently changed how we view the birth of stars, including our own sun's, by studying a region of the Perseus molecular cloud.

This is an egg-shaped dust cloud 600 light years away. It's essentially a nursery for stars. We now know that stars born in the dense centers of such clouds are always born binary.

Stars are born in the dense hearts of dust clouds. NASA Jet Propulsion Lab. Caltech.

Researchers gathered data through radio and visual observations. The radio observations were made at the Very Large Array in New Mexico, while the visual ones took place at the James Clerk Maxwell Telescope in Hawaii. Astronomers observed 55 young stars in 24 systems. All of them were multi-star systems, most of them binary.

They also studied 45 single star systems. Steven Stahler is a research astronomer at UC, Berkeley. He's the co-author on this study. "The key here is that no one looked before in a systematic way at the relation of real young stars to the clouds that spawn them," Stahler said.

Sarah Sadavoy, of the Smithsonian Astrophysical Observatory, was the lead author. What she and Stahler discovered was that wide binary systems, where the stars were separated by at least 500 astronomical units (AU), were by far the youngest. 500 AU is quite long, about 17 times the distance from our sun to Neptune. Older binary systems are usually closer together, a mere 200 AU apart.

What Sadavoy and Stahler discovered was that binary stars, in the course of their development, either spin off from one another or shrink into a true binary. After running a series of computer simulations and mathematical models, the only results that fit with the data was, stars like our sun are always born binary. Within a million years, they either become part of the same system, or break apart to form their own.

Around 60% of binary systems eventually separate, the duo found. This isn't the first time the idea of our sun having a twin has popped up. The theory's been around for decades. But these two astronomers came at in a different way.

In most binary star systems, the stars first move far apart. Getty Images.

If Nemesis were true, its gravitational pull would intermittently interrupt the path of asteroids, sending them careening off toward Earth. Some speculate that such an interruption could have caused the cataclysm that wiped out the dinosaurs. Earth has a nasty habit of having extinction events every 27 million years. Could Nemesis be involved? The theory is mere speculation. We simply have no evidence to go on.

There's no sign of Nemesis ever existing, currently. What if our sun was born out of some sort of anomaly we aren't aware of? If Nemesis was ejected from our solar system, we would've found it by now. Most astronomers think that if the sun did have a twin, it probably fused with another star a long time ago, somewhere else in the Milky Way.

Sadavoy and Stahler also caution that these observations in the Perseus dust cloud should also be corroborated with observations in others as well. Also, astrophysicists must work toward understanding the physics behind star formation and a star's early development. What we see is a little circumstantial evidence, adding a tad more weight to the idea that our sun had a twin.

The study will soon be published in the journal Monthly Notices of the Royal Astronomical Society.

To learn more about the sun's evil twin, click here:

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Yale scientists restore brain function to 32 clinically dead pigs

Researchers hope the technology will further our understanding of the brain, but lawmakers may not be ready for the ethical challenges.

Still from John Stephenson's 1999 rendition of Animal Farm.
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  • Researchers at the Yale School of Medicine successfully restored some functions to pig brains that had been dead for hours.
  • They hope the technology will advance our understanding of the brain, potentially developing new treatments for debilitating diseases and disorders.
  • The research raises many ethical questions and puts to the test our current understanding of death.

The image of an undead brain coming back to live again is the stuff of science fiction. Not just any science fiction, specifically B-grade sci fi. What instantly springs to mind is the black-and-white horrors of films like Fiend Without a Face. Bad acting. Plastic monstrosities. Visible strings. And a spinal cord that, for some reason, is also a tentacle?

But like any good science fiction, it's only a matter of time before some manner of it seeps into our reality. This week's Nature published the findings of researchers who managed to restore function to pigs' brains that were clinically dead. At least, what we once thought of as dead.

What's dead may never die, it seems

The researchers did not hail from House Greyjoy — "What is dead may never die" — but came largely from the Yale School of Medicine. They connected 32 pig brains to a system called BrainEx. BrainEx is an artificial perfusion system — that is, a system that takes over the functions normally regulated by the organ. The pigs had been killed four hours earlier at a U.S. Department of Agriculture slaughterhouse; their brains completely removed from the skulls.

BrainEx pumped an experiment solution into the brain that essentially mimic blood flow. It brought oxygen and nutrients to the tissues, giving brain cells the resources to begin many normal functions. The cells began consuming and metabolizing sugars. The brains' immune systems kicked in. Neuron samples could carry an electrical signal. Some brain cells even responded to drugs.

The researchers have managed to keep some brains alive for up to 36 hours, and currently do not know if BrainEx can have sustained the brains longer. "It is conceivable we are just preventing the inevitable, and the brain won't be able to recover," said Nenad Sestan, Yale neuroscientist and the lead researcher.

As a control, other brains received either a fake solution or no solution at all. None revived brain activity and deteriorated as normal.

The researchers hope the technology can enhance our ability to study the brain and its cellular functions. One of the main avenues of such studies would be brain disorders and diseases. This could point the way to developing new of treatments for the likes of brain injuries, Alzheimer's, Huntington's, and neurodegenerative conditions.

"This is an extraordinary and very promising breakthrough for neuroscience. It immediately offers a much better model for studying the human brain, which is extraordinarily important, given the vast amount of human suffering from diseases of the mind [and] brain," Nita Farahany, the bioethicists at the Duke University School of Law who wrote the study's commentary, told National Geographic.

An ethical gray matter

Before anyone gets an Island of Dr. Moreau vibe, it's worth noting that the brains did not approach neural activity anywhere near consciousness.

The BrainEx solution contained chemicals that prevented neurons from firing. To be extra cautious, the researchers also monitored the brains for any such activity and were prepared to administer an anesthetic should they have seen signs of consciousness.

Even so, the research signals a massive debate to come regarding medical ethics and our definition of death.

Most countries define death, clinically speaking, as the irreversible loss of brain or circulatory function. This definition was already at odds with some folk- and value-centric understandings, but where do we go if it becomes possible to reverse clinical death with artificial perfusion?

"This is wild," Jonathan Moreno, a bioethicist at the University of Pennsylvania, told the New York Times. "If ever there was an issue that merited big public deliberation on the ethics of science and medicine, this is one."

One possible consequence involves organ donations. Some European countries require emergency responders to use a process that preserves organs when they cannot resuscitate a person. They continue to pump blood throughout the body, but use a "thoracic aortic occlusion balloon" to prevent that blood from reaching the brain.

The system is already controversial because it raises concerns about what caused the patient's death. But what happens when brain death becomes readily reversible? Stuart Younger, a bioethicist at Case Western Reserve University, told Nature that if BrainEx were to become widely available, it could shrink the pool of eligible donors.

"There's a potential conflict here between the interests of potential donors — who might not even be donors — and people who are waiting for organs," he said.

It will be a while before such experiments go anywhere near human subjects. A more immediate ethical question relates to how such experiments harm animal subjects.

Ethical review boards evaluate research protocols and can reject any that causes undue pain, suffering, or distress. Since dead animals feel no pain, suffer no trauma, they are typically approved as subjects. But how do such boards make a judgement regarding the suffering of a "cellularly active" brain? The distress of a partially alive brain?

The dilemma is unprecedented.

Setting new boundaries

Another science fiction story that comes to mind when discussing this story is, of course, Frankenstein. As Farahany told National Geographic: "It is definitely has [sic] a good science-fiction element to it, and it is restoring cellular function where we previously thought impossible. But to have Frankenstein, you need some degree of consciousness, some 'there' there. [The researchers] did not recover any form of consciousness in this study, and it is still unclear if we ever could. But we are one step closer to that possibility."

She's right. The researchers undertook their research for the betterment of humanity, and we may one day reap some unimaginable medical benefits from it. The ethical questions, however, remain as unsettling as the stories they remind us of.

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