A Brief Tour of the Universe

Question: Can you provide a brief tour of the major objects visible in the universe?

Sure. If you look out at the nighttime sky, what you see right away are a few bright things that are planets in our own solar system or possibly the Moon, which is a terrible thing. We hate to have the Moon because all that reflected light makes the sky bright; makes it hard to do astronomy for distant objects. So, the real black belt astronomers don’t like the Moon; don’t like the planets very much. But, if you go out at night, you’ll see stars. And the stars that you see emitted their light, tens or hundreds, or even thousands of years ago. The speed of light, which everybody thinks is so fast, is really extremely slow. And it’s what lets astronomers see back into the past. 

So, for example, the speed of light is a foot, that’s a unit of distance, used here in the United States and I believe also in Myanmar. It’s a foot in a nanosecond, or a billionth of a second. So, you never see things the way they are, you always see the past. You always see light that bounced off somebody 10 nanoseconds ago, or in the back of a big room a hundred nanoseconds ago. When you go outside, you’re seeing light that was emitted – the sunlight that was emitted eight minutes ago, light in the solar system maybe up to an hour ago. And when you look at the stars, even the nearby stars, even the bright stars, the light has been traveling to your for tens of years, or hundreds of years, or even thousands of years. So, without a telescope you can see in the past a few thousand years. And what happened in the 1920’s was that people began to realize that the system of stars that we are in, which is the Milky Way; the Milky Way Galaxy we call it today, which we see as a band of light in the summer sky because we’re looking at this system, which is a big flattened system; kind of like a pizza edge on, except we’re a pepperoni. We’re on the pizza. And so our view of it is really quite awkward. We don’t have a good perspective of the Milky Way Galaxy. But we know now that it’s roughly speaking 100,000 light years in dimension across our Milky Way. So that means it takes light 100,000 years to travel across that span of distance. And that’s really just the beginning.

What people discovered in the 1920’s was that our galaxy is just one of billions of galaxies out there. The distances between the galaxies are a few times their own diameter. So, if the galaxy is this big, then the distance to the next galaxy is kind of ten times the size of the galaxy. So, if this is 100,000 light years, the distance to the next galaxy is a few million light years. And that’s fairly accurate. The galaxy that you can see – there’s one galaxy you can see without a telescope, if you know where to look, with binoculars. And easy object in a small telescope, and that’s the Andromeda Galaxy, M31. And in the autumn sky you can pick it out. It’s kind of a fuzzy patch. What we know is that is as big a system as the one we live in. It’s as big as the Milky way; it looks like a little tiny fuzzy patch because it’s so far away. 

And that’s really just the beginning. That’s our local neighborhood a few million light years away. It turns out that with modern telescopes and the best instruments and the better detectors we have today, it’s not that hard to see things that are a few billion light years away, or to measure the light from them anyway. So, that’s a thousand times farther away, it means the objects appear a million times dimmer. But what has changed over time is that we have big telescopes that collect a lot of light, and we have detectors that are nearly perfect at measuring the light and turning it into an electronic signal. So, very similar to the detectors that are in digital cameras and so on; they are made of silicon they work pretty much the same way, but we take long time exposures and we add up the data very carefully. 

Anyway, we’re able to make this – the technology has enabled us to make this leap so that we can study the distant objects. And the reason why we want to do that is that the telescope is really a king of no nonsense time machine. It let’s you see the way things were in the past. Of course, it doesn’t let you see into the future. It only lets you see the past, but we can do that to distances of a billion light years, and even with some effort, to many billions of light years. And that’s important because the time since the beginning of cosmic expansion, since the beginning of the universe as we know it, the time of the Big Bang, we think is about 14 billion years ago. So the biggest distance that light could travel in that time is about 14 billion light years. And we can see things most of the way back. That means we’re not just guessing that the universe has changed over time. The universe has expanded over time; has it gotten elaborated over time due to the action of gravity pulling stuff together and stars making more complicated elements and all that stuff that’s happened over the past 14 billion years is not just a story, it’s a real history that we can observe.

Recorded on February 17, 2010
Interviewed by Austin \r\nAllen


What’s floating around out there in the cosmological zoo? The Harvard astronomer describes the major objects visible via telescope and the naked eye.

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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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