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“I do think there is a time when sexuality in space is going to have to be addressed,” said Paul Root Wolpe, the Director of Emory University’s Center for Ethics and a senior bioethicist at NASA. “I do not know if NASA has an official policy on sex in space, [but] there will be a time when NASA needs to make some policies or understandings about those kinds of relationships. There is a point where the length of time [on a mission] becomes part of the question of whether or not it’s fair to deprive people of this aspect of being human. I’m just not sure it’s time yet.”
Aside from the lack of urgent scientific reasons to really test human libido and sexual behavior in orbit, the simple fact of the matter is that body-to-body docking in microgravity is probably not as orgasmic as we might imagine it to be. In the first place, there are significant logistical difficulties in orchestrating the deed, and this alone, Wolpe suggested, might be reason enough to dissuade astronauts from unofficial experimentation.
“A lot of people think that sex in microgravity will be great because by losing gravity you can move in ways you can’t terrestrially. The [scientists] who’ve thought about this aren’t so sure about that at all,” he said. “One of the things that gravity helps us do is stay together, so sex in microgravity might actually be more difficult because you’re going to have to make sure that you’re always holding each other so you don’t drift apart. It might be a lot more challenging and a lot less fulfilling than most people think.”
Even if the logistical difficulties of space sex can be settled, there’s still the problem that microgravity makes sex, well, significantly less sexy.
Astronauts tend to sweat more in space, and decreased blood pressure could make it more difficult for males to hold up their end of the mission. As for the female side of things, the jury is still out on whether microgravity is a bane or a boon to boobs.
The Hubble Space Telescope just calculated the distance to the most far-out galaxy ever measured, providing scientists with a look deep into the history of the universe.
The far-away galaxy, named GN-z11, existed a mere 400 million years after the Big Bang, or about 13.3 billion years ago. Because the light from such a distant galaxy must travel huge distances to reach Earth, scientists are seeing the galaxy as it looked over 13 billion years ago. You can see the galaxy in this video from the Hubble Telescope team.
"We've taken a major step back in time, beyond what we'd ever expected to be able to do with Hubble. We managed to look back in time to measure the distance to a galaxy when the universe was only 3 percent of its current age," Pascal Oesch, an astronomer at Yale University and lead author of the research paper announcing the new measurement, said in a statement from the Hubble European Space Agency Information Centre in Germany.
Measuring the distance to an extremely far-off cosmic object poses many challenges to scientists, including the fact that the universe is expanding, and has been expanding for nearly all of time. Any distance measurement must take into account exactly how much the space between objects has stretched since an object's light left and traveled to Earth.
This can get quite complicated. So instead of talking about the distance to cosmic objects in terms of miles, astronomers and astrophysicists will more often refer to when the object existed in the history of the universe.
To determine this for GN-z11, scientists measured the degree to which the light from the galaxy has been shifted by the expanding universe, known as redshift. A higher redshift indicates a more distant object. Previously, the highest redshift ever measured was from the galaxy EGSY8p7, whose redshift was 8.68. The GN-z11 galaxy's newly measured redshift is a whopping 11.1.
The Dark Ages
If GN-z11 existed 400 million years after the Big Bang, then it belongs to the very first population of stars and galaxies to form in the cosmos. At that time, the universe was just emerging from a period known as the Dark Ages.
"The previous record-holder was seen in the middle of the epoch when starlight from primordial galaxies was beginning to heat and lift a fog of cold, hydrogen gas," said Rychard Bouwens from the University of Leiden in the Netherlands and a co-author on the new paper. "This transitional period is known as the re-ionisation era. GN-z11 is observed 150 million years earlier, near the very beginning of this transition in the evolution of the Universe."
GN-z11 is 25 times smaller than the Milky Way galaxy and has only about 1 percent the total stellar mass of the Milky Way, observations by Hubble at the Spitzer Space Telescope have revealed, the statement said.
"It's amazing that a galaxy so massive existed only 200 million to 300 million years after the very first stars started to form," said Garth Illingworth of the University of California, Santa Cruz, a coauthor on the new research paper. "It takes really fast growth, producing stars at a huge rate, to have formed a galaxy that is a billion solar masses so soon."
GNz11 is forming stars at 20 times the current rate of the Milky Way, the statement said, which is part of why the distant galaxy is bright enough to be observed by telescopes like Hubble and Spitzer.
Marijn Franx, a member of the team from the University of Leiden, said in the statement that previous work suggested galaxies as bright as GN-z11 should not have been able to form at such an early point in the universe's history.
"The discovery of GN-z11 showed us that our knowledge about the early universe is still very restricted," said Ivo Labbe, also of the University of Leiden and a co-author on the paper. "How GN-z11 was created remains somewhat of a mystery for now. Probably we are seeing the first generations of stars forming around black holes."
Researchers said the find provides a hint at the new information that will be revealed by the James Webb Space Telescope, which is set to launch in 2018. The primary mirror on JWST is 16.4 feet (5.4 meters) wide, compared to Hubble's 7.8-foot-wide (2.4 m) mirror.
The new research paper will be published in the Astrophysical Journal. [Reply]
Originally Posted by Anyong Bluth:
We're both messed up.
There was a news story about his mission on a couple of days ago, and almost immediately that question popped into my head.
He has to whack off. How could you go a whole year? Does he get privacy? Does he get to snapchat the splooge going across the galaxy? So many questions for the press conference.... [Reply]
“Little pig, little pig, let me come in,” says the big, bad wolf. “No, no, not by the hair on my chinny chin chin,” say the three little pigs. This scene is deeply unrealistic and not just because of the pigs' architectural competence, the wolf's implausible lung capacity, and everyone's ability to talk.
The thing is: Pigs don't have chins. Nor do any animals, except for us.
The lower jaw of a chimpanzee or gorilla slopes backwards from the front teeth. So did the jaw of other hominids like Homo erectus. Even Neanderthal jaws ended in a flat vertical plane. Only in modern humans does the lower jaw end in a protruding strut of bone. A sticky-outy bit. A chin.
“It's really strange that only humans have chins,” says James Pampush from Duke University. “When we're looking at things that are uniquely human, we can't look to big brains or bipedalism because our extinct relatives had those. But they didn't have chins. That makes this immediately relevant to everyone.” Indeed, except in rare cases involving birth defects, everyone has chins. Sure, some people have less pronounced ones than others, perhaps because their lower jaws are small or they have more flesh around the area. But if you peeled back that flesh and exposed their jawbones—and maybe don't do that—you'd still see a chin.
So, why do chins exist?
There are no firm answers, which isn't for lack of effort. Evolutionary biologists have been proposing hypotheses for more than a century, and Pampush has recently reviewed all the major ideas, together with David Daegling. “We kept showing, for one reason or another, that these hypotheses are not very good,” he says.
The most heavily promoted explanation is that chins are adaptations for chewing—that they help to reduce the physical stresses acting upon a masticating jaw. But Pampush found that, if anything, the chin makes things worse. The lower jaw consists of two halves that are joined in the middle; when we chew, we compress the bone on the outer face of this join (near the lips) and pull on the bone on the inner face (near the tongue). Since bone is much stronger when compressed than pulled, you'd ideally want to reinforce the inner face of the join and not the outer one. In other words, you'd want the opposite of a chin.
Others have suggested that the chin is an adaptation for chinwags: It resists the forces we create when speaking. After all, speech is certainly a feature that separates us from other living animals. But there's no good evidence that the tongue exerts substantial enough forces to warrant a thick chunk of reinforcing bone. “And any mammal that also communicates vocally or suckles or engages in complex feeding behaviors that involve the tongue are probably experiencing similar stresses and strains, and they're not getting chins,” says Pampush.
Maybe it's about sex, then? Men typically have bigger chins than women, and stronger chins are often equated with attractiveness. Perhaps the chin is a sexual ornament, the human equivalent of a stag's antlers or a peacock's tail, a way of attracting mates or perhaps even signaling one's health and quality. “But if that's the case, we'd be the only mammal ever where both sexes have selected for the exact same ornament,” says Pampush. In other words, women have chins, too. Chin shape may well be relevant to sex, but that doesn't explain chin presence. “They must have been there for some other reason before we started looking at the shape of them.”
Then, there are hypotheses that “stretch the concept of natural selection,” says Pampush. For example, one century-old idea says that chins are adaptations for deflecting punches to the face. That is, they helped early humans to take one on the chin. “That would require humans to hit each other so often, and to suffer such dire consequences from being hit without a chin ... it's unrealistic,” says Pampush. Also, chins are terrible for deflecting blows. They don't disperse the incoming forces very evenly, which results in broken jaws. Even if our ancestors were constantly pummeling each other in the face, they would have fared better by reinforcing their jaws all the way round.
Pampush doubts that chins are adaptations at all. He thinks it's more likely that they are spandrels—incidental features that have no benefits in themselves, but are byproducts of evolution acting upon something else.
For example, during human evolution, our faces shortened and our posture straightened. These changes made our mouths more cramped. To give our tongues and soft tissues more room, and to avoid constricting our airways, the lower jaw developed a forward slope, of which the chin was a side effect. The problem with this idea is that the chin's outer face doesn't follow the contours of its inner face, and has an exceptionally thick knob of bone. None of that screams “space-saving measure.”
A different explanation portrays the chin as a bit of the jaw that got left behind while the rest shrunk back. As early humans started cooking and processing our food, we made fewer demands upon our teeth, which started shrinking as a result. They gradually retracted into the face, while the part of the lower jaw that held them did not (or, at least, did so more slowly). Hence: chin.
Stephen Jay Gould and Richard Lewontin, who coined the concept of evolutionary spandrels, liked this hypothesis. So does Nathan Holton from the University of Iowa, who studies facial evolution. “It seems that the appearance of the chin itself is probably related to patterns of facial reduction in humans during the Pleistocene,” he says. “In this sense, understanding why faces became smaller is important to explaining why we have chins.”
“But why did the lower border of the jaw also not shrink?” Pampush asks. “What happened that left that last little bit sticking out?” This is the problem with spandrel hypotheses more generally: They're often very hard to test.
It may seem frustrating to have so many imperfect competing hypotheses, but that's part of the joy of chins: They reveal something about how scientists think about evolution. Some see the sculpting power of natural selection in everything, and view chins as surely some kind of adaptation. Others see natural selection as just one of many evolutionary forces, and so gravitate towards a spandrel-based explanation. “The chin is one of these rare phenomena in evolutionary biology that really exposes the deep philosophical differences between researchers in the field,” says Pampush.
And, indeed, between people outside the field. “I always get entertaining emails from lay people trying to help me so let me thank you in advance for what I'm about to receive,” he tells me.
Because if there's one trait that more universally human than the chin, it's having opinions. [Reply]
I know this was a big deal when I was growing up. A doctor once told my mom that if I had any more x-rays she should consider making me quit sports. I broke myself frequently.
The widespread belief that radiation from X rays, CT scans and other medical imaging can cause cancer is based on an unproven, decades-old theoretical model, according to a study published in the American Journal of Clinical Oncology.
The model, known as linear no-threshold (LNT), is used to estimate cancer risks from low-dose radiation such as medical imaging. But risk estimates based on this model "are only theoretical and, as yet, have never been conclusively demonstrated by empirical evidence," corresponding author James Welsh, MD and colleagues write. Use of the LNT model drives unfounded fears and "excessive expenditures on putative but unneeded and wasteful safety measures."
Dr. Welsh is a Loyola University Medical Center radiation oncologist and a professor in the Department of Radiation Oncology of Loyola University Chicago Stritch School of Medicine.
The LNT model dissuades many physicians from using appropriate imaging techniques and "discourages many in the public from getting proper and needed imaging, all in the name of avoiding any radiation exposure," Dr. Welsh and colleagues write.
The authors reexamined the original studies, dating back more than 70 years, which led to adoption of the LNT model. This reappraisal found that the data reported in those studies do not actually support the LNT model.
In the LNT model, the well-established cancer-causing effects of high doses of radiation are extended downward in a straight line to very low doses. The LNT model assumes there is no safe dose of radiation, no matter how small. However, the human body has evolved the ability to repair damage from low-dose radiation that naturally occurs in the environment.
The LNT model dates to studies, conducted in the 1940s, of fruit flies exposed to various doses of radiation. The scientists who conducted those studies concluded there is no safe level of radiation, thus giving rise to the LNT model that is used to this day. But their conclusion was unwarranted because their experiments had not been done at truly low doses. A study exposing fruit flies to low-dose radiation wasn't conducted until 2009, and this study did not support the LNT model.
Studies of atomic bomb survivors and other epidemiological studies of human populations have never conclusively demonstrated that low-dose radiation exposure can cause cancer.
Any claim that low-dose radiation from medical imaging procedures is known to cause cancer "should be vigorously challenged, because it serves to alarm and perhaps harm, rather than educate," Dr. Welsh and colleagues write.
The authors conclude the LNT model "should finally and decisively be abandoned."
The study is titled "The birth of the illegitimate linear no-threshold model -- an invalid paradigm for estimating risk following low-dose radiation exposure." [Reply]
