The divided, 4-3 ruling cited factors that have come up in other states to abolish the death penalty including racial and economic disparities in its use, the costs involved with appeals, the cruelty of the wait for execution and the risk of executing innocent people.Read the rest
At his Psychology Today blog, Michael Chorost delves into a question about exoplanets that I've not really thought much about before — how easy they would be to leave.
Many of the potentially habitable exoplanets that we've found — the ones we call "Earth-like" — are actually a lot bigger than Earth. That fact has an effect — both on how actually habitable those planets would be for us humans and how easily any native civilizations that developed could slip the surly bonds of gravity and make it to outer space.
The good news, says Chorost is that the change in surface gravity wouldn't be as large as you might guess, even for planets much bigger than Earth. The bad news: Even a relatively small increase in surface gravity can mean a big increase in how fast a rocket would have to be going in order to leave the planet. It starts with one equation — SG=M/R^2.
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Let’s try it with [exoplanet] HD 40307g, using data from the Habitable Exoplanet Catalog. Mass, 8.2 Earths. Radius, 2.4 times that of Earth. That gets you a surface gravity of 1.42 times Earth.
... it’s amazingly easy to imagine a super-Earth with a comfortable gravity. If a planet had eight Earth masses and 2.83 times the radius, its surface gravity would be exactly 1g. This is the “Fictional Planet” at the bottom of the table. Fictional Planet would be huge by Earth standards, with a circumference of 70,400 miles and an area eight times larger.
I really enjoyed reading a recent story in The New York Times Magazine about attempts to understand extreme longevity — the weird tendency for certain populations to have larger-than-average numbers of people who live well into their 90s, if not 100s.
Written by Dan Buettner, the piece focuses on the Greek island of Ikaria, and, in many ways, it's a lot like a lot of the other stories I've read on this subject. From a scientific perspective, we don't really understand why some people live longer than others. And we definitely don't understand why some populations have more people who live longer. There are lots of theories. Conveniently, they tend to coincide with our own biases about what we currently think is most wrong with our own society. So articles about extremely long-lived populations tend to offer a lot of inspiring stories, some funny quotes from really old people, and not a lot in the way of answers.
Buettner's story has all those elements, but it also proposes some ideas that were, for me, really thought provoking. After spending much of the article discussing the Ikarian's diet (it's low in meat and sugar, high in antioxidants, and includes lots of locally produced food and wine) and their laid-back, low-stress way of life, Buettner doesn't suggest that we'll all live to be 100 if we just, individually, try to live exactly like the Ikarians do. In fact, he points out that other communities of long-lived individuals actually live differently — Californian Seventh-Day Adventists, for instance, eat no meat at all and don't drink, and they live with the normal stresses of everyday American life. Read the rest
The Curiosity rover can do a lot of things, but nobody is expecting her to find direct evidence of life on Mars. In fact, the hunt for life on the Red Planet has been a pretty stunted one. The last time we really looked was during the Viking missions, which tried to find chemical "footprints" that would exist if there had once been life on Mars, but that could end up on that planet for other reasons, as well. What we got back was a less-than-enthralling "Outlook Hazy. Try Again Later."
Ever since, we've contented ourselves with searching for indirect evidence — assessing the planet for signs that it might once have had the conditions necessary for life to happen. That's important, and it will make direct evidence of life more believable if we ever do find it, but it's not quite the same thing.
But now, DNA sequencing tools have become portable enough (and drilling technology has become powerful enough) that some scientists and Craig Ventner think we could send a probe to Mars which could find buried traces of actual DNA protected in the dirt and sequence that DNA on site.
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It's also possible that life hitched a ride between Earth and Mars in their early days. Asteroid impacts have sent about a billion tonnes of rock careering between the two planets, potentially carrying DNA or its building blocks. That could mean that any genetic material on Mars is similar enough to DNA that we have a chance of finding it using standard tests.
Remember arsenic life? In 2010 NASA researchers thought they'd found evidence that certain bacteria could use arsenic in their DNA where all other forms of life on Earth use phosphate. Then it turned out their research was really flawed. Then it turned out they were wrong. In general, there was a to-do.
Fast forward to this month, when scientists from the Weizmann Institute of Science in Rehovot, Israel published a study in which they were trying to figure out how bacteria can tell the difference between phosphate and arsenate and "know" to prefer the phosphate. They used phosphate-collecting proteins from four different species of bacteria in their research, including the one that had been at the center of the arsenic life controversy. And along the way, they discovered a fun twist to that story. Read the rest
When I was about 10, I developed an obsessive love for The X-Men. It started with the Saturday morning cartoon show, but quickly became about comic books, as well. To this day, long-overwritten plot points from the Marvel universe take up a significant portion of my memory space (as my husband can attest). In my marriage, I am the one who is called upon to flesh out the backstory and conflicts with source material after my husband and I have seen an action-hero movie.
But I didn't own a single comic book until I was 19.
In fact, I'm not sure my parents or friends even knew I liked comic books. All my reading, for nine years, was done in secret. I'd slip into the comic book aisle at the bookstore when nobody was around to see, grab an anthology off the shelf, and spend the next two hours nestled in a corner somewhere — with the comics safely hidden behind a magazine or large book. I did the same thing at the public library. Never even checked one out. If I couldn't finish a library comic anthology in one afternoon, I'd hide it in a seldom-used section and come back the next day. (My apologies to the librarians of the world for that.)
Partly, that shame and fear came was about being labeled a nerd, in general. But there was, for me, also a pretty heavy gender component. Tall, clumsy, nerdy, ignorant of fashion or makeup, and definitely not "attractive" in the way that sheltered pre-teen and teenage society defines it, I spent a good chunk of my adolescence paranoid about my identity as a female. Read the rest
A couple of days ago, Rob told you about scientists who had built a "jellyfish" in the lab, using rat cells. Which is awesome. Naturally, it's not quite as awesome as it sounds, though.
The scientists haven't created life. Instead, they've built a little construct of cells and silicone. This construct—the medusoid—is interesting, in that, when you spark it with electricity, it moves in ways that are very similar to a juvenile jellyfish. But it's not actually an animal. It doesn't eat. It can't make more of itself. It needs that outside zap to move at all.
But despite all that it is not, the medusoid is a very cool first step towards doing some amazing things. At Scientific American, journalist Ferris Jabr looked at what the scientists have done, how living jellyfish work, and what it would take to build a for-real-real artificial jellyfish.
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Whereas a real jellyfish generates electrical impulses to stimulate its muscle cells, a medusoid is entirely dependent on voltage generated by electrodes in its tank. Moon jellies have eight pacemaker cells scattered around the middle of their bodies (just about every jellyfish body part comes in multiples of four). Pacemaker cells keep the jellies’ muscles pulsating rhythmically. We have pacemaker cells in our hearts that do the same thing. So do rats. Janna Nawroth thinks it’s possible to weave pacemaker cells from a rat’s heart into the heart muscle tissue that makes up a medusoid, which might allow the artificial jellyfish to bob on its own, sans electrodes.
The Life's Little Mysteries blog is in the midst of a string of posts that are, basically, like Marvel Comics "What If?" series as applied to the scientific history of Earth.
For example: What if humans had evolved to include more than two sexes, or to need three or more sex cells in order to procreate? What if Pangea (everybody's favorite supercontinent) had never split into chunks? What if Earth had never been in a massive collision with another, huge space object—meaning, what if the Moon didn't exist?
Now, if you've read very many of the comics you know that the answer to "What If?" is almost always "everybody dies". This series of posts is a bit less fatalistic. But, still, the point is made—these changes would radically alter life as we know it, and not necessarily in ways that sound like a lot of fun.
Take that question about the Moon. The implications of a Moon-less Earth are farther-reaching than you might guess:
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Huge tides generated by the moon – which orbited much closer to Earth when it formed – washed the chemical building blocks for life from land into the oceans and helped "stir up the primordial soup," said Neil Comins, a professor of physics at the University of Maine.
The moon's gravity has helped slow Earth's rotation from an initial six-hour day to our current 24-hour day, while also stabilizing the tilt of our planet's axis, and thereby moderating the seasons. Life forms on a moonless Earth would therefore have different patterns of activity per the short days and nights, Comins told Life's Little Mysteries.