Group items tagged

The Earth is a ball that floats in space, and the Earth’s surface—the tectonic plates that make up the land—are like a shell that floats on the mantle below. Just like the hard chocolate coating can slip and slide on your soft serve ice cream, the crust of the Earth can slide over the mantle. This is different than continental drift. This is the whole surface of the planet moving as one. The rotation axis of the Earth stays steady, the land masses shift around it. The idea is known as “true polar wander,” and its occurrence is a part of the planet’s history.

Typically, we do not pay much attention to the delineation of the sea because it seems so obvious and constant that we do not realize it is a foundation of geography and the basis for our perception of the physical world.

Sea level is—and has always been—in equilibrium with the planet's gravity, which pulls the water toward the earth's center of mass, and the outward centrifugal force, which results from the earth's rotation. After a few billion years of spinning, the earth has taken on the shape of an ellipsoid (which can be thought of as a flattened sphere). Consequently, the distance to the earth's center of mass is the longest around the equator and shortest beyond the polar circles.

Throughout most of the 545 million years during which there has been visible life on Earth (the Phanerozoic Eon), Greater India was not part of Asia, and it was not a peninsula.

Throughout most of the 545 million years during which there has been visible life on Earth (the Phanerozoic Eon), Greater India was not part of Asia, and it was not a peninsula.

Throughout most of the 545 million years during which there has been visible life on Earth (the Phanerozoic Eon), Greater India was not part of Asia, and it was not a peninsula.

The Earth is built to last. It is a 4,550,000,000-year-old, 5,973,600,000,000,000,000,000-tonne ball of iron. It has taken more devastating asteroid hits in its lifetime than you've had hot dinners, and lo, it still orbits merrily. So my first piece of advice to you, dear would-be Earth-destroyer, is: do NOT think this will be easy.

I will define our goal thus: by any means necessary, to change the Earth into something other than a planet or a dwarf planet.

The question of habitability is a second-order consideration when it comes to Gliese 581g, and that fact in itself reveals where so much of this uncertainty comes from. As of right now, the most interesting thing about the "discovery" of Gliese 581g is that not everyone is convinced the planet actually exists. That's basically because this particular detection is very much indirect - the planet's existence is being inferred from periodic meter-per-second shifts in the position of its host star.

So it's very difficult to just detect these things, and actually determining whether they are much like Earth is a task orders of magnitude more difficult still. Notice how I'm being anthropocentric here: "much like Earth." Astrobiology has been derisively called a science without a subject. But, of course, it does have at least one subject: our own living planet and its containing solar system.

This is really a chicken-and-egg problem: To know the limits of life in planetary systems, we need to find life beyond the Earth. To find life beyond Earth, it would be very helpful to know the limits of life in planetary systems. Several independent groups are trying to circumvent this problem by studying abiogenesis in the lab - trying to in effect create life, alien or otherwise, in a test tube.

Going across the Atlantic would be out of the way and make the trip longer. Here is the shortest path from Dubai to Los Angeles:

This "Mercator projection" is extremely stretched out near the poles, so a path that goes through very high latitudes is stretched out quite a lot on the map. It looks much longer than it really is. Thus, although the path straight across the Atlantic looks shorter, it is actually longer.

Mathematically, this impossibility of a perfect map projection means the metric for the Earth is different from that of a map. It results from the Earth being curved in a technical sense.

Among paleontologists, it's sometimes called the "Great Dying." Roughly a quarter of a billion years ago, 90-95 percent of all life on Earth died out. It took 30 million years for the planet to recover. What happened?

The era before the Great Dying - also known as the Permo-Triassic Extinction - is called the Permian, and it was a time of rapid animal evolution, including mammal-reptile hybrids called synapsids that looked sort of like giant lizards - some even had big sails on their backs.

there were actually three die-offs during the Permian, but the one at the end of the Permian and the beginning of the Triassic, 250 million years ago, was extreme.

Recent findings—such as that life seems to be everywhere on Earth—have encouraged scientific inquiries into the nature of life’s beginnings, said Szostak.

Two critical needs for life are to create a membrane, which defines a boundary that can contain genetic material, and to replicate. Szostak said it is relatively easy to create a membrane from fatty acids that could have arisen in conditions that mimic early Earth; fatty acids, mixed in water with a little salt, readily create closed structures called vesicles.

The 2009 State of the Climate report released today draws on data for 10 key climate indicators that all point to the same finding: the scientific evidence that our world is warming is unmistakable. More than 300 scientists from 160 research groups in 48 countries contributed to the report, which confirms that the past decade was the warmest on record and that the Earth has been growing warmer over the last 50 years.

That’s not correct. Of course this report is deniable. That’s what deniers do: deny. And we’ll be hearing from them in the comments below, have no doubts.

Mind you, I am distinguishing, as I always do, between deniers and skeptics. Those are two very different things. I am, quite literally, a skeptic of global warming. I do think it’s happening, but that’s because that’s what the evidence is telling me.

The Earth has entered a new geological period in which human influence dominates the state of the planet, compounding uncertainty about the future.

Crutzen and Stoermer made the case that the Holocene, the geological epoch that had held sway on Earth for the past 12,000 years, was at an end. In its place, with a start date pegged to the late 18th century commercialization of James Watt’s steam engine, was the Anthropocene, an epoch defined by the influence of humanity’s collective actions.

For humans, adjustments to a warming world can be divided into three categories: mitigation, adaptation, and remediation.

according to a new book by astrobiologist Dirk Schulze-Makuch and science writer David Darling, we’ve had good evidence of microbial life on Mars since NASA’s Viking missions in the late 1970s.

The Viking researchers thought life on Mars would be heterotrophic, feeding off abundant organic compounds distributed everywhere all over the Martian surface. That picture was wrong, and studies of extremophiles on Earth have made us think differently about Mars.

In order to keep the time determined by Earth's motion in line with the seconds measured by atomic clocks, the International Earth Rotation and Reference Systems Service inserts "leap seconds" into the calendar. But leap seconds may fall out of favor after next year's World Radiocommunication Conference

the National Institute of Standards and Technology (NIST) uses the resonant frequency of cesium-133 atoms in the NIST-F1 Cesium Fountain Atomic Clock to keep time so accurately that even if it ran for 60 million years, NIST-F1 wouldn't drop or add a single second.

atomic clocks are actually more stable than Earth's orbit—to keep clocks here synched up with the motion of celestial bodies, timekeepers have to add leap seconds.

I describe this global system of technology deployed around the planet as an emerging superorganism. It consists of roads, electric lines, telephone cables, buildings, water systems, dams, satellites, ocean buoys and ships, all our computers and data centers, and all 6 billion humans. But while this superorganism of new and old technology operates at the planetary scale, and reaches all continents, and spans the oceans, and reaches into orbital space, it is a thin and uneven layer on the globe. In fact most of the planet, on average, is in a very primitive state.

Let's draw a grid around the globe with lines that form a square approximately every 100 km (at the equator). At every intersection of these grid lines we'll take a picture for inspection. There are about 10,000 intersections over the land part of this planet. They will give us a very good statistical portrait of what this planet looks like on land. Shown are 6,000 images of a possible 10,000 degree intersections on land.

The imaginary grid is the longitude and latitude grid, and somewhat remarkably, over 6,000 of the 10,000 intersections have already been photographed. Intrepid volunteers sign up at a web site called the Degree Confluence that is half art-project, and half adventure storytelling in order to select an intersection somewhere on the globe to visit --no matter how wild -- and record their success with photographs including a legible snapshot of their gps proving a bonafide "even" lat-long reading with lots of zeros.

How prosaic business opportunities generate the most risky and grandiose undertakings has come to interest me. This school arose with the specific goal of training sailors to go farther and farther south along the African coast in search of a sea route to India.

The Portuguese sought this route to cut out the middleman in the spice trade. Spices were wealth in Europe; they preserved and seasoned food, and were considered medicinal and even aphrodisiacs. But they were fiendishly expensive

The more I learn more about Henry, the more his program reminds me of NASA and of Tom Wolfe's classic, The Right Stuff, about America's space program. Like NASA, each mission built on the last, trying out new methods in an incremental fashion. Henry didn't try to shoot to the moon, as they say. He was no Columbus, risking everything for glory, but rather a methodical engineer, pushing the limits a little at a time and collecting data.

These guys argue that it’s possible to measure the complexity of life and the rate at which it has increased from prokaryotes to eukaryotes to more complex creatures such as worms, fish and finally mammals. That produces a clear exponential increase identical to that behind Moore’s Law although in this case the doubling time is 376 million years rather than two years.That raises an interesting question. What happens if you extrapolate backwards to the point of no complexity–the origin of life?Sharov and Gordon say that the evidence by this measure is clear. “Linear regression of genetic complexity (on a log scale) extrapolated back to just one base pair suggests the time of the origin of life = 9.7 ± 2.5 billion years ago,” they say. And since the Earth is only 4.5 billion years old, that raises a whole series of other questions. Not least of these is how and where did life begin.

For example, is it reasonable to think that the complexity of life has increased at the same rate throughout Earth’s history?

Illusionists Penn and Teller barely communicate outside work – but after 35 years together they still create the most beautiful shows on earth. Ahead of their first British performances for 16 years, Benjamin Secher went to Las Vegas to ask them how they do it .

Penn dominates the stage, pointing, spouting like an evangelist, encouraging us to see the big ideas behind the wizardry, plucking at his double bass, doing dangerous looking things with a nailgun, cracking jokes at the expense of Homeland Security or dispensing a running commentary on Teller’s sleights of hand. He also has a habit of giving away the tricks – before Teller’s red ball act, he declares “this is done with a thread!” – something he describes as “a kind of peace offering” to the audience but which some of the other magicians in Vegas see as a professional blasphemy. He couldn’t care less what they think. “I have always hated magic,” he says. “I have always hated the basic undercurrent of magic which Jerry Seinfeld put best when he said: 'All magic is “Here’s a quarter, now it’s gone. You’re a jerk. Now it’s back. You’re an idiot. Show’s over”.’ I never wanted to grow up to be a magician. It was never my goal.” He would rather have been a rock star, he says, but the business seemed already saturated with extraordinarily talented people. “So my thinking was, and I will say this outright, music is full of people I absolutely love. I don’t have a chance. They are all better than me. Magic has, ooh, nobody in it that I like.” He rocks back in his chair, cackling. “This is the field for me!”

Germany is, of course, not like any other country. It was the primary culprit behind the deadliest conflict to ever befall mankind — World War II — and of the greatest state-organized massacre of a single group of people — the Jewish Holocaust. As such, it essentially was forced to give up much of its sovereignty for the next 40 years and to serve as the board for the geopolitical chess match between Washington and Moscow throughout the Cold War.

Germany is forcefully defending its interests and national economic strategy ahead of the G-20 summit. The stage is therefore set for a serious disagreement between Washington and the chief trade surplus countries, specifically Germany and China, at the summit. Germany is also beginning to take shots at China, especially for its decision to limit exports of rare earth elements crucial for German industry. These economic disagreements come as Berlin becomes comfortable with its own geopolitical assertiveness. As far as Germany is concerned, it is no longer anybody’s chessboard. It is beginning to see itself as one of the world powers again — with grand strategies, pawns to sacrifice and everything else that goes along with the title of a chess grand master.

Forget banking and the automotive industry. Earth is the one system that is truly “too big to fail.”

Those fixes could slow environmental degradation but might not solve the underlying cause. That culprit, according to Middlebury College scholar in residence Bill McKibben, is the very driver of modern society: a relentless quest for economic growth. In an exclusive excerpt from his upcoming book, McKibben argues that we must give up growth and reorganize based on smart maintenance of resources. Critics say the idea is unrealistic; staff editor Mark Fischetti challenges him to respond. 

The modern concept of Geoengineering (or Climate Engineering) is usually taken to mean proposals to deliberately manipulate the Earth's climate to counteract the effects of global warming from greenhouse gas emissions.