Twisted Sister: Twin Planets Earth and Venus Were "Separated at Birth"

Twisted Sister: Twin Planets Earth and Venus Were "Separated at Birth"

But they're definitely not identical; Venus today might portend an Earth ravaged by climate change 

  
SOUTH SIDE: Venus's southern hemisphere, shown here in ultraviolet.

Venus is similar in size and chemical makeup when compared with Earth—and the pair formed about the same time, more than four billion years ago. But that is apparently where the similarities end. According to a year's worth of data sent back from the European Space Agency's Venus Express orbiter launched in November 2005, the second planet from the sun is nothing like Earth—from its torrid surface to the upper reaches of its acid-laced atmosphere. The bottom line: just be glad you live here.

Here's some reasons why: Venus's surface temperature hovers around a sweltering 870 degrees Fahrenheit (465 degrees Celsius), its surface pressure is about 90 times that of Earth (which is akin to the pressure a kilometer, or 0.6 mile, below the ocean's surface), and there are no seasons there. The planet—Earth's closest neighbor—takes 243 days to turn on its own axis (and in the opposite direction) compared with Earth's swift 24-hour turnaround time. From the new data, scientists now know its atmosphere consists mostly of carbon dioxide, providing a glimpse of what global warming run amok may yield. Because of the extreme heat, water is only present in its atmosphere, so there are no oceans (and thus, no beaches). There are gale-force winds whipping about the planet, its smoglike clouds are composed of droplets of sulfuric acid (rather than water) and, contrary to previous belief, there is lightning on Venus. In other words, not only is it hot enough to evaporate an igloo on Venus in milliseconds, but you could also get struck by a bolt from the not-so-blue skies.

"Venus and Earth, they're really twins that were just separated at birth," Dimitry Titov, a researcher at the Max Planck Institute for Solar System Research in Katlenburg–Lindau, Germany, and co-author of several of nine papers in Nature on Venus Express's findings, said in a teleconference yesterday. "The key question is why those twins are so different."

An international team of scientists have been pouring over data streaming back from the Venus Express since April 2006 when it began surveying Venus, which at its minimum distance is around 25 million miles (40 million kilometers) from Earth.

At the planet's equator is a layer of turbulent air flow, which smoothes out at higher latitudes, notes Fred Taylor, a University of Oxford physicist and interdisciplinary scientist for the Venus Express mission. The wind speeds in the upper atmosphere are much faster than on Earth, partially due to the Venus's sluggish rotation. There is also evidence of vortexlike swirls of air that are thousands of miles wide at both of its poles, similar to those that appear over Earth's poles during their respective winter months.

Solar winds (gusts of ions from the sun's outer atmosphere capable of pulling apart molecules they encounter) suck up particles in Venus's atmosphere, untangle their atoms and spit them into space. Particulate matter in Earth's atmosphere is largely spared from the solar winds by our planet's strong magnetic field, something Venus lacks. As expected, scientists observed light, charged particles like hydrogen and helium ions leaving Venus's atmosphere. But they were surprised to discover that oxygen is also exiting. Researchers believe that water is being lost from the planet, because twice as many hydrogen as oxygen particles are leaving.

"Venus is very, very dry," says David Grinspoon, an astrobiologist at the Denver Museum of Nature & Science. All the water contained in its atmosphere, he adds, would be about slightly more than one inch (2.5 centimeters) deep if it were on the planet's surface. Analysis of the water leaving Venus's atmosphere, however, shows that many of the hydrogen ions are actually a stable isotope of the element called deuterium, which consists of a proton and a neutron (rather than just a proton) in its nucleus. "The amount of deuterium is an important clue to how much water has been lost over time," Grinspoon says. Researchers estimate that Venus has lost at least an ocean's worth of water since it formed, based on the deuterium particles being swept up by the solar wind.

"These differences are not just [due] to Venus being closer to the sun," Oxford's Taylor says. "We now know that the lack of a protective magnetic field and the differing planetary rotation rates also play a role in ensuring that many of the atmospheric processes we observe on Earth occur at a much faster rate on Venus. Our new data make it possible to construct a scenario in which Venus started out like the earth [did]—possibly including a habitable environment, billions of years ago—and then evolved to the state we see now."

 
VORTEX AHEAD: Venus Express captures a shot of the vortex at the planet's south pole.


 
NOW IN 3D: The south polar vortex in 3-D as seen by the VIRTIS instrument on board ESA's Venus Express.

Venus has frequent bursts of lightning

Venus has frequent bursts of lightning

Nearby Venus is looking a bit more Earth-like with frequent bursts of lightning confirmed by a new European space probe.

For nearly three decades, astronomers have said Venus probably had lightning — ever since a 1978 NASA probe showed signs of electrical activity in its atmosphere. But experts weren't sure because of signal interference.

Now a magnetic antenna on the European Space Agency's Venus Express probe proved that the lightning was real.

"We consider this to be the first definitive evidence of abundant lighting on Venus," David Grinspoon of the Denver Museum of Nature and Science told reporters Wednesday at a briefing in Paris.

The finding is significant because lightning affects atmospheric chemistry, so scientists will have to take it into account as they try to understand the atmosphere and climate of Venus, he said.

The lightning is cloud-to-cloud and about 35 miles above the surface, said University of California, Los Angeles geophysics professor C.T. Russell, lead author of a paper on the Venusian fireworks. It is being published in Thursday's issue of the journal Nature.

Bursts of electrical energy from lightning are something that scientists have long theorized could provide the spark of life in primordial ooze.

But not on Venus.

"If life was ever something serious to talk about on Venus, it would be early in its history, not in its current state," said Sean Solomon of the Carnegie Institution of Washington, who was not part of the research team. "It's a very unforgiving atmosphere."

The idea of Earth-like lightning is fascinating, Russell said. However, you couldn't see it from Venus' surface, nor would you want to look because the Venusian atmosphere is 100 times more dense than Earth's, is about 900 degrees hotter and has clouds of sulfuric acid, he said.

"It may be Earth's 'evil twin,' but it is in many respects Earth's twin," Russell said.

What excites astronomers most about the lightning discovery is simply the coolness factor.

Venus' weather forecasts have long thought to be "kind of boring ... steady winds for the next 400 years," said Allan Treiman, a senior scientist at the Lunar and Planetary Institute in Houston, who isn't affiliated with the research. The idea of lightning, he said, adds a spark to Venus' weather.


An artist's rendition released by the European Space Agency on Wednesday, Nov. 28, 2007 shows lightning striking the surface of planet Venus. Nearby planet Venus is looking a bit more Earth-like with frequent bursts of lightning

Success Depends on Others Failing

Success Depends on Others Failing

 

Reward mechanisms in the brain depend on how well you think other people are doing, a new neurological study suggests. The findings, published in the Nov. 23 issue of the journal Science are the first to lend physiological proof to a longstanding theory among contemporary economists: that people are affected not only by their own achievements and income, but also by how they stack up against their neighbors. 

The researchers were especially interested in the set of outcomes where both players answered correctly. For any given prize value, the brain's reward response was bigger if the other player earned less. Players on average were more pleased with a 60 euro prize when the other player got just 30 euros, for example, than they were if both players earned 60 euros, or if the other player got more.

"In a sense it goes back to Aristotle," says the paper's senior author, Armin Falk, an economist. "The fact that we are social beings is a well-known fact." But the idea that rewards are context-dependent challenges a key assumption behind most traditional of economic theories: the premise that humans are essentially self-interested, that they care about their own work, income, achievements, and purchases, and that whatever other people do is, if not irrelevant, at least not going to have a consistent or predictable effect on decision-making.

Instead, the brain scans from this study support a mountain of survey data collected by modern economists and psychologists that suggests people care very much about keeping up with the Joneses. In the past, researchers have often struggled to work out how much they could trust that data, not sure whether survey-takers might be changing their response consciously or unconsciously based on what they thought was socially acceptable. The Science findings give further empirical evidence that people compare their gains to others'. "If you look at the brain reaction, it's a relatively immediate physiological reaction," says Falk. "It shows on a deeper level, in the brain, these things really matter."

The practical implications? Many scholars believe that social comparison helps to explain why, even as much of the world gets ever richer, people today don't report being happier than people did 50 years ago. We might not be happy now if we had to give up the amenities of the last half-century computers, air conditioners, a bedroom for every child, and more — but back when no one else had them either, life was okay.

There's also a lesson here for company managers, says Falk. A wage scale should reflect job and performance differences fairly, or else firms risk alienating their staff. "It's extremely important for companies to understand it's not just a matter of justice, but it's also a matter of efficiency," he says. It turns out the negative response to earning less is usually stronger than the positive response to earning more or as Falk says, "The pain of having less is much stronger than the joy of having more." Workers who discover they're earning more for the same work may be happy, but those who earn less can quickly feel slighted, killing motivation and often the quality of their output. It doesn't take a brain specialist to understand how that affects a business. 

Evolutionary 'Big Bang' Created Florist's Paradise

Evolutionary 'Big Bang' Created Florist's Paradise

From the ubiquitous daisy to the fantastical orchid, flowering plant species are as diverse as they are numerous. Turns out, these bloomers went through an evolutionary "Big Bang" of sorts some 130 million years ago, a brief era of explosive floral diversification at a time when dinosaurs walked the Earth.

The origin of flowering plants called angiosperms has long baffled scientists, with Charles Darwin famously referring to the plant puzzler as an "abominable mystery."

"One of the reasons why it's been hard to understand evolutionary relationships among the major groups of flowering plants is because they diversified over such a short time frame," said researcher Robert Jansen, professor of integrative biology at the University of Texas at Austin.

Two papers published online this week in the Proceedings of the National Academy of Sciences, reveal the evolutionary relationships between major groups of plant species. The results show a stunning diversification occurred within a period of 5 million years just after the plants first appeared on the scene and gave rise to today's five major lineages of flowering plants. 

"Flowering plants today comprise around 400,000 species," said Pam Soltis, curator at the University of Florida's Florida Museum of Natural History. "To think that the burst that gave rise to almost all of these plants occurred in less than 5 million years is pretty amazing—especially when you consider that flowering plants as a group have been around for at least 130 million years."

Pam and UF colleague Doug Soltis analyzed 61 genes from 45 plant species, while another team led by Jansen analyzed 81 genes from 64 plant species. Both groups focused on the genomes of the chloroplast, an organelle shared by all green plants that is responsible for their ability to photosynthesize.

Then, they arranged the gene sequences into diagrams to reflect the relationships among plant lineages throughout evolutionary history. From the length of the diagrams' branches along with known rates of genetic change, the teams estimated that three lineages went through a major diversification in an evolutionary "blink of an eye."

As for the cause of the explosion of plant diversity, that's still a floral mystery. Perhaps a major climatic event was the trigger, the researchers suggest. Another idea is that a new evolutionary trait, such as the development of a plant's water-conducting tube, jumpstarted the diversification. 

 
Phylogenetic relationships among the major lineages of flowering plants. Pictured counter-clockwise from the root at the base of the circle tree are: Amborella trichopoda, Nymphaea odorata, Illicium floridanum, Chloranthus angustifolius, Piper longum, Liriodendron tulipifera, Ceratophyllum demersum, Ranunculus ficaria, Pelargonium exstipulatum, Helianthus annuus, Yucca filamentosa, Triticum aestivum, and Acorus americanus. New Caledonia, home to Amborella trichopoda, is shown in the background. 

 
Two new studies reveal an explosion of plant diversity occurred in a stint of 5 million years just after flowering plants first appeared on Earth, giving rise to today's five major lineages, including plants such as orchids. 

A Video That's Worth a Million Words

A Video That's Worth a Million Words

Award-winning video reveals the simplicity and beauty of an abstract mathematical tool

Abstraction lies at the heart of mathematics. It makes math powerful, but at the same time, it can make math hard to understand. Abstraction makes math simultaneously beautiful and austere, useful and esoteric.

But a picture can tame the mad monster of abstraction, and sometimes, a video can do so even better. Now, a pair of mathematicians has created a video (see http://www.youtube.com/watch?v=JX3VmDgiFnY) that shows how to visualize and understand Möbius transformations, which are a fundamental and highly abstract mathematical tool. The new video, "Möbius Transformations Revealed," has become an Internet sensation, with 60,000 hits on YouTube so far. It also won honorable mention in the Science 2007 Science and Engineering Visualization challenge.

A Möbius transformation begins with a plane and moves each point to a new location according to certain rules. In their video, Douglas N. Arnold and Jonathan Rogness of the University of Minnesota in Minneapolis transform a multicolored square into new shapes using Möbius transformations.  

A Möbius transformation can turn the square on the left into the bizarre form on the right. Click here or on the image to see a video that shows how the transformation works.

A Möbius transformation alters an entire plane. To understand the transformation, it helps to focus on a square that lies on the plane. A Möbius transformation can alter the square in any of four ways. The first three ways aren't too hard to picture: the transformation can move a square around on the plane, expand or contract the square, or rotate it.

The fourth alteration is especially intriguing. A Möbius transformation can turn the square inside out. The Arnold-Rogness video illustrates this process beautifully, showing how points that start close to the square's center are sent far outward, while points near the edge of the square move toward the center.  

When a square is turned inside out through a Möbius transformation, it takes on this flower-like shape.

 Next comes the video's magical step. The mathematicians move into the third dimension to provide a way of visualizing the Möbius transformations. They suspend a sphere above the plane and use it a bit like a slide projector. They put a picture onto the sphere, and a light at the top of the sphere shoots an image of the picture down onto the plane. The picture on the sphere is shaped in such a way that when the light projects the image onto the plane, it forms the original square.  

A light at the top of the sphere projects an image of the square down onto the plane.

 Now imagine moving the sphere while continuing to shine the light from its top. The "slide projection system" will change the image on the plane, producing a Möbius transformation of the image. Move the sphere a bit to the left, and the projected square will move the left. Move the sphere up, and the square will expand. Rotate the sphere around its vertical axis, and the square will also rotate.

If you turn the sphere upside down but keep the light in the same spot above the plane, the square will turn inside out! This is the puzzling "inside-out" transformation.  

Moving this sphere around produces a Möbius transformation of the image. Turning the sphere upside down turns the image inside out.

 "You need some pretty heavy mathematical machinery that people usually don't do until their first year of grad school to prove the stuff in the video," Rogness says, "but we've been showing this to high school students and they seem to get it."

Rogness and Arnold had both heard that Möbius transformations could be visualized in this way, but when they began working on the video, they realized that they had never seen a proof that the method works. They hunted through textbooks and could not find a reference to the proof, even though all the mathematicians they talked to knew it to be true. Finally, they sat down and proved it themselves.

"It's a folk theorem," Rogness says. "Everyone seems to know it but I'm still not sure when it was first proven or by whom."

The duo has been astonished by the video's popularity. "I put up the YouTube version just so that we could mention it to friends and fellow mathematicians, expecting a few hundred people might watch it," Rogness says. After the video was mentioned on the technology website Slashdot, about 20,000 people viewed it overnight, and the numbers have continued to increase ever since, Rogness says with amazement. "It's been many orders of magnitude more than I expected."