Bonnie Dunbar on the end of the space shuttle era
Final space shuttle launch July 8, 2011
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After 30 years and 135 missions sent to Earth orbit, the U.S. space agency NASA ended the space shuttle era with the final landing of shuttle Atlantis on July 21, 2011 at 5:56 a.m. EDT. EarthSky’s Jorge Salazar spoke with astronaut and engineer Dr. Bonnie Dunbar, who made five shuttle flights and helped build NASA’s shuttle program in the 1970s.
What are your thoughts on the final flight of space shuttle Atlantis and of NASA’s shuttle program?
I’m very proud of that program, having been associated with the original development of it in the 1960s, and 30 years of flight experience, having flown five flights myself, and having been an engineer on the shuttle for Rockwell when we built it in the 1970s. I have to tell you, it’s an amazing vehicle. It hasn’t been replicated yet. And I’m sorry to see it stop flying.
Final Space Shuttle launch July 8, 2011
Looking forward, what would you like to tell people who feel that gap in hopes and dreams of spaceflight with the end of the shuttle program?
First of all, I’ve heard the comment, why doesn’t NASA do this, or do that. I think this is a civics lesson. NASA works through the President, and it implements programs decided by the nation. It doesn’t decide on its own. It can propose science. It can propose destinations. But the funding for that, the final decision comes through a collaboration between Congress and the administration.
What we do is very dependent upon what the American public wants to do. It doesn’t happen in a vacuum. So if the American public wants this nation to continue to lead in space, or be one of the leaders, to innovate and pump resources into new technologies and new knowledge, they have to articulate that.
There’s a misconception on how much of our resources go into space. When we were going to the moon, we peaked at about 4.4 percent of our federal budget. And out of that, we got satellites, weather tracking, communications, computers, new materials, new medical technologies ad infinitum. I think the studies show about a ten to one on return on investment. The present cost of our human spaceflight program is less than one-half of one percent. This nation spends more on cosmetics and I think potato chips and pizza than it does on investments in technology and explorations.
I think it’s really important to have an open debate about what we want to be in the 21st century as a nation. My hope is that we continue to lead. Great nations explore. In the process of exploration, they acquire new knowledge and they generate new technologies that go into their well being and their standard of living. And if we pull back now, I think that we should look at the lessons of history. We may not be happy with the results.
As a scientist, what would you say is the most significant contribution to science made by space shuttle Atlantis?
That’s an interesting question. I’d have to back through the manifest.
As a scientist and engineer – having built the shuttle – a huge contribution was just the accomplishment of what we did. We put a lifting body into space, launched it like a rocket, landed it like an airplane. We were to take 50,000 pounds, not just to Earth orbit but bring it back. We sustained up to eight people in space – there were eight crew members on my first flight – that’s engineering achievement.
So just the building and successful operating of the shuttle has advanced us decades in learning how to live and operate in space.
The space shuttle is a platform, and it’s a cargo truck – all those things. Taking objects to orbit, bringing them back, carrying space labs in them so that we can do research in microgravity environments, both biomedical and materials science. Those are small stepping stones, but unless we do those things, we’re not going to continue to explore. You need all of that core technology before you can really explore.
What’s the legacy of the space shuttle program?
I think in the next 50 years, we’re going to be taking a lot of people to space, like Boeing aircraft, Airbus aircraft take people into the air. You’ve got to look at more capacity. And I think that more capacity takes you to winged vehicles. You just can’t do it in capsules. And so what we might see in the future is a look-back at what we did on the shuttle, to be able to carry so much cargo and people into Earth orbit.
Bonnie J. Dunbar
You’ve flown five missions on four different space shuttles. What do you remember most about the shuttle era?
That’s a hard one to answer. I was just very fortunate to be part of some of the initial R&D, while I was an undergraduate at the University of Washington, in Seattle. This was in the 1960s, when NASA was already working with the universities on selection of materials for the thermal protection system. Then I was very fortunate in the 1970s to go to work for Rockwell, helping to build Columbia. And then to be selected as a flight controller in 1978, as a payload officer. And then in 1980, as an astronaut, then flying the five flights.
So I’ve had an opportunity to look at the engineering, the operations, and the flight part of working on the shuttle. And it’s such a complex but beautiful vehicle that has worked so well. We’re on our 135th flight. Who would have known?
People look back at history and say, maybe it should have been 150. That’s not the point. The point is this is hard to do. The Soviet Union tried to do it with Buran, and they weren’t able to. We should be proud of what the engineering community was able to achieve and know that it’s going to be a platform for the future.
What’s the most important thing you want people today to know about NASA’s space shuttle program?
I want them to pay tribute to the great engineers, both at NASA and with the contractors – this is a real team effort across the nation – to really thank them for what they did back in the 1960s and the 1970s when they built this amazing vehicle that has taken twice as many astronauts into space as any other country has, and has flown international astronauts, gave us the Hubble Space Telescope, helped to assemble the International Space Station, and has probably given thousands of graduate students their dissertations based on the research that was done, and published papers.
I personally thank all of them, and I hope the American public will as well
Researchers devise more accurate method for predicting hurricane activity
A new method for forecasting seasonal hurricane activity developed by North Carolina State University researchers is 15 percent more accurate than previous techniques.
“This approach should give policymakers more reliable information than current state-of-the-art methods,” says Dr. Nagiza Samatova, an associate professor of computer science at NC State and co-author of a paper describing the work. “This will hopefully give them more confidence in planning for the hurricane season.”
This visible image of Tropical Storm Leslie and Hurricane Michael was taken by the MODIS instrument aboard both NASA’s Aqua and Terra satellites. Image Credit: NASA Goddard/MODIS Rapid Response Team.
Conventional models used to predict seasonal hurricane activity rely on classical statistical methods using historical data. Hurricane predictions are challenging, in part, because there are an enormous number of variables in play – such as temperature and humidity – which need to be entered for different places and different times. This means there are hundreds of thousands of factors to be considered.
The trick is in determining which variables at which times in which places are most significant. This challenge is exacerbated by the fact that we only have approximately 60 years of historical data to plug into the models.
The researchers, including Dr. Fredrick Semazzi (pictured), hope to use their new method to improve our understanding of hurricane behavior. Image Credit: Roger Winstead.
But now researchers have developed a “network motif-based model” that evaluates historical data for all of the variables in all of the places at all of the times in order to identify those combinations of factors that are most predictive of seasonal hurricane activity. For example, some combinations of factors may correlate only to low activity, while other may correlate only to high activity.
The groups of important factors identified by the network motif-based model are then plugged into a program to create an ensemble of statistical models that present the hurricane activity for the forthcoming season on a probability scale. For example, it might say there is an 80 percent probability of high activity, a 15 percent probability of normal activity and a 5 percent probability of low activity.
Definitions of these activity levels vary from region to region. In the North Atlantic, which covers the east coast of the United States, high activity is defined as eight or more hurricanes during hurricane season, while normal activity is defined as five to seven hurricanes, and low activity is four or fewer.
Using cross validation – plugging in partial historical data and comparing the new method’s results to subsequent historical events – the researchers found the new method has an 80 percent accuracy rate of predicting the level of hurricane activity. This compares to a 65 percent accuracy rate for traditional predictive methods.
In addition, using the network model, researchers have not only confirmed previously identified predictive groups of factors, but identified a number of new predictive groups.
The researchers plan to use the newly identified groups of relevant factors to advance our understanding of the mechanisms that influence hurricane variability and behavior. This could ultimately improve our ability to predict the track of hurricanes, their severity and how global climate change may affect hurricane activity well into the future.
Brightest biological substance reveals its secret
Pollia condensata: brightest biological substance
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Most colors in nature are produced by pigments, which are chemicals that selectively absorb and reflect different wavelengths of light. Most paints, for example, are a blend of several pigments, intended to reflect light in such a way that you see a specific color. But yesterday (September 10, 2012), scientists publishing in the Proceedings of the National Academy of Sciences said that the “brightest biological substance” in nature – a spectacular African fruit that is intensely colored blue – creates its own color not from a pigment, but from specialized structures in its cells.
Some pigments fade over time. But, even when it dies – although its leaves turn dry and brown – the fruit of Pollia condensata continues to shine for years with an iridescent hue. That’s becaues its color comes not from a pigment, but from specialized cells within the fruit. Image Credit: P.J. Rudall.
This African fruit is called Pollia condensata – sometimes called the marble berry. It’s found growing wild the forests of Ethiopia, Mozambique, Tanzania and other African countries. It has shiny blue berries – said to be hard as a rock – that are mainly seeds. Although it’s called a fruit, it can’t be eaten. In some African nations, the small metallic fruits have been used for decorative purposes because their colors stay intense for many years.
This African fruit is hard as a rock. It can’t be eaten, but it’s had a decorative use in the past because its color stays intense for years. Image Credit: P. Moult
Scientists call this plant’s way of producing color structural color. It’s known in animals, for example, the brilliant hued feathers of male peacocks, the carapaces of certain beetles and the wings of some butterflies. These creatures all use different structures and materials to their iridescence. The African plant is the first demonstration of structural color in a fruit.
Scientists have learned that cells in the fruit Pollia condensata have walls made of tightly coiled cellulose strands that are excellent for reflecting light. Image Credit: R. Faden
A specimen of P. condensata at the Kew Botanical Gardens in London – gathered in Ghana in 1974 – maintained its intense color. Researchers from the Kew, the University of Cambridge and the Smithsonian Natural History Museum were intrigued. They wanted to know how this plant keeps its color for so long. What they found is that cells in the fruit of Pollia condensatahave walls made of tightly coiled cellulose strands. Different spacings between the strands in each cell reflect light of different wavelengths, producing the iridescent blue colouring of this plant.
The Pollia condensata fruits reflect more polarized light than any other known living substance.
Bottom line: A plant found throughout Africa – called Pollia condensata, or marble berry – has been found by scientists to be the “brightest biological substance” in nature. Its brightness comes not from a pigment, but from specialized cells within the plant. Scientists call this sort of color structural color. Although some animals, such as peacocks, are known to produce color in this way, this is the first example of structural color within a fruit
Astronomers see explosion in Jupiter’s cloudtops
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Amateur astronomers are reporting a bright spot on the planet Jupiter, apparently an explosion in the planet’s upper atmosphere caused by an incoming piece of space debris that struck yesterday morning – September 10, 2012 at 6:35 a.m. CDT (11:35 UTC). Jupiter is the largest world in our solar system and a gas giant world. What we see of the planet – its red-and-white banded surface – is only the tops of the clouds in its exceedingly dense upper atmosphere. Comets and asteroids have been seen to strike Jupiter’s clouds in the past.
Yesterday’s apparent explosion occurred in the cloud tops of Jupiter’s North Equatorial Belt by American amateur astronomer Dan Petersen of Racine, Wisconsin. He was using a 12-inch telescope to observe the planet. He wrote on the Cloudy Nights forum that a “bright white two-second long explosion” happened just inside Jupiter’s eastern limb, or edge.
Amateur astronomer George Hall caught a video of the explosion in Jupiter’s cloudtops. To see it, click here
Another amateur astronomer, George Hall in Dallas, caught a video of the event. To see it,click here
Astronomers are waiting to see if a dark spot develops inside the southern regions of Jupiter’s North Equatorial Belt over the next day or two. As Dan Peterson said:
My best guess is that it was a small undetected comet that is now history. Hopefully, it will sign its name on Jupiter’s cloud tops.
Similar impacts were observed in June and August 2010. An analysis of those earlier events suggests that Jupiter is frequently struck by asteroids. After all, it orbits the sun just outside the asteroid belt, and its gravity is strong.
Brown spots mark the places where fragments of Comet Shoemaker-Levy 9 tore through Jupiter’s atmosphere in July 1994. Image via Wikimedia Commons
Comets are also seen to strike Jupiter. This apparent impact to Jupiter comes slightly more than 15 years after pieces of Comet Shoemaker-Levy 9 famously hit Jupiter in 1994. That was the first time astronomers had directly observed impacts between two bodies in our solar system – although such impacts were believed to be ubiquitous in the early history of the solar system and although we know they still happen fairly often today.
Since Shoemaker_Levy, amateur astronomers who watch Jupiter continuously with small telescopes have recorded a number of smaller apparent impacts.
In the coming days, astronomers across the globe will be monitoring Jupiter for signs of debris left by the September 10, 2012 impact. Some impacts do produce dark “bruises” on the planet’s clouds, but others don’t. According to the website spacweather.com:
Researchers aren’t sure why; perhaps this event will provide some clues.
Bottom line: On the morning of September 10, 2012, American amateur astronomers who were gazing at Jupiter spied a bright spot that suddenly appeared in the planet’s upper atmosphere. They believe it was a small comet or asteroid striking Jupiter. Astronomers in the coming days will be monitoring the planet for signs of “bruises” left by the impact.
TONIGHT FORSEPTEMBER 11, 2012
Courtesy U.S. Naval Observatory
If you’re up at dawn tomorrow, you’ll easily see the waning crescent moon pairing up with the planet Venus. After all, the moon and Venus rank as the second-brightest and third-brightest celestial bodies, respectively, after the sun. But if you’re up before the onset of dawn, you can also catch the glorious Beehive star cluster in close vicinity to Venus.
In a dark country sky, the Beehive looks like a small smudge of light with the unaided eye. Binoculars, though, reveal that this faint fuzzy is actually a cluster teeming with stars. Venus lodges close to the Beehive for the next several days, making it rather easy to locate this star cluster in the predawn sky. By the way, the Beehive resides very close to the center of the constellation Cancer the Crab.
Two faint yet visible stars flank the Beehive cluster: Asellus Borealis (Northern Donkey) and Asellus Australis (Southern Donkey). According to star lore, creatures such as donkeys were unbeknownst to the giant Titans when the Olympians and Titans were engaging in their legendary struggle. The donkeys’ braying – which the Titans had never heard before – alarmed them so greatly that they readily retreated from the Olympians. In gratitude, Jupiter placed these donkeys in the sky, providing them with a crib of hay forever after.
This larger-than-life tale takes stage within a single binocular field of view, a classic that’s as timeless as the stars! Use the waning crescent moon to find Venus, and this dazzling planet to locate the Beehive cluster during the predawn hours on Wednesday, September 12.
Study shows wine has more cardiovascular benefits than vodka
Red wine proves better than vodka for pigs with high cholesterol, according to a new study.
Rhode Island Hospital researcher Frank Sellke, MD, chief of cardiothoracic surgery at Rhode Island and The Miriam hospitals, and his colleagues studied the effects of red wine and vodka on pigs with high cholesterol and found that the pigs with a penchant for pinot noir fared better than their vodka swilling swine counterparts.
“There has been previous research touting the benefits of moderate consumption of wine, but we wanted to test the effects of both wine and vodka in conjunction with high cholesterol as those who would be in this at-risk patient population typically have other medical issues, such as high cholesterol,” said Sellke, the study’s principal investigator. “What we found is that moderate consumption of both alcohols may reduce cardiovascular risk, but that red wine may offer increased protection due to its antioxidant properties.”
The study involved three groups of swine that had been fed a high fat diet. One group continued on the diet alone, the second was supplemented daily with red wine, and the third was supplemented daily with vodka. The wine and vodka was mixed with the pigs’ food, and the dosages were selected to provide equal amounts of alcohol to both treated groups.
After seven weeks, it was determined that the subjects that had been given wine or vodka had significantly increased blood flow to the heart, with the red wine having the larger cardiovascular benefit. Additionally, it was determined that HDL, or good cholesterol, was significantly increased in the two alcohol-treated groups while total cholesterol levels were unaffected. HDL (good) cholesterol transports LDL (bad) to the liver where it is metabolized, which may assist in preventing hardening of the arteries, or atherosclerosis, and other cardiac issues.
Through this study, researchers determined that while both red wine and vodka can benefit the heart, they do so differently. Red wine dilates blood vessels, while vodka caused more collateral vessels to develop. These finding shed new light on the mechanisms by which moderate alcohol intake might reduce cardiovascular risk. Whether these beneficial effects are also seen in humans remains to be seen.
Previous studies have shown that beer, wine and spirits are associated with reduced cardiovascular risk. In particular, several substances unique to red wine have been investigated for their antioxidant, pro-angiogenic and anti-inflammatory properties. The most well known is resveratrol. However, it’s important to note that even among red wines, there is a large variation in actual resveratrol content. Though Californian pinot noir is reported to have one of the highest resveratrol contents, the amount of resveratrol in the wine chosen for this study was lower than that reported for other red wines.
Listening to astronomy
Image via listverse.com
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Astronomy started out as a purely visual science, but with today’s electronics and techniques, you can also hear astronomy. It used to be that you to take classes, or else had to be in the right place at the right time to hear a lecture on astronomy. But, thanks to the Internet, there are many resources for hearing astronomy online.
Of course, you can hear astronomy information right here on this website, via the 90-secondEarthSky interviews. You can also hear 22 minutes of science and music each week from EarthSky on the EarthSky 22 podcast.
And there is AstronomyCast with Frasier Cain and Pamela Gay.
But what really got me to thinking about this was the Silicon Valley Astronomy Lectures, a series of audio podcasts by eminent astronomers, from the Astronomical Society of the Pacific. Among the lectures are Dr. Jeff Moore (NASA Ames Research Center): “New Horizons at Jupiter (and Some Saturn News)”; Dr. David Morrison (NASA Ames Research Center): “Taking a Hit: Asteroid Impacts and Evolution”; Dr. Dana Backman (SETI Institute and Astronomical Society of the Pacific): “A Ringside Seat to the Formation of Planets”; and Dr. David Grinspoon (Denver Museum of Nature and Science): “Comparing Worlds: Climate Catastrophes in the Solar System”.
You may already be familiar with Science at NASA, and there are also podcasts from the mainNASA site, as well as the Jet Propulsion Laboratory (JPL).
Well, that was just a start. I did a little online searching and was amazed to find all the places you can hear astronomy. You might want to do a little searching for yourself. If the links above don’t give you enough to listen to, here are a few more.
I also found the Astronomy Media Player, which is actually web page with links to a number of astronomy and space podcasts from around the world
Salt seeds clouds in the Amazon Rainforest
The cloud cover, precipitation, water cycle, and even the climate of the Amazon basin can be traced back to salts from fungi and plants in the undisturbed jungle.
It’s morning, deep in the Amazon jungle. In the still air innumerable leaves glisten with moisture, and fog drifts through the trees. As the sun rises, clouds appear and float across the forest canopy … but where do they come from? Water vapor needs soluble particles to condense on. Airborne particles are the seeds of liquid droplets in fog, mist, and clouds.
Water droplets in the morning mists of the Amazon jungle condense around aerosol particles. In turn, the aerosols condense around miniscule salt particles that are emitted by fungi and plants during the night. Image Credit: Fabrice Marr/Creative Commons.
To learn how aerosol particles form in the Amazon, Mary Gilles of the Chemical Sciences Division at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and David Kilcoyne of the Lab’s Advanced Light Source (ALS) worked with Christopher Pöhlker of Germany’s Max Planck Institute for Chemistry (MPIC) as part of an international team of scientists led by MPIC’s Meinrat Andreae and Ulrich Pöschl. They analyzed samples of naturally formed aerosols collected above the forest floor, deep in the rainforest.
Combined with results from other facilities, the ALS analysis provided essential clues to the evolution of fine particles around which Amazon clouds and fog condense, beginning with chemicals produced by living organisms. The team found that among the most important initial triggers of the process are potassium salts.
Dissecting invisible aerosols
At ALS beamline 5.3.3.2, the researchers performed scanning transmission x-ray microscopy (STXM) to determine the near-edge x-ray absorption fine structure (NEXAFS) of particles collected during the wet season in the remote, pristine forest northeast of Manaus, Brazil.
“Through absorption of soft x-rays by an atom’s core electrons, and subsequent emission of photons, the identity and exact location of the elements in the aerosol samples can be identified,” says Kilcoyne. “The essence of STXM is that it not only tells you if carbon is present but how this carbon is bound to other elements within the aerosol particles. This allows us to distinguish between soot, which is graphitic, and organic carbon.”
The researchers found three different types of organic aerosol particles, all similar to laboratory-generated reference samples: oxidation products based on precursor chemicals emitted in the gas phase by trees, including terpenes (the major component of turpentine) from tree resin, and isoprene, another organic compound abundantly released through leaves.
The samples were on the scale of mere millionths or billionths of a meter. The smaller the aerosol, the greater the proportion of potassium – those collected early in the morning were the smallest and richest in potassium. Larger particles contained more organic material but not more potassium. These facts suggest that potassium salts generated during the night acted as seeds for gas-phase products to condense onto, forming aerosols of different kinds.
“Biomass burning is also a rich source for potassium-containing aerosols in forested regions, but potassium from forest fires is correlated with the presence of soot, a graphitic form of carbon,” Gilles says. “Before and during the collection period there were no documented fires that could have affected the biosphere where the samples were collected, and no evidence of soot was observed in the samples. Hence the source of potassium could only have been natural forest organisms.”
Prime suspect
Fungal spores in the larger aerosol samples pointed to the prime suspect. Some fungi launch spores by building up water pressure through osmosis in sacs (asci) that contain the spores; when the pressure is great enough, the ascus bursts and squirts the spores into the air, along with fluid containing potassium, chloride, and sugar alcohol. Other fungi fire “ballistospores” when water vapor in the atmosphere condenses and causes a sudden release of restraining surface tension, also ejecting potassium, sodium, phosphates, sugars, and sugar alcohol.
Other biogenic mechanisms also release salts into the early morning mists that cover the forest, including salts dissolved in water by transpiration during the day and, at night, the oozing of sap rich in sugars, minerals, and potassium from the edges of leaves.
Thus invisibly tiny grains of potassium salts, generated by natural plants and other living things at night and early in the morning, play a key role in the formation of aerosols in the rainforest.
Terpenes and isoprenes are primarily released in the gas phase by plants in the jungle, and once in the atmosphere they react with water, oxygen, and organic compounds, acids, and other chemicals exuded by indigenous plants. These reaction products are less volatile and initiate the condensation within the low-lying forest biosphere. Since the smallest particles are typically the most important in condensation, potassium salts fill the role. As the day goes on, gas-phase products continue to condense and the particles continue to grow.
Throughout the rainy season the cloud cover, precipitation, water cycle, and finally the climate of the Amazon basin and beyond can be traced back to salts from fungi and plants in the undisturbed jungle, providing the precursors of natural cloud-condensation nuclei and directly influencing how fog and clouds form and evolve in the rainforest.
Deforestation decreases tropical rainfall, says study
Photo credit: CIAT
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New research on the way air carries moisture confirms that deforestation has a major effect on tropical rainfall.
A team from the University of Leeds and the NERC Centre for Ecology & Hydrology found that over large regions of the tropics air that had travelled over a more forested landscape in the preceding few days produced at least twice as much rain as air that had travelled over deforested land.
By combining these observations with a future projection of Amazonian deforestation, the researchers estimate up to 21 per cent less rainfall in the dry season across the Amazon basin by 2050.
Dr. Dominick Spracklen from the University of Leeds is lead author of the report which is published in Nature. He said:
The predicted reduction in rainfall due to deforestation is equivalent to the severe drought in the Amazon in 2010.
When forests are replaced by pasture or crops, it can reduce the amount of evapotranspiration (ET) – the recycling of moisture back into the atmosphere by leaves. So the air that has travelled over deforested areas is less humid, which one might expect would lead to lower rainfall.
But while there’s plenty of anecdotal evidence that forests increase rainfall, the scientific evidence is not conclusive – does vegetation produce rain or vice versa?
This study aimed to demonstrate the link, and understand the reasons behind it.
Using newly available satellite data on rainfall patterns and leaf cover, the researchers confirmed a strong positive relationship between the exposure of air masses to vegetation and the rainfall they produce – in other words air that has passed over more forests does rain more.
The next step was to understand the reason for this relationship. Spracklen said:
We wanted to explore possible mechanisms behind the correlations we had discovered. So we looked at what had been happening to the air over previous days – where it came from and how much forest it had travelled over.
To understand the relationship in detail, the team investigated the journey of air masses arriving over different parts of the forest, to see the cumulative amount of leaf cover the air had moved over during the previous ten days, not just the amount of vegetation it was over when it rained.
This showed that the more vegetation the air had travelled over, the more moisture it carried. They also demonstrated that this additional moisture was consistent with additional ET being released from vegetated landscapes – strong evidence that the extra rainfall observed is in fact caused by increased exposure to vegetation.
This has important implications for people living and working at the rainforest margins. There isn’t much leaf cover in these regions but it still rains because the air brings moisture from the swathes of rainforest upwind. So deforestation thousands of miles away could interfere with agriculture and industry on the forest margins.
Policies aimed at protecting rainforests need to consider their influence on rainfall over a wider area – this research indicates that just retaining forested patches would not be enough to maintain tropical rainfall levels either over or around the rainforests
James Holden explores life thriving at undersea volcanoes
Undersea black smoker with Alvin mechanical arm
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In 2012, scientists completed a first-ever study with detailed data on the limits of life that thrives deep in the cracks of hot undersea volcanoes, places called hydrothermal vents. The microbes that live in the ocean depths inhale hydrogen and carbon dioxide and exhale methane. And they might even give scientists answers to questions about alien life, beyond Earth. EarthSky spoke to study co-author and microbiologist James Holden of the University of Massachusetts at Amherst. He told us:
There is a tremendous, enormous amount of microbial biomass living within the Earth’s crust in the sediments. Some estimates are that it’s about 1/3 of the total biomass. Others have suggested that it may even rival the biomass that’s living on the surface of the planet.
James Holden (left) with Helene Ver Eecke in undersea vehicle Alvin, with Alvin pilot Bruce Strickrott in The Deep. via Bruce Strickrott/WHOI.
Dr. Holden’s lab took the research sub called Alvin out to hydrothermal vents in the Pacific Ocean, off the coast of the U.S. states of Washington and Oregon. They collected samples of microbes under the sea – then brought them back to their lab to grow them there – in order to test the limits of how much hydrogen these microbes need to grow.
This study also is important because it helps us to understand environments that are independent, free of sunlight and oxygen. The organisms that we study don’t require these compounds. So it helps us to understand what life may have been like, say, on the early Earth, three billion years ago. Or what life might even be like beyond Earth.
Places such as Jupiter’s icy moon Europa, or even the dry desert landscape of the planet Mars, might have had hydrothermal vents and environments much like those in the deep sea of Earth. Holden said:
We think that if there is life, say, on Mars, or on Europa, then it’s going to be similar kinds of life. Life that’s independent of sunlight and life that’s independent of oxygen. So by understanding the life and the constraints on the life that lives in these hydrothermal environments, it gives us some idea of what to expect we can expect on these other planets and how we might be able to model this life, using computer models.And that way, if we do look for life on Mars, where should we look for it? And what should we be looking for? It’d be based on what we know that’s here in similar environments on Earth.
Undersea vehicle Alvin extends its mechanical arm to a high-temperature black smoker in the ocean depths. This image is from what scientists call the Endeavor Segment, at the Juan de Fuca Ridge in the Pacific Ocean Image via Bruce Strickrott/WHOI.
Holden said there might still be some hydrothermal activity on Mars today.
We think that there was past hydrothermal vent activity on Mars. And there may still be some hydrothermal activity on Mars today. We don’t really know. So it’s possible that there still is water circulating in the crust of Mars that’s being driven by a heat source and has some gas coming to it. Or that this certainly happened in the past.Likewise with the Jovian moon Europa, even though it’s completely covered in an ice shell, we think that there’s liquid water underneath that ice. And because of what’s called tidal flexing, where the moons get squished back and forth because of the gravitational pull of Jupiter and the other moons, we think that there’s a lot of volcanic activity on Europa.So, because there’s liquid water, and there’s volcanic activity, there may be hydrothermal vents deep below the ice on Europa as well.
Hydrothermal vent field at Axial Volcano seen through the porthole of the submersible Alvin via Mark Spear/WHOI
He said this research would lead to a greater understanding of how life in general functions.
Life is remarkably flexible, especially microbial life. It is capable of metabolizing all sorts of things that we can hardly dream of – consuming different types of gases and reacting with metals, rocks, and all sorts of different things. Hydrothermal vents give us an opportunity to really explore and understand just how diverse life is, and how it is that life can live in really extreme conditions and in extreme environmentsAnd from that, we can begin to understand the primary principles of how life functions.That understanding opens up all sorts of possibilities – in medicine, in technology, in the search for life elsewhere – if we can understand those basic principles of how life operates.
