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The biggest volcano on Earth is Hawaii’s Mauna Loa, rising to an elevation of 4,169 above sea level and with an estimated volume of 75,000 cubic kilometers. But did you know that Mauna Loa is also the largest active volcano? Mauna Loa’s most recent eruption started on March 24, 1984 and lasted until April 15, 1984. An eruption that recent makes it a very active volcano.
Mauna Loa is the biggest volcano in the world because it’s so active. The enormous mass of the volcano is pushing down on the sea floor, creating a deep depression that it’s sinking down into. Furthermore, the mass of the volcano is causing it to further settle and flatten out. When volcanoes start out, the new eruptions cause them to gain elevation faster than they shrink through settling and erosion. But when a volcano gets really large, it has to erupt regularly to continue gaining elevation.
The size and shape of Mauna Loa is still changing; although, very slowly. The caldera at the summit of Mauna Loa recently opened up about 10 cm during a period of eruption in 1975, and it’s believed that the peak was lifted up by about 13 cm. But then in the 1984 eruption, the peak subsided at least 61 cm. Geologists expect that large portions of Mauna Loa’s flanks will slide off the mountain into the ocean. This will shrink the volcano somewhat, but it will still be the largest volcano in the world.
It’s still a very active volcano, having erupted 33 times since historical records were first kept.
Credit: Louise Kellogg, modified by James Rustad & Qing-zhu Yin/UC Davis
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Earth may have given up its innermost secrets to a pair of California geochemists, who have used extensive computer simulations to piece together the earliest history of our planet’s core.
This schematic of Earth’s crust and mantle shows the results of their study, which found extreme pressures would have concentrated iron’s heavier isotopes near the bottom of the mantle as it crystallized from an ocean of magma.
World Book illustration by Raymond Perlman and Steven Brayfield, Artisan-Chicago
By using a super-computer to virtually squeeze and heat iron-bearing minerals under conditions that would have existed when the Earth crystallized from an ocean of magma to its solid form 4.5 billion years ago, the two scientists — from the University of California at Davis — have produced the first picture of how different isotopes of iron were initially distributed in the solid Earth.
The discovery could usher in a wave of investigations into the evolution of Earth’s mantle, a layer of material about 1,800 miles deep that extends from just beneath the planet’s thin crust to its metallic core.
“Now that we have some idea of how these isotopes of iron were originally distributed on Earth,” said lead study author James Rustad, “we should be able to use the isotopes to trace the inner workings of Earth’s engine.”
A paper describing the study by Rustad and co-author Qing-zhu Yin was posted online by the journal Nature Geoscience on Sunday, June 14, in advance of print publication in July.
Sandwiched between Earth’s crust and core, the vast mantle accounts for about 85 percent of the planet’s volume. On a human time scale, this immense portion of our orb appears to be solid. But over millions of years, heat from the molten core and the mantle’s own radioactive decay cause it to slowly churn, like thick soup over a low flame. This circulation is the driving force behind the surface motion of tectonic plates, which builds mountains and causes earthquakes.
One source of information providing insight into the physics of this viscous mass are the four stable forms, or isotopes, of iron that can be found in rocks that have risen to Earth’s surface at mid-ocean ridges where seafloor spreading is occurring, and at hotspots like Hawaii’s volcanoes that poke up through the Earth’s crust. Geologists suspect that some of this material originates at the boundary between the mantle and the core some 1,800 miles beneath the surface.
“Geologists use isotopes to track physico-chemical processes in nature the way biologists use DNA to track the evolution of life,” Yin said.
Because the composition of iron isotopes in rocks will vary depending on the pressure and temperature conditions under which a rock was created, Yin said, in principle, geologists could use iron isotopes in rocks collected at hot spots around the world to track the mantle’s geologic history. But in order to do so, they would first need to know how the isotopes were originally distributed in Earth’s primordial magma ocean when it cooled down and hardened.
Yin and Rustad investigated how the competing effects of extreme pressure and temperature deep in Earth’s interior would have affected the minerals in the lower mantle, the zone that stretches from about 400 miles beneath the planet’s crust to the core-mantle boundary. Temperatures up to 4,500 degrees Kelvin in the region reduce the isotopic differences between minerals to a miniscule level, while crushing pressures tend to alter the basic form of the iron atom itself, a phenomenon known as electronic spin transition.
The pair calculated the iron isotope composition of two minerals under a range of temperatures, pressures and different electronic spin states that are now known to occur in the lower mantle. The two minerals, ferroperovskite and ferropericlase, contain virtually all of the iron that occurs in this deep portion of the Earth.
The calculations were so complex that each series Rustad and Yin ran through the computer required a month to complete.
Yin and Rustad determined that extreme pressures would have concentrated iron’s heavier isotopes near the bottom of the crystallizing mantle.
The researchers plan to document the variation of iron isotopes in pure chemicals subjected to temperatures and pressures in the laboratory that are equivalent to those found at the core-mantle boundary. Eventually, Yin said, they hope to see their theoretical predictions verified in geological samples generated from the lower mantle.
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As we wait (impatiently) for the Hubble Space Telescope to return to action following its repair and updating by the STS-125 astronauts, it is easy to think about how Hubble has impacted society. Hubble has become a household name, bringing astronomy to the masses with its dramatic images of the cosmos. It has also changed our understanding of the universe. But there’s more ways that HST has impacted the world. Various technologies developed for the famous orbiting telescope have helped create or improve several different medical and and scientific tools. Here are five technology spinoffs from Hubble:
Micro-Endoscope for Medical Diagnosis: Micro-endoscope. Credit: NASA
The same technology that enhances HST’s images are now helping physicians perform micro-invasive arthroscopic surgery with more accurate diagnoses. Hubble technology helped improve the micro-endoscope, a surgical tool that enables surgeons to view what is happening inside the body on a screen, eliminating the need for a more invasive diagnostic procedure. This saves time, money and lessens the discomfort patients experience.
CCDs Enable Clearer, More Efficient Biopsies A biopsy from HST CCD technology. Credit: NASA
Charge coupled devices (CCDs) used on the HST to convert light into electronic files—such as a distant star’s light directly into digital images—have been adapted to improve imaging and optics here on Earth. When scientists realized that existing CCD technology could not meet scientific requirements for the Hubble’s needs, NASA worked with an industry partner to develop a new, more advanced CCD. The industry partner then applied many of the NASA-driven enhancements to the manufacture of CCDs for digital mammography biopsy techniques, using CCDs to image breast tissue more clearly and efficiently. This allows doctors to analyze the tissue by stereotactic biopsy, which requires a needle rather than surgery.
The semiconductor industry has benefitted from the ultra-precise mirror technology that gives the HST its full optical vision and telescopic power. This technological contribution helped improve optics manufacturing in microlithography—a method for printing tiny circuitry, such as in computer chips. The system uses molecular films that absorb and scatter incoming light, enabling superior precision and, consequently, higher productivity and better performance. This translates into better-made and potentially less costly computer circuitry and semiconductors.
Software Enhances Other Observatories Hubble software used by other observatories. Credit: NASA
With the help of a software suite created by a NASA industry partner in 1995, students and astronomers were able to operate a telescope at the Mount Wilson Observatory Institute via the Internet. The software is still widely in use for various astronomy applications; using the CCD technology, the software locates, identifies, and acquires images of deep sky objects, allowing a user to control computer-driven telescopes and CCD cameras.
Optics Tool Sharpens Record-Breaking Ice Skates Hubble technology helps Olympic skaters. Credit: NASA
Current Olympic record-holding speed skater Chris Witty raced her way to a gold medal in the 1,000-meter at the 2002 Salt Lake City Winter Olympics. Witty and other American short- and long-track speed skaters used a blade-sharpening tool designed with the help of NASA Goddard Space Flight Center and technology from HST. NASA had met with the U.S. Olympic Committee and helped to develop a new tool for sharpening speed skates, inspired by principles used to create optics for the HST. Speed skates sharpened with this new instrument demonstrated a marked improvement over conventionally sharpened skates.
Astronaut Chris Cassidy getting strapped into the shuttle. Credit: NASA
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An historic milestone will be reached during the STS-127 space shuttle mission to the International Space Station, which will hopefully launch on Wednesday. The crew will include the 500th person ever to fly in space. Since there are four rookie astronauts on the mission, it’s a bit of a coin toss as to who is actually the 500th, but seemingly the crew has agreed that former naval commander Chris Cassidy, 39, who has led combat missions in Afghanistan, will take the honor.
A few notables of the 499 who have gone before, below, and a quick report that things look good so far for Endeavour’s second launch attempt. NASA is shooting for 5:40:52 a.m. Wednesday (9:40 GMT) on Wednesday June 17.
Workers on Kennedy Space Center's Launch Pad 39A prepare to remove the 7-inch quick disconnect and flight seal from the Ground Umbilical Carrier Plate, or GUCP, on space shuttle Endeavour's external fuel tank. Teams are removing the hardware to change out seals in the internal connection points. The GUCP is the overboard vent to the pad and the flare stack where the vented hydrogen is burned off. Credit: NASA
Click on image for a really huge version.
On Tuesday, engineers pulled a protective gantry away from the shuttle Endeavour and restarted the orbiter’s countdown Tuesday, setting the stage for launch. There are no technical problems of any significance and forecasters are predicting an 80 percent chance of good weather at launch time. You can watch NASA TV or follow Nancy on Twitter for updates.
Looming vertical structures, seen here for the first time and created by Saturn's moon Daphnis, rise above the planet's otherwise flat, thin disk of rings to cast long shadows in this Cassini image. Credit: CICLOPS.
Cassini has imaged towering vertical structures in the planet’s otherwise flat rings that come from the gravitational effects of a small nearby moon. This is the first time these structures have been seen. They reach up over one kilometer high, and are visible now as the sun nears “high noon” directly overhead at the planet’s equator, as Saturn approaches its equinox.
The search for ring material extending above and below Saturn’s ring plane has been a major goal of the imaging team during Cassini’s “Equinox Mission,” the two-year period containing the exact equinox. This novel illumination geometry, which occurs every half-Saturn-year, or about 15 Earth years, lowers the sun’s angle to the ring plane and causes out-of-plane structures to cast long shadows across the rings, making them easy to detect.
Images taken in recent weeks have demonstrated how small moons in very narrow gaps can have considerable and complex effects on the edges of their gaps, and that such moons can be smaller than previously believed. Looming vertical structures, seen here for the first time and created by Saturn's moon Daphnis, rise above the planet's otherwise flat, thin disk of rings to cast long shadows in this Cassini image. Credit: CICLOPS
The 8-kilometer-wide (5-mile) moon Daphnis orbits within the 42-kilometer-wide (26-mile) Keeler Gap in Saturn’s outer A ring, and its gravitational pull perturbs the orbits of the particles forming the gap’s edges. Earlier images have shown “waves” in the rings from Daphnis eccentric orbit.
But new images show the shadows of the vertical waves created by Daphnis cast onto the nearby ring. These characteristics match what was predicted by scientists.
Scientists have estimated, from the lengths of the shadows, wave heights that reach enormous distances above Saturn’s ring plane – as large as 1.5 kilometers (1 mile) — making these waves twice as high as previously known vertical ring structures, and as much as 150 times as high as the rings are thick. The main rings — named A, B and C — are only about 10 meters (30 feet) thick.
“We thought that this vertical structure was pretty neat when we first saw it in our simulations,” said John Weiss, lead author of a paper reporting on these images. “But it’s a million times cooler to have your theory supported by such gorgeous images. It makes you suspect you might be doing something right.”
Click here to watch a movie of the vertical structures and waves in motion.
Also presented in the paper is a refinement to a theory used since the Voyager missions of the 1980s to infer the mass of gap-embedded moons based on how much the moons affect the surrounding ring material. The authors conclude that an embedded moon in a very narrow gap can have a smaller mass than that inferred by earlier techniques. One of the prime future goals of the imaging team is to scour the remaining gaps and divisions within the rings to search for the moons expected to be there. “It is one of those questions that have been nagging us since getting into orbit: ‘Why haven’t we yet seen a moon in every gap?’” said Carolyn Porco, lead for the Cassini imaging team. “We now think they may actually be there, only a lot smaller than we expected.”
The heliosphere is often described as a kind of bubble that contains our solar system. This magnetic sphere, which extends beyond Pluto, is caused by the Sun’s solar winds. These winds spread out from the Sun at around 400 km/s until they hit what is known as interstellar space, which is also called local interstellar medium (LISM) or interstellar gas. Interstellar space is the space in galaxies that is unoccupied by either stars or planets.
When the solar winds hit local interstellar medium, a kind of bubble forms that prevents certain material from getting in. Thus, the heliosphere acts as a kind of shield that protects our solar system from cosmic rays, which are dangerous interstellar particles. The interaction between interstellar gas and solar winds depends on the pressure of the solar winds and properties of interstellar space, such as pressure, density, and qualities of the magnetic field. Astronomers believe that other solar systems have their own heliospheres caused by different stars.
There are several different parts of the heliosphere. The heliopause is the boundary between the heliosphere and the LISM. When solar winds approach this blurred region, they slow abruptly causing a shock wave to form known as the solar wind termination shock. The action is similar to slamming down on the brakes in a car, causing people and objects in the car to fly forward. This shock wave actually causes the particles to accelerate, aiding in the formation of the heliosphere. After it has slowed down, the winds of interstellar space act on the solar winds causing them to curve forming what has been described as a comet-like tail to the Sun. This tail, which has been examined by NASA’s probes Voyager 1 and Voyager2, is called the heliosheath. The termination shock is from around 75 to 90 astronomical units (AU) from our Sun, and at its closest point, the heliosheath is approximately 80 to 100 AU from the Sun.
Astronomers monitoring the Sun have noticed that solar winds have decreased to all-time lows. This affects the heliosphere, which in turn can affect Earth and other planets in the solar system. With solar winds lessening, astronomers fear that the strength of the heliosphere will also decrease, leaving our solar system vulnerable to dangerous cosmic rays. Because solar winds are cyclical, some scientists believe that instead of permanently decreasing, the solar winds are merely experiencing a lengthy low period.
Philipp Heck with the Allende Meteorite. Credit: Dan Dry
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Maybe we’re not as old as we think (or feel?). The interstellar stuff that was integrated into the planets and life on Earth has younger cosmic roots than theories predict, according to the University of Chicago scholar Philipp Heck and his international team of colleagues.
Heck’s team analyzed 22 interstellar grains from the Murchison meteorite. Dying sun-like stars flung the Murchison grains into space more than 4.5 billion years ago, before the birth of the solar system. Scientists know the grains formed outside the solar system because of their exotic composition.
“The concentration of neon, produced during cosmic-ray irradiation, allows us to determine the time a grain has spent in interstellar space,” Heck said. His team determined that 17 of the grains spent somewhere between three million and 200 million years in interstellar space, far less than the theoretical estimates of approximately 500 million years. Only three grains met interstellar duration expectations (two grains yielded no reliable age).
“The knowledge of this lifetime is essential for an improved understanding of interstellar processes, and to better contain the timing of formation processes of the solar system,” Heck said. A period of intense star formation that preceded the sun’s birth may have produced large quantities of dust, thus accounting for the timing discrepancy, according to the research team.
And if you’re interested in looking back, here’s an archive to all the past Carnivals of Space. If you’ve got a space-related blog, you should really join the carnival. Just email an entry to [email protected], and the next host will link to it. It will help get awareness out there about your writing, help you meet others in the space community – and community is what blogging is all about. And if you really want to help out, let Fraser know if you can be a host, and he’ll schedule you into the calendar.
Finally, if you run a space-related blog, please post a link to the Carnival of Space. Help us get the word out.
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Most scientists predict that in about a billion years, the sun’s ever-increasing radiation will have scorched the Earth beyond habitability. The breathable air will be toast, the carbon dioxide that serves as food for plant life will disappear, the oceans will evaporate; and all living things will disappear. Or maybe not. A group of researchers from Caltech have studied a mechanism which would cause any planet with living organisms to remain habitable longer than originally thought, perhaps doubling the lifespan. This sounds like good news for future inhabitants of Earth, but also, this mechanism could increase the chance that life elsewhere in the Universe might have the time to progress to advanced levels.
The researchers say that atmospheric pressure is a natural climate regulator for a terrestrial planet with a biosphere. Currently, and in the past, Earth has maintained its surface temperatures through the greenhouse effect. There used to be greater amounts of CO2 and other greenhouse gases in the atmosphere 1 billion years ago, which was a good thing. Otherwise, the Earth might have been a frozen ice cube. But as the sun’s luminosity and heat increased as it has aged, Earth has naturally coped by reducing the amount of greenhouse gases in the atmosphere, thus reducing the warming effect and making the surface of the planet comfortably habitable.
Opposite of what most scientists claim however, Caltech professor Joseph L. Kirschvink says that Earth may be nearing the point where there’s not enough carbon dioxide left to regulate temperatures using that same procedure. But not to fear, there’s another mechanism underway that may work even better to regulate temperatures on Earth, keeping our home planet comfortable for life even longer than anyone ever predicted. Atmospheric pressure: Credit: Hulu.com
In their paper, Kirschvink and his collaborators Caltech professor Yuk L. Yung, and graduate students King-Fai Li and Kaveh Pahlevan show that atmospheric pressure is a factor that adjusts the global temperature by broadening infrared absorption lines of greenhouse gases. Their model suggests that by simply reducing the atmospheric pressure, the lifespan of a biosphere can be extended at least 2.3 billion years into the future, more than doubling previous estimates.
The researchers use a “blanket” analogy to explain the mechanism. For greenhouse gases, carbon dioxide would be represented by the cotton fibers making up the blanket. “The cotton weave may have holes, which allow heat to leak out,” explains Li, the lead author of the paper.
“The size of the holes is controlled by pressure,” Yung says. “Squeeze the blanket,” by increasing the atmospheric pressure, “and the holes become smaller, so less heat can escape. With less pressure, the holes become larger, and more heat can escape,” he says, helping the planet to shed the extra heat generated by a more luminous sun.
The solution is to reduce substantially the total pressure of the atmosphere itself, by removing massive amounts of molecular nitrogen, the largely nonreactive gas that makes up about 78 percent of the atmosphere. This would regulate the surface temperatures and allow carbon dioxide to remain in the atmosphere, to support life.
This wouldn’t have to be done synthetically – it appears to happen normally. The biosphere itself takes nitrogen out of the air, because nitrogen is incorporated into the cells of organisms as they grow, and is buried with them when they die.
In fact, “this reduction of nitrogen is something that may already be happening,” says Pahlevan, and that has occurred over the course of Earth’s history. This suggests that Earth’s atmospheric pressure may be lower now than it was earlier in the planet’s history. A possible habitable world? Credit: NASA/JPL
Proof of this hypothesis may come from other research groups that are examining the gas bubbles formed in ancient lavas to determine past atmospheric pressure: the maximum size of a forming bubble is constrained by the amount of atmospheric pressure, with higher pressures producing smaller bubbles, and vice versa.
If true, the mechanism also would potentially occur on any extrasolar planet with an atmosphere and a biosphere.
“Hopefully, in the future we will not only detect earth-like planets around other stars but learn something about their atmospheres and the ambient pressures,” Pahlevan says. “And if it turns out that older planets tend to have thinner atmospheres, it would be an indication that this process has some universality.”
The researchers hope atmospheres of exoplanets can be studied to see if this is occurring on other worlds.
And if the duration of habitability could be longer on our own planet, this might have implications for finding intelligent life elsewhere in the Universe.
“It didn’t take very long to produce life on the planet, but it takes a very long time to develop advanced life,” says Yung. On Earth, this process took four billion years. “Adding an additional billion years gives us more time to develop, and more time to encounter advanced civilizations, whose own existence might be prolonged by this mechanism. It gives us a chance to meet.”
Pretty pictures of volcanoes are nice, but to really appreciate the power and fury of a volcano check out some volcano videos.
Here’s a video of the Kilauea volcano in Hawaii. The lava pouring out of Kilauea flows very easily, so it can travel for long distances and create lava fountains and lakes.
Here’s a preview of National Geographic’s documentary video, Inside a Volcano. You can see different kinds of volcanoes erupting. Very spectacular.
Also from National Geographic, this is their volcano 101 video. It shows you the basics of how volcanoes work, how they form, and the different kinds of eruptions.
Here’s a video of an underwater volcano presented by Wired.com. You can see what happens when hot ash and lava meets cold sea water. Did you know that 75% of all volcanoes are underwater volcanoes, and most of those are never detected.
Finally, here’s a video from the Discovery Channel with links and video of the 5 best volcano web cams. It’s a great tour through some of the coolest volcano webcams on the planet.
We have written many article about volcanoes for Universe Today. Here’s an article about
